Pasteurella bacteraemia: Impact of comorbidities on outcome, based on a case series and literature review.

OBJECTIVES: Pasteurella bacteraemia is rare, but has been associated with a high mortality rate. The aim of this study was to estimate the impact of comorbidities on patients with Pasteurella bacteraemia. METHODS: All cases of Pasteurella bacteraemia in adults treated in our centre between January 2008 and December 2017 were included retrospectively and compared with cases identified in a systematic review of the literature via MEDLINE covering the years 1951-2017. The epidemiological, bacteriological, and clinical data were collected, as well as the instances of death after 30 days. RESULTS: Twenty cases of Pasteurella bacteraemia identified in our centre and 99 cases from the literature review were included. A major comorbidity was found in 80/119 (67.2%) patients. The death rate at 30 days was 31.1%. The most common comorbidities were cirrhosis, immunosuppressive therapy, and malignant diseases. Age was not associated with mortality. On multivariate analysis, the only factor associated with mortality was a major comorbidity (odds ratio 2.78, 95% confidence interval 1.01-7.70; p = 0.04). CONCLUSIONS: This study confirms the high mortality rate and highlights the importance of the host background, independent of age, in Pasteurella bacteraemia. Clinicians should be aware of the comorbidities in cases of Pasteurella infection, due to the poor prognosis of bacteraemia.

Emergence of a multidrug-resistant hypervirulent Pasteurella multocida ST342 strain with a floR-carrying plasmid.

OBJECTIVES: To date, very few hypervirulent and multiantibiotic-resistant bacterial strains have been reported. This study reports the first hypervirulent and multiantibiotic-resistant Pasteurella multocida sequence type 342 (ST342) strain (GH161213) isolated from a Pekin duck in China. METHODS: Minimum inhibitory concentrations (MICs) were determined according to Clinical and Laboratory Standards Institute (CLSI) guidelines (VET01-A4, 2013). Determination of the P. multocida GH161213 median lethal dose (LD50) was determined in a mouse model and in ducklings. Plasmid pRCAD0338PM-1 was transferred to Escherichia coli J53Azr by conjugation. The whole genome sequence of P. multocida GH161213 was obtained using an Illumina HiSeq 2500 system. Antimicrobial resistance genes were analysed using the Comprehensive Antibiotic Resistance Database (CARD). RESULTS: Pasteurella multocida GH161213 is a hypervirulent strain with an LD50 of <10 CFU in a mouse model and in ducklings. It also has a high level of multidrug resistance. Strain GH161213 contains a small conjugative plasmid harbouring the floR florfenicol resistance gene. It also contains multiple other antimicrobial resistance mechanisms. CONCLUSION: The genome sequence of P. multocida GH161213 reveals a multidrug-resistant genotype. This is the first reported hypervirulent and multiantibiotic-resistant P. multocida strain.

Characterization of Pasteurella multocida isolated from dead rabbits with respiratory disease in Fujian, China.

BACKGROUND: Pasteurella multocida is one of the important pathogens that infect rabbits, causing major economic losses in commercial rabbit farming. In this study, 205 P. multocida isolates recovered from lungs of dead rabbits with respiratory disease were defined by capsular serogroups, lipopolysaccharide (LPS) genotypes, multi-locus sequence types and screened virulence factors by using PCR assays, and tested antimicrobial susceptibility. RESULTS: The 205 isolates were assigned into 2 capsular types, A and D, and 2 LPS genotypes, L3 and L6. When combining capsular types with LPS genotypes, 4 serotypes were detected. A:L3 (51.22%, 105/205) was the most predominant serotype, followed by A:L6 (24.88%, 51/205), D:L6 (19.02%, 39/205) and D:L3 (4.88%, 10/205). The 205 isolates were grouped into 3 sequence types, ST10, ST11 and ST12. ST12 (56.10%, 115/205) was the most prevalent sequence type, followed by ST10 (24.88%, 51/205) and ST11 (19.02%, 39/205). In the 205 isolates, virulence associated genes ptfA, fur, hgbB, ompA, ompH and oma87 were positive in the PCR screening, whereas the toxA and tbpA genes were negative. Notably, the 156 capsular serogroup A isolates carried the pmHAS gene. All the 205 isolates were susceptible to most of the used antibiotics, except for streptomycin, gentamycin, kanamycin and ceftriaxone, and the resistance rates of which were 27.80, 15.61, 9.27 and 2.44%, respectively. CONCLUSIONS: This study, for the first time, described the prevalence and characteristics of P. multocida causing respiratory disease in rabbits in Fujian Province, which might be useful for tracking the epidemic strains and development of efficient vaccines and methods to prevent and control the pathogen.

Biological characterization of Pasteurella multocida present in the Saiga population.

BACKGROUND: This study provides biochemical and molecular genetic characteristics of P. multocida isolated from dead saigas in 1988, 2010-2015 on the territory of the Republic of Kazakhstan. RESULTS: Bacteriological samples taken from carcasses of saiga antelope during mortality events recorded in West Kazakhstan in both 2010 and 2011 and in Kostanay in 2012 and 2015 confirmed the presence of P. multocida, according to morphological and biochemical characterisation. Only in the event of 2015 was the agent proven to be the causative agent of the disease observed, haemorrhagic septicaemia. In the other mortality events it is not certain if the organism was a primary aetiology or an incidental finding as confirmatory pathological investigation was not undertaken. The implemented phylogenetic analysis of ribosomal RNA 16S gene allowed us to identify Pasteurella strains isolated in 2010-2015 as P. multocida subspecies multocida. Capsular typing by PCR showed that the studied strains isolated from dead saiga in 2010, 2011, 2012 and 2015 belonged to serotype B. MLST analysis showed that these strains of P. multocida are of the capsule type B and form one clonal grouping with isolates ST64, ST44, ST45, ST46, ST44, ST47 which isolated from cases of hemorrhagic septicemia of animals in Hungary, Burma, Sri Lanka, Pakistan and Spain. Sixteen virulence genes of the five strains of P. multocida, isolated from saigas were studied using multiplex PCR. ptfA, ompA, ompH, oma87, plpB, fimA, hsf-2, pfhA, exbB, tonB, hgbA, fur, nanB, nanH and pmHAS genes were detected in all strains. The toxA gene was not identified in the studied strains. The phylogenies of these isolates is compared across saiga populations and years and the 2015 isolate was compared to that of an isolate from a disease outbreak in 1988 and the findings suggest that these isolated bacteria are stable commensals, opportunistically pathogenic, being phylogenetically uniform with very little genetic variation notable over the last 4 decades. CONCLUSION: Isolation, phenotypic and genetic characterization of the P. multocida isolates inform understanding of the epidemiology of infection in saigas and predict virulent potential of these opportunistic bacteria.

Pathogenicity of Pasteurella sp. in lumpsuckers (Cyclopterus lumpus L.).

The incidence of disease caused by Pasteurella sp. in farmed lumpsuckers in Norway has been steadily increasing in recent years, causing significant economic losses and fish welfare issues. The disease affects all life stages, both in hatcheries and after release into salmon cages. Therefore, it is important to establish robust challenge models, to be used for vaccine development. Exposure experiments via intramuscular and intraperitoneal injection underlined the high virulence of the bacteria, whereas the cohabitation and bath models allowed the chronic symptoms of the disease to be studied more accurately. Skin lesions and haemorrhage at the base of fins were observed in the more acute cases of the disease. Symptoms including white spots over the skin, especially around the eyes, characterized the chronic cases. The latter were most prominent from the bath challenge model. Histopathology indicated a systemic pattern of disease, whereas qPCR analysis from head kidney showed that bacteria may be present in survivor fish at the end of the challenges. In all the challenge models investigated, Pasteurella sp. was re-isolated from the fish, thus fulfilling Koch's postulates. These findings highlight the importance of screening of lumpsuckers prior to transfer to minimize the risks of carrying over asymptomatic carriers.

Biofilm formation and avian immune response following experimental acute and chronic avian cholera due to Pasteurella multocida.

Pasteurella multocida is the causative agent of avian cholera, an important economic and ecological disease that can present as a peracute, acute, chronic, or asymptomatic infection. Acute avian cholera is associated with encapsulated P. multocida, while chronic and asymptomatic cases of avian cholera may be associated with capsule-deficient P. multocida isolates. We hypothesize that biofilm formation is also associated with chronic and asymptomatic avian cholera. Experimental infections of chickens with encapsulated, biofilm-deficient P. multocida strain X73, proficient biofilm forming P. multocida strain X73ΔhyaD, and proficient biofilm forming clinical strains 775 and 756 showed that virulence was inversely correlated with biofilm formation. Biofilm-proficient isolates induced chronic avian cholera in the chicken host. Histopathological analysis was used to show that biofilm-proficient isolates induced little inflammation in the lungs, heart, and liver, while biofilm-deficient isolates induced greater inflammation and induced the recruitment of heterophil granulocytes. Putative biofilm matrix material and exopolysaccharide was detected in pulmonary tissue of chickens diagnosed with chronic avian cholera using scanning electron microscopy and a fluorescently-tagged lectin, respectively, supporting a role for biofilm in chronic avian cholera. P. multocida induced Th1 and Th17 immune responses during acute and chronic avian cholera, as determined by quantitative real-time PCR of splenic cytokine genes. Chickens that succumbed to acute avian cholera after experimental challenge with strain X73 had high levels of INF-γ, IL-1ß, IL-6, IL-12A, IL-22, IL-17A, and IL-17RA expressed in the spleen compared to all other experimental groups. Birds infected with capsule-deficient strains had chronic infections lasting 7 days or longer, and had increased levels of IL-17RA, CCR6, and IL-16 compared to non-infected control chickens. However, specific antibody titers increased only transiently to capsule-deficient strains and were low, indicating that antibodies are less important in managing and clearing P. multocida infections.

Comparative analysis of humoral immune responses and pathologies of BALB/c and C57BL/6 wildtype mice experimentally infected with a highly virulent Rodentibacter pneumotropicus (Pasteurella pneumotropica) strain.

BACKGROUND: Mice are a natural host for Rodentibacter (R.) pneumotropicus. Despite specific monitoring, it is still one of the most important infectious agents in laboratory animals. The objective of this study was to determine the virulence of a prevalent pathotype of R. pneumotropicus and characterize the host response in a new animal model. RESULTS: Intranasal infection of C57BL/6 and BALB/c mice with a R. pneumotropicus strain (JF4Ni) bearing the genes of the three known repeats in toxin (RTX) toxins resulted in an unprecedented high mortality and morbidity above 50 and 80%, respectively. Morbidity was associated with severe weight loss as well as conjunctivitis and dyspnea. A main pathology was a catarrhal purulent to necrotic bronchopneumonia. Specific immune globuline (Ig) A was detected in tracheonasal lavages of most surviving mice which were still colonized by R. pneumotropicus. Furthermore, all surviving animals showed a distinct production of IgG antibodies. To differentiate T-helper cell (Th) 1 and Th2 immune responses we used subclasses of IgGs as indicators. Mean ratios of IgG2b to IgG1 were below 0.8 in sera drawn from both mice strains prior infection and from BALB/c mice post infection. In contrast, C57BL/6 mice had a mean IgG2b/IgG1 ratio of 1.6 post infection indicating a Th1 immune response in C57BL/6 versus a Th2 response in BALB/c mice associated with a tenfold higher bacterial load in the lung. In accordance with a Th1 response high antigen-specific IgG2c titers were detected in the majority of surviving C57BL/6 mice. CONCLUSIONS: R. pneumotropicus JF4Ni is a highly virulent strain causing severe pneumonia and septicemia after intranasal infection of C57BL/6 and BALB/c mice. Persisting infections in the two mice strains are associated with Th1 and Th2 immune responses, respectively, and differences in the bacterial burden of the lung. The described model is ideally suited for future vaccination studies using the natural host.

Transcriptomic Analysis on Responses of Murine Lungs to Pasteurella multocida Infection.

Pasteurella multocida infection in cattle causes serious epidemic diseases and leads to great economic losses in livestock industry; however, little is known about the interaction between host and P. multocida in the lungs. To explore a fully insight into the host responses in the lungs during P. multocida infection, a mouse model of Pasteurella pneumonia was established by intraperitoneal infection, and then transcriptomic analysis of infected lungs was performed. P. multocida localized and grew in murine lungs, and induced inflammation in the lungs, as well as mice death. With transcriptomic analysis, approximately 107 clean reads were acquired. 4236 differently expressed genes (DEGs) were detected during P. multocida infection, of which 1924 DEGs were up-regulated. By gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichments, 5,303 GO enrichments and 116 KEGG pathways were significantly enriched in the context of P. multocida infection. Interestingly, genes related to immune responses, such as pattern recognition receptors (PRRs), chemokines and inflammatory cytokines, were significantly up-regulated, suggesting the key roles of these genes in P. multocida infection. Transcriptomic data showed that IFN-γ/IL-17-related genes were increased, which were validated by qRT-PCR, ELISA, and immunoblotting. Our study characterized the transcriptomic profile of the lungs in mice upon Pasteurella infection, and our findings could provide valuable information with respect to better understanding the responses in mice during P. multocida infection.

Septicemic pasteurellosis in farmed elk (Cervus canadensis) in Alberta.

Septicemic pasteurellosis is a bacterial disease of domestic and wild animals including bison, elk, and pronghorn antelope caused by Pasteurella multocida. Here we report 2 cases of septicemic pasteurellosis in farmed elk. Pasteurella multocida serogroup B was isolated from multiple tissues in both animals. Gene sequencing (16S ribosomal RNA) and BLAST query confirmed that the sequence is 99% to 100% homologous to the P. multocida sequences in the database.

Pasteurellose septicémique chez des wapitis d'élevage(Cervus canadensis)en Alberta. La pasteurellose septicémique est une maladie bactérienne des animaux domestiques et sauvages, dont le bison, le wapiti et l'antilocarpe, qui est causée par Pasteurella multocida. Dans le présent article, nous présentons un rapport sur 2 cas de pasteurellose septicémique chez les wapitis d'élevage. Le sérogroupe B de Pasteurella multocida a été isolé dans des plusieurs tissus des deux animaux. Le séquençage des gènes (ARN ribosomique16S) et une recherche BLAST a confirmé que la séquence est de 99 % à 100 % homologue aux séquences de P. multocida dans la base de données.(Traduit par Isabelle Vallières).

Injecting epidemiology into population viability analysis: avian cholera transmission dynamics at an arctic seabird colony.

Infectious diseases have the potential to spread rapidly and cause high mortality within populations of immunologically naïve hosts. The recent appearance of avian cholera, a highly virulent disease of birds caused by the bacterium Pasteurella multocida, at remote Arctic seabird colonies is an emerging conservation concern. Determining disease risk to population viability requires a quantitative understanding of transmission potential and the factors that regulate epidemic persistence. Estimates of the basic (R0 ) and real-time (Rt ) reproductive number are critical in this regard - enumerating the number of secondary infections caused by each primary infection in a newly invaded host population and the decline in transmission rate as susceptible individuals are removed via mortality or immunized recovery. Here, we use data collected at a closely monitored common eider (Somateria mollissima) breeding colony located in the Canadian Arctic to examine transmission and host population dynamics. Specifically, we infer epidemic curves from daily mortality observations and use a likelihood-based procedure to estimate changes in the reproductive number over a series of annual outbreaks. These data are interpreted in relation to concurrent changes in host numbers to assess local extinction risk. Consistent with expectations for a novel pathogen invasion, case incidence increased exponentially during the initial wave of exposure (R0  = 2·5; generation time = 6·5 days ± 1·1 SD). Disease conditions gradually abated, but only after several years of smouldering infection (Rt  ≈ 1). In total, 6194 eider deaths were recorded during outbreaks spanning eight consecutive breeding seasons. Breeding pair abundance declined by 56% from the pre-outbreak peak; however, a robust population of >4000 pairs remained intact upon epidemic fade-out. Overall, outbreak patterns were consistent with herd immunity acting as a mitigating factor governing in the extent and duration of mortality. Disease mortality is frequently modelled as a form of stochastic catastrophe in wildlife population assessments, whereas our approach gives shape to the functional response between transmission and host population dynamics. We conclude that increased emphasis on integrating epidemiological and population processes is essential to predicting the conservation impact of emerging infectious diseases in wildlife.

Avian Cholera Causes Marine Bird Mortality in the Bering Sea of Alaska.

The first known avian cholera outbreak among wild birds in Alaska occurred during November 2013. Liver, intestinal, and splenic necrosis consistent with avian cholera was noted, and Pasteurella multocida serotype 1 was isolated from liver and lung or spleen in Crested Auklets (Aethia cristatella), Thick-billed Murres (Uria lomvia), Common Eider (Somateria mollissima), Northern Fulmars (Fulmarus glacialis), and gulls (Larus spp.).

Feather corticosterone reveals effect of moulting conditions in the autumn on subsequent reproductive output and survival in an Arctic migratory bird.

For birds, unpredictable environments during the energetically stressful times of moulting and breeding are expected to have negative fitness effects. Detecting those effects however, might be difficult if individuals modulate their physiology and/or behaviours in ways to minimize short-term fitness costs. Corticosterone in feathers (CORTf) is thought to provide information on total baseline and stress-induced CORT levels at moulting and is an integrated measure of hypothalamic-pituitary-adrenal activity during the time feathers are grown. We predicted that CORTf levels in northern common eider females would relate to subsequent body condition, reproductive success and survival, in a population of eiders nesting in the eastern Canadian Arctic during a capricious period marked by annual avian cholera outbreaks. We collected CORTf data from feathers grown during previous moult in autumn and data on phenology of subsequent reproduction and survival for 242 eider females over 5 years. Using path analyses, we detected a direct relationship between CORTf and arrival date and body condition the following year. CORTf also had negative indirect relationships with both eider reproductive success and survival of eiders during an avian cholera outbreak. This indirect effect was dramatic with a reduction of approximately 30% in subsequent survival of eiders during an avian cholera outbreak when mean CORTf increased by 1 standard deviation. This study highlights the importance of events or processes occurring during moult on subsequent expression of life-history traits and relation to individual fitness, and shows that information from non-destructive sampling of individuals can track carry-over effects across seasons.

In vitro and in vivo pathogenicity studies of Pasteurella multocida strains harbouring different ompA.

Pasteurella multocida is a pathogenic, Gram-negative bacterium that is commonly found as normal flora in nasopharynx of variety of wild and domestic animals. Numerous virulence factors have been described for P. multocida isolates which include adherence and colonization factors, iron-regulated and acquisition proteins, extracellular enzymes such as neuraminidase, lipopolysaccharide (LPS), capsule and a variety of outer membrane proteins (Omp). OmpA has a significant role in stabilizing the cell envelope structure by providing physical linkage between the outer membrane & peptidoglycan. It has been shown to mediate P. multocida -host cells interaction via heparin and/or fibronectin binding and therefore act as an important invasive molecule which could determine the final outcome of initial infection. Comparative nucleotide sequence analysis of ompA gene of P. multocida has revealed that despite extensive genetic diversity in ompA of P. multocida, most sequences could be classified into two major allele classes namely ompA allele (I) and allele (II). The P. multocida recovered from nasal cavity of bovine and belonging to two ompA classes were tested for their differential virulence. In vitro pathogenicity studies on Madin Darby Bovine Kidney (MDBK) cell line employing adhesion and invasion assays indicated that P. multocida strain with ompA (I) is more invasive than P. multocida strain with ompA (II). In vivo studies in mice further reiterated that the isolates harbouring ompA(I) were comparatively more virulent to isolates harbouring ompA (II).

Acute pasteurellosis in wild big brown bats (Eptesicus fuscus).

We report acute fatal pasteurellosis in wild big brown bats (Eptesicus fuscus) in Wisconsin, USA. Mortality of approximately 100 bats was documented over 4 wk, with no evidence for predatory injuries. Pasteurella multocida serotype 1 was isolated from multiple internal organs from four of five bats examined postmortem.

Avian cholera, a threat to the viability of an Arctic seabird colony?

Evidence that infectious diseases cause wildlife population extirpation or extinction remains anecdotal and it is unclear whether the impacts of a pathogen at the individual level can scale up to population level so drastically. Here, we quantify the response of a Common eider colony to emerging epidemics of avian cholera, one of the most important infectious diseases affecting wild waterfowl. We show that avian cholera has the potential to drive colony extinction, even over a very short period. Extinction depends on disease severity (the impact of the disease on adult female survival) and disease frequency (the number of annual epidemics per decade). In case of epidemics of high severity (i.e., causing >30% mortality of breeding females), more than one outbreak per decade will be unsustainable for the colony and will likely lead to extinction within the next century; more than four outbreaks per decade will drive extinction to within 20 years. Such severity and frequency of avian cholera are already observed, and avian cholera might thus represent a significant threat to viability of breeding populations. However, this will depend on the mechanisms underlying avian cholera transmission, maintenance, and spread, which are currently only poorly known.

Comparison of genotypic and phenotypic characterization methods for Pasteurella multocida isolates from fatal cases of bovine respiratory disease.

Bovine respiratory disease (BRD) is the most costly disease of beef cattle in North America. Because Pasteurella multocida is a commensal of the upper respiratory tract, it is generally considered an opportunistic pathogen. However, studies in swine indicated that there may be a limited number of strains associated with disease, suggesting that some are more virulent than others. Although this may also be true of isolates from cattle, appropriate typing methods must be established before this possibility can be investigated. The purpose of this study was to compare effectiveness of polymerase chain reaction (PCR) fingerprinting to more traditional approaches for typing bovine P. multocida isolates. Isolates were obtained from 41 cases of fatal BRD and subjected to random amplified polymorphic DNA PCR (RAPD-PCR), whole cell protein (WCP) profiles, outer membrane protein (OMP) profiles, and serotyping. The discrimination index was calculated for each typing method and combinations of each using Simpson's index of diversity. Correlation coefficients were calculated to assess concordance between classification results achieved through genotypic (RAPD-PCR) and phenotypic (WCP, OMP, and serotyping) approaches. All characterization methods were capable of discriminating between isolates. However, there was poor concordance between techniques. There were also few significant associations between typing results and epidemiologic data. Random amplified polymorphic DNA PCR was validated as being a repeatable and reliable means of discriminating between P. multocida isolates obtained from cattle. Isolates obtained from fatal cases of BRD in calves in a commercial feedlot demonstrated significant diversity, justifying additional investigation into whether P. multocida is a strictly opportunistic pathogen in cattle.

Variation in Pasteurella (Bibersteinia) and Mannheimia spp. following transport and antibiotic treatment in free-ranging and captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis).

Morbidity and mortality associated with respiratory disease following capture and translocation of bighorn sheep (Ovis canadensis canadensis) is a significant concern, particularly when establishing new or augmenting existing bighorn populations. Administration of prophylactic antibiotics at the time of capture is often done to minimize the risk of respiratory disease, but the efficacy of this practice is unknown. The effects of oxytetracycline and florfenicol on the Pasteurella (Bibersteinia) and Mannheimia spp. isolated from samples collected from the oropharynx at the time of capture and 3 or 42 day later were evaluated in two groups of bighorn sheep. The most evident change in the isolation rates or types of Pasteurella (Bibersteinia) spp., Mannheimia spp., or both was an increase of beta-hemolytic strains isolated from bighorn sheep 3 day following oxytetracycline treatment. Both groups of bighorn sheep carried Pasteurella (Bibersteinia) trehalosi identified as the same biovariants, but they did not share biovariants of Mannheimia spp. No animals had signs of respiratory disease. Isolates representative of all biovariants present in cultures from the two bighorn sheep groups were sensitive to in vitro tests to both oxytetracycline and florfenicol and the majority were also sensitive to seven other antibiotics tested. The administration of neither oxytetracycline nor florfenicol eliminated Pasteurella (Bibersteinia) or Mannheimia from the oropharyngeal mucosa. Resistance to either antibiotic used in these animals was not noted. Although the prophylactic benefits of these drugs in preventing disease are uncertain, therapeutic levels of antibiotics in lung tissue during times of stress may reduce the risk of disease. Representative sampling of the oropharyngeal microflora of bighorn sheep source and recipient populations prior to being intermingled should be considered as one of the tools to minimize exposure of naive populations to potentially pathogenic bacteria.

Neonatal pasteurellosis: a review of reported cases.

BACKGROUND: Pasteurellosis is an uncommon infectious disease in humans mainly caused by Pasteurella multocida infection in neonates and has been rarely reported. OBJECTIVES: To review the literature and address the mode of transmission, clinical presentation, laboratory diagnosis, treatment, outcome and potential risk factors related to neonatal pasteurellosis. METHODS: A Medline all-languages database search for neonatal (birth-1 month) pasteurellosis cases after 1950 was conducted. Individual references from each publication were also reviewed to identify additional cases. RESULTS: Thirty-two cases were found, but detailed information was available for this review in only 25 cases. The median age was 14 days (range: birth-30 days). All were infected with P multocida. Animal exposure to cats and/or dogs was the major risk of infection: non-traumatic exposure in 11 (44%) cases, and traumatic exposure in 2 (8%) cases. Infections in 11 (44%) cases were classified as vertical transmission. The clinical features were most commonly bacteraemia with or without meningitis. The age at onset of 72 h or older was significantly associated with meningitis (> or = 72 h of age: 13/14 vs <72 h of age: 3/11, p = 0.002). The most used antibiotics were beta-lactam with or without aminoglycoside or chloramphenicol. The overall mortality was 20% (5/25). The age at presentation of <72 h, birth weight of <2500 g, and vertical transmission were independently associated with death. CONCLUSION: Pasteurellosis is a rare bacterial infection in neonates and should be considered in the cases of sepsis with history of exposure to domestic animal in either the patient or the mother.