Conjugative transfer of drug resistance from Russian MRSA strains to S. aureus RN2677.

aGroups of MRSA strains from Russia are from Table 1.bDrug resistance genes acquired by transconjugants are shown in parentheses (cat, chloramphenicol resistance; ermA, erythromycin and clindamycin resistance; aacA-aphD, gentamicin and kanamycin resistance; tetM, tetracycline and minocycline resistance; cadA, cadmium resistance; −, no previously-described sequences). Plasmid size was described after the resistance gene in parentheses.cDonor MRSA strains were susceptible to each drug (resulting in no transconjugants).dResistance transfer frequencies (average data in two or three experiments) for four group2 isolates were 1.4×10−2, 6.5×10−3, 1.0×10−3, and 5.3×10−4.e, f, gStrain 2H; 105H; and 102H, 103H, and 104H, respectively.