Boken D J, Chartrand S A, Goering R V, Kruger R, Harrison C J
Department of Pediatrics, Creighton University, Omaha, NE 68178, USA.
Pediatr Infect Dis J. 1995 Oct;14(10):879-84. doi: 10.1097/00006454-199510000-00012.
We obtained nasopharyngeal cultures for Streptococcus pneumoniae from 54 children ages 2 to 24 months attending an Omaha child-care center (CCC) in April 1994. Thirty-two (59%) of the 54 children were colonized with S. pneumoniae belonging to serotypes 23, 19, 6 and 11. Seventeen (53%) of the pneumococcal isolates were highly resistant to penicillin (minimal inhibitory concentration > or = 2.0 micrograms/ml; HR-SP) and 7 (22%) were intermediately resistant to penicillin (0.12 < or = minimal inhibitory concentration < or = 1.0 microgram/ml; IR-SP). Within each pneumococcal capsular serotype, there were 1 to 3 DNA subtypes based on pulsed field gel electrophoresis analysis. A single pulsed field gel electrophoresis strain predominated in most CCC rooms, suggesting horizontal transmission among cohorted children. Nasopharyngeal cultures obtained 4 months later revealed similar S. pneumoniae colonization rates (28 of 52, 54%); however, only 2 (7%) of 28 isolates were HR-SP and 11 (39%) were IR-SP. Colonization with resistant pneumococci persisted after 4 months in 4 (12%) of 34 children cultured on both occasions. Antibiotic use by attendees had decreased notably between the two sampling periods, suggesting that selective pressure within the CCC might contribute to seasonal variation in colonization rates with HR-SP and IR-SP. We conclude that multiple genetic clones of penicillin-resistant pneumococci can occur simultaneously in a single CCC, especially during periods of heavy antibiotic selection pressure. However, individual clones of penicillin-resistant S. pneumoniae may be spread from child to child, suggesting that colonization with penicillin-resistant S. pneumoniae should now be considered a CCC-associated phenomenon.
1994年4月，我们从奥马哈一家儿童保育中心（CCC）的54名2至24个月大的儿童中获取了肺炎链球菌的鼻咽培养物。54名儿童中有32名（59%）定植了23、19、6和11型肺炎链球菌。17株（53%）肺炎球菌分离株对青霉素高度耐药（最低抑菌浓度≥2.0微克/毫升；HR-SP），7株（22%）对青霉素中度耐药（0.12≤最低抑菌浓度≤1.0微克/毫升；IR-SP）。基于脉冲场凝胶电泳分析，每个肺炎球菌荚膜血清型内有1至3个DNA亚型。在大多数CCC房间中，单一的脉冲场凝胶电泳菌株占主导地位，这表明在同组儿童中存在水平传播。4个月后获得的鼻咽培养物显示肺炎链球菌定植率相似（52名中的28名，54%）；然而，28株分离株中只有2株（7%）是HR-SP，11株（39%）是IR-SP。在两次培养的34名儿童中，有4名（12%）在4个月后仍持续定植耐药肺炎球菌。两次采样期间，参与者的抗生素使用显著减少，这表明CCC内的选择压力可能导致HR-SP和IR-SP定植率的季节性变化。我们得出结论，耐青霉素肺炎球菌的多个基因克隆可在单个CCC中同时出现，尤其是在抗生素选择压力较大的时期。然而，耐青霉素肺炎链球菌的单个克隆可能在儿童之间传播，这表明耐青霉素肺炎链球菌的定植现在应被视为与CCC相关的现象。
