Carbapenem-Resistant Complex Isolates Carrying and in Ventilator-Associated Pneumonia Patients and Contaminated Ventilator Tubing.

Ventilator-associated pneumonia (VAP) represents an important nosocomial infection, frequently encountered in intensive care unit (ICU) settings which results in prolonged hospitals stays. The nosocomial infections caused by complex (BCC) bacteria pose a significant challenge in healthcare settings owing to their intrinsic resistance to many antibiotics. This study investigates the antimicrobial susceptibility patterns and mechanisms of carbapenem resistance among BCC bacteria from VAP patients and the ventilator tubing. The blood and respiratory specimens from patients diagnosed with VAP were collected. In addition, the ventilators were also screened for the presence of BCC bacteria. The susceptibility profiling of BCC isolates was performed against the various antimicrobial agents, and screening for acquired beta-lactamase enzymes was conducted by polymerase chain reaction. Out of the total 134 patients with BCC-associated VAP, , , and was 68.7% ( = 92), 18.7% ( = 25), and 12.7% ( = 17). Overall, the BCC isolates showed varying susceptibility to different antibiotics: 76.9% were susceptible to chloramphenicol, 76.1% to minocycline, 69.4% to meropenem, 60.4% to ceftazidime, 51.5% to trimethoprim-sulfamethoxazole, and 50% to levofloxacin. Resistance to ceftazidime (51/92, 55.4%) and meropenem (36/92, 39.1%) was exclusively observed in isolates, and all isolates of and were found to be susceptible to both beta-lactam drugs. Among the 134 clinical isolates, 15 were found to harbor the variants, that is, and . All carbapenem-resistant isolates from the ventilator tubing were identified as and were found to harbor either the or the variants. The observed increase in resistance and the emergence of acquired beta-lactamases among BCC isolates highlight a concerning trend that could potentially lead to serious outbreaks.