Pasteurella Multocida Research Articles

Porcine reproductive and neonatal infections: Importance and threats of bacterial virophoria

The provisions of the doctrine of transfer the epizootic process of dangerous viral infections to the enzootic process and their rooting in pig production through the integration of their pathogen into the pig microbiome in the form of comorbid viral and bacterial infections are substantiated. The aim of the study is to systematize the bacterial virophoria in the epizootology of porcine reproductive and neonatal infections (PRNI) as a component of the enzootic cycle of emergent infections in the pig industry of Ukraine. Classical swine fever (CSF) virus: attenuated strain ‘IECVM 03’; Aujeszky’s disease (AD) virus: epizootic strains of Ukrainian origin of AD virus ‘18v UNDIEV’; Teschen disease (TD) virus: epizootic strain ‘Bucha’. Epizootic strains: pasteurella bacteria, streptococcus, lacto- and bifidobacteria. According to the results of the study, it was found that the rotating magnetic field of the right direction promoted the adsorption of the CSF virus on pasteurella cells. The Aujeszky’s disease virus was adsorbed on the bacteria Salmonella choleraesuis No. 34, Bacterium bifidum and Lactobacillus casei with an efficiency of 15–45% in the pH range of 8.5–9.5, at neutral pH (7.4) no more than 1.5% of the virus was adsorbed, and at acidic pH (3.0) the AD virus was not adsorbed et all. On bacteria Pasteurella multocida No. 7, AD virus was adsorbed in the pH range of 8.5–9.5 with an efficiency of no more than 1.5%; at neutral pH (7.4), up to 50% of the virus was adsorbed, and at acidic pH (3.0), no more than 1.5% of AD virus was adsorbed. The interaction of TD virus with bifidobacteria inhibited viral reproduction in the body of infected polecats, but preserved the reproductive activity of teschovirus in the presence of streptococci. The rooting of dangerous viral infections (AD and TD, circovirus and parvovirus infections, reproductive and respiratory syndrome, and endemic porcine diarrhea) in pig production has always been accompanied by the ‘engraftment’ of their pathogens in the microbiome of pig production facilities in the form of comorbid (i. e. clinically manifested) and/or associated infections (i. e. similar to the group of Minimal Residual Human Diseases — Maladie Résiduelle Minimale, MRD). A key role in the establishment of these diseases and the formation of their stationary centers in pig production is played by the virophoria of bacteria synergistic with their pathogens, in particular as part of the etiologic microflora of reproductive and neonatal infections in pigs

INFECTION AND SYSTEMIC COMPLICATIONS BY PASTEURELLA SPP. IN A RABBIT: A CASE STUDY

The coexistence of rabbits in parks and public recreation areas is a common scene; however, this interaction is not without risks as rabbits can be carriers of bacterial infectious diseases, posing a potential risk to public health. The Pasteurella genus, including Pasteurella multocida, plays a central role in developing bacterial infections that affect rabbits and other lagomorphs. Infection by this genus typically manifests with respiratory symptoms such as nasal discharge and sneezing, but the concern goes beyond that due to its zoonotic nature. These pathogens have the ability to be transmitted to humans, usually through bites, scratches, or direct contact, emphasizing the importance of careful management and preventive measures. Diagnosis in rabbits involves a comprehensive analysis, including clinical signs, medical history, laboratory tests, and specific tests. Symptoms such as nasal discharge, watery eyes, abscesses, and lethargy are common. Medical history and physical examination are crucial, along with the culture of samples and, when possible, serological tests. This case report describes the occurrence of pasteurellosis in a female rabbit treated at CRAS - Pró Arara "Raul de Barros Winter" in Araras, São Paulo, Brazil, highlighting the importance of surveillance, proper management, and awareness to mitigate public health risks associated with the coexistence of rabbits and humans in public recreation areas.

C5 (Clinical Case) Coccobacillary Meningitis and Septic Embolic Infarcts in an Ex-Preterm Infant: An Unexpected Pathogen

Abstract Introduction/Background Pasteurella multocida causes life-threatening zoonotic invasive infections in immunocompromised individuals and those at extremes of age (neonates and elderly). Bacteremia, meningitis, and endocarditis are serious complications that are associated with up to 25-30% mortality. Case Description A 7-week-old ex-34-week preterm female infant presented with a one-day history of fever, irritability, and poor feeding without exposure to sick contacts. Household contacts included a constantly drooling Shi Tzu dog. Examination revealed an irritable, febrile infant with a bulging fontanelle and scant purulent eye discharge. No focal neurological deficits, skin rashes or murmurs were appreciated. Empiric antibiotics were initiated following a full work-up for sepsis. Cerebrospinal fluid (CSF) analysis showed neutrophilic pleocytosis with 7608 x106L nucleated cells (95% neutrophils), protein 7360 mg/L, glucose <0.2 mmol/L and gram-negative coccobacilli. Blood and CSF cultures grew Pasteurella multocida, prompting a switch to crystalline penicillin. An echogenic mitral valvular mass was identified in the absence of underlying cardiac defects. Head imaging confirmed ventriculitis with multiple small infarcts. No sequelae of abscess, hydrocephalus or hearing loss were demonstrated after the completion of 6 weeks of penicillin therapy. Discussion Haemophilus influenzae, serotype b, is the typical cause of coccobacillary meningitis in a 7-week-old infant. In addition to non-b serotypes, non-typeable species which cause conjunctivitis may also cause invasive disease in young infants. The resultant growth of P. multocida from cultures was, therefore, unexpected, particularly given there were no preceding animal bites or scratches. In vulnerable hosts, this pathogen can be transmitted across skin or mucous membranes after close animal contact, such as licking and sniffing. The constant drooling and spraying of saliva from the pet dog, a flat-faced breed known to have stenotic nares and chronic nasal secretions, likely provided an opportunity for mucosal contamination. This infant’s young age, prematurity, and exposure to a flat-faced dog placed her at high risk for Pasteurellosis, which manifested as complicated meningitis and endocarditis. Conclusion Pasteurella infections most often arise as local infections following an animal bite or scratch, are rare but important causes of life-threatening severe coccobacillary invasive infection, even without preceding trauma, in young infants. Families of at-risk individuals who own pets should have adequate education about zoonotic infections that address risk factors, including animal breed and behaviour, presenting features and preventive strategies to reduce the potential for serious morbidity and even mortality.

Optimizing tylosin dosage for co-infection of Actinobacillus pleuropneumoniae and Pasteurella multocida in pigs using pharmacokinetic/pharmacodynamic modeling.

Formulating a therapeutic strategy that can effectively combat concurrent infections of Actinobacillus pleuropneumoniae (A. pleuropneumoniae) and Pasteurella multocida (P. multocida) can be challenging. This study aimed to 1) establish minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time kill curve, and post-antibiotic effect (PAE) of tylosin against A. pleuropneumoniae and P. multocida pig isolates and employ the MIC data for the development of epidemiological cutoff (ECOFF) values; 2) estimate the pharmacokinetics (PKs) of tylosin following its intramuscular (IM) administration (20mg/kg) in healthy and infected pigs; and 3) establish a PK-pharmacodynamic (PD) integrated model and predict optimal dosing regimens and PK/PD cutoff values for tylosin in healthy and infected pigs. The MIC of tylosin against both 89 and 363 isolates of A. pleuropneumoniae and P. multocida strains spread widely, ranging from 1 to 256μg/mL and from 0.5 to 128μg/mL, respectively. According to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) ECOFFinder analysis ECOFF value (≤64µg/mL), 97.75% (87 strains) of the A. pleuropnumoniae isolates were wild-type, whereas with the same ECOFF value (≤64µg/mL), 99.72% (363 strains) of the P. multicoda isolates were considered wild-type to tylosin. Area under the concentration time curve (AUC), T1/2, and Cmax values were significantly greater in healthy pigs than those in infected pigs (13.33h × μg/mL, 1.99h, and 5.79μg/mL vs. 10.46h × μg/mL, 1.83h, and 3.59μg/mL, respectively) (p < 0.05). In healthy pigs, AUC24h/MIC values for the bacteriostatic activity were 0.98 and 1.10h; for the bactericidal activity, AUC24h/MIC values were 1.97 and 1.99h for A. pleuropneumoniae and P. multocida, respectively. In infected pigs, AUC24h/MIC values for the bacteriostatic activity were 1.03 and 1.12h; for bactericidal activity, AUC24h/MIC values were 2.54 and 2.36h for A. pleuropneumoniae and P. multocida, respectively. Monte Carlo simulation lead to a 2μg/mL calculated PK/PD cutoff. Managing co-infections can present challenges, as it often demands the administration of multiple antibiotics to address diverse pathogens. However, using tylosin, which effectively targets both A. pleuropneumoniae and P. multocida in pigs, may enhance the control of bacterial burden. By employing an optimized dosage of 11.94-15.37mg/kg and 25.17-27.79mg/kg of tylosin can result in achieving bacteriostatic and bactericidal effects in 90% of co-infected pigs.

Differentiating airway inflammation in calves based on cluster analysis of bronchoalveolar lavage fluid cytology.

Nonbronchoscopic bronchoalveolar lavage (nBAL) is routinely performed in calves, and airway cytology has great potential in airway disease diagnostics. A good reference framework for nBAL cytology is lacking. To distinguish different cytological profiles in nBAL from grouped housed calves using cluster analysis, and characterize these profiles on individual and herd levels. Three hundred thirty-eight group-housed calves from 60 herds (mainly dairy and beef ). Cross-sectional study. Differential counts of white blood cells were determined on nBAL fluid, followed by differentiation of cytological profiles by K-means-based cluster analysis. These profiles were characterized by reference values, decision tree analysis, and associations with clinical, ultrasonographic, bacteriological, and cytological features. A normal (55.9%), a neutrophilic (41.1%), and an eosinophilic profile (3.0%) were identified. The normal profile was characterized by reference values of 2.3% to 47.4% neutrophils, 35.1% to 95.1% macrophages, 0.4 to 22.9% lymphocytes, and 0.0% to 0.9% eosinophils. The neutrophilic profile was characterized by ≥44.5% neutrophils, <1.6% eosinophils, and <11.5% lymphocytes. This profile was associated with the isolation of Pasteurella multocida, the presence of neutrophils with toxic granulation, and the presence of phagocytosed bacteria in neutrophils. The eosinophilic profile was characterized by eosinophils ≥1.6% (neutrophilia present) or ≥2.4% (neutrophilia absent), and associated with the presence of mast cells. On herd level, the neutrophilic and eosinophilic profiles were present in 85.0% and 15.0% of the herds, respectively. This study provides a first step in the development of cytological guidelines, aiding the assessment of airway health and inflammation in calves through nBAL fluid cytology.

Efficiency of NHEJ-CRISPR/Cas9 and Cre-LoxP Engineered Recombinant Turkey Herpesvirus Expressing Pasteurella multocida OmpH Protein for Fowl Cholera Prevention in Ducks.

Fowl cholera is caused by the bacterium Pasteurella multocida, a highly transmissible avian ailment with significant global implications, leading to substantial economic repercussions. The control of fowl cholera outbreaks primarily relies on vaccination using traditional vaccines that are still in use today despite their many limitations. In this research, we describe the development of a genetically engineered herpesvirus of turkeys (HVT) that carries the OmpH gene from P. multocida integrated into UL 45/46 intergenic region using CRISPR/Cas9-NHEJ and Cre-Lox system editing. The integration and expression of the foreign cassettes were confirmed using polymerase chain reaction (PCR), indirect immunofluorescence assays, and Western blot assays. The novel recombinant virus (rHVT-OmpH) demonstrated stable integration of the OmpH gene even after 15 consecutive in vitro passages, along with similar in vitro growth kinetics as the parent HVT virus. The protective efficacy of the rHVT-OmpH vaccine was evaluated in vaccinated ducks by examining the levels of P. multocida OmpH-specific antibodies in serum samples using ELISA. Groups of ducks that received the rHVT-OmpH vaccine or the rOmpH protein with Montanide™ (SEPPIC, Paris, France) adjuvant exhibited high levels of antibodies, in contrast to the negative control groups that received the parental HVT or PBS. The recombinant rHVT-OmpH vaccine also provided complete protection against exposure to virulent P. multocida X-73 seven days post-vaccination. This outcome not only demonstrates that the HVT vector possesses many characteristics of an ideal recombinant viral vaccine vector for protecting non-chicken hosts, such as ducks, but also represents significant research progress in identifying a modern, effective vaccine candidate for combatting ancient infectious diseases.

Characterization of the plasmids harbouring the florfenicol resistance gene floR in Glaesserella parasuis and Actinobacillus indolicus

The aim of this study was to characterize the floR-carrying plasmids originating from Glaesserella parasuis and Actinobacillus indolicus isolated from pigs with respiratory disease in China. A total of 125 G. parasuis and 28 A. indolicus strains collected between 2009 and 2022 were screened for florfenicol resistance. Characterization of floR-positive isolates and plasmids were determined by antimicrobial susceptibility testing, serotyping, multilocus sequence typing (MLST), conjugation and transformation assays, whole-genome sequencing (WGS), and phylogenetic analysis. One A. indolicus and six G. parasuis were identified as positive for floR. The six G. parasuis were assigned to four different serovars, including serovars 6, 7, 9, and unknown. In addition to strain XP11, six floR genes were located on plasmids. The six floR-bearing plasmids could be transformed into Pasteurella multocida and divided into two different types, including ∼5000 bp and ∼6000 bp plasmids. The ∼5000 bp plasmids consisting of rep, lysR, mobB, and floR genes, exhibited high similarity among Pasteurellaceae bacteria. Furthermore, the ∼6000 bp plasmids, consisting of rep, lysR, mobC, mobA/L, and floR genes, showed high similarity between G. parasuis and Actinobacillus Spp. Notably, WGS results showed that the floR modules of the two types of plasmids could be transferred and integrated into the diverse Pasteurellaceae- origined plasmids. This study firstly reported the characterization of floR-carrying plasmids from A. indolicus and a non-virulent serovar of G. parasuis in pigs in China and elucidated the transmission mechanism of the floR resistance gene among the Pasteurellaceae family.

Genomic characterization and comparative genomic analysis of HS-associated Pasteurella multocida serotype B:2 strains from Pakistan

BackgroundHaemorrhagic septicaemia (HS) is a highly fatal and predominant disease in livestock, particularly cattle and buffalo in the tropical regions of the world. Pasteurella multocida (P. multocida), serotypes B:2 and E:2, are reported to be the main causes of HS wherein serotype B:2 is more common in Asian countries including Pakistan and costs heavy financial losses every year. As yet, very little molecular and genomic information related to the HS-associated serotypes of P. multocida isolated from Pakistan is available. Therefore, this study aimed to explore the characteristics of novel bovine isolates of P. multocida serotype B:2 at the genomic level and perform comparative genomic analysis of various P. multocida strains from Pakistan to better understand the genetic basis of pathogenesis and virulence.ResultsTo understand the genomic variability and pathogenomics, we characterized three HS-associated P. multocida serotype B:2 strains isolated from the Faisalabad (PM1), Peshawar (PM2) and Okara (PM3) districts of Punjab, Pakistan. Together with the other nine publicly available Pakistani-origin P. multocida strains and a reference strain Pm70, a comparative genomic analysis was performed. The sequenced strains were characterized as serotype B and belong to ST-122. The strains contain no plasmids; however, each strain contains at least two complete prophages. The pan-genome analysis revealed a higher number of core genes indicating a close resemblance to the studied genomes and very few genes (1%) of the core genome serve as a part of virulence, disease, and defense mechanisms. We further identified that studied P. multocida B:2 strains harbor common antibiotic resistance genes, specifically PBP3 and EF-Tu. Remarkably, the distribution of virulence factors revealed that OmpH and plpE were not present in any P. multocida B:2 strains while the presence of these antigens was reported uniformly in all serotypes of P. multocida.ConclusionThis study's findings indicate the absence of OmpH and PlpE in the analyzed P. multocida B:2 strains, which are known surface antigens and provide protective immunity against P. multocida infection. The availability of additional genomic data on P. multocida B:2 strains from Pakistan will facilitate the development of localized therapeutic agents and rapid diagnostic tools specifically targeting HS-associated P. multocida B:2 strains.

Kinetics of humoral response to Pasteurella multocida in buffaloes against combined foot-and-mouth+haemorrhagic septicaemia vaccine

The present study reports kinetics of anti-P. multocida antibody (Ab) response at monthly intervals in Murrah buffaloes of different age groups vaccinated against combined Foot-and-mouth disease+haemorrhagic septicaemia (FMD+HS) vaccine. A total of 60 Murrah buffaloes of three age groups having 20 animals each: calves, heifers and adults were used to monitor anti-P. multocida Ab response at monthly intervals using single dilution indirect ELISA. The percentage of adult buffaloes protected were found to be the highest during all the six months post-vaccination followed by heifers and calves. The protective mean Ab titres were maintained up to six months post-vaccination for heifers and adults but not for calves. The F value (the ratio of two mean squares) for pre- and all the six month(s) post-vaccination and all the three age groups was significantly higher. Pearson Chi square value for pre-vaccination and all the six months except three months post-vaccination was significantly higher. Pearson correlation value was significantly higher with positive linear relationship. The data in the present study indicated that the combined FMD+HS vaccine was found to be effective in buffaloes of all age groups at government organised farm and could be an ideal approach in field conditions under Livestock Health Disease Control Program run by the Government of India.

Laboratory Evaluation of Transtracheal Wash (TTW) in Buffaloes Affected with Lower Respiratory Tract Infections

Background- Evaluation of transtracheal wash (TTW) has been proved beneficial in the diagnosis and understanding the pathology of lower respiratory tract infection in species like equines and dogs. However, its diagnostic potential in buffaloes has not been explored much. This study elucidated the cytological and microbiological features of TTW in buffaloes. Methods- TTW was collected from 36 buffaloes (26 diseased and 10 healthy control) after adequately restraining and using baby feeding tube after giving a small stab incision at ventral neck region. After collection, TTW were subjected to cytological studies following staining with Leishman stain. TTW was also sent aseptically to laboratory for bacteriological culture. Results- The lower respiratory tract affections like aspiration pneumonia, suppurative pneumonia, fibrinopurulent pneumonia, chronic pneumonia and tuberculous pneumonia were diagnosed based on cytology of TTW in correlation with history and comprehensive clinical examination. The mean cell number (cells/HPF) in TTW of diseased buffaloes were significantly higher than control groups. In control groups, the predominant cells were alveolar macrophages followed by neutrophils, epithelial cells, lymphocytes and other cells which includes mast cells, fibroblasts and unidentified nucleated cells. Neutrophils were the predominant cells followed by macrophages in TTW of buffaloes diagnosed with suppurative, fibrinopurulent and aspiration pneumonia, whereas, alveolar macrophage were predominant in TTW of chronic pneumonia and tuberculous pneumonia affected animals. Four out of ten TTW samples from healthy animals were evidenced bacterial growth in which Staphylococcus spp. was the predominantly isolated bacteria. TTW samples from 20 out of 26 diseased buffaloes were found positive for bacterial culture from which a total of 30 bacterial isolates were obtained which include Staphylococcus aureus, Klebsiella pneumonia, Pasteurella multocida, Streptococcus spp., E. coli and Bacillus spp. Thus, TTW provides vital information about the ongoing pathogenesis in respiratory tract infection. It is suggested that, cytological and bacteriological culture of TTW samples should be carried out during the diagnosis and therapeutic intervention of respiratory tract infection in buffaloes.

RACK1 mediates NLRP3 inflammasome activation during Pasteurella multocida infection

Pasteurella multocida is a gram-negative bacterium that causes serious diseases in a wide range of animal species. Inflammasomes are intracellular multimolecular protein complexes that play a critical role in host defence against microbial infection. Our previous study showed that bovine P. multocida type A (PmCQ2) infection induces NLRP3 inflammasome activation. However, the exact mechanism underlying PmCQ2-induced NLRP3 inflammasome activation is not clear. Here, we show that NLRP3 inflammasome activation is positively regulated by a scaffold protein called receptor for activated C kinase 1 (RACK1). This study shows that RACK1 expression was downregulated by PmCQ2 infection in primary mouse peritoneal macrophages and mouse tissues, and overexpression of RACK1 prevented PmCQ2-induced cell death and reduced the numbers of adherent and invasive PmCQ2, indicating a modulatory role of RACK1 in the cell death that is induced by P. multocida infection. Next, RACK1 knockdown by siRNA significantly attenuated PmCQ2-induced NLRP3 inflammasome activation, which was accompanied by a reduction in the protein expression of interleukin (IL)-1β, pro-IL-1β, caspase-1 and NLRP3 as well as the formation of ASC specks, while RACK1 overexpression by pcDNA3.1-RACK1 plasmid transfection significantly promoted PmCQ2-induced NLRP3 inflammasome activation; these results showed that RACK1 is essential for NLRP3 inflammasome activation. Furthermore, RACK1 knockdown decreased PmCQ2-induced NF-κB activation, but RACK1 overexpression had the opposite effect. In addition, the immunofluorescence staining and immunoprecipitation results showed that RACK1 colocalized with NLRP3 and that NEK7 and interacted with these proteins. However, inhibition of potassium efflux significantly attenuated the RACK1-NLRP3-NEK7 interaction. Our study demonstrated that RACK1 plays an important role in promoting NLRP3 inflammasome activation by regulating NF-κB and promoting NLRP3 inflammasome assembly.

Pasteurella multocida causes liver injury in ducks by mediating inflammatory, apoptotic and autophagic pathways

Pasteurella multocida.(PM) infection is a major cause of avian cholera, but the pathogenesis of the disease is unknown. The purpose of this study was to further understand the host response to infection by using a duck model of PM, 20 female ducks were divided into two groups (n = 10). One group was infected with PM, while the other served as an uninfected control group. The ducks were observed after infection and samples were collected for testing. In this study, we report the mechanism of PM-induced inflammation to further mediate apoptosis and autophagic signaling pathways in liver cells. Our results demonstrated that PM infection initially induces hemorrhagic and necrotic lesions in the liver tissue of duck, promoting inflammasome assembly and release, triggering inflammation. The TLR4/NF-κB axis activated and interacted with multiple inflammation-related proteins, including TNF-α and IL-1β, which affected apoptosis and autophagy. Tumor necrosis factor induced hepatocyte apoptosis was implicated in a wide range of liver diseases; the release of TNF-α and activation with NF-κB further incite apoptotic pathways,such as Bax/BCL2/caspase to promote apoptotic genes APAF1, Bax, Caspase3, BCL-2, p53, and Cytc expression. Finally, PM-induced autophagy suppressed liver injury by promoting the Beclin-1, LC3B, p62, and mTOR. Thus, liver injury caused by PM via promoting autophagy was induced. In conclusion, we analyzed the liver injury of ducks infected with PM, and confirmed that inflammation appeared in the liver; this was followed by the intricate interplay between inflammation, apoptosis, and autophagy signaling pathways. The observed results provided a reference basis for studying pathogenic mechanisms of PM-host interactions.

IFN-γ promotes PANoptosis in Pasteurella multocida toxin-induced pneumonia in mice

Interferon-γ (IFN-γ) is a pleiotropic cytokine that regulates diverse biological functions, including modulation of inflammatory response and innate and adaptive immunity. In our study, we found that IFN-γ plays an important role in the regulation of Pasteurella multocida toxin-associated pneumonia. In work described here, we demonstrated that rPMT induced a lethal pneumonia in WT mice and the severity of the pneumonia was substantially alleviated in IFN-γ-deficient mice, IFN-γ deficiency significantly elevated the survival rate and reduced the pathological lesions of the lungs after rPMT challenged. Notably, IFN-γ deficiency significantly decreased myeloperoxidase (MPO) expression abundance in the lung tissue, and the MPO was mainly expressed in the lung tissue injury region of WT mice. More importantly, IFN-γ deficiency impaired the activation of PANoptosis specific markers, including the caspase 3, GSDMD, and MLKL, and reduced the expression of IL-1β. Cumulatively, this study demonstrates that IFN-γ promotes PANoptosis in PMT induced pneumonia in mice, providing a basis for studying the pathogenic mechanism of PMT.

The enigmatical manipulators in the capsule synthesis of Pasteurella multocida: Iron acquisition proteins

Aim: Spontaneous capsular loss or capsular changes in Pasteurella multocida can result from repeated laboratory passages, positive or negative regulatory genes, or an unknown gene. This study, it was aimed to compare the properties of phenotypic, genotypic, and biotypic of each non-typical, and typical Pasteu-rella multocida strain, to determine the dominant genes on capsule synthesis. Materials and Methods: Fifty-six strains, which capsular type was determined, and thirty -six, which capsular type was not determined, were used in this study. Multiple linear regression analysis was used based on the presence of dominant genes (serogroup, serotype, toxin, adhesin, iron acquisition, and protectin) in the isolates. Results: When colony morphologies of strains were evaluated of these strains by culture methods, mucoid colony formation was commonly detected in typical strains (87.5%), in contrast to non-typical strains (27.7%). In typical strains, the highest percentages of ptfA, ompA, and tadD genes were 78.57%, 75%, and 69.64%, respectively. In non-typical strains, the highest rates of ompA, ptfA, and tadD genes were 61.1%, 52.78%, and 52.78%, respectively. According to multiple linear regression analysis results, the together hgbA with hgbB genes caused the increase of capsule synthesis in these strains. The presence of the ompA gene in these strains was secondly a induction on these strains. Other genes were not effective in capsule synthesis in these strains. Conclusion: It was determined that the most significant effect in the forming of non-typical P. multocida strains was related to not enough HgbA and HgbB genes. It was supposed that P. multocida may not be heavily encapsulated under iron-restricted conditions. Consequently, P. multocida may change its capsule or lose its capsule related to iron acquisition proteins.

Effects of &lt;i&gt;peste des petit ruminants&lt;/i&gt; N/75/1 vaccine on nasal bacterial flora and clinical indices in Red Sokoto goats

Peste des petit ruminants virus (PPRv) and Mannheimia haemolytica have been commonly implicated in naturally occurring pneumonia in sub-Saharan Africa and account for huge economic losses as they are associated with high morbidity and mortality. The Nigerian 75/1 PPR vaccine has been proven to be efficacious in the control of PPR. However, there is a paucity of information on the ability of this live attenuated vaccine to modulate bacteria of the nasal flora to control or confer protection against secondary bacterial infection induced especially by M. haemolytica. Nasal swabs and blood samples were collected for bacterial count and serology respectively. This study describes the effect of the N/75/1 PPR vaccine on the nasal bacteria flora and clinical indices of Red Sokoto goats. Ten (10) Red Sokoto goats were divided into two groups of five animals each. In one group, 1ml of PPR vaccine (2.5 TCID50) was administered subcutaneously while the other group served as control and 1ml of normal saline was administered subcutaneously. The results showed that for the PPR vaccinated group, although there was a significant decrease (p≤0.05) in nasal bacteria counts for Mannheimia haemolytica, Pasteurella multocida and Escherichia coli compared to the control group it was not sufficient to clear out these potentially pathogenic bacteria from the nasal flora. Also, in the PPR-vaccinated group, the only clinical symptom observed was a mild transient and self-limiting hyperthermia at about 2 weeks post-vaccination which may be attributed to the initiation and enhancement of immune responses. Hence, it can be deduced that the PPR vaccine may moderately inhibit the colonization of certain pathogenic bacteria of the nasal microbial flora but however, it is incapable of conferring total immunity against the secondary bacterial infection in naturally occurring pneumonia.

Pharmacokinetic/pharmacodynamic integration of tilmicosin against Pasteurella multocida in a piglet tissue cage model.

Tilmicosin is a semi-synthetic macrolide for veterinary use with strong antibacterial effect on respiratory bacteria. In this study, the pharmacokinetic/pharmacodynamic (PK/PD) integration of tilmicosin against Pasteurella multocida (P. multocida) was evaluated by establishing a piglet tissue cage infection model. Concentration of tilmicosin and bacterial numbers of P. multocida in the tissue-cage fluid were monitered. After the population of P. multocida was equal to or greater than 107 CFU/mL in a tissue cage, piglets received an oral administration of tilmicosin at a dose of 30, 40, 50, and 60 mg/kg b.w., once daily for 3 days, respectively. Bacteria were counted every 24 h after drug administration and at 48 and 72 h after the last administration. A sigmoidal Emax model was used to fit the relationship between PK/PD parameters and the antibacterial effect. AUC24h/MIC was the best PK/PD index that correlated with effectiveness of tilmicosin against P. multocida. The magnitude of AUC24h/MIC required for continuous 1/3-log, 1/2-log, and 3/4-log reductions were 19.65 h, 23.86 h, and 35.77 h, respectively, during each 24 h treatment period. In this study, when the dosage was >50 mg/kg, the AUC24h/MIC was still >35.77 h in the period of 24-48 h after the last administration due to the slow elimination, that is, tilmicosin exhibited a potent antibacterial effect against P. multocida after three successive daily administrations. The data provide meaningful guidance to optimize regimens of tilmicosin to treat respiratory tract infections caused by P. multocida.

MOLECULAR CHARACTERIZATION, ANTIBIOTIC SUSCEPTIBILITY AND BIOFILM FORMING ABILITY OF PASTEURELLA MULTOCIDA ISOLATED FROM THE RESPIRATORY MICROBIOTA OF HEALTHY BOVINES

Livestock plays an important role in the economy of the country because it provides food producing animals. Pasteurella multocida which is an opportunistic pathogen of upper respiratory tract of animals and it has been known to cause many harmful diseases may survive in animal body by forming biofilm in different organs. So, the presence of this bacterium in animals may lead to transfer and threaten the human health by food chain. In the last few years, one of the major problems that alarms and evokes a major horrific threat to human being is the bacterial resistance to antimicrobial agents. Due to deficiency of antimicrobial agents in pipeline and emergence of new mechanisms of intra antimicrobial resistance, many surveillance programs have been set up for its containment. Many factors are responsible for this grave situation like high use of antibiotics in animals. So, the current study concluded that all of the 76 isolates of Pasteurella multocida out of 100 samples were confirmed through PCR and found sensitive to florfenicol (100%), gentamycin (92.11%), chloramphenicol (84.21%) and kanamycin (72.37%) respectively. For tetracycline and neomycin sensitivity were (69.73%) and (64.47%) respectively against the bacteria. Whereas tilmicosin and spectinomycin sensitivity were recorded as (30.27%) and (23.69%). Streptomycin (19.73%), sulfadiazine (7.89%), erythromycin (3.94%) and clindamycin (0.0 %) were least sensitive. It was also concluded that when all pure isolates of Pasteurella multocida were tested for Biofilm assay out of 76 isolates categorized as: non biofilm producer (7.89%), weak biofilm producer (34.21%), moderate biofilm producer (46.05%) and strong biofilm producer (11.84%). Hence, it was concluded that Pasteurella multocida isolated from cattle and buffaloes were found to form biofilm in in-vitro condition.

Elderly and their companion animals, cause for pleasure or for harm, a case report of a non-bite Pasteurella multocida bacteremia in an 85-year-old woman with a fatal outcome

We present a case of an elderly woman suffering from Pasteurella multocida (P. multocida) bacteremia, without obvious bite marks, but owning a pet dog. Although the patient was not immunocompromised, and prompt treatment with intravenous antibiotics was initiated, she developed severe septic shock with multiple organ failure and died. In healthy individuals, an infection caused by these bacteria is easy to treat and often harmless, whereas in elderly serious complications can occur. We believe this report of a fatal outcome of a P. multocida bacteremia in a non-immunocompromised, but elderly patient is important, given the growing cohort of elderly pet-owners seeking medical care. A greater awareness of this zoonosis and its potentially fatal outcome is warranted.

Antibody response to 1.0 and 0.5 mL doses of an inactivated bacterial vaccine against bovine respiratory disease in young Holstein calves: a field trial.

Early vaccination of cattle with an inactivated commercial bacterial vaccine against bovine respiratory disease has been reported to increase antibody production and can alleviate the disease. However, its dosage has been little investigated in young Holstein calves. This study addresses the need to establish guide values for vaccine dosage in these animals. Healthy calves received an inactivated vaccine for Histophilus somni, Pasteurella multocida and Mannheimia haemolytica intramuscularly at the ages of 1 and 4 weeks. Administered vaccine doses were 1.0 mL for the primary and booster vaccinations (1.0 + 1.0 group), 0.5 mL for the primary and 1.0 mL for the booster vaccination (0.5 + 1.0 group), or 0.5 mL for both vaccinations (0.5 + 0.5 group). Differences in the vaccine responses between the 1.0 + 1.0 group and 0.5 + 1.0 group were minor. However, the number of calves with a positive vaccine response to H. somni in the 0.5 + 0.5 group was less than half of that in the 1.0 + 1.0 and 0.5 + 1.0 groups. In logistic regression analysis, although the booster vaccination dose was positively correlated with seropositivity for H. somni, the primary vaccination dose was not correlated with vaccine response. The number of calves with positive vaccine responses to M. haemolytica was low even after booster vaccination regardless of the dose. The dose of 0.5 mL can be used for primary vaccinations in newborn Holstein calves, but 1.0 mL may be required for booster vaccinations.

Persistence of maternal antibodies in calves born of combined foot-and-mouth disease + haemorrhagic septicaemia vaccinated buffaloes at organized dairy farm

Twelve apparently healthy and recently parturiated Murrah buffaloes, vaccinated with Foot-and-mouth disease (FMD) + Haemorrhagic septicaemia (HS) combined vaccine at an organized farm along with their newborn calves were inducted for detection of antibodies in serum and colostrum against FMD virus (FMDV) serotypes O, A and Asia-1, and Pasteurella multocida using enzyme linked immunosorbent assay. The calves born to vaccinated dams showed the presence of protective maternal antibody titre (≥1.8 log10) from birth till the period of study (16th week of age) against FMDV serotypes O, A and Asia-1. The maternal antibody titre against P. multocida were protective (≥1.8 log10) till fifth day of age which became partially protective thereafter till the period of study. It is recommended to avoid vaccination of the calves before 16th week of age with FMD+HS combined vaccine.