Abstract Background Vancomycin-induced bleeding has been reported, attributed to the mechanism of immune thrombocytopenia. A rare case of vancomycin-induced gastrointestinal hemorrhage in a young patient with no underlying disease, receiving intravenous vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) infection, is presented. This occurrence occurred without thrombocytopenia. Relevant cases reported in the literature were also reviewed. Case presentation A 34-year-old male patient presented with maxillofacial multiple spaces infection accompanying left temporal abscess, bilateral lung abscesses. Culture results from both blood and secretion indicated that the infection was caused by MRSA. The patient received standard-dose vancomycin (1 g q12h intravenously guttae) for treatment. On the 5th day of therapy, he presented with bright red blood in his stool; however, vancomycin treatment was continued. By the 9th day, a decrease in hemoglobin level to 76 g/L and a platelet (PLT) count of 424 × 109/L raised concerns about gastrointestinal hemorrhage. The hemoglobin level decreased to 62 g/L on day 12. Due to the high tissue concentration of linezolid, administration of linezolid at a dose of 600 mg q12h intravenously guttae commenced on the 13th day as an alternative to vancomycin(D13-D17). Subsequently, on the 17th day, there was an improvement in hemoglobin level to 78 g/L. However, despite treatment with linezolid, the patient’s fever showed no significant improvement, prompting a switch back to vancomycin at a dosage of 1 g q12h intravenously guttae(D18-D22). On the 21st day, there was a recurrence of gastrointestinal hemorrhage, accompanied by a hemoglobin level of 42 g/L and a PLT count of 224 × 109/L. Gastroscopy revealed the presence of a gastroduodenal ulcer. The patient had no prior history of hemorrhoids, gastrointestinal ulcers, liver cirrhosis, or purpura. Prior to admission, he had not been administered non-steroidal anti-inflammatory drugs (NSAIDs) or steroids. During hospitalization, the only medications given were vancomycin, ambroxol and lidocaine. Additional tests ruled out immunological disorders as the cause of gastrointestinal ulcers, and a positive vancomycin rechallenge test indicated an association between vancomycin and bleeding. After discontinuation of vancomycin, no further bleeding occurred. This case highlights a rare occurrence of vancomycin-induced bleeding without thrombocytopenia, classified as “Certain” according to the World Health Organization-Uppsala Monitoring Centre (WHO-UMC) scale for standardized case causality assessment. Conclusion This case represents the first documented instance of vancomycin-induced bleeding without thrombocytopenia, as confirmed by a positive rechallenge test. This discovery will aid in the early detection of this rare adverse reaction in future cases. …

Abstract Background and rationale Methicillin resistant Staphylococcus aureus (MRSA) colonization increases the risk of MRSA infection. Detecting MRSA colonization can influence postoperative outcomes and prolong hospital stay. The conventional standard culture method for detecting MRSA colonization has limitations in terms of sensitivity and turnaround time. Hence, we sought out use of Xpert PCR kit for prompt evaluation of MRSA colonization to support MRSA prevention in a tertiary care hospital in Karachi, Pakistan. Materials and methods During 1st April-31st December 2022, 290 nasal and skin swab samples were collected from 257 patients and processed using routine culture (as gold standard method) and PCR-based MRSA detection assay (MRSA Xpert). Results A total of two hundred and ninety (290) swab samples from 257 patients were obtained, 33 of which were paired. The overall prevalence of MRSA colonization was 12% by both methods, with 90% of cases classified as community-associated (CA-MRSA) whereas 10% as hospital-acquired (HA-MRSA). The colonized group showed a higher subsequent MRSA infection rate (11% vs. 3.5%) compared to the noncolonized group. Culture identified 11% of screening samples as MRSA positive, Xpert MRSA assay showed 100% sensitivity and 95% specificity. The cost of a single MRSA Xpert assay was $50 while MRSA culture cost around $7.50. Conclusion Our study findings suggest that the presence of MRSA colonization in our cohort of patients is consistent with the existing trends in hospital epidemiology. Both conventional culture and Xpert MRSA methods showed comparable efficacy for detection of MRSA colonization. Larger-scale studies are recommended to validate these findings conclusively. …

Abstract Background and rationale Methicillin resistant Staphylococcus aureus (MRSA) colonization increases the risk of MRSA infection. Detecting MRSA colonization can influence postoperative outcomes and prolong hospital stay. The conventional standard culture method for detecting MRSA colonization has limitations in terms of sensitivity and turnaround time. Hence, we sought out use of Xpert PCR kit for prompt evaluation of MRSA colonization to support MRSA prevention in a tertiary care hospital in Karachi, Pakistan. Materials and methods During 1st April-31st December 2022, 290 nasal and skin swab samples were collected from 257 patients and processed using routine culture (as gold standard method) and PCR-based MRSA detection assay (MRSA Xpert). Results A total of two hundred and ninety (290) swab samples from 257 patients were obtained, 33 of which were paired. The overall prevalence of MRSA colonization was 12% by both methods, with 90% of cases classified as community-associated (CA-MRSA) whereas 10% as hospital-acquired (HA-MRSA). The colonized group showed a higher subsequent MRSA infection rate (11% vs. 3.5%) compared to the noncolonized group. Culture identified 11% of screening samples as MRSA positive, Xpert MRSA assay showed 100% sensitivity and 95% specificity. The cost of a single MRSA Xpert assay was $50 while MRSA culture cost around $7.50. Conclusion Our study findings suggest that the presence of MRSA colonization in our cohort of patients is consistent with the existing trends in hospital epidemiology. Both conventional culture and Xpert MRSA methods showed comparable efficacy for detection of MRSA colonization. Larger-scale studies are recommended to validate these findings conclusively. …

Abstract Background In the pediatric population, Staphylococcus aureus infections are responsible for increased morbidity and mortality, length of hospitalization and the cost of inpatient treatment. The aim of this study is to describe the antimicrobial resistance profile of S. aureus isolated in clinical specimens from pediatric patients admitted to a tertiary hospital in Rio de Janeiro, Brazil. Methods Culture reports and medical records of hospitalized patients under 18 years of age with S. aureus infections between January 2015 and December 2022 were retrospectively analyzed. Information was collected on recent antibiotic use, previous hospital admission, inpatient unit, clinical specimen, time of infection (community or nosocomial), classification according to susceptibility to methicillin (methicillin sensitive - MSSA or methicillin resistant - MRSA) and sensitivity to other antimicrobials. We analyzed the distribution of the sensitivity profile of S. aureus infections over the 7 years evaluated in the study. Results Were included 255 unique clinical episodes, among which the frequencies of MSSA and MRSA were 164 (64%) and 91 (36%), respectively. Over the 7 years evaluated, there was stability in the prevalence percentage, with a predominance of MSSA in the range of 60 to 73.3%, except in 2020, when there was a drop in the prevalence of MSSA (from 73.3% in 2019 to 52.5%) with an increase in MRSA (from 26.7% in 2019 to 47.5%). Ninety-seven (38%) infections were community-acquired and 158 (62%) were healthcare-associated. The main clinical specimens collected were blood cultures (35.2%) and wound secretions (17%). The MRSA isolates presented percentages of sensitivity to trimethoprim-sulfamethoxazole from 90.4 to 100%, and to clindamycin from 77 to 89.8% in MRSA healthcare associated and MRSA community respectively. Conclusion There was a constant predominance in the prevalence of MSSA with percentage values ​​maintained from 2015 to 2022, except in 2020, in which there was a specific drop in the prevalence of MSSA with an increase in MRSA. MSSA infections are still predominant in the pediatric population, but MRSA rates also present significant values, including in community infections, and should be considered in initial empiric therapy. …

by Mohammed S. Almuhayawi, Mohammed H. Alruhaili, Mohamed K. Y. Soliman, Muyassar K. Tarabulsi, Ruba A. Ashy, Amna A. Saddiq, Samy Selim, Yasir Alruwaili, Salem S. Salem It is thought to be risk-free, environmentally benign, and safe for biological processes to produce zinc oxide nanoparticles from renewable resources. This study examined Cassia javanica’s ability to create ZnONPs. The generated ZnONPs were analyzed using a variety of techniques, such as TEM, FTIR spectroscopy, UV-Vis spectroscopy, and XRD analysis. The antibacterial potential of ZnONPs has been investigated using both Agar well diffusion and microtitreplate (MTP) methods. One method used to evaluate ZnONPs’ capacity to scavenge free radicals at different concentrations was the DPPH method. The permanent zinc oxide (ZnO) shape and the naturally occurring crystal structure of ZnONPs were validated by the XRD data. ZnONPs showed antibacterial activity with MICs of 31.7 μg/mL toward Bacillus subtilis, 62.5 μg/mL for Salmonella typhimurium, Escherichia coli while Clostridium sporogenes and Bacillus pumilus was 125μg/mL. Furthermore, ZnONPs demonstrated a range of antibiofilm activities toward Staphylococcus aureus (MRSA). ZnONPs showed an intriguing antioxidant capacity, achieving IC50 of 109.3 μg/ml μg/mL. Additionally, ZnONPs demonstrated low toxic effect on Vero cell with IC50 154.01 μg/mL as well as possible anticancer action when applied to the carcinoma cell lines HepG2 with IC50 of 47.48 μg/mL. Furthermore, ZnONPs at 62.5 μg/mL had a promising antiviral impact against HSV1 and COX B4, with antiviral activities of 75.4% and 65.8%, respectively.

Abstract Background In the pediatric population, Staphylococcus aureus infections are responsible for increased morbidity and mortality, length of hospitalization and the cost of inpatient treatment. The aim of this study is to describe the antimicrobial resistance profile of S. aureus isolated in clinical specimens from pediatric patients admitted to a tertiary hospital in Rio de Janeiro, Brazil. Methods Culture reports and medical records of hospitalized patients under 18 years of age with S. aureus infections between January 2015 and December 2022 were retrospectively analyzed. Information was collected on recent antibiotic use, previous hospital admission, inpatient unit, clinical specimen, time of infection (community or nosocomial), classification according to susceptibility to methicillin (methicillin sensitive - MSSA or methicillin resistant - MRSA) and sensitivity to other antimicrobials. We analyzed the distribution of the sensitivity profile of S. aureus infections over the 7 years evaluated in the study. Results Were included 255 unique clinical episodes, among which the frequencies of MSSA and MRSA were 164 (64%) and 91 (36%), respectively. Over the 7 years evaluated, there was stability in the prevalence percentage, with a predominance of MSSA in the range of 60 to 73.3%, except in 2020, when there was a drop in the prevalence of MSSA (from 73.3% in 2019 to 52.5%) with an increase in MRSA (from 26.7% in 2019 to 47.5%). Ninety-seven (38%) infections were community-acquired and 158 (62%) were healthcare-associated. The main clinical specimens collected were blood cultures (35.2%) and wound secretions (17%). The MRSA isolates presented percentages of sensitivity to trimethoprim-sulfamethoxazole from 90.4 to 100%, and to clindamycin from 77 to 89.8% in MRSA healthcare associated and MRSA community respectively. Conclusion There was a constant predominance in the prevalence of MSSA with percentage values ​​maintained from 2015 to 2022, except in 2020, in which there was a specific drop in the prevalence of MSSA with an increase in MRSA. MSSA infections are still predominant in the pediatric population, but MRSA rates also present significant values, including in community infections, and should be considered in initial empiric therapy. …

Abstract Background Corynebacterium striatum (C. striatum), a common skin and mucosal colonizer, is increasingly considered as an opportunistic pathogen causing bloodstream infections (BSIs). This study aims to investigate the clinical features and outcomes of C. striatum-BSI. Methods We included hospitalized cases with C. striatum-positive blood cultures from January 2014 to June 2022 and classified them into C. striatum-BSI group and contamination group; Clinical characteristics, treatments, and outcomes were compared between the C. striatum-BSI group and contamination group, Methicillin-resistant Staphylococcus aureus (MRSA)-BSI and Methicillin-resistant Staphylococcus epidermidis (MRSE)-BSI. Results Fifty-three patients with positive C. striatum blood cultures were identified. Among them, 25 patients were classified as C. striatum-BSI, with 21 as contamination cases. And 62 cases of MRSA-BSI and 44 cases of MRSE-BSI were identified. Compared to the contaminated group, the C. striatum-BSI group had a shorter time to positivity of blood cultures (27.0 h vs. 42.5 h, P = 0.011). C. striatum-BSI group had a longer time to positivity (27 h) when compared to both the MRSA (20 h) and MRSE groups (19 h) (p 

by Zhaolei Wang, Haixia Du, Haofang Wan, Jiehong Yang, Haitong Wan Methicillin-resistant Staphylococcus aureus (MRSA) is an opportunistic pathogen that can cause severe bacterial pneumonia. Amygdalin is the main active pharmaceutical ingredient of bitter almond, which has broad-spectrum antibacterial, anti-inflammatory, anti-oxidation and immunomodulatory effects. It is also the main ingredient of Yinhua Pinggan granule, which is commonly used to moisten the lung and relieve cough. However, little is known about the effects of amygdalin on MRSA. In this study, we found that amygdalin exhibited good antimicrobial activity in vitro against MRSA. Amygdalin has a protective effect on MRSA infected cells, and the effect is better when combined with levofloxacin. It also can reduce the adhesion and invasion of MRSA to cells. Amygdalin has anti-inflammatory and antioxidant effects, which can significantly reduce the increase of inflammatory factors and the production of ROS caused by infection. The protective mechanism of amygdalin on cells may be related to inhibiting the expression of NLRP3, ASC and IL-1β pyroptosis pathways. Taken together, our study suggests that amygdalin exerts antibacterial effects by affecting biofilm formation, the expression of virulence factors, and drug resistance genes. Amygdalin combined with levofloxacin has a protective effect on A549 cells infected with MRSA, and the mechanism may be related to the inhibition of inflammatory response, oxidative damage and pyroptosis.

Abstract Background The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains resistant to non-beta-lactam antimicrobials poses a significant challenge in treating severe MRSA bloodstream infections. This study explores resistance development and mechanisms in MRSA isolates, especially after the first dalbavancin-resistant MRSA strain in our hospital in 2016. Methods This study investigated 55 MRSA bloodstream isolates (02/2015–02/2021) from the University Hospital of the Medical University of Vienna, Austria. The MICs of dalbavancin, linezolid, and daptomycin were assessed. Two isolates (16–33 and 19–362) resistant to dalbavancin were analyzed via whole-genome sequencing, with morphology evaluated using transmission electron microscopy (TEM). Results S.aureus BSI strain 19–362 had two novel missense mutations (p.I515M and p.A606D) in the pbp2 gene. Isolate 16–33 had a 534 bp deletion in the DHH domain of GdpP and a SNV in pbp2 (p.G146R). Both strains had mutations in the rpoB gene, but at different positions. TEM revealed significantly thicker cell walls in 16–33 (p 

Abstract Background The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains resistant to non-beta-lactam antimicrobials poses a significant challenge in treating severe MRSA bloodstream infections. This study explores resistance development and mechanisms in MRSA isolates, especially after the first dalbavancin-resistant MRSA strain in our hospital in 2016. Methods This study investigated 55 MRSA bloodstream isolates (02/2015–02/2021) from the University Hospital of the Medical University of Vienna, Austria. The MICs of dalbavancin, linezolid, and daptomycin were assessed. Two isolates (16–33 and 19–362) resistant to dalbavancin were analyzed via whole-genome sequencing, with morphology evaluated using transmission electron microscopy (TEM). Results S.aureus BSI strain 19–362 had two novel missense mutations (p.I515M and p.A606D) in the pbp2 gene. Isolate 16–33 had a 534 bp deletion in the DHH domain of GdpP and a SNV in pbp2 (p.G146R). Both strains had mutations in the rpoB gene, but at different positions. TEM revealed significantly thicker cell walls in 16–33 (p 

Abstract Background While Streptococcus pneumoniae (Spn) is the leading cause of pediatric complicated community acquired pneumonia (cCAP), it is infrequently recovered by culture-based methods. We studied the real-world clinical impact of an Spn PCR assay for pleural fluid.Methods This pre-post quasi-experimental cohort study compared pathogen detection, antibiotic usage, and outcomes in children hospitalized with cCAP requiring pleural effusion or empyema drainage at Children’s Hospital Colorado between 2016 and 2023. Patients were compared across two diagnostic periods: pre-Spn PCR and post-Spn PCR. Cox proportional hazard models compared time from admission to pathogen detection, optimal therapy (narrowest pathogen-directed or guideline-recommended empiric therapy), and MRSA therapy discontinuation between periods.Results Compared to the pre-Spn PCR cohort (N=149), the post-Spn PCR cohort (N=79) was more likely to have a pathogen detected (73.4% post-PCR vs. 38.9% pre-PCR, p < 0.001), driven by more Spn detections (45.6% vs. 14.1%, p < 0.001). Time to pathogen detection during hospitalization was shorter in the post-Spn PCR period (p < 0.001). The post-PCR cohort was more likely to receive optimal therapy (84.8% vs. 53.0%, p < 0.001), with shorter median times to optimal antibiotics (4.9 vs. 10.0 days, p < 0.001) and MRSA therapy discontinuation (1.5 vs. 2.5 days, p = 0.03). There were no differences in hospital length of stay or readmissions.Conclusions Spn molecular testing of pleural fluid in children with cCAP resulted in significantly more microbiologic diagnoses and was associated with the optimization of antibiotics and decreased exposure to MRSA therapy, suggesting its clinical impact for pediatric complicated pneumonia.

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are associated with high mortality rates. Optimal antibiotic dosage plays a crucial role in reducing MRSA burden; thus, the use of therapeutic drug monitoring (TDM) in the clinical practice, especially of new drugs such as ceftobiprole, ceftaroline, dalbavancin and oritavancin, should be implemented.

Current Infectious Diseases Society of America (IDSA) guidelines recommend the use of vancomycin (VAN) or daptomycin (DAP) monotherapy for the management of methicillin-resistant Staphylococcus aureus bloodstream infection (MRSA-BSI) [1]. Despite being the standard of care, mortality (20-30%) [2-4] and rates of microbiologic failure (10-16%) with this approach remain high [5]. Early efforts to utilize gentamicin synergy has not shown to be effective to improve outcomes of S. aureus BSI [6]. As summarized in Table 1, other combination antibiotic therapies by addition of rifampin, daptomycin, or fosfomycin to standard of therapy for S.

by Sabrina Sultana Rimi, Md. Nahid Ashraf, Sanzila Hossain Sigma, Md. Tanjir Ahammed, Mahbubul Pratik Siddique, Mohammad Ali Zinnah, Md. Tanvir Rahman, Md. Shafiqul Islam Biofilm development significantly enhances the virulence of methicillin-resistant Staphylococcus aureus (MRSA), leading to severe infections and decreased susceptibility to antibiotics, especially in strains associated with hospital environments. This study examined the occurrence of MRSA, their ability to form biofilms, agr typing, and the antibiotic resistance profiles of biofilm-forming MRSA strains isolated from environmental surfaces at Mymensingh Medical College Hospital (MMCH). From 120 swab samples, 86 (71.67%) tested positive for S. aureus. MRSA was identified in 86 isolates using the disk diffusion technique, and by polymerase chain reaction (PCR), 56 (65.1%) isolates were confirmed to carry the mecA gene. The Crystal Violet Microtiter Plate (CVMP) test revealed that 80.35% (45 isolates) were biofilm-forming and 19.6% (11 isolates) were non-biofilm-forming. Out of 45 biofilm producer isolates 37.5% and 42.9% isolates exhibited strong and intermediate biofilm-forming characteristics, respectively. Molecular analysis revealed that 17.78% of MRSA isolates carried at least one gene related to biofilm formation, specifically icaA, icaB, and icaD genes were discovered in 13.33%, 8.89%, 6.67% of the MRSA isolates, respectively. In agr typing, the most prevalent group was agr I (71.11%), followed by group III (17.78%) and group II (11.11%). Group IV was not detected. The distribution of agr gene groups showed a significant difference among biofilm-forming isolates (p < 0.05). In agr group I, 18.75% of isolates carried the icaA gene, 12.5% carried the icaB gene, and 9.37% carried the icaD gene. Biofilm-forming genes were not detected in any of the isolates from agr groups II or III. There are no statistically significant differences between agr groups and the presence of these genes (p > 0.05). Antibiotic resistance varied significantly among agr groups, with agr group I displaying the highest resistance, agr group II, and agr group III exhibiting the least resistance (p < 0.05). Seventy-three (73.3%) of the isolates were multi-drug resistant, with agr group I displaying nineteen MDR patterns. The occurrence of MRSA in hospital environments and their capacity to form biofilm raises concerns for public health. These findings support the importance of further research focused on agr quorum sensing systems as a basis for developing novel antibacterial agents.

by Ayele Assefa, Melat Woldemariam, Addis Aklilu, Dagninet Alelign, Abdurezak Zakir, Aseer Manilal, Temesgen Mohammed, Reham M. Alahmadi, Gurusamy Raman, Akbar Idhayadhulla Background Typical pneumonia is a pressing issue in the treatment of human immunodeficiency virus (HIV) patients, especially in Sub-Saharan Africa, where it remains a significant menace. Addressing this problem is crucial in improving health outcomes and the reduction of the burden of diseases in this vulnerable category of patients. Objective To determine the prevalence of community-acquired typical pneumonia among HIV patients in Public Hospitals in southern Ethiopia. Methods A cross-sectional study was done among 386 HIV patients clinically suspected of typical pneumonia attending the anti-retroviral therapy (ART) clinics of two hospitals from March to September 2022. A pretested structured questionnaire was employed to collect the demographic, clinical, and behavioral data. Sputum samples were collected and inspected for bacteria following standard procedures, and antimicrobial susceptibility testing was performed employing the Kirby-Bauer disk diffusion method. Besides, extended-spectrum β-lactamase (ESβL) and carbapenemase-producing Gram-negative bacteria were inspected by the double disk synergy test and modified carbapenem inactivation method. Descriptive and inferential statistical analyses were also done. Results Overall, 39.1% (151/386) of sputum cultures (95% Confidence Interval: 32.4–44) were bacteriologically positive. A total of 151 bacteria were identified, comprising 72.8% (n = 110) of Gram-negative bacteria. The predominant isolate was Klebsiella pneumoniae (25.8%, n = 39), followed by Staphylococcus aureus (17.9%, n = 27); 59.6% (n = 90) of the entire isolates were multidrug-resistant (MDR). Forty percent (11/27) of S. aureus were methicillin-resistant S. aureus (MRSA), and 28.1% (n = 31) and 20.9% (n = 23) of Gram-negative bacteria were extended-spectrum beta-lactamases (ESBL) and carbapenemase producers, respectively. Occupational status, alcohol consumption, cluster of differentiation4 (CD4) Thymocyte cell count < 350, interruption of trimethoprim-sulfamethoxazole prophylaxis and antiretroviral treatment, and recent viral load ≥ 150 were found statistically significant. Conclusion The higher rates of MDR, MRSA, ESBL, and carbapenem-resistant Enterobacterales (CRE) indicate that bacterial pneumonia is a vexing problem among HIV patients and therefore it is advisable to implement an antimicrobial stewardship program in the study area. …

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of fatal bloodstream infection, with mortality rates of up to 30% reported (1). In low-resource settings, first-line treatment with vancomycin is compromised by availability of the drug, lack of therapeutic drug monitoring (TDM), and cost. The majority of MRSA isolates globally remain susceptible to trimethoprim-sulfamethoxazole (TMP-SMX or co-trimoxazole). This antibiotic is widely available and cheap. TMP-SMX is often recommended as an alternative to vancomycin, particularly as an oral stepdown therapy, but there is a dearth of data assessing its efficacy for initial treatment of MRSA bacteraemia because it has been superseded by newer agents in high-income countries e.g., daptomycin, linezolid, dalbavancin, ceftaroline and ceftobiprole.

Abstract Background Staphylococcus aureus (S. aureus) is one of the most widespread bacterial pathogens in animals and humans, and its role as an important causative agent of food poisoning is well-documented. The aim of this study was to highlight and characterize the resistance patterns of methicillin-resistant S. aureus (MRSA) in charcuterie products sold in selected supermarkets (SM) in Bobo-Dioulasso, Burkina Faso. Methods In this study, 72 samples including ham (n = 19), merguez (n = 22), sausage (n = 15) and minced meat (n = 16) were collected from 3 supermarkets. Standard microbiology methods were utilised to characterise S. aureus isolates. Phenotypic resistance patterns were investigated using the disk diffusion method on Mueller-Hinton agar. Genotypic testing using polymerase chain reaction (PCR) was performed on the isolates to detect the 16S-23S gene. Using specific primers, the following genes PVL, TSST-1, mecA, gyrA, gyrB, qnrA, intI1 and aac(6’)-Ib-cr were identified from purified DNA by PCR. Results Among the 72 ready-to-eat food samples, S. aureus was present in 51, (70.83%). The yield was highest in both the ham and merguez food products, 15/51 (29.41%) each, followed by minced meat 12/51 (23.53%) and sausage 9/51 (17.65%). A total of 35 isolates (68.63%) were confirmed as S. aureus after molecular characterization using 16–23 S primers with 05 (14.29%) strains identified as MRSA. All of the MRSA and majority of the methicillin-sensitive S.aureus (MSSA) isolates were resistant to penicillin G, ampicillin, tetracycline and erythromycin, whereas one isolate from minced meat was found in SM3-harbouring PVL, TSST-1, mecA, gyrA, gyrB and Int1 genes. Conclusions Our study revealed a high prevalence of S. aureus in chacuterie products in Bobo-Dioulasso with antimicrobial profiles that show resistance to most antibiotics. These findings should inform and augment efforts to raise awareness among local supermarket owners on adequate food manufacturing practices as well as promoting food safety and hygiene. …

Abstract Background Staphylococcus aureus (S. aureus) is one of the most widespread bacterial pathogens in animals and humans, and its role as an important causative agent of food poisoning is well-documented. The aim of this study was to highlight and characterize the resistance patterns of methicillin-resistant S. aureus (MRSA) in charcuterie products sold in selected supermarkets (SM) in Bobo-Dioulasso, Burkina Faso. Methods In this study, 72 samples including ham (n = 19), merguez (n = 22), sausage (n = 15) and minced meat (n = 16) were collected from 3 supermarkets. Standard microbiology methods were utilised to characterise S. aureus isolates. Phenotypic resistance patterns were investigated using the disk diffusion method on Mueller-Hinton agar. Genotypic testing using polymerase chain reaction (PCR) was performed on the isolates to detect the 16S-23S gene. Using specific primers, the following genes PVL, TSST-1, mecA, gyrA, gyrB, qnrA, intI1 and aac(6’)-Ib-cr were identified from purified DNA by PCR. Results Among the 72 ready-to-eat food samples, S. aureus was present in 51, (70.83%). The yield was highest in both the ham and merguez food products, 15/51 (29.41%) each, followed by minced meat 12/51 (23.53%) and sausage 9/51 (17.65%). A total of 35 isolates (68.63%) were confirmed as S. aureus after molecular characterization using 16–23 S primers with 05 (14.29%) strains identified as MRSA. All of the MRSA and majority of the methicillin-sensitive S.aureus (MSSA) isolates were resistant to penicillin G, ampicillin, tetracycline and erythromycin, whereas one isolate from minced meat was found in SM3-harbouring PVL, TSST-1, mecA, gyrA, gyrB and Int1 genes. Conclusions Our study revealed a high prevalence of S. aureus in chacuterie products in Bobo-Dioulasso with antimicrobial profiles that show resistance to most antibiotics. These findings should inform and augment efforts to raise awareness among local supermarket owners on adequate food manufacturing practices as well as promoting food safety and hygiene. …

Abstract Background Ruthenibacterium lactatiformans, a Gram-stain-negative, rod-shaped, obligate anaerobic bacterium of the Oscillospiraceae family, has not been previously reported in human infections. This study reports the first case of bacteraemia and potential vertebral osteomyelitis caused by Ruthenibacterium lactatiformans. Case presentation An 82-year-old man with a history of diabetes, chronic renal failure, and prior spinal surgery for spondylolisthesis and spinal stenosis presented with fever and lower back pain. Magnetic resonance imaging revealed multiple vertebral osteomyelitis lesions. Initial blood cultures identified methicillin-resistant Staphylococcus aureus (MRSA), which prompted vancomycin treatment. However, repeated blood cultures not only confirmed persistent MRSA, but also detected Gram-negative bacilli (GNB). Despite surgical removal of the spinal hardware and antimicrobial therapy, the patient’s osteomyelitis worsened, necessitating transfer for further management. Subsequent analysis using 16S rRNA gene sequencing identified the GNB as Ruthenibacterium lactatiformans. Conclusions This is the first documented instance of human infection with Ruthenibacterium lactatiformans, signifying its pathogenic potential in vertebral osteomyelitis. The involvement of anaerobic bacteria and the possibility of polymicrobial infections complicate the diagnosis and treatment of vertebral osteomyelitis. This report underscores the need for caution when identifying the causative organism and selecting an appropriate treatment. …

Abstract Background Ruthenibacterium lactatiformans, a Gram-stain-negative, rod-shaped, obligate anaerobic bacterium of the Oscillospiraceae family, has not been previously reported in human infections. This study reports the first case of bacteraemia and potential vertebral osteomyelitis caused by Ruthenibacterium lactatiformans. Case presentation An 82-year-old man with a history of diabetes, chronic renal failure, and prior spinal surgery for spondylolisthesis and spinal stenosis presented with fever and lower back pain. Magnetic resonance imaging revealed multiple vertebral osteomyelitis lesions. Initial blood cultures identified methicillin-resistant Staphylococcus aureus (MRSA), which prompted vancomycin treatment. However, repeated blood cultures not only confirmed persistent MRSA, but also detected Gram-negative bacilli (GNB). Despite surgical removal of the spinal hardware and antimicrobial therapy, the patient’s osteomyelitis worsened, necessitating transfer for further management. Subsequent analysis using 16S rRNA gene sequencing identified the GNB as Ruthenibacterium lactatiformans. Conclusions This is the first documented instance of human infection with Ruthenibacterium lactatiformans, signifying its pathogenic potential in vertebral osteomyelitis. The involvement of anaerobic bacteria and the possibility of polymicrobial infections complicate the diagnosis and treatment of vertebral osteomyelitis. This report underscores the need for caution when identifying the causative organism and selecting an appropriate treatment. …

by Diana Celi, Evelyn Quiroz, Andrea Beltrán-Noboa, António Machado, Eduardo Tejera, Paulina Fernandez-Soto The Pelargonium genus encompasses around 280 species, most of which are used for medicinal purposes. While P. graveolens, P. odoratissimum, and P. zonale are known to exhibit antimicrobial activity, there is an evident absence of studies evaluating all three species to understand their chemical differences and biological effects. Through the analysis of the hydroalcoholic extracts of P. graveolens, P. odoratissimum, and P. zonale, using HPLC-DAD-MS/MS, quercetin and kaempferol derivatives were identified in these three species. Conversely, gallotannins and anthocyanins were uniquely detected in P. zonale. P. graveolens stood out due to the various types of myricetin derivatives that were not detected in P. odoratissimum and P. zonale extracts. Evaluation of their biological activities revealed that P. zonale displayed superior antibacterial and antibiofilm activities in comparison to the other two species. The antibacterial efficacy of P. zonale was observed towards the clinically relevant strains of Staphylococcus aureus ATCC 25923, Methicillin-resistant Staphylococcus aureus (MRSA) 333, Enterococcus faecalis ATCC 29212, and the Vancomycin-resistant E. faecalis INSPI 032. Fractionation analysis of P. zonale suggested that the antibacterial activity attributed to this plant is due to the presence of quercetin derivatives and kaempferol and its derivatives, alongside their synergistic interaction with gallotannins and anthocyanins. Lastly, the three Pelargonium species exhibited notable antioxidant activity, which may be attributed to their high content of total phenolic compounds.

by Cecilia Rodriguez, Dema Ramlaoui, Briea Gasca, Adiba Azis, Camila Leal, Christina Lopez, Vyanka Merzcord, Kirsten S. McManus, Jasmin Jo, Silvia I. Cazorla, Tomás Subils, Marisel R. Tuttobene, Nicholas T. Salzameda, Robert A. Bonomo, Luis A. Actis, Raúl Raya, María Soledad Ramirez A growing increase in the number of serious infections caused by multidrug resistant bacteria (MDR) is challenging our society. Despite efforts to discover novel therapeutic options, few antibiotics targeting MDR have been approved by the Food and Drug Administration (FDA). Lactic acid bacteria have emerged as a promising therapeutic alternative due to their demonstrated ability to combat MDR pathogens in vitro. Our previous co-culture studies showed Lacticaseibacillus rhamnosus CRL 2244 as having a potent killing effect against carbapenem-resistant Acinetobacter baumannii (CRAB) strains. Here we report that cell-free conditioned media (CFCM) samples obtained from Lcb. rhamnosus CRL 2244 cultures incubated at different times display antimicrobial activity against 43 different pathogens, including CRAB, methicillin-resistant Staphylococcus aureus (MRSA) and carbapenemase Klebsiella pneumoniae (KPC)-positive strains. Furthermore, transwell and ultrafiltration analyses together with physical and chemical/biochemical tests showed that Lcb. rhamnosus CRL 2244 secretes a…

Abstract Background CKD patients on hemodialysis (HD) with Staphylococcus aureus (SA) bacteremia present high morbidity, mortality and increased risk of MRSA. Vancomycin is the antibiotic of choice in these cases, it has a narrow therapeutic margin and inadequate dosage generates a risk of toxicity, therefore, the recommendation is to dosage it through serum levels. Methods This is a retrospective cohort study in 3 hospitals of third level of complexity in the city of Medellin in which there were differences in the measurement and implementation of vancomycin25 dosage based on trough levels (VL) in patients with chronic kidney disease on hemodialysis (CKD- HD) with uncomplicated bacteremia based infection by methilcillin-resistant Staphyloccocus aureus (MRSA). The primary outcome was the composite of hospital mortality, clinical response (fever, hemodynamic instability and altered consciousness), complications associated with bacteremia, or bacteriological response failure (positive cultures at first week follow-up) at 7 days. The composite variables were analyzed individually as secondary outcomes. Results The main unadjusted outcome (OR 1.3, CI 0.6 - 2.7) and adjusted for age, Charlson index, loading dose, initial dose, dosing frequency and MIC to vancomycin (OR 1.2, CI 0.5 - 2.7). Regarding adjusted secondary outcomes: clinical response (OR 1.4 CI 0.3 - 5.8), death (OR 1.3 CI 0.3 - 4.6) and complications (OR 0.9, CI 0.37 - 2.2). Conclusions We conclude that the measurement of trough levels in patients with HD-CKD does not modify the composite outcome. The main limitation is the sample size and type of study, randomized control trials may be required to confirm the results presented. …

This review aims to explore the characteristics of outbreaks of community-acquired community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) in low prevalence areas, to understand the factors involved in its rise, and to translate this knowledge into public health policy and further research needs.

Abstract Background The increased prevalence of antimicrobial resistant (AMR) infections is a significant global health threat, resulting in increased morbidity, mortality, and costs. The drivers of AMR are complex and potentially impacted by socioeconomic factors. We investigated the relationships between geographic and socioeconomic factors and AMR.Methods We collected select patient bacterial culture results from 2015 to 2020 from electronic health records (EHR) of two expansive healthcare systems within the Dallas-Fort Worth, TX (DFW) metropolitan area. Among individuals with EHR records who resided in the four most populus counties in DFW, culture data were aggregated. Case counts for each organism studied were standardized per 1,000 persons per area population. Using residential addresses, the cultures were geocoded and linked to socioeconomic index values. Spatial autocorrelation tests identified geographic clusters of high and low AMR organism prevalence and correlations with established socioeconomic indices.Results We found significant clusters of AMR organisms in areas with high levels of deprivation, as measured by the Area Deprivation Index (ADI). We found a significant spatial autocorrelation between ADI and the prevalence of AMR organisms, particularly for AmpC and MRSA with 14% and 13%, respectively, of the variability in prevalence rates being attributable to their relationship with the ADI values of the neighboring locations.Conclusions We found that areas with a high ADI are more likely to have higher rates of AMR organisms. Interventions that improve socioeconomic factors such as poverty, unemployment, decreased access to healthcare, crowding, and sanitation in these areas of high prevalence may reduce the spread of AMR.

Human infectious diseases are the second leading cause of death worldwide [1]. Staphylococcus aureus (S. aureus) is pathogenic bacteria causing various diseases, including pneumonia, skin and soft tissue infections, bacteremia, and endocarditis [1,2]. China Antimicrobial Resistance Surveillance System (CARSS) reported a 46% detection rate of S. aureus in 2020 [3]. The study showed that MRSA prevalence ranged from 0% to 73% at 19 sites in the Asia-Pacific region from 2000 to 2016 [3]. Recently, the rate of MRSA infection has been increasing sharply[4], posing a challenge to the health system in terms of difficult therapy, extended length of hospital stay, expanded health costs, and high mortality [4,5].

by M. Gabriela Cabanilla, Michael L. Bernauer, Liana M. Atallah, Matthew J. Briski, Jason Koury, Cecilia M. Thompson, Chelsea N. Rodriguez, Bernadette Jakeman, Thomas F. Byrd Background Methicillin-resistant Staphylococcus aureus (MRSA) is associated with high mortality rates. Despite antibiotic therapy, persistent bacteremia is challenging to treat. Combination therapy with ceftaroline has emerged as a potential treatment option; however, the optimal duration and clinical implications after bacteremia clearance are unknown. Methods This retrospective cohort study examined patients with high-grade or persistent MRSA bacteremia who were treated with ceftaroline combination therapy at the University of New Mexico Hospital between January 2014 and June 2021. Patients were categorized into short- (…

Gown and glove use as a component of ‘contact precautions’ was first recommended by the United States Healthcare Infection Control Practices Advisory Committee (HICPAC) in 1996 and remains widely adhered to today (1, 2). Despite a lack of randomised trial evidence in support of this practice, donning of gowns and gloves upon entry to the patient area (room or cubicle) continues to be ‘strongly recommended’ when the patient is infected or colonised with pathogens of epidemiological importance and the potential for contact transmission (3).

Abstract Background Environmental disinfection is essential for reducing spread of healthcare associated infections (HAIs). Previous studies report conflicting results regarding the effects of ultraviolet light (UV) in reducing infections. This trial evaluated the impact of adding pulsed xenon UV (PX-UV) to standard terminal cleaning in reducing environmentally-implicated HAIs (eiHAIs).Methods The LAMP trial was conducted in 2 hospitals (15 inpatient wards) utilizing a cluster randomized controlled, double-blinded, interventional crossover trial comparing standard terminal cleaning followed by either pulsed xenon ultraviolet (PX-UV) disinfection (intervention arm) or sham disinfection (control arm). The primary outcome was incidence of eiHAIs from clinical microbiology tests on the 4th day of stay or later or within 3 days after discharge from the study unit. EiHAIs included clinical cultures positive for vancomycin-resistant enterococci (VRE), extended spectrum beta-lactamase-producing Escherichia coli or Klebsiella pneumonia, methicillin-resistant Staphylococcus aureus (MRSA), and Acinetobacter baumannii, and stool PCR positive for Clostridiodes difficile.Findings Between May 18, 2017 to Jan 7, 2020, 25,732 patients were included, with an incidence of 601 eiHAI and 180,954 patient days. There was no difference in the rate of eiHAIs in the intervention and sham arms (3.49 vs 3.17 infections/1000 patient days respectively, RR 1.10 CI (0.94, 1.29, p= 0.23)). Study results were similar when stratified by eiHAI type, hospital, and unit type.Conclusion The LAMP study failed to demonstrate an effect of the addition of UV light disinfection following terminal cleaning on reductions in rates of eiHAIs. Further investigations targeting hospital environmental surfaces and the role of no touch technology to reduce HAIs are needed.

by Evan Jarman, Jordan Burgess, Ayushi Sharma, Kate Hayashigatani, Amar Singh, Paige Fox The complexity of chronic wounds creates difficulty in effective treatments, leading to prolonged care and significant morbidity. Additionally, these wounds are incredibly prone to bacterial biofilm development, further complicating treatment. The current standard treatment of colonized superficial wounds, debridement with intermittent systemic antibiotics, can lead to systemic side-effects and often fails to directly target the bacterial biofilm. Furthermore, standard of care dressings do not directly provide adequate antimicrobial properties. This study aims to assess the capacity of human-derived collagen hydrogel to provide sustained antibiotic release to disrupt bacterial biofilms and decrease bacterial load while maintaining host cell viability and scaffold integrity. Human collagen harvested from flexor tendons underwent processing to yield a gellable liquid, and subsequently was combined with varying concentrations of gentamicin (50–500 mg/L) or clindamycin (10–100 mg/L). The elution kinetics of antibiotics from the hydrogel were analyzed using liquid chromatography-mass spectrometry. The gel was used to topically treat Methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium perfringens in established Kirby-Bauer and Crystal Violet models to assess the efficacy of bacterial inhibition. 2D mammalian cell monolayers were topically treated, and cell death was quantified to assess cytotoxicity. Bacteria-enhanced in vitro scratch assays were treated with antibiotic-embedded hydrogel and imaged over time to assess cell death and mobility. Collagen hydrogel embedded with antibiotics (cHG+abx) demonstrated sustained antibiotic release for up to 48 hours with successful inhibition of both MRSA and C. perfringens biofilms, while remaining bioactive up to 72 hours. Administration of cHG+abx with antibiotic concentrations up to 100X minimum inhibitory concentration was found to be non-toxic and facilitated mammalian cell migration in an in vitro scratch model. Collagen hydrogel is a promising pharmaceutical delivery vehicle that allows for safe, precise bacterial targeting for effective bacterial inhibition in a pro-regenerative scaffold.

Abstract Background Overuse of antibiotics is a key driver of antimicrobial resistance (AMR) world-wide. Malawi continues to report rising cases of AMR among both in-patients and out-patients. We investigated antibiotic use and resistance patterns among patients with suspected first line antibiotic treatment failure at Rumphi District Hospital, Malawi. Methods We used a cross-sectional study design in which records of patients data on culture and antimicrobial sensitivity tests were extracted, alongside treatment history from 2019 to March, 2023, retrospectively. We also included findings for point prevalence survey (PPS) conducted within four hospital wards in June, 2022 by a well-trained multi-disciplinary team from within the hospital. The data was analyzed for antibiotic use, characterization of pathogens and their susceptibility patterns using Microsoft excel and STATA-14 software. Results A total of 85 patients’ data records were reviewed on antibiotics resistance pattern in which 54 (63.5%) were females. Patient antibiotic history captured indicated Metronidazole (23%), Gentamycin (20%) and Doxycycline (23%) as the most frequently used antibiotics among clients referred for microbiological investigations. Among locally available antibiotics with over 50% sensitivity were Chloramphenicol (61%), ciprofloxacin (55%), and ceftriaxone (54%). Penicillins were among antibiotics with highest resistance: ampicillin (100%), amoxyclav (90%), Piperacilin-tazobactam (63%). The majority of patients came from STI clinic and presented with genital discharges 44% (n = 39). Over 80% of the isolated N. gonorrhoeae exhibited a reduced susceptibility to gentamycin. Prevalence of Methicillin resistant staphylococcus Aureus (MRSA) was 46% and were mostly isolated from wound pus. Among 80 data records of the patients reviewed during PPS, Ceftriaxone (54.3%) and Metronidazole (23.3%) emerged as the most frequently used antibiotics in the wards which were prescribed empirically without a microbiological indication. Conclusion In this study setting, we observed high use of watch antibiotics along with problem of multi-drug resistant infections in patients experiencing clinical failure in a variety of clinical syndromes. The findings underline the need to revamp diagnostic microbiology to increase the uptake of antimicrobial susceptibility testing to guide specific prescriptions of broad-spectrum antibiotics in the watch list. …

Abstract Background Metagenomic next-generation sequencing (mNGS) has been increasingly applied in sepsis. We aimed to evaluate the diagnostic and therapeutic utility of mNGS of paired plasma and peritoneal drainage (PD) fluid samples in comparison to culture-based microbiological tests (CMTs) among critically ill patients with suspected acute intra-abdominal infections (IAIs). Methods We conducted a prospective study from October 2021 to December 2022 enrolling septic patients with suspected IAIs (n = 111). Pairwise CMTs and mNGS of plasma and PD fluid were sent for pathogen detection. The mNGS group underwent therapeutic regimen adjustment based on mNGS results for better treatment. The microbial community structure, clinical features, antibiotic use and prognoses of the patients were analyzed. Results Higher positivity rates were observed with mNGS versus CMTs for both PD fluid (90.0% vs. 48.3%, p 

Abstract Background The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased the incidence of community-onset MRSA infection. Respiratory tract infections caused by MRSA has been noted for their severity; however, repeated relapses that require extended antibiotic therapy are rare. Case presentation We report a case of relapsing bronchopneumonia caused by CA-MRSA in a 56-year-old man. The patient responded to antibiotics, but repeatedly relapsed after stopping treatment. MRSA was consistently isolated from airway specimens during each relapse. Extended oral antibiotic treatment with trimethoprim/sulfamethoxazole (TMP/SMX) for 6 months achieved infection control. Whole-genome sequencing of the isolated strain revealed that the causative agent was sequence type (ST)1/staphylococcal cassette chromosome mec (SCCmec) type IVa, a clone that is rapidly increasing in Japan. Discussion and conclusions This patient had an unusual course of MRSA bronchopneumonia with repeated relapses. Although the choice of antibiotics for long-term use in MRSA respiratory tract infections has not been well established, TMP/SMX was effective and well tolerated for long-term therapy in this case. The clinical course of infections related to the rapid emerging clone, ST1/SCCmec type IVa warrants further attention. …

Abstract Background The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased the incidence of community-onset MRSA infection. Respiratory tract infections caused by MRSA has been noted for their severity; however, repeated relapses that require extended antibiotic therapy are rare. Case presentation We report a case of relapsing bronchopneumonia caused by CA-MRSA in a 56-year-old man. The patient responded to antibiotics, but repeatedly relapsed after stopping treatment. MRSA was consistently isolated from airway specimens during each relapse. Extended oral antibiotic treatment with trimethoprim/sulfamethoxazole (TMP/SMX) for 6 months achieved infection control. Whole-genome sequencing of the isolated strain revealed that the causative agent was sequence type (ST)1/staphylococcal cassette chromosome mec (SCCmec) type IVa, a clone that is rapidly increasing in Japan. Discussion and conclusions This patient had an unusual course of MRSA bronchopneumonia with repeated relapses. Although the choice of antibiotics for long-term use in MRSA respiratory tract infections has not been well established, TMP/SMX was effective and well tolerated for long-term therapy in this case. The clinical course of infections related to the rapid emerging clone, ST1/SCCmec type IVa warrants further attention. …

To the Editor—We read with great interest the state-of-the-art review article by Minter et al, “Contemporary management of Staphylococcus aureus bacteremia—controversies in clinical practice” [1]. This is an excellent review of the literature and highly recommended reading for all infectious diseases clinicians. The purpose of our letter is to add some additional nuances in clinical practice that merit consideration by clinicians who treat Staphylococcus aureus bacteremia (SaB), particularly with methicillin-resistant Staphylococcus aureus (MRSA).

This study aims to evaluate two commercial broth microdilution (BMD) systems, E1-185-100 (Merlin) and FDANDPF (ThermoFisher) for dalbavancin susceptibility testing in comparison with reference broth microdilution assay.

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 is a globally disseminated MRSA lineage. Herein, we investigated whether MRSA ST45 isolates from cellulitis and from osteomyelitis display distinctive phenotypic and genomic characteristics.Methods A total of 15 MRSA ST45 isolates from cellulitis (CL-MRSAs; n = 6) or osteomyelitis (OM-MRSAs; n = 9) were collected in a Taiwan hospital. These MRSA ST45 isolates were characterized for their antimicrobial susceptibility, biofilm-forming ability, cellular infectivity in vitro, and pathogenicity in vivo. Four CL-MRSA and six OM-MRSA ST45 isolates were selected for whole-genome sequencing (WGS).Results Antibiotic resistance tests showed that all OM-MRSA ST45 strains, but not CL-MRSA ST45 strains, were resistant to ciprofloxacin, levofloxacin, gentamicin and doxycycline. Compared to the CL-MRSA ST45 isolates, the OM-MRSA ST45 isolates had stronger biofilm-forming ability and cellular infectivity, and caused more severe disease in mice. WGS analysis revealed that these OM-MRSA ST45 isolates carry multiple common mutations or polymorphisms in genes associated with antibiotic resistance and virulence. Moreover, the transposable elements IS256 and IS257R2 were found only in the OM-MRSA ST45 isolates.Conclusions The emergence and spread of the highly pathogenic and multidrug-resistant ST45 MRSAs identified from osteomyelitis may pose a serious threat on public health.

Abstract Background While there is a high burden of methicillin-resistant Staphylococcus aureus (MRSA) infections among pediatric patients, studies on the molecular epidemiology of MRSA infections in Korean children since the 2010s are lacking. This study aimed to investigate the molecular genotypes and clinical characteristics of MRSA isolates from children with MRSA bacteremia at Asan Medical Center Children’s Hospital from 2016 to 2021. Methods Clinical data were retrospectively reviewed, and the molecular types of MRSA were determined using multilocus sequence typing (MLST) and Staphylococcal cassette chromosome mec (SCCmec) typing. Results The overall methicillin resistance rate of S. aureus bacteremia was 44.8% (77/172); 49.5% in the period 2016–2018 (period 1) and 37.3% in the period 2019–2021 (period 2) (P = 0.116). Community-acquired infections accounted for only 3.9% of cases. The predominant ST group was ST72 group (67.6%), followed by ST5 group (18.9%) and ST1 group (5.4%). The proportion of ST5 was significantly lower in period 2 compared to period 1 (P = 0.02). Compared to the ST5 and ST1 groups, the ST72 group exhibited lower overall antibiotic resistance and multidrug-resistant (MDR) rates (12.0% [6/50] in ST72 group vs. 100.0% [14/14] in ST5 group vs. 50.0% [2/4] in ST1 group; P 

Globally, the isolation of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) harbouring both the Panton–Valentine leucocidin (PVL) and toxic shock syndrome toxin 1 (TSST-1) genes is rare. However, we encountered an outbreak of the ST22-PT clone exhibiting this phenotype in Japan. Notably, the TSST-1 gene was duplicated in most of the strains. This study aimed to elucidate the mechanisms underlying this gene duplication.

Abstract Background With the global increase in the older population, the proportion of those receiving care in long-term care facilities (LTCFs) has also been increasing. We assessed the epidemiology, antibiotic susceptibility, and colonization status of drug-resistant organisms in patients transferred from LTCFs. Methods We retrospectively reviewed the medical records of patients transferred from LTCFs between 2017 and 2022. The reasons for admission, antimicrobial susceptibility, and colonization rates of carbapenem-resistant Enterobacterales (CRE), methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Acinetobacter baumannii (CRAB) were recorded. We analyzed the susceptibility and colonization rates by year to identify trends. Results Of the 936 patients transferred from LTCFs, 54.3% were admitted to the intensive care unit and 12.5% died. The most common reason for admission was infection (n = 573, 61.2%), followed by gastrointestinal bleeding (n = 67, 7.2%) and cerebrovascular disorder (n = 65, 6.9%). A total of 452 Enterobacterales strains were isolated, and their susceptibility rates to ciprofloxacin and cefotaxime were 33.3% and 35.6%, respectively. A total of 54.9% were extended-spectrum beta-lactamase-producing strains, and 4.9% of them were carbapenem-resistant, both of which showed an increasing trend (P = 0.024 and P 

Abstract Background With the global increase in the older population, the proportion of those receiving care in long-term care facilities (LTCFs) has also been increasing. We assessed the epidemiology, antibiotic susceptibility, and colonization status of drug-resistant organisms in patients transferred from LTCFs. Methods We retrospectively reviewed the medical records of patients transferred from LTCFs between 2017 and 2022. The reasons for admission, antimicrobial susceptibility, and colonization rates of carbapenem-resistant Enterobacterales (CRE), methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Acinetobacter baumannii (CRAB) were recorded. We analyzed the susceptibility and colonization rates by year to identify trends. Results Of the 936 patients transferred from LTCFs, 54.3% were admitted to the intensive care unit and 12.5% died. The most common reason for admission was infection (n = 573, 61.2%), followed by gastrointestinal bleeding (n = 67, 7.2%) and cerebrovascular disorder (n = 65, 6.9%). A total of 452 Enterobacterales strains were isolated, and their susceptibility rates to ciprofloxacin and cefotaxime were 33.3% and 35.6%, respectively. A total of 54.9% were extended-spectrum beta-lactamase-producing strains, and 4.9% of them were carbapenem-resistant, both of which showed an increasing trend (P = 0.024 and P 

Antimicrobial Agents and Chemotherapy, Ahead of Print.

Abstract Aims We investigated the antibacterial efficacy of Umonium38 and Virkon® against Burkholderia pseudomallei, Escherichia coli, Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus (MRSA) up to 14 days following treatment. Methods and results Umonium38 was diluted to 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3%, tested against the bacterial strains at various contact times (15 min to 24 h), and incubated for up to 14 days. A minimum concentration of 0.5% Umonium38 with a contact time of 15 min effectively killed approximately 108 CFU/ml of all four bacterial species. No growth was observed on agar plates from day 0 until day 14 for all six concentrations. The bacteria were also inactivated by a 30-minute treatment time using Virkon® 1% solution. Conclusions Umonium38 effectively inactivates B. pseudomallei, E. coli, P. aeruginosa and MRSA at a concentration of ≥ 0.5% with a contact time of at least 15 min. The antimicrobial effect of Umonium38 remained for 14 days. …

Abstract Aims We investigated the antibacterial efficacy of Umonium38 and Virkon® against Burkholderia pseudomallei, Escherichia coli, Pseudomonas aeruginosa and Methicillin-Resistant Staphylococcus aureus (MRSA) up to 14 days following treatment. Methods and results Umonium38 was diluted to 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3%, tested against the bacterial strains at various contact times (15 min to 24 h), and incubated for up to 14 days. A minimum concentration of 0.5% Umonium38 with a contact time of 15 min effectively killed approximately 108 CFU/ml of all four bacterial species. No growth was observed on agar plates from day 0 until day 14 for all six concentrations. The bacteria were also inactivated by a 30-minute treatment time using Virkon® 1% solution. Conclusions Umonium38 effectively inactivates B. pseudomallei, E. coli, P. aeruginosa and MRSA at a concentration of ≥ 0.5% with a contact time of at least 15 min. The antimicrobial effect of Umonium38 remained for 14 days. …

Antimicrobial Agents and Chemotherapy, Ahead of Print.

Abstract 20–41% of the world\'s population is either transiently or permanently colonized by the Gram-positive bacterium, Staphylococcus aureus. In 2017, the CDC designated methicillin resistant S. aureus (MRSA) as a serious threat, reporting ∼300 000 cases of MRSA-associated hospitalizations annually, resulting in over 19 000 deaths, surpassing that of HIV in the United States. S. aureus is a proficient biofilm-forming organism, which rapidly acquires resistance to antibiotics, most commonly methicillin (MRSA).This review focuses on a large group of (>30) S. aureus adhesins, either surface-associated or secreted that are designed to specifically bind to 15 or more of the proteins that form key components of the human extracellular matrix (hECM). Importantly, this includes hECM proteins that are pivotal to the homeostasis of almost every tissue environment (collagen (skin), proteoglycans (lung), hemoglobin (blood), elastin, laminin, fibrinogen, fibronectin, and fibrin (multiple organs). These adhesins offer S. aureus the potential to establish an infection in every sterile tissue niche. These infections often endure repeated immune onslaught, developing into chronic, biofilm-associated conditions that are tolerant to ∼1000 times the clinically prescribed dose of antibiotics. Depending on the infection and the immune response, this allows S. aureus to seamlessly transition from colonizer to pathogen by subtly manipulating the host against itself while providing the time and stealth that it requires to establish and persist as a biofilm. This is a comprehensive discussion of the interaction between S. aureus biofilms and the hECM. We provide particular focus on the role of these interactions in pathogenesis and consequently the clinical implications for the prevention and treatment of S. aureus biofilm infections.

Abstract Background Equitable representation of members from historically marginalized groups is important in clinical trials, which inform standards of care. The goal of this study was to characterize the demographics and proportional subgroup reporting and representation of participants enrolled in randomized controlled trials (RCTs) of antibacterials used to treat Staphylococcus aureus infections.Methods We examined randomized controlled registrational and strategy trials published from 2000-2021 to determine the sex, race, and ethnicity of participants. Participation to incidence ratios (PIRs) were calculated by dividing the percentage of study participants in each demographic group by the percentage of the disease population in each group. Underrepresentation was defined as a PIR

Abstract Background Empyema necessitans (EN) is a rare condition characterized by pleural infection with pus spreading into adjacent soft tissues. Although Mycobacterium tuberculosis and Actinomyces israelii are common causative agents, methicillin-resistant Staphylococcus aureus (MRSA) is relatively rare, but it is associated with high mortality in empyema cases. We aimed to report a unique case of EN caused by MRSA and present a literature review to better understand this rare condition. Case presentation A 69-year-old man with a history of right ureteral stone presented with fever and left anterior thoracic pain. A physical examination revealed redness and swelling in the left thoracic region. Imaging studies confirmed EN with fluid accumulation around the sternocostal joint of the left first rib. MRSA was identified from blood and pleural fluid cultures. The patient received antimicrobial therapy, and a chest tube was inserted for drainage. Despite initial improvement, vertebral osteomyelitis was diagnosed on day 17. The antimicrobials were subsequently terminated after 6 weeks, but vertebral osteomyelitis recurred, and treatment was resumed and completed on day 215. Conclusion EN caused by MRSA is rare, and the literature review revealed 14 cases from human sources. Positive blood cultures were observed in 40% of cases, and metastatic infections were present in 30% of cases. Osteomyelitis was the most common type of metastatic lesion. All the patients underwent drainage. Patients with MRSA-associated EN frequently develop disseminated lesions and should therefore be carefully examined. Moreover, appropriate treatment with antibiotics and drainage is necessary for a good prognosis. Although the prognosis appeared to be favorable in our review, publication bias and treatment challenges for metastatic infections should be considered. …