Rodríguez-Avial C, García M M, Rodríguez-Avial I, Picazo J J
Departamento de Microbiología, Facultad de Medicina, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid.
Rev Esp Quimioter. 1999 Dec;12(4):346-51.
Macrolide resistance has been widely studied in Streptococcus pyogenes and Streptococcus pneumoniae although not in viridans group streptococci (VGS). We studied 30 blood culture isolates of viridans group streptococci (25 resistant to erythromycin: 10 S. mitis, 8 S. milleri, 6 S. sanguis and 1 S. salivarius; and 5 susceptible: 2 S. mitis, 2 S. milleri and 1 S. sanguis). We carried out a double-disk test and determined MICs. The susceptibility testing was carried out by agar dilution for 14-, 15- and 16-member lactone ring macrolides, as well as for clindamycin and quinupristin-dalfopristin. Fifty-six percent of the erithromycin-resistant strains (6 S. mitis, 6 S. milleri and 2 S. sanguis) showed an MLS(B) phenotype, with a high level of intrinsic resistance to all the macrolides studied and clindomycin; 28% were of the M phenotype (4 S. sanguis, 2 S. mitis and 1 S. salivarius). We found a third resistance phenotype, which was present in 4 strains with MICs of 2-8 microg/ml, with resistance to macrolides and different degrees of resistance to clindamycin. All isolates were fully susceptible to quinupristin-dalfopristin. The MLS(B) and M phenotypes initially described in S. pyogenes and S. pneumoniae are also observed in VGS.
虽然尚未对草绿色链球菌（VGS）进行研究，但大环内酯类耐药性已在化脓性链球菌和肺炎链球菌中得到广泛研究。我们研究了30株草绿色链球菌血培养分离株（25株对红霉素耐药：10株缓症链球菌、8株米勒链球菌、6株 sanguis 链球菌和1株唾液链球菌；5株敏感：2株缓症链球菌、2株米勒链球菌和1株 sanguis 链球菌）。我们进行了双纸片试验并测定了最低抑菌浓度（MICs）。通过琼脂稀释法对14、15和16元内酯环大环内酯类药物以及克林霉素和奎奴普丁 - 达福普汀进行药敏试验。56%的红霉素耐药菌株（6株缓症链球菌、6株米勒链球菌和2株 sanguis 链球菌）表现出MLS(B)表型，对所有研究的大环内酯类药物和克林霉素具有高水平的固有耐药性；28%为M表型（4株 sanguis 链球菌、2株缓症链球菌和1株唾液链球菌）。我们发现了第三种耐药表型，存在于4株MIC为2 - 8μg/ml的菌株中，对大环内酯类药物耐药且对克林霉素有不同程度的耐药性。所有分离株对奎奴普丁 - 达福普汀均完全敏感。最初在化脓性链球菌和肺炎链球菌中描述的MLS(B)和M表型在草绿色链球菌中也有观察到。
