Factors associated with anxiety during the first two years of the COVID-19 pandemic in the United States: An analysis of the COVID-19 Citizen Science study

COVID-19 increased the prevalence of clinically significant anxiety in the United States. To investigate contributing factors we analyzed anxiety, reported online via monthly Generalized Anxiety Disorders-7 (GAD-7) surveys between April 2020 and May 2022, in association with self-reported worry about the health effects of COVID-19, economic difficulty, personal COVID-19 experience, and subjective social status. 333,292 anxiety surveys from 50,172 participants (82% non-Hispanic white; 73% female; median age 55, IQR 42-66) showed high levels of anxiety, especially early in the pandemic. Anxiety scores showed strong independent associations with worry about the health effects of COVID-19 for oneself or family members (GAD-7 score +3.28 for highest vs. lowest category; 95% confidence interval: 3.24, 3.33; p<0.0001 for trend) and with difficulty paying for basic living expenses (+2.06; 1.97, 2.15, p<0.0001) in multivariable regression models after adjusting for demographic characteristics, COVID-19 case rates and death rates, and personal COVID-19 experience. High levels of COVID-19 health worry and economic stress were each more common among participants reporting lower subjective social status, and median anxiety scores for those experiencing both were in the range considered indicative of moderate to severe clinical anxiety disorders. In summary, health worry and economic difficulty both contributed to high rates of anxiety during the first two years of the COVID-19 pandemic in the US, especially in disadvantaged socioeconomic groups. Programs to address both health concerns and economic insecurity in vulnerable populations could help mitigate pandemic impacts on anxiety and mental health.

External validity in distributed data networks

PURPOSE

While much has been written about how distributed networks address internal validity, external validity is rarely discussed. We aimed to define key terms related to external validity, discuss how they relate to distributed networks, and identify how three networks (the US Food and Drug Administration's Sentinel System, the Canadian Network for Observational Drug Effect Studies [CNODES], and the National Patient Centered Clinical Research Network [PCORnet]) deal with external validity.

METHODS

We define external validity, target populations, target validity, generalizability, and transportability and describe how each relates to distributed networks. We then describe Sentinel, CNODES, and PCORnet and how each approaches these concepts, including a sample case study.

RESULTS

Each network approaches external validity differently. As its target population is US citizens and it includes only US data, Sentinel primarily worries about lack of external validity by not including some segments of the population. The fact that CNODES includes Canadian, United States, and United Kingdom data forces them to seriously consider whether the United States and United Kingdom data will be transportable to Canadian citizens when they meta-analyze database-specific estimates. PCORnet, with its focus on study-specific cohorts and pragmatic trials, conducts more case-by-case explorations of external validity for each new analytic data set it generates.

CONCLUSIONS

There is no one-size-fits-all approach to external validity within distributed networks. With these networks and comparisons between their findings becoming a key part of pharmacoepidemiology, there is a need to adapt tools for improving external validity to the distributed network setting.

Evaluation of the microbiota-sparing properties of the anti-staphylococcal antibiotic afabicin

BACKGROUND

Antibiotic use is associated with collateral damage to the healthy microbiota. Afabicin is a first-in-class prodrug inhibitor of the FabI enzyme that, when converted to the pharmacologically active agent afabicin desphosphono, demonstrates a staphylococcal-specific spectrum of activity. An expected benefit of highly targeted antibiotics such as afabicin is microbiome preservation.

OBJECTIVES

To compare the effects of oral treatment with afabicin and standard-of-care antibiotics upon the murine gut microbiota, and to assess the effects of oral afabicin treatment on the human gut microbiota.

METHODS

Gut microbiota effects of a 10 day oral course of afabicin treatment were monitored in mice and compared with clindamycin, linezolid and moxifloxacin at human-equivalent dose levels using 16S rDNA sequencing. Further, the gut microbiota of healthy volunteers was longitudinally assessed across 20 days of oral treatment with afabicin 240 mg twice daily.

RESULTS

Afabicin treatment did not significantly alter gut microbiota diversity (Shannon H index) or richness (rarefied Chao1) in mice. Only limited changes to taxonomic abundances were observed in afabicin-treated animals. In contrast, clindamycin, linezolid and moxifloxacin each caused extensive dysbiosis in the murine model. In humans, afabicin treatment was not associated with alterations in Shannon H or rarefied Chao1 indices, nor relative taxonomic abundances, supporting the findings from the animal model.

CONCLUSIONS

Oral treatment with afabicin is associated with preservation of the gut microbiota in mice and healthy subjects.

Disruption in Blood Pressure Control With the COVID-19 Pandemic: The PCORnet Blood Pressure Control Laboratory

OBJECTIVE

To explore trends in blood pressure (BP) control before and during the COVID-19 pandemic.

PATIENTS AND METHODS

Health systems participating in the National Patient-Centered Clinical Research Network (PCORnet) Blood Pressure Control Laboratory Surveillance System responded to data queries, producing 9 BP control metrics. Averages of the BP control metrics (weighted by numbers of observations in each health system) were calculated and compared between two 1-year measurement periods (January 1, 2019, through December 31, 2019, and January 1, 2020, through December 31, 2020).

RESULTS

Among 1,770,547 hypertensive persons in 2019, BP control to <140/<90 mm Hg varied across 24 health systems (range, 46%-74%). Reduced BP control occurred in most health systems with onset of the COVID-19 pandemic; the weighted average BP control was 60.5% in 2019 and 53.3% in 2020. Reductions were also evident for BP control to <130/<80 mm Hg (29.9% in 2019 and 25.4% in 2020) and improvement in BP (reduction of 10 mm Hg in systolic BP or achievement of systolic BP <140 mm Hg; 29.7% in 2019 and 23.8% in 2020). Two BP control process metrics exhibited pandemic-associated disruption: repeat visit in 4 weeks after a visit with uncontrolled hypertension (36.7% in 2019 and 31.7% in 2020) and prescription of fixed-dose combination medications among those with 2 or more drug classes (24.6% in 2019 and 21.5% in 2020).

CONCLUSION

BP control decreased substantially during the COVID-19 pandemic, with a corresponding reduction in follow-up health care visits among persons with uncontrolled hypertension. It is unclear whether the observed decline in BP control during the pandemic will contribute to future cardiovascular events.

Seasonal variation in blood pressure control across US health systems

OBJECTIVE

We aimed to characterize seasonal variation in US population-based blood pressure (BP) control and BP-related metrics and evaluate the association between outdoor temperature and BP control variation.

METHODS

We queried electronic health records (EHRs) from 26 health systems, representing 21 states, to summarize BP metrics by quarters of 12-month periods from January 2017 to March 2020. Patients with at least one ambulatory visit during the measurement period and a hypertension diagnosis during the first 6 months or prior to the measurement period were included. Changes in BP control, BP improvement, medication intensification, average SBP reduction after medication intensification across quarters and association with outdoor temperature were analyzed using weighted generalized linear models with repeated measures.

RESULTS

Among 1 818 041 people with hypertension, the majority were more than 65 years of age (52.2%), female (52.1%), white non-Hispanic (69.8%) and had stage 1/2 hypertension (64.8%). Overall, BP control and process metrics were highest in quarters 2 and 3, and lowest in quarters 1 and 4. Quarter 2 had the highest percentage of improved BP (31.95 ± 0.90%) and average SBP reduction after medication intensification (16 ± 0.23 mmHg). Quarter 3 had the highest percentage of BP controlled (62.25 ± 2.55%) and lowest with medication intensification (9.73 ± 0.60%). Results were largely consistent in adjusted models. Average temperature was associated with BP control metrics in unadjusted models, but associations were attenuated following adjustment.

CONCLUSION

In this large, national, EHR-based study, BP control and BP-related process metrics improved during spring/summer months, but outdoor temperature was not associated with performance following adjustment for potential confounders.

Risk Factors and Predictive Modeling for Post-Acute Sequelae of SARS-CoV-2 Infection: Findings from EHR Cohorts of the RECOVER Initiative

Background

Patients who were SARS-CoV-2 infected could suffer from newly incidental conditions in their post-acute infection period. These conditions, denoted as the post-acute sequelae of SARS-CoV-2 infection (PASC), are highly heterogeneous and involve a diverse set of organ systems. Limited studies have investigated the predictability of these conditions and their associated risk factors.

Method

In this retrospective cohort study, we investigated two large-scale PCORnet clinical research networks, INSIGHT and OneFlorida+, including 11 million patients in the New York City area and 16.8 million patients from Florida, to develop machine learning prediction models for those who are at risk for newly incident PASC and to identify factors associated with newly incident PASC conditions. Adult patients aged 20 with SARS-CoV-2 infection and without recorded infection between March 1st, 2020, and November 30th, 2021, were used for identifying associated factors with incident PASC after removing background associations. The predictive models were developed on infected adults.

Results

We find several incident PASC, e.g., malnutrition, COPD, dementia, and acute kidney failure, were associated with severe acute SARS-CoV-2 infection, defined by hospitalization and ICU stay. Older age and extremes of weight were also associated with these incident conditions. These conditions were better predicted (C-index >0.8). Moderately predictable conditions included diabetes and thromboembolic disease (C-index 0.7-0.8). These were associated with a wider variety of baseline conditions. Less predictable conditions included fatigue, anxiety, sleep disorders, and depression (C-index around 0.6).

Conclusions

This observational study suggests that a set of likely risk factors for different PASC conditions were identifiable from EHRs, predictability of different PASC conditions was heterogeneous, and using machine learning-based predictive models might help in identifying patients who were at risk of developing incident PASC.

Improvement in Blood Pressure Control in Safety Net Clinics Receiving 2 Versions of a Scalable Quality Improvement Intervention: BP MAP A Pragmatic Cluster Randomized Trial

Background Uncontrolled blood pressure (BP) remains a leading cause of death in the United States. The American Medical Association developed a quality improvement program to improve BP control, but it is unclear how to efficiently implement this program at scale across multiple health systems. Methods and Results We conducted BP MAP (Blood Pressure Measure Accurately, Act Rapidly, and Partner With Patients), a comparative effectiveness trial with clinic-level randomization to compare 2 scalable versions of the quality improvement program: Full Support (with support from quality improvement expert) and Self-Guided (using only online materials). Outcomes were clinic-level BP control (<140/90 mm Hg) and other BP-related process metrics calculated using electronic health record data. Difference-in-differences were used to compare changes in outcomes from baseline to 6 months, between intervention arms, and to a nonrandomized Usual Care arm composed of 18 health systems. A total of 24 safety-net clinics in 9 different health systems underwent randomization and then simultaneous implementation. BP control increased from 56.7% to 59.1% in the Full Support arm, and 62.0% to 63.1% in the Self-Guided arm, whereas BP control dropped slightly from 61.3% to 60.9% in the Usual Care arm. The between-group differences-in-differences were not statistically significant (Full Support versus Self-Guided=+1.2% [95% CI, -3.2% to 5.6%], P=0.59; Full Support versus Usual Care=+3.2% [-0.5% to 6.9%], P=0.09; Self-Guided versus Usual Care=+2.0% [-0.4% to 4.5%], P=0.10). Conclusions In this randomized trial, 2 methods of implementing a quality improvement intervention in 24 safety net clinics led to modest improvements in BP control that were not statistically significant. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03818659.

Unreported SARS-CoV-2 Home Testing and Test Positivity

This cohort study examines time trends in officially reported SARS-CoV-2 case counts and unreported home test positivity.

Microbiota-induced regulatory T cells associate with FUT2-dependent susceptibility to rotavirus gastroenteritis

The FUT2 α1,2fucosyltransferase contributes to the synthesis of fucosylated glycans used as attachment factors by several pathogens, including noroviruses and rotaviruses, that can induce life-threatening gastroenteritis in young children. FUT2 genetic polymorphisms impairing fucosylation are strongly associated with resistance to dominant strains of both noroviruses and rotaviruses. Interestingly, the wild-type allele associated with viral gastroenteritis susceptibility inversely appears to be protective against several inflammatory or autoimmune diseases for yet unclear reasons, although a FUT2 influence on microbiota composition has been observed. Here, we studied a cohort of young healthy adults and showed that the wild-type FUT2 allele was associated with the presence of anti-RVA antibodies, either neutralizing antibodies or serum IgA, confirming its association with the risk of RVA gastroenteritis. Strikingly, it was also associated with the frequency of gut microbiota-induced regulatory T cells (Tregs), so-called DP8α Tregs, albeit only in individuals who had anti-RVA neutralizing antibodies or high titers of anti-RVA IgAs. DP8α Tregs specifically recognize the human symbiont Faecalibacterium prausnitzii, which strongly supports their induction by this anti-inflammatory bacterium. The proportion of F. prausnitzii in feces was also associated with the FUT2 wild-type allele. These observations link the FUT2 genotype with the risk of RVA gastroenteritis, the microbiota and microbiota-induced DP8α Treg cells, suggesting that the anti-RVA immune response might involve an induction/expansion of these T lymphocytes later providing a balanced immunological state that confers protection against inflammatory diseases.

Assessing the impact of privacy-preserving record linkage on record overlap and patient demographic and clinical characteristics in PCORnet®, the National Patient-Centered Clinical Research Network

OBJECTIVE

This article describes the implementation of a privacy-preserving record linkage (PPRL) solution across PCORnet®, the National Patient-Centered Clinical Research Network.

MATERIAL AND METHODS

Using a PPRL solution from Datavant, we quantified the degree of patient overlap across the network and report a de-duplicated analysis of the demographic and clinical characteristics of the PCORnet population.

RESULTS

There were ∼170M patient records across the responding Network Partners, with ∼138M (81%) of those corresponding to a unique patient. 82.1% of patients were found in a single partner and 14.7% were in 2. The percentage overlap between Partners ranged between 0% and 80% with a median of 0%. Linking patients' electronic health records with claims increased disease prevalence in every clinical characteristic, ranging between 63% and 173%.

DISCUSSION

The overlap between Partners was variable and depended on timeframe. However, patient data linkage changed the prevalence profile of the PCORnet patient population.

CONCLUSIONS

This project was one of the largest linkage efforts of its kind and demonstrates the potential value of record linkage. Linkage between Partners may be most useful in cases where there is geographic proximity between Partners, an expectation that potential linkage Partners will be able to fill gaps in data, or a longer study timeframe.

Establishing a framework for privacy-preserving record linkage among electronic health record and administrative claims databases within PCORnet®, the National Patient-Centered Clinical Research Network

OBJECTIVE

The aim of this study was to determine whether a secure, privacy-preserving record linkage (PPRL) methodology can be implemented in a scalable manner for use in a large national clinical research network.

RESULTS

We established the governance and technical capacity to support the use of PPRL across the National Patient-Centered Clinical Research Network (PCORnet^®). As a pilot, four sites used the Datavant software to transform patient personally identifiable information (PII) into de-identified tokens. We queried the sites for patients with a clinical encounter in 2018 or 2019 and matched their tokens to determine whether overlap existed. We described patient overlap among the sites and generated a "deduplicated" table of patient demographic characteristics. Overlapping patients were found in 3 of the 6 site-pairs. Following deduplication, the total patient count was 3,108,515 (0.11% reduction), with the largest reduction in count for patients with an "Other/Missing" value for Sex; from 198 to 163 (17.6% reduction). The PPRL solution successfully links patients across data sources using distributed queries without directly accessing patient PII. The overlap queries and analysis performed in this pilot is being replicated across the full network to provide additional insight into patient linkages among a distributed research network.

Effectiveness of Standard vs Enhanced Self-measurement of Blood Pressure Paired With a Connected Smartphone Application: A Randomized Clinical Trial

Importance

Self-measured blood pressure (SMBP) with commercially available connected smartphone applications may help patients effectively use SMBP measurements.

Objective

To determine if enhanced SMBP paired with a connected smartphone application was superior to standard SMBP for blood pressure (BP) reduction or patient satisfaction.

Design, Setting, and Participants

This randomized clinical trial was conducted among 23 health systems participating in PCORnet, the National Patient-Centered Clinical Research Network, and included patients who reported having uncontrolled BP at their last clinic visit, a desire to lower their BP, and a smartphone. Enrollment and randomization occurred from August 3, 2019, to December 31, 2020, which was followed by 6 months of follow-up for each patient. Analysis commenced shortly thereafter.

Interventions

Eligible participants were randomly assigned to enhanced SMBP using a device that paired with a connected smartphone application (enhanced) or a standard device (standard). Participants received their device in the mail, along with web-based educational materials and phone-based support as needed. No clinician engagement was undertaken, and the study provided no special mechanisms for delivering measurements to clinicians for use in BP management.

Main Outcomes and Measures

Reduction in systolic BP, defined as the difference between clinic BP at baseline and the most recent clinic BP extracted from electronic health records at 6 months.

Results

Enrolled participants (1051 enhanced [50.0%] vs 1050 standard [50.0%]; 1191 women [56.7%]) were mostly middle-aged or older (mean [SD] age, 58 [13] years), nearly a third were Black or Hispanic (645 [31%]), and most were relatively comfortable using technology (mean [SD], 4.1 [1.1] of 5). The mean (SD) change in systolic BP from baseline to 6 months was -10.8 (18) mm Hg vs -10.6 (18) mm Hg (enhanced vs standard: adjusted difference, -0.19 mm Hg; 95% CI, -1.83 to 1.44; P = .81). Secondary outcomes were mostly null, except for documented attainment of BP control to lower than 140/<90 mm Hg, which occurred in 32% enhanced vs 29% standard groups (odds ratio, 1.15; 95% CI, 1.01-1.34). Most participants were very likely to recommend their SMBP device to a friend (70% vs 69%).

Conclusions and Relevance

This randomized clinical trial found that enhanced SMBP paired with a smartphone application is not superior to standard SMBP for BP reduction or patient satisfaction.

Trial Registration

ClinicalTrials.gov Identifier: NCT03796689.

Dance of Dollars: State Funding Effects on Local Health Department Expenditures

OBJECTIVE

We examined changes in total local health department (LHD) expenditures in the state of Washington following introduction of a new state funding program to support core public health services and infrastructure.

METHODS

We used a pre/posttest design regression model to evaluate changes in LHD expenditures 1, 2, and 6 years into the new state program. To address potential endogeneity in the model, we repeated all 3 analyses using 2-stage least squares regression.

RESULTS

In the base case, overall spending among LHDs significantly increased with receipt of the new state funds in the first years of the program (2008 and 2009). However, those increases were not sustained over the longer term (2013). In subpopulation analyses, total LHD spending increased more among larger LHDs.

CONCLUSIONS

Between 2006 and 2013, new state investments in core public health functions increased Washington State LHD expenditures in the short term, but those increases did not persist over time. For public health financial modernization efforts to translate into public health infrastructure modernization successes, the way new investments are structured may be as important as the amount of funding added.

Tracking Blood Pressure Control Performance and Process Metrics in 25 US Health Systems: The PCORnet Blood Pressure Control Laboratory

Background The National Patient-Centered Clinical Research Network Blood Pressure Control Laboratory Surveillance System was established to identify opportunities for blood pressure (BP) control improvement and to provide a mechanism for tracking improvement longitudinally. Methods and Results We conducted a serial cross-sectional study with queries against standardized electronic health record data in the National Patient-Centered Clinical Research Network (PCORnet) common data model returned by 25 participating US health systems. Queries produced BP control metrics for adults with well-documented hypertension and a recent encounter at the health system for a series of 1-year measurement periods for each quarter of available data from January 2017 to March 2020. Aggregate weighted results are presented overall and by race and ethnicity. The most recent measurement period includes data from 1 737 995 patients, and 11 956 509 patient-years were included in the trend analysis. Overall, 15% were Black, 52% women, and 28% had diabetes. BP control (<140/90 mm Hg) was observed in 62% (range, 44%-74%) but varied by race and ethnicity, with the lowest BP control among Black patients at 57% (odds ratio, 0.79; 95% CI, 0.66-0.94). A new class of antihypertensive medication (medication intensification) was prescribed in just 12% (range, 0.6%-25%) of patient visits where BP was uncontrolled. However, when medication intensification occurred, there was a large decrease in systolic BP (≈15 mm Hg; range, 5-18 mm Hg). Conclusions Major opportunities exist for improving BP control and reducing disparities, especially through consistent medication intensification when BP is uncontrolled. These data demonstrate substantial room for improvement and opportunities to close health equity gaps.

Faecal Microbiota Composition Varies between Patients with Breast Cancer and Healthy Women: A Comparative Case-Control Study

The intestinal microbiota plays an essential role in many diseases, such as obesity, irritable bowel disease (IBD), and cancer. This study aimed to characterize the faecal microbiota from early-stage breast cancer (BC) patients and healthy controls. Faeces from newly diagnosed breast cancer patients, mainly for an invasive carcinoma of no specific type (HR⁺ and HER2⁻), before any therapeutic treatment and healthy controls were collected for metabarcoding analyses. We show that the Shannon index, used as an index of diversity, was statistically lower in the BC group compared to that of controls. This work highlights a reduction of microbial diversity, a relative enrichment in Firmicutes, as well as a depletion in Bacteroidetes in patients diagnosed with early BC compared to those of healthy women. A tendency towards a decreased relative abundance of Odoribacter sp., Butyricimonas sp., and Coprococcus sp. was observed. This preliminary study suggests that breast cancer patients may differ from healthy subjects in their intestinal bacterial composition.

Factors Associated With Access to and Timing of Coronavirus Testing Among US Adults After Onset of Febrile Illness

Importance

Active SARS-CoV-2 (coronavirus) transmission continues in the US. It is unclear whether better access to coronavirus testing and more consistent use of testing could substantially reduce transmission.

Objective

To describe coronavirus testing in persons with new onset of febrile illness and analyze whether there are changes over time and differences by race and ethnicity.

Design, Setting, and Participants

This cohort study used data from the COVID-19 Citizen Science Study, launched in March 2020, which recruited participants via press release, word-of-mouth, and partner organizations. Participants completed daily surveys about COVID-19 symptoms and weekly surveys about coronavirus testing. All adults (aged at least 18 years) with a smartphone were eligible to join. For this analysis, US participants with new onset of febrile illness from April 2020 to October 2020 were included. Data analysis was performed from November 2020 to March 2021.

Main Outcomes and Measures

Receipt of a coronavirus test result within 7 days of febrile illness onset.

Results

Of the 2679 participants included in this analysis, the mean (SD) age was 46.3 (13.4) years, 1983 were female (74%), 2017 were college educated (75%), and a total of 3865 distinct new febrile illness episodes were reported (300 episodes [7.8%] from Hispanic participants, 71 episodes [1.8%] from Black participants, and 3494 episodes [90.4%] from not Black, not Hispanic participants) between April 2 and October 23, 2020. In weekly surveys delivered during the 14 days after fever onset, 12% overall (753 participants) indicated receipt of a test result. Using serial survey responses and parametric time-to-event modeling, it was estimated that by 7 days after onset of febrile illness, a total of 20.5% (95% CI, 19.1%-22.0%) had received a test result. This proportion increased from 9.8% (95% CI, 7.5%-12.0%) early in the epidemic to 24.1% (95% CI, 21.5%-26.7%) at the end of July, but testing rates did not substantially improve since then, increasing to 25.9% (95% CI; 21.6%-30.3%) in late October at the start of the winter surge. Black participants reported receiving a test result about half as often as others (7% [7 of 103] of survey responses vs 12% [53 of 461] for Hispanic vs 13% [693 of 5516] for not Black, not Hispanic; P = .03). This association was not statistically significant in adjusted time-to-event models (hazard ratio = 0.59 vs not Black, not Hispanic participants; 95% CI, 0.26-1.34).

Conclusions and Relevance

Systematic underuse of coronavirus testing was observed in this cohort study through late October 2020, at the beginning of the winter COVID-19 surge, which may have contributed to preventable coronavirus transmission.

Impact of pemetrexed chemotherapy on the gut microbiota and intestinal inflammation of patient-lung-derived tumor xenograft (PDX) mouse models

Chemotherapy remains the gold standard for advanced cancer. Pemetrexed, a chemotherapeutic agent used in non-small cell lung cancer, can induce significant side effects in patients. Although microbiota’s role in the efficacy and/or toxicity of chemotherapy agents has been demonstrated, the impacts of pemetrexed on the gut microbiota and on gastrointestinal inflammation remain unknown. The objective of this study was to evaluate the impact of pemetrexed and the tumor graft on the gut microbiota composition in immunodeficient mice. The faecal microbiota composition was studied with metabarcoding before, 24-h and one week after treatment. The colon epithelial barrier integrity was evaluated by histological examination, intestinal permeability measurement, and selected cytokines quantification. The tumor graft induced some variations in the microbiota composition. Pemetrexed further increased the relative abundance of Enterobacteriaceae and 3 families from the Firmicutes phylum: Enterococcaceae, Lactobacillaceae and Streptococcaceae. Pemetrexed also significantly altered the epithelial barrier integrity, which was associated with early inflammation. This pilot study shows that the association of a lung tumor graft with pemetrexed causes an alteration in the microbiota composition. Such information increases our knowledge about the impact of chemotherapy on the microbiota, which could help to minimize side effects and improve therapeutic effectiveness in the future.

Viability of MCF7 Cells Exposed to Basolateral Secretion from CaCo2 Cells Pretreated with Fecal Waters from Breast Cancer Patients and Controls

Objectives

There is increasing evidence suggesting that microbiota may play a role in breast cancer disease and influence the disease severity. Several mechanisms may be involved in this relationship. Our hypothesis is that the role of microbiota in the disease may be at least partly related to its influence in gut lipid and lipoprotein metabolisms. This hypothesis was tested in an in vitro model combining MCF7 and Caco2 cells.

Methods

32 women newly diagnosed for breast cancer, before any treatment and 28 apparently healthy women provided their stools from which bacterial DNA was extracted and amplified by qPCR, targeting 16S rRNA sequences specific to bacterial groups. Fecal waters (FW) were also obtained from these stools. Intestinal Caco-2 cells grown on filter inserts were incubated apically with 10% FW for 24 h. Then, MCF-7 cells were incubated with the whole basolateral medium for 24 h. The viability of these cells was estimated by MTT test. In parallel, LXR, apolipoproteins AIV and E gene expression was estimated by RT QPCR in CaCo2 cells and short chain fatty acids (SCFA) were quantified in FW. A logistic regression model was used to establish the Odds ratios (OR) for the disease of MCF7 viability and CaCo2 gene expression. The relationship between % bacterial groups, CaCo2 gene expression, SCFA and viability was established by regression models.

Results

Patients and controls differed by the MCF7 viability (1.05 [1.01–1.10], p = 0.04) and a tendency towards a difference was observed for apo AIV gene expression (0.63 [0.39–1.01], p = 0.055), (OR [5th-95th]). Viability was positively correlated with % Bifidobacterium sp.  (21.18 ± 7.66, p = 0.008) and negatively correlated with valerate (−2.849 ± 1.048, p = 0.009), (ß±s.d.). These correlations were maintained in a multiple regression model.

Conclusions

Microbiota may interact with intestine cell lipid metabolism and therefore influence cancer disease through gut cell secretion or permeability.

Funding Sources

Ligue Contre le cancer and private funds from Integrated Center for Oncology.

The PCORnet Blood Pressure Control Laboratory: A Platform for Surveillance and Efficient Trials

BACKGROUND

Uncontrolled blood pressure (BP) is a leading preventable cause of death that remains common in the US population despite the availability of effective medications. New technology and program innovation has high potential to improve BP but may be expensive and burdensome for patients, clinicians, health systems, and payers and may not produce desired results or reduce existing disparities in BP control.

METHODS AND RESULTS

The PCORnet Blood Pressure Control Laboratory is a platform designed to enable national surveillance and facilitate quality improvement and comparative effectiveness research. The platform uses PCORnet, the National Patient-Centered Clinical Research Network, for engagement of health systems and collection of electronic health record data, and the Eureka Research Platform for eConsent and collection of patient-reported outcomes and mHealth data from wearable devices and smartphones. Three demonstration projects are underway: BP track will conduct national surveillance of BP control and related clinical processes by measuring theory-derived pragmatic BP control metrics using electronic health record data, with a focus on tracking disparities over time; BP MAP will conduct a cluster-randomized trial comparing effectiveness of 2 versions of a BP control quality improvement program; BP Home will conduct an individual patient-level randomized trial comparing effectiveness of smartphone-linked versus standard home BP monitoring. Thus far, BP Track has collected electronic health record data from over 826 000 eligible patients with hypertension who completed ≈3.1 million ambulatory visits. Preliminary results demonstrate substantial room for improvement in BP control (<140/90 mm Hg), which was 58% overall, and in the clinical processes relevant for BP control. For example, only 12% of patients with hypertension with a high BP measurement during an ambulatory visit received an order for a new antihypertensive medication.

CONCLUSIONS

The PCORnet Blood Pressure Control Laboratory is designed to be a reusable platform for efficient surveillance and comparative effectiveness research; results from demonstration projects are forthcoming.

Abstract P2050: The Pcornet Blood Pressure Control Laboratory

Background: New technology and healthcare delivery approaches may help improve blood pressure (BP) control. Randomized controlled trials (RCTs) can demonstrate effectiveness of these emerging approaches, both overall and especially within underserved populations, but RCTs are expensive. Our objective is to establish a national platform to support BP control surveillance and efficient RCTs.

Methods: The PCORnet BP Control Laboratory, designed and launched in partnership with the American Heart Association (AHA) and the American Medical Association (AMA), leverages electronic health record (EHR) systems throughout the US, the National Patient-Centered Outcomes Research Network (PCORnet), and the NIH-funded Eureka Research Platform, which enables direct-to-participant research including collection of patient-reported outcomes and mHealth data from wearable devices and smartphones. We will use these resources to 1) Conduct national surveillance through quarterly EHR data queries to calculate and track institution- and clinic-level BP control metrics across 23 PCORnet institutions, overall and within key subgroups, and support participation in the AHA/AMA’s Target:BP recognition program (BP Track); 2) Compare effectiveness of a Full Support versus Self-Guided version of the AMA’s Measure Accurately, Act Rapidly, and Partner with Patients (MAP) program at improving BP control in a cluster randomized trial of 24 safety net clinics (BP MAP); and 3) Compare effectiveness of Smartphone-linked versus standard home BP monitoring at reducing systolic BP in an individual-level, direct-to-participant RCT of 2000 patients with uncontrolled BP (BP Home).

Results: Preliminary BP Track queries demonstrate an overall BP control rate of 56%, lower control in Black patients (51%), substantial heterogeneity in clinic-level metrics (e.g., 33% vs. 64% BP control), and low rates of medication intensification (9% prescribed a new medication class when BP was high). BP Track will launch PCORnet-wide queries in June; BP MAP in May; and BP Home in August 2019.

Conclusions: Feasibility testing is underway to determine if the PCORnet BP Control Laboratory will be useful for investigators interested in conducting efficient RCTs of BP control interventions.

Abstract 662: Impact of chemotherapy on the intestinal microbiome and epithelial barrier in PDX models of lung cancer

Introduction In the field of lung cancer treatments, significant progresses have been realized during last decade, such as targeted therapies and immunotherapies. Nevertheless, chemotherapy remains the gold standard for cancer. Pemetrexed is a chemotherapeutic agent commonly used in advanced lung cancer. This drug has a broad-spectrum effect that can induce significant side effects in patients. However, the impact of pemetrexed on gut microbiota and gastrointestinal inflammation in PDX mice remains unknown, although the role of the microbiota in carcinogenesis and modulation of efficacy or toxicity of chemotherapy agents has been demonstrated. The aim of this new study was to explore the impact of pemetrexed on the gut microbiota and the integrity of intestinal epithelial barrier and inflammation markers of PDX models following treatment.

Methods Upon establishment of the PDX model, mice were treated with pemetrexed for 2 weeks. Stool specimens were collected at 3 time-points: before, after and one week after treatment. Gut microbiota composition was studied by 16S rRNA gene sequencing. The colon integrity of the epithelial barrier was evaluated by a histological examination, a permeability measurement and a selected cytokines expression. In parallel, body weight was recorded and tissues were sampled for assessment of toxicity and inflammation.

Results Pemetrexed induced a significant body weight loss after each treatment cycle reflecting toxicity as known in clinical results. We have found that pemetrexed and tumor induced several modifications on microbiota composition, and the more important perturbation was the significant increase of the relative abundance of Enterobacteriaceae. A significant alteration of epithelial barrier integrity associated with early inflammation and infiltration of leukocytes into mucosal tissues was observed following treatment. Moreover, we have shown that pemetrexed effect on the microbiota was reproducible on several models of lung PDX models of lung carcinoma, and that dysbiosis seem proportional to the effectiveness of chemotherapy.

Conclusion This work is a preliminary approach, that confirms the relationship between microbiota and chemotherapy. A better understanding of gut microbiota alterations induced by chemotherapy could help reduce side effects. It is essential to expand our knowledge about the chemotherapy impact on microbiota in order to minimize the side effects, avoid infection complications, and improve therapy efficiency.

Citation Format: Cindy Pensec, Dominique Guenot, Loreley Calvet, Caroline Mignard, Olivier Duchamp, Thomas Carton, Sébastien Leuillet, Hervé M. Blottière, Françoise Le Vacon. Impact of chemotherapy on the intestinal microbiome and epithelial barrier in PDX models of lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 662.

Histo-blood group antigen-binding specificities of human rotaviruses are associated with gastroenteritis but not with in vitro infection

Human strains of rotavirus A (RVAs) recognize fucosylated glycans belonging to histo-blood group antigens (HBGAs) through their spike protein VP8*. Lack of these ligands due to genetic polymorphisms is associated with resistance to gastroenteritis caused by P[8] genotype RVAs. With the aim to delineate the contribution of HBGAs in the process, we analyzed the glycan specificity of VP8* proteins from various P genotypes. Binding to saliva of VP8* from P[8] and P[4] genotypes required expression of both FUT2 and FUT3 enzymes, whilst binding of VP8* from the P[14] genotype required FUT2 and A enzymes. We further defined a glycan motif, GlcNAcβ3Galβ4GlcNAc, recognized by P[6] clinical strains. Conversion into Lewis antigens by the FUT3 enzyme impaired recognition, explaining their lower binding to saliva of Lewis positive phenotype. In addition, the presence of neutralizing antibodies was associated with the presence of the FUT2 wild type allele in sera from young healthy adults. Nonetheless, in vitro infection of transformed cell lines was independent of HBGAs expression, indicating that HBGAs are not human RV receptors. The match between results from saliva-based binding assays and the epidemiological data indicates that the polymorphism of human HBGAs controls susceptibility to RVAs, although the exact mechanism remains unclear.

Differences in Treating Tobacco Use Across National, State, and Public Hospital System Surveys

The Louisiana Tobacco Control Initiative (TCI), a multidisciplinary program specializing in helping tobacco users quit, assisted health care providers in Louisiana’s public hospitals with integrating evidence-based treatment of tobacco use into clinical practice. Our study compared smoking behavior, provider adherence to the 5 A’s tobacco cessation intervention (ask, advise, assess, assist, and arrange), cessation assistance awareness, quit attempts, and treatment preference among respondents to a TCI survey with a sample of respondents from the National Adult Tobacco Survey (NATS) and a sample from the Louisiana Adult Tobacco Survey (LATS). In 2010, more TCI respondents were asked if they smoked, advised to quit, helped to set a quit date, counseled, and arranged to be contacted for follow-up than respondents to NATS or LATS. Fewer TCI respondents received self-help material or were prescribed medication to assist in quitting than NATS and LATS respondents. In 2010 and 2013, TCI participants reported more quit attempts when 4 or more of the 5 A’s were received. Thus, public health systems can promote treatment of tobacco use.

Towards standards for human fecal sample processing in metagenomic studies

Technical variation in metagenomic analysis must be minimized to confidently assess the contributions of microbiota to human health. Here we tested 21 representative DNA extraction protocols on the same fecal samples and quantified differences in observed microbial community composition. We compared them with differences due to library preparation and sample storage, which we contrasted with observed biological variation within the same specimen or within an individual over time. We found that DNA extraction had the largest effect on the outcome of metagenomic analysis. To rank DNA extraction protocols, we considered resulting DNA quantity and quality, and we ascertained biases in estimates of community diversity and the ratio between Gram-positive and Gram-negative bacteria. We recommend a standardized DNA extraction method for human fecal samples, for which transferability across labs was established and which was further benchmarked using a mock community of known composition. Its adoption will improve comparability of human gut microbiome studies and facilitate meta-analyses.

Abstract LB-172: Chemotherapy impact on the gut microbiota: clinical trial on patients

The French Consortium IMODI (Innovative MODels Initiative) aims to develop predictive preclinical mouse models for new chemotherapeutic treatment discovery, to progress toward personalized medicine. In this consortium, Biofortis Merieux NutriSciences issue is to better understand the relation between gut microbiota and cancer, particularly during chemotherapeutic treatment. Because chemotherapy can lead to disruption in microbiota composition and several side effects, our purpose is to identify and track the impact of chemotherapy treatment on the gut microbiota.

To this aim, we coordinate a clinical study to recruit patients with four types of cancer (breast, ovary, liver and prostate) from 7 clinical centers. Gut microbiota composition is assessed by targeted metagenomic, from patient stool samples, collected before, during and after chemotherapy. The 16S rDNA sequences will be analyzed using an in-house bioinformatic pipeline based on mothur software.

Interestingly, preliminary results from preclinical studies showed that some chemotherapeutic treatments could have an effect on gut microbiota composition associated with weight loss. These results support that microbiota is an important additional parameter for evaluating the efficacy and the toxicity of pharmacological treatments. The clinical study is ongoing to better understand the effect of chemotherapy on the gut microbiota. This approach may lead to beneficial intervention for cancer patients, particularly to minimize side effects and infectious complications.

Note: This abstract was not presented at the meeting.

Citation Format: Cindy Pensec, Alessandra De Martino, Laure-Anne Serres, IMODI consortium, Yao Amouzou, Sebastien Leuillet, Mario campone, Thomas Carton, Françoise LE VACON. Chemotherapy impact on the gut microbiota: clinical trial on patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-172. doi:10.1158/1538-7445.AM2017-LB-172

Beyond Food Access: The Impact of Parent-, Home-, and Neighborhood-Level Factors on Children's Diets

Despite the growth in empirical research on neighborhood environmental characteristics and their influence on children’s diets, physical activity, and obesity, much remains to be learned, as few have examined the relationship between neighborhood food availability on dietary behavior in children, specifically. This analysis utilized data from a community-based, cross-sectional sample of children (n = 199) that was collected in New Orleans, Louisiana, in 2010. This dataset was linked to food environment data to assess the impact of neighborhood food access as well as household and parent factors on children’s diets. We observed a negligible impact of the neighborhood food environment on children’s diets, except with respect to fast food, with children who had access to fast food within 500 m around their home significantly less likely (OR = 0.35, 95% CI: 0.1, 0.8) to consume vegetables. Key parental and household factors did play a role in diet, including receipt of public assistance and cooking meals at home. Children receiving public assistance were 2.5 times (95% CI: 1.1, 5.4) more likely to consume fruit more than twice per day compared with children not receiving public assistance. Children whose family cooked dinner at home more than 5 times per week had significantly more consumption of fruit (64% vs. 58%) and vegetables (55% vs. 39%), but less soda (27% vs. 43%). Findings highlight the need for future research that focuses on the dynamic and complex relationships between built and social factors in the communities and homes of children that impact their diet in order to develop multilevel prevention approaches that address childhood obesity.

The Building Blocks of Interoperability. A Multisite Analysis of Patient Demographic Attributes Available for Matching

BACKGROUND

Patient matching is a key barrier to achieving interoperability. Patient demographic elements must be consistently collected over time and region to be valuable elements for patient matching.

OBJECTIVES

We sought to determine what patient demographic attributes are collected at multiple institutions in the United States and see how their availability changes over time and across clinical sites.

METHODS

We compiled a list of 36 demographic elements that stakeholders previously identified as essential patient demographic attributes that should be collected for the purpose of linking patient records. We studied a convenience sample of 9 health care systems from geographically distinct sites around the country. We identified changes in the availability of individual patient demographic attributes over time and across clinical sites.

RESULTS

Several attributes were consistently available over the study period (2005-2014) including last name (99.96%), first name (99.95%), date of birth (98.82%), gender/sex (99.73%), postal code (94.71%), and full street address (94.65%). Other attributes changed significantly from 2005-2014: Social security number (SSN) availability declined from 83.3% to 50.44% (p<0.0001). Email address availability increased from 8.94% up to 54% availability (p<0.0001). Work phone number increased from 20.61% to 52.33% (p<0.0001).

CONCLUSIONS

Overall, first name, last name, date of birth, gender/sex and address were widely collected across institutional sites and over time. Availability of emerging attributes such as email and phone numbers are increasing while SSN use is declining. Understanding the relative availability of patient attributes can inform strategies for optimal matching in healthcare.

A mixture of milk and vegetable lipids in infant formula changes gut digestion, mucosal immunity and microbiota composition in neonatal piglets

PURPOSE

Although composition of infant formula has been significantly improved during the last decade, major differences with the composition and structure of breast milk still remain and might affect nutrient digestion and gut biology. We hypothesized that the incorporation of dairy fat in infant formulas could modify their physiological impacts by making their composition closer to that of human milk. The effect of milk fat and milk fat globule membrane (MFGM) fragments in infant formulas on gut digestion, mucosal immunity and microbiota composition was evaluated.

METHODS

Three formulas containing either (1) vegetable lipids stabilized only by proteins (V-P), (2) vegetable lipids stabilized by a mixture of proteins and MFGM fragments (V-M) and (3) a mixture of milk and vegetable lipids stabilized by a mixture of proteins and MFGM fragments (M-M) were automatically distributed to 42 newborn piglets until slaughter at postnatal day (PND) 7 or 28, and compared to a fourth group of sow's suckling piglets (SM) used as a breast-fed reference.

RESULTS

At both PND, casein and β-lactoglobulin digestion was reduced in M-M proximal jejunum and ileum contents compared to V-P and V-M ones leading to more numerous β-Cn peptides in M-M contents. The IFNγ cytokine secretion of ConA-stimulated MLN cells from M-M piglets tended to be higher than in V-P ones at PND 7 and PND 28 and was closer to that of SM piglets. No dietary treatment effect was observed on IL-10 MLN cell secretion. Changes in faecal microbiota in M-M piglets resulted in an increase in Proteobacteria and Bacteroidetes and a decrease in Firmicutes phyla compared to V-P ones. M-M piglets showed higher abundances of Parabacteroides, Escherichia/Shigella and Klebsiella genus.

CONCLUSIONS

The incorporation of both milk fat and MFGM fragments in infant formula modifies protein digestion, the dynamic of the immune system maturation and the faecal microbiota composition.

Tobacco Policies in Louisiana: Recommendations for Future Tobacco Control Investment from SimSmoke, a Policy Simulation Model

Despite the presence of tobacco control policies, Louisiana continues to experience a high smoking burden and elevated smoking-attributable deaths. The SimSmoke model provides projections of these health outcomes in the face of existing and expanded (simulated) tobacco control polices. The SimSmoke model utilizes population data, smoking rates, and various tobacco control policy measures from Louisiana to predict smoking prevalence and smoking-attributable deaths. The model begins in 1993 and estimates are projected through 2054. The model is validated against existing Louisiana smoking prevalence data. The most powerful individual policy measure for reducing smoking prevalence is cigarette excise tax. However, a comprehensive cessation treatment policy is predicted to save the most lives. A combination of tobacco control policies provides the greatest reduction in smoking prevalence and smoking-attributable deaths. The existing Louisiana excise tax ranks as one of the lowest in the country and the legislature is against further increases. Alternative policy measures aimed at lowering prevalence and attributable deaths are: cessation treatments, comprehensive smoke-free policies, and limiting youth access. These three policies have a substantial effect on smoking prevalence and attributable deaths and are likely to encounter more favor in the Louisiana legislature than increasing the state excise tax.

16S rRNA gene pyrosequencing reveals shift in patient faecal microbiota during high-dose chemotherapy as conditioning regimen for bone marrow transplantation

Gastrointestinal disturbances are a side-effect frequently associated with haematological malignancies due to the intensive cytotoxic treatment given in connection with bone marrow transplantation (BMT). However, intestinal microbiota changes during chemotherapy remain poorly described, probably due to the use of culture-based and low-resolution molecular methods in previous studies. The objective of our study was to apply a next generation DNA sequencing technology to analyse chemotherapy-induced changes in faecal microbiota. We included eight patients with non-Hodgkin's lymphoma undergoing one course of BMT conditioning chemotherapy. We collected a prechemotherapy faecal sample, the day before chemotherapy was initiated, and a postchemotherapy sample, collected 1 week after the initiation of chemotherapy. Total DNA was extracted from faecal samples, denaturing high-performance liquid chromatography based on amplification of the V6 to V8 region of the 16S ribosomal RNA (rRNA) gene, and 454-pyrosequencing of the 16 S rRNA gene, using PCR primers targeting the V5 and V6 hypervariable 16S rRNA gene regions were performed. Raw sequence data were screened, trimmed, and filtered using the QIIME pipeline. We observed a steep reduction in alpha diversity and significant differences in the composition of the intestinal microbiota in response to chemotherapy. Chemotherapy was associated with a drastic drop in Faecalibacterium and accompanied by an increase of Escherichia. The chemotherapy-induced shift in the intestinal microbiota could induce severe side effects in immunocompromised cancer patients. Our study is a first step in identifying patients at risk for gastrointestinal disturbances and to promote strategies to prevent this drastic shift in intestinal microbiota.

The louisiana clinical data research network: leveraging regional and national resources to improve clinical research efficiency

BACKGROUND

Mapping of the human genome and technological advancements allowing storage and rapid retrieval of healthcare data have heralded a new phase in clinical medicine and have served as a catalyst for the advent of personalized medicine. The use of health information databases provides a unique opportunity to investigate questions of great complexity and real-world application in a way that is most useful in providing high quality, safe, and cost-effective clinical care to patients.

METHODS

The Louisiana Clinical Data Research Network (LACDRN) aims to streamline the workflow of multiinstitutional clinical studies and to dramatically expand the clinical research resources available to local investigators. The LACDRN contains health information for more than 1 million patients in Southeast Louisiana and is a rich resource for researchers to conduct retrospective or observational trials and to recruit patients for prospective studies.

RESULTS

The LACDRN is part of a large-scale initiative by the Patient-Centered Outcomes Research Institute to create a national electronic health record network that enables the timely initiation and completion of comparative effectiveness research in a coordinated effort. For the first time, network research will be guided in part by input from patients and caregivers, increasing their engagement in the research process.

CONCLUSION

The establishment of the LACDRN is a unique opportunity for clinicians to take part in an innovative national initiative designed to offer new clinical research options for patients and to carry out cutting-edge translational, clinical, and health services research.

Beneficial effects of probiotics in upper respiratory tract infections and their mechanical actions to antagonize pathogens

Probiotics are live micro‐organisms with beneficial effects on human health, which have the ability to counteract infections at different locations of the body. Clinical trials have shown that probiotics can be used as preventive and therapeutic agents in upper respiratory tract infections (URTIs) and otitis. Their mechanical properties allow them to aggregate and to compete with pathogens for nutrients, space and attachment to host cells. Consequently, they can directly antagonize pathogens and thus exert beneficial effects without directly affecting the metabolism of the host. An overview of the probiotics with such traits, tested up to date in clinical trials for the prevention or treatment of URTIs and otitis, is presented in this review. Their mechanical properties in the respiratory tract as well as at other locations are also cited. Species with interesting in vitro properties towards pharyngeal cells or against common respiratory pathogens have also been included. The potential safety risks of the cited species are then discussed. This review could be of help in the screening of probiotic strains with specific mechanical properties susceptible to have positive effects in clinical trials against URTIs.

Application of denaturing high-performance liquid chromatography (DHPLC) for the identification of fish: a new way to determine the composition of processed food containing multiple species

The identification of fish species in transformed food products is difficult because the existing methods are not adapted to heat-processed products containing more than one species. Using a common to all vertebrates region of the cytochrome b gene, we have developed a denaturing high-performance liquid chromatography (DHPLC) fingerprinting method, which allowed us to identify most of the species in commercial crab sticks. Whole fish and fillets were used for the creation of a library of referent DHPLC profiles. Crab sticks generated complex DHPLC profiles in which the number of contained fish species can be estimated by the number of major fluorescence peaks. The identity of some of the species was predicted by comparison of the peaks with the referent profiles, and others were identified after collection of the peak fractions, reamplification, and sequencing. DHPLC appears to be a quick and efficient method to analyze the species composition of complex heat-processed fish products.

Application of denaturing high-performance liquid chromatography for intestinal microbiota analysis of newborns

AIMS

Neonatal microbiota development seems to play a key role in the early origins of health and disease. However, the analysis of this complex ecosystem is still difficult. The aim of this work was to investigate the feasibility of a new technique, denaturing high-performance liquid chromatography (dHPLC), to analyze newborn intestinal microbiota using genomic approaches.

METHODS AND RESULTS

Eleven neonates were recruited among patients admitted for intestinal surgery to the neonatal intensive care unit. Preoperative samplings were obtained in each case. Three methodologies were compared for each sample: (i) dHPLC, (ii) temporal temperature gradient gel electrophoresis (TTGE), and (iii) conventional culture techniques.

RESULTS

All samples were poorly colonized. In three samples, the microbiota was detected only with the dHPLC technique. Results obtained with culture and TTGE could be found with dHPLC.

CONCLUSION

The results suggest that neonatal applications of the dHPLC technique, especially for gut microbiota analysis, appear to be a sensitive and promising analytical technique.

Human intestinal microbiota gene risk factors for antibiotic-associated diarrhea: perspectives for prevention. Risk factors for antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is associated with altered intestinal microflora and other symptoms that may lead to possibly death. In critically ill patients, diarrhea increases rates of morbimortality. Assessing diarrhea risks is thus important for clinicians. For this reason, we conducted a hypothesis-generating study focused on AAD to provide insight into methods of prevention. We evaluated the hypothesis of predisposing factors within the resident intestinal microbiota in a cohort of outpatients receiving antibiotherapy. Among the pool of tested variables, only those related to bacterial 16S rRNA genes were found to be relevant. Complex statistical analyses provided further information: amid the bacteria 16S rRNA genes, eight were determined to be essential for diarrhea predisposition and characterized from the most important to the least. Using these markers, AAD risk could be estimated with an error of 2%. This molecular analysis offers new perspectives for clinical applications at the level of prevention.

Use of genotypic selection to detect P53 codon 273 CGT>CTT transversion: application to an occupationally exposed population

CGT>CTT transversion in codon 273 of the P53 tumor-suppressor gene is one of the major mutations detected in human tumors. Within an epidemiological framework, we investigated the use of a genotypic selection method to measure this point mutation. The allele-specific polymerase chain reaction (AS-PCR) that was developed was able to detect 10 mutant copies of the gene among a total of 5 x 10(5) wild-type copies. We used this assay to detect CGT>CTT transversions in buccal cell DNA of production workers (n=76) from a viscose factory exposed to carbon disulfide (amongst other pollutants) and in the DNA of non-exposed office workers (n=67). The mutation appeared more frequently in the exposed than in the non-exposed worker who were smokers. The results of the study indicate that occupational exposure results in a significant increase in P53 CGT>CTT transversions and more especially identified occupational exposure in combination with smoking as a significant risk factor for the mutation. We conclude that AS-PCR of the P53 273rd codon transversions is a suitable technique for studying the effects of occupational exposure.