金黄色葡萄球菌致病毒素基因与耐药性的相关性研究

Study correlation on pathogenic genes and antibiotic resistance of staphylococcus aureus

目的研究金黄色葡萄球菌的致病毒素基因与耐药性的关系。方法对临床收集的74株金黄色葡萄球菌,采用聚合酶链反应(PCR)检测耐药基因mecA和致病毒素基因中毒休克综合征毒素-1(TSST-1)、杀白细胞毒素(PVL),采用纸片扩散法进行药敏试验,对红霉素耐药和克林霉素敏感的菌株做D-试验。结果 74株金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌(MRSA)的检出率为55.4%。MRSA除对万古霉素、呋喃妥因敏感外,对其他抗菌药物均高度耐药,甲氧西林敏感金黄色葡萄球菌(MSSA)对抗药物的耐药性较轻,两组间的耐药性差异有统计学意义(P<0.05)。PVL基因阳性的MRSA耐药性与PVL基因阴性的MRSA比较,两组间耐药性差异无统计学意义(P>0.05)。PVL基因阳性的MSSA耐药性比不携带PVL基因的MSSA强,两者间差异有统计学意义(P<0.05)。携带TSST-1基因的MRSA除对万古霉素、呋喃妥因无耐药菌株外,对其他16种抗菌药物100%耐药。D-试验阳性菌株占所检菌株的10.8%,占红霉素耐药、克林霉素敏感菌株的88.9%。只有1株PVL基因阳性的MRSA D-试验阳性。结论 MRSA的耐药性非常严重,表现为对多种抗菌药物同时耐药,并且具有较高的红霉素诱导克林霉素耐药率;PVL和TSST-1可增强金黄色葡萄球菌的致病力及MSSA的耐药性,增加了临床抗感染治疗的难度。

Objective To investigate correlation on pathogenic genes and antibiotic resistance of staphylococcus aureus.Methods 74 strains of staphylococcus aureus were isolated from the various clinical specimens.PVL gene,mecA gene and Tsst-1 gene were conducted using a novel multuplex PCR.The antimicrobial resistnace was measured by agar diffusion method.The inducible clindamycin resistance was checked by D-test.Results The incidence of MRSA from 74 strains of staphylococcal aureus was 55.4%,most of which were multidrug-resistant strains,but susceptible to vancomycin and furadantin.Antimicrobial resistnace of MSSA was lower than MRSA.The difference of MRSA and MSSA had significance（P〈0.05）.Between antibiotic resistnace of MRSA with PVL gen and MRSA with no PVL gene,the two methods did not show significant difference（P〉0.05）.Antimicrobial resistnace of MSSA with PVL gene was more serious than MSSA without PVL gene.The two methods have significant difference（P〈0.05）.MRSA with TSST-1 gene was resistant to 16 antibiotics,except for vancomycin,furadantin.D-test positive strains accounted for 10.8% among detected strains and 88.9% among erythromycin-resistant,clindamycin-susciptible strains.Only 1 strain of D-test positive MRSA had TSST-1 gene.Conclusion MRSA strains are seriously resistant to antibiotics.They are characterized by multidrug resistance and high rate of inducible clindamycin resistance.PVL gene and Tsst-1 gene can increase pathogenic power and antibiotic-resistance of MSSA.This brings difficulty to clinic treatment.