阪崎克罗诺杆菌鉴定分型方法的比较及耐药特征分析

目的 开展乳粉原料中分离的阪崎克罗诺杆菌(Cronobacter sakazakii, C. sakazakii)鉴定分型比较研究及抗生素耐药基因特征分析。方法 采用形态学观察、生理生化特征分析、基质辅助激光解吸/电离飞行时间质谱法、16S rDNA测序分析,和基于全基因组测序技术的平均核苷酸一致性分析、多位点序列分型和基于全基因组的多位点序列分型技术,建立了对分离的2株C. sakazakii的鉴定分型方法,并对不同的方法进行比较,同时预测O-血清型和抗生素抗性基因。结果 本研究中分离菌株16-26、31-3经形态学、生理生化反应、16S rDNA、质谱和平均核苷酸一致性分析,均鉴定为C. sakazakii,可信度均在95%以上; MLST预测16-26为ST新型、31-3为ST4型, O血清型均为gnd 3型、galF 2型,均含有9种抗性基因, 2株C. sakazakii分离株的抗性基因呈现出多样性。结论 通过对分离的C. sakazakii进行鉴定分型比较研究,建立了一种基于表型和分子分型的食源性致病菌鉴定分型方法,为食源性致病菌的有效防控提供了有力的技术支撑和监管依据。

Comparison of identification and typing methods of Cronobacter sakazakii and analysis of drug resistance characteristics

Objective To conduct a comparative study on the identification and typing of Cronobacter sakazakii (C. sakazakii) isolated from milk powder raw materials, and analyze the characteristics of antibiotic resistance genes. Methods Morphological observation, physiological and biochemical characteristics analysis, matrix assisted laser desorption/ionization time of flight mass spectrometry, 16S rDNA sequencing analysis, and average nucleotide consistency analysis based on whole genome sequencing technology, multi site sequence typing, and whole genome based multi site sequence typing techniques were used to establish identification and typing methods for 2 isolates of C. sakazakii. Different methods were compared, O-serotypes and antibiotic resistance genes were also predicted. Results The isolated strains 16-26 and 31-3 in this study were identified as C. sakazakii through morphology, physiological and biochemical reactions, 16S rDNA, mass spectrometry, and average nucleotide consistency analysis, with a reliability of over 95%; MLST predicts that 16-26 was ST novel, 31-3 was ST4, and O serotypes were both gnd 3 and galF 2, both containing 9 resistance genes. The resistance genes of 2 C. sakazakii isolateed exhibit diversity. Conclusion By conducting comparative studies on the identification and typing of isolated C. sakazakii, a method for identifying and typing foodborne pathogens based on phenotype and molecular typing has been established, providing strong technical support and regulatory basis for effective prevention and control of foodborne pathogens.