Showing papers by "Timothy S. Naimi published in 2001"

Epidemiology and clonality of community-acquired methicillin-resistant Staphylococcus aureus in Minnesota, 1996-1998.

Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged among patients in the general population who do not have established risk factors for MRSA. Records from 10 Minnesota health facilities were reviewed to identify cases of MRSA infection that occurred during 1996-1998 and to identify which cases were community acquired. Susceptibility testing and pulsed-field gel electrophoresis (PFGE) subtyping were performed on available isolates. A total of 354 patients (median age, 16 years) with community-acquired MRSA (CAMRSA) infection were identified. Most case patients (299 [84%]) had skin infections, and 103 (29%) were hospitalized. More than 90% of isolates were susceptible to all antimicrobial agents tested, with the exception of beta-lactams and erythromycin. Of 334 patients treated with antimicrobial agents, 282 (84%) initially were treated with agents to which their isolates were nonsusceptible. Of 174 Minnesota isolates tested, 150 (86%) belonged to 1 PFGE clonal group. CAMRSA infections were identified throughout Minnesota; although most isolates were genetically related and susceptible to multiple antimicrobials, they were generally nonsusceptible to initial empirical therapy.

Community-acquired methicillin-resistant Staphylococcus aureus in a rural American Indian community.

Abstract: ContextUntil recently, methicillin-resistant Staphylococcus aureus (MRSA) infections have been acquired primarily in nosocomial settings. Four recent deaths due to MRSA infection in previously healthy children in the Midwest suggest that serious MRSA infections can be acquired in the community in rural as well as urban locations.ObjectivesTo document the occurrence of community-acquired MRSA infections and evaluate risk factors for community-acquired MRSA infection compared with methicillin-susceptible S aureus (MSSA) infection.DesignRetrospective cohort study with medical record review.SettingIndian Health Service facility in a rural midwestern American Indian community.PatientsPatients whose medical records indicated laboratory-confirmed S aureus infection diagnosed during 1997.Main Outcome MeasuresProportion of MRSA infections classified as community acquired based on standardized criteria; risk factors for community-acquired MRSA infection compared with those for community-acquired MSSA infection; and relatedness of MRSA strains, determined by pulsed-field gel electrophoresis (PFGE).ResultsOf 112 S aureus isolates, 62 (55%) were MRSA and 50 (45%) were MSSA. Forty-six (74%) of the 62 MRSA infections were classified as community acquired. Risk factors for community-acquired MRSA infections were not significantly different from those for community-acquired MSSA. Pulsed-field gel electrophoresis subtyping indicated that 34 (89%) of 38 community-acquired MRSA isolates were clonally related and distinct from nosocomial MRSA isolates found in the region.ConclusionsCommunity-acquired MRSA may have replaced community-acquired MSSA as the dominant strain in this community. Antimicrobial susceptibility patterns and PFGE subtyping support the finding that MRSA is circulating beyond nosocomial settings in this and possibly other rural US communities.