Bacteriological profile with phenotypic detection of MDR isolates in surgical site infections of Nishtar Hospital, Multan

Objective: To determine bacteriological profile with phenotypic detection of MDR isolates in surgical site infections. Materials and Methods: This cross-sectional descriptive study determined the frequency of bacteria causing surgical site infections in patients admitted at Nishtar Hospital, Multan. A total of 175 wound samples were collected and processed in the laboratory. All bacterial strains were characterized, and multidrug resistant strains were identified by an antibiotic susceptibility test. Moreover, modified carbapenem inactivation method, combine disc diffusion, and double disc synergy methods were employed to identify carbapenemases, metallo beta-lactamases, and extended spectrum beta-lactamases production among gram negative bacilli, respectively. Likewise, Cefoxitin-disc diffusion method was employed to identify S. aureus strains as methicillin-resistant staphylococcus aureus. Results: In this study, P. aeruginosa (40%), E. coli (19.4%), Proteus spp. (8.6%), K. pneumoniae (6.3%), Enterobacter (2.9%), and A. baumannii (2.2%) made up the majority of the detected Gram-Negative Bacilli, while S. aureus (20.6%) was the only isolated Gram-Positive Cocci. A significant proportion of Gram-Negative Bacilli showed resistance to amoxicillin/clavulanic acid, ampicillin, ceftriaxone, trimethoprim/sulfamethoxazole, ciprofloxacin, amikacin, piperacillin/tazobactam, and meropenem, while Gram Positive Cocci showed resistance to ampicillin, amoxicillin/clavulanic acid, cefoxitin, and ceftriaxone. In this study, among 139 identified Gram-Negative Bacilli, 111 (79.9%) strains were CP (+), 122 (87.8%) strains were MBL (+), and 62 (44.6%) strains were ESBL (+). Likewise, 36 isolated strains of S. aureus were analyzed, out of which 30 (83.3%) were Methicillin-Resistant Staphylococcus Aureus (+). Conclusion: our study will help in surveillance of resistance patterns of antibiotics and provide a cornerstone for the appropriate therapeutic strategy against multidrug-resistant infection. Keywords: Carbapenemases, ESBLs, MBLs, methicillin-resistant staphylococcus aureus, surgical site infections