Whole genome characterization of a multidrug-resistant hypervirulent Pasteurella multocida with a new drug-resistant plasmid

Immunoprotective efficacy of Escherichia coli-derived outer membrane vesicles displaying PlpE protein of Pasteurella multocida

Pasteurella multocida (P. multocida), a pathogenic bacterium known to induce duck cholera, stands as a significant contributor to bacterial diseases afflicting the duck industry, causing substantial annual economic losses on a global scale. In this study, the genes encoding the lipoproteins PlpE of P. multocida strain PMWSG-4 was cloned, inserted into the pBAD-ClyA vector, and the recombinant outer membrane vesicles (OMVs) fused with PlpE antigen of P. multocida was expressed by Escherichia coli (E. coli). Ducks immunized with OMV-PlpE had significantly (P < 0.001) increased production of antigen-specific antibodies. Moreover, at 28 days post-immunization, the expression of genes associated with immune response, including interleukin (IL)-2, IL-4, IL-10, and interferon (IFN)-γ in the spleen tissue of immunized ducks were significantly (P < 0.001) up-regulated compared to unimmunized ducks in the control group. And the active serum had significant bactericidal effects against the PMWSG-4 strain (P < 0.001). The protective efficacy of the vaccines was evaluated by leg muscle challenge with 20 LD50 doses of P. multocida, with the recombinant OMV-PlpE conferring 100 % protection. Histopathological examination and tissue bacterial load detection revealed that OMV-PlpE mitigated tissue damage and bacterial colonization to a statistically significant extent (P < 0.001). These findings serve as a valuable reference for the development of vaccines against P. multocida.

Pathogenicity and Genomic Characteristics Analysis of Pasteurella multocida Serotype A Isolated from Argali Hybrid Sheep

Respiratory diseases arising from co-infections involving Pasteurella multocida (P. multocida) and Mycoplasma ovipneumoniae (Mo) pose a substantial threat to the sheep industry. This study focuses on the isolation and identification of the P. multocida strain extracted from the lung tissue of an argali hybrid sheep infected with Mo. Kunming mice were used as a model to assess the pathogenicity of P. multocida. Subsequently, whole genome sequencing (WGS) of P. multocida was conducted using the Illumina NovaSeq PE150 platform. The whole genome sequencing analysis involved the construction of an evolutionary tree to depict conserved genes and the generation of a genome circle diagram. P. multocida, identified as serotype A, was named P. multocida SHZ01. Our findings reveal that P. multocida SHZ01 infection induces pathological manifestations, including hemorrhage and edema, in mice. The phylogenetic tree of conserved genes analyzing P. multocida from different countries and different host sources indicates close relatedness between the P. multocida SHZ01 strain and the P. multocida 40540 strain (A:12), originating from turkeys in Denmark. The genome of P. multocida SHZ01 comprises 2,378,508 base pairs (bp) with a GC content of 40.89%. Notably, this strain, designated P. multocida, exhibits two distinct gene islands and harbors a total of 80 effector proteins associated with the Type III Secretion System (T3SS). The P. multocida SHZ01 strain harbors 82 virulence genes and 54 resistance genes. In the P. multocida SHZ01 strain, the proteins, genes, and related GO and KEGG pathways have been annotated. Exploring the relationship between these annotations and the pathogenicity of the P. multocida SHZ01 strain would be valuable. This study holds great significance in further understanding the pathogenesis and genetic characteristics of the sheep-derived P. multocida SHZ01 strain. Additionally, it contributes to our understanding of respiratory diseases in the context of co-infection.

Concerns about the use of antimicrobials in swine herds and alternative trends

Pig productivity in Brazil has advanced a lot in recent decades. Specialized breeds are more vulnerable to pathogens, which has boosted the use of antimicrobials by farmers. The selective pressure generated favors the emergence of resistant bacteria, which compromises the effectiveness of this treatment and limits therapeutic options. In addition to increasing costs and mortality rates in the production system, public awareness of this issue has increased. The authorities have imposed restrictive measures to control the use of antimicrobials and have banned their use as growth promoters. This literature review highlights biosecurity and animal welfare to prevent pig diseases. Hence, we describe alternatives to the use of antimicrobials in pig production for the selection of effective non-antibiotic feed additives that help maintain good health and help the pig resist disease when infection occurs.

Pasteurella multocida strains of a novel capsular serotype and lethal to Marmota himalayana on Qinghai-Tibet plateau in China

Pasteurella multocida is a zoonotic pathogen causing serious diseases in humans and animals. Here, we report P. multocida from wildlife on China's Qinghai-Tibet plateau with a novel capsular serotype, forming a single branch on the core-genome phylogenetic tree: four strains isolated from dead Himalayan marmot (Marmota himalayana) and one genome assembled from metagenomic sequencing of a dead Woolly hare (Lepus oiostolus). Four of the strains were identified as subspecies multocida and one was septica. The mouse model showed that the challenge strain killed mice within 24 h at an infectious dose of less than 300 bacteria. The short disease course is comparable to septicemic plague: the host has died before more severe pathological changes could take place. Though pathological changes were relatively mild, cytokine storm was obvious with a significant rise of IL-12p70, IL-6, TNF-αand IL-10 (P < 0.05). Our findings suggested P. multocida is a lethal pathogen for wildlife on Qinghai-Tibet plateau, in addition to Yersinia pestis. Individuals residing within the M. himalayana plague focus are at risk for P. multocida infection, and public health warnings are necessitated.