耐甲氧西林金黄色葡萄球菌环境影响因素研究

Effects of environmental impact factors on methicillin-resistant Staphylococcus aureus

目的揭示耐甲氧西林金黄色葡萄球菌(MRSA)产生的环境影响因素,为预防和控制MRSA的产生提供理论依据。方法用临床常用消毒剂对甲氧西林敏感金黄色葡萄球菌(MSSA)进行诱导,对比诱导前后的药敏结果并检测其耐药基因。结果 8株MSSA和实验室标准菌株ATCC 25923共9株菌中,经消毒剂诱导后有5株变为耐药,其中4株在临床常用消毒剂的持续加量作用下,其抑菌环内出现了有细菌生长或抑菌环直径变为零的现象,且均获得了mecA基因变成了MRSA,个别的还获得了smr基因,有的丢失了norA基因。结论 MSSA潜在耐药趋势,经小剂量临床常用消毒剂诱导可以发生基因突变而获得新的耐药基因变身为MRSA,提示消毒剂不合理使用是MRSA形成的重要原因之一,医疗机构急需强化消毒剂合理使用管理,以便遏止MRSA的产生,防止MRSA暴发流行。

OBJECTIVE To reveal the environmental impact factors for the emergence of methicillin-resistant Staphylococcus aureus （MRSA） ,so as to provide the theory basis for the prevention and control of MRSA emergence .METHODS The clinical disinfectants were used to induce methicillin-sensitive S .aureus （MSSA） into MRSA ,the susceptibility before and after inducing was compared to detect the resistant gene .RESULTS After sustained induction by disinfectants ,five strains in the total nine strains including eight cefoxitin-sensitive S .au-reus and one standard bacterial strain ATCC 25923 became drug- resistant and four strains of them had the situation of zero bacterial growing or zero diameter of inhibition ring after continuous adding of the common used clinical disinfectants .All strains obtained mecA gene and changed into MRSA ,some obtained smr gene and some lost norA gene according to the resistance gene detection .CONCLUSION By inducing with disinfectants used in clinical practice ,MSSA can got resistance genes by gene mutation and become MRSA .The results suggest that the abuse of disinfectants is one of the important factors of the generating of MRSA .Medical institutions must improve the management of the use of disinfectants ,so as to suppress the formation of MRSA and prevent the outbreak of M RSA .