Fowl cholera is an infectious disease that affects both poultry and wild birds, characterized by hemorrhagic and septicemic symptoms, caused by Pasteurella multocida (P. multocida), and leading to substantial economic losses in the poultry sector. The development of genetic engineering vaccines against avian P. multocida encountered early-stage challenges due to the limited availability of effective gene editing tools. Presently, NgAgoDM-enhanced homologous recombination stands as a potent technique for achieving efficient gene knockout in avian P. multocida. Hence, this study employed NgAgoDM-enhanced homologous recombination to target and knockout hyaE (239-359aa), hyaD, hexABC, and hexD, denoted as ΔhyaE (239-359aa), ΔhyaD, ΔhexABC, and ΔhexD, respectively. Additionally, we generated a hyaD recovery strain with two point mutations, designated as mhyaD. Thus, this study systematically examined the impact of capsular synthetic gene clusters on the pathogenicity of P. multocida. Moreover, the study demonstrated the critical role of hyaD activity in the virulence of avian P. multocida. This study offers novel insights for enhancing attenuated vaccines further.

An increase in chronic, non-responsive bovine respiratory disease (BRD) infections in North American feedlot cattle is observed each fall, a time when cattle are administered multiple antimicrobial treatments for BRD. A number of factors are responsible for BRD antimicrobial treatment failure, with formation of biofilms possibly being one. It is widely accepted that biofilms play a role in chronic infections in humans and it has been hypothesized that they are the default lifestyle of most bacteria. However, research on bacterial biofilms associated with livestock is scarce and significant knowledge gaps exist in our understanding of their role in AMR of the bacterial BRD complex. The four main bacterial species of the BRD complex, Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis are able to form biofilms in vitro and there is evidence that at least H. somni retains this ability in vivo. However, there is a need to elucidate whether their biofilm-forming ability contributes to pathogenicity and antimicrobial treatment failure of BRD. Overall, a better understanding of the possible role of BRD bacterial biofilms in clinical disease and AMR could assist in the prevention and management of respiratory infections in feedlot cattle. We review and discuss the current knowledge of BRD bacteria biofilm biology, study methodologies, and their possible relationship to AMR.

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.

Pasteurellosis, a disease caused by Pasteurella multocida, is responsible for economic losses in rabbit industrial farms due to rhinitis, conjunctivitis, pneumonia, metritis, mastitis, orchitis, subcutaneous abscesses, otitis, encephalitis, and septicaemic forms. Although the occurrence of the disease is conditioned by predisposing factors that affect the rabbit immune response, the strains of P. multocida involved in the infection may have a different pathogenic ability. Therefore, typing of strains spread among the rabbits is important to assess their pathogenic potential. The aim of this study is to investigate the P. multocida strains responsible for disease in rabbit industrial farms. A total of 114 strains identified from different lesions were serotyped. Additionally, the presence of virulence-associated genes was investigated using three PCR (polymerase chain reaction) protocols. Capsular type A was prevalently found in strains from respiratory lesions while types D and F in those from metritis, mastitis, and other lesions. Different associations between some virulence-associated genes and both capsular type and lesions found in rabbits were detected. The presence of 8 virulence-associated genes seems to increase the occurrence of metritis. In addition, strains belonging to capsular type A and responsible for respiratory disorders especially, were found equipped with 10 and 11 virulence-associated genes. Nevertheless, the presence of strains responsible only for rhinitis was also detected among the latter, suggesting that the pathogenic ability of the bacteria depends on the expression rather than the presence of a gene.

This report describes a patient with Pasteurella multocida pneumonia. The patient was a man in his 70s with significant comorbid conditions, including chronic obstructive pulmonary disease (COPD), and is an example of the diverse presentations of P. multocida infections increasingly found in the literature. The novelty of this case lies in the manifestation of P. multocida pneumonia in a patient with underlying respiratory conditions and its successful management, outlining a unique clinical scenario and a tailored therapeutic approach. A 71-year-old male with a medical history of COPD, asthma, tremors, hypertension, and arthritis presented to the emergency department with progressive shortness of breath, productive cough, and chest tightness. The initial diagnosis was COPD exacerbation and left lower lobe pneumonia, for which a regimen of ceftriaxone and azithromycin was initiated. The patient\'s condition was further complicated by the persistence of symptoms. Following sputum culture analysis, P. multocida infection was identified. Consequently, the antibiotic regimen was tailored, transitioning the patient to doxycycline, which led to substantial clinical improvement, enabling discharge with a 10-day course of oral doxycycline. This case elucidates the importance of precise microbiological diagnosis in patients with complex respiratory conditions, as it guides more targeted antibiotic therapy. It highlights the need for clinical vigilance for atypical pathogens like P. multocida in patients with COPD exacerbations, especially when conventional treatment strategies yield suboptimal responses. The successful resolution of the pneumonia underscores the effectiveness of antibiotic stewardship guided by sputum culture findings.

In Italy, the use of autogenous inactivated vaccines prepared with the bacterial strains isolated from affected animals is authorized by the Ministry of Health in farms where bacterial diseases occur frequently. The autogenous vaccine performed using Pasteurella multocida is frequently used in rabbit farms, but the feedback of its application is not available. Therefore, the aim of this study is to give information about the impact on the clinical signs of a bivalent autogenous vaccine in rabbits of a genetic centre. The vaccine was prepared using two P. multocida strains belonging to serogroups A and F, equipped with virulence genes and responsible for cyclical outbreak of pasteurellosis in the farm. The vaccine was administered with a first injection, followed by another one after 15 days, then another one four months after the first injection, and then continuing with a further injection every six months to all rabbits. Clinical conditions and mortality rates were monitored for two years after the first vaccination. The improvement in clinical condition and the decrease of the mortality rate were significant especially in the first year post-vaccine. In addition, the number of animals removed due to the disease decreased greatly. Based on the finding of P. multocida strains belonging to serogroup D and serogroup A equipped with different virulence-gene patterns from those previously found, we suggest that the vaccine was unable to prevent the introduction and spreading of new strains among the rabbits.

The spread of antibiotic resistance is one of the biggest challenges of our time, making it difficult to treat bacterial diseases. Pasteurella multocida is a widespread facultative pathogenic bacterium, which causes a wide range of diseases in both mammals and birds. In the present study, antibiotic susceptibility of 155 P. multocida strains were tested using the broth microdilution method to obtain the minimum inhibitory concentration (MIC) values for 15 antibiotics. The most effective antibiotics against pasteurellosis were ceftiofur, tetracycline, doxycycline, florfenicol and tilmicosin. Of the strains, 12 proved to be multi-drug resistant (MDR). To combat antibiotic resistance, it is important to establish a pre-treatment antibiotic susceptibility profile. A well-chosen antibiotic would not only make the treatment more successful but may also slow down the spread of resistance and the evolution of MDR strains.

UNASSIGNED: Pasteurella multocida is a bacterial pathogen that causes a variety of infections across diverse animal species, with one of the most devastating associated diseases being hemorrhagic septicemia. Outbreaks of hemorrhagic septicemia in cattle and buffaloes are marked by rapid progression and high mortality. These infections have particularly harmful socio-economic impacts on small holder farmers in Africa and Asia who are heavily reliant on a small number of animals kept as a means of subsistence for milk and draft power purposes. A novel vaccine target, PmSLP-3, has been identified on the surface of hemorrhagic septicemia-associated strains of P. multocida and was previously shown to elicit robust protection in cattle against lethal challenge with a serogroup B strain.
UNASSIGNED: Here, we further investigate the protective efficacy of this surface lipoprotein, including evaluating the immunogenicity and protection upon formulation with a variety of adjuvants in both mice and cattle.
UNASSIGNED: PmSLP-3 formulated with Montanide ISA 61 elicited the highest level of serum and mucosal IgG, elicited long-lasting serum antibodies, and was fully protective against serogroup B challenge. Studies were then performed to identify the minimum number of doses required and the needed protein quantity to maintain protection. Duration studies were performed in cattle, demonstrating sustained serum IgG titres for 3 years after two doses of vaccine and full protection against lethal serogroup B challenge at 7 months after a single vaccine dose. Finally, a serogroup E challenge study was performed, demonstrating that PmSLP-3 vaccine can provide protection against challenge by the two serogroups responsible for hemorrhagic septicemia.
UNASSIGNED: Together, these data indicate that PmSLP-3 formulated with Montanide ISA 61 is an immunogenic and protective vaccine against hemorrhagic septicemia-causing P. multocida strains in cattle.

Pasteurella multocida is known to be the most commonly isolated pathogen of soft tissue infections caused by cat or dog-inflicted wounds. We present a case of a 66-year-old female who was bitten by a cat, prescribed antibiotic therapy outpatient, and developed a septic metacarpophalangeal joint despite appropriate antibiotics. A failure to improve with appropriate antibiotic therapy should raise suspicion of a source control problem and prompt surgical intervention, a principle that is highlighted in this case. Pasteurella multocida septic arthritis of the fingers manifests in less than 4% of cases, making this case a rare presentation of a septic joint, which necessitated surgical management.

Pasteurella multocida (P. multocida) is a bacterial pathogen responsible for a range of infections in humans and various animal hosts, causing significant economic losses in farming. Integrative and conjugative elements (ICEs) are important horizontal gene transfer elements, potentially enabling host bacteria to enhance adaptability by acquiring multiple functional genes. However, the understanding of ICEs in P. multocida and their impact on the transmission of this pathogen remains limited. In this study, 42 poultry-sourced P. multocida genomes obtained by high-throughput sequencing together with 393 publicly available P. multocida genomes were used to analyse the horizontal transfer of ICEs. Eighty-two ICEs were identified in P. multocida, including SXT/R391 and Tn916 subtypes, as well as three subtypes of ICEHin1056 family, with the latter being widely prevalent in P. multocida and carrying multiple resistance genes. The correlations between insertion sequences and resistant genes in ICEs were also identified, and some ICEs introduced the carbapenem gene blaOXA-2 and the bleomycin gene bleO to P. multocida. Phylogenetic and collinearity analyses of these bioinformatics found that ICEs in P. multocida were transmitted vertically and horizontally and have evolved with host specialization. These findings provide insight into the transmission and evolution mode of ICEs in P. multocida and highlight the importance of understanding these elements for controlling the spread of antibiotic resistance.