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.

Fluconazole-resistant Candida albicans vulvovaginitis.

OBJECTIVE: As a result of high recurrence rates of Candida albicans vaginitis, successful suppressive fluconazole is widely used, and drug resistance is considered rare. We report increased occurrence of secondary fluconazole resistance, analysis of risk factors thereof, and describe management of fluconazole-refractory vaginitis. METHODS: Patients referred to the Vaginitis Clinic at Wayne State University with clinically refractory fluconazole-resistant (minimum inhibitory concentration [MIC] 2 micrograms/mL or greater) C albicans vaginitis from 2000 to 2010 were enrolled. Patients completed a questionnaire pertaining to demographics, comorbidities, behavioral characteristics, exposure to antimicrobials and antifungals, fluconazole consumption in defined daily doses in the previous 6 months, management received, and outcomes. With patients not located, data were extracted from charts. Susceptibilities to antifungals were determined by broth microdilution. RESULTS: Twenty-five women with fluconazole-resistant recurrent C albicans vaginitis were identified, and 16 returned filled questionnaires. Study cohort consisted mainly of married, insured white women with more than 12 years of formal education and average or above average socioeconomic status. Median fluconazole MIC was 8 micrograms/mL (range 2-128 micrograms/mL). Risk factors for mycologic failure included increased fluconazole consumption (P=.03) with 16 of 25 women exposed to low-dose weekly fluconazole maintenance therapy. All patients were clinically controlled successfully, although treatment was difficult and often prolonged. CONCLUSION: Fluconazole-resistant C albicans vaginitis was previously considered rare. We report 25 cases over an 11-year period, indicating an emerging problem. All patients had fluconazole consumption in the previous 6 months. Management of fluconazole refractory disease is extremely difficult with limited options, and new therapeutic modalities are needed.

Efficacy of ertapenem for treatment of bloodstream infections caused by extended-spectrum-ß-lactamase-producing Enterobacteriaceae.

Ertapenem is active against extended-spectrum-ß-lactamase (ESBL)-producing Enterobacteriaceae organisms but inactive against Pseudomonas aeruginosa and Acinetobacter baumannii. Due to a lack of therapeutic data for ertapenem in the treatment of ESBL bloodstream infections (BSIs), group 2 carbapenems (e.g., imipenem or meropenem) are often preferred for treatment of ESBL-producing Enterobacteriaceae, although their antipseudomonal activity is unnecessary. From 2005 to 2010, 261 patients with ESBL BSIs were analyzed. Outcomes were equivalent between patients treated with ertapenem and those treated with group 2 carbapenems (mortality rates of 6% and 18%, respectively; P = 0.18).

Detection of oseltamivir resistance during treatment of 2009 H1N1 influenza virus infection in immunocompromised patients: utility of cycle threshold values of qualitative real-time reverse transcriptase PCR.

Two immunocompromised patients with 2009 H1N1 influenza pneumonia had viral shedding for over 5 weeks despite therapy with oseltamivir. Declining or persistently low cycle threshold values noted on serial qualitative real-time reverse transcriptase PCR (rRT-PCR) of respiratory specimens implied increasing viral load and probable drug resistance. Oseltamivir resistance was later confirmed by pyrosequencing.