title: Relative susceptibilities to vancomycin and quinupristin-dalfopristin of adhered and planktonic vancomycin-resistant and vancomycin-susceptible coagulase-negative staphylococci.
abstract: Quinupristin-dalfopristin, a novel streptogramin antibiotic, has proven efficacious against multi-drug-resistant, Gram-positive bacteria, particularly glycopeptide-resistant coagulase-negative staphylococci (CoNS), and CoNS within biofilms. We examined its activity, along with the glycopeptide antibiotic vancomycin, against laboratory-derived, vancomycin-resistant (van R) CoNS and their vancomycin-susceptible (van S) parent strains, both in the planktonic state and after their adhesion to silicone urinary catheters. The laboratory-derived van R CoNS displayed lower adhesion and biofilm formation capabilities than did their van S parent strains. Compared with silicone, the adhesion to hydrogel-silver urinary catheters was approximately one log lower for both van R and van S CoNS. Adhesion of van R and van S CoNS to silicone catheters increased their tolerance to vancomycin. However, adhered van R CoNS succumbed to concentrations of quinupristin-dalfopristin markedly (16- to 32-fold) lower than adhered van S CoNS. This anomaly may be due to the presence of vancomycin sequestered in the cell wall of van R CoNS. Quinupristin-dalfopristin in combination with vancomycin may provide enhanced inhibitory effects against van R CoNS in the adhered state.
authors.affiliation: Georgia State University, Department of Biology, 24 Peachtree Center Avenue, 402 Kell Hall, Atlanta, Georgia 30303, USA.
authors.forename: Deanine G
authors.initials: DG
authors.lastname: Halliman
authors.forename: Donald G
authors.initials: DG
authors.lastname: Ahearn
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002404:Catheterization; D003030:Coagulase / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D020100:Hydrogels; D016106:Methicillin Resistance / Q000235:genetics; D008826:Microbial Sensitivity Tests; D012828:Silicones; D013210:Staphylococcus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D014640:Vancomycin / Q000494:pharmacology*; D020713:Vancomycin Resistance; D014769:Virginiamycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D003030:Coagulase; D020100:Hydrogels; D012828:Silicones; D014769:Virginiamycin; C062940:quinupristin-dalfopristin; D014640:Vancomycin