New Tools to Test Stool: Managing Travelers' Diarrhea in the Era of Molecular Diagnostics

Injuries and medical emergencies among international travellers

BACKGROUND

Tropical infectious diseases and vaccine-preventable emergencies are the mainstay of pre-travel consultations. However, non-communicable diseases, injuries and accidents that occur during travel are not emphasized enough in these settings.

METHODS

We performed a narrative review based on a literature search of PubMed, Google Scholar, UpToDate, DynaMed and LiSSa and on reference textbooks and medical journals dedicated to travel, emergency and wilderness medicine. Relevant secondary references were extracted. We also aimed to discuss newer or neglected issues, such as medical tourism, Coronavirus Disease 2019, exacerbations of co-morbidities associated with international travel, insurance coverage, health care seeking abroad, medical evacuation or repatriation and tips for different types of travellers' emergency medical kits (personal, group, physician handled).

RESULTS

All sources reviewed led to the selection of >170 references. Among epidemiological data on morbidity and deaths while abroad, only retrospective data are available. Deaths are estimated to occur in 1 in 100 000 travellers, with 40% caused by trauma and 60% by diseases, and <3% linked to infectious diseases. Trauma and other injuries acquired during travel, such as traffic accidents and drowning, can be reduced by up to 85% with simple preventive recommendations such as avoiding simultaneous alcohol intake. In-flight emergencies occur on 1 in 604 flights on average. Thrombosis risk is two to three times greater for travellers than for non-travellers. Fever during or after travel can occur in 2-4% of travellers, but in up to 25-30% in tertiary centres. Traveller's diarrhoea, although rarely severe, is the most common disease associated with travel. Autochthonous emergencies (acute appendicitis, ectopic pregnancy, dental abscess) can also occur.

CONCLUSIONS

Pre-travel medicine encounters must include the topic of injuries and medical emergencies, such as the risk-taking behaviours and foster better planning in a comprehensive approach along with vaccines and infectious diseases advices.

Bacterial travellers' diarrhoea: A narrative review of literature published over the past 10 years

Travellers' diarrhoea (TD) is the most frequent illness experienced by international travellers to lower-income countries with bacterial agents considered to account for 80-90% of cases. In this review, we summarise evidence published on bacterial TD over the past 10 years, focusing on the epidemiology and aetiology of TD. Diarrhoeagenic Escherichia coli (DEC) continue to be the most commonly implicated bacteria in TD, although Enteropathogenic E. coli (EPEC) and Enteroaggregative E. coli (EAEC) now appear to be predominant where Enterotoxigenic E. coli (ETEC) was previously considered most prevalent globally. Where fluroquinolone resistance had primarily been documented for Campylobacter in Southeast Asia, widespread resistance has been observed in most regions of the world for multiple enteropathogens, including Shigella, Salmonella, ETEC and EAEC. Implementation of novel molecular methods for pathogen detection has led to identification of bacterial pathogens, including Clostridium difficile (with and without the use of prior antibiotics), Arcobacter species and Bacteroides fragilis, as aetiological agents in TD. The widespread resistance to first-line antibiotics in multiple bacterial enteropathogens warrants continued surveillance and re-evaluation of current treatment practices. Further investigations are required to determine the prevalence and geographical distribution of bacterial enteropathogens that have been more recently implicated in TD.

A comparison of two multiplex-PCR assays for the diagnosis of traveller's diarrhoea

Background

Numerous multiplex-PCR assays are now available in routine diagnostics but their clinical value is controversial if a clear association between clinical symptoms and the detection of a particular pathogen is missing. The objective of this work was to evaluate a multiplex-PCR assay for the diagnosis of traveller’s diarrhoea (TD) in a case-control study and to assess the concordance with the BioFire® FilmArray® Gastrointestinal Panel.

Methods

Stool samples from cases (n = 61) and controls (n = 30) were collected during travel and analysed by the GI-EB Screening assay (Seegene) in a case-control study. The concordance with the BioFire® FilmArray® Gastrointestinal Panel was expressed as the proportion of participants in which both tests agreed in the category “detected” and “not detected”.

Results

None of the test-target organisms (Campylobacter spp., Clostridioides difficile toxin A/B, Salmonella spp., Shigella spp./enteroinvasive Escherichia coli, E. coli O157, Shiga toxin-producing E. coli, Yersinia enterocolitica) was significantly associated with TD GI-EB Screening assay. The GI-EB Screening assay had an agreement with the BioFire® FilmArray® of 86.8–100%.

Conclusion

The selection of test-target organisms included in the GI-EB Screening assay appears inappropriate for the diagnostic work-up of TD as none of the detected pathogens was associated with TD. The GI-EB Screening assay had a good concordance with BioFire® FilmArray®.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05885-3.

Description of Enteropathic Escherichia coli Species in Pediatric Patients at a Quaternary Children's Hospital

BACKGROUND

The epidemiology, demographics, clinical presentations, and outcomes associated with enteroaggregative Escherichia coli (EAEC), enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC) pathotypes in US children are not well understood.

METHODS

This study was a retrospective chart review of all pediatric patients with a stool sample submitted to the Children's Hospital Colorado clinical microbiology laboratory for testing with the BioFire FilmArray Gastrointestinal Pathogen Panel from October 2015 through October 2017.

RESULTS

During the study period, 5692 patient stool samples were submitted; 679 (13%) were positive for EAEC, EPEC, or ETEC. Of note, 163/232 (70%) patients with EAEC, 282/493 (57%) with EPEC, and 49/58 (85%) with ETEC had detection of at least 1 other pathogen. Of all E. coli-positive stool samples, only 158/679 (23%) were from low-risk patients who were singly infected with EAEC, EPEC, or ETEC. In this cohort, most cases were associated with acute diarrhea (50%), abdominal pain (61%), and/or cramping (49%) and presented without fever (14%), emesis (28%), or lethargy (7%). Thirteen (8%) of these 158 patients received antibiotics at the time of their initial presentation to care. Of the 145 patients who did not receive antibiotics at their initial visit, 23 (16%) returned to care due to persistence of symptoms.

CONCLUSIONS

Our results suggest that the majority of patients singly infected with EAEC, EPEC, or ETEC present with mild, self-limited, gastrointestinal (GI) complaints. Further research is needed to determine what role these pathogens might play in children who present with chronic or inflammatory GI symptoms.

Efficacy of stool multiplex polymerase chain reaction assay in adult patients with acute infectious diarrhea

BACKGROUND

Recently, stool multiplex polymerase chain reaction (PCR) tests have been developed for identifying diarrhea-causing bacterial pathogens. Furthermore, fecal calprotectin is a well-known effective marker for intestinal mucosal inflammation.

AIM

To evaluate the efficacy of stool multiplex PCR and fecal calprotectin in acute infectious diarrhea.

METHODS

Overall, 400 patients with acute infectious diarrhea were enrolled from Kangdong Sacred Heart Hospital (January 2016 to December 2018). Multiplex PCR detected 7 enteropathogenic bacteria including Salmonella, Campylobacter, Shigella, Escherichia coli O157:H7, Aeromonas, Vibrio, and Clostridium difficile. We reviewed clinical and laboratory findings using stool multiplex PCR.

RESULTS

Stool multiplex PCR test detected considerably more bacterial pathogens than stool culture (49.2% vs 5.2%), with Campylobacter as the most common pathogen (54%). Patients with positive stool PCR showed elevated fecal calprotectin expression compared to patients with negative stool PCR (1124.5 ± 816.9 mg/kg vs 609 ± 713.2 mg/kg, P = 0.001). C-reactive protein (OR = 1.01, 95%CI: 1.001-1.027, P = 0.034) and sigmoidoscopy-detected colitis (OR = 4.76, 95%CI: 1.101-20.551, P = 0.037) were independent factors in stool PCR-based detection of bacterial pathogens. Sensitivity and specificity of calprotectin were evaluated to be 70.5% and 60.9%, respectively (adjusted cut-off value = 388 mg/kg).

CONCLUSION

Stool multiplex PCR test has increased sensitivity in detecting pathogens than conventional culture, and it is correlated with calprotectin expression. Stool multiplex PCR and calprotectin may be effective in predicting clinical severity of infectious diarrhea.