Detection of Escherichia coli Producing CTX-M-1-Group Extended-Spectrum β-Lactamases from Pigs in Aichi Prefecture, Japan, between 2015 and 2016

Japanese journal of infectious diseases

Jun-ichi Wachino¹  Yoshichika Arakawa¹  Noriyuki Nagano²  Takaaki Kondo³  Kumiko Kawamura³  Chihiro Norizuki³  Masahiro Suzuki⁴ 

[1] Department of Bacteriology, Nagoya University Graduate School of Medicine;Department of Health and Medical Sciences, Shinshu University Graduate School of Medicine;Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine;Laboratory of Bacteriology, Aichi Prefectural Institute of Public Health

关键词: extended-spectrum β-lactamase;    pig;    prevalence;    molecular characterization;    multilocus sequence typing;   

DOI  :  10.7883/yoken.JJID.2017.206

学科分类：传染病学

来源: National Institute of Infectious Diseases

【 摘 要 】

We investigated the prevalence and characteristics of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates from Japanese pigs. A total of 345 pig fecal specimens were collected from 30 farms in the Aichi prefecture of Japan between June 2015 and April 2016, and 22 unique ESBL-producing E. coli were isolated from 16 samples spanning 8 farms. The ESBL types included CTX-M-15 (54.5%), CTX-M-55 (27.2%), CTX-M-3 (0.9%), and CTX-M-14 (0.9%). The predominant plasmid replicon type was IncN, and the isolates carried blaCTX-M-55. Nine sequence type (ST)s, including ST117, ST1706, ST38, and ST10, were detected in the ESBL-producers, but no B2-O25-ST131 was found. ESBL producers were highly resistant to cefotaxime, ceftiofur, and tetracycline, but were susceptible to imipenem, amikacin, and fosfomycin (FOM), although 2 ST354 isolates showed resistance to ciprofloxacin. All 11 chloramphenicol-resistant isolates, including ST117 (n = 6) and ST38 (n = 3) isolates, harbored floR, and the 2 FOM-resistant ST38 isolates harbored fosA3. Our results suggest that pigs do not act as direct reservoirs in the transmission of ESBL genes to E. coli in humans. However, ST117 E. coli carrying IncN-type plasmids mediating blaCTX-M-55 were isolated from several different farms, suggesting the potential for future spread in Japan. Therefore, plasmid sequence analyses and continuous surveillance are necessary from an epidemiological point of view and are required to better protect against ESBL-producer transmission.

【 授权许可】

Unknown