title: Activity of ceftaroline and epidemiologic trends in Staphylococcus aureus isolates collected from 43 medical centers in the United States in 2009.
abstract: A Staphylococcus aureus surveillance program was initiated in the United States to examine the in vitro activity of ceftaroline and epidemiologic trends. Susceptibility testing by Clinical and Laboratory Standards Institute broth microdilution was performed on 4,210 clinically significant isolates collected in 2009 from 43 medical centers. All isolates were screened for mecA by PCR and evaluated by pulsed-field gel electrophoresis. Methicillin-resistant S. aureus (MRSA) were analyzed for Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosome mec (SCCmec) type. All isolates had ceftaroline MICs of ≤2 μg/ml with an MIC(50) of 0.5 and an MIC(90) of 1 μg/ml. The overall resistance rates, expressed as the percentages of isolates that were intermediate and resistant (or nonsusceptible), were as follows: ceftaroline, 1.0%; clindamycin, 30.2% (17.4% MIC ≥ 4 μg/ml; 12.8% inducible); daptomycin, 0.2%; erythromycin, 65.5%; levofloxacin, 39.9%; linezolid, 0.02%; oxacillin, 53.4%; tetracycline, 4.4%; tigecycline, 0%; trimethoprim-sulfamethoxazole, 1.6%; vancomycin, 0%; and high-level mupirocin, 2.2%. The mecA PCR was positive for 53.4% of the isolates. The ceftaroline MIC(90)s were 0.25 μg/ml for methicillin-susceptible S. aureus and 1 μg/ml for MRSA. Among the 2,247 MRSA isolates, 51% were USA300 (96.9% PVL positive, 99.7% SCCmec type IV) and 17% were USA100 (93.4% SCCmec type II). The resistance rates for the 1,137 USA300 MRSA isolates were as follows: erythromycin, 90.9%; levofloxacin, 49.1%; clindamycin, 7.6% (6.2% MIC ≥ 4 μg/ml; 1.4% inducible); tetracycline, 3.3%; trimethoprim-sulfamethoxazole, 0.8%; high-level mupirocin, 2.7%; daptomycin, 0.4%; and ceftaroline and linezolid, 0%. USA300 is the dominant clone causing MRSA infections in the United States. Ceftaroline demonstrated potent in vitro activity against recent S. aureus clinical isolates, including MRSA, daptomycin-nonsusceptible, and linezolid-resistant strains.
authors.affiliation: Department of Clinical Pathology, Cleveland Clinic, 9500 Euclid Avenue, L40, Cleveland, OH 44195, USA. richtes@ccf.org
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Richter
authors.forename: Kristopher P
authors.initials: KP
authors.lastname: Heilmann
authors.forename: Cassie L
authors.initials: CL
authors.lastname: Dohrn
authors.forename: Fathollah
authors.initials: F
authors.lastname: Riahi
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Costello
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Kroeger
authors.forename: Donald
authors.initials: D
authors.lastname: Biek
authors.forename: Ian A
authors.initials: IA
authors.lastname: Critchley
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Diekema
authors.forename: Gary V
authors.initials: GV
authors.lastname: Doern
mesh_terms: D000081:Acetamides / Q000494:pharmacology; D001427:Bacterial Toxins / Q000235:genetics; D002511:Cephalosporins / Q000494:pharmacology*; D002981:Clindamycin / Q000494:pharmacology; D017576:Daptomycin / Q000494:pharmacology; D016521:Electrophoresis, Gel, Pulsed-Field; D004917:Erythromycin / Q000494:pharmacology; D005098:Exotoxins / Q000235:genetics; D007956:Leukocidins / Q000235:genetics; D064704:Levofloxacin; D000069349:Linezolid; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D016712:Mupirocin / Q000494:pharmacology; D015242:Ofloxacin / Q000494:pharmacology; D010068:Oxacillin / Q000494:pharmacology; D023303:Oxazolidinones / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics; D013752:Tetracycline / Q000494:pharmacology; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014481:United States; D014640:Vancomycin / Q000494:pharmacology; D000097583:Ceftaroline
chemical_list: D000081:Acetamides; D001427:Bacterial Toxins; D002511:Cephalosporins; D002981:Clindamycin; D017576:Daptomycin; D004917:Erythromycin; D005098:Exotoxins; D007956:Leukocidins; D064704:Levofloxacin; D000069349:Linezolid; D016712:Mupirocin; D015242:Ofloxacin; D010068:Oxacillin; D023303:Oxazolidinones; D013752:Tetracycline; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D014640:Vancomycin; D000097583:Ceftaroline; C078284:Panton-Valentine leukocidin