Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteremia/drug therapy , Daptomycin/pharmacology , Drug Resistance, Multiple, Bacterial/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Staphylococcal Infections/drug therapy , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Bacteremia/diagnosis , Cohort Studies , Daptomycin/therapeutic use , Drug Resistance, Multiple, Bacterial/physiology , Female , Follow-Up Studies , Humans , Male , Methicillin-Resistant Staphylococcus aureus/physiology , Middle Aged , Staphylococcal Infections/diagnosis , Treatment OutcomeABSTRACT
There is increasing concern regarding the association between certain methicillin-resistant Staphylococcus aureus (MRSA) genotypes and poor clinical outcome. To assess this issue, a large cohort of 579 subjects with MRSA bacteraemia was prospectively followed from June 2008 to December 2009, in 21 hospitals in Spain. Epidemiology, clinical data, therapy, and outcome were recorded. All MRSA strains were analysed in a central laboratory. Presence of a haematogenous seeding infection was the dependent variable in an adjusted logistic regression model. Of the 579 patients included in the study, 84 (15%) had haematogenous seeding infections. Microdilution vancomycin median MIC (IQR) was 0.73 (0.38-3) mg/L. Most MRSA isolates (n = 371; 67%) belonged to Clonal Complex 5 (CC5) and carried an SCCmec element type IV and agr type 2. Isolates belonging to ST8-agr1-SCCmecIV, ST22-agr1-SCCmecIV and ST228-agr2-SCCmecI--a single locus variant of ST5--accounted for 8%, 9% and 9% of the isolates, respectively. After adjusting by clinical variables, any of the clones was associated with increased risk of haematogenous seeding infections. Higher vancomycin MIC was not identified as an independent risk factor, either. In contrast, persistent bacteraemia (OR 4.2; 2.3-7.8) and non-nosocomial acquisition (3.0; 1.7-5.6) were associated with increased risk.
Subject(s)
Bacteremia/microbiology , Cross Infection/microbiology , Methicillin-Resistant Staphylococcus aureus/classification , Methicillin-Resistant Staphylococcus aureus/genetics , Staphylococcal Infections/microbiology , Adolescent , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Bacteremia/drug therapy , Bacteremia/epidemiology , Bacteremia/mortality , Cross Infection/drug therapy , Cross Infection/epidemiology , Cross Infection/mortality , Female , Genotype , Hospitals , Humans , Male , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Microbial Sensitivity Tests , Middle Aged , Molecular Typing , Prospective Studies , Spain , Staphylococcal Infections/drug therapy , Staphylococcal Infections/epidemiology , Staphylococcal Infections/mortality , Survival Analysis , Treatment Outcome , Vancomycin/pharmacology , Young AdultABSTRACT
Methicillin-resistant Staphylococcus aureus (MRSA) is highly prevalent in Spanish hospitals and community long-term-care facilities (LTCFs). This longitudinal study was performed in community LTCFs to determine whether MRSA colonization is associated with MRSA infections and overall mortality. Nasal and decubitus ulcer cultures were performed every 6 months for an 18-month period on 178 MRSA-colonized residents (86 490 patient-days) and 196 non-MRSA carriers (97 470 patient-days). Fourteen residents developed MRSA infections and 10 of these were skin and soft tissue infections. Two patients with respiratory infections required hospitalization. The incidence rate of MRSA infection was 0·12/1000 patient-days in MRSA carriers and 0·05/1000 patient-days in non-carriers (P=0·46). No difference in MRSA infection rate was found according to the duration of MRSA colonization (P=0·69). The mortality rate was 20·8% in colonized residents and 16·8% in non-carriers; four residents with MRSA infection died. Overall mortality was statistically similar in both cohorts. Our results suggest that despite a high prevalence of MRSA colonization in LTCFs, MRSA infections are neither frequent nor severe while colonized residents remain at the facility. The epidemiological impact of an MRSA reservoir is more relevant than the clinical impact of this colonization for an individual resident and supports current recommendations to control MRSA spread in community LTCFs.
