Phenotypic expression and genetic heterogeneity of lincosamide inactivation in Staphylococcus spp.

We examined the resistance phenotype and the genetic basis of lincosamide modification in 25 clinical isolates of Staphylococcus spp. inactivating lincomycin and clindamycin. The strains were resistant to high levels of lincomycin but remained susceptible to clindamycin. However, MBCs and inoculum effects showed that the activity of clindamycin was impaired. The distribution in these strains of nucleotide sequences related to linA and linA', the genes encoding lincosamide nucleotidylation in Staphylococcus haemolyticus BM4610 and S. aureus BM4611, respectively, was studied by dot blot hybridization. The genes responsible for lincosamide inactivation in Staphylococcus spp. were found to constitute a family of related sequences which are not species specific.