Faecal carriage of ESBL and plasmid-mediated AmpC β-lactamase genes in Klebsiella spp. and Shigella spp. isolated from inpatient and outpatient carriers in Tabriz, Iran.

Abstract

The growing incidence of community acquired infection due to Extended-Spectrum Beta-Lactamase (ESBL) - and plasmid-mediated AmpC β-lactamase prducing bacteria represent a great concern because there are few therapeutic choices. This study was aimed to determine the prevalence of faecal carriage of ESBL producing Klebsiella spp. and Shigella spp. among inpatient and outpatient and their phenotype-genotype resistance correlation that conveyed ESBL with or without AmpC genes at a university hospital in Tabriz, Iran. During March to May 2015, 200 faecal samples from hospitalized and non-hospitalized patients without gastrointestinal illness and diarrhea were cultured on MacConkey agar plate supplemented with 2 μg/mL of cefotaxime.

Bacterial identification, antimicrobial susceptibility testing and ESBLs confirmatory tests were performed according to the standard guidelines. Also, polymerase chain reaction (PCR) was used to identify the genetic determinants responsible for ESBL production (TEM, SHV, and CTX-M) and AmpC β-lactamase genes. Of 200 faecal samples analysed, 23 (11.5%) Klebsiella pneumonia, and 4 (2%) Shigella spp. were isolated. The co-resistance frequencies in isolates recovered were as follows: Ciprofloxacin, 4.3%; Gentamicin, 4.3%; Ceftazidime, 13%; Cefepime, 17.4%; amoxicillin-clavulanic acid, 47.8%; and Ampicillin, 87%. Six (26.08%) of the Klebsiella isolates had phenotypic evidence of ESBL production, while bla_SHV sequences were detected in 18 (66.6%), and bla_TEM in 11 (40.7%) isolates. Also, bla_CTX-M and bla_CMY sequences were found in 4 (17.39%) and 5 (21.7%) Klebsiella isolates, respectively. This study revealed that ESBL production was relatively prevalent in faecal carriage of Klebsiella and Shigella isolates in Tabriz. In addition, Persons attending hospital could be a reservoir of such bacteria and enzymes.

Keywords: Shigella; Klebsiella; ESBL; Faecal carriage; Iran