Tickler Isabella A, Goering Richard V, Mediavilla Jose R, Kreiswirth Barry N, Tenover Fred C
Cepheid, 904 Caribbean Drive, Sunnyvale, CA 94089.
Department of Medical Microbiology and Immunology, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178.
Diagn Microbiol Infect Dis. 2017 Aug;88(4):342-347. doi: 10.1016/j.diagmicrobio.2017.04.016. Epub 2017 May 6.
We characterized spa types, SCCmec types, and antimicrobial resistance patterns of 516 methicillin-resistant Staphylococcus aureus (MRSA) isolates, collected between 2011 and 2014 from nares and blood cultures of United States patients. Among nares isolates, 45 spa types were observed; 29.9% were t002/SCCmec II and 30.9% were t008/SCCmec IV. Among blood isolates, 40 spa types were identified; 24.4% were t002/SCCmec II and 39.9% were type t008/SCCmec IV. Compared to data from our 2009-2010 survey, the percentage of t008/SCCmec IV isolates from nares increased significantly (20.4%-30.9%; P=0.004) while the percentage from positive blood cultures remained similar (39.2% versus 39.9%; P=0.921). There were also significant changes in the overall antimicrobial resistance patterns observed, including the decrease of the clindamycin, erythromycin, levofloxacin and moxifloxacin multidrug resistance pattern, likely the result of t002/SCCmec II strains being displaced by t008/SCCmec IV strains. Rates of high-level mupirocin resistance did not change significantly from our past study (4.1% compared to 4.7%; P=0.758) but an increase in low-level resistance, particularly among t002/SCCmec II isolates, was observed.
我们对2011年至2014年间从美国患者的鼻腔和血培养物中收集的516株耐甲氧西林金黄色葡萄球菌（MRSA）分离株的spa型、SCCmec型和抗菌药物耐药模式进行了特征分析。在鼻腔分离株中，观察到45种spa型；29.9%为t002/SCCmec II型，30.9%为t008/SCCmec IV型。在血培养分离株中，鉴定出40种spa型；24.4%为t002/SCCmec II型，39.9%为t008/SCCmec IV型。与我们2009 - 2010年调查的数据相比，鼻腔中t008/SCCmec IV分离株的百分比显著增加（20.4% - 30.9%；P = 0.004），而血培养阳性分离株的百分比保持相似（39.2%对39.9%；P = 0.921）。观察到的总体抗菌药物耐药模式也有显著变化，包括克林霉素、红霉素、左氧氟沙星和莫西沙星多重耐药模式的减少，这可能是t002/SCCmec II菌株被t008/SCCmec IV菌株取代的结果。与我们过去的研究相比，高浓度莫匹罗星耐药率没有显著变化（4.1%对4.7%；P = 0.758），但观察到低浓度耐药率有所增加，特别是在t002/SCCmec II分离株中。
