Molecular characterization of the β‐lactamases in Escherichia coli and Klebsiella pneumoniae from a tertiary care hospital in Riyadh, Saudi Arabia

Abstract

The widespread use of antimicrobials has increased the occurrence of multidrug resistant microbes. The commonest mechanism of antimicrobial resistance in Enterobacteriaceae is production of β-lactamases such as metallo-β-lactamases (MBL) and extended spectrum β-lactamases (ESBL). Few studies have used a molecular approach to characterize the prevalence of β-lactamases. Here, the prevalence of different β-lactamases was characterized by performing three multiplex PCRs targeting genes similar to those described in earlier publications. Antimicrobial susceptibility tests for all isolates were performed using the agar dilution method. β-lactamase was detected in 72% of the isolates, the detection rate being 64% in 2011 and 75% in 2012. The isolates were highly resistant to carbapenems such as meropenem and imipenem and susceptible to colistin and tigecycline. In this study, 22% of isolates contained both MBL and ESBL. ESBL was detected more frequently in Escherichia coli isolates, whereas carbapenemase was detected more frequently in Klebsiella pneumoniae isolates. These findings suggest the spread of multi-resistant ESBL and MBL producers in the community. Our results have implications for patient treatment and also indicate the need for increased surveillance and molecular characterization of isolates.

Prevalence of 16S rRNA methylase genes among β-lactamase-producing Enterobacteriaceae clinical isolates in Saudi Arabia

“…In agreement with previous reports (26, 32), β-lactamase positive isolates were more susceptible to colistin and tigecycline, which were the only available therapeutic options for them.…”

“…The isolates were tested only for the bla genes reported to be prevalent in this region (26) ( bla CTX-M-14 + bla TEM-1 and bla SHV ), and 83.5% of them were positive for bla TEM-1 . An Indian study (2) reported that 61.1% of MBL producers carried bla(VIM) and 2 (3%) carried bla(IMP) .…”

The molecular basis of β-lactamase production in Gram-negative bacteria from Saudi Arabia

“…In another report, Marie et al (2013) collected 4250 E. coli and K. pneumoniae isolates from a hospital in Riyadh between 2010 and 2011; they found high carbapenem resistance (30-50 %) and 72 % produced b-lactamases. ESBLs were detected more frequently in the 3358 E. coli isolates than carbapenemases (68 vs 53 %), while for the 892 K. pneumoniae isolates the frequency of detection of ESBLs and carbapenemases was similar (63 %).…”

“…The bla TEM and bla SHV genes were detected in 28 and 65 % of the isolates, respectively. Marie et al (2013) found NDM in 55 % of the 3060 E. coli and K. pneumoniae isolates from a hospital in Riyadh between 2010 and 2011. IMP and VIM were identified in, respectively, 9 and 7 % of the isolates, while KPC and OXA-48 were not detected in any of the isolates.…”

“…A noticeable increase in the prevalence of CTX-M during the study period was observed for E. coli (from 5.1 to 25.3 %) but not K. pneumoniae (from 6.4 to 7.4 %). Other class types, namely class C, non-A and non-C, were found in fewer than 10 % of the isolates (Somily et al, 2012).In another report, Marie et al (2013) collected 4250 E. coli and K. pneumoniae isolates from a hospital in Riyadh between 2010 and 2011; they found high carbapenem resistance (30-50 %) and 72 % produced b-lactamases. ESBLs were detected more frequently in the 3358 E. coli isolates than carbapenemases (68 vs 53 %), while for the 892 K. pneumoniae isolates the frequency of detection of ESBLs and carbapenemases was similar (63 %).…”