溶血葡萄球菌耐药性及耐药基因的检测

Antibiotics Resistance of Staphylococcus haemolyticus and Detection of Resistance Genes

目的了解临床分离溶血葡萄球菌的耐药并探讨其耐药基因的存在状况。方法对56株临床分离的溶血葡萄球菌采用纸片扩散法(K-B法)检测14种抗菌药物的敏感性,聚合酶链反应(PCR)法检测mecA、ermA/B/C及tetM 3种耐药基因,并与相关药敏表型比较。结果56株溶血葡萄球菌对万古霉素无耐药;对苯唑西林的耐药率为89.3%,对红霉素的耐药率达85.7%,对青霉素、头孢唑林、头孢噻肟、阿莫西林/克拉维酸、环丙沙星、庆大霉素、复方新诺明、亚胺培南的耐药率均>50%;对利福平和四环素的耐药率较低,分别为3.5%和14.3%;mecA基因检测阳性率为78.6%,有6株苯唑西林表型耐药而mecA基因阴性,其耐药性可能与β-内酰胺酶的大量产生有关;ermA/B/C基因检测阳性率为51.8%,tetM基因检测阳性率为14.3%。结论溶血葡萄球菌对大多数抗菌药物均有较高的耐药率,其多重耐药及高耐药机制十分复杂,还有待进一步深入研究。

OBJECTIVE To study the antimicrobial resistance of the Staphylococcus haemolyticus and investigate the genes related to resistance. METHODS Susceptibility of 14 antimicrobial agents against 56 strains of S. haemolyticus collected from clinical specimens were determined by the disk diffusion method; mecA, ermA/B/ C and tetM genes of these strains were determined by polymerase chain reaction（PCR）, and compared with the results of susceptibility test. RESULTS No vancomycin resistance was found in total 56 strains. The resistant rate to oxacillin and erythromycin was 89.3% and 85.7%. The resistant rates to penicillin G,cephazoline,cefotaxime, amoxicillin/CA,ciprofloxacin,gentamicin, compound sulfamethoxazole and imipenem were higher than 50%. The resistant rates to rifampin and tetracycline were much lower, which were 3.5% and 14.3%. The positive rate of mecA gene was 78. 6% ,while 6 strains showed resistance in susceptibility test but had a negative result in mecA gene detection. The resistance of them might relate to generation of beta-lactamase. The positive rate of ermA/B/C gene was 51.8%, The positive rate of tetM gene was 14.3%. CONCLUSIONS The S. haemolyticus is resistant to majority of the antibiotics with high resistant rates. The exact mechanism of resistance is expected to be studied more in the future.