Faculty Bibliography

Mammalian species have co-evolved with intestinal microbial communities that can shape development and adapt to environmental changes, including antibiotic perturbation or nutrient flux. In humans, especially children, microbiota disruption is common, yet the dynamic microbiome recovery from early-life antibiotics is still uncharacterized. Here we use a mouse model mimicking paediatric antibiotic use and find that therapeutic-dose pulsed antibiotic treatment (PAT) with a beta-lactam or macrolide alters both host and microbiota development. Early-life PAT accelerates total mass and bone growth, and causes progressive changes in gut microbiome diversity, population structure and metagenomic content, with microbiome effects dependent on the number of courses and class of antibiotic. Whereas control microbiota rapidly adapts to a change in diet, PAT slows the ecological progression, with delays lasting several months with previous macrolide exposure. This study identifies key markers of disturbance and recovery, which may help provide therapeutic targets for microbiota restoration following antibiotic treatment.

PURPOSE: Delivering the recommended care is an important quality measure that has been insufficiently studied in urology. Obstructive pyelonephritis is a suitable case study for this focus because many patients do not receive such care, although guidelines advocate decompression. We determined the influence of hospital factors, particularly familiarity with urolithiasis, on the likelihood of decompression in such patients. MATERIALS AND METHODS: We used the NIS from 2002 to 2011 to retrospectively identify patients admitted to community hospitals with severe infection and ureteral calculi. Hospital familiarity with nephrolithiasis was estimated by calculating hospital stone volume (divided into quartiles) and hospital treatment intensity (the decompression rate in patients with ureteral calculi and no infection). After calculating national estimates we performed logistic regression to determine the association between the receipt of decompression and hospital stone volume, controlling for treatment intensity and other covariates thought to be associated with receiving recommended care. RESULTS: Of an estimated 107,848 patients with obstructive pyelonephritis 27.4% failed to undergo decompression. Discrepancies were greatest between hospitals with the highest and lowest stone volumes (76% vs 25%, OR 2.77, 95% CI 1.94-3.96, p <0.01) as well as high and low treatment intensity (78% vs 37%, p <0.01). CONCLUSIONS: High hospital stone volume and treatment intensity were associated with an increased likelihood of receiving decompression. Such findings might be useful to identify hospitals and regions where access to quality urological care should be augmented.

BACKGROUND: The surgical robot has been widely adopted in the United States in spite of its high cost and controversy surrounding its benefit. Some have suggested that a "medical arms race" influences technology adoption. We wanted to determine whether a hospital would acquire a surgical robot if its nearest neighboring hospital already owned one. METHODS: We identified 554 hospitals performing radical prostatectomy from the Healthcare Cost and Utilization Project Statewide Inpatient Databases for seven states. We used publicly available data from the website of the surgical robot's sole manufacturer (Intuitive Surgical, Sunnyvale, CA) combined with data collected from the hospitals to ascertain the timing of robot acquisition during year 2001 to 2008. One hundred thirty four hospitals (24%) had acquired a surgical robot by the end of 2008. We geocoded the address of each hospital and determined a hospital's likelihood to acquire a surgical robot based on whether its nearest neighbor owned a surgical robot. We developed a Markov chain method to model the acquisition process spatially and temporally and quantified the "neighborhood effect" on the acquisition of the surgical robot while adjusting simultaneously for known confounders. RESULTS: After adjusting for hospital teaching status, surgical volume, urban status and number of hospital beds, the Markov chain analysis demonstrated that a hospital whose nearest neighbor had acquired a surgical robot had a higher likelihood itself acquiring a surgical robot. (OR=1.71, 95% CI: 1.07-2.72, p=0.02). CONCLUSION: There is a significant spatial and temporal association for hospitals acquiring surgical robots during the study period. Hospitals were more likely to acquire a surgical robot during the robot's early adoption phase if their nearest neighbor had already done so.

BACKGROUND: Case managers are employed in medical homes to coordinate care for clinically complex patients. OBJECTIVE: To measure the association of patient perceptions of case manager performance with overall satisfaction and subsequent health care utilization. DESIGN: Retrospective cohort study. SETTING: Integrated health system in Pennsylvania. PATIENTS: Members of the health system-owned health plan who 1) received primary care in the health system's clinics, 2) were exposed to clinic-embedded case managers, and 3) completed a survey of satisfaction with care. MEASUREMENTS: Survey assessment of case manager performance and overall satisfaction with care and claims-based assessment of case manager performance and subsequent hospitalizations or emergency department visits. Survey measures were dichotomized into very good versus less than very good. RESULTS: A total of 1755 patients (44%) completed the survey and 1415 met study criteria. Survey respondents who reported very good ratings of case manager performance across all items had a higher probability of reporting very good overall satisfaction with care (92.2% vs. 62.5%; P < 0.001) and had a lower incidence of subsequent emergency department visits (incidence rate ratio, 0.79 [95% CI, 0.64 to 0.98]; P = 0.029) but not hospitalizations (incidence rate ratio, 0.92 [CI, 0.75 to 1.11]; P = 0.37) up to 2 years after the survey compared with survey respondents who reported less-than-very good case manager performance on 1 or more questions on the survey. LIMITATIONS: Satisfaction data demonstrated substantial ceiling effects. Survey nonresponse may have introduced bias in the results. CONCLUSION: Patients' favorable perceptions of case managers are associated with higher overall satisfaction with care and may lower risk for future acute care use. PRIMARY FUNDING SOURCE: Robert Wood Johnson Foundation and the U.S. Department of Veterans Affairs.

Acquisition of the intestinal microbiota begins at birth, and a stable microbial community develops from a succession of key organisms. Disruption of the microbiota during maturation by low-dose antibiotic exposure can alter host metabolism and adiposity. We now show that low-dose penicillin (LDP), delivered from birth, induces metabolic alterations and affects ileal expression of genes involved in immunity. LDP that is limited to early life transiently perturbs the microbiota, which is sufficient to induce sustained effects on body composition, indicating that microbiota interactions in infancy may be critical determinants of long-term host metabolic effects. In addition, LDP enhances the effect of high-fat diet induced obesity. The growth promotion phenotype is transferrable to germ-free hosts by LDP-selected microbiota, showing that the altered microbiota, not antibiotics per se, play a causal role. These studies characterize important variables in early-life microbe-host metabolic interaction and identify several taxa consistently linked with metabolic alterations. PAPERCLIP:

Broad-spectrum antibiotics are frequently prescribed for children. The gut microbiota have functional roles in the development and differentiation of the host immune system. Early-life antibiotic use may have dynamic effects on the host microbiota, promoting long-term immunologic dysregulation and subsequent allergic and autoimmune pathology. Using a model of early-life antibiotic use, we hypothesize that early-life pulsed antibiotic treatment (PAT) -induced perturbation of the intestinal microbiota leads to alterations in tissue-specific and systemic T-cell populations. To test this hypothesis, we characterized splenic and ileal T-cell populations in control and PAT-treated C57BL/6 mice. Flow cytometric analysis demonstrated that early-life PAT significantly (p<0.05) decreased the frequency of splenic CD4+ and CD8+ T-cells and ileal CD4+ IL-17A+ Th17 populations. In contrast, ileal CD4+ Tbet+ (Th1) T cells and CD4+ Foxp3+ regulatory T-cell populations were significantly increased in PAT-treated mice. Alterations in immune cell populations were associated with microbial compositional changes, including significantly higher relative abundance of Enterobacteriaceae and Akkermansia muciniphila in PAT-treated mice. These results provide evidence that early-life perturbation of the intestinal microbiota by PAT modulates systemic and mucosal T-cell populations, phenotypes that may persist after microbial recovery, promoting life-long consequences to host immunity

In mammals, changes in the metabolic state, including obesity, fasting, cold challenge and high fat diets activate complex immune responses. In many strains of rodents, high fat diets induce a rapid systemic inflammatory response and lead to obesity. Little is known about the molecular signals required for high fat diet (HFD)-induced phenotypes. Here we studied the function of the receptor for advanced glycation products (RAGE) in the development of phenotypes associated with high fat feeding in mice. RAGE is highly expressed on immune cells, including macrophages. High fat feeding induced expression of RAGE ligand HMGB1 and carboxy methyl lysine (CML)-advanced glycation endproducts (AGE) epitopes in liver and adipose tissue. Genetic deficiency of RAGE prevented the effects of HFD on energy expenditure, weight gain, adipose tissue inflammation, and insulin resistance. RAGE deficiency had no effect on genetic forms of obesity caused by impaired melanocortin signaling. Hematopoietic deficiency of RAGE or treatment with soluble RAGE partially protected against peripheral HFD-induced inflammation and weight gain. These data argue that high fat feeding induces peripheral inflammation and weight gain in a RAGE-dependent manner, providing a foothold in the pathways that regulate diet-induced obesity and offering the potential for therapeutic intervention.

BACKGROUND: The increased risk of gastrointestinal (GI) cancers after Hodgkin's lymphoma (HL) is well established. However, no large population-based study has described the actuarial survival after subsequent GI cancers in HL survivors (HL-GI). PATIENTS AND METHODS: For 209 patients with HL-GI cancers (105 colon, 35 stomach, 30 pancreas, 21 rectum, and 18 esophagus) and 484 165 patients with first primary GI cancers (GI-1), actuarial survival was compared, accounting for age, gender, race, GI cancer stage, radiation for HL, and other variables. RESULTS: Though survival of HL patients who developed localized stage colon cancer was similar to that of the GI-1 group, overall survival (OS) of HL patients with regional or distant stage colon cancer was reduced [hazard ratio, (HR)=1.46, P=0.01]. The HL survivors with regional or distant stage colon cancer in the transverse segment had an especially high risk of mortality (HR: 2.7, P=0.001 for OS). For localized stomach cancer, OS was inferior among HL survivors (HR=3.46, P=0.006). CONCLUSIONS: The HL patients who develop GI cancer experience significantly reduced survival compared with patients with a first primary GI cancer. Further research is needed to explain the inferior survival of HL patients and to define selection criteria for cancer screening in HL survivors.

Background. Diabetic foot infections are a leading cause of lower extremity amputations. Our study examines the microbiota of diabetic skin prior to ulcer development or infection. Methods. In a case-control study, outpatient males were recruited at a veterans hospital. Subjects were swabbed at 4 cutaneous sites, 1 on the forearm and 3 on the foot. Quantitative polymerase chain reaction (qPCR) with primers and probes specific for bacteria, Staphylococcus species, Staphylococcus aureus, and fungi were performed on all samples. High-throughput 16S ribosomal RNA (rRNA) sequencing was performed on samples from the forearm and the plantar aspect of the foot. Results. qPCR analysis of swab specimens from 30 diabetic subjects and 30 control subjects showed no differences in total numbers of bacteria or fungi at any sampled site. Increased log concentrations of Staphylococcus aureus, quantified by the number of nuc gene copies, were present in diabetic men on the plantar aspect of the foot. High-throughput 16S rRNA sequencing found that, on the foot, the microbiota in controls (n = 24) was dominated by Staphylococcus species, whereas the microbiota in diabetics (n = 23) was more diverse at the genus level. The forearm microbiota had similar diversity in diabetic and control groups. Conclusions. The feet of diabetic men had decreased populations of Staphylococcus species, increased populations of S. aureus, and increased bacterial diversity, compared with the feet of controls. These ecologic changes may affect the risk for wound infections.