Journal of Global Antimicrobial Resistance (Dec 2024)
Multidrug-resistant bacteria in surgical intensive care units
Abstract
Background and aim: The most important multidrug-resistant (MDR) bacteria are extended-spectrum β-lactamase (ESBL) and carbapenem-resistant Enterobacterales (CRE), Acinetobacter baumannii (CRAB), Pseudomonas aeruginosa (CRPE), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp (VRE). We evaluated the MDR bacteria in surgical ICUs in the tertiary hospital in Croatia. MATERIAL AND METHODS: The antibiotic susceptibility testing was performed by disk-diffusion and broth dilution method. Double disk synergy test and inhibitor based test with clavulanic acid were applied to screen for ESBLs. Transferability of resistance traits was determined by conjugation. The nature of ESBL, carbapenemases, and fluoroquinolone resistance determinants was investigated by PCR. RESULTS: 119 MDR isolates were analysed: 41 Klebsiella pneumoniae, 38 Acinetobacter bambini, five Pseudomonas aeruginosa, four Proteus. mirabilis, three Escherichia coli, two Enterobacter cloacae, and thirteen MRSA and VRE, respectively.Phenotypic tests were positive in 37 K. pneumoniae and all E. cloacae and E. coli isolates indicating production of an ESBL. Hodge test and CIM were positive in all but one strain, consistent with the carbapenemase production. Ertapenem resistance was transferable from 12 isolates positive for OXA-48 carbapenemase. PCR detected OXA-48 carbapenemase carried by IncL plasmid, in 34 K. pneumoniae, and one E. cloacae and E. coli isolate respectively, and NDM in three K. pneumoniae isolates. OXA-48 positive isolates coharboured ESBLs belonging to CTX-M family. All A. baumannii isolates tested positive for OXA-23 carbapenemase, whereas four P. aeruginosa produced VIM-2. CONCLUSIONS: OXA-48 was the dominant resistance trait among K. pneumoniae isolates, while OXA-23 was the only carbapenemase among A. baumannii isolates.
