Comparative analysis of the pulmonary microbiome in healthy and diseased pigs.

The lungs possess an effective antimicrobial system and a strong ability to eliminate microorganisms in healthy organisms, and were once considered sterile. With the development of culture-independent sequencing technology, the richness and diversity of porcine lung microbiota have been gaining attention. In order to study the relationship between lung microbiota and porcine respiratory disease complex (PRDC), the lung microbiota in healthy and diseased swine bronchoalveolar lavage fluids were analyzed and compared using the Illumina MiSeq sequencing platform. The predominant microbial communities of healthy and diseased swine were similar at the phylum level, mainly composed of Proteobacteria, Firmicutes, Tenericutes, and Bacteroidetes. However, the bacterial taxonomic communities of healthy and diseased swine differed at the genus level. The higher relative abundances of Lactococcus, Enterococcus, Staphylococcus, and Lactobacillus genera in healthy swine might provide more benefits for lung health, while the enhanced richness of Streptococcus, Haemophilus, Pasteurella, and Bordetella genera in diseased swine might be closely related to pathogen invasion and the occurrence of respiratory disease. In conclusion, the observed differences in the richness and diversity of lung microbiota can provide novel insights into their relationship with PRDC. Analyses of swine lung microbiota communities might produce an effective strategy for the control and prevention of respiratory tract infections.

Genetic parameters of resistance to pasteurellosis using novel response traits in rabbits.

BACKGROUND: Pasteurellosis (Pasteurella infection) is one of the most common bacterial infections in rabbits on commercial farms and in laboratory facilities. Curative treatments using antibiotics are only partly efficient, with frequent relapses. Breeding rabbits for improved genetic resistance to pasteurellosis is a sustainable alternative approach. In this study, we infected 964 crossbred rabbits from six sire lines experimentally with Pasteurella multocida. After post-mortem examination and bacteriological analyses, abscess, bacteria, and resistance scores were derived for each rabbit based on the extent of lesions and bacterial dissemination in the body. This is the first study to use such an experimental design and response traits to measure resistance to pasteurellosis in a rabbit population. We investigated the genetic variation of these traits in order to identify potential selection criteria. We also estimated genetic correlations of resistance to pasteurellosis in the experimental population with traits that are under selection in the breeding populations (number of kits born alive and weaning weight). RESULTS: Heritability estimates for the novel response traits, abscess, bacteria, and resistance scores, ranged from 0.08 (± 0.05) to 0.16 (± 0.06). The resistance score showed very strong negative genetic correlation estimates with abscess (- 0.99 ± 0.05) and bacteria scores (- 0.98 ± 0.07). A very high positive genetic correlation of 0.99 ± 0.16 was estimated between abscess and bacteria scores. Estimates of genetic correlations of the resistance score with average daily gain traits for the first and second week after inoculation were 0.98 (± 0.06) and 0.70 (± 0.14), respectively. Estimates of genetic correlations of the disease-related traits with average daily gain pre-inoculation were favorable but with high standard errors. Estimates of genetic and phenotypic correlations of the disease-related traits with commercial selection traits were not significantly different from zero. CONCLUSIONS: Disease response traits are heritable and are highly correlated with each other, but do not show any significant genetic correlations with commercial selection traits. Thus, the prevalence of pasteurellosis could be decreased by selecting more resistant rabbits on any one of the disease response traits with a limited impact on the selection traits, which would allow implementation of a breeding program to improve resistance to pasteurellosis in rabbits.

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.

In Vitro Activity of Pexiganan and 10 Comparator Antimicrobials against 234 Isolates, Including 93 Pasteurella Species and 50 Anaerobic Bacterial Isolates Recovered from Animal Bite Wounds.

Animal bite wounds affect more than 5 million Americans annually, resulting in 300,000 emergency department visits, 10,000 hospitalizations, and an untold number of physician office visits. Various forms of topical therapy are empirically self-employed by many patients prior to seeking medical attention. Pexiganan, a 22-amino-acid synthetic cationic analogue of the peptide magainin II, acts by selectively damaging bacterial cell membranes. We determined the MICs for pexiganan and other antimicrobial agents often used for treatment of bite wounds. Most isolates were from U.S. patients, and ∼10% were from European and Canadian patients. The comparator antimicrobials studied were penicillin, amoxicillin-clavulanate, piperacillin-tazobactam, meropenem, clindamycin, doxycycline, moxifloxacin, ceftriaxone, linezolid, and metronidazole. The MIC90s of pexiganan were 32 µg/ml (against Pasteurella multocida subsp. multocida), 16 µg/ml (P. multocida subsp. septica, Pasteurella canis, and Pasteurella dagmatis), 8 µg/ml (Pasteurella stomatis), 8 µg/ml (Eikenella corrodens), 2 µg/ml (Neisseria weaveri, Neisseria zoodegmatis, and Moraxella canis-Moraxella lacunata group), 16 µg/ml (Bergeyella zoohelcum), 64 µg/ml (Bacteroides pyogenes), 4 µg/ml (Fusobacterium russii), 32 µg/ml (Fusobacterium canifelinum), and 64 µg/ml (Prevotella heparinolytica). The concentration of pexiganan in the cream used was 8,000 µg/ml, more than 60 to 100 times the highest MIC obtained. Pexiganan exhibited a broad range of antimicrobial activity, showing potential for treating animal bite infections. A clinical trial seems warranted.

Total Synthesis and Antimicrobial Activity of Chlorocatechelin A.

Chlorocatechelin A (1) is a structurally unique microbial siderophore containing two units of 4-chloro-2,3-dihydroxybenzoic acid (CDB) and a characteristic acylguanidine structure. Purification from the microbe culture is not an easy task due to the lability of the acylguanidine and its chelating nature. Here we report the first convergent total synthesis and antimicrobial activity of chlorocatechelin A (1). The bis-acylated arginine was constructed using a Schotten-Baumann reaction whereas the CDB component was synthesized from o-vanillin (8). Condensation with an ornithine derivative synthesized from 1-benzyl d-glutamate was followed by deprotection in basic and neutral conditions to complete the total synthesis. We examined the antimicrobial activity of chlorocatechelin A (1) and found that this siderophore was active against desferrioxamine B (DFB)-sensitive microbes including the fish pathogen Pasteurella piscicida.

Bibersteinia trehalosi inhibits the growth of Mannheimia haemolytica by a proximity-dependent mechanism.

Mannheimia (Pasteurella) haemolytica is the only pathogen that consistently causes severe bronchopneumonia and rapid death of bighorn sheep (BHS; Ovis canadensis) under experimental conditions. Paradoxically, Bibersteinia (Pasteurella) trehalosi and Pasteurella multocida have been isolated from BHS pneumonic lungs much more frequently than M. haemolytica. These observations suggest that there may be an interaction between these bacteria, and we hypothesized that B. trehalosi overgrows or otherwise inhibits the growth of M. haemolytica. Growth curves (monoculture) demonstrated that B. trehalosi has a shorter doubling time ( approximately 10 min versus approximately 27 min) and consistently achieves 3-log higher cell density (CFU/ml) compared to M. haemolytica. During coculture M. haemolytica growth was inhibited when B. trehalosi entered stationary phase (6 h) resulting in a final cell density for M. haemolytica that was 6 to 9 logs lower than expected with growth in the absence of B. trehalosi. Coculture supernatant failed to inhibit M. haemolytica growth on agar or in broth, indicating no obvious involvement of lytic phages, bacteriocins, or quorum-sensing systems. This observation was confirmed by limited growth inhibition of M. haemolytica when both pathogens were cultured in the same media but separated by a filter (0.4-microm pore size) that limited contact between the two bacterial populations. There was significant growth inhibition of M. haemolytica when the populations were separated by membranes with a pore size of 8 mum that allowed free contact. These observations demonstrate that B. trehalosi can both outgrow and inhibit M. haemolytica growth with the latter related to a proximity- or contact-dependent mechanism.

Identification of Riemerella anatipestifer genes differentially expressed in infected duck livers by the selective capture of transcribed sequences technique.

Riemerella anatipestifer is the causative agent of duck septicaemia. Determination of R. anatipestifer virulence mechanisms will help us to effectively control this contagious agent. The differentially expressed gene profile of R. anatipestifer in infected duck livers was therefore identified and compared with in vitro cultures by selective capture of transcribed sequences analysis. A total of 48 genes were identified, of which 43 were genes that encode enzymes for amino acid biosynthesis and metabolism, intermediary metabolism, and energy metabolism, or proteins for regulatory adaptive responses, general microbial stress response, transport proteins and secreted proteinases. Five were unknown, novel genes. Eight genes representing the categories were randomly chosen and verified by real-time reverse transcriptase-polymerase chain reaction analysis. All were upregulated by R. anatipestifer in infected duck livers, with changes ranging from 1.44-fold to 4.62-fold compared with in vitro cultures. The results from the present study revealed a gene expression profile of R. anatipestifer in infected duck livers. The unknown but novel genes may be potential novel virulence factors for R. anatipestifer. In conclusion, the data from this study will provide a molecular basis for further study of R. anatipestifer pathogenesis.

[Pasteurella] caballi infection not limited to horses - a closer look at taxon 42 of Bisgaard.

AIM: To investigate if taxon 42 of Bisgaard isolated from pigs represents genuine [Pasteurella] caballi, which was previously only isolated from horses. METHODS AND RESULTS: A total of 15 field isolates from horses and pigs from five different countries representing three continents were subjected to extended phenotypical characterization. Although minor differences were observed between taxon 42 and [P.] caballi, these differences did not allow phenotypic separation. Ribotyping based on HindIII digestion showed five profiles based on nine band positions. One [P.] caballi strain and two taxon 42 strains shared the same profile. Ribotyping using HpaII gave a higher diversity with nine profiles based on ten band positions. While no profiles were shared between the taxon 42 and [P.] caballi strains, pattern analysis showed that two of the taxon 42 isolates were most similar (91% similarity) with a [P.] caballi isolate. The 16S rRNA gene sequencing of one strain of taxon 42 and one strain of [P.] caballi was performed and compared with the published sequence for the type strain of [P.] caballi. The three strains showed nearly identical sequences with at least 99.8% similarity. DNA re-associations measured by the micro-well method were 79 and 77%, respectively between the type strain of [P.] caballi and two strains of taxon 42 representing distinct ribotypes and confirmed that taxon 42 belongs to [P.] caballi. CONCLUSION: The present investigation documents that [P.] caballi can be isolated from clinical respiratory specimens from pigs and the recognized association with respiratory infections in horses and horse bite infection in humans. Strains classified as taxon 42 are [P.] caballi isolated from pigs and for both pigs and horses, lesions mainly include the respiratory tract. SIGNIFICANCE AND IMPACT OF THE STUDY: The results will improve the diagnostics and progress studies of virulence and epidemiology of [P.] caballi.

Cat bite wound infections: a prospective clinical and microbiological study at three emergency wards in Stockholm, Sweden.

OBJECTIVE: The rate of infection following cat bites appears to be greater than that from dog bites. To study the clinical picture, complications and microbiology (in humans and cats), this prospective study was performed. METHODS: A prospective study with patients with clinical symptoms of infection due to cat bites from three emergency wards during two years in Stockholm, Sweden. Aerobic and anaerobic cultures from the wounds were performed as well as cultures from the biting cat's mouth. Clinical data and complications were registered. RESULTS: Seventy-nine episodes in 78 patients with infective cat bites were included. Pasteurella multocida was isolated in 70% of the patients; in addition anaerobic pathogens were isolated in 16% concurrently with P. multocida, while Staphylococcus aureus was isolated in only two patients. Pasteurella spp. was also isolated from 80% of the pharynx of the biting cats. The dominating symptoms of infection were erythema, pain and oedema, often emerging as early as 3h after the bite. Complications such as tendosynovitis, arthritis, abscesses and septicaemia occurred in 18% of the patients. No patient died due to the infection. The majority of the patients received penicillin or amoxicillin as antibiotic treatment. CONCLUSIONS: P. multocida was the dominating pathogen among patients with infected cat bites and antibiotic treatment should cover P. multocida.

[Pasteurella: insights into the virulence determinants of a heterogenous bacterial type]. / Pasteurella: Einblicke in die Virulenzeigenschaften einer heterogenen Bakterien-Gattung.

Pasteurella (P.) multocida is the causative agent of numerous economically relevant diseases worldwide. These are enzootic bronchopneumonia in cattle and sheep and hemorraghic septicemia in cattle and buffaloes, Rhinitis atrophicans in swine, snuffles in rabbit, and fowl cholera. All disease complexes are associated with certain capsular and somatic antigens. Even as human pathogen P. multocida is of increasing importance, causing wound infections, and even septicemia, meningitis, and endocarditis. Despite extensive research activities including the genome analysis of one fowl cholera isolate in the year 2001 there are a lot of open questions concerning the molecular pathogenic mechanisms. Problems encountered are the high antigenic variability and the wide host spectrum of P. multocida as well as different courses of infection. In consequence there are enormous difficulties in producing vaccines. Transcriptomics and proteomics hopefully will give new insight into the pathogenesis of P. multocida infections in different hosts. A frequent problem particular in classical diagnostic laboratories is the diagnosis of P. multocida and its differentiation from other P. species and Mannheimia (M.) haemolytica. The biochemical identification of P. multocida is not reliable due to variable phenotypical characteristics often caused by different culture conditions, and it is time consuming and cost-intensive. Extensive molecular biologic studies concerning the prevalence and distribution of virulence associated genes known so far in P. species, which will be described in detail in this paper, could contribute to the establishment of a diagnostic tool, such as a multiplex polymerase chain reaction, that would provide a cheap and time-saving identification and characterization of wildtype strains.

Studies on the occurrence of Gram-negative bacteria in ticks: Ixodes ricinus as a potential vector of Pasteurella.

A total of 372 Ixodes ricinus ticks (101 females, 122 males, and 149 nymphs) collected by flagging in 6 mixed woodlands of eastern Poland were examined by culture for the presence of internal Gram-negative bacteria other than Borrelia burgdorferi. Adult ticks were examined in pools of 2 specimens each and nymphs were examined in pools of 3-5 specimens each. Ticks were disinfected in 70 % ethanol and homogenized in 0.85% NaCl. The diluted homogenate was inoculated onto 3 kinds of agar media: buffered charcoal yeast extract (BCYE-alpha) for isolation of fastidious Gram-negative bacteria, eosin methylene blue agar (EMB) for isolation of enterobacteria, and tryptic soya agar for isolation of all other non-fastidious Gram-negative bacteria. The Gram-negative isolates were identified with the API Systems 20E and NE microtests. A total of 9 species of Gram-negative bacteria were identified, of which the commonest were strains determined as Pasteurella pneumotropica/haemolytica, which were isolated on BCYE-alpha agar from ticks collected in all 6 examined woodlands. The total number of these strains (49) exceeded the total number of all other strains of Gram-negative bacteria recovered from ticks (30). Of the total number of examined ticks, the minimum infection rate with Pasteurella pneumotropica/haemolytica was highest in females (18.8%), and slightly lower in males (12.3%) and nymphs (10%). Besides Pasteurella pneumotropica/haemolytica, the following species of Gram-negative bacteria were isolated from examined ticks: Pantoea agglomerans, Serratia marcescens, Serratia plymuthica on EMB agar and Aeromonas hydrophila, Burkholderia cepacia, Chromobacterium violaceum, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia on tryptic soya agar. Minimal infection rates with these bacteria were low, ranging from 0.7-5.9%. Of the isolated bacteria, Chromobacterium violaceum, Pasteurella pneumotropica/haemolytica, Pseudomonas aeruginosa, and Serratia marcescens are potentially pathogenic for man and/or animals. In particular, the common occurrence of Pasteurella pneumotropica/haemolytica in Ixodes ricinus ticks poses a potential risk of pasteurellosis for humans and animals exposed to tick bites.

Evaluation of a forced-air-ventilated micro-isolation system for protection of mice against Pasteurella pneumotropica.

Studies to date have established that the physical environment inside cages can be controlled adequately by setting the intra-cage ventilation at 60 air changes per hour in a forced-air-ventilated micro-isolation system (FVMIS). In this study, the capability of FVMIS to prevent inter-cage transmission of microorganisms was evaluated using Pasteurella pneumotropica as a reference microorganism. One FVMIS rack and a conventional rack were used, and cages with mice positive for P. pneumotropica and those with P. pneumotropica-free mice were housed on both racks. The mice were examined for P. pneumotropica contamination every 4 weeks after initiating the experiment for 12 weeks using a polymerase chain reaction method. Some P. pneumotropica-free mice housed in open air cages in the conventional rack became positive for P. pneumotropica (four of 28 animals after 4 weeks; eight of 28 animals after 12 weeks), but all P. pneumotropica-free mice housed in the FVMIS cages remained negative for the bacterium throughout the experiment. The results demonstrate that FVMIS can prevent inter-cage transmission of P. pneumotropica when proper cage handling practice is under taken.

[Human pasteurellosis: diagnosis, treatment and precautions]. / Le diagnostic, le traitement et la prévention des pasteurelloses humaines.

The circumstances of diagnosis of human pasteurellosis are reviewed. The diagnosis is usually suspected for animal bite or scratch wounds. Conversely, in other infections the diagnosis is only based on bacteriological data. Phenotypic misidentification of Pasteurellaceae from clinical material is common. The phenotypic criteria of identification of the six species of human pathogen Pasteurella are presented. We emphasise that bite wound specimens have to be cultured for aerobic and anaerobic bacteria and yield an average of 5 bacterial isolates per culture. Antibiotic therapy relies upon amino-penicillins or cephalosporins, although b-lactamase producing strains are scarce. Fluoroquinolones can be an alternative for systemic infections. Molecular typing unequivocally points out the risk of transmission from pets to humans. Immunocompromised persons have to be made aware of precautions.

Toll-like receptor 4-positive macrophages protect mice from Pasteurella pneumotropica-induced pneumonia.

This study investigates Toll-like receptor 4 (TLR4)-positive macrophages in early recognition and clearance of pulmonary bacteria. TLR4 is a trans-membrane receptor that is the primary recognition molecule for lipopolysaccharide of gram-negative bacteria. The TLR4(Lps-del) mouse strains C57BL10/ScN (B10) and STOCK Abb(tm1) TLR4(Lps-del) Slc11a1(s)(B10 x C2D) are susceptible to pulmonary infections and develop pneumonia when naturally or experimentally infected by the opportunistic bacterium Pasteurella pneumotropica. Since these mice have the TLR4(Lps-del) genotype, we hypothesized that reconstitution of mice with TLR4-positive macrophages would provide resistance to this bacterium. A cultured macrophage cell line (C2D macrophages) and bone marrow cells from C2D mice were adoptively transferred to B10 and B10 x C2D mice by intraperitoneal injection. C2D macrophages increased B10 and B10 x C2D mouse resistance to P. pneumotropica. In C2D-recipient mice there was earlier transcription of tumor necrosis factor alpha and chemokines JE and macrophage inflammatory protein 2 (MIP-2) in the lungs of B10 and B10 x C2D mice, and there was earlier transcription of KC and MIP-1alpha in B10 x C2D mice. In addition, the course of inflammation following experimental Pasteurella challenge was altered in C2D recipients. C2D macrophages also protected B10 x C2D mice, which lack CD4(+) T cells. These data indicate that macrophages are critical for pulmonary immunity and can provide host resistance to P. pneumotropica. This study indicates that TLR4-positive macrophages are important for early recognition and clearance of pulmonary bacterial infections.

Mannheimia haemolytica serotype 1 and Pasteurella trehalosi serotype 10 culture supernatants contain fibrinogen-binding proteins.

Fibrinogen-binding proteins were found in the culture supernatants of Mannheimia haemolytica serotype 1 (ATCC 43270) and Pasteurella trehalosi serotype 10 (ECO-100). Sheep fibrinogen was biotinylated and shown to bind to proteins in the culture supernatants by modified western blot. Fibrinogen-binding proteins in the culture supernatant may be important virulence factors leading to the characteristic fibrinous pneumonia caused by these organisms and may be critical antigenic targets for immune prophylaxis.

Pathology of an atypical strain of Pasteurella gallinarum infection in chickens.

Gross and microscopic pathology caused by an atypical strain of Pasteurella gallinarum (Fresno strain) was compared in chickens with that caused by the American Type Culture Collection type strain. Ten 21-day-old broiler chickens were inoculated intranasally with 10(7) colony forming units or intramuscularly with 10(5) colony forming units of either strain. The birds were killed 7 days later, and gross and microscopic lesions were studied. Grossly, there was extensive white discoloration of pectoral muscles with mild fibrinous exudate in birds inoculated intramuscularly with the Fresno strain of P. gallinarum. Most of these birds also had severe fibrinous exudation over the heart, the capsule of the liver, the air sac, and in the hock joints. Microscopically, there was severe chronic pyogranulomatous airsacculitis, pericarditis, perihepatitis, myositis, synovitis, and granulomatous pneumonia. One bird had severe acute multifocal hepatitis. From this study, it is evident that the Fresno strain of P. gallinarum was more pathogenic than the American Type Culture Collection type strain when given intramuscularly.

Mosaic structure and molecular evolution of the leukotoxin operon (lktCABD) in Mannheimia (Pasteurella) haemolytica, Mannheimia glucosida, and Pasteurella trehalosi.

The mosaic structure and molecular evolution of the leukotoxin operon (lktCABD) was investigated by nucleotide sequence comparison of the lktC, lktB, and lktD genes in 23 Mannheimia (Pasteurella) haemolytica, 6 Mannheimia glucosida, and 4 Pasteurella trehalosi strains. Sequence variation in the lktA gene has been described previously (R. L. Davies et al., J. Bacteriol. 183:1394-1404, 2001). The leukotoxin operon of M. haemolytica has a complex mosaic structure and has been derived by extensive inter- and intraspecies horizontal DNA transfer and intragenic recombination events. However, the pattern of recombination varies throughout the operon and among the different evolutionary lineages of M. haemolytica. The lktA and lktB genes have the most complex mosaic structures with segments derived from up to four different sources, including M. glucosida and P. trehalosi. In contrast, the lktD gene is highly conserved in M. haemolytica. The lktC, lktA, and lktB genes of strains representing the major ovine lineages contain recombinant segments derived from bovine or bovine-like serotype A2 strains. These findings support the previous conclusion that host switching of bovine A2 strains from cattle to sheep has played a major role in the evolution of the leukotoxin operon in ovine strains of M. haemolytica. Homologous segments of donor and recipient alleles are identical, or nearly identical, indicating that the recombinational exchanges occurred relatively recent in evolutionary terms. The 5' and 3' ends of the operon are highly conserved in M. haemolytica, which suggests that multiple horizontal exchanges of the complete operon have occurred by a common mechanism such as transduction. Although the lktA and lktB genes both have complex mosaic structures and high nucleotide substitution rates, the amino acid diversity of LktB is significantly lower than that of LktA due to a higher degree of evolutionary constraint against amino acid replacement. The recombinational exchanges within the leukotoxin operon have had greatest effect on LktA and probably provide an adaptive advantage against the host antibody response by generating novel antigenic variation at surface-exposed sites.

Pathogenicity and drug susceptibility of the Pasteurella anatis isolated in chickens in Taiwan.

A strain of Pasteurella anatis (PA) was isolated from the sinus of an adult leghorn laying chicken with sinusitis, nasal discharge, drop in egg production, and low mortality, symptoms initially thought to indicate infectious coryza. The tiny, smooth, whitish colonies were identified as PA. To compare its pathogenicity with that of commercial broilers, nine groups, 10 birds per group, of 10-day-old broilers were individually inoculated with the strain of PA, Pasteurella multocida (PM), or Escherichia coli (EC) by intravenous, intraperitoneal, intramuscular, or subcutaneous inoculation. The PA was determined to cause the signs, lesions, and septicemic death, which are similar to the symptoms of PM or EC infection. At 1 wk postinfection (PI), the mortality rate was between that of PM and EC infection at 1 wk PI. Twenty antimicrobial-containing discs were evaluated, and the isolate was highly sensitive to cetiofer, amoxicillin, lincopectin, and furazolidone. Furthermore, it was moderately sensitive to tetracycline and enrofloxacin and only slightly sensitive to cephalothin, chloramphenicol, flumequine, nalidixic acid, neomycin, oxolinic acid, streptomycin, and trimethoprim. The PA infection was treated successfully with amoxicillin.

Toxoplasmic encephalitis in a free-ranging Rocky Mountain bighorn sheep from Washington.

A 4-mo-old free-ranging Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from the Hells Canyon area (Washington, USA) was diagnosed with encephalitis associated with Toxoplasma gondii infection. The sheep had concurrent pneumonic pasteurellosis and resided in a geographic area with endemic Pasteurella-associated pneumonia and mortality in bighorn sheep. The brain had multifocal necrotizing and nonsuppurative encephalitis with intralesional protozoa. The protozoa were identified as T. gondii by immunohistochemistry. To our knowledge, this is the first report of T. gondii infection in a Rocky Mountain bighorn sheep.