Bacterial microbiota of the Pantanal caiman eggs incubated in nature

ABSTRACT The Pantanal caiman productive chain has grown in Mato Grosso with the exportation of 143.383 leather pieces in 2015, whose management system (ranching) implies the artificial incubation of eggs. In this process, the bacterial contamination of the eggs influences the hatching rate. Knowledge of the naturally incubated microbiota of eggs guides the appropriate sanitary management in the incubator room. Here we present information about this microbiota and correlate it with that of other crocodilians, indicating the species with pathogenic potential. Samples were collected in 20 nests at Pantanal, and sown in blood and Mac Conckey agar. Salmonella sp. was confirmed through polymerase chain reaction technique. From the twenty-two different species of bacteria isolated, 59% are from the Enterobacteriaceae Family and 41% from other bacterial taxonomies. The similarity of findings to isolated bacteria in the crocodilians oral and/or intestinal/cloacal microbiota was of 77,27%. The most and least frequent bacteria were, respectively, Bacillus cereus, Flavobacterium multivorum and Citrobacter freundii and Escherichia hermannii, Hafnia alvei, Morganella, morganni, Salmonella sp., Serratia marcescens and Shigella sonnei. Among the isolated bacteria, 86,36% are pathogenic for crocodilians. The maternal and environmental origin of the microbiota of eggs naturally incubated is, respectively, of 77,27% and 27,27%.

摘要 马托格罗索州的潘塔纳尔凯门鳄产业链近年来持续发展，2015年其皮革出口量达143383张；该产业采用的围养（ranching）管理模式，要求对鳄卵进行人工孵化。在此流程中，鳄卵的细菌污染会直接影响孵化成功率。解析鳄卵自然孵化状态下的微生物群落组成，可为孵化室的规范化卫生管控提供科学依据。本研究针对该微生物群落展开分析，并将其与其他鳄类的微生物群落数据进行关联比对，以明确其中具备致病潜力的菌种。本研究于潘塔纳尔湿地的20处鳄巢采集样本，将其接种于血琼脂与麦康凯琼脂（Mac Conckey agar）培养基中；通过聚合酶链式反应（polymerase chain reaction，PCR）技术确认了沙门氏菌属（Salmonella sp.）的存在。本次实验共分离得到22种不同的细菌，其中59%隶属于肠杆菌科（Enterobacteriaceae Family），剩余41%属于其他细菌分类类群。本研究分离得到的菌株，与鳄类口腔、肠道/泄殖腔分离菌的群落相似度达77.27%。检出频率最高的三种细菌依次为蜡样芽孢杆菌（Bacillus cereus）、多食黄杆菌（Flavobacterium multivorum）与弗氏柠檬酸杆菌（Citrobacter freundii）；检出频率最低的细菌则包括赫尔曼埃希菌（Escherichia hermannii）、蜂房哈夫尼亚菌（Hafnia alvei）、摩根摩根菌（Morganella morganii，原文笔误为morganni）、沙门氏菌属（Salmonella sp.）、粘质沙雷氏菌（Serratia marcescens）与宋内志贺菌（Shigella sonnei）。分离得到的细菌中，有86.36%对鳄类具有致病性。自然孵化鳄卵的微生物群落，其来源占比分别为母体来源77.27%、环境来源27.27%。