糖尿病足患者耐甲氧西林金黄色葡萄球菌感染相关因素及基因型

Influencing factors and pathogenic genotypes of methicillin-resistant Staphylococcus aureus in patients with diabetic foot

目的探讨感染耐甲氧西林金黄色葡萄球菌(MRSA)糖尿病足(DF)患者的临床特点及致病菌基因型分析。方法回顾性分析2014年2月-2017年1月医院收治的380例DF患者的临床资料,对患者足部溃疡基底分泌物进行细菌分离,对分离病原菌进行培养、鉴定及药敏试验,同时根据感染的葡萄球菌为甲氧西林耐药菌或敏感菌,将感染金黄色葡萄球菌(SA)患者分为MRSA组25例和甲氧西林敏感金黄色葡萄球菌(MSSA)组78例,记录DF患者病原菌分布的临床特点及SA的耐药特点,同时比较MRSA和MSSA患者的一般资料,分析MRSA感染的相关因素,并分析MRSA菌株致病基因白细胞毒素基因(PVL)表达情况。结果 380例DF患者溃疡部位分离出病原菌349株,其中革兰阳性菌202株占57.88%,其中SA 103株,MRSA 25株,MSSA 78株;革兰阴性菌138株占39.54%,真菌9株占2.58%。MRSA菌株与MSSA菌株在青霉素G、苯唑西林、氧氟沙星、左氧氟沙星、阿奇霉素、头孢呋辛、头孢噻肟、利福平、呋喃妥因等耐药率比较,差异有统计学意义(P<0.05)。入院前6个月抗菌药使用、溃疡病程、溃疡面积、合并高血压和低蛋白血症是DF患者感染MRSA的相关因素(P<0.05)。PCR结果显示,25株MRSA均表达mecA耐药基因,且其中4株MRSA携带致病基因PVL。结论 SA是DF溃疡患者常见感染病原菌,且DF患者中MRSA存在多药耐药现象且均表达mecA耐药基因,少数MRSA携带致病基因PVL,临床上应当合理、调整抗菌药物使用,减少耐药性菌株的产生。

OBJECTIVE To explore the clinical characteristics and pathogenic genotypes of methicillin-resistant Staphylococcus aureus （MRSA） in patients with diabetic foot （DF）. METHODS The clinical data of 380 cases of DF patients from Feb. 2014 to Jan. 2017 were retrospectively analyzed. The foot ulcer hasal secretion was given bacterial isolation, and the isolated pathogenic bacteria were given the culture, identification and drug susceptibili- ty test. The infected S.aureus （SA） patients were divided into MRSA group （n=25） and MSSA （methicillin-sen- sitive S. aureus） group （n= 78） according to the infection of S.aureus as methicillin-resistant bacteria or suscepti- ble bacteria. The clinical characteristics of pathogen distribution in DF patients and the drug resistance of SA were recorded, and the general data of MRSA patients and MSSA patients were compared. The risk factors of MRSA infection and the expression of MRSA strain pathogenic gene leukocyte toxin gene （PVL） were analyzed.RESULTS There were 349 strains of isolated pathogenic bacteria in the 380 DF patients, including 202 gram-positive strains （57.88%） （103 strains of S.aureus, 25 strains of MRSA and 78 strains of MSSA）, 138 strains of gram-negative bacteria （39.54%） and 9 fungi strains （2.58M）. The differences of resistant rates between MRSA strains and MSSA strains to penicillin G, oxacillin, ofloxacin, levofloxacin, azithromycin, cefuroxime, cefotaxime, rifampi- cin and nitrofurantoin were significant （P^0.05）. The use of antimicrobial agents at 6 months before admissionulcer disease course, ulcer area, combined hypertension and hypoproteinemia were the related risk factors for MR- SA infection of DF patients. PCR results showed that 25 strains of MRSA expressed mecA resistance genes, and four of them carried pathogenic gene PVL. CONCLUSION SA is a kind of common infection pathogens in DF ulcer patients, and there are multiple drug resistance with the expression of mecA resistance gene in DF patients and with a small number of MRSA carrying pathogenic gene PVL, therefore clinical application should be reasonable to adjust the use of antimicrobial agents and reduce the occurrence of drug resistance strains.