Genomic and Transcriptomic Analysis of Bovine Pasteurella multocida Serogroup A Strain Reveals Insights Into Virulence Attenuation

Abstract

Pasteurella multocida is one of the primary pathogens of bovine respiratory disease (BRD), and causes huge losses in the cattle industry. The Pm3 strain was a natural isolate, which is a strong form of pathogen and is sensitive to fluoroquinolones antibiotics. A high fluoroquinolone resistant strain, Pm64 (MIC = 64 μg/mL), was formed after continuous induction with subinhibitory concentration (1/2 MIC) of enrofloxacin, with the enhanced growth characteristics and large attenuation of pathogenicity in mice. This study reports the whole genome sequence and the transcription profile by RNA-Seq of strain Pm3/Pm64. The results showed an ineffective difference between the two strains at the genome level. However, 32 genes could be recognized in the gene islands (GIs) of Pm64, in which 24 genes were added and 8 genes were lost. Those genes are involved in DNA binding, trehalose metabolism, material transportation, capsule synthesis, prophage, amino acid metabolism, and other functions. In Pm3 strain, 558 up-regulated and 568 down-regulated genes were found compared to Pm64 strain, from which 20 virulence factor-related differentially expressed genes (DEGs) were screened. Mainly differentially transcribed genes were associated with capsular polysaccharide (CPS), lipopolysaccharide (LPS), lipooligosaccharide (LOS). Iron utilization, and biofilm composition. We speculated that the main mechanism of virulence attenuation after the formation of resistance of Pm64 comes from the change of the expression profile of these genes. This report elucidated the toxicity targets of P. multocida serogroup A which provide fundamental information toward the understanding of the pathogenic mechanism and to decreasing antimicrobial drugs resistance.

Transcriptomic Changes and satP Gene Function Analysis in Pasteurella multocida with Different Levels of Resistance to Enrofloxacin

“…One unanticipated finding was that the virulence of the satP gene deletion strain was several times lower than that of the wild-type strain, and we found that the treatment rate of the mice infected with ∆PmS was higher. This finding broadly supports the work of other studies in this area which links tolerance with virulence [47]. However, there are also some reports contrary to this study.…”

Integration of Non-Coding RNA and mRNA Profiles Reveals the Mechanisms of Rumen Development Induced by Different Types of Diet in Calves

“…First, Qubit was used for preliminary quantification, and the library was diluted to 1 ng/µL. Then, the Agilent 2100 BioAnalyzer was used to detect the insert size of the library [26]. The insert size was about 250-300 bp, in line with the expected Insert size.…”

Role of biofilms in antimicrobial resistance of the bacterial bovine respiratory disease complex

“…CP00332), the tad locus contained the 14 intact genes that this locus typically harbors, i.e., flp1-flp2-tadV-rcpCAB-tadZABCDEFG (42). However, the specific involvement of tad genes in biofilm formation in P. multocida requires further evaluation as they are not conserved across all strains (38,39,(42)(43)(44)(45). The csrA gene is involved in glycogen synthesis and as a result, it plays a role in biofilm formation (7).…”

“…The csrA gene is involved in glycogen synthesis and as a result, it plays a role in biofilm formation (7). Other P. multocida genes with possible direct or indirect biofilm regulation roles include xylB, sgbU, hexD, aspA, comE, qseC, and pmorf0222 (7,43,(46)(47)(48). Of special interest is the qseC gene and its role in QS modulating the transcription of thousands of genes.…”