[Distribution of Multidrug-Resistant Bacteria and Antibiotic-Resistant Genes in Livestock Manures].

In the present study, techniques for microbial culture enumeration, 16S rDNA gene sequencing for bacterial identification, high-throughput sequencing for the multidrug-resistant bacteria (MRB) communities, and high-throughput quantitative PCR detection for the prevalence and abundance of antibiotic resistance genes (ARGs) were conducted to investigate the distribution characteristics of MRB and ARGs in chicken and swine manures. The results showed that the rates of MRB that were resistant to tetracycline, ciprofloxacin, and gentamycin simultaneously were from 7.96% to 12.40% for the different manure samples. The dominant genera of cultivable MRB were Escherichia, Acinetobacter, and Proteus, both in the chicken and swine manures. High-throughput quantitative PCR results indicated that, compared to the antibiotic free swine manure, the total enrichment of ARGs increased by 1.96×104-1.54×105 times that in the swine manure samples, with different antibiotics following the sequence of tetracyclines > β-lactams > MLSB (macrolide, lincosamide, and streptogramin B) > aminoglycosides > FCA (fluoroquinolone, quinolone, florfenicol, chloramphenicol, and amphenicol) > sulfonamides > vancomycins.