异质性万古霉素中介金黄色葡萄球菌的流行病学及其感染的临床特征

Epidemiological and clinical infection features of heterogeneous vancomycinintermediate Staphylococcus aureus

目的了解重庆医科大学附属第一医院临床分离异质性万古霉素中介金黄色葡萄球菌(hVISA)流行状况及其感染的临床特征。方法采用琼脂稀释法对该院2012-2015年临床分离的金黄色葡萄球菌进行万古霉素MIC检测,按CLSI2016年版标准判断结果;菌群曲线下面积(PAP-AUC)法进行hVISA、万古霉素中介金黄色葡萄球菌(VISA)筛检;回顾性分析临床标本分离出金黄色葡萄球菌患者的临床资料。结果 105例患者纳入研究,共分离得金黄色葡萄球菌105株,分离的菌株中耐甲氧西林金黄色葡萄球菌(MRSA)61株,占58.1%;PAP-AUC法筛检出hVISA19株,占18.1%,筛检出VISA10株,占9.5%;105例金黄色葡萄球菌感染患者中,医院感染52例,其中MRSA感染36例,占69.2%;社区获得感染53例,其中MRSA感染25例,占47.2%。医院感染中MRSA占比大于社区感染(P<0.05);社区感染53例中检出hVISA 11株,检出率为20.8%,医院感染52例中检出hVISA 8株,检出率为15.4%,社区感染与医院感染中hVISA检出率差异无统计学意义(P>0.05);hVISA与非hVISA感染患者临床转归差异无统计学意义(P>0.05),VISA与非VISA感染患者临床转归差异也无统计学意义(P>0.05)。hVISA与非hVISA感染患者住院时间差异无统计学意义,VISA与非VISA感染患者住院时间差异也无统计学意义(P>0.05)。结论该院hVISA检出率较高,社区感染与医院感染中hVISA检出率差异无统计学意义,MRSA与MSSA中hVISA检出率差异也无统计学差异。hVISA感染患者住院时间并未发现较非hVISA感染患者有所延长,临床转归也未发现与非hVISA感染患者有所差别,应增加更多标本量以更准确地了解本地区hVISA的流行状况及临床特征。

Objective To investigate the prevalence and clinical characteristics of heterogeneous vancomycin-intermediate Staphylococcus aureus （hVISA） in the First Affiliated Hospital of Chongqing Medical University. Methods Clinical isolates of S. aureus were collected from the hospital during the period from 2012 to 2015 and were tested for susceptibility to vancomycin usingagar dilution method. The results were interpreted according to CLSI 2016 breakpoints. VISA and hVISA strains were screened out by population analysis profile-area under the curve （PAP-AUC）. E-test was carried out to determine the MIC of VISA. The clinical data of the patients infected with S. aureus were reviewed retrospectively. Results A total of 105 patients were included in this analysis. And 105 strains of S. aureus were isolated from these patients, including methicillin-resistant S. aureus （MRSA） strains （58.1%, 61/105）. PAP-AUC identified 19 （18.1%） hVISA strains and 10 （9.5%） VISA strains. Overall, 52 of the 105 patientswere nosocomial infections and 53 community infections. The prevalence of MRSA was 69.2% （36/52） in nosocomial infections,higher than that in community infections （47.2%, 25/53）（P〈0.05）. The prevalence of hVISA in community infections （20.8%, 11/53） did not show significant difference from that in nosocomial infections （15.4%, 8/52） （P〉0.05）. The clinical outcome （P〉0.05） and length of hospital stay （P〉0.05） did not show significant difference between hVISA and non-hVISA infections, or between VISA and non-VISA infections. Conclusions The prevalence of hVISA is high in this hospital, which does not show difference between S. aureus nosocomial infection and community infection, or between MRSA and MSSA. The length of hospital stay of hVISA infection is not significantly longer than that of nonhVISA infection. The clinical outcome of hVISA infection does not show difference from that of non-hVISA infection. Larger sample size is required to better understand the prevalence and clinical features of hVISA.