牛粪沼渣中多重耐药细菌的环境风险

为研究牛粪厌氧发酵沼渣中多重耐药细菌的环境污染风险，选用畜禽养殖中常用的5种抗生素(红霉素、氨苄青霉素、金霉素、链霉素、环丙沙星)对牛粪沼渣中可培养抗生素抗性细菌进行筛选。结果表明：多重耐药细菌的比例高达76.5%,其中，抗5种和4种抗生素的细菌分别有11,21株。所有多重耐药细菌均对氨苄青霉素具有抗性，抗红霉素、金霉素和链霉素的细菌分别占总多重耐药细菌数的92.0%,89.3%,61.3%。通过细菌16S rRNA测序鉴定，32株具有4种以上抗性的细菌分别属于福氏志贺氏菌、摩根氏菌和假中间苍白杆菌，均为重要的临床致病菌。使用全基因组测序对7株典型多重耐药细菌携带的抗性基因进行分析，共检测出28种抗生素抗性基因，对应9种抗生素抗性类型。通过分析抗性基因及插入序列所在位点信息发现，多重耐药细菌普遍携带含有抗性基因和插入序列共存的质粒，表明抗性基因具有高度的可移动性和较强的传播风险。综上所述，牛粪沼渣中含有大量的多重耐药细菌，可视作抗生素抗性基因的储存库，应重视沼渣农业资源化利用过程中的环境风险监测与评估。

Study on Environmental Risks of Multidrug-Resistant Bacteria in Biogas Residue of Cattle Manure

In order to investigate the pollution risk of multidrug-resistant bacteria in biogas residue from anaerobic digestion of cattle manure, five antibiotics (erythromycin, ampicillin, chlortetracyline, streptomycin and ciprofloxacin) that commonly used in livestock and poultry breeding were used to screen the culturable antibiotic-resistant bacteria from biogas residue of cattle manure. The results showed that the proportion of multidrug-resistant bacteria was as high as 76.5%, with 11 and 21 strains of bacteria resistant to five and four antibiotics, respectively. All multidrug-resistant bacteria were resistant to ampicillin, and bacteria resistant to erythromycin, chlortetracyline and streptomycin accounted for 92.0%, 89.3% and 61.3% of the total multidrug-resistant bacteria count, respectively. Through bacterial 16S rRNA sequencing, 32 strains with more than four kinds of resistance were identified as Shigella flexneri, Morganella morganii and Ochrobactrum pseudointermedia, respectively, all of which were important clinical pathogens. Resistance genes carried by seven typical multi-drug resistant bacteria strains were analyzed using whole genome sequencing, and a total of 28 antibiotic resistance genes were detected, corresponding to nine antibiotic resistance types. Analysis of the antibiotic resistance genes and insertion sequences locus information revealed that multidrug-resistant bacteria generally carried plasmids containing both resistance genes and insertion sequences, indicating that these resistance genes had high mobility and strong transmission risk. In conclusion, the biogas residue of cow manure contains a large number of multidrug-resistant bacteria, which can be regarded as a reservoir of antibiotic resistance genes, and attention should be paid to the environmental risk monitoring and assessment during the agricultural resource utilisation of biogas residue.