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experimentally induced pneumonia in scid/beige mice, using a bovine isolate of pasteurella haemolytica.intranasal challenge of immunocompetent mice with pasteurella haemolytica results in little or no pulmonary inflammation. the study reported here was designed to investigate the inflammatory response in the lungs of immunodeficient scid/beige mice after similar challenge.200010857006
efficacy of difloxacin in calves experimentally infected with mannheimia haemolytica.to determine the efficacy of difloxacin, a novel fluoroquinolone antibiotic, in calves experimentally infected with mannheimia haemolytica (formerly pasteurella haemolytica).200010850850
dna-dna hybridization determined in micro-wells using covalent attachment of dna.the present study was aimed at reducing the time and labour used to perform dna-dna hybridizations for classification of bacteria at the species level. a micro-well-format dna hybridization method was developed and validated. dna extractions were performed by a small-scale method and dna was sheared mechanically into fragments of between 400 and 700 bases. the hybridization conditions were calibrated according to dna similarities obtained by the spectrophotometric method using strains within the ...200010843050
epidemiology of infectious keratoconjunctivitis in cattle in south-east ethiopia.the aim of the study was to determine the prevalence of infectious keratoconjunctivitis on cross-breed dairy farms and to evaluate factors that influence its distribution. a total of 11 dairy farms and one cattle cross-breeding farm in different parts of arsi region, south-east ethiopia were clinically and bacteriologically investigated from february 1989 to december 1990. out of 5221 local zebu and cross-breed dairy animals, 110 were found to have different degrees of infectious bovine keratoco ...200010842466
the lactoperoxidase system functions in bacterial clearance of airways.airway mucus is a complex mixture of secretory products that provides a multifaceted defense against pulmonary infection. mucus contains antimicrobial peptides (e.g., defensins) and enzymes (e.g., lysozyme) although the contribution of these to airway sterility has not been tested in vivo. we have previously shown that an enzymatically active, heme-containing peroxidase comprises 1% of the soluble protein in sheep airway secretions, and it has been hypothesized that this airway peroxidase may fu ...200010837362
apx toxins in pasteurellaceae species from animals.pasteurellaceae species particularly of porcine origin which are closely related to actinobacillus pleuropneumoniae were analyzed for the presence of analogues to the major a. pleuropneumoniae rtx toxin genes, apxicabd, apxiica and apxiiicabd and for their expression. actinobacillus suis contains both apxicabd(var.suis) and apxiica(var. suis) operons and was shown to produce apxi and apxii toxin. actinobacillus rossii contained the operons apxiica(var.rossii) and apxiiicabd(var.rossii). however, ...200010831858
isolation of respiratory bovine coronavirus, other cytocidal viruses, and pasteurella spp from cattle involved in two natural outbreaks of shipping fever.to identify cytocidal viruses and pasteurella spp that could be isolated from cattle involved in 2 natural outbreaks of shipping fever.200010825949
the potential role of the arthus and shwartzman reactions in the pathogenesis of pneumonic pasteurellosis.pneumonic pasteurellosis (pp) is an economically important disease in cattle, sheep, and goats. pasteurella haemolytica is commonly isolated from the severe fibrinopurulent pneumonia that characterize this respiratory syndrome. during infection, the bacteria produce leukotoxin (lkt) and lipopolysaccharide (lps), both potent inducers of inflammation. nonetheless, it has also been demonstrated that an exacerbated host's inflammatory response is responsible for the severe lung damage. despite resea ...200010807496
a 24-kda cloned zinc metalloprotease from actinobacillus pleuropneumoniae is common to all serotypes and cleaves actin in vitro.actinobacillus pleuropneumoniae causes pleuropneumonia in swine. this bacterium secretes proteases that degrade porcine hemoglobin and iga in vitro. to further characterize a. pleuropneumoniae proteases, we constructed a genomic library expressed in escherichia coli dh5alpha, and selected a clone that showed proteolytic activity. the recombinant plasmid carries an 800-base pair a. pleuropneumoniae gene sequence that.codes for a 24-kda polypeptide. a 350-base pair psti fragment from the sequence ...200010805246
effects of tilmicosin treatment on pasteurella haemolytica organisms in nasal secretion specimens of calves with respiratory tract disease.to determine the effect of tilmicosin treatment on number of pasteurella haemolytica (ph) organisms in nasal secretion specimens of calves with respiratory tract disease.200010803647
evaluation of structural and functional alterations of circulating neutrophils in calves with experimentally induced pneumonic pasteurellosis.to determine the structural and functional alterations in circulating neutrophils that may lead to sequestration in lung microvasculature and endothelial injury in calves with experimentally induced pneumonic pasteurellosis.199910791946
fnrp interactions with the pasteurella haemolytica leukotoxin promoter.pasteurella haemolytica fnrp is homologous to fnr, the global transcriptional regulator of anaerobic respiration in escherichia coli. to investigate the role of o(2) in the expression of p. haemolytica leukotoxin, we tested a lktc::lacz fusion constructed in e. coli for a fnrp-mediated regulatory effect under aerobic and anaerobic growth conditions. both e. coli fnr and fnrp suppressed leukotoxin transcription under aerobic conditions. under anaerobic conditions, fnr suppressed transcription, wh ...200010779715
association among filamentous actin content, cd11b expression, and membrane deformability in stimulated and unstimulated bovine neutrophils.to investigate rheologic properties of bovine neutrophils that may result in adhesion molecule-independent sequestration of neutrophils in inflamed lungs of cattle.200010772101
functional analysis of plp1 and plp2, two homologues of phosducin in yeast.mammalian phosducins are known to bind g protein betagamma subunits in vitro, and are postulated to regulate their signaling function in vivo. here we describe two homologues of phosducin in yeast, called plp1 and plp2. both gene products were cloned, expressed, and purified as glutathione s-transferase fusions. of the two isoforms, plp1 bound most preferentially to gbetagamma. binding was enhanced by pheromone stimulation and by the addition of gtpgammas, conditions that favor dissociation of g ...200010749875
cloning and characterization of the lipooligosaccharide galactosyltransferase ii gene of haemophilus ducreyi.haemophilus ducreyi is the etiologic agent of chancroid, a genital ulcer disease. the lipooligosaccharide (los) is considered to be a major virulence determinant and has been implicated in the adherence of h. ducreyi to keratinocytes. strain a77, an isolate from the paris collection, is serum sensitive, poorly adherent to fibroblasts, and deficient in microcolony formation. structural analysis indicates that the los of strain a77 lacks the galactose residue found in the n-acetyllactosamine porti ...200010735874
efficacy of an outer membrane protein of pasteurella haemolytica a2, a7 or a9-enriched vaccine against intratracheal challenge exposure in sheep.the outer membrane proteins (omp) were extracted from the p. haemolytica a2, a7 and a9 to determine their potential as immunogens and their capability for cross-protection. sixty lambs of approximately 9 months old were divided into four main groups. animals in group 1 were vaccinated with 2ml vaccine containing 100microg/ml of the outer membrane proteins of p. haemolytica a2. animals in group 2 were similarly vaccinated with the omps of p. haemolytica a7 while group 3 with omps of p. haemolytic ...200010731614
[in vitro activity of 12 antibiotics used in veterinary medicine against mannheimia haemolytica and pasteurella multocida isolated from calves in the netherlands].results of susceptibility tests of clinical isolates of animal pathogens are periodically summarized and reported by the animal health service. however, these results are based upon qualitative test methods. in the present paper results of quantitative susceptibility tests of twelve antibacterial agents against mannheimia haemolytica (mha) and pasteurella multocida (pmu) isolated from dutch calves in 1996 and 1997 are presented. minimum inhibitory concentrations of amoxicillin, ceftiofur, tetrac ...200010730339
role of platelet-activating factor in alveolar septal injury associated with experimentally induced pneumonic pasteurellosis in calves.to determine whether platelet-activating factor (paf) is involved in acute lung microvascular injury associated with pneumonic pasteurellosis in calves.200010714514
effects of il-12 on immune responses induced by transcutaneous immunization with antigens formulated in a novel lipid-based biphasic delivery system.the development of non-invasive methods for the delivery of proteins through the permeability barriers, such as the intact skin, will greatly facilitate the administration of human and veterinary vaccines. in the present study we used recombinant pasteurella haemolytica leukotoxin (lkt) and hen egg lysozyme (hel) as model antigens to investigate the ability of transdermal administration of vaccine antigens to induce humoral and cellular responses in mice and to assess the immunomodulatory effect ...200010699333
cell adhesion molecules in the pathogenesis of and host defence against microbial infection.eukaryotic cell adhesion molecules (cams) are used by various cells and extracellular molecules in host defence against infection. they are involved in many processes including recognition by circulating phagocytes of a site of inflammation, transmigration through the endothelial barrier, diapedesis through basement membrane and extracellular matrix, and release of effector mechanisms at the infected site. cams involved in leucocyte-endothelial cell interaction include the selectins, integrins, ...199910694943
the production and evaluation of pasteurella haemolytica leukotoxin in the supernatant of submerged cultures in fermenters.the optimal production of p. haemolytica leukotoxin in the culture supernatant of a fluid medium is dependent on a number of factors. the leukotoxin has to be produced by using a strain that is known for its ability to produce high quantities of leukotoxin, inoculated into the most suitable type of medium at the correct culture density containing the necessary supplements and harvested after a certain growth period. the volume in which it is produced may also have an influence. two different pro ...199910689699
development of an in vitro fluorometric assay to study adherence of pasteurella haemolytica to bovine cells.to develop an in vitro fluorometric assay to assess pasteurella haemolytica adherence to bovine respiratory and epithelial cells and compare adherence of single strains of p. haemolytica serovars a1 and a2 (pha1 and pha2, respectively).200010685682
ultrastructure of pasteurella haemolytica-induced changes in gnotobiotic calf lung.gnotobiotic calves born and maintained in a germ-free environment until inoculated with a pathogen are model animals for studying the progression of a specific disease, such as pneumonic pasteurellosis. to investigate early progression of pneumonic pasteurellosis, we compared the ultrastructure of regions of gas-exchange in the lungs of three challenge-exposed and three uninoculated control gnotobiotic calves. three calves were inoculated endobronchially with a bolus of 7.9 x 10(10) cfu of paste ...199910685387
effects of delivery method on serological responses of bighorn sheep to a multivalent pasteurella haemolytica supernatant vaccine.the safety and efficacy of a remotely delivered multivalent pasteurella haemolytica supernatant vaccine (serotypes a2 and t10) were examined in captive rocky, mountain bighorn sheep (ovis canadensis canadensis). twenty bighorn sheep were grouped according to baseline leukotoxin neutralizing antibody titers (< or =2 or >2 log2(-1)) and vaccination history (previously vaccinated or unvaccinated). within these groups, animals were randomly assigned to one of two delivery treatments: hand injection ...200010682747
vaccination of neonatal colostrum-deprived calves against pasteurella haemolytica a1.colostrum-deprived holstein calves were vaccinated at 2 and 4 wk of age with a pasteurella haemolytica a1 culture supernatant vaccine to determine whether active immune responses and protection could be induced in this age group in the absence of maternal antibodies. all calves responded to vaccination with high titers of igm antibodies to capsular polysaccharide within 1 wk of primary vaccination. mean titers of igg1 and igg2 antibodies to this antigen increased significantly by 2 wk after seco ...200010680649
immunogenicity of antigens in boiled alginate microspheres.vaccine efficacy can be enhanced by delivery of antigens in synthetic microspheres. the process of antigen incorporation into microspheres can expose fragile antigens to damaging conditions, such as high temperatures, and to bacterial contamination. maintenance of immunogenicity of several antigens and reduction of bacterial load in alginate microspheres following boiling was evaluated. mice were immunized subcutaneously, initially and again 21 days later, with either non-boiled or boiled micros ...200010680608
decreased apolipoprotein c-iii concentration in the high-density lipoprotein fraction from calves inoculated with pasteurella haemolytica and bovine herpes virus-1.lipoprotein lipid and apoprotein concentrations are known to be altered during the acute-phase response. we have previously shown that the serum activity of lecithin:cholesterol acyltransferase (lcat) and concentration of cholesteryl esters, both constituents of the high-density lipoprotein (hdl) fraction, are reduced in calves inoculated with pasteurella haemolytica and bovine herpes virus-1, the two major pathogens for calf pneumonia. the concentration of apolipoprotein c-iii (apoc-iii), a low ...200010676889
detection of annexins i and iv in bronchoalveolar lavage fluids from calves inoculated with bovine herpes virus-1.annexins are phospholipid-binding proteins and are abundant in the lung. annexins i and iv, but not ii and vi, have been detected in bronchoalveolar lavage (bal) fluids from calves inoculated with pasteurella haemolytica, the pathogen for calf pneumonia. in this study, bal fluids from calves with experimental pneumonia induced by inoculation to right lung lobes of bovine herpes virus-1 (bhv-1), the major viral pathogen for pneumonia, were examined for detection of annexins i and iv. of 6 calves ...200010676887
occurrence and structure-function relationship of pentameric short sequence repeats in microbial genomes.it is suggested that genomes found in any form of cellular life contain potentially size-variable repetitive dna moieties. in eukaryotes, large proportions of the multi-chromosomal genome consist of various classes of repetitive dna. also in archaeal genomes, repetitive dna is encountered and, as is the case for the eukaryotes as well, little or no function is at present attributable to most of it. for prokaryotes, elegant experiments have highlighted so-called slipped strand nucleotide mispairi ...199910673001
the effects of dexamethasone on the response of bronchus-associated lymphoid tissue to intranasal administration of formalin-killed pasteurella haemolytica a2 in goats.a trial was conducted to observe the immediate and chronic effects in goats of dexamethasone administration on the bronchus-associated lymphoid tissue (balt) response to intranasal administration of formalin-killed pasteurella haemolytica a2. twenty-four goats were divided into four groups. those in group 1 were injected intramuscularly with 1 mg/kg dexamethasone on three consecutive days, followed by intranasal exposure to formalin-killed p. haemolytica a2 one day after the last dexamethasone t ...199910672963
a stochastic partial-budget analysis of an experimental pasteurella haemolytica feedlot vaccine trial.a field trial compared a modified pasteurella haemolytica biotype a serotype 1 leukotoxin vaccine to a commercial vaccine during march-july 1995 in a natal midlands, south african, feedlot. weaners/long weaners purchased by the feedlot were allocated systematically into test vaccine and control vaccine groups of 1241 and 1240 head, respectively, and fed in groups of approximately 200 head. morbidity and mortality were monitored until the animals were marketed. details of pleuritis and pneumonia ...200010665949
evaluation of wzz/mpa1/mpa2 proteins based on the presence of coiled-coil regions. 200010658645
in vitro microbiological characterization of novel cyclic homopentapeptides, cp-101,680 and cp-163,234, for animal health use.two cyclic homopentapeptides, cp-101,680 and cp-163,234 [6a-(3',4'-dichlorophenylamino) analogs of viomycin and capreomycin, respectively], were identified as novel antibacterial agents for the treatment of animal disease, especially for livestock respiratory disease. the in vitro microbiological characterization of both cp-101,680 and cp-163,234 was carried out using their parent compounds, viomycin and capreomycin, as controls. this characterization included antibacterial spectrum, influence o ...199910656573
genomic structure of the rat major ap endonuclease gene (apex) with an adjacent putative o-sialoglycoprotease gene (prsmg1/gcpl1) and a processed apex pseudogene (apexp1).genomic sequencing and chromosomal assignment of the gene encoding rat apex nuclease, a multifunctional dna repair enzyme, were performed. an active apex gene and a processed pseudogene were isolated from a rat genomic library. the active apex gene consists of 5 exons and 4 introns spanning 2.1 kb. the putative promoter region of the apex gene lacks the typical tata box, but contains caat boxes and a cpg island having putative binding sites for several transcription factors, such as sp1, ap-2, g ...199910631378
ultrastructural characterization of apoptosis in bovine lymphocytes exposed to pasteurella haemolytica leukotoxin.to characterize ultrastructural changes of bovine lymphocytes exposed to pasteurella haemolytica leukotoxin (lkt).200010630778
comparison of pasteurella spp. simultaneously isolated from nasal and transtracheal swabs from cattle with clinical signs of bovine respiratory disease.twenty-four matched pairs of isolates of pasteurella haemolytica and three matched pairs of isolates of pasteurella multocida were isolated by using a nasal swab and a transtracheal swab from individual calves with clinical signs of bovine respiratory disease. the identity of each matched pair was confirmed biochemically and serologically. the similarity of the isolates obtained from a nasal swab and from a transtracheal swab was compared by using ribotyping and antibiotic susceptibility analyse ...200010618110
lymphocyte function-associated antigen 1 is a receptor for pasteurella haemolytica leukotoxin in bovine leukocytes.pasteurella (mannheimia) haemolytica leukotoxin (lkt) causes cell type- and species-specific effects in ruminant leukocytes. recent studies indicate that p. haemolytica lkt binds to bovine cd18, the common subunit of all beta2 integrins. we designed experiments with the following objectives: to identify which member of the beta2 integrins is a receptor for lkt; to determine whether lkt binding to the receptor is target cell (bovine leukocytes) specific; to define the relationships between lkt bi ...200010603370
studies on the respiratory disease 'sonbobe' in camels in the eastern lowlands of ethiopia.new epidemics of respiratory disease have caused 29.6 morbidity and 6.4% mortality in camels in the somalia region of ethiopia. the major clinical signs observed were fever of 40-41.5 degrees c, depression, cough, loss of appetite and a watery nasal discharge that became mucopurulent at a later stage. finally, the camel became recumbent and extended its neck straight along the ground. some of the animals died within 8-9 days. the major post-mortem lesions were hydrothorax, adhesion of the lung t ...199910599129
purification and characterization of an adhesin from pasteurella haemolytica.we purified an adhesin from pasteurella. haemolytica by affinity chromatography using glutaraldehyde treated rabbit erythrocytes stroma. the adhesin is a protein of 68 kda, as determined by sds-page, and the most abundant amino acids constituting this protein were gly, ser, glx, and ala, and low concentrations of cys, met, and tyr residues were also found. the n-terminal sequence of the adhesin is anevnvyiykqpyli. no carbohydrate residues were detected. the adhesin agglutinated rabbit erythrocyt ...200010570221
correlation of pasteurella haemolytica leukotoxin binding with susceptibility to intoxication of lymphoid cells from various species.pasteurella haemolytica, the causative agent of shipping fever pneumonia in cattle, produces a leukotoxin (lkt) which lyses ruminant leukocytes with high efficiency but is reputed to not affect leukocytes from nonruminant species. in this study, we tested the supposition that lkt binding correlates positively with susceptibility to intoxication of susceptible isolated bovine lymphocytes and lymphoma tissue culture cells (bl3 cells) and negatively with reputed nonsusceptible equine, porcine, and ...199910569736
use of a polymerase chain reaction method to detect the leukotoxin gene lkta in biogroup and biovariant isolates of pasteurella haemolytica and p trehalosi.to determine whether pasteurella haemolytica and p trehalosi isolates possess the structural gene for pasteurella leukotoxin lkta and whether beta-hemolytic activity of these isolates correlated with detection of the lkta gene.199910566816
detection of annexin i and iv and haptoglobin in bronchoalveolar lavage fluid from calves experimentally inoculated with pasteurella haemolytica.to determine whether annexins or haptoglobin could be detected in bronchoalveolar lavage (bal) fluid specimens obtained from calves experimentally inoculated with pasteurella haemolytica.199910566814
anionic antimicrobial peptide-lysozyme interactions in innate pulmonary immunity.the respiratory tract contains numerous antimicrobial factors necessary for normal innate pulmonary defense. although many of these molecules reside in airway surface liquid (asl) simultaneously, little information exists concerning antagonistic, additive, or synergistic interactions. since both cationic lysozyme and anionic antimicrobial peptides (ap) are found in high concentrations in asl, the purpose of this study was to assess any interaction that might affect antimicrobial activity. for th ...199910563404
reduced serum lecithin:cholesterol acyltransferase activity and cholesteryl ester concentration in calves experimentally inoculated with pasteurella haemolytica and bovine herpes virus-1.lecithin:cholesterol acyltransferase (lcat), the enzyme responsible for esterification of cholesterol in plasma, is reported to be implicated in the regulation of inflammation in laboratory animals. the purpose of the present study was to elucidate the possible relevance of lcat in the pathogenesis of calf pneumonia induced by inoculations of pasteurella haemolytica and bovine herpes virus-1 into the calf lung. serum lcat activity was significantly (p < 0.01) reduced in calves inoculated with pa ...199910563286
bacterial phylogenetic clusters revealed by genome structure.current bacterial taxonomy is mostly based on phenotypic criteria, which may yield misleading interpretations in classification and identification. as a result, bacteria not closely related may be grouped together as a genus or species. for pathogenic bacteria, incorrect classification or misidentification could be disastrous. there is therefore an urgent need for appropriate methodologies to classify bacteria according to phylogeny and corresponding new approaches that permit their rapid and ac ...199910542177
protective capacity of the pasteurella haemolytica transferrin-binding proteins tbpa and tbpb in cattle.the transferrin-binding proteins tbpa and tbpb from pasteurella haemolytica biotype a serotype 1 were tested for their ability to confer protection against experimental p. haemolytica infection when administered to calves in vaccine formulations containing one or both antigens. vaccine groups included tbpb (single immunization), tbpb (two immunizations), tbpa, tbpa+tbpb and a placebo. all animals that received tbpb had measurable antibody titres against the antigen at the time of challenge, whil ...199910502460
in situ expression of intercellular adhesion molecule-1 (icam-1) mrna in calves with acute pasteurella haemolytica pneumonia.the in situ expression of intercellular adhesion molecule-1 (icam-1) mrna in normal and pneumonic lung tissues of holstein calves with bovine leukocyte adhesion deficiency (blad) was compared with that of age-matched non-blad holstein calves by in situ hybridization. twenty-four holstein calves (both blad and non-blad) were randomly assigned to one of two experimental groups and inoculated intrabronchially with pasteurella haemolytica or pyrogen-free saline. lung tissues were collected and fixed ...199910490211
expression of inducible nitric oxide synthase in spontaneous bovine bronchopneumonia.the expression of inducible nitric oxide synthase (inos), major histocompatibility class ii molecules (mhc-ii), cd68, and the calcium-binding proteins s100a8 and s100a9 (also called mrp8 and mrp14, respectively) was assessed in lung tissues from cattle that succumbed to pneumonia. expression patterns of these markers were related to the types of lung lesion. inos expression was only observed in lungs infected with arcanobacterium pyogenes or pasteurella haemolytica but not in lungs from cattle w ...199910490207
the leukotoxin of pasteurella haemolytica binds to beta(2) integrins on bovine leukocytes.the putative receptor proteins of pasteurella haemolytica leukotoxin were isolated from bovine polymorphonuclear neutrophil lysate by affinity chromatography on a leukotoxin-specific monoclonal antibody column to which the leukotoxin was pre-bound. sds-page of the purified proteins showed four bands at 180 kda, 170 kda, 150 kda and 95 kda, in addition to the expected 102-kda leukotoxin band and a series of bands with molecular masses lower than 102 kda representing the disintegrated leukotoxin. ...199910481101
postantibiotic and physiological effects of tilmicosin, tylosin, and apramycin at subminimal and suprainhibitory concentrations on some swine and bovine respiratory tract pathogens.the antimicrobial activity of tilmicosin, tylosin, and apramycin on some important gram-negative swine and bovine pathogens namely, pasteurella multocida, pasteurella haemolytica, bordetella bronchiseptica, and actinobacillus pleuropneumoniae were studied in vitro. the effect of minimal inhibitory concentrations (mics) and sub-mics (1/4, 1/2 mic) on bacterial growth was evaluated. the presence of tilmicosin, tylosin and apramycin in the medium decreased the rate of growth of the bacterial strain ...199910461841
molecular cloning of the pasteurella haemolytica poma gene and identification of bovine antibodies against poma surface domains.the gene (poma) encoding poma, an ompa-like major outer membrane protein of the bovine respiratory pathogen pasteurella haemolytica, was cloned, and its nucleotide sequence was determined. the deduced amino acid sequence of poma has significant identity with the sequences of other ompa family proteins. absorption of three different bovine immune sera with whole p. haemolytica cells resulted in a reduction of bovine immunoglobulin g reactivity with recombinant poma in western immunoblots, suggest ...199910456961
use of tunel staining to detect apoptotic cells in the lungs of cattle experimentally infected with pasteurella haemolytica.lung sections taken from calves with experimental pasteurella haemolytica respiratory infection exhibited increased numbers of tunel positive cells with time after challenge. this finding suggests that p. haemolytica, or toxins and other components released by the organism, induces apoptosis in bovine leukocytes in vivo. by so doing this might impair host defense and contribute in part to the severe pneumonia that characterizes bovine pasteurellosis.199910455008
role of phospholipase d in pasteurella haemolytica leukotoxin-induced increase in phospholipase a(2) activity in bovine neutrophils.the effects of pasteurella haemolytica leukotoxin (lkt) on the activity of phospholipase d (pld) and the regulatory interaction between pld and phospholipase a(2) (pla(2)) were investigated in assays using isolated bovine neutrophils labeled with tritiated phospholipid substrates of the two enzymes. exposure of [(3)h]lysophosphatidylcholine-labeled neutrophils to lkt caused concentration- and time-dependent production of phosphatidic acid (pa), the product of pld. lkt-induced generation of pa wa ...199910417136
bovine cd18 identified as a species specific receptor for pasteurella haemolytica leukotoxin.ligand blotting of pasteurella haemolytica leukotoxin (lkt) susceptible bl3 bovine lymphoma cell membranes with lkt detected two putative receptors with mr of 95 and 100 kda, whereas no lkt binding to membrane proteins was detected for lkt non-susceptible human leukemic cells. anti-bovine cd18 and cd11a/cd18 mab recognized 95 and 100kda bands from bl3 cell membranes. cd18 isolated from bl3 cell membranes bound lkt. pre-incubation of bl3 cells with anti-bovine cd18 or cd11a/cd18 mab caused partia ...199910414364
conservation of expression and n-terminal sequences of the pasteurella haemolytica 31-kilodalton and pasteurella trehalosi 29-kilodalton periplasmic iron-regulated proteins.this study examined the conservation of expression of a 31-kda iron-regulated protein by serotypes of pasteurella haemolytica and pasteurella trehalosi associated with pasteurellosis of cattle and sheep. a polyclonal antibody prepared against the purified 31-kda periplasmic iron-regulated protein from p. haemolytica serotype a1 showed that all p. haemolytica serotypes expressed similar 31-kda proteins with identical n-terminal sequences, whereas p. trehalosi serotypes expressed immunologically d ...199910391874
serotypes of pasteurella haemolytica and pasteurella trehalosi isolated from farm animals in hungary.the biochemical and serological characteristics of 486 p. haemolytica and 31 p. trehalosi strains (517 in total) isolated from different lesions of cattle, sheep, goats, pigs and poultry were examined. a total of 476 p. haemolytica strains (97.9%) showed the characteristics typical of the former biotype a of p. haemolytica, while 10 isolates (2.1%), all from poultry, could not be biotyped. a total of 481 strains (93.0%) could be assigned to one of the 17 serotypes of p. haemolytica-p. trehalosi ...199910379234
serotypes and electrophoretic protein profiles of pasteurella haemolytica isolated from pneumonic ovine lungs.serotypes and sds-page protein profiles of p. haemolytica isolated from pneumonic ovine lungs were investigated. of 268 p. haemolytica isolates, 232 (86.6%) were serotypable. a total of 12 serotypes were recognized in 20 different geographic origins of central turkey. the most common serotype was a2, followed by a7, a1 and t4. serotypes a13, a14, a16 and t15 could not be detected. in sds-page, marked differences between major bands of biotype a and t strains were found. in numerical analysis of ...199910379102
cloning and characterization of the gene encoding pasteurella haemolytica fnrp, a regulator of the escherichia coli silent hemolysin shea.a pasteurella haemolytica a1 gene was identified from a recombinant library clone that expressed hemolysis in host escherichia coli cells. the gene, designated fnrp, had sequence identity to e. coli fnr, a global transcriptional regulator of genes required for conversion to anaerobic growth. fnrp complemented anaerobic deficiencies of a fnr-null mutant strain of e. coli and increased expression of the fnr-dependent, anaerobic terminal reductase gene, frda. fnrp was purified, identified by immuno ...199910368164
cytokine profiles following interaction between bovine alveolar macrophages and pasteurella haemolytica.pasteurella haemolytica is a gram negative bacterium frequently isolated from the lungs of calves suffering from a fibrinous pneumonic condition known as shipping fever. to understand the pathogenesis of this disease, we investigated the induction of cytokin gene expression in cultures of bovine alveolar macrophages (bam) stimulated with heat-killed p. haemolytica. northern blot analysis of total rna showed that p. haemolytica induced early, abundant, and consistent synthesis of il-1, tnf-alpha, ...199910343061
lipopolysaccharide complexes with pasteurella haemolytica leukotoxin.the presence of lipopolysaccharide (lps) in gram-negative bacterial repeats-in-toxin (rtx) toxin preparations, as well as the harsh conditions required to remove it, suggests that lps may complex with rtx toxins. concentrated culture supernatant (ccs) preparations of the rtx toxin pasteurella haemolytica leukotoxin (lkt) contained lkt and lps as the most prominent components, with lkt and lps constituting approximately 30 and 50% of the density of the silver-stained fraction on sodium dodecyl su ...199910338500
clinical and microbiological study of an otitis media outbreak in calves in a dairy herd.on a dairy farm, otitis media was diagnosed in 64 suckler calves (21.8%) during a study period of 2 years, and in 10 calves (3.4%) in the third year. the inflammation was unilateral in 63 and bilateral in 11 calves. the affected calves were dull, lacked appetite, were pyrexic and displayed drooping ear or ears and tilted heads with purulent discharge exuding from the external ear canal. of the affected animals, 56 (87.5%) were aged between 3 and 8 weeks. morbidity was higher during the calving s ...199910337235
critica: coding region identification tool invoking comparative analysis.gene recognition is essential to understanding existing and future dna sequence data. critica (coding region identification tool invoking comparative analysis) is a suite of programs for identifying likely protein-coding sequences in dna by combining comparative analysis of dna sequences with more common noncomparative methods. in the comparative component of the analysis, regions of dna are aligned with related sequences from the dna databases; if the translation of the aligned sequences has gr ...199910331277
immunologic responses of domestic and bighorn sheep to a multivalent pasteurella haemolytica vaccine.the efficacy of a pasteurella haemolytica vaccine (serotypes a1, a2, and t10) to induce humoral antibodies and alter colonization of the upper respiratory tract by related p. haemolytica spp. strains was evaluated in 10 bighorn (ovis canadensis canadensis) and 10 domestic (ovis aries) sheep. sheep of each species were divided into five pairs based on age and history of respiratory disease. one sheep in each pair was vaccinated twice 2 wk apart with 2 ml of vaccine (vac group) and the remaining a ...199910231755
adjuvant and protective properties of native and recombinant bordetella pertussis adenylate cyclase toxin preparations in mice.bordetella pertussis produces a cell-invasive adenylate cyclase toxin which is synthesised from the cyaa gene as an inactive protoxin that is post-translationally activated by the product of the cyac gene. purified active and inactive cyaa proteins were prepared from b. pertussis or from recombinant escherichia coli expressing both cyaa and cyac genes or the cyaa gene alone. respectively. in addition, a hybrid toxin (hyb2) in which an internal region of cyaa had been replaced with the analogous ...199910225286
investigations on the species specificity of mannheimia (pasteurella) haemolytica serotyping.eleven serotypes (1, 2, 5-9, 12-14 and 16) have been demonstrated within mannheimia haemolytica. subsequent serotyping of 166 mannheimia haemolytica-like strains, genetically and phenotyphically distinct from mannheimia haemolytica, and isolated from ruminants, pigs, hares and rabbits showed that 13.2% were typeable, 19 of which were serotype 11 representing strains now being classified as m. glucosida. in addition, three strains belonged to serotypes 6, 9 and 16, respectively. additionally, the ...199910223327
pasteurella haemolytica leukotoxin and endotoxin induced cytokine gene expression in bovine alveolar macrophages requires nf-kappab activation and calcium elevation.in bovine alveolar macrophages (bams), exposure to leukotoxin (lkt) and endotoxin (lps) from pasteurella haemolytica results in expression of inflammatory cytokine genes and intracellular calcium ([ca2+]i) elevation. leukotoxin from p. haemolytica interacts only with leukocytes and platelets from ruminant species. upregulation of cytokine genes in different cells by lps involves activation of the transcription factor nf-kappab (nf-kappab), resulting in its translocation from the cytoplasm to the ...199910222211
ceftiofur distribution in plasma and joint fluid following regional limb injection in cattle.the objective of this study was to evaluate the efficacy of regional intravenous (i.v.) injection of ceftiofur in delivery of this drug to joint fluid and plasma in a limb distal to a tourniquet in five, healthy, adult, mixed breed beef cattle. a tourniquet was positioned in the mid-metacarpal region, and 500 mg of ceftiofur was administered through a catheter in the dorsal common digital vein (dcdv). plasma samples were collected from the catheter at 15, 30 and 45 min postinjection, and from th ...199910211712
cellular and humoral responses in the respiratory tract of goats following intranasal stimulation using formalin-killed pasteurella haemolytica a2.a study to determine the immunoglobulin and cellular responses in the respiratory tract of goats following intranasal exposures to formalin-killed pasteurella haemolytica a2 was carried out. forty-two goats were divided into two groups. goats in group 1 were subjected to double intranasal exposures to formalin-killed p. haemolytica a2 while goats in group 2 were the unexposed control. prior to and at weekly intervals post-exposure, three goats from each group were killed, serum samples were coll ...199910189198
identification of immunogenic, surface-exposed outer membrane proteins of pasteurella haemolytica serotype 1.pasteurella haemolytica serotype 1 (s1) is the bacterium most frequently recovered from the lungs of cattle that have succumbed to shipping fever pneumonia. p. haemolytica outer membrane proteins (omps) are important immunogens in the development of resistance to pneumonic pasteurellosis. the purpose of this study was to identify the repertoire of immunogenic, surface-exposed p. haemolytica (s1) omps, that could be important in the development of protective immunity. we determined surface exposu ...199910189196
role of intracellular calcium in pasteurella haemolytica leukotoxin-induced bovine neutrophil leukotriene b4 production and plasma membrane damage.isolated neutrophils were used to study the intracellular calcium ([ca2+]i) dependency of pasteurella haemolytica leukotoxin-induced production of leukotriene b4 and plasma membrane damage. exposure of neutrophils to leukotoxin caused a rapid and concentration-dependent increase in [ca2+]i, followed by simultaneous plasma membrane damage and production of leukotriene b4. removal of extracellular ca2+, replacement of ca2+ with other divalent cations, or exposure to high concentration of verapamil ...199910188239
regulation of capsular polysialic acid biosynthesis by temperature in pasteurella haemolytica a2.the capsular polysaccharide of pasteurella haemolytica a2 consists of a linear polymer of n-acetylneuraminic acid (neu5ac) with alpha(2-8) linkages. the production of this polymer is strictly regulated by the growth temperature and above 40 degrees c no production is detected. analysis of the enzymatic activities directly involved in its biosynthesis reveals that neu5ac lyase, cmp-neu5ac synthetase and polysialyltransferase are involved in this regulation. very low activities were found in p. ha ...199910094482
evidence of pasteurella haemolytica linked immune complex disease in natural and experimental models.the pathogenesis of bovine pneumonic pasteurellosis is not completely understood, and studies have not established that pasteurella haemolytica a1 (ph1) virulence is exclusively responsible for the development of acute pulmonary lesions. the purpose of this investigation was to determine if immune complex disease is involved in the pathogenesis of bovine pneumonic pasteurellosis. a retrospective immunohistologic study of lung tissue from natural cases of bovine pneumonic pasteurellosis (44) as p ...199910089159
efficacy of sustained release needle-less ceftiofur sodium implants in treating calves with bovine respiratory disease.three experiments were conducted to determine preliminary efficacy of sustained release needle-less implants in effecting cure in calves with bovine respiratory disease. one hundred and twenty beef calves with a rectal temperature > or = 40 degrees c and shallow or labored respiration and coughing were used in these experiments. four groups (1-ceftiofur sodium injections [days 1, 2, and 3], 2-ceftiofur sodium needle-less implants [days 1, 2, and 3], 3-ceftiofur sodium needle-less implants [days ...199910085771
[investigation of outer membrane proteins of pasteurella. 2: iron-regulated outer membrane proteins of pasteurella multocida and pasteurella haemolytica].pasteurella multocida and pasteurella haemolytica produce specific proteins in the outer membrane under iron-depleted conditions. pasteurella multocida serovar a expresses these proteins of molecular masses of 76 and 96 kda as determined by electrophoresis. the analogous serovar d produces a further iron-regulated protein of 85 kda. the pasteurella haemolytica strains of serovar a1, a6 and t contain iron-regulated outer membrane proteins of molecular masses of 71, 77 and 100 kda. these proteins ...199710084945
[long-chain fatty acids of pasteurella multocida nad pasteurella haemolytica].the relative contents of long-chain fatty acids in p. multocida and p. haemolytica were investigated. a dependence on the composition of the broth was established. accordingly, comparative quantitative studies on fatty acid contents have to be conducted using bacteria grown with the same lot of broth medium. as for p. multocida, there were significant differences between the serovars (c14 in tdhm and c16, delta 2c18 in bpl). these differences are, however, not significant to replace serotyping. ...199710084940
detection of haptoglobin in the high-density lipoprotein and the very high-density lipoprotein fractions from sera of calves with experimental pneumonia and cows with naturally occurring fatty liver.in addition to the lipoprotein-deficient d > 1.25 fraction, haptoglobin was detected in the high-density lipoprotein (hdl) and the very high-density lipoprotein (vhdl) fractions from sera of calves with experimental pneumonia and cows with naturally occurring fatty liver. it was not found in the chylomicrons, very low-density lipoprotein and low-density lipoprotein fractions. washing of the hdl fraction did not decrease the haptoglobin concentration. transferrin and immunoglobulin g were immunob ...199910081748
pasteurella haemolytica leukotoxin induced apoptosis of bovine lymphocytes involves dna fragmentation.it has been reported that pasteurella haemolytica leukotoxin (lkt) induces morphologic changes in bovine leukocytes consistent with apoptosis in vitro, but dna fragmentation was not observed. we investigated whether bovine lymphocytes undergo dna fragmentation during lkt-induced apoptosis. bovine peripheral blood lymphocytes were isolated by density gradient centrifugation and exposed to lkt or inactive pro-lkt protein from a lktc- mutant strain. after exposure, dna fragmentation in lymphocytes ...199910078599
primary and anamnestic responses of bovine bronchoalveolar and peripheral blood lymphocyte subsets to aerosolized pasteurella haemolytica a1.site-specific responses of bronchoalveolar and peripheral blood lymphocyte subsets were compared during primary and anamnestic immune responses against live pasteurella haemolytica a1 (ph1). eight 1-year old calves were sequentially exposed intrabronchially with aerosolized ph1 on days 0, 14, and 21, and two calves were sham exposed. bronchoalveolar and peripheral blood lymphocytes were analyzed before each ph1 exposure, and on days 3 and 7 post exposure using single and two-color flow cytometry ...199910077422
actin polymerization enhances pasteurella haemolytica leukotoxicity.pasteurella haemolytica leukotoxin is cytotoxic to bovine leukocytes, causing increased cell membrane permeability, osmotic swelling, release of cytosolic proteins and cell lysis. these studies were designed to test if leukotoxin causes release of the cytoskeletal protein, actin, from bovine leukemia cells and if purified actin-influenced bacterial growth or leukotoxin production. culture supernatants caused a 7-fold decrease in viability of bovine leukemia cells and increased cell permeability ...199910063536
biochemical conditions for the production of polysialic acid by pasteurella haemolytica a2.the capsular polysaccharide of pasteurella haemolytica a2 consists of a linear polymer of n-acetylneuraminic acid (neu5ac) with alpha(2-8) linkages. when the bacterium was grown at 37 degrees c for 90 h in 250 ml shake flasks at 200 rpm in brain heart infusion broth (bhib), it accumulated, attaining a level of 60 microg/ml. release of this polymer was strictly regulated by the growth temperature, and above 40 degrees no production was detected. the pathway for the biosynthesis of this sialic aci ...199810052589
characterization of a cacag pentanucleotide repeat in pasteurella haemolytica and its possible role in modulation of a novel type iii restriction-modification system.in a previous study, a recombinant plasmid that contains a cacag pentanucleotide repeat was isolated from a pasteurella haemolytica a1 library. southern hybridization analysis using a (cacag)5probe indicated the presence of two loci that contain the pentanucleotide repeats on the genome of p.haemolytica a1. additional hybridization analyses against genomic dna from related microorganisms indicated that the repeats are only present in p.haemolytica and pasteurella trehalosi t3. the various seroty ...199910037813
taxonomic relationships of the [pasteurella] haemolytica complex as evaluated by dna-dna hybridizations and 16s rrna sequencing with proposal of mannheimia haemolytica gen. nov., comb. nov., mannheimia granulomatis comb. nov., mannheimia glucosida sp. nov., mannheimia ruminalis sp. nov. and mannheimia varigena sp. nov.the present paper presents the conclusions of a polyphasic investigation of the taxonomy of the trehalose-negative [pasteurella] haemolytica complex. clusters previously identified by ribotyping and multilocus enzyme electrophoresis (mee) have been evaluated by 16s rrna sequencing and dna-dna hybridizations. results obtained by the different techniques were highly related and indicated that the [p.] haemolytica complex contains distinct genetic and phenotypic groups. at least seven species were ...199910028248
problems of identification in clinical microbiology exemplified by pig bite wound infections.our experience from attempts to identify bacteria isolated from boar bite/gore wounds is the background for a discussion of identification problems. some organisms, although not very common or well-known, can be identified when using commercial kits or conventional methods, provided they are sufficiently characterized, as exemplified by pasteurella aerogenes isolated from cases 1 and 2. some organisms may be wrongly identified, or not identified, by both commercial kits and conventional methods, ...19989987187
seroepidemiology of undifferentiated fever in feedlot calves in western canada.the relationships between 4 bacterial and 3 viral antibody titers and morbidity (undifferentiated fever (uf)) and mortality were investigated in recently weaned beef calves. blood samples from 100 animals that required treatment for uf (cases) and 100 healthy control animals (controls) were obtained: upon arrival at the feedlot (arrival), at the time of selection as a case or control (selection), and at approximately 33 d of the feeding period (convalescent). seroconversion to pasteurella haemol ...19999919366
mast cells of the bovine trachea: staining characteristics, dispersion techniques and response to secretagogues.sections of the lower trachea of cattle, fixed in either carnoy's or formalin, were stained with toluidine blue, alcian blue, or alcian blue and safranin o to study the mast cell population. after toluidine blue staining, about twice as many cells in tissue fixed in carnoy's contained dark blue granules compared with tissue fixed in formalin. in addition, for the first time in cattle, a population of cells containing red granules was identified after staining with alcian blue and safranin o. mos ...19999918327
induction of cd18-mediated passage of neutrophils by pasteurella haemolytica in pulmonary bronchi and bronchioles.pasteurella haemolytica is an important respiratory pathogen of cattle that incites extensive infiltrates of neutrophils into the lung. in addition to the parenchymal damage caused by factors released by p. haemolytica, neutrophils contribute to the pathologic changes in the lungs. molecules which mediate neutrophil infiltration into the lungs during p. haemolytica pneumonia are poorly characterized. to determine whether the cd18 family (beta2-integrin) of leukocyte adhesion molecules mediates i ...19999916073
molecular and biochemical mechanisms of pasteurella haemolytica leukotoxin-induced cell death.pasteurella haemolytica leukotoxin (lkt) is a member of the rtx family of pore-forming toxins that kill bovine immune cells. several studies have suggested that rtx toxins kill target cells by the induction of apoptosis. in the present study, bl3 bovine leukaemia cells were exposed to lkt and assessed by molecular and flow cytometric techniques that measure different aspects of apoptotic cell death. the intoxicated cells demonstrated morphological, light scatter and hoechst 33258 staining charac ...19989895270
pulsed-field gel electrophoresis is more efficient than ribotyping and random amplified polymorphic dna analysis in discrimination of pasteurella haemolytica strains.one hundred thirty-three strains of pasteurella haemolytica of both biotypes (90 and 43 strains of biotypes a and t, respectively) and almost all the serotypes were subjected to ribotyping, random amplified polymorphic dna (rapd) analysis, and pulsed-field gel electrophoresis (pfge) analysis for epidemiological purposes. a total of 15 patterns recorded as ribotypes ha to ho were found for the p. haemolytica biotype a strains, with ribotypes ha, hc, and hd being encountered most often (66 strains ...19999889223
the pasteurella haemolytica 35 kda iron-regulated protein is an fbpa homologue.in a previous investigation, a 35 kda iron-regulated protein was identified from total cellular proteins of pasteurella haemolytica grown under iron-depleted conditions. this study reports identification of the gene (fbpa) encoding the 35 kda protein based on complementation of an enta escherichia coli strain transformed with a plasmid derived from a p. haemolytica lambda zap ii library. cross-reactivity was demonstrated between an anti-35 kda mab and a 35 kda protein expressed in this strain. f ...19989884235
[resistance of bovine and porcine pasteurella to florfenicol and other antibiotics].the resistance pattern of 221 (89 bovine, 132 porcine) pasteurella strains isolated in 1996 against 16 antibiotics or chemotherapeutics was determined by agar diffusion. pasteurella haemolytica showed a higher level of resistance compared to pasteurella multocida; porcine strains were more resistant than bovine strains. over 90% of porcine pasteurella multocida were sensible to penicillin g, ampicillin, cephalothin, polymyxin b, enrofloxacin, chloramphenicol and florfenicol. in addition, bovine ...19989880937
target cell specificity of the pasteurella haemolytica leukotoxin is unaffected by the nature of the fatty-acyl group used to activate the toxin in vitro.the leukotoxin (lkta) of pasteurella haemolytica is active only against cells of ruminant origin. it is synthesised as an inactive protoxin encoded by the lkta gene and post-translationally modified to the active toxin by the product of the lktc gene. the lkta and lktc proteins were expressed separately in escherichia coli and partially purified. active lkta was produced in vitro in the presence of lktc and acyl-acyl carrier protein (acp) charged separately in vitro with a fatty-acyl group. the ...19989851045
genetic and immunologic analyses of plpe, a lipoprotein important in complement-mediated killing of pasteurella haemolytica serotype 1.pasteurella haemolytica serotype 1 is the bacterium most commonly associated with bovine shipping fever. the presence of antibodies against p. haemolytica outer membrane proteins (omps) correlates statistically with resistance to experimental p. haemolytica challenge in cattle. until now, specific p. haemolytica omps which elicit antibodies that function in host defense mechanisms have not been identified. in this study, we have cloned and sequenced the gene encoding one such protein, plpe. anal ...19989826333
discrimination between apo and iron-loaded forms of transferrin by transferrin binding protein b and its n-terminal subfragment.many pathogens of the pasteurellaceae and neisseriaceae possess a surface receptor that binds transferrin (tf) as an initial step in an iron acquisition process. this receptor is comprised of two proteins, transferrin binding protein a (tbpa) and transferrin binding protein b (tbpb). since the ability to recognize the iron-loaded form of tf preferentially would be a useful attribute of these receptors, we examined this property in a number of bacterial species. in solid-phase binding assays with ...19989817820
the association of titers to haemophilus somnus, and other putative pathogens, with the occurrence of bovine respiratory disease and weight gain in feedlot calves.serum samples were obtained from 602 calves (from 19 groups in four feedlots: three in ontario, and one in alberta) upon arrival at the feedlot and 28 d later. of these calves, 202 developed bovine respiratory disease (brd) and 400 did not develop brd. based on high antibody titers noted upon arrival, we infer that most calves were exposed to haemophilus somnus prior to arrival at the feedlot. within a group, calves with high titers on arrival had a reduced risk of developing brd later. most cal ...19989798091
serologic responses of young colostrum fed dairy calves to antigens of pasteurella haemolytica a1.the potential and limitations of early calfhood vaccination to induce active immunity to pasteurella haemolytica a1 in conventional colostrum fed calves were investigated. holstein dairy calves (n = 29) were vaccinated at 2 and 4 weeks of age, or at 6 and 8 weeks of age with a commercial culture supernatant vaccine (presponse, langford inc., guelph, ont., canada), or remained unvaccinated as controls. serum antibody titres were measured using an indirect bacterial agglutination assay, a leukotox ...19989796059
duration of serum antibody responses following vaccination and revaccination of cattle with non-living commercial pasteurella haemolytica vaccines.this study was designed to determine the duration of serum antibody responses to pasteurella haemolytica whole cells (wc) and leukotoxin (lkt) in weanling beef cattle vaccinated with various non-living p. haemolytica vaccines. serum antibodies to p. haemolytica antigens were determined periodically through day 140 by enzyme-linked immunosorbent assays. at day 140, cattle were revaccinated, and antibody responses periodically determined through day 196. three vaccines were used in two experiments ...19989796051
pneumonic pasteurellosis associated with pasteurella hemolytica serotype a6 in american bison (bison bison). 19989786525
characterization of a pasteurella haemolytica a1 mutant deficient in production of three membrane lipoproteins.to determine whether a pasteurella haemolytica a1 mutant that is unable to produce membrane lipoproteins has reduced susceptibility to complement-mediated killing, and to characterize the mutant strain.19989781461
bacterial croup caused by pasteurella haemolytica.we report a case of bacterial croup caused by pasteurella haemolytica. a nine-month-old girl was admitted to our hospital because of abrupt onset dyspnea and unconsciousness. from clinical and laboratory findings, she was diagnosed as having bacterial croup. pasteurella haemolytica was recovered from her tracheal secretion on admission. to our knowledge, this is the first report of bacterial croup caused by p. haemolytica.19989745781
the clinical efficacy of enrofloxacin in the treatment of experimental bovine pneumonic pasteurellosis.the clinical efficacy of enrofloxacin was tested in calves with experimentally induced pneumonic pasteurellosis. a strain of pasteurella haemolytica, biotype a, serotype 1 (p. haemolytica a1), which had been isolated from an outbreak of pneumonic pasteurellosis in feedlot calves, was used to induce the disease in 24 eight-month-old calves. each animal received, by intratracheal injection, 6 x 10(11) colony forming units of p. haemolytica a1 in a four-hour log phase culture. twelve similar animal ...19989741054
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