Westh H, Hougaard D M, Vuust J, Rosdahl V T
Department of Clinical Microbiology, University of Copenhagen, Rigshospitalet, Denmark.
APMIS. 1995 Mar;103(3):225-32.
Erythromycin-resistant S. aureus from general practice and a dermatology ward with a very high consumption of erythromycin was studied for ermA and ermC content by Southern blot analysis. The prevalence of these erm genes was also studied in coagulase-negative staphylococci from the same dermatology ward and in a collection of 15 S. aureus and 18 coagulase-negative staphylococci found in the same specimen from 15 different patients. ermA was only found as a chromosomal insert and ermC only on small plasmids. In erythromycin-resistant S. aureus from general practice ermC was responsible for 84% of erythromycin resistance, while 16% of the strains contained ermA. In 17 of 18 S. aureus strains from the dermatology ward a 2.5 kb plasmid contained ermC. Among 58 erythromycin-resistant coagulase-negative staphylococci only 2 (3%) had ermA, whereas 44 strains (76%) had ermC. ermA or ermC genes were common in S. epidermidis (36/38). However, in 20 isolates of erythromycin-resistant coagulase-negative staphylococci of other species, 10 had neither ermA nor ermC. ermC was the most common erm gene in both coagulase-negative staphylococci and S. aureus. In 11 of 15 patients with erythromycin-resistant S. aureus the co-isolated erythromycin-resistant coagulase-negative staphylococcus had another resistance mechanism, either another gene or a different phenotypic expression of the same gene. Resistance to pristinamycin, a streptogramin antibiotic only used in animals, was not found in S. aureus but was found in 14% of erythromycin-resistant coagulase-negative staphylococci.
通过Southern印迹分析，对来自普通诊所和皮肤科病房（该病房红霉素消耗量极高）的耐红霉素金黄色葡萄球菌进行了ermA和ermC含量研究。还对来自同一皮肤科病房的凝固酶阴性葡萄球菌以及从15名不同患者的同一标本中分离出的15株金黄色葡萄球菌和18株凝固酶阴性葡萄球菌中这些erm基因的流行情况进行了研究。ermA仅作为染色体插入片段被发现，而ermC仅存在于小质粒上。在来自普通诊所的耐红霉素金黄色葡萄球菌中，ermC导致了84%的红霉素耐药，而16%的菌株含有ermA。在皮肤科病房的18株金黄色葡萄球菌菌株中，有17株的一个2.5kb质粒含有ermC。在58株耐红霉素凝固酶阴性葡萄球菌中，只有2株（3%）含有ermA，而44株（76%）含有ermC。ermA或ermC基因在表皮葡萄球菌中很常见（36/38）。然而，在20株耐红霉素的其他种凝固酶阴性葡萄球菌分离株中，有10株既没有ermA也没有ermC。ermC是凝固酶阴性葡萄球菌和金黄色葡萄球菌中最常见的erm基因。在15例耐红霉素金黄色葡萄球菌患者中，有11例共同分离出的耐红霉素凝固酶阴性葡萄球菌具有另一种耐药机制，要么是另一个基因，要么是同一基因的不同表型表达。在金黄色葡萄球菌中未发现对仅用于动物的链阳菌素类抗生素普那霉素的耐药性，但在14%的耐红霉素凝固酶阴性葡萄球菌中发现了这种耐药性。
