title: Clonal diversity of CTX-M-producing, multidrug-resistant Escherichia coli from rodents.
abstract: This territory-wide study investigated the occurrence of faecal carriage of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli among wild rodents from the 18 districts in Hong Kong. Individual rectal swabs were obtained from the trapped animals and cultured in plain and selective media. A total of 965 wild rodents [148 chestnut spiny rats (Niviventer fulvescens), 326 Indo-Chinese forest rats (Rattus andamanensis), 452 brown rats (Rattus norvegicus) and 39 black rats (Rattus rattus)] were sampled. ESBL carriage was 0 % in chestnut spiny rats, 0.6 % in Indo-Chinese forest rats, 7.7 % in black rats and 13.9 % in brown rats. Among brown rats, the prevalence of ESBL carriage differed markedly by geographical location: absent in two districts, low (7-10 %) in six districts, moderate (11-19 %) in seven districts and high (21-50 %) in three districts. Nonetheless, there was no correlation between the prevalence of ESBL in brown rats and human population density in the 18 districts. CTX-M-type enzymes were detected in 92.0 % of the ESBL-producing isolates, of which 83.1 % were resistant to three or more non-β-lactam drugs. The CTX-M producing isolates were genetically diverse but a large proportion (47.8 %) were included in six successful clones that are strongly associated with human diseases and CTX-M dissemination, viz. sequence type complex [STC]10/phylogroup A, STC23/phylogroup B1, STC38/phylogroup D, STC155/phylogroup B1, ST405/phylogroup D and ST131/phylogroup B2. In conclusion, our results show that brown rats often carry potentially zoonotic clones of CTX-M producing, multidrug-resistant E. coli. The potential for rats to be a source of CTX-M producing E. coli for humans deserves further consideration.
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China plho@hkucc.hku.hk.
authors: Pak-Leung
authors: PL
authors: Ho
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors: Wai-U
authors: WU
authors: Lo
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors: Eileen L
authors: EL
authors: Lai
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors: Pierra Y
authors: PY
authors: Law
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors: Sammy M
authors: SM
authors: Leung
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors: Ya
authors: Y
authors: Wang
authors: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors: Kin-Hung
authors: KH
authors: Chow
mesh_terms: D000818:Animals; D002353:Carrier State / Q000382:microbiology / Q000662:veterinary; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006723:Hong Kong; D008297:Male; D058889:Molecular Typing; D051381:Rats; D012377:Rodentia / Q000382:microbiology*; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D001618:beta-Lactamases