牛源溶酪大球菌的分离鉴定及生物学特性分析

Isolation Identification and Biological Characteristic Analysis of Macrococcus Caseolyticus from Cattle

大球菌与发酵食品的香气和风味有关,鉴于该类细菌报道较少及间接对人类健康可能造成的影响,本文对牛源溶酪大球菌开展了相关研究。无菌采集新鲜牛肉组织样本,对其进行细菌分离培养,结合细菌形态学观察、生理生化试验、16S rRNA基因分析进行鉴定,采用纸片扩散法对菌株进行耐药性分析。结果显示,获得的一株革兰氏阴性菌经16S rRNA基因测序分析,其核苷酸同源性与溶酪大球菌参考株可达99%以上;生化试验鉴定,该分离株可分解α-葡萄糖苷酶、D-核糖和D-海藻糖,分解L-乳酸盐产碱和6.5%NaCl生长等;药敏试验结果显示该分离株对氯霉素、头孢曲松和庆大霉素等耐药,对四环素、新霉素等高度敏感;细菌耐药基因检测发现该菌含有头孢菌素类TEM、喹诺酮类gyrA和parC、外排泵类AcrAB等4种耐药基因。

Macrococcus is one of the pathogens causing meat spoilage.In view of the lack of reports on Macrococcus and its impact on meat safety,this study carried out a related study on Macrococcus caseolyticus from cattle.The beef tissue was collected aseptically,and the bacteria were isolated,morphological observation,physiological and biochemical test,16SrRNA gene sequencing analysis,drug sensitivity test,drug resistance gene detection,pathogenicity analysis.The isolate was gram-negative bacterium.The isolates could decompose α-glucosidase,D-ribose and D-trehalose,decompose L-lactate to produce alkali and 6.5%NaCl growth etc.The drug resistance of bacteria was investigated by in vitro antibacterial drug test.The results showed that the isolates were resistant to chloramphenicol,ceftriaxone and gentamicin,and highly sensitive to tetracycline and neomycin.The isolates contained cephalosporins TEM,quinolones gyrA and parC,and effervescent pump ACrabs.The results of animal tests showed that inoculation of the original bacteria solution did not cause the death of mice.Conclusion:The results of the study on tyrococcus lysococcus from cattle provide theoretical basis for preventing the spoilage and fermentation of meat products and their derivatives.