Acinetobacter baumannii Co-Resistant to Extended Spectrum Beta-Lactamases and Carbapenemases in Six Peruvian Hospital Centers

Objectives: The aim of this study was to describe the phenotypic and molecular characteristics of Acinetobacter baumannii isolates carrying resistance genes to beta-lactams and carbapenems in six Peruvian public hospital centers. Materials and methods: The susceptibility of bacterial isolates was determined using the automated MicroScan system, with interpretation according to the M100 S30 CLSI 2020. Resistance genes were identified by conventional polymerase chain reaction (PCR), and PCR products were visualized by 1% agarose gel electrophoresis. Results: Nine strains (TRU1, PM1, PM2, CUS1, CUS2, CUS3, CAL1, CAL2 and CAL3) out of a total of 21 strains in the study were reactivated, showing resistance of 77.8% to imipenem, ciprofloxacin and cefepime, followed by 66.7% resistance to meropenem and ceftazidime, indicating marked multidrug resistance. In addition, the detection of the group A beta-lactamase genes blaCTX-M and blaTEM was confirmed, showing co-resistance in strains CUS1, CUS2 and CUS3, despite their unusual presence in this pathogen, also determined by the presence of the group D carbapenemase blaOXA in strain CUS3, the only strain to show co-resistance of the three groups. Conclusion: The prevalence of Acinetobacter baumannii resistant to extended-spectrum beta-lactamases and carbapenemases in Peruvian public centers represents a critical challenge for the treatment of infections. Rigorous surveillance, infection control strategies, and the development of alternative therapies are urgently needed to address this growing bacterial resistance.