金黄色葡萄球菌生物被膜基因型的分子鉴定

本文选用常见的典型食源性微生物金黄色葡萄球菌,从食品微生物安全角度出发,采用生物被膜菌落结晶紫染色法定量检测58株金黄色葡萄球菌菌株生物被膜的形成能力。并对金黄色葡萄球菌生物被膜相关基因型进行分型研究,包括ica调控子分型(ica A、ica D、ica BC)与粘附特性分型(agr、atl E和aap)研究。结果显示,所有检测菌株均能生成生物被膜,其中3株能生成强粘附性生物被膜,占5.2%;生成中等生物被膜能力菌株有23株,占39.7%;32株金黄色葡萄球菌生成弱粘附生物被膜,占55.2%。实验所用的58株菌株中有48株能扩增出ica A基因,56株扩增出ica D基因,57株扩增出ica BC基因,56株扩增出agr,分别有53株和57株染色体中存在aap和atl E基因。本实验的结论:ica操纵子为金黄色葡萄球菌生物被膜形成所必须,aap基因可能作为促进金黄色葡萄球菌生物被膜形成的一个独立因素。而atl E,agr基因是金黄色葡萄球菌生物被膜粘附过程中形成所必须的调节因子。

Molecular Identification of the Genotype of Staphylococcus aureus Biofilm

Typical foodborne Staphylococcus aureus (SA) was selected to investigate microbiological safety. The biofilm-forming ability of 58 SA strains was quantitatively determined using crystal violet staining of biofilm. The biofilm-associated SA genes including those associated with regulation (icaA, icaD, and icaBC) and adhesion property (agr, atlE, and aap) were studied. The result demonstrated that all strains tested formed biofilms, which were strongly adhesive in three (5.2%), moderately adhesive in 23 (39.7%) and weakly adhesive in 32 (55.2%) strains. The icaA gene was amplified from 48 isolates and icaD and icaBC were amplified from 56 and 57 strains, respectively. The agr, aap, and atlE genes were amplified from the genomes of 56, 53, and 57 isolates, respectively. The results indicated that the ica operon is required for SA biofilm formation, the aap gene may act as an independent factor for promoting SA biofilm formation, while the atlE and agr genes are necessary regulatory factors for biofilm adhesion.