Abstract: Microorganisms in the environment as well as on the surface of slaughtering equipment play a significant role in microbial cross-contamination during chicken processing in slaughterhouses. The aim of this study was to investigate the microbial community structure and antibiotic resistance genes in the water as well as on the ground and slaughtering equipment of a slaughterhouse. Moreover, Escherichia coli were isolated for drug resistance evaluation and genomic typing by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Water was sampled from the hanging, slaughtering, scalding and dehairng, evisceration, pre-cooling, packaging, refrigeration and viscus storage sections and bacterial samples were collected from the ground of each section and the surface of slaughtering equipment using sterile gauze swab. The microbial community structure was analyzed by high-throughput 16S rRNA V3–V4 gene sequencing on Illumina Hiseq, and the total bacteria and E. coli isolated were evaluated for resistance genes to 9 classes of 24 antiobiotics by PCR. The results showed that Proteobacteria, Firmicutes, and Actinobacteria were the predominant phyla in all the slaughterhouse samples and the dominant genera were spoilage and pathogenic Acinetobacter, Streptococcus, Psychrobacter and Pseudomonas. A total of 21 drug resistance genes were detected in these samples, and the prevalence of sulI, sulII, blaTEM, aadA1, floR, tetA, ereA and qnrS was more than 88.9%, which did not coincide with that in the E. coli isolates. This indicates that there may be some other strains carrying drug resistance genes and the multiple drug resistance of the E. coli isolates is serious. ERIC-PCR genotyping results showed that E. coli can be cloned and propagated along the slaughter production chain. This study will lay the theoretical foundation for exploring the relationship between microorganisms in the slaughterhouse environment and the contaminant microorganisms in chicken.

Key words: poultry slaughterhouse, microbial community structure, drug resistance gene, high-throughput sequencing