南美白对虾肠道内乳酸菌的分离鉴定及其对抗生素的耐药性

以南美白对虾为研究对象,采用平板分离法从其肠道内筛得26株乳酸菌,通过16S rRNA测序鉴定可归为4种:乳酸乳球菌乳亚种L. lactis subsp. lactis、台湾乳球菌L. taiwanensis、格式乳球菌L. garvieae、乳酸乳球菌L. lactis。选取7株具有代表性的乳酸菌,用PCR的方法检测对虾中检出率较高的6类18种抗性基因(ARGs)在乳酸菌中的分布,辅以平板涂布的方法用抗生素选择性培养基研究乳酸菌对抗生素的耐药性。研究发现:7株乳酸菌具有相似的耐药谱,对四环素、磺胺吡啶、乙酰螺旋霉素表现出耐药性(抑菌率<50.00%),对盐酸金霉、土霉素、硫酸庆大霉素、氯霉素、红霉素敏感(抑菌率100%);含有多重抗性基因,ARGs的检出率:磺胺类(92.86%)>四环素类(53.06%)>喹诺酮类(23.81%)>氨基糖苷类(4.76%)>氯霉素类=大环内酯类(0.00%),其ARGs基因型与菌株的抗生素表型并不能完全吻合。

Antibiotic Resistance of Lactic Acid Bacteria Strains Isolated from Intestinal Microflora of Penaeus vannamei

In this work, P. vannamei was used as the research object. The 26 strains of lactic acid bacteria were isolated from the intestine and classified into 4 species: L. lactis subsp. Lactis, L. taiwanensis, L. garvieae and L. lactis. Seven representative lactic acid bacteria were selected to study their resistance to antibiotics from the genotype and phenotype based on the methord of PCR as well as the antibiotic selective plate coating method. The results showed that 7 strains of lactic acid bacteria had similar drug resistance spectrum, indicating resistance to tetracycline, sulfapyridine, acetylspiramycin (inhibition rate < 50.00%) while being sensitive to gold mold, oxytetracycline, chlortetracycline sulfate, chloramphenicol and erythromycin (inhibition rate 100%). More than 3 ARGs were detected in all strains with the detection rate of ARGs were as the follows: sulfonamides (92.86%) > tetracyclines (53.66%) > quinolones (23.81%) > aminoglycosides (4.76%) > chloramphenicol = macrolides (0.00%). The ARGs genotype did not exactly match the antibiotic phenotype of the strain.