Assessment of the last-resort antibiotics against Extended Spectrum Beta-Lactamase/carbapenemase and biofilm producer Klebsiella pneumoniae isolated from hospitalized patients in intensive care units (ICUs), Iran

Pneumonia caused by Klebsiella pneumoniae (K. pneumoniae) is considered one of the most common causes of hospital-acquired infections. We aimed 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 COVID-۱۹ patients. In the current study phenotypic and genotypic screening of ESBLs, AmpC beta-lactamases, and carbapenemase enzymes was investigated. the activity of tigecycline, azithromycin, and colistin against ESBL/carbapenemase producer K. pneumoniae. Also, assessment of the ability of biofilm formation was performed. Finally, virulence genes were detected by the PCR method. By phenotypic detection tests ۲۷ (۲۹.۶%) out of ۹۱ K. pneumoniae isolates were classified as ESBL/carbapenemase-producing K. pneumoniae strains. Also, molecular methods showed, all ۲۷ K. pneumoniae isolates harbored at least ۱ of the ESBL/carbapenemase-related genes. ESBL-associated genes (۱۹.۷% blaTEM, ۲۹.۶% blaSHV, and ۱۹.۷% blaCTX-M) were detected in ۹۱ K. pneumoniae isolates. Carbapenemase-related genes were detected in ۱۷.۵% of these isolates (blaOXA-۴۸-like ۱۵.۴%, and blaNDM۱ ۲.۱%). All of the ۲۷ selected isolates, exhibited biofilm formation ability. In this study, ۹۲.۵۹%, ۹۲.۵۹%, ۸۱.۴۸%, ۸۸.۸%, ۴۰.۷۴%, ۱۱.۱ %, ۲۲.۲۲%, ۱۸.۵%, ۱۴.۸۱% and ۳۳.۳۳% of the ESBL/carbapenemase producer K. pneumoniae isolates carried entB, mrkD, fimH, Irp۲, wcaG, mrkA, rmpA, iutA and magA genes, respectively. But iucA gene was not present in any of isolates. Tigecycline and colistin were more effective against these isolates. Multilocus sequence typing (MLST) results for four colistin-resistant isolates showed three different sequence types ST: ST۳۵۰۰, ST۲۷۳, and ۲ cases of ST۲۵۵۸. The rapid emergence and spread of colistin-resistant and Beta-lactamase producer K. pneumoniae has resulted in an alarming situation worldwide. 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.

کلیدواژه ها:

K. pneumoniae ، Carbapenem resistance ، Extended-spectrum beta-lactamases ، Iran