AUTHOR=Huang Zixian , Li Yuanyuan , Cai Chang , Dong Ning 

TITLE=Isolation, Molecular Characterization, and Antimicrobial Resistance of Selected Culturable Bacteria From Crayfish (Procambarus clarkii)

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.911777

DOI=10.3389/fmicb.2022.911777

ISSN=1664-302X

ABSTRACT=<p>Red swamp crayfish (<italic>Procambarus clarkii</italic>) have become one of the favorite aquatic products in China. The modern farming mode which uses antibiotics to prevent diseases could impact the bacteria in crayfish intestines. Here, we determined the distribution and antimicrobial resistance phenotypes of the selected culturable bacteria in crayfish intestines and characterized an isolate with last-line antibiotic resistance determinant. Totally, 257 strains were isolated from 115 crayfish. These strains were highly diverse, with <italic>Citrobacter</italic> sp. (<italic>n</italic> = 94, 36.6%) and <italic>Aeromonas</italic> sp. (<italic>n</italic> = 88, 34.2%) being dominant. Other isolates belonged to genera <italic>Pseudomonas</italic>, <italic>Myroides</italic>, <italic>Morganella</italic>, <italic>Klebsiella</italic>, <italic>Acinetobacter</italic>, <italic>Proteus</italic>, <italic>Enterobacter</italic>, <italic>Kluyvera,</italic> and <italic>Escherichia</italic>. Most strains from crayfish were susceptible to all tested antibiotics. None of the isolates carried last-line antibiotic resistance genes except one <italic>Escherichia coli</italic> isolate with <italic>bla</italic><sub>NDM-5</sub> was detected, which is the first report of <italic>bla</italic><sub>NDM-5</sub>-positive <italic>E. coli</italic> isolate from red swamp crayfish. Whole-genome sequencing suggested it belonged to ST48 and carried several resistance genes. <italic>bla</italic><sub>NDM-5</sub> was located within an Tn<italic>3000</italic>-like transposon linked to an external 5 bp sequence (ACTAT) on both sides on a IncHI1B/HI1A/FIA multi-replicon plasmid. This transposon was considered to be acquired by replicative transposition mediated by IS<italic>3000</italic>. The emergence of bacteria with last-line antibiotic resistance genes in crayfish poses serious threat to public health since crayfish could act as a reservoir for the transfer of resistance to humans.</p>