Extended-Spectrum β-Lactamase and Carbapenemase producing Escherichia coli O157:H7 among diarrheic patients in Shashemene, west Arsi, Ethiopia
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Date
2023-06
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Addis Ababa University
Abstract
Background: Escherichia coli (E. coli) O157:H7 has been found in various sources across the globe, and until
recently, it was uncommon for this pathogen to produce Extended Spectrum β-Lactamase (ESBL) and
Carbapenemase. However, recent reports from different regions have shown that ESBL-producing E. coli O157:H7
is becoming more prevalent. In Ethiopia, while there is sufficient knowledge about the epidemiology of E. coli
O157:H7 in the country's different food supply chains, there is a lack of information regarding the extent of disease
caused by this pathogen and its production of ESBL and Carbapenemase.
Objectives: To isolate E. coli O157:H7, determine its antimicrobial susceptibility profiles, characterize its ESBL and
Carbapenemase production from stool specimens collected among diarrheic patients and explore the association of E.
coli O157:H7 infection with demographic and clinical features of diarrheal patients in Shashemene, west Arsi,
Ethiopia.
Methods: A total of 423 study participants were included from July 1, 2022, to November 25, 2022, in this prospective
healthcare facility-based cross-sectional study among all patients with diarrhea. The bacterial pathogen was isolated
and identified by colony characteristics, Gram stain, and standard biochemical tests using API 20E as well as
utilization of sorbitol and serotyping by antisera for O157 antigen. Each identified isolate was screened and tested for
ESBL and Carbapenemase production phenotypical and further characterized at the molecular level for 2
Carbapenemase (blaNDM, blaKPC) and 3 ESBL coding gens (blaCTX-M, blaTEM, and blaSHV). The data were
entered into SPSS version 26.0 software for analysis. Bi-variant and multi-variant analyses Were employed using a
logistic regression model for further analysis and were interpreted based on the odds ratio and level of statisticasignificance at a p-value <0.05.
Result: Upon laboratory investigation, E. coli O157:H7 strain was found in 38/423 (9%) study participants from this
majority of the participants [262 (61.9%)] were males with a 1.6:1 male: female ratio and 81(19.1%) of the participants
were less than five years old and 14 (3.3%) of patients were elders aged above 55 years. Living in urban area, having
domestic animal and having ≥5 family size were significantly associated with E. coli O157:H7 cases. High
antimicrobial resistance was observed on Ampicillin [38, (100%)] followed by Amoxicillin with clavulanic acid [34,
(89.5%)]. However, all isolates were sensitive to ciprofloxacin. Twenty-seven (71.1%) and 12 (31.6%) isolates were
phenotypically confirmed to be ESBL and carbapenemase producers, respectively. The genotypic testing revealed that
the most abundantly found ESBL genes were blaTEM group 15 (79%) followed by blaCTX-M group 12 (63%) and
blaSHV group 2(10%). Additionally, from the 12 carbapenemase-positive isolates, 8 (66.6%) were confirmed to have
the blaKPC group gene and none of the isolates were positive for blaNDM group.
Conclusion: The E. coli O157:H7 isolates from this study exhibited a high level of resistance to some of the
antimicrobials tested. The magnitude of ESBL and Carbapenemase production among these isolates was found to be
high. High resistance of Ampicillin and Amoxicillin/Clavulanic acid was observed among ESBL, and carbapenemase-
producing isolates and Ciprofloxacin was found to be the most effective drug against both ESBL producers and non-
producers. blaTEM group gene was the most abundant ESBL coding gene found and blaKPC group gene was the only
gene found in our isolates that code for Carbapenamese.
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Keywords
Antimicrobial susceptibility, ESBL, Carbapenemase, Diarrhea, E. coli O157:H7, Shashemene