HIV感染人群鼻腔携带的MRSA与MSSA菌株耐药谱及毒素基因分布特征

目的 探究广州市HIV感染人群鼻腔携带耐甲氧西林金黄色葡萄球菌(Methicillin - Resistant Staphylococcus aureus, MRSA)与甲氧西林敏感性葡萄球菌(Methicillin Sensitive Staphylococcus Aureus, MSSA)的耐药谱和毒素基因分布特征。方法 于2017年6 - 8月，便利抽取广州市某医院门诊就诊的1 001名HIV感染者并采集其鼻拭子样本，根据传统实验室方法分离鉴定出253株金黄色葡萄球菌，对鉴定出的菌株进行药物敏感性试验，利用头孢西丁纸片法和mecA扩增法鉴定MRSA，采用多重聚合酶链式反应(Polymerase Chain Reaction, PCR) 检测毒素基因。结果 253株SA菌株中，检出MRSA 119 (47.04%) 株，MSSA 134(52.96%)株。60.08%(152/253) 金黄色葡萄球菌为多重耐药SA(Multi - Drug Resistant, MDRSA)。 MRSA菌株和MSSA菌株耐药率最高的抗生素均为青霉素(89.08%，84.33%)，其次为红霉素(61.34%, 53.73%)。MRSA菌株对头孢西丁、利福平、氯霉素、四环素和米诺环素的耐药率高于MSSA菌株，差异具有统计学意义。MRSA菌株毒素基因pvl和tst检出率均为4.20%，未检出eta和etb。MSSA菌株毒素基因pvl、tst、eta和etb的检出率分别为2.99%、1.49%、2.24%和0.75%。结论 HIV感染人群鼻腔携带金黄色葡萄球菌中的MRSA和MDRSA检出率高，但MRSA和MSSA菌株pvl、 tst、eta和etb检出率低。

Distribution features of drug resistance spectrum and toxin genes for MRSA and MSSA nasal isolates from HIV-positive patients

Objective To explore the drug resistance spectrum and feature of toxin genes for MRSA and MSSA isolates from HIV-positive patients in Guangzhou. Methods The cross-sectional study was conducted from June to August 2017 in an outpatient department hospital in Guangzhou. Convenient sampling method was carried out to selected HIV-positive patients and 1 001 nasal swabs were also collected at the same time. 253 Staphylococcus aureus isolates were identified using conventional laboratory methods from HIV-positive individual’s nasal swabs. Antimicrobial susceptibility was tested using disk diffusion methods for Staphylococcus aureus. Cefoxitin disk diffusion test and mecA gene PCR assay were appliped to identified MRSA. All isolates were tested for toxin genes using PCR. Results In a total of 253 Staphylococcus aureus isolates, 119 (47.04%) isolates were MRSA and 134(52.96%) were MSSA. 60.8% (152/253) mrsa was multi-drug resistant (MDRSA). The most predominant antibiotic for MRSA and MSSA isolates were penicillin(89.08%, 84.33%), which were followed by erythromycin (61.34%, 53.73%). In a comparison of the differences in the resistance rates between MRSA and MSSA isolates, statistical significance was noted for cefoxitin, rifampin, chloramphenicol, tetracycline, and minocycline. 4.20% MRSA isolates were detected with pvl and tst genes and eta and etb genes were not found. The rates of pvl, tst, eta and etb genes for MSSA isolates were 2.99%, 1.49%, 2.24% and 0.75%, respectively. Conclusion The detection rate of MRSA and MDRSA are higher prevalence isolates from HIV-positive patients. However, the detection rates of pvl, tst ,eta and etb genes for MRSA and MSSA isolates are lower than other reports.