Treatment of methicillin-resistant Staphylococcus aureus infections with a minimal inhibitory concentration of 2 µg/mL to vancomycin: old (trimethoprim/sulfamethoxazole) versus new (daptomycin or linezolid) agents.

BACKGROUND: Guidelines recommend that agents other than vancomycin be considered for some types of infection due to methicillin-resistant Staphylococcus aureus (MRSA) when the minimum inhibitory concentration (MIC) to vancomycin is 2 µg/mL or more. Alternative therapeutic options include daptomycin and linezolid, 2 relatively new and expensive drugs, and trimethoprim/sulfamethoxazole (TMP/SMX), an old and inexpensive agent. OBJECTIVE: To compare the clinical efficacy and potential cost savings associated with use of TMP/SMX compared to linezolid and daptomycin. METHODS: A retrospective study was conducted at Detroit Medical Center. For calendar year 2009, unique adults (age >18 years) with infections due to MRSA with an MIC to vancomycin of 2 µg/mL were included if they received 2 or more doses of TMP/SMX and/or daptomycin and/or linezolid. Data were abstracted from patient charts and pharmacy records. RESULTS: There were 328 patients included in the study cohort: 143 received TMP/SMX alone, 89 received daptomycin alone, 75 received linezolid alone, and 21 patients received a combination of 2 or more of these agents. In univariate analysis, patients who received TMP/SMX alone had significantly better outcomes, including in-hospital (p = 0.003) and 90-day mortality (p < 0.001) compared to patients treated with daptomycin or linezolid. Patients receiving TMP/SMX were also younger (p < 0.001), had fewer comorbid conditions (p < 0.001), had less severe acute severity of illness (p < 0.001), and received appropriate therapy more rapidly (p = 0.001). In multivariate models the association between TMP/SMX treatment and mortality was no longer significant. Antimicrobial cost savings associated with using TMP/SMX averaged $2067.40 per patient. CONCLUSIONS: TMP/SMX monotherapy compared favorably to linezolid and daptomycin in terms of treatment efficacy and mortality. Use of TMP/SMX instead of linezolid or daptomycin could potentially significantly reduce antibiotic costs. TMP/SMX should be considered for the treatment of MRSA infection with MIC of 2 µg/mL to vancomycin.

The burden of multidrug-resistant organisms on tertiary hospitals posed by patients with recent stays in long-term acute care facilities.

BACKGROUND: Long-term acute care (LTAC) facilities admit patients with complex, advanced disease states. Study aims were to determine the burden posed on hospitals associated with LTAC exposure and analyze the differences between "present on admission" (POA) multidrug-resistant (MDR), gram-negative organisms (GNO) and POA MDR gram-positive organisms (GPO). METHODS: A multicenter retrospective study was conducted in 13 hospitals from southeast Michigan, from September 1, 2008, to August 31, 2009. Cultures obtained in the first 72 hours of hospitalization (ie, POA) of MDR-GPO and MDR-GNO were reviewed. LTAC exposures in the previous 6 months and direct admission from a LTAC were recorded. RESULTS: Overall, 5,297 patients with 7,147 MDR POA cultures were analyzed: 2,619 (36.6%) were MDR-GNO, and 4,528 (63.4%) were MDR-GPO. LTAC exposure in the past 6 months was present in 251 (5.2%) infectious episodes and was significantly more common among POA MDR-GNO than MDR-GPO (158 [8.6%] and 94 [3.1%], respectively, odds ratio, 2.87; P < .001). Recent LTAC exposure was strongly associated with both carbapenem-resistant Enterobacteriaceae (CRE) (31.6% of all CRE cases, P < .001) and Acinetobacter baumannii (14.9% of all A baumannii cases, P < .001). CONCLUSION: Nearly 10% of MDR-GNO POA had recent LTAC exposure. Hospital efforts to control the spread of MDR-GNO should focus on collaborations and communications with referring LTACs and interventions targeted towards patients with recent LTAC exposure.