Bert F, Leflon-Guibout V, Le Grand J, Bourdon N, Nicolas-Chanoine M-H
Service de microbiologie, hôpital Beaujon, AP-HP, 100, boulevard du Général-Leclerc, 92110 Clichy, France.
Pathol Biol (Paris). 2009 Feb;57(1):56-60. doi: 10.1016/j.patbio.2008.07.017. Epub 2008 Oct 8.
Outbreaks of vancomycin-resistant enterococci have been increasingly reported in France over the last three years. We report here, the emergence of a vancomycin-dependent enterococci isolate following glycopeptide therapy.
An Enterococcus faecium isolate that required vancomycin for growth was cultured from the stools of a liver transplant recipient who was colonised with vancomycin-resistant enterococci and who received vancomycin treatment for methicillin-resistant Staphylococcus aureus infection. The resistant isolate and the dependent isolate were typed by pulsed-field gel electrophoresis. The sequence of the ddl gene coding for the D-Ala: D-Ala ligase was analysed.
The dependent isolate was primary cultured onto a vancomycin-containing screening medium and could not be subcultured in the absence of vancomycin. Both the resistant and dependent isolates harboured the vanA gene and they had the same DNA restriction pattern after pulsed-field gel electrophoresis. Dependence on vancomycin was associated with a 1-bp deletion in the D-Ala: D-Ala ligase gene leading to an early stop odon.
Cultures onto vancomycin-containing media are warranted for clinical specimens from patients, who are known to carry vancomycin-resistant enterococci and receive vancomycin therapy.
在过去三年里，法国越来越多地报告了耐万古霉素肠球菌的暴发情况。在此，我们报告了在糖肽类治疗后出现的一株依赖万古霉素的肠球菌分离株。
从一名肝移植受者的粪便中培养出一株需要万古霉素才能生长的粪肠球菌分离株，该受者感染了耐甲氧西林金黄色葡萄球菌，携带耐万古霉素肠球菌，并接受了万古霉素治疗。通过脉冲场凝胶电泳对耐药分离株和依赖分离株进行分型。分析了编码D - 丙氨酸：D - 丙氨酸连接酶的ddl基因序列。
依赖分离株最初接种在含万古霉素的筛选培养基上，在没有万古霉素的情况下无法传代培养。耐药分离株和依赖分离株均携带vanA基因，经脉冲场凝胶电泳后它们具有相同的DNA限制性图谱。对万古霉素的依赖性与D - 丙氨酸：D - 丙氨酸连接酶基因中的1个碱基对缺失有关，导致提前出现终止密码子。
对于已知携带耐万古霉素肠球菌并接受万古霉素治疗的患者的临床标本，有必要接种在含万古霉素的培养基上进行培养。
