Antimicrobial resistance in <em>Staphylococcus aureus</em>, Enterobacterales, and <em>Pseudomonas</em> spp. clinical isolates at a Teaching Hospital in Sri Lanka

Background: Antimicrobial resistance (AMR) is a signifi-cant global health issue in the 21st century, posing a serious threat to human health.Objectives: This study was to determine the burden and predictors of AMR and multidrug resistance (MDR) among bacterial pathogens isolated from specimens submitted to the diagnostic laboratory of a hospital in Sri Lanka.Methodology: This retrospective study used laboratory records of 1,204 clinical specimens submitted for bacterial culture submitted to the diagnostic laboratory of Neville Fernando Teaching Hospital in Sri Lanka for bacterial culture and sensitivity testing between October 2021 and May 2024. Records from specimens positive for Enterobacteriaceae, Staphylococcus aureus, or Pseudomonas spp. isolates were included for analysis.Results: Number of samples which yielded Gram negative Enterobacterales was 758 (62.95%). Of these 499 (65.83%) were ESBL and 59 (7.78%) were carba-penemase producers. Among the 214 participants, Staphylococcus aureus was isolated from 206 (96.26%) participants. This included 74 (35.92%) participants who were colonized with Methicillin Resistant Staphylococcus aureus (MRSA) isolates and Methicillin Sensitive Staphylococcus aureus (MSSA) 132 (64.07%). Among Pseudomonas spp. isolates, 29.48% were resistant to one or more aminoglycosides, 29.48% were resistant to a fluoroquinolone and only 8.54% were resistant to carbapenems.Conclusion: This study shows that there is a high level of microbial resistance in Sri Lanka. The high levels of extended-spectrum cephalosporin resistance and multi-drug resistance (MDR) among Enterobacterales observed in this study are of concern. However, the relatively low levels of methicillin-resistant Staphylococcus aureus (MRSA) and MDR S. aureus, as well as the very low levels of carbapenem resistance among Pseudomonas spp. isolates, are encouraging.