Abstract
Pneumonia caused by Klebsiella pneumoniae (K. pneumoniae) is regarded as one of the most prevalent etiologies of nosocomial infections. The objective of this study was to investigate the activity of tigecycline, azithromycin, and colistin against K. pneumoniae isolated from bronchoalveolar lavage (BAL) samples of suspected cases of ventilator-associated pneumonia (VAP) in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The present study investigates the activity of tigecycline, azithromycin, and colistin against ESBL/carbapenemase-producing K. pneumoniae. The investigation encompasses the phenotypic and genotypic screening of ESBLs, AmpC beta-lactamases, and carbapenemase enzymes. Furthermore, an evaluation was conducted to ascertain the capacity of the biofilm to form. Consequently, the presence of virulence genes was identified through the implementation of a polymerase chain reaction (PCR) method. The utilization of phenotypic detection tests resulted in the categorization of 27 (29.6%) out of 91 K. pneumoniae isolates as ESBL/carbapenemase-producing K. pneumoniae strains. Furthermore, molecular methods revealed that all 27 K. pneumoniae isolates possessed at least one of the ESBL/carbapenemase-related genes. ESBL-associated genes were detected in 91 K. pneumoniae isolates, including 19.7% blaTEM, 29.6% blaSHV, and 19.7% blaCTX-M. Carbapenemase-related genes were identified in 17.5% of the isolates, including blaOXA-48-like (15.4%) and blaNDM1 (2.1%). The investigation revealed that all 27 of the isolates demonstrated the capacity to form biofilms. In this study, the prevalence of specific genes among ESBL/carbapenemase producer K. pneumoniae isolates was investigated. The genes analyzed included entB, mrkD, fimH, Irp2, wcaG, mrkA, rmpA, iutA, and magA. The results showed that 92.59%, 92.59%, 81.48%, 88.8%, 40.74%, 11.1%, 22.22%, 18.5%, 14.81%, and 33.33% of the isolates carried entB, mrkD, fimH, Irp2, wcaG, mrkA, rmpA, iutA, and magA genes, respectively. However, the iucA gene was not detected in any of the isolates examined. Tigecycline and colistin demonstrated higher efficacy against these isolates. Multilocus sequence typing (MLST) results for four colistin-resistant isolates revealed three distinct sequence types (ST): ST3500, ST273, and two cases of ST2558. The rapid emergence and subsequent dissemination of colistin-resistant and Beta-lactamase-producing K. pneumoniae has led to a worrisome global situation. The effective antimicrobial activity of tigecycline against K. pneumoniae that produce these enzymes may be efficient in hospitalized patients in ICUs with suspected cases of VAP.