耐甲氧苯青霉素金黄色葡萄球菌选择培养基的研究

Study of Selective culture medium for methicillum resistance staphylococcus aureus

目的为防止耐药菌株流行,及时、准确地检出耐甲氧苯青霉素金黄色葡萄球菌(MRSA),给临床提供可靠的治疗依据。方法配制 MRSA 选择性培养基,苯唑青霉素(oxacillin)浓度分别为2.4,6μg/ml,NaCl 浓度分别为4%,6%,8%,并分别测试这些培养基对 MRSA 的敏感性和特异性及分解甘露醇的情况。结果含2μg/ml oxacillin的耐甲氧苯青霉素金黄色葡萄球菌选择培养基(MRSACM)的特异性较差。可低至76.3%;含6μg/ml 其敏感性较差,可低至69.4%;而含4μg/ml其敏感性和特异性均较好。NaCl 含量为6%其培养基的特异性又优于含量4%的培养基。结论使用含4μg/ml oxacillin,6%NaCl 的 MRSACM 的敏感性为100%,特异性≥99%,且不影响甘露醇产酸结果。此培养基配法简便,不需特殊设备,便于推广。

Objective To find out a culture medium that MRSA strains can be isolated exactly and identified in time.Methods 165 testing strains of Staphylococcus(85 MRSA Strains and 80 MASSA strains)were inoculated on MRSA selective medium composed of various concentration of oxacillin(2, 4,6μg/ml)and NaCl(4%,6%,8%),the sensitivity and specificity for MRSA were studied.Results The minimum specificity of MRSA selective medium composing of 2 μg/ml oxacillin was 76.3%.The minimum sensitivity of the medium containing 6 μg/ml oxacillin was 69.4%.The sensitivity and speci- ficity of the medium composing of 4 μg/ml oxacillin were 100% and≥99% respectively.Conclusions The culture medium contains 4 μg/ml oxacillum,and 6% NaCl for MRSA is an optimum medium,the sensitivity and specificity are 100% and ≥99% respectively.