Burden of carbapenem-resistant Acinetobacter baumannii involved in ventilator-associated pneumonia

Objectives: Ventilator-associated pneumonia (VAP) is the most prevalent nosocomial infection of the intensive care unit (ICU) of any hospital, which accounts for more than 25% of all ICU infections. Among the Gram-negative bacilli, carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii are highlighted as “pathogens of concern” by the World Health Organization. Although carbapenems were formerly thought to be the backbone of treatment for life-threatening infections, these bacteria are rapidly acquiring resistance to carbapenems. Hence, the aim of this investigation was to identify and ascertain the prevalence of carbapenem-resistant A. baumannii from endotracheal aspirate (ETA) and bronchoalveolar lavage (BAL) samples, as well as the antibiotic susceptibility profile of this pathogen using VITEK 2 system. Material and Method: This prospective study was carried out from March 2023 to July 2024 at the Center for Interdisciplinary Biomedical Research, Adesh University, Bathinda. Two hundred suspected ETA and BAL samples were collected from the bacteriology lab of Adesh Hospital, Bathinda, Punjab. Identification and antibiotic susceptibility test for A. baumannii isolates were done by the VITEK 2 system. Results: Out of 200 VAP suspected endotracheal (ET)/BAL samples, a total 27 non-fermenters were isolated. Among 27 non-fermenters, A. baumannii was found in higher frequency (n = 17; 62.96%). In ET samples, its proportion was 66.66%, whereas in BAL samples, it was found to be only 33.33%. Among seventeen A. baumannii isolates, only two isolates (11.76%) were found susceptible to cefepime, ceftazidime, cefoperazone/sulbactam, piperacillin/tazobactam, meropenem, imipenem, gentamicin, ciprofloxacin, levofloxacin, and amikacin. Whereas, 88.23% isolates were resistant to all these drugs. Among all the antimicrobials, minocycline was found to be effective against A. baumannii as 82.35% isolates were found susceptible to it whereas, only 17.64% isolates were found to be resistant. Trimethoprim/sulfamethoxazole was effective against 47.05% isolates, whereas 52.94% isolates were resistant to it. Conclusion: Although in the present study, a low prevalence (8.5%) of A. baumannii causing VAP was seen due to effective infection control measures implemented by the infection control committee of the Adesh Hospital, Bathinda, but almost all strains were found to be carbapenem resistant, which is a worrisome situation. Thus, an effective infection control, including an interdisciplinary approach with microbiologists, is required to implement resistance surveillance in ICUs. The present study emphasizes the relevance of strictly adhering to “reserve antibiotics,” so carbapenems should be strictly avoided as an empirical treatment. Patients who are found positive for carbapenem-resistant pathogens should be isolated to avoid the dissemination. Antibiotic stewardship and awareness programs should be implemented by various stakeholders.