title: Antibiotic resistance assessment in S. aureus strains isolated from raw sheep's milk cheese.
abstract: In vitro activities of 16 antibiotics were tested against 36 Staphylococcus aureus (SA) strains isolated from raw sheep's milk cheese from six dairies. The minimum inhibitory concentration (MIC) was determined using a broth microdilution method (CLSI). All 36 isolates were analyzed for the presence of the accessory gene regulator gene, agr (I-IV), and genes encoding resistance to methicillin (mecA), erythromycin (ermA), penicillin (blaZ), and vancomycin (vanA-B). The isolates were also analyzed for similarities in pulsed-field gel electrophoresis (PFGE) patterns. SA strains showed resistance to ampicillin (36.1%), penicillin (33.3%), tetracycline (11.1%), and cloxacillin (2.8%) but were susceptible (>or=94.4%) to 12 out of 16 tested antimicrobials. The overall susceptibility of the strains to oxacillin, vancomycin, and erythromycin was confirmed by the absence of the mecA, vanA-B, and ermA genes. The PFGE results showed that 32 strains belonged to 10 different clusters (P1-P10) while four strains were untypeable.
authors.affiliation: Dipartimento di Biologia Animale, Facoltà di Medicina Veterinaria, Sassari, Italy. vspanu@uniss.it
authors.forename: V
authors.initials: V
authors.lastname: Spanu
authors.forename: S
authors.initials: S
authors.lastname: Virdis
authors.forename: C
authors.initials: C
authors.lastname: Scarano
authors.forename: F
authors.initials: F
authors.lastname: Cossu
authors.forename: E P L
authors.initials: EP
authors.lastname: De Santis
authors.forename: A M
authors.initials: AM
authors.lastname: Cosseddu
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002611:Cheese / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D005516:Food Microbiology; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology*; D012756:Sheep; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents