Detection ofβ-Lactamases and Outer Membrane Porins amongKlebsiella pneumoniaeStrains Isolated in Iran

Abstract

This descriptive study was accomplished on 83 K. pneumoniae strains isolated from two hospitals in Tehran, Iran. Antibiotic susceptibility tests were performed by disc diffusion and broth microdilution methods. ESBLs, MBL, Amp-C, and KPC producing strains were detected by phenotypic confirmatory test, combination disk diffusion test (CDDT), Amp-C detection kit, and modified Hodge test, respectively. OXA-48, NDM-1, and CTX-M-15 genes were detected by PCR and sequencing methods. The outer membrane porins such as OmpK35 and OmpK36 were analysed by SDS-PAGE, PCR, and sequencing methods. From 83 K. pneumoniae isolates, 48 (57.5%), 3 (3.5%), 23 (28%), and 5 (6%) were ESBL, MBL, Amp-C, and KPC positive, respectively. The CTX-M-15 gene was detected in 30 (62.5%) and OXA-48 gene was found in 2 (4.1%) of the 48 ESBL-producing isolates. Two isolates harboured both OXA-48 and CTX-M-15; NDM-1 gene was not detected in this study. Outer membrane porin, OmpK35, was detected in 30 (62.5%) of 48 ESBL-producing isolates while OmpK36 was found in 35 (72.91%) of 48 ESBL-producing isolates. In this study, fosfomycin and tigecycline were more effective than other antibiotics. The high prevalence of β-lactamase-producing K. pneumoniae detected in this study is of great concern, which requires infection control measures including antibacterial management and identification of β-lactamases-producing isolates.

Study of <i>OmpK</i>35 and <i>OmpK</i>36 Expression in Carbapenem Resistant ESBL Producing Clinical Isolates of <i>Klebsiella pneumoniae</i>

“…These results were similar to previous studies by Hashemi et al [28], Ma et al [29], Ruiz [30] and Findlay et al [31] who also reported defects in OmpK35 and/or OmpK36 production in CR-KP isolates.…”

The emergence of blaOXA-48 and blaNDM among ESBL-producing Klebsiella pneumoniae in clinical isolates of a tertiary hospital in Iran

“…The first report of OXA-48producing K. pneumoniae strains in Iran was presented by Azimi et al [27]. In two separate studies conducted in Tehran hospitals (capital of Iran), the prevalence of bla OXA-48 among CRKP isolates was reported as 96.4% [27] and 4.1% [28]. Another study in southwestern Iran showed that 6.9% of CRKP isolates were positive for bla OXA-48 [29].…”

The threat of carbapenem-resistant gram-negative bacteria in a Middle East region

“…OmpK and carO genes that regulate expression of mutated efflux pump were detected in Hashemi et al and Pajand et al studies, respectively. 83 , 93 In another study, efflux pump’s activity and mutations in porins were investigated. 112 These results can expand the view about true mechanisms of resistance to carbapenems in developing countries.…”