Gut microbiome and antibiotic resistance effects during travelers' diarrhea treatment and prevention.

IMPORTANCE: The travelers' gut microbiome is potentially assaulted by acute and chronic perturbations (e.g., diarrhea, antibiotic use, and different environments). Prior studies of the impact of travel and travelers' diarrhea (TD) on the microbiome have not directly compared antibiotic regimens, and studies of different antibiotic regimens have not considered travelers' microbiomes. This gap is important to be addressed as the use of antibiotics to treat or prevent TD-even in moderate to severe cases or in regions with high infectious disease burden-is controversial based on the concerns for unintended consequences to the gut microbiome and antimicrobial resistance (AMR) emergence. Our study addresses this by evaluating the impact of defined antibiotic regimens (single-dose treatment or daily prophylaxis) on the gut microbiome and resistomes of deployed servicemembers, using samples collected during clinical trials. Our findings indicate that the antibiotic treatment regimens that were studied generally do not lead to adverse effects on the gut microbiome and resistome and identify the relative risks associated with prophylaxis. These results can be used to inform therapeutic guidelines for the prevention and treatment of TD and make progress toward using microbiome information in personalized medical care.

Evaluating SARS-CoV-2 Saliva and Dried Blood Spot Surveillance Strategies in a Congregate Population.

The optimal approach to COVID-19 surveillance in congregate populations remains unclear. Our study at the US Naval Academy in Annapolis, Maryland, USA, assessed the concordance of antibody prevalence in longitudinally collected dried blood spots and saliva in a setting of frequent PCR-based testing. Our findings highlight the utility of salivary-based surveillance.

The Burden of Arboviral Infections in the Military Health System 2012-2019.

Arboviral infections, including dengue (DNV), chikungunya (CHIKV), and Zika (ZIKV), impact both travelers and native populations of endemic regions. We sought to assess the disease burden of arboviral infections in the Military Health System, the validity of arboviral diagnostic codes, and the role of pretravel counseling on insect avoidance precautions. We searched for diagnostic codes consistent with arboviral infection and grouped them into DNV, CHIKV, ZIKV, Japanese encephalitis virus (JEV), and Other. Demographic data were evaluated. A subset of charts in each category were reviewed for diagnostic validity and travel characteristics. In all, 10,547 unique subjects carried 17,135 arboviral diagnostic codes, including 1,606 subjects (15.2%) coded for DNV, 230 (2.2%) for ZIKV, 65 (0.6%) for CHIKV, and 4,317 (40.9%) for JEV. A chart review was performed on 807 outpatient charts, yielding outpatient diagnostic code positive predictive values of 60.5% (DNV), 15.3% (ZIKV), and 64.5% (CHIKV); there were no valid cases of JEV. Dengue represented the greatest burden of arboviral infections with 2.2 cases per 100,000 military healthcare enrollees over the 2012-2019 fiscal years. More than 80% of subjects with arboviral infection did not have documented pretravel counseling. Arboviral infections represent a significant disease burden in young travelers to endemic regions. After adjustment for diagnostic validity, DNV represented the greatest burden. Diagnostic codes for ZIKV and JEV overestimate the burden of these diseases. Low rates of pretravel visits represent an opportunity for increased emphasis on insect exposure precautions.

Destination based errors in chloroquine malaria chemoprophylaxis vary based on provider specialty and credentials.

BACKGROUND: The Deployment and Travel Medicine Knowledge, Attitudes, Practices, and Outcomes Study (KAPOS) evaluates health outcomes and provider practices associated with travel and deployments within the US Military Health System. We analyzed prescribing errors for chloroquine malaria chemoprophylaxis between travel medicine specialists and non-specialists over a five-year period. METHODS: A sample of 291 chloroquine prescriptions were reviewed to determine if malaria chemoprophylaxis was appropriate for destination of travel based on both transmission and chloroquine resistance risk. We included non-active-duty beneficiaries of all ages seeking care at military treatment facilities. RESULTS: 10.3% (n = 30) of patients were prescribed chloroquine inappropriately. Non-travel medicine specialists prescribed chloroquine inappropriately more frequently than travel medicine specialists with 16.5% vs 2.3% error, respectively. Physicians were less likely to erroneously prescribe chloroquine as compared to non-physicians with 6.4% vs 22.2% error, respectively. 93.3% of prescribing errors were due to chloroquine-resistance presence at the travel destination. Africa was the most common destination of erroneous prescriptions, creating significant risk for travelers. CONCLUSIONS: While chloroquine is infrequently prescribed, this analysis demonstrates travel medicine proficiency is associated with reduced errors, highlighting the need to supply travel medicine education and decision support tools to non-specialists, to safeguard patients who seek pre-travel medical care.

Military and Civilian Sector Practice Patterns for Short-Term Travelers' Diarrhea Self-Treatment in Adults.

The Deployment and Travel Medicine Knowledge, Attitude, Practice and Outcomes Study investigates the various clinician and traveler contributions to medical outcomes within the U.S. Military Health System. Travelers' diarrhea is among the most common travel-related illnesses, making travelers' diarrhea self-treatment (TDST) important for traveler health. A cohort of 80,214 adult travelers receiving malaria chemoprophylaxis for less than 6 weeks of travel were identified within the U.S. Department of Defense Military Health System Data Repository. Associated prescriptions for TDST medications within 2 weeks of chemoprophylaxis prescriptions were identified. Prescription patterns were compared by service member versus beneficiary status and site of care, military facility versus civilian facility. At military facilities, medical provider demographics were analyzed by clinical specialty and categorized as travel medicine specialists versus nonspecialists. Overall, there was low prescribing of TDST, particularly among civilian providers and military nonspecialists, despite guidelines recommending self-treatment of moderate to severe travelers' diarrhea. This practice gap was largest among service member travelers, but also existed for beneficiaries. Compared with nonspecialists, military travel medicine specialists were more likely to prescribe a combination of an antibiotic and antimotility agent to beneficiaries, more likely to provide any form of TDST to service members, and more likely to prescribe azithromycin than quinolones when using antibiotics. Our study suggests that enhancing provider knowledge and use of travelers' diarrhea treatment recommendations combined with improved access to formal travel medicine services may be important to increase the quality of care.

Costs and Prescribing Patterns of Anthelmintics in the United States Military: A Retrospective Analysis.

BACKGROUND: Recent price increases in medications used to treat helminth infections have had demonstrated impacts on Medicaid and immigrant patient populations. Helminth infections are common within the US military; however, anthelmintic prescribing patterns and costs have not yet been investigated in this patient population. METHODS: We conducted a retrospective analysis of pharmaceutical data from the Military Health System Data Repository between fiscal years 2012 and 2019. Prescription information, including costs and demographics, were abstracted for all anthelmintic medications as well as associated helminth diagnostic codes within 30 days of the prescription dispensing date. RESULTS: On average, there were 10 871 anthelmintic medications prescribed per year, for a total of 86 697 during the study period. Ivermectin and albendazole were each prescribed >34 000 times. There were 15 498 mebendazole prescriptions and 1327 praziquantel prescriptions. The total cost of all anthelmintic prescriptions was $16 018 381. Annual costs for anthelmintic medications increased 16-fold during the study period, up to nearly $5 000 000 in fiscal year 2019, primarily driven by price increases in albendazole and mebendazole. Albendazole prescriptions accounted for $12 282 891 of total costs (76.7%), though only 39.1% of total prescriptions. The most common diagnosis associated with albendazole and mebendazole prescriptions was enterobiasis. CONCLUSIONS: Price increases in anthelmintic medications have significantly impacted the costs borne by the US government for treating parasitic infections. There are a substantial number of anthelmintic prescriptions in the US military health care system annually, suggesting a higher number of helminth infections than previously thought.

A disease severity scale for the evaluation of vaccine and other preventive or therapeutic interventions for travellers' diarrhoea.

BACKGROUND: Travellers' diarrhoea (TD) is the most common travel-related illness with an estimated 10 million people afflicted annually. Outcome measures to assess the efficacy of primary and secondary TD interventions were historically based on diarrhoea frequency with ≥1 associated gastrointestinal symptom. Furthermore, efficacy determination is often made on the presence or absence of TD, rather than on TD illness severity. Current severity classifications are based on subjective consideration of impact of illness on activity. We sought to develop a standardized scoring system to characterize TD severity to potentially apply as a secondary outcome in future field studies. METHODS: Data on multiple signs and symptoms were obtained from a previously published multisite TD treatment trial conducted by the US Department of Defense (TrEAT TD). Correlation, regression and multiple correspondence analyses were performed to assess impact on activity and a TD severity score was established. RESULTS: Numerous signs and symptoms were associated with impaired function, with malaise and nausea most strongly associated [odds ratio (OR) 5.9-44.3, P < 0.0001 and OR 2.8-37.1, P < 0.0001, respectively). Based on co-varying symptomatology, a TD severity score accounting for diarrhoea frequency in addition to several signs and symptoms was a better predictor of negative impact on function than any single sign/symptom (X2 = 127.16, P < 0.001). Additionally, there was a significant difference (P < 0.0001) in the mean TD severity score between those with acute watery diarrhoea (3.9 ± 1.9) and those with dysentery or acute febrile illness (6.2 ± 2.0). CONCLUSIONS: The newly developed disease severity score better predicted a negative impact on activity due to TD than did any single sign or symptom. Incorporating multiple parameters into the TD severity score better captures illness severity and moves the field towards current recommendations for TD management by considering symptoms with high functional impact. Further validation of this score is needed in non-military travellers and other settings.

TaqMan Array Card testing of participant-collected stool smears to determine the pathogen-specific epidemiology of travellers' diarrhoea†.

BACKGROUND: We assessed the compliance with self-collection of stool smears on Whatman® FTA® Elute Card (FTA Card) and detection of travellers' diarrhoea (TD)-associated pathogens by using a quantitative Polymerase Chain Reaction (PCR) assay [customized TaqMan® array card (TAC)] in a prospective, observational cohort of travellers. METHODS: Enrolled travellers documented symptoms on a travel diary and collected an FTA Card during a diarrhoeal episode, or at the end of travel if they remained asymptomatic. TAC testing was performed on FTA Cards from TD cases and 1:1 matched asymptomatic controls and 1:1 matched loose stool cases that did not meet TD criteria. Odds ratios were used to determine the association between detected pathogens and TD. RESULTS: Of 2456 travellers, 484 (19.7%) completed an illness diary and met TD criteria, and 257 (53.1%) collected an FTA Card during the TD episode. FTA Cards were stored for a median of 2 years at room temperature (IQR: 1-4 years) before extraction and testing. The overall TAC detection rate in TD cases was 58.8% (95% CI: 52.5-64.8). Enterotoxigenic Escherichia coli was the most common pathogen in TD cases (26.8%), and 3.5% of samples were positive for norovirus. The odds of detecting TD-associated pathogens in 231 matched cases and asymptomatic controls were 5.4 (95% CI: 3.6-8.1) and 2.0 (95% CI: 1.1-3.7) in 121 matched TD and loose stool cases (P < 0.05). Enteroaggregative E. coli was the most common pathogen detected in asymptomatic controls and loose stool cases. Detection of diarrhoeagenic E. coli, Shigella/enteroinvasive E. coli and Campylobacter spp. was significantly associated with TD. CONCLUSION: FTA Cards are a useful adjunct to traditional stool collection methods for evaluating the pathogen-specific epidemiology of TD in austere environments. Qualitative detection of pathogens was associated with TD. Measures to improve compliance and quality of FTA Card collection with decreased storage duration may further optimize detection.

Performance characteristics of a quantitative PCR assay on repository stool specimens and smeared filter-paper cards.

OBJECTIVE: Stool repositories are a valuable resource for retrospective analyses including quantitative PCR assays to distinguish between asymptomatic shedding and clinical disease. The suitability of archival specimens for this purpose is unclear and requires assessment. We conducted a pilot study to evaluate pathogen detection by TaqMan Array Card (TAC) in travelers' diarrhea (TD) stool specimens stored for 1-13 years, as well as the impact of transporting specimens on Whatman FTA Elute cards (FTA Cards) on detection. RESULTS: The positive percent agreement (PPA) for TAC on stool vs. microbiologic testing was lower than our a priori PPA estimate of 80% for most pathogens: Shigella spp. (100% [95%CI 69-100%]), enterotoxigenic E coli (ETEC) (63% [95%CI 49-75%]), Campylobacter spp. (66% [95%CI 43-85%]) and Norovirus (37% [95%CI 16-61%]). Use of the FTA card resulted in a further reduction of PPA. Our findings suggest that archival specimens may lead to insensitive detection on quantitative PCR assays due to degradation of nucleic acid with prolonged storage, although our limited sample size precluded us from evaluating the impact of storage duration on nucleic acid yield. Additional studies are needed to understand the impact of storage duration on quantitative PCR data.

Epidemiology and associated microbiota changes in deployed military personnel at high risk of traveler's diarrhea.

Travelers' diarrhea (TD) is the most prevalent illness encountered by deployed military personnel and has a major impact on military operations, from reduced job performance to lost duty days. Frequently, the etiology of TD is unknown and, with underreporting of cases, it is difficult to accurately assess its impact. An increasing number of ailments include an altered or aberrant gut microbiome. To better understand the relationships between long-term deployments and TD, we studied military personnel during two nine-month deployment cycles in 2015-2016 to Honduras. To collect data on the prevalence of diarrhea and impact on duty, a total of 1173 personnel completed questionnaires at the end of their deployment. 56.7% reported reduced performance and 21.1% reported lost duty days. We conducted a passive surveillance study of all cases of diarrhea reporting to the medical unit with 152 total cases and a similar pattern of etiology. Enteroaggregative E. coli (EAEC, 52/152), enterotoxigenic E. coli (ETEC, 50/152), and enteropathogenic E. coli (EPEC, 35/152) were the most prevalent pathogens detected. An active longitudinal surveillance of 67 subjects also identified diarrheagenic E. coli as the primary etiology (7/16 EPEC, 7/16 EAEC, and 6/16 ETEC). Eleven subjects were recruited into a nested longitudinal substudy to examine gut microbiome changes associated with deployment. A 16S rRNA amplicon survey of fecal samples showed differentially abundant baseline taxa for subjects who contracted TD versus those who did not, as well as detection of taxa positively associated with self-reported gastrointestinal distress. Disrupted microbiota was also qualitatively observable for weeks preceding and following the incidents of TD. These findings illustrate the complex etiology of diarrhea amongst military personnel in deployed settings and its impacts on job performance. Potential factors of resistance or susceptibility can provide a foundation for future clinical trials to evaluate prevention and treatment strategies.

A Comparison of Stool Enteropathogen Detection by Semiquantitative PCR in Adults With Acute Travelers' Diarrhea Before and 3 Weeks After Successful Antibiotic Treatment.

We evaluated stool enteropathogen detection by semiquantitative polymerase chain reaction (PCR) in 108 subjects with travelers' diarrhea before and 3 weeks after treatment. Stool samples from 21 subjects were positive for the same pathogen species at both visits. We discuss factors that should be considered when interpreting stool PCR data after treatment.

Comparison of stool collection and storage on Whatman FTA Elute cards versus frozen stool for enteropathogen detection using the TaqMan Array Card PCR assay.

The use of Polymerase Chain Reaction (PCR) assays for pathogen detection in travelers' diarrhea (TD) field studies is limited by the on-site processing and storage requirements for fecal specimens. The objectives of this investigation were to i) characterize the pathogen distribution in deployed military personnel with TD using the TaqMan® Array Card PCR (TAC) on frozen stool and diarrheal smears on Whatman FTA Elute cards (FTA cards), and to ii) compare TAC detection of enteropathogen targets using smeared FTA cards and frozen stool, using TAC on frozen stool as the 'reference standard'. Stool samples, obtained from active duty personnel with acute TD enrolled in a field trial, were smeared onto FTA cards and stored at room temperature. A corresponding aliquot of stool was frozen in a cryovial. FTA cards and frozen stool samples were tested at a central lab, using a customized TAC for detection of TD pathogens. 187 paired frozen stool samples and smeared FTA cards were stored for a median of 712 days (IQR 396-750) before testing. Overall detection rates were 78.6% for frozen stool and 73.2% for FTA cards. Diarrheagenic Escherichia coli were the most common bacteria identified. Using the TAC results on frozen stool as the reference, the overall sensitivity and specificity of TAC on FTA cards was 72.9% and 98.0% respectively. TAC on FTA cards demonstrated a decrease in sensitivity with increasing frozen stool quantification cycle (Cq) (90.0% in FTA cards with a corresponding frozen stool Cq < 30, and 72.9% in samples with a corresponding frozen stool Cq < 35). Our findings support the use and further development of FTA cards in combination with a quantitative PCR assay for enteropathogen detection in TD field studies.

Rehabilitation of traumatic brain injury in active duty military personnel and veterans: Defense and Veterans Brain Injury Center randomized controlled trial of two rehabilitation approaches.

OBJECTIVES: To determine the relative efficacy of 2 different acute traumatic brain injury (TBI) rehabilitation approaches: cognitive didactic versus functional-experiential, and secondarily to determine relative efficacy for different patient subpopulations. DESIGN: Randomized, controlled, intent-to-treat trial comparing 2 alternative TBI treatment approaches. SETTING: Four Veterans Administration acute inpatient TBI rehabilitation programs. PARTICIPANTS: Adult veterans or active duty military service members (N=360) with moderate to severe TBI. INTERVENTIONS: One and a half to 2.5 hours of protocol-specific cognitive-didactic versus functional-experiential rehabilitation therapy integrated into interdisciplinary acute Commission for Accreditation of Rehabilitation Facilities-accredited inpatient TBI rehabilitation programs with another 2 to 2.5 hours daily of occupational and physical therapy. Duration of protocol treatment varied from 20 to 60 days depending on the clinical needs and progress of each participant. MAIN OUTCOME MEASURES: The 2 primary outcome measures were functional independence in living and return to work and/or school assessed by independent evaluators at 1-year follow-up. Secondary outcome measures consisted of the FIM, Disability Rating Scale score, and items from the Present State Exam, Apathy Evaluation Scale, and Neurobehavioral Rating Scale. RESULTS: The cognitive-didactic and functional-experiential treatments did not result in overall group differences in the broad 1-year primary outcomes. However, analysis of secondary outcomes found differentially better immediate posttreatment cognitive function (mean+/-SD cognitive FIM) in participants randomized to cognitive-didactic treatment (27.3+/-6.2) than to functional treatment (25.6+/-6.0, t332=2.56, P=.01). Exploratory subgroup analyses found that younger participants in the cognitive arm had a higher rate of returning to work or school than younger patients in the functional arm, whereas participants older than 30 years and those with more years of education in the functional arm had higher rates of independent living status at 1 year posttreatment than similar patients in the cognitive arm. CONCLUSIONS: Results from this large multicenter randomized controlled trial comparing cognitive-didactic and functional-experiential approaches to brain injury rehabilitation indicated improved but similar long-term global functional outcome. Participants in the cognitive treatment arm achieved better short-term functional cognitive performance than patients in the functional treatment arm. The current increase in war-related brain injuries provides added urgency for rigorous study of rehabilitation treatments. (http://ClinicalTrials.gov ID# NCT00540020.).