A population-based study of the incidence and molecular epidemiology of methicillin-resistant Staphylococcus aureus disease in San Francisco, 2004-2005.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infections have become a major public health problem in both the community and hospitals. Few studies have characterized the incidence and clonal composition of disease-causing strains in an entire population. Our objective was to perform a population-based survey of the clinical and molecular epidemiology of MRSA disease in San Francisco, California. METHODS: We prospectively collected 3985 MRSA isolates and associated clinical and demographic information over a 12-month period (2004-2005) at 9 San Francisco-area medical centers. A random sample of 801 isolates was selected for molecular analysis. RESULTS: The annual incidence of community-onset MRSA disease among San Francisco residents was 316 cases per 100,000 population, compared with 31 cases per 100,000 population for hospital-onset disease. Persons who were aged 35-44 years, were men, and were black had the highest incidence of community-onset disease. The USA300 MRSA clone accounted for 234 cases of community-onset disease and 15 cases of hospital-onset disease per 100,000 population, constituting an estimated 78.5% and 43.4% of all cases of MRSA disease, respectively. Patients with community-onset USA300 MRSA versus non-USA300 MRSA disease were more likely to be male, be of younger age, and have skin and soft-tissue infections. USA300 strains were generally more susceptible to multiple antibiotics, although decreased susceptibility to tetracycline was observed in both community-onset (P = .008) and hospital-onset (P = .03) USA300 compared to non-USA300 strains. CONCLUSIONS: The annual incidence of community-onset MRSA disease in San Francisco is substantial, surpassing that of hospital-onset disease. USA300 is the predominant clone in both the community and hospitals. The dissemination of USA300 from the community into the hospital setting has blurred its distinction as a community-associated pathogen.

Update on D-ala-peptide T-amide (DAPTA): a viral entry inhibitor that blocks CCR5 chemokine receptors.

Peptide T, named for its high threonine content (ASTTTNYT), was derived by a database search which assumed that a relevant receptor binding epitope within env (gp120) would have sequence homology to a known signaling peptide. Binding of radiolabeled gp120 to brain membranes was displaced by peptide T and three octapeptide analogs (including "DAPTA", Dala1-peptide T-amide, the protease-resistant analog now in Phase II clinical trials) with the same potency that these four octapeptides blocked infectivity of an early passage patient isolate. This 1986 report was controversial due to a number of laboratories' failure to find peptide T antiviral effects; we now know that peptide T is a potent HIV entry inhibitor selectively targeting CCR5 receptors with minimal effects on the X4 tropic lab adapted virus exclusively in use at that time. Early clinical trials, which demonstrated lack of toxicity and focused on neurological and neurocognitive benefits, are reviewed and data from a small ongoing Phase II trial--the first to assess peptide T's antiviral effects--are presented. Studies using infectivity, receptor binding, chemotaxis, and blockade of gp120-induced neurotoxicity in vitro and in vivo are reviewed, discussed and presented here. Peptide T and analogs of its core pentapeptide, present near the V2 stem of numerous gp120 isolates, are potent ligands for CCR5. Clinical data showing peptide T's immunomodulation of plasma cytokine levels and increases in the percentage of IFNgamma secreting CD8+ T cells in patients with HIV disease are presented and suggests additional therapeutic mechanisms via regulation of specific immunity.

Antiviral and immunological benefits in HIV patients receiving intranasal peptide T (DAPTA).

D-Ala-Peptide T-amide (DAPTA), the first viral entry inhibitor, blocks chemokine (CCR5) receptors, not CD4. Early investigators could not "replicate" DAPTAs potent in vitro antiviral effect using the lab-adapted, X4, peptide T-insensitive strain, IIIB, delaying clinical virological studies. We now report that DAPTA, administered to eleven long-term infected (mean=17 years) patients with stable persistent plasma "virus" for up to 32 weeks did not change this level. Infectious virus could not be isolated from their plasma suggesting HIV RNA was devoid of replicative capacity. Progressively less actual virus (P<0.01) could be isolated from white blood cells (PBMCs). DAPTA flushed the monocyte reservoir to undetectable viral levels in most patients. Five of eleven had a mean CD4 increase of 33%. Immune benefits also included a four-fold increase in gamma-interferon-secreting T-cells (antiviral cytotoxic T-cells) in the absence of drug-related toxicity. All five CD4 responders had increases in antiviral T cells and decreases in infected monocytes, an argument for initiating further studies promptly.

Micronutrient supplementation increases CD4 count in HIV-infected individuals on highly active antiretroviral therapy: a prospective, double-blinded, placebo-controlled trial.

OBJECTIVE: To examine the immunologic, metabolic, and clinical effects of broad spectrum micronutrient supplementation in HIV-infected patients taking highly active antiretroviral therapy (HAART). DESIGN: A prospective, randomized, double-blinded, placebo-controlled trial. METHODS: Forty HIV-infected patients taking a stavudine and/or didanosine-based HAART regimen were prospectively randomized to receive micronutrients or placebo twice daily for 12 weeks. Data were collected at 4-week intervals including immunologic, metabolic, and clinical measurements. The study examined the effect of micronutrient supplementation on immunologic parameters as the primary end point. The secondary end points were metabolic and clinical effects and distal symmetrical polyneuropathy. RESULTS: The mean absolute CD4 count increased by an average of 65 cells in the micronutrient group versus a 6-cell decline in the placebo group at 12 weeks (P = 0.029). The absolute CD4 count increased by an average of 24% in the micronutrient group versus a 0% change in the placebo group (P = 0.01). The mean HIV-1 RNA decreased in the micronutrient supplementation group, although not significantly. Neuropathy scores improved in the micronutrient group by 42% compared with a 33% improvement in the placebo arm. This difference did not reach statistical significance. Fasting serum glucose, insulin, and lipids were not adversely affected in the patients taking the micronutrients. CONCLUSIONS: Micronutrient supplementation can significantly improve CD4 cell count reconstitution in HIV-infected patients taking HAART. The micronutrient supplement tested was well tolerated and may hold promise as an adjuvant therapy in the treatment of HIV. Further investigation is warranted.

Pharmacokinetic evaluation and short-term activity of stavudine, nevirapine, and nelfinavir therapy in HIV-1-infected adults.

OBJECTIVE: Evaluate pharmacokinetic interaction, short-term safety, and antiretroviral activity of stavudine (d4T), nevirapine (NVP), and nelfinavir (NFV) as combination HIV-1 therapy. DESIGN: Prospective, open-label study investigating the pharmacokinetic interactions between d4T, NVP, and NFV and documenting short-term tolerability and virologic and immunologic activity. METHODS: Twenty-five HIV-1-infected adults, naive to nonnucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs), < or = 6 months of d4T treatment, CD4 > or = 100 cells/mm, and viral load > = 5,000 copies/mL enrolled. All received NFV 750 mg 3 times daily and d4T 30-40 mg twice daily for 1 week, then added NVP at 200 mg once daily for 2 weeks and 200 mg twice daily thereafter. Steady-state pharmacokinetic parameters of NFV, AG1402 (metabolite of NFV), and d4T were compared before and after the addition of NVP. RESULTS: No statistically significant changes in NFV or d4T pharmacokinetics were observed following the addition of NVP. Levels of AG1402 were suppressed 60-70%. Drug-related adverse events were seen at expected rates. At day 36, median viral load suppression was 2.0 log10 and absolute CD4 count increased by 111 cells/mm. CONCLUSIONS: NVP administration did not significantly affect the steady-state pharmacokinetic parameters of NFV or d4T. The combination of d4T, NVP, and NFV induced rapid suppression of HIV-1 viral load and rises in CD4 cell count.