Characterization of AmpC, CTX-M and MBLs types of β-lactamases in clinical isolates of Klebsiella pneumoniae and Escherichia coli producing Extended Spectrum β-lactamases in Kerman, Iran

Abstract

Background:Extended spectrum β-lactamases (ESBLs) and AmpC β-lactamases enzyme are major sources of resistance to β-lactam antibiotics especially in Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae. Increasing frequency of the co-existence of ESBLs with AmpC-β-lactamases in bacteria is a serious threat for treating bacterial infections.Objectives:The aim of this study was to determine the presence of AmpC and CTX-M types of β-lactamases in clinical isolates of E. coli and K. pneumoniae producing ESBLs.Materials and Methods:Resistance to different antibiotics was determined using the standard disk diffusion method. ESBLs, MBLs and AmpC-β-lactamases were detected by the combination double disk test (CDDT) method and polymerase chain reaction (PCR) was used to determine blaCTX-M genes in the ESBLs and AmpC positive isolates.Results:The prevalence of ESBLs and AmpC-β-lactamase producer isolates was 181 (43.8%) and 133 (37.2%), respectively. The prevalence of blaCTX-M among isolates was 61 (14.7%).Conclusions:Outbreak of isolates co-expressing AmpC-β-lactamases and ESBLs can cause serious problems in the future, regarding the treatment of infections caused by these common enteric pathogens.

Extended-Spectrum Beta-Lactamase Producing Gram Negative Bacteria in Iran: A Review

“…Surveys on the isolation of MDR non-fermenting GNB of the patients from three hospitals in Kerman indicated that all of the isolates were resistant to cefoxitin, and ESBL production was higher in A. baumannii than other tested bacterial species; but, the difference was not significant. A study from November 2007 to July 2008 on the patients admitted to hospitals in the Kerman showed that, among K. pneumoniae isolates, 44% produced ESBLs and 28% had AmpC (Mansouri et al, 2014 Khuzestan is another province in the southern part of Iran. In an 11-month study from August 2011 to July 2012, 500 Enterobacteriaceae isolates were collected from Ahvaz and the prevalence rates of CTX-M-1 genes among ESBLspositive isolates K. pneumonia were found in 26.92% (Khosravi et al, 2013).…”

Identification of Extended-Spectrum β-Lactamase Genes and AmpC-β-Lactamase in Clinical Isolates of Escherichia coli Recovered from Patients with Urinary Tract Infections in Kerman, Iran

“…Thus, imipenem is still the most active agent against ESBL and AmpC-β-lactamase-producing E. coli isolates (2,(26)(27)(28). However, in the present study, two isolates were found to be resistant to imipenem; thus, resistance to this antibiotic may increase in the future (2,29). Interestingly, in this study, the diameter of the inhibition zone around the CO disk (colistin) was zero in 4 (7.8%) isolates from inpatients.…”

“…The rate of resistance to imipenem was very low; this is similar to the results of others studies conducted in Iran and worldwide. Thus, imipenem is still the most active agent against ESBL and AmpC-β-lactamase-producing E. coli isolates (2,(26)(27)(28). However, in the present study, two isolates were found to be resistant to imipenem; thus, resistance to this antibiotic may increase in the future (2,29).…”

“…Extended-spectrum β-lactamase (ESBL) and AmpC-β-lactamase are the main enzymes involved in resistance to β-lactam antibiotics, such as extendedspectrum cephalosporins (1,2).…”

The β-Lactamase Disk Test: A Modified Method to Detect Extended-Spectrum-β-Lactamases in Multidrug-Resistant Escherichia coli Isolates

“…However all these eight isolates were considered ESBLs producing when β-lactamase disk test was used, due to hydrolysis of cefotaxime. This result may indicate the presence of multiple mechanisms of resistance to broad-spectrum cephalosporins in such isolates and when these mechanisms overlap, it leads to the reduction of CDDST sensitivity to identify the ESBLs producing isolates (3,5 ceftazidime and cefpodoxime disks alone, and plus clavulanic acid , were reported (16)(17)(18)(19). Also in other reports in 2014 and 2015 in Tehran, conducted on 100 carbapenemresistant P. aeruginosa isolates that were positive for bla TEM , bla OXA and bla SHV , only three isolates were considered as ESBLs producing by CDDST method and 97 isolates exhibited no growth inhibition zones around the cefotaxime, ceftazidime and cefpodoxime disks, alone or in combination with clavulanic acid (5, 13).…”