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comparative analysis of multiple inducible phages from mannheimia haemolytica.mannheimia haemolytica is a commensal bacterium that resides in the upper respiratory tract of cattle that can play a role in bovine respiratory disease. prophages are common in the m. haemolytica genome and contribute significantly to host diversity. the objective of this research was to undertake comparative genomic analysis of phages induced from strains of m. haemolytica serotype a1 (535a and 2256a), a2 (587a and 1127a) and a6 (1152a and 3927a).201526318735
characterization of mannheimia haemolytica in beef calves via nasopharyngeal culture and pulsed-field gel electrophoresis.mannheimia haemolytica is a major bacterial component of bovine respiratory disease (brd); unfortunately, very little is known about m. haemolytica transmission dynamics among cattle. identifying potential variation in m. haemolytica populations over time and induction of nasopharyngeal colonization and subsequent shedding are 2 areas where knowledge is lacking. in our study, 2 separate loads of 20 mixed-origin, male calves were purchased through an order buyer on different dates. deep nasophary ...201526330399
non-haemolytic mannheimia haemolytica as a cause of pleuropneumonia and septicemia in a calf.pure cultures of non-haemolytic mannheimia haemolytica, were cultivated from pleural effusion fluid and blood from a 1-month old belgian blue bull calf that was presented with apathy and anorexia. the isolates were identified as m. haemolytica by 16s rrna gene sequencing and maldi-tof-ms. since haemolysis on blood agar plates is considered a hallmark of m. haemolytica we wanted to elucidate the unusual phenotype of the isolated strain. therefore the leukotoxin operon (lktcabd), responsible for t ...201526344042
a literature review of antimicrobial resistance in pathogens associated with bovine respiratory disease.the objective of this paper was to perform a critical review of the literature as it pertains to the current status of antimicrobial resistance in pathogens associated with bovine respiratory disease (brd) in beef cattle and to provide a concise yet informative narrative on the most relevant publications available. as such, the scientific literature contained in pubmed, agricola, and cab were searched in february of 2014 for articles related to susceptibility testing of mannheimia haemolytica, p ...201526373635
bactericidal effects of various concentrations of enrofloxacin, florfenicol, tilmicosin phosphate, and tulathromycin on clinical isolates of mannheimia haemolytica.to determine bactericidal effects of enrofloxacin, florfenicol, tilmicosin, and tulathromycin on clinical isolates of mannheimia haemolytica at various bacterial densities and drug concentrations.201526413823
identification of immunodominant proteins from mannheimia haemolytica and histophilus somni by an immunoproteomic approach.mannheimia haemolytica and histophilus somni are frequently isolated from diseased cattle with bovine respiratory disease (brd). they compromise animal lung function and the immune responses generated are not sufficient to limit infection. identification of specific immunogenic antigens for vaccine development represents a great challenge. immunogenic proteins were identified by immunoproteomic approach with sera from cattle immunized with a commercial cellular vaccine of m. haemolytica and h. s ...201526424916
bacterial species-specific activity of a fluoroquinolone against two closely related pasteurellaceae with similar mics: differential in vitro inoculum effects and in vivo efficacies.we investigated the antimicrobial activity of a fluoroquinolone against two genetically close bacterial species belonging to the pasteurellaceae family. time-kill experiments were used to measure the in vitro activity of marbofloxacin against two strains of mannheimia haemolytica and pasteurella multocida with similar mics. we observed that marbofloxacin was equally potent against 105 cfu/ml inocula m. haemolytica and p. multocida. however, an inoculum effect was observed with p. multocida, mean ...201526506096
the upper respiratory tract is a natural reservoir of haemolytic mannheimia species associated with ovine mastitis.lamb suckling has been suggested to be an important way of infecting a ewe's udder with different bacteria, including mannheimia haemolytica. to test the potential role of lambs in transferring mannheimia species to the ewe's udder, the restriction endonuclease cleavage patterns of isolates obtained from nasopharyngeal swabs were compared with those obtained from cases of mastitis. sterile cotton swabs were used to collect nasopharyngeal samples from 50 ewes and 36 lambs from three flocks. m. ha ...201526542125
single pathogen challenge with agents of the bovine respiratory disease complex.bovine respiratory disease complex (brdc) is an important cause of mortality and morbidity in cattle; costing the dairy and beef industries millions of dollars annually, despite the use of vaccines and antibiotics. brdc is caused by one or more of several viruses (bovine respiratory syncytial virus, bovine herpes type 1 also known as infectious bovine rhinotracheitis, and bovine viral diarrhea virus), which predispose animals to infection with one or more bacteria. these include: pasteurella mul ...201526571015
comparison of mannheimia haemolytica isolates from an outbreak of bovine respiratory disease.the objective of this study was to determine the clonal relatedness of mannheimia haemolytica isolates responsible for an outbreak of bovine respiratory disease in a commercial feedlot. the isolates were obtained from the lungs of 21 calves with fatal pneumonia that were part of a group of 206 total calves. all isolates were serotyped and analyzed by pulsed-field gel electrophoresis (pfge) and for antibiotic sensitivity patterns. elisa and immunoblotting assays were performed to compare serum an ...201626711032
histophilosis as a natural disease.histophilus somni is responsible for sporadic disease worldwide in cattle and, to a lesser extent, in small ruminants, bighorn sheep (ovis canadensis), and north american bison (bison bison). the importance of h. somni diseases can be attributed to improved clinical and laboratory recognition, combined with the growth in intensive management practices for cattle. although outbreaks of bovine histophilosis can occur year-round, in northern and southern hemispheres, it is most frequent in late fal ...201626847357
one year duration of immunity of the modified live bovine viral diarrhea virus type 1 and type 2 and bovine herpesvirus-1 fractions of vista® once sq vaccine.three studies were performed to determine the duration of immunity of the bovine viral diarrhea virus type 1 and type 2 (bvdv-1 and bvdv-2) and bovine herpesvirus-1 (bhv-1) fractions of a commercially prepared modified-live vaccine. vista® once sq (vista®) vaccine contains five modified-live viruses, bvdv-1, bvdv-2, bhv-1, bovine respiratory syncytial virus, and bovine parainfluenza 3 virus, and two modified-live bacteria, pasteurella multocida and mannheimia haemolytica. for all three studies, ...201626859238
comparison of active drug concentrations in the pulmonary epithelial lining fluid and interstitial fluid of calves injected with enrofloxacin, florfenicol, ceftiofur, or tulathromycin.bacterial pneumonia is the most common reason for parenteral antimicrobial administration to beef cattle in the united states. yet there is little information describing the antimicrobial concentrations at the site of action. the objective of this study was to compare the active drug concentrations in the pulmonary epithelial lining fluid and interstitial fluid of four antimicrobials commonly used in cattle. after injection, plasma, interstitial fluid, and pulmonary epithelial lining fluid conce ...201626872361
comparative genomic analysis of mannheimia haemolytica from bovine sources.bovine respiratory disease is a common health problem in beef production. the primary bacterial agent involved, mannheimia haemolytica, is a target for antimicrobial therapy and at risk for associated antimicrobial resistance development. the role of m. haemolytica in pathogenesis is linked to serotype with serotypes 1 (s1) and 6 (s6) isolated from pneumonic lesions and serotype 2 (s2) found in the upper respiratory tract of healthy animals. here, we sequenced the genomes of 11 strains of m. hae ...201626926339
bovine gamma delta t cells contribute to exacerbated il-17 production in response to co-infection with bovine rsv and mannheimia haemolytica.human respiratory syncytial virus (hrsv) is a leading cause of severe lower respiratory tract infection in children under five years of age. il-17 and th17 responses are increased in children infected with hrsv and have been implicated in both protective and pathogenic roles during infection. bovine rsv (brsv) is genetically closely related to hrsv and is a leading cause of severe respiratory infections in young cattle. while brsv infection in the calf parallels many aspects of human infection w ...201626942409
molecular versus conventional culture for detection of respiratory bacterial pathogens in poultry.acute respiratory tract infections are leading causes of morbidity in poultry farms allover the world. six pathogens; escherichia coli, mycoplasma gallisepticum, staphylococcus aureus, pasteurella multocida, mannheimia haemolytica and pseudomonas aeruginosa were involved in respiratory infections in poultry. herein, conventional identification procedures and polymerase chain reaction (pcr) were applied for detection of the most common respiratory bacterial pathogens in clinical specimens of poul ...201626950451
impact of timing and dosage of a fluoroquinolone treatment on the microbiological, pathological, and clinical outcomes of calves challenged with mannheimia haemolytica.the efficacy of an early and low inoculum-adjusted marbofloxacin treatment was evaluated on microbiological and clinical outcomes in calves infected with 4.10(7) cfu of mannheimia haemolytica a1. twenty-two calves were included based on their rectal temperature rise in the 10 h after challenge and allocated in four groups, receiving a single intramuscular injection of saline (con), 2 mg/kg marbofloxacin 2-4 h after inclusion (early treatment, e2), 2 or 10 mg/kg marbofloxacin 35-39 h after inclus ...201626973615
rapid detection of mannheimia haemolytica in lung tissues of sheep and from bacterial culture.this study was aimed to detect mannheimia haemolytica in lung tissues of sheep and from a bacterial culture.201527047201
associations between prior management of cattle and risk of bovine respiratory disease in feedlot cattle.bovine respiratory disease (brd) is the major cause of clinical disease and death in feedlot populations worldwide. a longitudinal study was conducted to assess associations between risk factors related to on-farm management prior to transport to the feedlot and risk of brd in a population of feedlot beef cattle sourced from throughout the cattle producing regions of australia. exposure variables were derived from questionnaire data provided by farmers supplying cattle (n=10,721) that were a sub ...201627094138
monitoring of antimicrobial susceptibility of respiratory tract pathogens isolated from diseased cattle and pigs across europe, 2009-2012: vetpath results.vetpath is an ongoing pan-european antibiotic susceptibility monitoring programme that collects pathogens from diseased cattle, pigs and poultry. in the current study, 996 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 10 countries during 2009-2012. pasteurella multocida, mannheimia haemolytica and histophilus somni fro ...201627102206
the use of maldi-tof mass spectrometry for rapid identification of mannheimia haemolytica.mannheimia haemolytica is the most important bacterial pathogen isolated from cases of bovine respiratory disease (brd). routine identification of these bacteria is usually performed using phenotypic methods. our study showed that maldi-tof ms is a reliable alternative to these methods. all of the strains analyzed were identified as m. haemolytica. the identification results were compared to those obtained using conventional methods commonly used in microbiological diagnostics, based on detectio ...201627109070
fusobacterium necrophorum in north american bighorn sheep ( ovis canadensis ) pneumonia.fusobacterium necrophorum has been detected in pneumonic bighorn sheep (bhs; ovis canadensis ) lungs, in addition to the aerobic respiratory pathogens mannheimia haemolytica , bibersteinia trehalosi , pasteurella multocida , and mycoplasma ovipneumoniae . similar to m. haemolytica , f. necrophorum produces a leukotoxin. leukotoxin-induced lysis and degranulation of polymorphonuclear leukocytes (pmns) and macrophages are responsible for acute inflammation and lung tissue damage characteristic of ...201627224212
a chimeric protein comprising the immunogenic domains of mannheimia haemolytica leukotoxin and outer membrane protein plpe induces antibodies against leukotoxin and plpe.mannheimia haemolytica is a very important pathogen of pneumonia in ruminants. bighorn sheep (bhs, ovis canadensis) are highly susceptible to m. haemolytica-caused pneumonia which has significantly contributed to the drastic decline of bighorn sheep population in north america. pneumonia outbreaks in wild bhs can cause mortality as high as 90%. leukotoxin is the critical virulence factor of m. haemolytica. in a 'proof of concept' study, an experimental vaccine containing leukotoxin and surface a ...201627269790
pharmacokinetics of amoxicillin trihydrate in thai swamp buffaloes (bubalus bubalis): a pilot study.this study aimed to investigate the pharmacokinetic characteristics of amoxicillin (amx) in thai swamp buffaloes, bubalus bubalis, following single intramuscular administration at two dosages of 10 and 20 mg/kg body weight (b.w.). blood samples were collected at assigned times up to 48 h. the plasma concentrations of amx were measured by liquid chromatography-tandem mass spectrometry (lc-ms/ms). the concentrations of amx in the plasma were determined up to 24 h after i.m. administration at both ...201727292774
molecular epidemiology of an outbreak of clinical mastitis in sheep caused by mannheimia haemolytica.the aetiology and epidemiology of outbreaks of clinical mastitis in sheep under extensive pastoral conditions are incompletely understood. the objective of this study was to conduct a detailed investigation of a clinical mastitis outbreak that affected more than 10% of 230 at-risk ewes on a sheep and grain producing property in south east australia during drought conditions in 2009. milk samples were collected aseptically from all affected ewes and plated on sheep blood agar for bacterial identi ...201627374911
genome sequence of bibersteinia trehalosi strain y31 isolated from the pneumonic lung of a bighorn sheep.here, we report the genome sequence for bibersteinia trehalosi strain y31, isolated from the lungs of a bighorn sheep (ovis canadensis) that had succumbed to pneumonia, which exhibits proximity-dependent inhibition (pdi) of mannheimia haemolytica the sequence will be used to understand the mechanism of pdi for these organisms.201627445392
decreasing the frequency and rate of wet brewers grains supplementation did not impact growth but reduced humoral immune response of preconditioning beef heifers.this study evaluated growth and measurements of innate and humoral immunity of preconditioning beef heifers supplemented with wet brewers grains (wbg) at 2 supplementation rates and frequencies. at 14 d after weaning (d 0), angus heifers ( = 36; 213 ± 2 kg bw and 254 ± 7 d of age) were stratified by bw and age and randomly assigned to 1 of 12 drylot pens (3 heifers/pen). treatments were randomly assigned to pens, in a 2 × 2 factorial design, and consisted of heifers provided ground tall fescue h ...201627482690
standard pk/pd concepts can be applied to determine a dosage regimen for a macrolide: the case of tulathromycin in the calf.the pharmacokinetic (pk) profile of tulathromycin, administered to calves subcutaneously at the dosage of 2.5 mg/kg, was established in serum, inflamed (exudate), and noninflamed (transudate) fluids in a tissue cage model. the pk profile of tulathromycin was also established in pneumonic calves. for mannheimia haemolytica and pasteurella multocida, tulathromycin minimum inhibitory concentrations (mic) were approximately 50 times lower in calf serum than in mueller-hinton broth. the breakpoint va ...201727501187
[bacterial resistance in bacteria isolated from the nasal cavity of swiss dairy calves].fifty-six e. coli, 37 p. multocida und 8 m. haemolytica were isolated from 157 nasal swabs taken from calves in 52 dairy herds. the antibiotic susceptibility of the organisms was determined by measurement of the minimal inhibitory concentrations. of the 56 e. coli isolates, 55.3% exhibited resistance to tetracyclines, 55.3% to sulfonamides, 39.3% to beta-lactams, 30.3% to aminoglycosides, 8.9% to fluorochinolones and 3.5% to 3rd generation cephalosporins. the 3rd generation cephalosporin- resist ...201627504835
observations on macrolide resistance and susceptibility testing performance in field isolates collected from clinical bovine respiratory disease cases.the objectives of this study were; first, to describe gamithromycin susceptibility of mannheimia haemolytica, pasteurella multocida, and histophilus somni isolated from cattle diagnosed with bovine respiratory disease (brd) and previously treated with either gamithromycin for control of brd (mass medication=mm) or sham-saline injected (control=con); second, to describe the macrolide resistance genes present in genetically typed m. haemolytica isolates; third, use whole-genome sequencing (wgs) to ...201627527782
two outer membrane proteins are bovine lactoferrin-binding proteins in mannheimia haemolytica a1.mannheimia haemolytica is a gram negative bacterium that is part of the bovine respiratory disease, which causes important economic losses in the livestock industry. in the present work, the interaction between m. haemolytica a1 and bovine lactoferrin (blf) was studied. this iron-chelating glycoprotein is part of the mammalian innate-immune system and is present in milk and mucosal secretions; lf is also contained in neutrophils secondary granules, which release this glycoprotein at infection si ...201627599994
alopecia in lambs associated with micronutrient-deficient milk replacer.▪ alopecia associated with micronutrient deficiency in lambs fed milk replacer▪ idiopathic necrotising enteritis in suckler calves▪ mannheimia haemolytica abomasitis in a five-week-old calf▪ increased diagnoses of nematodirosis in lambs▪ enteric and spinal listeriosis in sheepthese are among matters discussed in the disease surveillance report for june 2016 from sac consulting: veterinary services (sac c vs).201627660354
identification of leukotoxin and other vaccine candidate proteins in a mannheimia haemolytica commercial antigen.bovine respiratory disease is the most costly disease that affects beef and dairy cattle industry. its etiology is multifactorial, arising from predisposing environmental stress conditions as well as the action of several different respiratory pathogens. this situation has hindered the development of effective control strategies. although different type of vaccines are available, many currently marketed vaccines are based on inactivated cultures of the main viral and bacterial agents involved in ...201627699279
pharmacokinetics (pk), pharmacodynamics (pd), and pk-pd integration of ceftiofur after a single intravenous, subcutaneous and subcutaneous-la administration in lactating goats.bacterial pneumonia in goats is usually caused by mannheimia haemolytica and pasteurella multocida. another important infection disease in lactating goats is intramammary infection producing mastitis, usually associated with coagulase-negative staphylococcus spp. however, treatment of bacterial pneumonia in goats not affected by mastitis problems should be restricted to antimicrobials with scant penetration to milk in order to avoid long withdrawal times. ceftiofur is a third-generation cephalos ...201627737655
mannheimia haemolytica and bibersteinia trehalosi serotypes isolated from merino breed lambs in extremadura (southwestern spain).pneumonia caused by mannheimia haemolytica is an important disease in ruminants. because of its economic significance, several methods have been developed to study the pathogenicity and epidemiology of m. haemolytica. in this study, bacterial isolates of m. haemolytica and bibersteinia trehalosi identified from the lungs of sheep were serotyped by means of indirect haemagglutination. of the 598 lungs studied, 34 isolates were identified and serotyped. in decreasing order, m. haemolytica serotype ...201627784951
precise gene editing paves the way for derivation of mannheimia haemolytica leukotoxin-resistant cattle.signal peptides of membrane proteins are cleaved by signal peptidase once the nascent proteins reach the endoplasmic reticulum. previously, we reported that, contrary to the paradigm, the signal peptide of ruminant cd18, the β subunit of β2 integrins, is not cleaved and hence remains intact on mature cd18 molecules expressed on the surface of ruminant leukocytes. leukotoxin secreted by mannheimia (pasteurella) haemolytica binds to the intact signal peptide and causes cytolysis of ruminant leukoc ...201627799556
a large potentiation effect of serum on the in vitro potency of tulathromycin against mannheimia haemolytica and pasteurella multocida.the antimicrobial properties of tulathromycin were investigated for m. haemolytica and p. multocida. three in vitro indices of antimicrobial activity, minimum inhibitory concentration (mic), minimum bactericidal concentration (mbc) and time-kill curves, were established for six isolates of each organism. each index was measured in two growth media: mueller-hinton broth (mhb) and calf serum. it was shown that mics and mbcs were markedly lower in serum than in mhb. mhb:serum ratios for mic were 47 ...201627891615
nitric oxide modulates the immunological response of bovine pbmcs in an in vitro brdc infection model.bovine respiratory disease complex (brdc) is a multi-factorial disease, involving both viral and bacterial pathogens, that negatively impacts the cattle feedlot industry. a nitric oxide releasing solution (nors) has been developed and shown to have potential in the prevention of brdc. this study investigated the underlying immunological mechanisms through which the nitroslyating agent nors provides protection against the development of brdc in susceptible cattle. an in vitro brdc experimental mo ...201627892870
genomic signatures of mannheimia haemolytica that associate with the lungs of cattle with respiratory disease, an integrative conjugative element, and antibiotic resistance genes.mannheimia haemolytica typically resides in cattle as a commensal member of the upper respiratory tract microbiome. however, some strains can invade their lungs and cause respiratory disease and death, including those with multi-drug resistance. a nucleotide polymorphism typing system was developed for m. haemolytica from the genome sequences of 1133 north american isolates, and used to identify genetic differences between isolates from the lungs and upper respiratory tract of cattle with and wi ...201627894259
mannheimia haemolytica biofilm formation on bovine respiratory epithelial cells.mannheimia haemolytica is the most important bacterial agent associated with the bovine respiratory disease complex (brdc), which causes worldwide economic losses to the cattle industry. m. haemolytica cells initially colonize the tonsillar crypts in the upper respiratory tract of cattle, from where they can subsequently descend into the lungs to cause disease. many bacteria exist as biofilms inside their hosts. we hypothesize that m. haemolytica colonization of cattle during its commensal state ...201627938674
comparison of standardised versus non-standardised methods for testing the in vitro potency of oxytetracycline against mannheimia haemolytica and pasteurella multocida.the in vitro pharmacodynamics of oxytetracycline was established for six isolates of each of the calf pneumonia pathogens mannheimia haemolytica and pasteurella multocida. minimum inhibitory concentration (mic), minimum bactericidal concentration (mbc) and bacterial time-kill curves were determined in two matrices, mueller hinton broth (mhb) and calf serum. geometric mean mic ratios, serum:mhb, were 25.2:1 (m. haemolytica) and 27.4:1 (p. multocida). the degree of binding of oxytetracycline to se ...201627938710
deciphering upper respiratory tract microbiota complexity in healthy calves and calves that develop respiratory disease using shotgun metagenomics.bovine respiratory disease (brd) is a multifactorial disorder responsible for severe economic losses in dairy and feedlot herds. advances in next-generation sequencing mean that microbial communities in clinical samples, including non-culturable bacteria, can be characterized. our aim was to evaluate the microbiota of the upper respiratory tract of healthy calves and calves with brd using whole-genome sequencing (shotgun metagenomics). we performed deep nasopharyngeal swabs on 16 holstein heifer ...201727988122
short communication: interaction of the isomers carvacrol and thymol with the antibiotics doxycycline and tilmicosin: in vitro effects against pathogenic bacteria commonly found in the respiratory tract of calves.bovine respiratory disease is the major problem faced by cattle, specially calves, leading to reduced animal performance and increased mortality, consequently causing important economic losses. hence, calves must be submitted to antibiotic therapy to counteract this infection usually initiated by the combination of environmental stress factors and viral infection, altering the animal's defense mechanism, and thus allowing lung colonization by the opportunistic bacteria mannheimia haemolytica and ...201728012625
new interpretive criteria for danofloxacin antibacterial susceptibility testing against mannheimia haemolytica and pasteurella multocida associated with bovine respiratory disease.danofloxacin is a fluoroquinolone antibacterial agent approved for use in veterinary medicine to treat and control bovine respiratory disease caused by mannheimia haemolytica or pasteurella multocida. susceptible minimal inhibitory concentration (mic) breakpoint (≤0.25 µg/ml) and disk diffusion interpretive criteria (≥22 mm) values for danofloxacin against m. haemolytica and p. multocida were first approved by the clinical and laboratory standards institute (clsi) in 2003. however, intermediate ...201728064562
development of a one-run real-time pcr detection system for pathogens associated with bovine respiratory disease complex.bovine respiratory disease complex (brdc) is frequently found in cattle worldwide. the etiology of brdc is complicated by infections with multiple pathogens, making identification of the causal pathogen difficult. here, we developed a detection system by applying taqman real-time pcr (dembo respiratory-pcr) to screen a broad range of microbes associated with brdc in a single run. we selected 16 bovine respiratory pathogens (bovine viral diarrhea virus, bovine coronavirus, bovine parainfluenza vi ...201728070089
pathogens, patterns of pneumonia, and epidemiologic risk factors associated with respiratory disease in recently weaned cattle in ireland.we examined the pathogens, morphologic patterns, and risk factors associated with bovine respiratory disease (brd) in 136 recently weaned cattle ("weanlings"), 6-12 mo of age, that were submitted for postmortem examination to regional veterinary laboratories in ireland. a standardized sampling protocol included routine microbiologic investigations as well as polymerase chain reaction and immunohistochemistry. lungs with histologic lesions were categorized into 1 of 5 morphologic patterns of pneu ...201728074713
probiotic bacteria inhibit the bovine respiratory pathogen mannheimia haemolytica serotype 1 in vitro.this study evaluated the potential of probiotic bacteria to inhibit growth and cell adhesion of the bovine respiratory pathogen mannheimia haemoltyica serotype 1. the inhibitory effects of nine probiotic strains (lactobacillus acidophilus, lactobacillus casei, lactobacillus helveticus, lactobacillus plantarum, lactobacillus rhamnosus, lactococcus lactis, streptococcus thermophilus and two paenibacillus polymyxa strains) against m. haemolytica were evaluated using a spot-on-lawn method. probiotic ...201728178767
immunization of bighorn sheep against mannheimia haemolytica with a bovine herpesvirus 1-vectored vaccine.mannheimia haemolytica is an important pathogen of pneumonia in bighorn sheep (bhs), consistently causing 100% mortality under experimental conditions. leukotoxin is the critical virulence factor of m. haemolytica. in a 'proof of concept' study, a vaccine containing leukotoxin and surface antigens of m. haemolytica induced 100% protection in bhs, but required multiple booster doses. vaccination of wildlife is difficult. bhs, however, can be vaccinated at the time of transplantation, but administ ...201728228321
comparison of the diagnostic performance of bacterial culture of nasopharyngeal swab and bronchoalveolar lavage fluid samples obtained from calves with bovine respiratory disease.objective to compare predictive values, extent of agreement, and gamithromycin susceptibility between bacterial culture results of nasopharyngeal swab (nps) and bronchoalveolar lavage fluid (balf) samples obtained from calves with bovine respiratory disease (brd). animals 28 beef calves with clinical brd. procedures pooled bilateral nps samples and balf samples were obtained for bacterial culture from calves immediately before and at various times during the 5 days after gamithromycin (6 mg/kg, ...201728240958
rapid typing of mannheimia haemolytica major genotypes 1 and 2 using maldi-tof mass spectrometry.genotype 2m. haemolytica predominantly associate over genotype 1 with the lungs of cattle with respiratory disease and ices containing antimicrobial resistance genes. distinct protein masses were detected by maldi-tof ms between genotype 1 and 2 strains. maldi-tof ms could rapidly differentiate genotype 2 strains in veterinary diagnostic laboratories.201728267571
the bovine paranasal sinuses: bacterial flora, epithelial expression of nitric oxide and potential role in the in-herd persistence of respiratory disease pathogens.the bovine paranasal sinuses are a group of complex cavernous air-filled spaces, lined by respiratory epithelium, the exact function of which is unclear. while lesions affecting these sinuses are occasionally reported in cattle, their microbial flora has not been defined. furthermore, given that the various bacterial and viral pathogens causing bovine respiratory disease (brd) persist within herds, we speculated that the paranasal sinuses may serve as a refuge for such infectious agents. the par ...201728282443
differential susceptibility of bighorn sheep (ovis canadensis) and domestic sheep (ovis aries) neutrophils to mannheimia haemolytica leukotoxin is not due to differential expression of cell surface cd18.bighorn sheep ( ovis canadensis ) are more susceptible to pneumonia caused by mannheimia haemolytica than are domestic sheep ( ovis aries ). leukotoxin produced by m. haemolytica is the principal virulence factor involved in pneumonia pathogenesis. although leukotoxin is cytolytic to all subsets of ruminant leukocytes, neutrophils are the most susceptible subset. bighorn sheep neutrophils are 4- to 8-fold more susceptible to leukotoxin-induced cytolysis than are domestic sheep neutrophils. we hy ...201728323564
the nasopharyngeal microbiota of beef cattle before and after transport to a feedlot.the nasopharyngeal (np) microbiota plays an important role in bovine health, comprising a rich and diverse microbial community. the nasopharynx is also the niche for potentially pathogenic agents which are associated with bovine respiratory disease (brd), a serious and costly illness in feedlot cattle. we used 14 beef heifers from a closed and disease-free herd to assess the dynamics of the np microbiota of cattle that are transported to a feedlot. cattle were sampled prior to transport to the f ...201728330466
genome sequence of a spontaneous nonhemolytic mutant of mannheimia haemolytica 16041065 gh.we report here the draft genome sequence of a spontaneous nonhemolytic mutant of mannheimia haemolytica 16041065 gh. this mutant arose during routine passage and was devoid of hemolytic activity on standard blood agars. this genome sequence had a total size of 2.7 mb with an n50 of 117 kb.201728385858
genome sequence of mannheimia haemolytica serotype 1 strain 16041065 bh.here, we report the genome sequence of mannheimia haemolytica serotype 1 strain 16041065 bh, which was recently isolated from a midwestern calf that died due to mannheimia haemolytica-induced pneumonia. this genome comprised a total of 2.7 mb, with an n50 of 122 kb, and maintained hemolytic activity when grown on blood heart infusion agar supplemented with 5% sheep's blood.201728385859
effects of organic complexed or inorganic co, cu, mn and zn supplementation during a 45-day preconditioning period on productive and health responses of feeder cattle.this experiment evaluated production and health parameters among cattle offered concentrates containing inorganic or organic complexed sources of supplemental cu, co, mn and zn during a 45-day preconditioning period. in total, 90 angus×hereford calves were weaned at 7 months (day -1), sorted by sex, weaning bw and age (261±2 kg; 224±2 days), and allocated to 18 drylot pens (one heifer and four steers per pen) on day 0; thus, all pens had equivalent initial bw and age. pens were randomly assigned ...201728514971
pharmacokinetic/pharmacodynamic evaluation of marbofloxacin as a single injection for pasteurellaceae respiratory infections in cattle using population pharmacokinetics and monte carlo simulations.population pharmacokinetic of marbofloxacin was investigated with 52 plasma concentration-time profiles obtained after intramuscular administration of forcyl® in cattle. animal's status, pre-ruminant, ruminant, or dairy cow, was retained as a relevant covariate for clearance. monte carlo simulations were performed using a stratification by status, and 1000 virtual disposition curves were generated in each bovine subpopulation for the recommended dosage regimen of 10 mg/kg as a single injection. ...201728542866
a multiplex pcr assay for molecular capsular serotyping of mannheimia haemolytica serotypes 1, 2, and 6.mannheimia haemolytica is an important respiratory pathogen of ruminants. of the 12 capsular serovars identified, 1 and 6 are most frequently associated with disease in cattle, while 2 is largely a commensal. comparative analysis of 24 m. haemolytica genomes was used to identify unique genes associated with capsular polysaccharide synthesis as amplification targets in a multiplex pcr assay to discriminate between serotype 1, 2, and 6 strains. the specificity of serotype specific gene targets was ...201728551457
efficacy and safety of ban huang oral liquid for treating bovine respiratory diseases.ban huang oral liquid was developed as a veterinary compound preparation by the lanzhou institute of husbandry and pharmaceutical sciences of the chinese academy of agricultural sciences (caas). the purpose of this study was to determine whether the oral liquid preparation of traditional chinese medicine, ban huang, is safe and effective for treating respiratory diseases in cattle.201728573221
effect of vaccination against pneumonia on the survival of bighorn sheep (ovis canadensis) commingled with carrier animals.leukotoxin producing (lkt+) members of pasteurellaceae, particularly mannheimia haemolytica and bibersteinia trehalosi are important pathogens of pneumonia in bighorn sheep (bhs; ovis canadensis), causing fatal disease. predisposing or concurrent infection with mycoplasma ovipneumoniae enhances the severity of the disease, resulting in increased morbidity and mortality. several studies have investigated the effectiveness of vaccines against lkt+ members of pasteurellaceae in preventing fatal pne ...201728619167
proteomic and bioinformatic analyses of putative mannheimia haemolytica secretome by liquid chromatography and tandem mass spectrometry.mannheimia haemolytica is a major bacterial contributor to bovine respiratory disease complex that costs the livestock industry a billion dollars a year in usa. commercial vaccines are only partially efficacious under field conditions. earlier studies found that outer membrane protein preparations and culture supernatants can induce immune responses that enhance resistance to challenge by m. haemolytica strains. the objective of this study was to characterize secretome of two m. haemolytica stai ...201728619171
evaluation of a multiplex real-time pcr for detection of four bacterial agents commonly associated with bovine respiratory disease in bronchoalveolar lavage fluid.pasteurella multocida, mannheimia haemolytica, histophilus somni and trueperella pyogenes are four bacterial agents commonly associated with bovine respiratory disease (brd). in this study a bacterial multiplex real-time pcr (the respocheck pcr) was evaluated for the detection in bronchoalveolar lavage fluid (balf) of these four bacterial agents.201728705198
assessing respiratory pathogen communities in bighorn sheep populations: sampling realities, challenges, and improvements.respiratory disease has been a persistent problem for the recovery of bighorn sheep (ovis canadensis), but has uncertain etiology. the disease has been attributed to several bacterial pathogens including mycoplasma ovipneumoniae and pasteurellaceae pathogens belonging to the mannheimia, bibersteinia, and pasteurella genera. we estimated detection probability for these pathogens using protocols with diagnostic tests offered by a fee-for-service laboratory and not offered by a fee-for-service labo ...201728708832
x-ray crystallographic structure of a bacterial polysialyltransferase provides insight into the biosynthesis of capsular polysialic acid.polysialic acid (polysia) is a homopolymeric saccharide that is associated with some neuroinvasive pathogens and is found on selective cell types in their eukaryotic host. the presence of a polysia capsule on these bacterial pathogens helps with resistance to phagocytosis, cationic microbial peptides and bactericidal antibody production. the biosynthesis of bacterial polysia is catalysed by a single polysialyltransferase (pst) transferring sialic acid from a nucleotide-activated donor to a lipid ...201728724897
pharmacokinetic-pharmacodynamic integration and modelling of oxytetracycline for the calf pathogens mannheimia haemolytica and pasteurella multocida.a calf tissue cage model was used to study the pharmacokinetics (pk) and pharmacodynamics (pd) of oxytetracycline in serum, inflamed (exudate) and noninflamed (transudate) tissue cage fluids. after intramuscular administration, the pk was characterized by a long mean residence time of 28.3 hr. based on minimum inhibitory concentrations (mics) for six isolates each of mannheimia haemolytica and pasteurella multocida, measured in serum, integration of in vivo pk and in vitro pd data established ar ...201728736817
whole-genome sequencing and concordance between antimicrobial susceptibility genotypes and phenotypes of bacterial isolates associated with bovine respiratory disease.extended laboratory culture and antimicrobial susceptibility testing timelines hinder rapid species identification and susceptibility profiling of bacterial pathogens associated with bovine respiratory disease, the most prevalent cause of cattle mortality in the united states. whole genome sequencing offers a culture-independent alternative to current bacterial identification methods but requires a library of bacterial reference genomes for comparison. to contribute new bacterial genome assembli ...201728739600
behavioral and physiologic changes in holstein steers experimentally infected with mannheimia haemolytica.objective to evaluate changes in behavior and surfactant protein (sp) a and d concentrations in serum and bronchoalveolar lavage fluid (balf) samples of calves experimentally infected with mannheimia haemolytica. animals twelve 4- to 5-month-old holstein steers. procedures calves were divided into 2 treatment groups and instrumented with a data logger to collect behavioral data. after 10 days of acclimation, calves were experimentally inoculated with 3 × 10(9) cfus to 5 × 10(9) cfus of m haemoly ...201728836844
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