北京市九城区超市及农贸市场零售整鸡中弯曲菌含量与耐药性分析

摘要

目的 调查北京市9个城区超市及农贸市场零售环节整鸡样品中弯曲菌含量及抗生素耐药性情况.方法 于2012年8月至2013年7月,选取北京市9个城区的27个超市和18个农贸市场进行调查,共采集零售整鸡样品240份.用改良Karmali、Preston培养基对样品中弯曲菌数量进行测定,采用革兰染色、乳胶凝集和多重PCR方法分别对样品中的弯曲机进行纯化、分离和类型鉴定,并采用美国农业部弯曲菌定量计数方法,计算样品中弯曲菌含量.采用琼脂稀释法,测定弯曲菌对8种抗生素的最低抑菌浓度(MIC).结果 弯曲菌检出率为26.3％(63/240),共计检出弯曲菌151株,其中空肠弯曲菌85株,结肠弯曲菌66株.弯曲菌含量的P25、P50、P75分别为7.5、45.0、350.0 CFU/g.空肠弯曲菌、结肠弯曲菌对抗生素耐药率为:阿奇霉素[AZI,13％(11/85)、82％(54/85)],氯霉素[CHL,33％(28/85)、42％(28/85)],环丙沙星[CIP,95％(81/85)、100％(85/85)],多西环素[DOX,38％ (32/85)、80％(53/85)],红霉素[ERY,12％ (10/85)、82％(54/85)],庆大霉素[GEN,25％(21/85)、68％(45/85)],四环素[TET,67％(57/85)、73％ (62/85)],所有菌株均对美罗培南(MEP)敏感.空肠弯曲菌多重耐药率为55％ (47/85),结肠弯曲菌为86％(57/66)(x2=16.70,P＜0.01).在151株弯曲菌中,共发现21个抗生素耐药谱,其中空肠弯曲菌耐药谱为20个,结肠弯曲菌耐药谱为10个.空肠弯曲菌中,耐药谱CIP-DOX-TET型比例最高,为22％(19/85),CIP-TET、CHL-CIP-TET和CHL-CIP-GEN型分别为14％(12/85)、9％(8/85)和7％(6/85).结肠弯曲菌中,耐药谱AZI-CHL-CIP-DOX-ERY-GEN-TET型比例最高,为35％ (23/66),AZI-CIP-DOX-ERY-GEN-TET和AZI-CIP-DOX-ERY-TET型分别为21％(14/66)和15％(10/66).结论 北京市9个城区零售整鸡样品弯曲菌检出率和含量较高,尤其以农贸市场现宰杀整鸡样品中弯曲菌含量较多,零售整鸡样品中检出的弯曲菌耐药形势严峻.%Objective To determine Campylobacter contamination level and antimicrobial resistance patterns from chicken carcasses in supermarkets and farmer's markets of 9 districts in Beijing.Methods From August 2012 to July 2013,whole chicken carcasses (n =240) were collected from 27 supermarkets and 18 farmer's markets of nine districts in Beijing.The level of Campylobacter contamination was enumerated by plate counting method using the modified Karmali and modified Preston agar.Presumptive Campylobacter isolates were identified and characterized by gram stain,agglumination test and a multiplex PCR method.The level of Campylobacter contamination was calculated following the USDA/FSIS Campylobacter enumeration method.Selected 151 Campylobacter isolates were further characterized by minimal inhibitory concentrations (MICs) of eight antimicrobials.Results A total of 26.3％ (63/240) of the retail whole chicken carcasses were contaminated by Campylobacter and 151 Campylobacter isolates were recovered,including 85 Campylobacter jejuni isolates and 66 Campylobacter coli isolates.The P25,P5o,P75 of Campylobacter contamination concentration were 7.5,45.0 and 350.0 CFU/g,respectively.The antimicrobial resistance rate of C.jejuni and C.coli were as the following:azithromycin (AZI,13％ (11/85),82％ (54/85)),chloramphenicol (CHL,33％ (28/85),42％ (28/85)),ciprofloxacin (CIP,95％ (81/85),100％ (85/85)),doxycycline(DOX,38％ (32/85),80％ (53/85)),erythromycin (ERY,12％ (10/85),82％ (54/85)),gentamicin (GEN,25％ (21/85),68％ (45/85)),tetracycline (TET,67％ (57/85),73％ (62/85)),all isolates were susceptible to meropenem (MEP).The multi-drug resistance ratio of C.jejuni (55 ％ (47/85)) was significantly lower than that (86％ (57/66)) of C.coli (x2 =16.70,P ＜ 0.01).Among 151 Campylobacter isolates,21 antimicrobial resistance patterns were identified,including 20 patterns among C.jejuni isolates and 10 patterns among C.coli isolates.Among C.jejuni isolates,CIP-DOX-TET was dominant (22％ (19/85)),followed by CIP-TET (14％ (12/85)),CHL-CIP-TET (9％ (8/85)) and CHL-CIP-GEN (7％ (6/85)).Among C.coli isolates,AZI-CHL-CIP-DOX-ERY-GEN-TET (35％ (23/66)) was the dominant,followed by AZI-CIP-DOX-ERY-GEN-TET (21％ (14/66)) and AZI-CIP-DOX-ERY-TET (15％ (10/66)).Conclusion Our findings showed a high prevalence and concentration of Campylobacter contamination in retail chicken carcasses of nine districts in Beijing,especially the on-site slaughtered chicken from the farmer's markets.The resistance levels of these recovered Campylobacter isolates were serious.