title: Prevalence of resistance phenotypes and genotypes to macrolide, lincosamide and streptogramin antibiotics in Gram-positive cocci isolated in Tunisian Bone Marrow Transplant Center.
abstract: To investigate the prevalence of resistance to macrolide, lincosamide and streptogramin (MLS) antibiotics in Gram-positive cocci isolated in a Bone Marrow Transplant Center of Tunisia, we tested the antibiotic susceptibility of 172 clinical isolates of Staphylococcus epidermidis, Streptococcus mitis and Enterococcus faecium to macrolide erythromycin and spiramycin, the lincosamide clindamycin and the streptogramin pristinamycin. These three groups of organisms were mostly resistant to macrolides and lincosamide, but were commonly susceptible to pristinamycin. The resistance phenotypes of erythromycin-resistant isolates were determined by the five-disc test with erythromycin, spiramycin, lincomycin, clindamycin and pristinamycin, which showed that most exhibited constitutive MLS resistance. In order to determine the prevalence of the resistance genotypes and the resistance mechanisms, the prevalence of the erythromycin resistance methylase (erm) (A), erm(B), erm(C), msr(A) and macrolide efflux (mef) (A) genes in the erythromycin-resistant isolates was identified by polymerase chain reaction (PCR) analysis. The resistance was due mainly to the presence of ermB in E. faecium (80%), ermC in S. epidermidis (53%) and mefA in S. mitis (65%).
authors.affiliation: Laboratoire du Centre National de Greffe de Moelle Osseuse, 1006 Tunis, Tunisia. onsboucham@yahoo.fr
authors.forename: O
authors.initials: O
authors.lastname: Bouchami
authors.forename: W
authors.initials: W
authors.lastname: Achour
authors.forename: A
authors.initials: A
authors.lastname: Ben Hassen
mesh_terms: D016026:Bone Marrow Transplantation; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial / Q000235:genetics; D016984:Enterococcus faecium / Q000187:drug effects; D005838:Genotype; D006095:Gram-Positive Cocci / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D055231:Lincosamides / Q000494:pharmacology*; D018942:Macrolides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D013212:Staphylococcus epidermidis / Q000187:drug effects; D034361:Streptococcus mitis / Q000187:drug effects; D025361:Streptogramins / Q000494:pharmacology*; D014416:Tunisia
chemical_list: D004269:DNA, Bacterial; D055231:Lincosamides; D018942:Macrolides; D025361:Streptogramins