# No Genomic Signatures Were Found in Escherichia coli Isolates from Camels With or Without Clinical Endometritis

## TL;DR

Researchers found no specific genomic signatures in E. coli from camels with or without endometritis, suggesting other factors may be involved in disease development.

## Contribution

First comparative genomic analysis of E. coli from camel uteri with and without endometritis, revealing no genotype or virulence factor specific to the disease.

## Key findings

- No specific E. coli genotype or virulence factor was associated with endometritis in camels.
- Horizontal gene transfer via genomic islands and plasmids contributed to genetic diversity and antibiotic resistance in E. coli isolates.
- Camel uterine E. coli isolates likely originated from intestinal strains, based on phylogenetic analysis.

## Abstract

Escherichia coli is frequently isolated from camels with endometritis. In this study, we compare the virulome, genotypes, resistome, and mobilome of uterine E. coli collected from camels with and without clinical endometritis for the first time. Through genomic analysis, we found no specific E. coli genotype or virulence factor associated with endometritis. Moreover, we elucidated the contribution of horizontal gene transfer to the diversity of the gene repertoire of E. coli.

Clinical endometritis is a leading cause of infertility in she-camels. We commonly isolate E. coli from camel uteri with and without endometritis during our routine diagnosis of conception failure. From an epidemiological standpoint, it is critical to know if certain E. coli genotypes and virulence factors are specifically associated with endometritis. Thus, we aimed to compare the abundance of virulence elements and genotypes in uterine E. coli from camels with and without endometritis and understand their evolution. For this investigation, we retrieved data from the genomes of 28 E. coli isolates from humans, cats, dogs, horses, cows, and birds and 14 sequenced genomes of camel uterine E. coli isolates. We found no specific E. coli genotype or virulence factor associated with endometritis. Instead, multiple genotypes and high genomic diversity were observed. Moreover, horizontal gene transfer driven by genomic islands and plasmids contributed to the genetic diversity of the isolates, resulting in the acquisition of virulence genes, metabolic characteristics, and antibiotic resistance determinants to trimethoprim, sulfonamide, streptomycin, and tetracycline. Additionally, the phylogenetic position of the E. coli isolates from camel uteri suggests that they originated from intestinal strains. In conclusion, there was no evidence of E. coli specialization, and E. coli alone may not be able to develop endometritis, as other factors are required. Also, we elucidated the mechanism behind the diversity of the gene repertoire of E. coli isolated from camel uteri. These findings provide insight into the evolutionary origins of E. coli isolates from camel uteri.