Ojo K K, Ulep C, Van Kirk N, Luis H, Bernardo M, Leitao J, Roberts M C
Department of Pathobiology, Box 357238, School of Public Health and Community Medicine, University of Washington, Seattle, WA 98195, USA.
Antimicrob Agents Chemother. 2004 Sep;48(9):3451-6. doi: 10.1128/AAC.48.9.3451-3456.2004.
Of the 176 randomly selected, commensal, gram-negative bacteria isolated from healthy children with low exposure to antibiotics, 138 (78%) carried one or more of the seven macrolide resistance genes tested in this study. These isolates included 79 (91%) isolates from the oral cavity and 59 (66%) isolates from urine samples. The mef(A) gene, coding for an efflux protein, was found in 73 isolates (41%) and was the most frequently carried gene. The mef(A) gene could be transferred from the donors into a gram-positive E. faecalis recipient and a gram-negative Escherichia coli recipient. The erm(B) gene transferred and was maintained in the E. coli transconjugants but was found in 0 to 100% of the E. faecalis transconjugants tested, while the other five genes could be transferred only into the E. coli recipient. The individual macrolide resistance genes were identified in 3 to 12 new genera. Eight (10%) of the oral isolates and 30 (34%) of the urine isolates for which the MICs were 2 to >500 microg of erythromycin per ml did not hybridize with any of the seven genes and may carry novel macrolide resistance genes.
在从低抗生素暴露的健康儿童中随机挑选出的176株共生革兰氏阴性菌中，138株（78%）携带了本研究中检测的七种大环内酯类抗性基因中的一种或多种。这些分离株包括79株（91%）来自口腔的分离株和59株（66%）来自尿液样本的分离株。编码外排蛋白的mef(A)基因在73株分离株（41%）中被发现，是携带最频繁的基因。mef(A)基因可从供体转移到革兰氏阳性粪肠球菌受体和革兰氏阴性大肠杆菌受体中。erm(B)基因可转移并在大肠杆菌接合子中维持，但在所检测的粪肠球菌接合子中，其存在比例为0至100%，而其他五个基因只能转移到大肠杆菌受体中。在3至12个新属中鉴定出了单个大环内酯类抗性基因。每毫升红霉素最低抑菌浓度为2至>500微克的8株（10%）口腔分离株和30株（34%）尿液分离株未与七种基因中的任何一种杂交，可能携带新的大环内酯类抗性基因。
