不同的培养条件对检出耐甲氧西林葡萄球菌的影响

The effect of culture conditions on the resistance level of methicillin resistant Staphylococci

用苯唑西林对１９９４～１９９６年临床分离的３２０株金葡球菌和４４株凝固酶阴性萄萄球菌进行分析检测，检出５８株耐甲氧西林金葡球菌（１８．１％）及２１株耐甲氧西林凝固酶阴性萄萄球菌（４２．３％）。耐药菌株对苯唑西林的耐药水平受某些生长条件的显著影响，在３０℃、ｐＨ７．２、培养基中加入４％ＮａＣｌ及孵育时间为４８ｈ比在３７℃、ｐＨ５．２、培养基中不加ＮａＣｌ及孵育时间为２４ｈ的耐药水平为高，其中尤以ｐＨ影响为大。但对苯唑西林敏感的金萄球菌包括ＡＴＣＣ２５９２３则几乎不受上述条件的影响。

Fifty eight strains of MRSA and 21 methicillin resistant coagulase negative Staphylococci (CNS) were detected from 320 and 44 clinical isolates S.aureus and CNS. Oxacillin was used to detect MRSA and methicillin resistant CNS in this study. MRSA and MRSE accounted for 18.1% and 42.3% in Staphylococci population isolated in 1994￣1996 in Chongqing district. The levels of resistance in MRSA to oxacillin were affected markedly by growth conditions, of 30℃, pH7.2, cultures containing 4% NaCl and incubated for 48 were higher than those of 37℃, pH5.2, salt free media and incubated for 24 hours. Among those, the pH was the decisive one. But the level of resistance of MSSA strains were very little affected by the different growth conditions.