title: In vitro antimicrobial findings for fusidic acid tested against contemporary (2008-2009) gram-positive organisms collected in the United States.
abstract: Fusidic acid has a long history of consistent activity against staphylococcal pathogens including methicillin-resistant Staphylococcus aureus (MRSA). Fusidic acid (CEM-102) was susceptibility tested against a surveillance study collection of 12,707 Gram-positive pathogens (2008-2009) from the United States. Reference broth microdilution method results demonstrated the following MIC(50/90) results: S. aureus (.12/.25 μg/mL), coagulase-negative staphylococci (.12/.25 μg/mL), enterococci (4/4 μg/mL), Streptococcus pyogenes (4/8 μg/mL), and viridans group Streptococcus spp. (>8/>8 μg/mL). At a proposed susceptible breakpoint (≤1 μg/mL), fusidic acid inhibited 99.7% of MRSA strains and 99.3% to 99.9% of multidrug-resistant phenotypes of S. aureus. Furthermore, S. aureus strains nonsusceptible to fusidic acid (.35%) generally had detectable resistance mechanisms (fusA, B, C, and E). Reviews of in vitro susceptibility test development confirm the accuracy and intermethod reproducibility of various fusidic acid methods. Fusidic acid is a promising oral therapy for staphylococcal skin and skin structure infections in the United States, where the contemporary S. aureus population remains without significant resistance.
authors.affiliation: JMI Laboratories, North Liberty, Iowa, USA. ronald-jones@jmilabs.com
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
authors.forename: Rodrigo E
authors.initials: RE
authors.lastname: Mendes
authors.forename: Helio S
authors.initials: HS
authors.lastname: Sader
authors.forename: Mariana
authors.initials: M
authors.lastname: Castanheira
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005672:Fusidic Acid / Q000737:chemistry / Q000494:pharmacology*; D006095:Gram-Positive Cocci / Q000187:drug effects*; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests / Q000592:standards; D011159:Population Surveillance / Q000379:methods*; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D013210:Staphylococcus / Q000187:drug effects; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D005672:Fusidic Acid