Occurrence of tet(A) and tet(M) Resistant Genes in Clinical and Environmental Escherichia coli Isolates: A Case Study

Vollständiger Abstract

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Background: Resistant genes of tetracycline are widely distributed in the environment, this indicates the presence of a source for these genes, hence the possibility of their application in clinical treatments. Objective: The purpose of the present study was to determine the occurrence of specific tetracycline-resistant genes tet (A) and tet (M) in E. coli. Methodology: The study was conducted in the Department of Medical Laboratory Technologies, Al-Rafidain University, Baghdad, Iraq. A total number of 60 samples were tested for Escherichia coli. Environmental and clinical samples were collected from January 2026 to March 2026 Al-Yarmuk Hospital and Al-Karkh Hospital in Baghdad, Iraq. All samples underwent analysis, isolation, and diagnosis based on phenotype and genotype tests (tet(A) and tet(M) detected by Polymerase Chain Reaction. Results: A total of 40 of Escherichia coli strains were identified. (28.3%) were isolated from the urine samples, whereas the remaining (38.3%) were isolated from environmental samples. The DNA amplification for the Escherichia coli 16S genes was positive for all samples. The analysis of the tetracycline-resistant genes (tetA and tetM) showed the presence of tetA in only the environmental samples, while tetM was absent in both sample types. Conclusion: The high prevalence of the most prevalent tetracycline resistance gene (tetA) even in non-clinical isolates may reflect the presence of a potential reservoir of this type of resistance, thus limiting the resurgence of tetracycline even when used in combination therapies. Bangladesh Journal of Infectious Diseases, June 2026;13(1): 215-220