# Epidemiology and clinical profile of diarrhea associated with enterotoxigenic Escherichia coli and Vibrio cholerae in Bangladesh: Findings from a hospital-based surveillance system, 2008–2023

## TL;DR

This study examines how infections with ETEC and Vibrio cholerae, alone or together, affect the severity of diarrhea in hospitalized patients in Bangladesh.

## Contribution

The study provides new insights into the clinical severity and epidemiology of co-infections with ETEC and Vibrio cholerae in a hospital setting.

## Key findings

- Co-infection with ETEC and Vibrio cholerae is associated with more severe symptoms and higher odds of requiring intravenous rehydration.
- Vibrio cholerae infections are more severe than ETEC infections in terms of dehydration and hospital stay duration.
- The frequency of co-infections increased to 7.5% in 2023, highlighting a growing clinical concern.

## Abstract

Enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae are notable enteric bacterial pathogens that cause diarrheal illnesses in resource-limited settings (e.g., Bangladesh). We aimed to explore the epidemiology and the clinical presentation of diarrhea caused by either V. cholerae or ETEC as a single-pathogen, or as a co-infection with both pathogens among patients requiring hospitalization.

We conducted the study using data from the Diarrheal Diseases Surveillance System of Dhaka Hospital, icddr,b from 2008 to 2023. A multivariable logistic regression model was used to characterize association of identified bacterial pathogens with specific clinical features.

Among 43,483 diarrheal patients who received hospital care, 11% (4540/43,483) tested positive for V. cholerae, 8% (3070/43,483) had ETEC, and 1.5% (630/43,483) had co-infection. In 2023, the frequencies of ETEC, V. cholerae, and co-infection with both pathogens among patients were 7.5%, 4.5%, and 7.5%, respectively. After adjusting for covariates, co-infected cases showed significantly higher odds of severe outcomes, including watery stools (aOR: 12.33), high stooling frequency (>10/day, aOR: 1.50), vomiting (aOR: 3.16), and intravenous rehydration (aOR: 8.70) compared to single-pathogen infections. Clinical features among patients infected with single pathogens also varied. V. cholerae-positive cases were associated with dehydration [aOR:5.64;95%CI:(4.94,6.43)] and length of hospital stay [aOR:1.81;95%CI:(1.68,1.94)] relative to V. cholerae-negative cases. ETEC-positive cases were more likely to present with watery stools [aOR:1.26;95%CI:(1.04,1.53)], dehydration [aOR:1.23;95%CI:(1.12,1.35)], and the requirement for intravenous fluid rehydration [aOR:1.15;95%CI:(1.04,1.27)] relative to ETEC-negative cases. Overall, the clinical presentations of patients with ETEC single infection were less severe compared to patients with V. cholerae as a single infection or co-infection.

Co-infection with V. cholerae and ETEC results in more severe clinical manifestations requiring intensive medical management compared to single-pathogen infections. These findings highlight the need for enhanced clinical preparedness and consideration of testing for both pathogens to optimize patient care. Our findings highlight the potential value of vaccines targeting ETEC and V. cholerae to improve protection.

Diarrheal diseases continue to pose significant public health challenges, particularly in low- and middle-income countries (LMICs). Approximately 1.5 million deaths worldwide are attributed to diarrheal diseases. Enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae are notably frequent enteric bacterial pathogens that cause diarrheal illnesses in resource-limited settings (e.g., Bangladesh). This study was undertaken using a robust dataset from the largest diarrheal disease hospital, spanning 16 years. This approach allowed us to analyze trends, patterns, and changes over time. This study describes the epidemiology and the clinical presentation of diarrhea caused by either V. cholerae or ETEC as a single-pathogen, or as a co-infection with both pathogens, among patients requiring hospitalization. This research focused on a particular location in South Asia, urban Bangladesh. But ETEC and Vibrio cholerae are global pathogens. This study’s findings are relevant for appreciating the problems faced by people who experience illness caused by these pathogens, particularly those who live in cities in LIMCs. These findings highlight the need for enhanced clinical preparedness and consideration of testing for both pathogens to optimize patient care. Our findings also highlight the potential value of vaccines targeting ETEC and V. cholerae to improve protection.