Prevalence and Susceptibility of Staphylococcus aureus Nasal Carriage Strains Isolated from Haemodialysis Patients

@#Introduction: Staphylococcus aureus is part of the normal human flora that can commonly be found on the skin and mucous membranes of the nasal area. However, in immunosuppressed patients such as those with kidney failures, colonization can potentially lead to infection. There is a concern of increasing antibiotic resistance in S. aureus. This study aimed to determine the prevalence of S. aureus nasal colonization and its antimicrobial susceptibility among haemodialysis-dependent populations. Methods: A cross-sectional study at the Nephrology Unit, Hospital Canselori Tuanku Mukhriz (HCTM) was conducted among haemodialysis-dependent patients between February 2017 to February 2018. Nasal swabs were obtained and cultured on mannitol salt agar. S. aureus isolates were identified by gram staining, tube coagulase and Deoxyribonuclease (DNase). Cefoxitin disc (30 µg) were used to identified the presence of MRSA (methicillin-resistance S. aureus). The S. aureus colonies were further tested against six antibiotics using Kirby Bauer disc diffusion. Result: A total of 134 patients were recruited. S. aureus isolates were detected from 27 patients (20.1%). All S. aureus were phenotypically identified as methicillin-sensitive S. aureus (MSSA) based on the cefoxitin disc. Teicoplanin and linezolid were the most effective with 100% susceptibility. S. aureus exhibited a high resistance rate towards erythromycin (29.6%). No MRSA was isolated in this study. Conclusion: This study highlighted the high prevalence of S. aureus nasal colonization in haemodialysis patients. Teicoplanin and linezolid were found to be the most effective antibiotics against isolated S. aureus.

Bactericidal antibiotic-phytochemical combinations against methicillin resistant Staphylococcus aureus

Methicillin resistant Staphylococcus aureus (MRSA) infection is a global concern nowadays. Due to its multi-drug resistant nature, treatment with conventional antibiotics does not assure desired clinical outcomes. Therefore, there is a need to find new compounds and/or alternative methods to get arsenal against the pathogen. Combination therapies using conventional antibiotics and phytochemicals fulfill both requirements. In this study, the efficacy of different phytochemicals in combination with selected antibiotics was tested against 12 strains of S. aureus (ATCC MRSA 43300, ATCC methicillin sensitive S. aureus or MSSA 29213 and 10 MRSA clinical strains collected from National University Hospital, Singapore). Out of the six phytochemicals used, tannic acid was synergistic with fusidic acid, minocycline, cefotaxime and rifampicin against most of strains tested and additive with ofloxacin and vancomycin. Quercetin showed synergism with minocycline, fusidic acid and rifampicin against most of the strains. Gallic acid ethyl ester showed additivity against all strains in combination with all antibiotics under investigation except with vancomycin where it showed indifference effect. Eugenol, menthone and caffeic acid showed indifference results against all strains in combination with all antibiotics. Interestingly, no antagonism was observed within these interactions. Based on the fractional inhibitory concentration indices, synergistic pairs were further examined by time-kill assays to confirm the accuracy and killing rate of the combinations over time. The two methods concurred with each other with 92% accuracy and the combinatory pairs were effective throughout the 24 hours of assay. The study suggests a possible incorporation of effective phytochemicals in combination therapies for MRSA infections.

Prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) Nasal carrier in Health Care Workers.

Methicillin resistance Staphylococcus aureus (MRSA) is an important nosocomial pathogen that causes severe morbidity and mortality worldwide. In recent years, nosocomial outbreaks of methicillin resistance Staphylococcus aureus (MRSA) has become a major infection control problem. Colonized employees are generally asymptomatic; they are a potential reservoir and disseminator of MRSA in hospitals. Nasal screening of health care workers (HCW) for MRSA is performed routinely in several countries, typically when more than one MRSA – colonized patient is identified in high risk ward, such as intensive care unit (ICU). This study was performed at PSG Hospitals to assess the prevalence of MRSA nasal colonization in health care workers and their sensitivity pattern. The prevalence of MRSA carriage among HCW’s was quite low (3.3%) in our institution. It has been recommended that, in case of epidemic in the hospital, all health care workers should be examined for MRSA colonization.