Genetic profiling of extended-spectrum β-Lactamase and carbapenemase-producing Escherichia coli O157:H7 from clinical samples among diarrheal patients in Shashemene, Ethiopia.

Abstract

Background: Escherichia coli (E. coli) O157:H7, associated with diarrhea, poses a global health risk. In Ethiopia, where diarrhea is common, there is limited knowledge about these resistant strains and a lack of data on Extended-Spectrum β-Lactamase (ESBL) and carbapenemase production. Understanding the prevalence of antimicrobial resistance genes associated with ESBL and carbapenems is crucial for addressing diarrheal disease. This study aimed to investigate the genetic profile of ESBL and carbapenemase coding gene carriage in E. coli O157:H7 from clinical stool samples and evaluate antimicrobial susceptibility patterns.

Methods: A total of twenty-nine bacterial isolates obtained from diarrheal patients were subjected to conventional culture and phenotypic (Kirby Bauer disc diffusion method) testing for antimicrobial resistance. Additionally, screening for the production of ESBL (combined disk method) and carbapenemase (modified carbapenem inactivation method) was conducted. Isolates that tested positive for ESBL and carbapenemase production were further analyzed, targeting five genes (bla_NDM, bla_KPC, bla_CTX-M, bla_TEM, and bla_SHV) associated with ESBL and carbapenemase production. Data analysis was performed using SPSS version 27.0, employing logistic regression and descriptive statistics.

Results: We analyzed a total of 27 isolates that were ESBL-positive and 12 isolates that were found to produce carbapenemase phenotypically. These isolates were obtained from clinical stool samples and (9/27) 33.3% of the isolates were from under five years children, predominantly from urban areas, and those that have contact with domestic animals. Genes coding ESBL were found in (19/27) 70.4% of the isolates, the most predominant being bla_CTX-M and bla_TEM. Eight isolates carried bla_KPC, but none had bla_NDM, while five isolates carried both bla_CTX-M and bla_TEM genes. bla_SHV-carrying isolates showed phenotypic resistance to ampicillin and cephalosporins, while bla_KPC-carrying isolates exhibited resistance to ampicillin, carbapenems, and tetracycline.

Conclusion: This study identifies a significant prevalence of multidrug resistance in E. coli O157:H7, which can be attributed to the presence of resistance genes coding for ESBL and carbapenem production. Key factors contributing to this resistance, such as urban environments, children under the age of five, and domestic animal ownership, have been emphasized. Additionally, this research underscores the urgent need for enhanced surveillance and targeted interventions to address this pressing public health concern.