Gatermann S G, Koschinski T, Friedrich S
Abteilung für Medizinische Mikrobiologie, Ruhr-Universität Bochum, Bochum, Germany.
Clin Microbiol Infect. 2007 Aug;13(8):777-81. doi: 10.1111/j.1469-0691.2007.01749.x. Epub 2007 May 14.
In total, 494 isolates of coagulase-negative staphylococci (CoNS) were identified to the species level by biochemical tests and sodA sequencing. Erythromycin resistance phenotypes were determined and specific resistance genes were identified by PCR. The prevalence of erythromycin resistance varied widely among staphylococcal species, from 0% in Staphylococcus lugdunensis to almost 90% in Staphylococcus haemolyticus. Most (63%) erythromycin-resistant isolates carried constitutively expressed erm(C) as the sole resistance determinant, with the notable exception of Staphylococcus hominis subsp. hominis, which carried inducible erm(C). The erm(A) and erm(B) determinants were comparatively rare. The msr(A) gene was carried by 20-30% of all erythromycin-resistant isolates, with little variation among species, and was combined in 16.7% of isolates with mph(C), a resistance gene of unknown clinical relevance found previously in isolates of veterinary origin. No erythromycin resistance that could not be attributed to the genes investigated was detected. It was concluded that the presence of methylases cannot be assumed in CoNS isolates that appear erythromycin-resistant and clindamycin-susceptible; thus, methods that detect the export mechanism should be used with clinically significant isolates to indicate whether use of clindamycin may be effective. In Staphylococcus epidermidis and S. haemolyticus, 46% and 66%, respectively, of erythromycin-resistant, clindamycin-susceptible isolates were susceptible to clindamycin therapy.
通过生化试验和sodA测序，共鉴定出494株凝固酶阴性葡萄球菌（CoNS）至种水平。通过PCR测定红霉素耐药表型并鉴定特定耐药基因。红霉素耐药率在葡萄球菌种间差异很大，从路邓葡萄球菌的0%到溶血葡萄球菌的近90%。大多数（63%）红霉素耐药菌株携带组成型表达的erm(C)作为唯一的耐药决定因素，但人葡萄球菌人亚种是显著的例外，其携带可诱导的erm(C)。erm(A)和erm(B)决定因素相对少见。msr(A)基因存在于所有红霉素耐药菌株的20% - 30%中，种间差异不大，并且在16.7%的菌株中与mph(C)组合，mph(C)是先前在兽医来源的菌株中发现的临床相关性未知的耐药基因。未检测到不能归因于所研究基因的红霉素耐药情况。得出的结论是，对于表现出红霉素耐药但克林霉素敏感的CoNS分离株，不能假定存在甲基化酶；因此，对于具有临床意义的分离株，应使用检测输出机制的方法来表明使用克林霉素是否可能有效。在表皮葡萄球菌和溶血葡萄球菌中，分别有46%和66%的红霉素耐药、克林霉素敏感分离株对克林霉素治疗敏感。
