Prevalence and Molecular Characterization of Mycoplasma Species, Pasteurella multocida, and Staphylococcus aureus Isolated from Calves with Respiratory Manifestations.

Youserya M Hashem,Ayman M Megahed,Ahmad El-Askary,Mohammed Nooruzzaman,Eman E Abdeen,Ahmed Abdeen,Enas A Soliman,Khadiga A Ismail,Gamal Wareth,Hanaa M Abdelkhalek,Walid S Mousa

doi:10.3390/ani12030312

Abstract

Simple SummaryRespiratory infection is one of the most common problems facing the livestock industry in Egypt, and results in substantial economic losses. Several bacterial pathogens are implicated in respiratory infections in young calves. In our study, Mycoplasma bovis, Mycoplasma bovigenitalium, Pasteurella multocida, and Staphylococcus aureus were the most common bacterial pathogens isolated from calves suffering from respiratory manifestations in Menoufiya Governorate, Egypt. However, the results revealed a low prevalence of these pathogens compared to other studies carried out in Egypt. This may be due to the low number of samples or application of vaccination programs in the study area. Mixed infection is the main perceived criteria in this study. The genetic characterization of these pathogens revealed the high identity and similarities within several global and local linages, proposing the probability of disseminating these bacterial pathogens through several routes during animal contact and movements and animal trading between different geographic locations around the world.Bovine respiratory disease (BRD) is a complex syndrome associated with high mortality in young calves and causes severe economic losses in the cattle industry worldwide. The current study investigated the prevalence and molecular characterization of common bacterial pathogens associated with respiratory symptoms in young calves from Sadat City, one of the largest industrial cities in Menoufiya Governorate, Egypt. In between December 2020 and March 2021, 200 mixed-breed young calves of 6–12 months were examined clinically. Of them, sixty (30%) calves showed signs of respiratory manifestations, such as coughing, serous to mucopurulent nasal discharges, fever, and abnormal lung sound. Deep nasal (Nasopharyngeal) swabs were collected from the affected calves for bacteriological investigation. Phenotypic characterization and identification revealed Mycoplasma bovis, Mycoplasma bovigenitalium, Pasteurella multocida, and Staphylococcus aureus in 8.33%, 5%, 5%, and 5% of the tested samples, respectively. The PCR technique using species-specific primer sets successfully amplified the target bacterial DNA in all culture-positive samples, confirming the identity of the isolated bacterial species. Partial gene sequencing of 16S rRNA gene of M. bovigenitalium, P. multocida, and S. aureus, and mb-mp 81 gene of M. bovis revealed high nucleotide similarity and genetic relationship with respective bacterial species reported from Egypt and around the world, suggesting transmission of these bacterial species between animal host species and localities. Our study highlights the four important bacterial strains associated with respiratory disorders in calves and suggests the possible spread of these bacterial pathogens across animal species and different geographic locations. Further studies using WGS and a large number of isolates are required to investigate the realistic lineage of Egyptian isolates and globally.

Highlights

Bovine respiratory disease (BRD) is one of the major problems in the livestock industry [1,2]
As respiratory infections incur severe economic losses and fatal complications in young calves due to pneumonia, this study aimed to determine the prevalence, molecular characterization, and sequencing analysis of the most common bacterial pathogens associated with the respiratory manifestations in young calves in Sadat City, one of the most important cities targeted for reclamation and animal production sectors by the government in Egypt
Prevalence of M. bovis, M. bovigenitalium, P. multocida, and S. aureus Recovered from Calves with Respiratory Signs

Summary

Introduction

Bovine respiratory disease (BRD) is one of the major problems in the livestock industry [1,2]. Many pathogenic bacteria, such as Pasteurella multocida, Mannheimia haemolytica, Mycoplasma bovis, and other opportunistic bacteria, such as Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Corynebacteria, Haemophilus, Escherichia coli, and Klebsiella pneumonia are involved in respiratory syndromes in calves [2,7,8]. Most of these bacterial species are commensal in the upper respiratory tract of cattle. Stresses or viral infections lower the immune responses of the animal and pave the way for opportunistic bacteria to colonize the respiratory system, be inhaled into the lungs, and lead to bronchopneumonia [9]

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