title: Trends in prescribing beta-lactam antibiotics for treatment of community-associated methicillin-resistant Staphylococcus aureus infections.
abstract: Rates of prescribing of beta-lactam antibiotics as initial empirical therapy for patients with skin and soft tissue infections (SSTIs) caused by molecularly and epidemiologically characterized community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates were assessed over a 3-year period. A prospectively developed database was used to calculate the prevalence of CA-MRSA SSTIs from 2004 to 2006. Molecular characterization of the MRSA isolate and medical record review for assessment of initial antimicrobial therapy were performed on a subset of patients. Among 2,636 patients with S. aureus SSTIs, the prevalence of CA-MRSA was 9% in 2004, 16% in 2005, and 21% in 2006 (P < 0.0001, chi-square test for trend). Seventy-five percent of CA-MRSA isolates tested were of the USA 300 or 400 clone type. Ninety-two percent of CA-MRSA isolates tested were positive for Panton-Valentine leukocidin, of which 90% carried staphylococcal chromosomal cassette mec type IV. The rate of use of a beta-lactam antibiotic as initial empirical therapy for patients with CA-MRSA SSTIs was 86%, 77%, and 60% in 2004, 2005, and 2006, respectively (P = 0.04, chi-square test for trend). Thirty percent of beta-lactam-treated patients had a documented risk factor for CA-MRSA infection. The use of a beta-lactam antibiotic as initial empirical therapy for CA-MRSA SSTIs has decreased significantly over the past 3 years. However, even as the prevalence of CA-MRSA SSTIs approaches 25%, the majority of patients are still receiving inactive antimicrobial therapy. Further evaluation of the outcomes associated with discordant therapy for CA-MRSA SSTIs is needed.
authors.affiliation: Department of Medicine, VA Connecticut Health Care System, West Haven, CT, USA. Kalpana.gupta@va.gov
authors.forename: Kalpana
authors.initials: K
authors.lastname: Gupta
authors.forename: Ann
authors.initials: A
authors.lastname: Macintyre
authors.forename: Gary
authors.initials: G
authors.lastname: Vanasse
authors.forename: Louise-Marie
authors.initials: LM
authors.lastname: Dembry
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D006302:Health Services Research; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016106:Methicillin Resistance / Q000235:genetics*; D008875:Middle Aged; D015995:Prevalence; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D014481:United States; D047090:beta-Lactams / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams