Rapid diagnosis of virulent Pasteurella multocida isolated from farm animals with clinical manifestation of pneumonia respiratory infection using 16S rDNA and KMT1 gene

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

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.

The immune response and protective efficacy of a potential DNA vaccine against virulent Pasteurella multocida

Background

Pasteurella multocida is the main cause of several infections of farm animals, and the immunity gained from commercial vaccines is for the short term only and needs to be routinely administered, so work on new vaccines against virulent P. multocida is crucial.

Results

In this study, the OmpH gene was amplified from ten P. multocida strains, and the PCR products were sequenced and analyzed. The results of RFLP analysis of OmpH gene digested by MspI enzyme showed that all of ten strains examined possessed one restriction site and two fragments, 350 and 650 bp. The OmpH sequence of strain No. 10 was cloned into bacterial expression vector pUCP24, and the recombinant pUCP24-OmpH was expressed in E. coli DH5α. Serum samples obtained from the ELISA test from a group of vaccinated rats indicate that the antibodies were present at high titer in immunized rats and can be tested as a vaccine candidate with a challenge.

Conclusions

In rats infected with the DNA vaccine and inactivated vaccine, a significant increase in serum antibody levels was observed. In addition, the DNA vaccine provided the vaccinated rats with partial protection; however, the protective efficacy was greater than that offered by the live attenuated vaccine. This successful recombinant vaccine is immunogenic and may potentially be used as a vaccine in the future.

Analysis of microbial diversity in apple vinegar fermentation process through 16s rDNA sequencing

Based on SPME-GC-MS analysis, it could be found that the production of acetic acid, phenethyl acetate, and isoamyl acetate gradually increased in the apple vinegar fermentation broth with the fermentation time. Consequently, in order to systematically explore the dynamic changes of microbial diversity and metabolites in the process of apple vinegar fermentation, 16S rDNA were sequenced and analyzed in this work. The present results showed that bacterial diversity was rich and exhibited a certain variation during the dynamic fermentation process of apple vinegar. Furthermore, Lactococcus and Oenococcus were the predominant bacteria in the pre-fermentation (alcoholic fermentation) of apple vinegar, while the dominant bacteria in the middle and late fermentation stages (acetic acid fermentation) were Lactococcus and Acetobacter. In addition, during the whole fermentation process of apple vinegar, Lactococcus was the most dominant bacteria, Oenococcus was the unique species in the stage of alcohol fermentation, and Acetobacter increased rapidly in the stage of acetic acid fermentation. In conclusion, our finding provided a theoretical basis for the processing technology of apple vinegar fermentation, and a theory evidence for the safety and health assessment of apple vinegar.

Isolation and molecular characterization of Mannheimia haemolytica and Pasteurella multocida associated with pneumonia of goats in Chhattisgarh

Aim:

The purpose of this study was to isolate and characterize the Mannheimia haemolytica and Pasteurella multocida from blood, nasal discharge, and lung tissue of pneumonic goats.

Materials and Methods:

A total of 14 goats were investigated for pneumonic pasteurellosis. Of 14 goats, nasal swabs and blood samples were collected from 10 clinically diseased animals. Moreover, lung tissue and heart blood samples were collected during necropsy of four goats died with pneumonia. All the samples were processed for the isolation of M. haemolytica and P. multocida in the laboratory. Bacterial isolates were identified by cultural and biochemical characters and 16S rRNA sequence analysis. All the isolates were subjected to susceptibility testing using commonly used antimicrobials. M. haemolytica isolates were characterized by PHSSA gene detection. P. multocida isolates were characterized by KMT1 gene detection and capsule typing.

Results:

On necropsy of dead goats, the pneumonia was characterized as acute fibrinous bronchopneumonia. Bacterial culture revealed the isolation of M. haemolytica (7) and P. multocida (5) of 10 clinical cases. Moreover, M. haemolytica and P. multocida were coisolated from two of the lung tissues. Furthermore, one of the other two lung tissues showed the isolation of M. haemolytica while the other showed recovery of P. multocida. Bacterial isolates were specifically identified by the 16S rRNA sequence analysis. The isolates showed reduced susceptibility to β-lactams, aminoglycosides, and fluoroquinolones. Moreover, the PHSSA and KMT1 genes were specifically detected among M. haemolytica, and P. multocida isolates, respectively. All P. multocida isolates belonged to serogroup A.

Conclusion:

The present study reported an occurrence of pneumonic pasteurellosis caused by M. haemolytica and P. multocida in a goat flock.