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Prevalence and Genetic Characterization of Antimicrobial-resistant Escherichia coli from Wild Boar Meat in Japan
Shiori Yamamoto1,2, Tatsuya Nakayama3, Masashi Uema4
1Department of Nutrition and Dietetics, Kamakura Women's University, 6-1-3 Ofuna, Kamakura-shi, Kanagawa, 247-8512, Japan. syamamoto@kamakura-u.ac.jp.
Abstract:
Antimicrobial-resistant bacteria must be controlled from a "One Health" perspective, including in wild animals and associated products. We examined the prevalence and genetic characteristics of antimicrobial-resistant Escherichia coli in wild boar meat from a local market in Japan. A total of 152 E. coli isolates were recovered from 51 of 62 wild boar meat samples (82.3%). Among these isolates, 11 (7.2%) were resistant to one or more antimicrobial agents, including ampicillin, streptomycin, gentamicin, kanamycin, and tetracycline. Representative genes for antimicrobial resistance, such as the blaTEM, strA, strB, aacC2, aphA1, tetA, and tetB genes, from E. coli isolates exhibiting antimicrobial resistance were detected using PCR. Plasmid sequencing revealed that three representative multidrug-resistant isolates (WB18-2, WB39-2 and WB48-1) carried conjugable plasmids (such as IncF, IncX1, IncY, and IncR) that harbored antimicrobial resistance genes and Tn3 family transposons. The aph(6)-Id, aph(3")-Ib, and tetB genes were found on Tn5393-like transposons; the tetA gene, on Tn1721-like transposons; and the blaTEM gene, on Tn5393-like or Tn3.1 transposons. In contrast, the aacC2, aadA1, aadA2, sul2, sul3, and dfrA12 genes were independent of Tn3 family transposons. These data indicated that the prevalence of antimicrobial-resistant E. coli in wild boar meat was low; however, antimicrobial resistance factors have the potential to be transferred among bacteria via conjugative plasmids.
Insights
Antimicrobial-resistant Escherichia coli (E. coli) were found in wild boar meat in Japan. While prevalence was low, resistance genes on plasmids show potential for transfer, highlighting One Health concerns.
Area of Science:
- Veterinary Microbiology
- Food Safety
- Genetics of Antimicrobial Resistance
Background:
- Antimicrobial resistance (AMR) is a global health threat requiring a One Health approach.
- Wild animals can act as reservoirs and disseminators of antimicrobial-resistant bacteria.
Purpose of the Study:
- To investigate the prevalence and genetic characteristics of antimicrobial-resistant Escherichia coli (E. coli) in wild boar meat from a Japanese market.
- To identify antimicrobial resistance genes and mobile genetic elements associated with resistance in these isolates.
Main Methods:
- Isolation and identification of E. coli from wild boar meat samples.
- Antimicrobial susceptibility testing of E. coli isolates.
- Polymerase chain reaction (PCR) for detecting antimicrobial resistance genes.
- Plasmid sequencing to analyze mobile genetic elements and gene location.
Main Results:
- E. coli was detected in 82.3% of wild boar meat samples.
- 7.2% of E. coli isolates exhibited resistance to one or more antimicrobial agents.
- Multidrug-resistant isolates carried conjugable plasmids harboring resistance genes and transposons.
- Specific resistance genes were located on various transposons, while others were independent.
Conclusions:
- The prevalence of antimicrobial-resistant E. coli in wild boar meat is relatively low.
- Conjugative plasmids carrying antimicrobial resistance genes pose a potential risk for horizontal gene transfer.
- Findings underscore the importance of monitoring AMR in wildlife for One Health strategies.
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