title: Agar dilution and agar screen with cefoxitin and oxacillin: what is known and what is unknown in detection of meticillin-resistant Staphylococcus aureus.
abstract: In this study we evaluated the performance of the oxacillin agar screen test, and agar dilution tests using cefoxitin and oxacillin antimicrobials, to detect meticillin resistance in Staphylococcus aureus isolates. The presence of the mecA gene, detected by PCR, was used as the standard to which agar screen and agar dilution tests were compared. The best performance was obtained using the agar dilution test (99.4 % accuracy) with breakpoints of 4 mug ml(-1) for oxacillin and 8 mug ml(-1) for cefoxitin, and using the oxacillin agar screen test. Also, a strong correlation between MIC values of cefoxitin and oxacillin permits the use of either drug for detection of meticillin resistance.
authors.affiliation: Laboratory of Microbiology, Hospital Mãe de Deus, Porto Alegre, RS, Brazil.|Post-Graduate Program in Medical Sciences, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, RS, Brazil.
authors.forename: Leandro Reus Rodrigues
authors.initials: LRR
authors.lastname: Perez
authors.affiliation: Microbiology Department, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Porto Alegre, RS, Brazil.|Laboratory of Microbiology, Hospital Mãe de Deus, Porto Alegre, RS, Brazil.
authors.forename: Cícero
authors.initials: C
authors.lastname: Dias
authors.affiliation: Microbiology Department, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Porto Alegre, RS, Brazil.|Post-Graduate Program in Medical Sciences, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, RS, Brazil.
authors.forename: Pedro Alves
authors.initials: PA
authors.lastname: d'Azevedo
mesh_terms: D000362:Agar; D002440:Cefoxitin / Q000494:pharmacology*; D006801:Humans; D007297:Inpatients; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D010068:Oxacillin / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D002440:Cefoxitin; D000362:Agar; D010068:Oxacillin