Screening of Novel Inducible Resistance Gene to Macrolide-Lincosamide-Streptogramin B (MLS) Antibiotics from Clinical Isolates of Staphylococcus spp

임상분리 Staphylococcus속 균주로부터 마크로라이드-린코사마이드-스트렙토그라민 B(MLS)계 항생물질에 대한 새로운 유도내성 유전자의 검색

From 84 clinical isolates of Staphylococcus species, ten strains showing inducible resistance to MLS antibiotics were selected by disk agar diffusion method. Colony hybridization was executed using two MLS inducible resistance genes, ermA and ermC, previously identified from S. aureus as probes. S. hemolyticus 401 and S. epidermidis 542 whose genes were not homologous to those probes were finally selected. It was determined that the resistance genes of S. hemolyticus 401 and S. epidermidis 542 were not homologous to ermA, ermC and ermAM by Southern hybridization. S. epidermidis 542 had a plasmid DNA. To know if the plasmid may have genes related to inducible resistance, it was attempted to transform B. subtilis BR151 and S. aureus RN4220 with the plasmid prepared from S. epidermidis 542. It was shown that the gene related to inducible resistance to MLS antibiotics did not exist in this plasmid. These results indicate that two clinical isolates of S. hemolyticus 401 and S. epidermidis 542 had novel genes which were not homologous to MLS resistance genes identified previously. It was assumed that these genes may exist in chromosomal DNA.