An investigation of extended-spectrum β-lactamases (ESBLs) in Klebsiella isolated from foodborne outbreaks in Iran

Abstract

Aims and backgroundsAntibiotic resistance of Enterobacteriaceae such as Klebsiella which usually caused by Extended-Spectrum β-Lactamases (ESBLs) has been an issue for public health. The aim of this study was to evaluate the presence of ESBLs in Klebsiella isolates obtained from foodborne outbreaks diarrheal samples by phenotypic and genotypic methods. Materials and methodsIn this study, 416 diarrheal samples were collected from 120 foodborne outbreaks from March 2017 to March 2018 throughout Iran. Isolation and identification of Klebsiella isolates were performed by phenotypic methods, and antibiotic susceptibility testing was accomplished by disk diffusion method. Production of ESBLs was performed using combined disc method. The presence of blaSHV, blaTEM, and the blaCTX-M genes was investigated by PCR, and the data was analyzed using SPSS version 18. ResultsOf 416 diarrheal samples, 32 isolates (7.69%) were found positive for Klebsiella, of them 24 isolates (75%) were identified as Klebsiella pneumoniae, and 8 isolates (25%) as Klebsiella oxytoca. In Klebsiella pneumoniae isolates, the highest susceptibility was seen to imipenem and piperacillin (91.7%), while the highest resistance was observed to amoxicillin and penicillin (100%). Klebsiella oxytoca isolates were also completely (100%) resistant to amoxicillin and penicillin and completely (100%) susceptible to other antibiotics. Five isolates were identified as ESBLs positive, phenotypically. Of the 32 isolates, 22 isolates (68.7%) were positive for the presence of the blaSHV, 5 isolates (15.6%) for blaCTX-M, and all 32 isolates (100%) for blaTEM genes. ConclusionAlthough Klebsiella isolates are not very common in foodborne outbreaks, but they are important due to the presence of ESBLs introducing high resistance to the common antibiotics.