北京市售鸽肉中大肠杆菌和沙门氏菌分离鉴定及耐药性分析

目的对北京市售鸽肉中大肠杆菌和沙门氏菌进行分离鉴定,并对分离菌株进行抗生素耐药性分析。方法使用缓冲蛋白胨水增菌液淋洗肉鸽样品后,使用大肠杆菌(E.coli,EC)增菌肉汤和丹麦国家血清研究院(Statens Serum Institute, SSI)肠道细菌琼脂分离大肠杆菌,使用四硫磺酸盐(tetrasulfonate, TT)增菌肉汤和木糖赖氨酸脱氧胆盐(xyloselysinedeoxycholate,XLD)琼脂平板分离沙门氏菌,使用生化鉴定进行可疑菌确认。参照CLSI2016版推荐的肉汤稀释法,测定15种抗生素对所分离大肠杆菌和沙门氏菌的最低抑菌浓度(minimalinhibitory concentrations,MICs)。结果样品(n=200)中大肠杆菌(n=104)检出率为52.0%,沙门氏菌(n=41)检出率为21.0%。所分离的42株沙门氏菌菌株均对头孢他啶、氨曲南、厄他培南和替加环素敏感,对氨苄西林、萘啶酸、环丙沙星、四环素、复方新诺明和氯霉素的耐药率在30%以上,部分菌株对头孢噻肟(4.8%)和黏菌素(2.4%)耐药。所分离的104株大肠杆菌菌株均对替加环素敏感,对氨苄西林、头孢噻肟、氨曲南、萘啶酸、环丙沙星、四环素、复方新诺明、氯霉素和卡那霉素的耐药率在30%以上,部分菌株对头孢他啶(2.9%)、厄他培南和(1.0%)和黏菌素(9.6%)耐药。结论北京市售鸽肉是耐药大肠杆菌和沙门菌的重要储存库,相较于我国其他地区市售猪肉,鸡肉,牛肉等分离的耐药菌株,表现出不同的耐药谱,耐药率相对较低,但是北京市售鸽肉所携带的菌株已经累积了复杂的耐药特征,有必要对其中存在的耐药机制进行系统研究。

Isolation, identification and drug resistance analysis of Escherichia coli and Salmonella in Beijing pigeon meat

Objective To isolate and identify the Escherichia coli and Salmonella in the pigeon meat sold in Beijing, and analyze the antibiotic resistance of isolates. Methods After washing the samples of the pigeons with the buffer protein hydrolysate, the E. coli (EC) enrichment broth and the Danish National Institute of Serum Institute (SSI) enteric bacteria agar were used to isolate E. coli. Salmonella was isolated from tetrasulfonate (TT) enrichment broth and xylose lysine deoxycholate (XLD) agar plates, and biochemical identification was used for confirmation of suspicious bacteria. The minimum inhibitory concentrations (MICs) of 15 antibiotics against E. coli and Salmonella isolated were determined according to the broth dilution method recommended by CLSI 2016. Results The detection rate of E. coli (n=104) in the sample (n=200) was 52.0%, and the detection rate of Salmonella (n=41) was 21.0%. The 42 strains of Salmonella isolated were sensitive to ceftazidime, aztreonam, ertapenem and tigecycline, resistance to ampicillin, nalidixic acid, ciprofloxacin, tetracycline, co-trimoxazole and chloramphenicol over 30%, and some strains were resistant to cefotaxime (4.8%) and colistin (2.4%). The 104 strains of E. coli isolated were all sensitive to tigecycline, resistance to ampicillin, cefotaxime, aztreonam, nalidixic acid, ciprofloxacin, tetracycline, cotrimoxazole, chloramphenicol and kanamycin over 30%, and some strains were resistant to ceftazidime (2.9%), ertapenem and (1.0%) and colistin (9.6%). Conclusion Beijing pigeon meat is an important repository for drug-resistant E. coli and Salmonella. Compared with other commercially available pork, chicken, beef and other resistant strains in other regions of China, they show different drug resistance profiles and lower resistance rates. However, the strains carried by pigeons sold in Beijing have accumulated complex drug resistance characteristics, and it is necessary to systematically study the resistance mechanisms existing therein.