Nonhoff C, Denis O, Brenner A, Buidin P, Legros N, Thiroux C, Dramaix M, Struelens M J
Laboratoire de Référence MRSA-Staphylocoques, Service de Microbiologie, Hôpital Erasme, Bruxelles, Belgium.
Eur J Clin Microbiol Infect Dis. 2009 Apr;28(4):363-9. doi: 10.1007/s10096-008-0637-9. Epub 2008 Oct 15.
This study compares the performance of three chromogenic culture agar plates, chromID MRSA, MRSA-Screen and MRSA-Select, by challenging with a collection of Staphylococcus aureus strains and screening samples obtained from hospitalised patients. All chromogenic media showed excellent sensitivity (>95%) and specificity after 18 h on the methicillin-resistant Staphylococcus aureus (MRSA) collection strains, but the specificity of MRSA-Screen decreased markedly after 42 h. Sixty-eight of 1,002 screening specimens yielded MRSA on at least one medium. The sensitivity of all media to detecting MRSA after 18 h was <50%, but this increased to 75% (chromID MRSA), 81% (MRSA-Screen) and 72% (MRSA-Select) after 42 h and 85% after enrichment and plating on the same media. The specificity at 18 h was excellent, but was significantly lower for MRSA-Screen after 42 h and enrichment. In conclusion, all media showed equivalent sensitivities after 18 h of incubation and performed better when enriched before inoculation. MRSA-Screen was more sensitive but less specific than the two other media after 42 h of incubation.
本研究通过用一批金黄色葡萄球菌菌株进行挑战试验，并对从住院患者获取的筛查样本进行检测，比较了三种显色培养琼脂平板（chromID MRSA、MRSA-Screen和MRSA-Select）的性能。在耐甲氧西林金黄色葡萄球菌（MRSA）收集菌株上培养18小时后，所有显色培养基均显示出优异的敏感性（>95%）和特异性，但42小时后MRSA-Screen的特异性显著下降。1002份筛查标本中有68份在至少一种培养基上检测出MRSA。所有培养基在18小时后检测MRSA的敏感性均<50%，但在42小时后，这一比例分别增至75%（chromID MRSA）、81%（MRSA-Screen）和72%（MRSA-Select），在富集并接种于相同培养基后，敏感性达到85%。18小时时的特异性优异，但42小时及富集后，MRSA-Screen的特异性显著降低。总之，孵育18小时后，所有培养基的敏感性相当，接种前进行富集处理时表现更佳。孵育42小时后，MRSA-Screen比其他两种培养基更敏感，但特异性更低。
