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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Antimicrobial resistance patterns and integron carriage of Escherichia coli isolates causing community-acquired
Aysegul Copur-Cicek1, Osman Birol Ozgumus1, Aysegul Saral2
1Department of Medical Microbiology, Faculty of Medicine, Recep Tayyip Erdoğan University, Rize, Turkey.
Abstract:
We aimed to observe antimicrobial resistance patterns and integron carriage of Escherichia coli isolates causing community-acquired infections. Two hundred sixty-eight E. coli strains were obtained from outpatients with various infections at different polyclinics at the 82nd Year of State Hospital in Rize, Turkey. Susceptibility to antimicrobials was tested using a disk diffusion method. The presence of integrons was examined using PCR with specific primers. Positive PCR results were confirmed by sequencing. A broth mating method was used for conjugation assays. Extragenic palindromic-PCR was performed using the oligonucleotide primer BOXA1R. Resistance frequency for ampicillin, trimethoprim/sulfamethoxazole, and tetracycline was determined as 50.6%, 33.5%, and 36.8% respectively. No strains were resistant to amikacin. Seventy isolates were positive for the intI1 gene, of which 49 carried gene cassettes. Eleven isolates were positive for the intI2 gene, eight of which carried gene cassettes. Seven gene cassettes (dfrA1, dfrA5, dfrA7, dfrA17, aadA1, aadA5, and sat2) were predominantly harbored in integrons. We detected conjugative plasmids harboring integrons in two E. coli strains. Four strain clusters were yielded by BOX-PCR fingerprints showing that they were clonally related. No apparent relationship occurred among class 1 and 2 integron-carrying strains. We conclude that integrons are widespread in genetically variable E. coli strains and will continue to mediate dissemination of resistance genes in the community.
Insights
Integrons are common in community-acquired Escherichia coli infections, carrying resistance genes like dfrA and aadA. These mobile genetic elements will likely continue spreading antimicrobial resistance in the community.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- Community-acquired infections pose a significant public health challenge.
- Antimicrobial resistance (AMR) is a growing threat, necessitating surveillance of resistance patterns.
- Integrons are mobile genetic elements known to contribute to AMR dissemination.
Purpose of the Study:
- To investigate antimicrobial resistance patterns in Escherichia coli isolates from community-acquired infections.
- To determine the prevalence and characteristics of integron carriage in these E. coli strains.
- To explore the potential for integron-mediated gene transfer and clonal spread.
Main Methods:
- Disk diffusion method for antimicrobial susceptibility testing.
- Polymerase Chain Reaction (PCR) for integron gene detection (intI1, intI2) and sequencing.
- Broth mating method for conjugation assays.
- Extragenic palindromic-PCR (BOX-PCR) for clonal relatedness analysis.
Main Results:
- High resistance rates observed for ampicillin (50.6%), trimethoprim/sulfamethoxazole (33.5%), and tetracycline (36.8%).
- No resistance to amikacin was detected.
- Integrons (intI1 and intI2) were prevalent, with many carrying gene cassettes (e.g., dfrA, aadA, sat2).
- Conjugative plasmids carrying integrons were identified in two strains.
- BOX-PCR revealed clonal relationships in four E. coli clusters.
Conclusions:
- Integrons are widespread in genetically diverse E. coli causing community infections.
- These mobile genetic elements play a crucial role in the dissemination of antimicrobial resistance genes.
- Continued monitoring of integron carriage and resistance patterns is essential for public health.
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