A number of research studies have attempted to translate the behavioral lifestyle intervention delivered in the Diabetes Prevention Program (DPP). To compare the active interventions of two trials, Diabetes Prevention Program DPP and Healthy Living Partnerships to Prevent Diabetes (HELP PD), after 1 and 2 years of intervention. DPP included 3234 adults with prediabetes randomized to intensive lifestyle intervention, metformin, troglitazone, or placebo.
View Article and Find Full Text PDFEarly attempts to improve BCG have focused on increasing the expression of prominent antigens and adding recombinant toxins or cytokines to influence antigen presentation. One such modified BCG vaccine candidate has been withdrawn from human clinical trials due to adverse effects. BCG was derived from virulent Mycobacterium bovis and retains much of its capacity for suppressing host immune responses.
View Article and Find Full Text PDFTo identify factors contributing to the ability of tubercle bacilli to grow in the lung during active infection, we analyzed RNA expression patterns in bacteria present in patient sputum. Prominent among bacterial transcripts identified were those encoding secreted peptides of the Esat-6 subfamily that includes EsxK and EsxL (Rv1197 and Rv1198). H37Rv esxKL and esxJI transcripts were differentially expressed under different growth conditions, and disruption of these genes altered growth phase kinetics in typical laboratory batch broth cultures.
View Article and Find Full Text PDFMutations that arose in bacille Calmette-Guérin (BCG) daughter strains during decades of in vitro cultivation have long been suspected of reducing the efficacy of the BCG vaccine against pulmonary tuberculosis. Although concern was raised 6 decades ago that BCG had become overattenuated, preferential use of relatively virulent BCG vaccines has not restored efficacy. The recent discovery that as BCG evolved its production of antioxidants increased as a consequence of genomic duplications and other mutations suggests the alternative hypothesis that BCG became better at suppressing oxidant-dependent immune responses.
View Article and Find Full Text PDFBackground: Current laboratory methods for monitoring the response to therapy for tuberculosis (TB) rely on mycobacterial culture. Their clinical usefulness is therefore limited by the slow growth rate of Mycobacterium tuberculosis. Rapid methods to reliably quantify the response to anti-TB drugs are desirable.
View Article and Find Full Text PDFBackground: In early clinical studies, the live tuberculosis vaccine Mycobacterium bovis BCG exhibited 80% protective efficacy against pulmonary tuberculosis (TB). Although BCG still exhibits reliable protection against TB meningitis and miliary TB in early childhood it has become less reliable in protecting against pulmonary TB. During decades of in vitro cultivation BCG not only lost some genes due to deletions of regions of the chromosome but also underwent gene duplication and other mutations resulting in increased antioxidant production.
View Article and Find Full Text PDFBackground: Prior studies, including one from our institution performed in 2001, suggest that nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) occurs infrequently in the healthy pediatric population (0.2-2.2%).
View Article and Find Full Text PDFObjective: To determine whether a computerized decision support system could increase the proportion of oral quinolone antibiotic orders placed for hospitalized patients.
Design: Prospective, interrupted time-series analysis.
Setting: University hospital in the south-eastern United States.
Background: It has been hypothesized that certain Mycoplasma species may cause Gulf War veterans' illnesses (GWVIs), chronic diseases characterized by pain, fatigue, and cognitive symptoms, and that affected patients may benefit from doxycycline treatment.
Objective: To determine whether a 12-month course of doxycycline improves functional status in Gulf War veterans with GWVIs.
Design: A randomized, double-blind, placebo-controlled clinical trial with 12 months of treatment and 6 additional months of follow-up.
We examined the role of redox signaling generated by NADPH oxidase in activation of NF-kappaB and host defense against Pseudomonas aeruginosa pneumonia. Using mice with an NF-kappaB-driven luciferase reporter construct (HIV-LTR/luciferase (HLL)), we found that intratracheal administration of P. aeruginosa resulted in a dose-dependent neutrophilic influx and activation of NF-kappaB.
View Article and Find Full Text PDFAdherence of Staphylococcus aureus to host tissues is a critical step for colonization and initiation of infection. The fibronectin-binding proteins (FnBPs) of S. aureus have been implicated in adherence and internalization in nonprofessional phagocytes.
View Article and Find Full Text PDFAm J Respir Crit Care Med
December 2001
Superoxide dismutase (SOD) is a ubiquitous metalloenzyme in aerobic organisms that catalyzes the conversion of superoxide anion to hydrogen peroxide. Mycobacterium tuberculosis is unusual in that it secretes large quantities of iron-cofactored SOD. To determine the role of SOD in pathogenesis, we constructed mutants of M.
View Article and Find Full Text PDFMost studies of human T-cell responses in tuberculosis have focused on persons with either active disease or latent infection. Although this work has been critical in defining T-cell correlates of successful versus failed host containment, little is known about the development of Mycobacterium-specific T-cell responses in uninfected persons. To explore this issue, naive T cells from uninfected donors were sensitized in vitro with avirulent Mycobacterium tuberculosis-infected autologous macrophages.
View Article and Find Full Text PDFA major obstacle to development of subunit vaccines and diagnostic reagents for tuberculosis is the inability to produce large quantities of these proteins. To test the hypothesis that poor expression of some mycobacterial genes in Escherichia coli is due, in part, to the presence of low-usage E. coli codons, we used site-directed mutagenesis to convert low-usage codons to high-usage codons for the same amino acid in the Mycobacterium tuberculosis genes for antigens 85A and 85B and superoxide dismutase.
View Article and Find Full Text PDFAntimicrob Agents Chemother
December 1998
In contrast to most Staphylococcus aureus isolates in which the gene for staphylococcal beta-lactamase (blaZ) is plasmid borne, isolates typeable by group II bacteriophages frequently carry blaZ on the chromosome. Furthermore, the chromosomal gene encodes the type B variant of staphylococcal beta-lactamase for which the nucleotide and deduced amino acid sequences have not yet been reported. To better understand beta-lactamase production among phage group II staphylococci and the nature of the type B beta-lactamase, we determined the type and amount of enzyme produced by 24 phage group II isolates.
View Article and Find Full Text PDFTo determine whether the infection-preventing capability of the neutrophil-activating agent poly-(1-6)-beta-D-glucopyranosyl-(1-3)-beta-D-glucopyranose glucan (PGG-glucan) can be enhanced with antibiotic prophylaxis, we administered PGG-glucan and cefazolin, alone and in combination, to guinea pigs inoculated with isolates of staphylococci. Guinea pigs receiving both PGG-glucan and cefazolin had 50% infective doses that were 8- to 20-fold higher than those obtained with cefazolin alone and 100- to 200-fold higher than those obtained with PGG-glucan alone. PGG-glucan and cefazolin are synergistic in their ability to prevent staphylococcal wound infection.
View Article and Find Full Text PDFAntimicrob Agents Chemother
June 1998
New antibiotic regimens are needed for the treatment of multidrug-resistant tuberculosis. Mycobacterium tuberculosis has a thick peptidoglycan layer, and the penicillin-binding proteins involved in its biosynthesis are inhibited by clinically relevant concentrations of beta-lactam antibiotics. beta-Lactamase production appears to be the major mechanism by which M.
View Article and Find Full Text PDFThe judicious use of perioperative antibiotic prophylaxis reduces the infectious complications of surgery. However, increased bacterial resistance within hospitals may make antibiotic prophylaxis less effective in the future and alternative strategies are needed. New immunomodulatory agents might prevent wound infections by stimulation of the host immune system.
View Article and Find Full Text PDF