Hospital-acquired Methicillin-resistant Staphylococcus Aureus Research Articles

Dynamical analysis of methicillin-resistant Staphylococcus aureus infection in North Cyprus with optimal control: prevalence and awareness

The number of Methicillin-resistant Staphylococcus aureus (MRSA) cases in communities and hospitals is on the rise worldwide. In this work, a nonlinear deterministic model for the dynamics of MRSA infection in society was developed to visualize the significance of awareness in interventions that could be applied in the prevention of transmission with and without optimal control. Positivity and uniqueness were verified for the proposed corruption model to identify the level of resolution of infection factors in society. Furthermore, how various parameters affect the reproductive number R0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${R}_{0}$$\\end{document} and sensitivity analysis of the proposed model was explored through mathematical techniques and figures. The global stability of model equilibria analysis was established by using Lyapunov functions with the first derivative test. A total of seven years of data gathered from a private hospital consisting of inpatients and outpatients of MRSA were used in this model for numerical simulations and for observing the dynamics of infection by using a non-standard finite difference (NSFD) scheme. When optimal control was applied as a second model, it was determined that increasing awareness of hand hygiene and wearing a mask were the key controlling measures to prevent the spread of community-acquired MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA). Lastly, it was concluded that both CA-MRSA and HA-MRSA cases are on the rise in the community, and increasing awareness concerning transmission is extremely significant in preventing further spread.

Panton-Valentine leucocidin gene in methicillin resistant Staphylococcus aureus isolated from tertiary care hospital in Nepal.

Methicillin-resistant Staphylococcus aureus (MRSA) expresses the Panton-Valentine leukocidin (PVL) virulence gene, which is associated with community and hospital-acquired severe MRSA infections. The objective of this study was to determine the prevalence and antibiotic susceptibility profile with a focus on the presence of the PVL gene among MRSA isolates in healthcare settings. A total of 1,207 clinical specimens and 304 hospital environment swabs were collected in a tertiary care hospital in Nepal, and investigated following basic microbiological techniques. S. aureus was confirmed with the coagulase test. An antibiotic susceptibility test (AST) was performed by the Kirby-Bauer method and screening for MRSA was carried out by the cefoxitin disc diffusion method guided by the Clinical and Laboratory Standards Institute (CLSI), 2020. DNA was extracted and used in a polymerase chain reaction (PCR) to detect mecA and PVL genes. Of the 1,511 samples, 45 (2.9%) S. aureus (23 clinical and 22 environmental) were isolated. Among them, 69.6% (16/23) and 27.3% (6/22) were MRSA in clinical and environmental isolates, respectively. Twelve (52.2%) clinical isolates and seven (31.8%) environmental isolates were multidrug resistant. The majority of isolates were susceptible to vancomycin and linezolid. The PVL gene was detected in 18.2% (n = 4/22) of the MRSA isolates, of which three were from clinical sources and one was from an environmental swab. The prevalence of MRSA, and PVL-producing S. aureus were higher in the hospital setting. Hence, immediate and urgent implementation of infection control and sanitation measures are needed in the hospital.

Synergistic bactericidal activity of a novel dual β-lactam combination against methicillin-resistant Staphylococcus aureus.

MRSA is a major cause of hospital-acquired and community-acquired infections. Treatment options for MRSA are limited because of the rapid development of β-lactam resistance. Combining antibiotics offers an affordable, time-saving, viable and efficient approach for developing novel antimicrobial therapies. Both amoxicillin and cefdinir are oral β-lactams with indications for a wide range of bacterial infections and mild side effects. This study aimed to investigate the in vitro and in vivo efficacy of combining these two β-lactams against MRSA strains. Fourteen representative prevalent MRSA strains with diverse sequence types (STs) were tested with a combination of amoxicillin and cefdinir, using chequerboard and time-kill assays. The Galleria mellonella larvae infection model was used to evaluate the in vivo efficacy of this dual combination against the community-acquired MRSA (CA-MRSA) strain USA300 and the hospital-acquired MRSA (HA-MRSA) strain COL. The chequerboard assay revealed a synergistic activity of the dual amoxicillin/cefdinir combination against all tested MRSA strains, with fractional inhibitory concentration index (FICI) values below 0.5 and at least a 4-fold reduction in the MICs of both antibiotics. Time-kill assays demonstrated synergistic bactericidal activity of this dual combination against the MRSA strain USA300 and strain COL. Moreover, in vivo studies showed that the administration of amoxicillin/cefdinir combination to G. mellonella larvae infected with MRSA strains significantly improved the survival rate up to 82%, which was comparable to the efficacy of vancomycin. In vitro and in vivo studies indicate that the dual combination of amoxicillin/cefdinir demonstrates a synergistic bactericidal efficacy against MRSA strains of various STs. Further research is needed to explore its potential as a treatment option for MRSA infections.

Prominent Classes of Antibiotics and their Mechanism of Resistance against Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a prominent pathogenic, antibiotic-resistant microorganism that contains a variety of virulent characteristics having the capacity to develop tolerance to several major classes of antibiotics. The ongoing creation of clones enhances this potential, transforming S. aureus into an “Anti-Infective.” MRSA has started to rise as a Hospital-Acquired MRSA, but due to evolution, new strains of MRSA have been discovered throughout the past several years. The new strains of MRSA as Community-Acquired MRSA, and Livestock-Associated MRSA are infecting the patients despite preexisting medical conditions, being as susceptible to any treatment. The continuous expansion of MRSA is still ongoing. The main goal of this article is to improve reading comprehension of MRSA by studying the prominent classes of antibiotics and their mechanism of resistance which are now susceptible or getting susceptible to the MRSA.

Detection of mecA Genes in Hospital-Acquired MRSA and SOSA Strains Associated with Biofilm Formation.

Methicillin-resistant (MR) Staphylococcus aureus (SA) and others, except for Staphylococcus aureus (SOSA), are common in healthcare-associated infections. SOSA encompass largely coagulase-negative staphylococci, including coagulase-positive staphylococcal species. Biofilm formation is encoded by the icaADBC operon and is involved in virulence. mecA encodes an additional penicillin-binding protein (PBP), PBP2a, that avoids the arrival of β-lactams at the target, found in the staphylococcal cassette chromosome mec (SCCmec). This work aims to detect mecA, the bap gene, the icaADBC operon, and types of SCCmec associated to biofilm in MRSA and SOSA strains. A total of 46% (37/80) of the strains were S. aureus, 44% (35/80) S. epidermidis, 5% (4/80) S. haemolyticus, 2.5% (2/80) S. hominis, 1.25% (1/80) S. intermedius, and 1.25% (1/80) S. saprophyticus. A total of 85% were MR, of which 95.5% showed mecA and 86.7% β-lactamase producers; thus, Staphylococcus may have more than one resistance mechanism. Healthcare-associated infection strains codified type I-III genes of SCCmec; types IV and V were associated to community-acquired strains (CA). Type II prevailed in MRSA mecA strains and type II and III in MRSOSA (methicillin-resistant staphylococci other than Staphylococcus aureus). The operon icaADBC was found in 24% of SA and 14% of SOSA; probably the arrangement of the operon, fork formation, and mutations influenced the variation. Methicillin resistance was mainly mediated by the mecA gene; however, there may be other mechanisms that also participate, since biofilm production is related to genes of the icaADBC operon and methicillin resistance was not associated with biofilm production. Therefore, it is necessary to strengthen surveillance to prevent the spread of these outbreaks both in the nosocomial environment and in the community.

Molecular Characteristics of Community-Acquired Methicillin-Resistant Staphylococcus aureus, Hospital-Acquired MRSA Isolates, and PVL in one of the Indian hospitals

Molecular Characteristics of Community-Acquired Methicillin-Resistant Staphylococcus aureus, Hospital-Acquired MRSA Isolates, and PVL in one of the Indian hospitals

Community-acquired Methicillin-resistant Staphylococcus Aureus Pneumonia: A Diagnostic Challenge

Even though methicillin-resistant Staphylococcus aureus (MRSA) is considered a source of nosocomial pneumonia, a few cases have likewise depicted instances of community-acquired pneumonia (CAP) among healthy individuals that were caused by MRSA. Mostly CA-MRSA causes skin and soft tissue infection but can be responsible for severe invasive infection with higher morbidity. Invasive CA-MRSA requires aggressive management to prevent complications. CA-MRSA strains are now recognized as distinct clonal entities that differ from traditional hospital-acquired MRSA (HA-MRSA) strains. The increasing prevalence of MRSA in the community is an important public health problem, which needs increased vigilance in the diagnosis and management of suspected and confirmed staphylococcal infections. We present an intense case of CAP brought about by MRSA with impending respiratory failure in a 19-year-old male, who presented with acute febrile illness with swelling over lips with no co-morbid and insignificant past medical history. Through this case, we intend to increase awareness among physicians about the growing role of CA-MRSA in the population; they should be meticulous in treating patients with CA-MRSA, and be aware of the complications of this disease and the appropriate empiric and target antibiotics regimen for such infections, whenever it is suspected, to enhance better clinical outcomes.

Recombination-mediated dissemination of Methicillin-resistant S. aureus clonal complex 1 in the Egyptian health care settings

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is a rapidly evolving pathogen that is frequently associated with outbreaks and sustained epidemics. This study investigated the population structure, resistome, virulome, and the correlation between antimicrobial resistance determinants with phenotypic resistance profiles of 36 representative hospital-acquired MRSA isolates recovered from hospital settings in Egypt.ResultsThe community-acquired MRSA lineage, clonal complex 1 (CC1) was the most frequently detected clone, followed by three other globally disseminated clones, CC121, CC8, and CC22. Most isolates carried SCCmec type V and more than half of isolates demonstrated multi-drug resistant phenotypes. Resistance to linezolid, a last resort antibiotic for treating multidrug resistant MRSA, was observed in 11.11% of the isolates belonging to different genetic backgrounds. Virulome analysis indicated that most isolates harboured a large pool of virulence factors and toxins. Genes encoding aureolysin, gamma hemolysins, and serine proteases were the most frequently detected virulence encoding genes. CC1 was observed to have a high pool of AMR resistance determinants including cfr, qacA, and qacB genes, which are involved in linezolid and quaternary ammonium compounds resistance, as well as high content of virulence-related genes, including both of the PVL toxin genes. Molecular clock analysis revealed that CC1 had the greatest frequency of recombination (compared to mutation) among the four major clones, supporting the role of horizontal gene transfer in modulating AMR and hypervirulence in this clone.ConclusionsThis pilot study provided evidence on the dissemination success of CA-MRSA clone CC1 among Egyptian hospitals. Co-detection of multiple AMR and virulence genes in this lineage pose a broad public health risk, with implications for successful treatment. The results of this study, together with other surveillance studies in Egypt, should be used to develop strategies for controlling MRSA infections in Egyptian health-care settings.

Discontinuation of contact precautions in patients with hospital-acquired MRSA and VRE infections during the COVID-19 pandemic: A multi-center experience.

Variations in the literature support the benefit of contact precautions for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) infections in the hospital setting. During personal protective equipment shortages throughout the COVID-19 pandemic, contact precautions were discontinued for MRSA and VRE-infected patients. Rates of hospital-acquired MRSA and VRE infections were compared before and after this intervention, along with hand hygiene proportions. Contact precaution discontinuation did not lead to an increase in hospital-acquired MRSA or VRE infections.

Limited reduction in Clostridioides difficile and Methicillin-Resistant Staphylococcus aureus with the use of an aerosolized hydrogen peroxide disinfection system in tertiary health care facilities in Alberta, Canada

Nonmanual room disinfection systems may reduce the transmission of infections. A variety of systems have emerged; however, a paucity of evidence exists to make an evidence-informed decision for the implementation of a specific system. Alberta Health Services assessed one of these systems. A quasi-experimental prepost design assessed an aerosolized hydrogen peroxide disinfection system on 6 units at 3 acute care facilities in Alberta. To assess clinical effectiveness an interrupted time-series analysis with Poisson distribution compared changes in hospital-acquired Clostridioides difficile infection (HA-CDI) and hospital-acquired Methicillin-resistant Staphylococcus aureus (HA-MRSA) between preintervention, intervention, and postintervention periods. To assess operational feasibility cleaning turnaround time, time to operate, and utilization were considered. A participatory research framework was used to understand the benefits and challenges of operationalization. Incidence rate ratio (IRR) of HA-CDI decreased by 25.7% on FMC-A and 6.9% on RAH-B. Following withdrawal, the IRR of HA-CDI continued to decrease. IRR of HA-MRSA decreased by 25.0% on RAH-B. Following withdrawal, the IRR of HA-MRSA continued to decrease. None of the results were statistically significant. The average time to operate was 3.2hours. Utilization was between 1.7% and 25.6%. Most staff reported benefits and challenges. None of the changes observed in HA-CDI and HA-MRSA after the introduction of the aerosolized hydrogen peroxide system were statistically significant. While most respondents reported multiple benefits and challenges in using the system, the core challenge was delays in inpatient admissions due to the time operate the system. Successful implementation of a nonmanual room disinfection system as an addition to standard cleaning and disinfection requires significant investment and must consider a variety of factors.

Methicillin-Resistant Staphylococcus aureus Colonization in Intensive Care and Burn Units: A Narrative Review.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common hospital-acquired pathogen and can cause a wide spectrum of infections. In recent years, MRSA has emerged as a significant public health concern, particularly in hospitals. Intensive care units (ICUs) and burn units are high-risk areas for hospital-acquired MRSA infections, which can lead to increased morbidity, mortality, and healthcare costs. MRSA exhibits resistance to multiple antibiotics and can cause serious infections, including but not limited to pneumonia, endocarditis, and cutaneous infections, particularly in patients with burn injuries. The prevention and effective management of MRSA infections in both burn patients and those in ICUs is crucial, with strategies like isolation, regular disinfection, and prophylactic intranasal mupirocin. Early diagnosis of MRSA infection and isolation of patients is vital to prevent the spread of MRSA. Implementation of prevention strategies faces many challenges, such as cost, and the most successful infection management practices are still debated. This review has highlighted the substantial concern of MRSA colonization in intensive care and burn units. MRSA poses a significant risk to vulnerable patients, influenced by factors such as compromised immunity and invasive procedures. The prevalence of MRSA colonization varies, influenced by regional factors and infection control practices. Combating MRSA requires a multifaceted approach, including stringent infection control measures and education for healthcare workers and patients. As we move forward, continued research and cooperation are essential to reduce the burden of MRSA in these critical care settings.

Molecular Detection of Hospital-Acquired Methicillin-Resistant Staphylococcusaureus Isolated From Teaching Hospitals in Damascus, Syria

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an established pathogen responsible for hospital-acquired infections (HAIs). Accurate MRSA diagnosis is of paramount importance to facilitate early and effective treatment and to manage its transmission effectively. The primary objective of our study was to determine the precise prevalence of hospital-acquired MRSA (HA-MRSA) in select teaching hospitals in Damascus by detecting the presence of the mecA gene. Methods: One hundred Staphylococcus aureus isolates were collected from various clinical specimens obtained from inpatients admitted to three major teaching hospitals in Damascus, Syria, including Al-Moussat, Al-Assad, and Tishreen Military Hospitals. These patients met the established criteria for HAIs. The isolates were collected between December 2021 and August 2022. Genus and species confirmation were conducted via polymerase chain reaction (PCR), employing the 16SrDNA gene specific to the Staphylococcus genus and the nuc gene specific to S. aureus. Methicillin resistance was assessed using cefoxitin disc diffusion (CDD) in accordance with Clinical and Laboratory Standards Institute (CLSI) recommendations. The presence of the mecA gene was also detected through PCR. Results: Out of the collected isolates, 67% exhibited resistance to cefoxitin, as determined by the CDD, while 66% were found to be positive for the mecA gene. CDD demonstrated a sensitivity of 100% and a specificity of 97%. Conclusion: This investigation revealed a notably high incidence of HA-MRSA infections within the teaching hospitals under scrutiny. The CDD method displayed significant sensitivity and specificity, making it a dependable alternative to the mecA PCR for MRSA detection. This finding holds substantial importance for the effective implementation of infection control initiatives and strategies aimed at eradicating MRSA and curtailing its spread within our hospital facilities.

Surveillance of methicillin-resistant Staphylococcus aureus infections obtained from pus sample: A comparison of community- and hospital-acquired infections

Abstract Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common causes of healthcare-associated infections. Recently, the prevalence of community-associated MRSA (CA-MRSA) is increasing affecting individuals with no known risk factors or health-care exposure, blurring the differences between the two. With changing epidemiology of an organism having a natural tendency of fast-developing resistance, MRSA infections need active ongoing surveillance, for effective implementation of appropriate treatment and preventive strategies. Patients and Methods: This was a prospective, observational study conducted in various inpatient departments of a tertiary care teaching hospital in Gujarat, India. MRSA infections were classified as community-acquired-MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA) based on the US CDC 2010 definition. Clinical and epidemiological profile as well as antibiotic sensitivity was assessed in both the groups. An unpaired t-test or Fisher’s exact test was applied to find the difference between the two groups. Results: MRSA isolation rate was 1.42% (60/4212). Ninety percentage of the isolates were multidrug-resistant (MDR), with three being vancomycin-resistant/intermediate. The total duration of hospitalization, number of antimicrobials used after isolation, and duration of therapy were higher in HA-MRSA compared to the CA-MRSA group. The treatment outcome was successful in 86.6% of patients. Conclusion: There is an increasing prevalence of CA-MRSA in the community with the majority of isolates being MDR. These data are alarming and indicate an urgent need for the implementation of strategies directed toward the effective use of appropriate antimicrobials as well as the improvement of hygiene practices in the hospital as well as the community.

Community-acquired and healthcare-associated Staphylococcus aureus infections in a pediatric hospital in southern Brazil over 8 years: how common is MRSA?

Both healthcare-associated and community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are relevant in children. The objective of our study was to evaluate their impact in a pediatric hospital in southern Brazil. Data from patients under 18 years of age with S. aureus infections between January 2013 and December 2020 were retrospectively analyzed. Data were collected regarding infection site, infection type (community-acquired or healthcare-associated), susceptibility to oxacillin [methicillin-susceptible S. aureus (MSSA) or MRSA] and other antimicrobials. We analyzed the evolution of the susceptibility rates for the isolates over this period. A total of 563 patients were included, among whom the prevalences of community- and hospital-acquired MRSA infections were 46.1% and 8.1%, respectively. No significant change occurred in these prevalences over the study period. In community-acquired infections, MSSA was significantly more associated with osteoarticular infections and MRSA was more associated with respiratory and intra-abdominal infections. In healthcare-associated infections, there was an association between MSSA and primary bloodstream infections and between MRSA, skin/soft tissue infections, and respiratory infections. Community-acquired MRSA were highly susceptible to trimethoprim-sulfamethoxazole (96.1%), clindamycin (88.4%), and doxycycline (99.0%). Our study draws attention to the high rates of MRSA in community-acquired staphylococcal infections in this population, indicating a need to review initial protocols for severe staphylococcal infections according to local epidemiology.

Dissemination Pattern of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus and Community-Acquired MRSA Isolates from Malaysian Hospitals: A Review from a Molecular Perspective.

The global emergence of methicillin-resistant Staphylococcus aureus (MRSA) that unsusceptible to a wide selection of antimicrobial agents and any newly introduced antimicrobial over the past decades has triggered more extensive holistic measures to put an end to this situation. Molecular surveillance of MRSA clones is important to understand their evolutionary dynamics for investigating outbreaks, propagating precautionary measures, as well as planning for appropriate treatment. This review includes peer-reviewed reports on the molecular characterisation of clinical Staphylococcus aureus isolates within Malaysian hospitals from year 2008 to 2020. This work highlights the molecular clones of hospital-acquired MRSA (HA-MRSA) and community-acquired MRSA (CA-MRSA) isolates from Malaysian hospitals, with description on their ever-changing pattern. Among HA-MRSA, the ST22-t032-SCCmec IV MRSA clone was reported to supplant the previous dominating clone, ST239-t037-SCCmec III. Meanwhile, ST30, ST772, ST6 and ST22 were repeatedly detected in CA-MRSA, however, none of the strains became predominant. Future in-depth study on molecular epidemiology of MRSA clone is essential for the investigation of the extent of the clonal shift, especially in Malaysia.

Increase in the frequency of community-acquired methicillin-resistant Staphylococcus aureus clones among inpatients of acute care hospitals in the Kyoto and Shiga regions, Japan

BackgroundSpecific epidemic clones of hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) are responsible for the worldwide spread of MRSA. However, in recent years, the isolation of community-acquired MRSA (CA-MRSA) clones has been increasing. We investigated the latest molecular epidemiology trends of HA-MRSA and CA-MRSA clones in the Kyoto and Shiga regions, Japan. Materials and methodsAll nonduplicate MRSA isolates obtained from the clinical specimens of inpatients at four acute care hospitals in the Kyoto and Shiga regions between 2014 and 2019 were typed using the PCR-based open reading frame typing (POT) method. CA-MRSA and HA-MRSA were classified according to the POT1 values. We performed whole-genome sequencing analysis for representative isolates displaying common POT types. ResultsA total of 2413 isolates were included in the study, comprising 1730 nosocomial and 683 nonnosocomial isolates. The rates of HA-MRSA decreased from 50.2% in 2014 to 19.0% in 2019, while those of CA-MRSA increased from 44.7% to 76.4% (p < 0.001). Isolates belonging to the most common 10 POT types (CA-MRSA, n = 6; HA-MRSA, n = 4) accounted for 42% of the isolates studied and were obtained from 3 or more hospitals. Whole-genome sequencing analysis showed that the common CA-MRSA isolates with POT types 106-137-80, 106-9-80, 106-9-2, and 106-137-2, those with POT types 106-183-37 and 106-129-5, and HA-MRSA isolates with POT types 93-191-103, 93-157-127, 93-137-103, and 93-223-111 belonged to ST8-SCCmecIV, ST1-SCCmecIV, and ST764-SCCmecII, respectively. ConclusionA recent clonal shift from HA-MRSA to CA-MRSA occurred, and specific regional clones were prevalent among inpatients in the Kyoto and Shiga regions.

Occurrence of Staphylococcus aureus in milk and antibacterial properties of some herbal extracts on milk and hospital-acquired strains

Staphylococcus aureus is a remarkable infectious agent, and with the development of antibiotic resistance by S. aureus, finding new, effective, and safe alternative therapeutic options in animals and humans is crucially demanded. In this study, the occurrence of S. aureus was explored by collecting nonmastitis bovine milk samples first, and then the effects of herbal extracts on methicillinresistant S. aureus (MRSA) strains isolated from cow's milk and humans in the hospitals were investigated. The occurrences of S. aureus in bovine raw milk samples were 13.4%. All raw milk S. aureus isolates were fully susceptible to cefoxitin, ceftiofur, penicillin G, and enrofloxacin. However, resistance was recorded for methicillin, streptomycin, tylosin, and sulfamethoxazole-trimethoprim. The most antibacterial resistance was recorded for oxytetracycline with 40% (intermediate resistance) and 15% (full resistance) respectively. The hospital-acquired S. aureus isolates were entirely resistant to methicillin and penicillin and were susceptible to some antibiotics. Sulfamethoxazole-trimethoprim was the most effective antibiotic with 83.4%. The antimicrobial activities of five medicinal herbs against raw milk S. aureus and hospital-acquired S. aureus isolates were assessed with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The findings affirmed that Rosmarinus officinalis and Nigella sativa acted as potent antibacterial agents on S. aureus strain obtained for nonmastitis bovine raw milk and hospital-acquired MRSA strains. The efficiency of these herbs against S. aureus isolates indicates their applicability as an antibacterial agent for alternative therapy in dairy products and human health and provokes further investigations in this area.

Characterisation of Methicillin-Resistant Staphylococcus aureus from Alexandria, Egypt.

The present study aims to characterise clinical MRSA isolates from a tertiary care centre in Egypt's second-largest city, Alexandria. Thirty isolates collected in 2020 were genotypically characterised by microarray to detect their resistance and virulence genes and assign them to clonal complexes (CC) and strains. Isolates belonged to 11 different CCs and 14 different strains. CC15-MRSA-[V+fus] (n = 6), CC1-MRSA-[V+fus+tir+ccrA/B-1] (PVL+) (n = 5) as well as CC1-MRSA-[V+fus+tir+ccrA/B-1] and CC1153-MRSA-[V+fus] (PVL+) (both with n = 3) were the most common strains. Most isolates (83%) harboured variant or composite SCCmec V or VI elements that included the fusidic acid resistance gene fusC. The SCCmec [V+fus+tir+ccrA/B-1] element of one of the CC1 isolates was sequenced, revealing a presence not only of fusC but also of blaZ, aacA-aphD and other resistance genes. PVL genes were also common (40%). The hospital-acquired MRSA CC239-III strain was only found twice. A comparison to data from a study on strains collected in 2015 (Montelongo et al., 2022) showed an increase in fusC and PVL carriage and a decreasing prevalence of the CC239 strain. These observations indicate a diffusion of community-acquired strains into hospital settings. The beta-lactam use in hospitals and the widespread fusidic acid consumption in the community might pose a selective pressure that favours MRSA strains with composite SCCmec elements comprising mecA and fusC. This is an unsettling trend, but more MRSA typing data from Egypt are required.

Community-acquired Methicillin-resistant Staphylococcus aureus Pneumonia and Parapneumonic Effusion in a Male Patient with Diabetes: A Case Report

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a primary health concern. They are commonly differentiated as hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections, based on their epidemiology, susceptibility findings, and molecular typing patterns. Therefore, appropriate contact precautions and isolation measures should be implemented. CA-MRSA mostly causes skin and soft-tissue infections, but the probability and incidence of it causing sepsis and invasive infections have increased dramatically in recent years. In this study, we report a case of CA-MRSA pneumonia with pan-pneumonic effusion in a 59-year-old male diabetic patient with preexisting comorbidities such as diabetic ketoacidosis and non-ST elevated myocardial infarction. The early reporting of the organism’s identity and its antimicrobial susceptibility, as well as timely initiation of antibiotic therapy, aided in the successful management and cure of the patient.

Phenotypic and Genotypic Characterization of Macrolide, Lincosamide and Streptogramin B Resistance among Clinical Methicillin-Resistant Staphylococcus aureus Isolates in Chile.

Macrolides, lincosamides, and type B streptogramins (MLSB) are important therapeutic options to treat methicillin-resistant Staphylococcus aureus (MRSA) infections; however, resistance to these antibiotics has been emerging. In Chile, data on the MLSB resistance phenotypes are scarce in both community-(CA) and hospital-acquired (HA) MRSA isolates. Antimicrobial susceptibility to MLSB was determined for sixty-eight non-repetitive isolates of each HA-(32) and CA-MRSA (36). Detection of SCCmec elements, ermA, ermB, ermC, and msrA genes was performed by PCR. The predominant clones were SCCmec I-ST5 (HA-MRSA) and type IVc-ST8 (CA-MRSA). Most of the HA-MRSA isolates (97%) showed resistance to clindamycin, erythromycin, azithromycin, and clarithromycin. Among CA-MRSA isolates, 28% were resistant to erythromycin, azithromycin, and 25% to clarithromycin. All isolates were susceptible to linezolid, vancomycin, daptomycin and trimethoprim/sulfamethoxazole, and over 97% to rifampicin. The ermA gene was amplified in 88% of HA-MRSA and 17% of CA-MRSA isolates (p < 0.001). The ermC gene was detected in 6% of HA-SARM and none of CA-SARM isolates, whereas the msrA gene was only amplified in 22% of CA-MRSA (p < 0.005). Our results demonstrate the prevalence of the cMLSB resistance phenotype in all HA-MRSA isolates in Chile, with the ermA being the predominant gene identified among these isolates.