Farrell David J, File Thomas M, Jenkins Stephen G
G.R. Micro Ltd., 7-9 William Rd., London NW1 3ER, United Kingdom.
J Clin Microbiol. 2007 Feb;45(2):290-3. doi: 10.1128/JCM.01653-06. Epub 2006 Nov 8.
In the United States, approximately 30% of Streptococcus pneumoniae isolates are macrolide (erythromycin [ERY]) resistant (ERSP), most commonly due to expression of the mef(A) gene previously associated with lower-level ERY resistance (ERYr; MIC=1 to 4 microg/ml). The data from the PROTEKT US surveillance study were analyzed to evaluate the prevalence and antibacterial susceptibility of mef(A)-positive ERSP. In all, 26,634 isolates of S. pneumoniae were collected in the United States between 2000 and 2004 from centers common to all years. ERYr was stable at approximately 29% over the 4 years, but the proportion of ERSP isolates positive for mef(A) alone decreased (year 1 [2000 to 2001], 69.0%; year 4 [2003 to 2004], 60.7%), with the sharpest declines seen in isolates from patients from 0 to 2 years of age. Conversely, the proportion isolates positive for both erm(B) and mef(A) increased over the duration of the present study (year 1, 9.3%; year 4, 19.1%), a change that was again most marked in patients aged <or=2 years. The majority of ERSP isolates expressing mef(A) alone exhibited higher than previously reported levels of ERYr (MIC90=16 microg/ml). However, the ketolide antibacterial telithromycin consistently demonstrated in vitro activity against these isolates over the 4 years of the study (MIC90=0.5 to 1 microg/ml).
在美国，约30%的肺炎链球菌分离株对大环内酯类药物（红霉素[ERY]）耐药（ERSP），最常见的原因是mef(A)基因的表达，该基因先前与较低水平的ERY耐药（ERYr；MIC = 1至4微克/毫升）有关。对美国PROTEKT监测研究的数据进行分析，以评估mef(A)阳性ERSP的流行情况和抗菌药敏性。2000年至2004年期间，在美国从各年份共有的中心收集了总共26,634株肺炎链球菌分离株。ERYr在这4年中稳定在约29%，但仅mef(A)阳性的ERSP分离株比例下降（第1年[2000年至2001年]，69.0%；第4年[2003年至2004年]，60.7%），在0至2岁患者的分离株中下降最为明显。相反，在本研究期间，erm(B)和mef(A)均阳性的分离株比例增加（第1年，9.3%；第4年，19.1%），这种变化在年龄≤2岁的患者中同样最为显著。大多数仅表达mef(A)的ERSP分离株表现出高于先前报道的ERYr水平（MIC90 = 16微克/毫升）。然而，在研究的4年中，酮内酯类抗菌药物泰利霉素对这些分离株始终表现出体外活性（MIC90 = 0.5至1微克/毫升）。
