# Molecular detection of Mollicutes agents in reproductive system of cattle: a three-year study in Rio Grande do Sul, southern Brazil (2022–2024)

## TL;DR

This study found that Mollicutes bacteria, including Ureaplasma and Mycoplasma species, are present in the reproductive systems of cattle in southern Brazil, even in animals without symptoms.

## Contribution

The study provides the first detailed three-year molecular detection of Mollicutes agents in cattle reproductive systems in southern Brazil.

## Key findings

- Ureaplasma diversum was detected in 32% of samples from cattle with and without reproductive issues.
- Mollicutes were found in 23% of samples, indicating their presence in both symptomatic and asymptomatic cattle.
- Mycoplasma spp. were detected in 18% of samples, highlighting the diversity of Mollicutes in the region.

## Abstract

Rio Grande do Sul state, in southern Brazil, is one of the country’s largest cattle producers but reports few cases of genital infections caused by Mollicutes, specially Ureaplasma diversum and Mycoplasma bovis. The clinical signs associated with these bacteria can be easily confused with those caused by bovine herpesvirus (Varicellovirus bovinealpha1), Campylobacter fetus, and Tritrichomonas fetus, which complicates diagnosis. This study aimed to assess the occurrence of Mollicutes in cattle from Rio Grande do Sul between April 2022 and November 2024. Vulvo-vaginal and preputial lavage samples submitted for routine diagnosis at a Bacteriology Laboratory, were tested using PCR. Samples were first tested for U. diversum and M. bovis. Those testing negative were further examined for Mycoplasma bovigenitalium and Mycoplasma spp., and if still negative, for the Mollicutes class to detect other species. In total, 136 samples from 16 beef cattle farms in central, southern, and western regions of the state were analyzed. These included herds with reproductive disorders (n = 11) and asymptomatic animals (n = 5). U. diversum was detected in 44 samples (32%) from nine herds, both with and without reproductive issues. M. bovis was identified in one sample (1%) from a herd with reproductive problems. M. bovigenitalium was found in 11 preputial samples (9%) from three affected herds. PCR also detected Mycoplasma spp. in 25 samples (18%) and Mollicutes class in 31 samples (23%). These results confirm the presence of Mollicutes in reprodutive system in both, symptomatic and asymptomatic animals, highlighting their circulation in herds from Southern Brazil.

Mollicutes infect cattle reproductive tracts in southern Brazil.

Asymptomatic cattle can silently spread Mollicutes.

Mollicutes infections mimic other reproductive pathogens, complicating diagnosis