不同地区鸡毒支原体的分离鉴定及药物敏感性研究

Isolation, Identification and Antimicrobial Susceptibility of Mycoplasma gallisepticum from Different Areas

【目的】了解中国不同地区鸡毒支原体(Mycoplasma gallisepticum,MG)的流行和耐药情况,为禽支原体病的监测与防控提供科学依据。【方法】在广东、福建和安徽3个省份疑似MG感染的养殖场采集的43份气囊样品中分离培养和纯化MG流行菌株,并对其进行培养特性观察、生化及染色鉴定、血清学特异性鉴定、PCR测序分析、致病性试验和对常见抗菌药物敏感性试验。【结果】分离到3株疑似MG,均可使培养基颜色变黄,在固体培养基上呈典型“煎蛋”样菌落,可发酵葡萄糖,不水解精氨酸,不能利用尿素,符合MG培养特性。姬姆萨染色观察菌体形态、血清学特异性鉴定结果进一步证实分离株为MG。mgc2基因测序结果显示,3株分离株与强毒代表株亲缘关系更近。致病性试验结果显示,3株分离株与MG感染临床症状一致,发病率为70%~90%,致病力较强。药物敏感性试验结果显示,3株分离株均对恩诺沙星、替米考星、土霉素、氟苯尼考耐药,对泰万菌素和沃尼妙林均敏感,对大观霉素、金霉素、泰乐菌素和泰妙菌素的敏感性具有地域差异:福建株对大观霉素表现明显耐药,安徽株对泰妙菌素表现耐药,而广东株对大观霉素、金霉素和泰妙菌素均较敏感。【结论】本试验成功分离到3株MG,致病力较强,且均存在一定程度耐药,对药物的敏感程度有地区性差异,今后仍需加强各地区MG的药物敏感性监测,减少耐药性的产生与扩散。

【Objective】 The aim of this experiment was to investigate the prevalence and drug resistance of Mycoplasma gallisepticum(MG) in different areas of China, so as to provide a scientific basis for the surveillance, prevention and control of MG disease.【Method】 The prevalent strains were isolated and purified from the 43 infected air sacs from suspected MG infected chickens in poultry farms of Guangdong, Fujian and Anhui provinces.The isolates were identified by culture characteristics test, biochemical characteristics test, Giemsa staining, serological methods and then PCR sequencing analysis, pathogenicity and sensitivity to common antibiotics were tested.【Result】 3 isolates were obtained successfully, and could change the broth medium from red to yellow.They showed typical “fried egg”-like colony in the solid medium and could ferment glucose, not hydrolyze arginine, and not decompose urea, which were consistent with the culture characteristics of MG.Results of Giemsa staining and serological specific identification further confirmed the isolates to be MG. The sequence analysis of the mgc2 gene revealed that the 3 isolates were more closely related to the typical virulent strains.Animal challenge tests showed that the clinical symptoms of the 3 isolates were consistent with those of MG infection, and the incidence was 70%-90%, the 3 isolates had high pathogenicity.The results of antimicrobial susceptibility test showed that the 3 isolates were resistant to enrofloxacin, temicoxin, oxytetracycline and flufenicol, and were sensitive to tylvalosin and warnimilin.The sensitivity of the 3 isolates to spectinomycin, aureomycin, tyloxacin and tiamulin was different in different regions.The Fujian strain showed obvious resistance to spectinomycin, the Anhui strain showed resistance to tiamulin, and the Guangdong strain was sensitive to spectinomycin, aureomycin and tiamulin.【Conclusion】 3 MG isolates with high pathogenicity were isolated, and they were drug-resistant, their sensitivities to drugs were regional.In the future, it was still necessary to strengthen the drug sensitivity monitoring of MG in various regions to reduce the emergence and spread of drug resistance.