Green M, Wadowsky R M, Barbadora K
Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pennsylvania.
J Clin Microbiol. 1990 Mar;28(3):484-8. doi: 10.1128/jcm.28.3.484-488.1990.
A cross-sectional survey of vancomycin-resistant gram-positive cocci (VRGPC) in the feces of children was initiated after several bacteremic infections with these organisms occurred at our hospital. A selective medium consisting of colistin-nalidixic acid agar, 5% sheep blood, vancomycin (5 mg/liter), and amphotericin B (8 mg/liter) was developed to isolate VRGPC. A single stool specimen submitted to the clinical microbiology laboratory from each of 48 patients was inoculated onto the medium. Plates were incubated at 35 degrees C with 5% carbon dioxide and examined at 24, 48, and 72 h. Susceptibilities were determined by broth microdilution. A total of 14 isolates from 11 of 48 (22%) children were recovered. The density of growth ranged from a single colony to 2+. The VRGPC were identified as Leuconostoc lactis (n = 2), Lactobacillus confusus (n = 4), Enterococcus species (n = 5), and Lactococcus lactis (n = 3). One strain of Lactobacillus confusus was recovered from both the stool and the blood of one of these patients. The MICs of vancomycin were 4 micrograms/ml for one of the isolates, 8 micrograms/ml for four of the isolates, and more than 16 micrograms/ml for the remaining eight isolates. All isolates were susceptible to both penicillin and ampicillin. Only 1 of the 11 children had received prior treatment with vancomycin. We conclude that low concentrations of VRGPC may be common in the gastrointestinal tracts of children.
在我院发生数起由这些微生物引起的菌血症感染后，我们开展了一项针对儿童粪便中耐万古霉素革兰氏阳性球菌（VRGPC）的横断面调查。我们研发了一种选择性培养基，其成分包括黏菌素 - 萘啶酸琼脂、5%羊血、万古霉素（5毫克/升）和两性霉素B（8毫克/升），用于分离VRGPC。从48名患者中每人提交一份粪便标本接种到该培养基上。平板在35℃、5%二氧化碳条件下培养，并在24、48和72小时进行检查。药敏试验通过肉汤微量稀释法测定。48名儿童中有11名（22%）共分离出14株菌株。生长密度从单个菌落到2+不等。VRGPC鉴定为乳酸明串珠菌（n = 2）、困惑乳杆菌（n = 4）、肠球菌属（n = 5）和乳酸乳球菌（n = 3）。其中一名患者的粪便和血液中均分离出一株困惑乳杆菌。其中一株分离株的万古霉素最低抑菌浓度（MIC）为4微克/毫升，4株为8微克/毫升，其余8株大于16微克/毫升。所有分离株对青霉素和氨苄西林均敏感。48名儿童中只有1名曾接受过万古霉素治疗。我们得出结论，低浓度的VRGPC在儿童胃肠道中可能很常见。
