Different formulations of vancomycin: In vitro antimicrobial activity against clinical isolates of methicillin-resistant Staphylococcus aureus.

We compared in vitro antimicrobial activity of four vancomycin formulations used clinically against clinical isolates of Staphylococcus aureus, including methicillin-resistant and -susceptible (MRSA and MSSA, respectively), using different susceptibility assays. The minimal inhibitory concentrations (MICs) against MRSA clinical isolates were significantly different for some vancomycin formulations by the broth microdilution and agar dilution methods. However, these variations would not compromise their clinical use, since the MICs were within the range recommended by the Clinical and Laboratory Standards Institute. Furthermore, 26.9% of MRSA clinical isolates showed a vancomycin MIC ≥1.5 µg/mL according to the Etest® method but none by broth microdilution. Regarding quality, all formulations were in accordance with United States Pharmacopeia criteria. Our results showed that all vancomycin formulations tested showed similar in vitro antimicrobial activity, making them suitable for clinical use, and that the evaluation method chosen to determine sensitivity to this antimicrobial should be carefully performed, particularly for MRSA.

Treating Staphylococcus aureus infections in an intensive care unit at a University Hospital in Brazil.

BACKGROUND: Optimizing antimicrobial therapy is important for treating patients who are critically ill with Staphylococcus aureus infection, and susceptibility tests are necessary. OBJECTIVE: The aim of the present study was to evaluate antibacterial therapy after susceptibility testing of S. aureus infections. Setting The setting was an intensive care unit at a University Hospital in Brazil. METHODS: An observational and retrospective study was conducted over 6 years. The antimicrobials that were used for S. aureus infection treatment were calculated as the defined daily dose per 1000 patient-days (DDD1000). Antimicrobial susceptibility data were obtained by reviewing bacteriological tests. Patient profiles and treatment were determined by analyzing patient charts. RESULTS: Methicillin-resistant S. aureus (MRSA) was prevalent in this study (76.13 %). Patients who were infected with MRSA had total antimicrobial consumption that was three-times higher (9567.2 DDD1000) than patients who were infected with methicillin-susceptible S. aureus (MSSA; 3101.1 DDD1000). The average length of stay in the intensive care unit was 19 days (interquartile range 17 days) for MSSA and 20 days (interquartile range 20 days) for MRSA. Mortality in patients who were infected with MSSA was higher (52.17 %) than in patients who were infected with MRSA (33.80 %), and de-escalation was not identified in 73.90 % of MSSA patients.

Utilization of fluconazole in an intensive care unit at a university hospital in Brazil.

BACKGROUND: Fungi have been developing resistance and merit greater attention because these microorganisms are among the major causes of hospital infection. OBJECTIVE: The aim of the present study was to characterize the pattern of fluconazole use in an adult intensive care unit. SETTING: The setting was an intensive care unit at a university hospital in Brazil. METHOD: An observational retrospective study was performed between 2007 and 2010. The use of antifungal drugs was calculated as the defined daily dose per 1,000 patient-days. The pattern of fluconazole use was determined by analyzing patient charts. RESULTS: Fluconazole accounted an average of 66.6 % of the antifungal agents prescribed. All of the patients exhibited important risk factors for the development of fungal infection. Treatment was empirical in 45.2 % of the cases and therapeutic in 54.8 % of the cases. The dose interval was inadequate in 51.1 % of the treatments. Fluconazole at doses ≥400 mg/day was related to a greater likelihood of survival. C. albicans was the most prevalent species (31.3 %). Urine was the biological material with the greatest number of positive mycological exams (71.9 %). CONCLUSION: This study found a high utilization of fluconazole and, in most cases, its administration at intervals that were different from the recommended intervals.