# Prevalence of Escherichia coli and Salmonella spp. in Colombian Pig Production Settings: A One Health Perspective Study

## TL;DR

This study found high levels of harmful bacteria in Colombian pig farms and slaughterhouses, suggesting water is a key source of contamination and highlighting the need for better biosecurity.

## Contribution

The study provides new prevalence data for zoonotic bacteria in the Colombian swine production chain using a One Health approach.

## Key findings

- Salmonella spp. was detected in 2.56% to 15.47% of samples, with the highest prevalence in pigs.
- E. coli O157 was found in 10% to 33.33% of samples, with the highest presence in organic material.
- Water was identified as a critical reservoir and potential primary source of bacterial contamination.

## Abstract

There are bacteria, known as zoonotic bacteria, that affect the health of animals and humans, and the environment can be a potential transmission vehicle. These bacteria can be present on pig farms and in slaughterhouses. We determined the presence of Escherichia coli and Salmonella spp. in nine Colombian farms and two slaughterhouses. Using laboratory techniques, these bacteria were detected in samples of water, feed, feces from pigs and workers, treated manure/compost, and pig carcasses. The results showed the presence of Salmonella spp. in between 2.56% and 15.47% of the samples, while E. coli O157 was present in between 10% and 33.33%. The high presence of these bacteria in the water suggests that it may be the source of contamination throughout the production chain. Although these pathogenic bacteria were not detected in workers, the zoonotic risk exists. This study highlights the need to improve biosecurity practices and farm management to reduce the risk of environmental transmission, thereby lowering risks to public, occupational, and animal health. Water treatment protocols and improved organic waste management are recommended to reduce bacterial contamination. These actions are based on the One Health approach, recognizing that animal health and environmental stability are essential for good human health.

Zoonotic pathogens in swine production can negatively impact both human and animal health, with the environment serving as a potential transmission vehicle. Therefore, this study aimed to determine the prevalence of Escherichia coli and Salmonella spp. in the Colombian swine production chain using the One Health approach. Samples were collected from nine farms and two slaughterhouses in the departments of Antioquia, Cundinamarca, Valle del Cauca, and Meta. The analyzed samples included water, feed, pig and worker feces, organic material in treatment (manure treated and compost), and pig carcasses. These samples were analyzed using standard microbiological methods and the Molecular Detection System (MDS). The results showed Salmonella spp. prevalence rates of 15.47% in pigs, 9.4% in feed, 8.47% in water, and 2.56% in organic material. For E. coli O157, prevalence rates were 25.71% in pigs, 10% in feed, 22.22% in water, and 33.33% in organic material. The high prevalence and bacterial loads in water suggest it is a critical reservoir and a potential primary source of contamination in the production chain. Although these pathogens were not detected in workers, the zoonotic risk remains. Additionally, the prevalence of haemolytic enterotoxigenic E. coli (ETEC), a major swine pathogen, was 40.1%. This study emphasizes the need to improve biosecurity and farm management practices to reduce the risk of environmental transmission, thereby minimizing public, occupational, and animal health risks. Implementing water treatment protocols and improving organic waste management are recommended to limit the spread of bacterial contamination. These actions are based on the ‘One Health’ approach, recognizing that animal health and ecosystem integrity are indivisible pillars of human health.