Publications

Inflammatory bowel diseases encompass gastrointestinal illnesses typified by chronic inflammation, loss of epithelial integrity and gastrointestinal microbiota dysbiosis. In an effort to counteract these characteristic perturbations, we used stem cells and/or a probiotic therapy in a murine model of Dextran Sodium Sulfate induced colitis to examine both their efficacy in ameliorating disease and impact on niche-specific microbial communities of the lower GI tract. Colitis was induced in C57BL/6 mice by administering 3% DSS in drinking water for 10 days prior to administering one of three treatment plans: daily probiotic (VSL#3) supplementation for 3 days, a single tail vein injection of 1x10 (6) murine mesenchymal stem cells, or both. Ileal, cecal and colonic sections were collected for microbiota and histological analyses. Microbiota profiling revealed distinct bacterial community compositions in the ileum, cecum and colon of control untreated animals, all of which were predicted in silico to be enriched for a number of discrete KEGG pathways, indicating compositional and functional niche specificity in healthy animals. DSS-treatment perturbed community composition in all three niches with ileal communities exhibiting the greatest change relative to control animals. Each treatment group exhibited treatment-specific alterations in microbiota composition in the lower GI tract, though disease scores were only improved in VSL#3-treated animals. The ileal microbiota were most profoundly altered in composition in this group of animals and characterized by significant Enterobacteriaceae enrichment compared with colitic mice (P<0.05).

The production of β-lactamase is the most common mechanism of resistance to β-lactam antibiotics among gram-negative bacteria. Extended-spectrum β-lactamases (ESBLs) are capable of hydrolyzing most penicillins, extended-spectrum cephalosporins, and aztreonam, but their activity is suppressed in the presence of a β-lactamase inhibitor. Serious infections with ESBL-producing isolates are associated with high rates of mortality, making early detection and adequate medical management essential to ensure optimal patient outcomes. Much controversy has centered on the recommendations for testing and reporting of antibiotic susceptibility of potential ESBL-producing organisms. The latest version of the Clinical Laboratory Standards Institute (CLSI) susceptibility reporting guidelines, published in 2010, no longer advocates for phenotypic testing of ESBL-producing isolates. From newer studies demonstrating a correlation between organism minimum inhibitory concentration (MIC) and clinical outcome, along with pharmacokinetic/pharmacodynamic (PK/PD) modeling demonstrating the importance of the MIC to achieving therapeutic targets, the CLSI has assigned lower susceptibility breakpoints for aztreonam and most cephalosporins. The new guidelines recommend using the lower MIC breakpoints to direct antibiotic selection. This article reviews the microbiology and epidemiology of ESBLs, the recent change in CLSI susceptibility reporting guidelines for ESBLs, and the clinical and PK/PD data supporting the relationship between in vitro susceptibility and clinical outcome. Finally, considerations for antimicrobial selection when treating patients with infections caused by ESBL-producing organisms from various sources are discussed.

RATIONALE

HIV seropositivity has long been considered a contraindication to lung transplantation, primarily because of the potential risks of added immunosuppression. In the past decade, however, experience with kidney and liver transplantation in the setting of HIV infection, with achievement of satisfactory outcomes, has grown considerably. This promising development has created a need to reconsider this contraindication to lung transplantation.

OBJECTIVES

There is presently limited evidence upon which to base medical decision-making regarding lung transplantation in individuals with HIV infection. In our present study, we wished to extend the existing literature by reporting the outcomes of three individuals with HIV infection who underwent lung transplantation at two centers.

METHODS

We compiled data for a case series of three HIV-infected subjects undergoing lung transplantation at two centers.

MEASUREMENTS AND MAIN RESULTS

We reviewed medical records to investigate the effects of lung transplantation on the course of HIV infection, the development of HIV-related opportunistic infections or malignancies, the occurrence of lung transplant and HIV drug interactions, and the extent of acute rejection. Subject 1, who underwent transplantation for HIV-associated pulmonary arterial hypertension, experienced recalcitrant acute rejection requiring a lymphocyte-depleting agent with subsequent rapid development of bronchiolitis obliterans syndrome. Subjects 2 and 3, who underwent transplantation for idiopathic pulmonary fibrosis, experienced mild acute rejection but remain free from chronic rejection at 4 and 2 years after transplant, respectively.

CONCLUSIONS

Lung transplantation may be feasible for carefully selected patients in the setting of controlled HIV infection. On the basis of our experience with three patients, we caution that acute graft rejection may be more common in such patients.

BACKGROUND

Exposure to secondhand tobacco smoke (SHS) can be a risk factor for chronic obstructive pulmonary disease (COPD), but its role among relatively heavy smokers with potential co-exposure to workplace vapors, gas, dust, and fumes (VGDF) has not been studied.

METHODS

To estimate the contribution of SHS exposure to COPD risk, taking into account smoking effects and work-related exposures to VGDF, we quantified SHS based on survey responses for 1400 ever-employed subjects enrolled in the COPDGene study, all current or former smokers with or without COPD. Occupational exposures to VGDF were quantified based on a job exposure matrix. The associations between SHS and COPD were tested in multivariate logistic regression analyses adjusted for age, sex, VGDF exposure, and cumulative smoking.

RESULTS AND DISCUSSION

Exposures to SHS at work and at home during adulthood were associated with increased COPD risk: odds ratio (OR) = 1.12 (95% confidence interval [CI]: 1.02-1.23; p = 0.01) and OR = 1.09 (95%CI: 1.00-1.18; p = 0.04) per 10 years of exposure adjusted for smoking and other covariates, respectively. In addition, subjects with employment histories likely to entail exposure to VGDF were more likely to have COPD: OR = 1.52 (95%CI: 1.16-1.98; p < 0.01) (adjusted for other covariates). While adult home SHS COPD risk was attenuated among the heaviest smokers within the cohort, workplace SHS and job VGDF risks persisted in that stratum.

CONCLUSION

Among smokers all with at least 10 pack-years, adult home and work SHS exposures and occupational VGDF exposure are all associated with COPD.

OBJECTIVE

To provide further validation of the Brief Index of Lupus Damage (BILD), assessing its sensitivity to change in disease status and ability to predict mortality risk.

METHODS

Data were from the University of California, San Francisco Lupus Outcomes Study (n = 958), in which the BILD was administered twice, approximately 5 years apart. We examined disease activity and health care utilization among participants who completed the BILD twice (n = 745). We identified increases in disease activity and utilization that would suggest a disease flare between the 2 BILD administrations and compared their occurrence by BILD score increases (0, 1, 2, 3, >3). Deaths were ascertained when annual interviews were attempted. Kaplan-Meier life-table analysis compared mortality rates for 4 groups of initial BILD scores (0, 1, 2, ≥3), and differences were tested using a log rank test. Using Cox proportional hazards models, we estimated the risk of death associated with higher BILD scores.

RESULTS

BILD score increases were associated with spikes in disease activity (P = 0.05) and physician visits (P = 0.004) over baseline, and with hospitalizations (P < 0.001) during the intervening years. Of those with BILD score increases >3, 84% were hospitalized prior to the second BILD. During followup, there were 60 deaths (6.3%). BILD scores of 2 (hazard ratio [HR] 6.1, 95% confidence interval [95% CI] 1.3-30.0) and ≥3 (HR 10.8, 95% CI 2.5-46.2) were associated with higher risk of death.

CONCLUSION

This analysis provides evidence of the predictive validity of the BILD and its ability to detect change. While not intended to replace clinical evaluation of disease damage, the BILD appears to be a useful tool for research.

We conducted a longitudinal study of tobacco use among adults initiating antiretroviral therapy (ART) in Mbarara, Uganda where 11 % of men and 3 % of women use tobacco according to the 2011 Demographic and Health Survey. In a prospective cohort, self-reported tobacco use was assessed before starting ART and reassessed every 3-4 months. Plasma cotinine, a nicotine metabolite, was measured in a subset of adults pre-ART to verify self-report. Among 496 subjects, 50 (10 %) reported current tobacco use (20 % of men, 6 % of women). Most (53 %) adults with elevated cotinine levels (>15 ng/mL) reported no tobacco use. By 6 months after ART initiation, 33 % of tobacco users had quit (95 % CI 20-46 %). By 5 years, 64 % quit (95 % CI 47-77 %). Self-reported tobacco use among rural Ugandans starting ART was twice as common as among the local background population and use may be underreported. ART initiation could be an opportunity for tobacco cessation interventions.

PURPOSE OF REVIEW

It is now widely accepted that HIV-infected individuals remain at a higher risk for mortality and age-related morbidities than the general population, but several unresolved issues need to be addressed by the research community in the coming years to further improve the health of HIV-infected individuals in the modern treatment era.

RECENT FINDINGS

Although recent studies have helped to better define the contribution of HIV to life expectancy and morbidity in the modern antiretroviral therapy (ART) era, questions remain about the generalizability of these findings to a future HIV-infected population that is expected to be much older. Furthermore, although a consensus has emerged that the persistent inflammatory state contributes to morbidity and mortality in this setting, the relative contributions of this process, health-related behaviours, comorbidities and medication toxicities remain incompletely understood. Lastly, significant uncertainty remains over the root causes of the persistent inflammatory state, the specific immunologic pathways to target with interventions and the most appropriate biomarkers to use for surrogate outcomes in pilot trials of immune-based interventions.

SUMMARY

Each of these issues will be addressed in this review, highlighting recently published and presented studies that inform the discussion, and recommendations will be made for prioritizing the future research agenda.

New genomic sequencing technologies enable the high-speed analysis of multiple genes simultaneously, including all of those in a person's genome. Sequencing is a prominent example of a "big data" technology because of the massive amount of information it produces and its complexity, diversity, and timeliness. Our objective in this article is to provide a policy primer on sequencing and illustrate how it can affect health care system and policy issues. Toward this end, we developed an easily applied classification of sequencing based on inputs, methods, and outputs. We used it to examine the implications of sequencing for three health care system and policy issues: making care more patient-centered, developing coverage and reimbursement policies, and assessing economic value. We conclude that sequencing has great promise but that policy challenges include how to optimize patient engagement as well as privacy, develop coverage policies that distinguish research from clinical uses and account for bioinformatics costs, and determine the economic value of sequencing through complex economic models that take into account multiple findings and downstream costs.