Molecular Identification of Carbapenem Resistance Acinetobacter baumannii causing Ventilator-Associated Pneumonia Isolated from Intensive Care Unit of Tertiary Care Hospital

Abstract

Ventilator-associated pneumonia (VAP) is a serious complication in critically ill patients, significantly increasing morbidity and mortality. One concerning organism behind VAP is Acinetobacter baumannii, a multidrug-resistant bacterium has ability to evade treatment, particularly with carbapenems, the last-line antibiotics. This is especially worrisome within the confines of Intensive Care Units (ICUs) of tertiary care hospitals, hubs for high-risk patients and potential reservoirs of antimicrobial resistance. This study focused on identifying carbapenem-resistant Acinetobacter baumannii using both phenotypic and genotypic methods. In 132 isolates of Acinetobacter baumannii, we observed 96% resistance to the cephalosporins while least resistance found to colistin and tigecycline. However, a concerning 51.5% of isolates exhibited carbapenem resistance. Phenotypically confirmation of carbapenem resistance detected in 47% isolates by Combined Disc Test and 51.5% isolates by Modified Hodge Test and E-test. Genotypic analysis with RT-PCR revealed a diverse array of resistance genes: blaIMP (33.82%), blaVIM (25%), blaOXA-Group (20.58%), and blaNDM (8.82%). These findings highlight the alarming prevalence of carbapenem-resistant Acinetobacter baumannii in healthcare settings.

Keywords

• ventilator-associated pneumonia
• acinetobacter baumannii
• multidrug resistance
• beta lactamase