Characteristics of Staphylococcus aureus Isolated From Clinical Specimens in a Tertiary Care Hospital, Kathmandu, Nepal

Abstract

Introduction: Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. mecA gene is considered one of the important virulence factors of S. aureus responsible for acquiring resistance against methicillin. The main objective of this study was to explore the prevalence, antibiotic susceptibility pattern, and mec A gene. Methods: A total of 39 isolates of S. aureus were isolated from 954 clinical specimens processed in Microbiology laboratory of Himal Hospital, Kathmandu. Antimicrobial susceptibility test (AST) was performed by Kirby-Bauer disc diffusion method using cefoxitin, and performed Polymerase Chain Reaction (PCR) for amplification of mecA gene in MRSA isolates. Results: Out of 954 clinical samples, (16.2%; 153/954) samples had bacterial growth. Among 153 culture positive isolates, 25.5% (39/153) were positive for S. aureus. Among 39 S. aureus (61.5%; 24/39) were multiple drug resistant (MDR). On AST, amoxicillin was detected as the least effective while vancomycin was the most effective. The prevalence of methicillin resistance was 46% (18/39) of which 72.2% (13/18) were positive for mecA gene in PCR assay. Conclusion: One in 4 culture positive isolates from the clinical specimens were S. aureus, of which almost two-thirds were MDR. Around half of the MDR showed MRSA and significant proportion of them were positive for mecA gene. This study concludes that the mecA gene is solely dependent for methicillin resistance in S. aureus but the presence of gene is not obligatory. PCR detection of the mecA gene is reliable, valid and can be suggested for the routine use in diagnostic laboratories.

Methicillin Resistant Staphylococcus aureus in Health Care Workers of a Tertiary Care Infectious Disease Hospital in Nepal

“…Similarly, AST of MRSA isolates showed resistance to most of the antibiotics used except carbapenems, vancomycin and gentamicin. Our fi ndings resonate well with some of other fi ndings reported earlier (Thapa et al 2020;Kandel et al 2020;Sah et al 2013;Belbase et al 2017;. However, in another study, ciprofl oxacin was effective against MRSA isolates (Shrestha 2013).…”

“…MRSA prevalence in present study is higher than some overseas fi ndings from Iran (5.3%) and Zambia (5.7%) but lower than Ethiopia (12.7%), Libya (19%), Egypt In the antimicrobial susceptibility assay, most of the isolates were susceptible to carbapenems and gentamicin. Higher susceptibility of S. aureus isolates towards these antibiotics was also reported in previous studies (Thapa et al 2020;Kandel et al 2020;Sah et al 2013) and augmented resistance to gentamicin was also reported in another studies (Thulunga et al 2015).…”

“…This could be due to the increased awareness, augmented infection controls in the health facility under the study. However, other intrinsic factors also need to be assessed in future studies which might have been competing and inhibiting the expression of mecA in MRSA isolates in large number of study fi ndings (Kandel et al 2020). Globally, a number of studies have documented the absence of mecA in MRSA isolates (Aziz et al 2014).…”

“…MRSA once confi ned to hospitals, health care environments and patients frequenting such facilities, now has become a serious problem for communities due to its emergence as a major cause of the community- which results the emergence of novel strains furthering the challenges in the fi ght with AMR (Thapa et al 2020). A number of studies are conducted in Nepal which have estimated the prevalence of MRSA ranging from 26.1% to 57.1% (Ansari et al 2014;Kumari et al 2008;Khanal and Jha 2010;Raut et al 2017;Bhomi et al 2016;Shahi et al 2018;Thapa et al 2020;Kandel et al 2020). Although there seems a large number of studies are based on MRSA but almost all studies are merely relied on the phenotypic detection.…”

Methicillin-Resistant Staphylococcus aureus (MRSA): Prevalence, Antimicrobial Susceptibility Pattern, and Detection of mecA Gene among Cardiac Patients from a Tertiary Care Heart Center in Kathmandu, Nepal

“…49 Globally and in Nepal, the prevalence of MRSA is heterogeneous with varying prevalence (past studies from Nepal: 15.4%-26.0%), 23,50 however, recent studies from Nepal have shown higher prevalence (26%-69%) indicating the rising trend over the years. 51,52 Most of the studies investigating MRSA in Nepal utilized just cefoxitin and oxacillin for screening. Compared to oxacillin, cefoxitin is a better drug to detect mecA gene in MRSA and is considered as a substitute marker.…”