Multicentre study of the main carbapenem resistance mechanisms in important members of the Enterobacteriaceae family in Iran

Abstract

Resistance to carbapenems has been increasingly reported from the Enterobacteriaceae family, with different mechanisms in different geographic parts of the world. This study investigated the mechanisms of carbapenem resistance in Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. carried out as a multicentre study ( n = 10). All third-generation cephalosporin-resistant E. coli, K. pneumoniae and Enterobacter spp. that had been recovered from the selected provinces were included. Modified Hodge test and Carba NP test were done as a phenotypical method for detection of carbapenemase; the most common carbapenemase was detected by PCR. We evaluated the presence of an active efflux pump by using cyanide 3-chlorophenylhydrazone. Overexpression of AcrA/B and presence of OqxAB was detected by real-time PCR and conventional PCR respectively. Microorganisms in this study included 58 E. coli , 95 K. pneumoniae and 60 Enterobacter spp. Modified Hodge test showed a sensitivity of 41% and a specificity of 83%, and the Carba NP test showed a sensitivity of 26% and a specificity of 92% for detection of carbapenemase. OXA-48 was the most frequently detected carbapenemase, followed by NDM-1. Thirty-nine percent and 27% of positive cyanide 3-chlorophenylhydrazone test organisms included active AcrA/B and OqxAB efflux pumps respectively. The result showed the Carba NP test was more specific than MHT. Data confirmed the involvement of AcrA/B and OqxAB efflux pump as a carbapenem resistance mechanism in selected bacteria. Similar to other reports from the Middle East, we found OXA-48 and NDM-1 to be the most frequent carbapenemase.

Emergence of multidrug-resistant ST11 blaKPC-2 producing Klebsiella pneumoniae coharboring blaCTX-M and blaSHV in Pakistan

“…In the current study, we detected high prevalence of carbapenem resistance with 72.8% CRKP and 65.4% CPKP strains highlighting resistance up trends compared to previous reports from Pakistan that documented up to 82.8% resistance and other reports form South Asia [14][15][16][17]. This clearly indicates that carbapenem resistance has increased in the study population over the years due to the lack of stewardship and unrestrained use of antimicrobials.…”

“…We reported higher antimicrobial resistance for carbapenems (99.2%), 3GC (> 90%) and AK (80.8%) that were derived from K. pneumoniae only. Comparatively, other studies from Pakistan reported variable antimicrobial resistance against carbapenems 1.71%, 35.1%, 38.0%, 39.1% and 11.0% [15,16,19,20] by taking into account total isolated strains. On the other hand, we observed higher susceptibility against PB (97.4%) and TGC (60.3%); however, another study reported higher TGC resistance (70.5%) [19].…”

Phenotypic and Molecular Characterization of Carbapenems Resistant Escherichia coli Isolated from Patients with Urinary Tract Infections in Ardabil Province, Iran

“…According to Dagher et al from Lebanon, results showed that among E. coli isolates, the predominant carbapenemase gene was detected as bla OXA-48 ( 30 ). Based on a study performed by Armin et al , bla OXA-48 and bla NDM-1 were the most frequently detected Carbapenemases in GNB ( 31 ). The findings of Mahmoud et al agreed with our study's findings.…”

Evaluate the Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production Among Gram-Negative Bacteria

“…Carbapenemase genes were identified by two sets of multiplex PCR for detection VIM, IMP and NDM-1, SPM-1 and two conventional PCR for KPC and OXA-48 enzyme. Primer and PCR conditions were explained previously (20).…”