The rapid emergence and spread of colistin-resistant gram-negative bacteria has raised worldwide public health concerns,and phosphoethanolamine(PEtn)transferase modification-mediated colistin resistance has been widel...The rapid emergence and spread of colistin-resistant gram-negative bacteria has raised worldwide public health concerns,and phosphoethanolamine(PEtn)transferase modification-mediated colistin resistance has been widely documented in multiple gram-negative bacterial species.However,whether such a mechanism exists in the zoonotic pathogen Pasteurella multocida is still unknown.Recently,a novel PEtn transferase,PetL,was identified in P.multo-cida,but whether it is associated with colistin resistance remains to be elucidated.In this study,we found that PetL in P.multocida(PetL^(PM))exhibited structural characteristics similar to those of the mobile-colistin-resistant(MCR)protein and the PEtn transferase characterized in Neisseria meningitidis.The transformation of petLPM into E.coli or K.pneumoniae changed the phenotype of several tested strains from colistin sensitive to colistin resistant.Deletion of this gene decreased the colistin minimum inhibitory concentration(MIC)of P.multocida by 64-fold.Our extensive analysis by MALDI-TOF-MS demonstrated that PetLPM participated in the modification of bacterial lipopolysaccharide(LPS)-lipid A.Deletion of petL^(PM) led to an increase in membrane charge but a decrease in cell-surface hydrophobicity and cell permeability in P.multocida.The present study is the first to report the presence of PEtn transferase-mediated colistin resistance in the zoonotic pathogen P.multocida.展开更多
Pasteurella multocida, a Gram-negative nonmotile coccobacillus, is the causative agent of fowl cholera, bovine hemorrhagic septicemia, enzoonotic pneumonia and swine atropic rhinitis. Two filamentous hemagglutinin gen...Pasteurella multocida, a Gram-negative nonmotile coccobacillus, is the causative agent of fowl cholera, bovine hemorrhagic septicemia, enzoonotic pneumonia and swine atropic rhinitis. Two filamentous hemagglutinin genes, fhaB1 and JhaB2, are the potential virulence factors. In this study, an inactivationfhaB1 mutant ofP. multocida in avian strain C48-102 was constructed by a kanamycin-resistance cassette. The virulence of thefhaB1 mutant and the wild type strain was assessed in chickens by intranasal and intramuscular challenge. The inactivation offhaB1 resulted in a high degree of attenuation when the chickens were challenged intranasally and a lesser degree when challenged intramuscularly. ThefhaB1 mutant and the wild type strain were investigated their sensitivity to the antibody-dependent classical complement-mediated killing pathway in 90% convalescent chicken serum. ThefhaB1 mutant was serum sensitive as the viability has reduced between untreated serum and heat inactivated chicken serum （P〈0.007）. These results confirmed that FhaB1 played the critical roles in the bacterial pathogenesis and further studies were needed to investigate the mechanism which caused reduced virulence of the fhaB1 mutant.展开更多
[Objective]To develop multiplex-PCR for diagnosis of mixed infection caused by Pasteurella multocida(PM),Haomophilus parasuis(HPS)and Actinbaci/lus pleuropneumoniae(App).[Method]PCR method was developed to detect sing...[Objective]To develop multiplex-PCR for diagnosis of mixed infection caused by Pasteurella multocida(PM),Haomophilus parasuis(HPS)and Actinbaci/lus pleuropneumoniae(App).[Method]PCR method was developed to detect single infection caused by PM,HPS or App.The conditions of amplification and primers were optimized,and the multiple-PCR was developed to detect mixed infection of PM,HPS and App.[Result]A 457-bp band,a 821-bp band and a 342-bp band were simultaneously amplified in the one PCR reaction system.The method had high sensitivity and specificity.[Conduslon]The multiple-PCR is successfully developed and can be used for differential diagnosis of PM,HPS and App.展开更多
Animal bites are frequently encountered in the emergency department(ED). Aortitis leading to mycotic abdominal aortic aneurysm is a rare and potentially deadly complication of Pasteurella multocida(P. multocida) follo...Animal bites are frequently encountered in the emergency department(ED). Aortitis leading to mycotic abdominal aortic aneurysm is a rare and potentially deadly complication of Pasteurella multocida(P. multocida) following an animal bite. We present the case of a 68-year-old male who presented to the ED after falling at home. He complained of weakness and abdominal pain. He was in septic shock and was treated empirically with broad-spectrum antibiotics and intravenous fluids. He reported previous antibiotic treatment of a cellulitis secondary to a cat bite injury to his right thumb four weeks prior. Abdominal ultrasound and subsequent computed tomography scan revealed a leaking mycotic abdominal aneurysm that was surgically repaired. Blood cultures and aortic wall tissue cultures grew P. multocida. Given how common animal bite presentations are in the ED, this case highlights the need to consider aortitis and mycotic abdominal aortic aneurysm in an unwell patient with an animal bite.展开更多
Respiratory diseases are one of the most important health problems in pig herds. The porcine respiratory disease complex (PRDC) is the term used to describe pneumonic diseases caused by multiple infectious agents that...Respiratory diseases are one of the most important health problems in pig herds. The porcine respiratory disease complex (PRDC) is the term used to describe pneumonic diseases caused by multiple infectious agents that provoke weight loss in animals or death. In the PRDC multiple pathogens (bacteria and/or viruses) work in combination to induce this respiratory disease. Within this complex, Actinobacillus pleuropneumoniae, Streptococcus suis, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis and Mycoplasma hyopneumoniae are the main bacterial pathogens involved in great economic losses to the swine industry. The aim of this work was to estimate the presence of A. pleuropneumoniae, S. suis, P. multocida, B. bronchiseptica, H. parasuis and M. hyopneumoniae in the upper respiratory tract of pigs in representative swine farms inAguascalientes,Mexico, using PCR technique. The study was performed in 14 swine farms. We obtained a total of 212 nasal swabs. Near 20% of samples were positive for A. pleuropneumoniae (located in the 79% of farms);17% were positive for S. suis (in 86% of farms), of these, 3% were S. suis serovar 2;30% were positive for H. parasuis (93% of farms);23% of the samples to P. multocida (in 79% of farms);and 19% to M. hyopneumoniae (in 64% of farms). B. bronchiseptica was not detected in this study. The results obtained show that bacterial pathogens of PRDC were present in the upper respiratory tract of pigs in all farms studied;therefore, these pathogens are widely disseminated in pig farms of Aguascalientes, Mexico.展开更多
Pasteurella species is considered the principal pathogen of the respiratory tract.Mannheimia haemolytica and Pasteurella multocida were investigated and typed from nasal swabs and tissues taken from sheep,goat and cat...Pasteurella species is considered the principal pathogen of the respiratory tract.Mannheimia haemolytica and Pasteurella multocida were investigated and typed from nasal swabs and tissues taken from sheep,goat and cattle.Indeed,41 lung and 121 nasal swabs samples were collected from animals with respiratory diseases during 2015 to 2017 in six different regions in Morocco.At first,a screening of Pasteurella species using the real time PCR(RT-PCR)was carried out,then all isolated strains on agar blood were confirmed by PCR gel based assay specific for M.haemolytica and P.multocida.Pathogenicity was evaluated in mice and histopathological examination was done on some of lung tissue.The results revealed that 34 samples of which 28(55%)from nasal swabs and six(38%)from lungs were positive for M.haemolytica and nine samples of which seven(14%)from nasal swabs and two(13%)from lungs were positive on P.multocida serogroup A.Seventy-two percent(72%)isolates were highly pathogenic to mice,which is in accordance with the results obtained by histopathology examination.This is the first report for widespread infections of Pasteurella(M.haemolytica&P.multocida)in ruminants in Morocco.Therefore,measures including development of vaccines are highly required to mitigate the impact of the bacteria in animals.展开更多
Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve ...Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve this,we briefly investigated 158 P.multocida isolates from pigs with respiratory disorders in China between 2019 and 2020.Genotyping through multiplex PCR assays assigned these 158 isolates into capsular genotypes A(60.13%,95/158),D(35.44%,56/158),F(4.43%,7/158),and/or lipopolysaccharide(LPS)genotypes L3(28.48%,45/158)and L6(66.46%,105/158).In addition,eight isolates(5.06%,8/158)were found to be nontypable using the LPS genotyping method.When combining the capsular genotypes and the LPS genotypes,D:L6(34.81%,55/158)and A:L6(31.65%,50/158)were the predominant genotypes,followed by A:L3(24.05%,38/158).PCR detection of virulence factor-encoding genes showed that over 80%of the isolates were positive for exbB,tonB,exbD,ompH,ptfA,fimA,sodA,sodC,fur,ompA,oma87,plpB,hsf-2,nanH and hgbB,suggesting the presence of these genes were broad characteristics of P.multocida.We also found approximately 63.92%(101/158),51.27%(81/158),8.86%(14/158),7.59%(12/158),3.16%(5/158),0.63%(1/158),and 0.63%(1/158)of the isolates grew well in media with the presence of colistin(4μg/mL),tetracycline(16μg/mL),tigecycline(1μg/mL),ampicillin(32μg/mL),chloramphenicol(32μg/mL),cefepime(16μg/mL),and ciprofloxacin(1μg/mL),respectively.This study contributes to the understanding of genotypes and antimicrobial resistance profile of P.multocida currently circulation in pigs of China.展开更多
Objective:To characterize Pasteurella isolated from backyard chickens using whole cell protein lysate profiles and random amplified polymorphic DNA(RAPD)techniques to show their genetic relationship because Pasteurcll...Objective:To characterize Pasteurella isolated from backyard chickens using whole cell protein lysate profiles and random amplified polymorphic DNA(RAPD)techniques to show their genetic relationship because Pasteurclla multocida(P.multocida)is an important cause of fatal infections in backyard chickens.Methods:Twenty one P.multocida isolates were recovered previously from clinical cases of fowl cholera belonging to individual owners and phenotypically analysed using biochemical tests and serotyping were used far the genetic characterization.Results:Phylogenetic study based on both methods revealed that the recovered population of P.multocida isolated from backyard chickens differs markedly,constituting a well-separated cluster and appearance of 3 distinguishing lineages with greater discrimination shown by RAPDPCR that resulted in two suclusters in cluster A and three subclusters in cluster B and were related greatly with capsular serogroups for the examined strains.The whole cell protein revealed the presence of dominant protein bands at approximately 41 and 61 kDa in all of the examined isolates that may be a virulent proteins share in the increasing of its pathogenicity.Clear distinctive bands ranged from 123 to 1534 bp.Conclusions:Based on the previous findings,there are three spreading clusters that may indicate the association of a small number of P.multocida variants with the majority of cases suggesting that certain clones of P.multocida are able to colonue the examined backyard chickens.Also,the ease and rapidity of RAPD-PCR support the use of this technique as alternative to the more labour-intensive SDS-PACE system for strain differentiation and epidemiological studies of avian P.multocida.Further application of RAPD technology to the examination of avian cholera outbreaks in commercially available flocks may facilitate more effective management of this disease by providing the potential to investigate correlations of P.multocida genotypes,to identify affiliations between bird types and bacterial genotypes,and to elucidate the role of specific bird species in disease transmission.展开更多
The control and prevention of pasteurellosis in rabbits which makes the hosts unsuitable for experimental use raised the needs to improve and simplify the procedures of Enzyme-Linked Immunosorbent Assay (ELISA) for de...The control and prevention of pasteurellosis in rabbits which makes the hosts unsuitable for experimental use raised the needs to improve and simplify the procedures of Enzyme-Linked Immunosorbent Assay (ELISA) for detect of antibody against P.multocida. A comparison on the sensitivity and specificity of bacterial culture of antemortem and postmortem samples, complement fixation test and enzyme-linked immunosorbent assay of 11 apparently healthy adult rabbits was conducted. The incidence rates showed 45.45%,54.54% and 72.73% respectively. The sensitivity for the three methods were 0.63, 0.67,and 1.00,and specificity for them were 1.00, 0.67 and 1.00 respectively. Somatic serotypes of isolates of P.multocida from rabbits of three groups (rabbits of group 2 were with clinic signs, those of groups 1 and 3 were apparently healthy) revealed no remarkable differences,and the predominant types were type 3 and type 3, 4. This was somewhat different from the reports derived from other states. As the antigen of different serotype used in ELISA may have different sensitivity and specificity, which is affected also by different preparation method, a type non-specific antigen should be selected to meet such request. The trial of accomplishment of ELISA without positive and negative controls was presented for discussion.展开更多
Objective:To evaluate the effects of Pasteurella multocida(P.multocida)vaccines on the expression and release of antibodies,interleukin(IL)-6 and IL-12 by serum.Methods:Balb/c mice were immunized with two formalin and...Objective:To evaluate the effects of Pasteurella multocida(P.multocida)vaccines on the expression and release of antibodies,interleukin(IL)-6 and IL-12 by serum.Methods:Balb/c mice were immunized with two formalin and iron inactivated vaccine doses within 2 weeks.The vaccines were adjuvant with P.multocida A strain,P.multocida B strain and Salmonella typhimurium bacterial DNA(AbDNA,BbDNA and SbDNA for short,respectively).The animals were challenged 4 weeks after immunization.Blood of mice was collected to detect the change of specific antibody,IL-6,and IL-12 using ELISA.Results:The specific antibody and interleukins in the immunized group increased significantly compared to the control mice after vaccination and challenge(P<0.05).The highest release of these cytokines was obtained by P.multocida inactivated with iron and adjuvant with AbDNA at a concentration of 25μg/mL.The antibody titer peak was 0.447 in mice vaccinated with iron-killed whole-cell antigen adjunct with AbDNA.The time-courses of release showed that bacterial DNA was able to stimulate IL-6 and IL-12 production more than alum(P<0.05).Conclusions:Our findings introduce that bacterial DNA is capable of releasing an immunological response with several cytokines.These indicate that bacterial DNA entrapped with killed P.multocida antigen is a new and effective adjuvant to enhance specific immunity and resistance of animal against the infectious pathogen,which could simplify the development of highly promising strong adjuvant.展开更多
[Objective] To study on genetic inactivation bacterial ghosts of Pasteurella multocida based PhiX174 gene E lysis cassette mediated. [ Method ] Recombinant pPBA1100-e was constructed by which the gene E of bacteriopha...[Objective] To study on genetic inactivation bacterial ghosts of Pasteurella multocida based PhiX174 gene E lysis cassette mediated. [ Method ] Recombinant pPBA1100-e was constructed by which the gene E of bacteriophage Phix174 and temperature sensitivity expressing control system hybridized with plasmid pPBA1100 by genetic engineering method. Recombinant was transformed to Pasteurella multocida and lysis gene E expressed by temperature induction. Recombinant was detected by restriction endonuclease. Cell morphology of bacterial ghost of Pasteurella mul- tocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysis. I Result~ The results indicated that the recombination plasmid presented three bands by restriction endonuclease and agarose electrophoresis and that molecular weight of every band ac- corded with theoretical value. The result of SEM observing showed that recombination plasmid expressed successfully in P. multocida and produced bacterial ghost. The result of CFU detecting demonstrated that inactivation ratio of P. multocida reached 99 per cent. ~Conclusion~ This study pro- vided technical bases for the preparation of antigen vaccine of natural bacterial outer membrane protein.展开更多
Pasteurellosis is the most prevalent, extremely contagious bacterial disease among domestic rabbits and is considered the leading cause of deaths in rabbits, resulting in enormous economic losses to the rabbit industr...Pasteurellosis is the most prevalent, extremely contagious bacterial disease among domestic rabbits and is considered the leading cause of deaths in rabbits, resulting in enormous economic losses to the rabbit industry. Screening for bacterial agents causing mortalities in rabbits revealed the presence of Enterobacteriacae species in approximately 42% of studied cases, with E. coli the most commonly isolated organism. The present study was designed to evaluate the immune response of rabbits vaccinated with a locally prepared, combined inactivated vaccine of Pasteurella multocida and E. coli, adjuvanated with Montanide ISA70. A total of 370 rabbits, aged 2 - 3 weeks, were divided into four groups: (G1) vaccinated with a polyvalent P. multocida vaccine, (G2) vaccinated with a polyvalent E. coli vaccine, (G3) vaccinated with a combined inactivated Montanide ISA70 vaccine of P. multocida and E. coli, and (G4) kept as a non-vaccinated control group. All rabbits received two doses of 0.5 ml of the prepared vaccines, administered one month apart, and were then challenged with virulent strains of P. multocida and E. coli three weeks after the second vaccination. The prepared vaccines were evaluated by determining humoral immunity using indirect haemagglutination (IHA) test and ELISA. The potency of the vaccines was assessed through challenge and determination of LD50. Experimental findings on the prepared polyvalent combined inactivated P. multocida and E. coli vaccine indicated that it is a potent vaccine, producing the highest antibody titers and a 90% protection rate against challenges with virulent strains of P. multocida type A, D2, and E. coli types O157, O151 and O125. Thus, this vaccine is promising in addressing both P. multocida and E. coli problems in rabbits, farms, providing significant protection, and we recommend its commercial production to help rabbit producers control these two major bacterial infections.展开更多
In this study,55 suspected pasteurellosis clinical cases from different provinces of Morocco were investigated.Molecular analysis revealed that 47%of samples were positive for Pasteurella multocida,all typed as serogr...In this study,55 suspected pasteurellosis clinical cases from different provinces of Morocco were investigated.Molecular analysis revealed that 47%of samples were positive for Pasteurella multocida,all typed as serogroup A,and 11%positive for Mannheimia heamolytica.Eight isolates were recovered from 26 P.multocida positive samples,and characterized by biochemical and molecular typing methods.Among these isolates,two strains(S13 and S14)were selected for genes(RNA16S and rpoB)sequence analysis and virulence study in mice,guinea pigs and sheep.Phylogeny study showed similarities of both S14 and S13 isolates with strains from other species.In laboratory animals,the strain S14 was more virulent than S13 and induced severe illness in sheep.The high mortality of infected mice suggests that this model may represent an alternative for testing pathogenicity and vaccine efficacy.展开更多
<strong>Background:</strong> This work evaluated the capacity of a dry emulsion as a carrier of viable microorganisms with potential use as prophylaxis of infectious diseases. <strong>Methods:</st...<strong>Background:</strong> This work evaluated the capacity of a dry emulsion as a carrier of viable microorganisms with potential use as prophylaxis of infectious diseases. <strong>Methods:</strong> The aqueous phase containing <em>P. multocida </em>not viable in PBS was emulsified in mineral oil to obtain a w/o emulsion. The microorganisms remained stable and only in two cases (n = 6) did the bacterial concentration decrease. Scanning Electron Microscopy (SEM) revealed a structure of a system with the organized association of particles with cubic symmetry. Using two <em>ex vivo </em>bioadhesion systems, it was demonstrated that the disperse-adsorbed system is capable of adhering to the intestinal mucosa and remains adhered for long periods of time. <strong>Results: </strong>The no viability of the bacteria in the dry emulsion and the possibility of controlled release were confirmed. <em>In vivo </em>trial was conducted in pigs. It was possible to locate the emulsion and the bacteria attached to the gut of the living animal. An ELISA kit was used to monitor the mean antibody titer of treated pigs over a 2-week period, and a classic primary response curve occurred when the titer was plotted against time. <strong>Conclusion: </strong>We propose the disperse-adsorbed system as an alternative to commonly used vehicles for immunogens in the oral vaccines.展开更多
基金supported in part by the Hubei Provincial Natural Science Foundation of China(grant no.2023AFA094)the Yingzi Tech&Huazhong Agricultural University Intelligent Research Institute of Food Health(No.IRIFH202209)+1 种基金Fundamental Research Funds for the Central Universities(Project 2662023PY005)the Hubei Hongshan Laboratory&Huazhong Agricultural University Start-up Fund.
文摘The rapid emergence and spread of colistin-resistant gram-negative bacteria has raised worldwide public health concerns,and phosphoethanolamine(PEtn)transferase modification-mediated colistin resistance has been widely documented in multiple gram-negative bacterial species.However,whether such a mechanism exists in the zoonotic pathogen Pasteurella multocida is still unknown.Recently,a novel PEtn transferase,PetL,was identified in P.multo-cida,but whether it is associated with colistin resistance remains to be elucidated.In this study,we found that PetL in P.multocida(PetL^(PM))exhibited structural characteristics similar to those of the mobile-colistin-resistant(MCR)protein and the PEtn transferase characterized in Neisseria meningitidis.The transformation of petLPM into E.coli or K.pneumoniae changed the phenotype of several tested strains from colistin sensitive to colistin resistant.Deletion of this gene decreased the colistin minimum inhibitory concentration(MIC)of P.multocida by 64-fold.Our extensive analysis by MALDI-TOF-MS demonstrated that PetLPM participated in the modification of bacterial lipopolysaccharide(LPS)-lipid A.Deletion of petL^(PM) led to an increase in membrane charge but a decrease in cell-surface hydrophobicity and cell permeability in P.multocida.The present study is the first to report the presence of PEtn transferase-mediated colistin resistance in the zoonotic pathogen P.multocida.
基金supported by the National Natural Science Foundation of China(31302109)
文摘Pasteurella multocida, a Gram-negative nonmotile coccobacillus, is the causative agent of fowl cholera, bovine hemorrhagic septicemia, enzoonotic pneumonia and swine atropic rhinitis. Two filamentous hemagglutinin genes, fhaB1 and JhaB2, are the potential virulence factors. In this study, an inactivationfhaB1 mutant ofP. multocida in avian strain C48-102 was constructed by a kanamycin-resistance cassette. The virulence of thefhaB1 mutant and the wild type strain was assessed in chickens by intranasal and intramuscular challenge. The inactivation offhaB1 resulted in a high degree of attenuation when the chickens were challenged intranasally and a lesser degree when challenged intramuscularly. ThefhaB1 mutant and the wild type strain were investigated their sensitivity to the antibody-dependent classical complement-mediated killing pathway in 90% convalescent chicken serum. ThefhaB1 mutant was serum sensitive as the viability has reduced between untreated serum and heat inactivated chicken serum （P〈0.007）. These results confirmed that FhaB1 played the critical roles in the bacterial pathogenesis and further studies were needed to investigate the mechanism which caused reduced virulence of the fhaB1 mutant.
基金funded by the subproject of National Key Technology R&D Program(2006BAD06A01 and 2006BAD06A12)Basic Work of National Science and Technology Special Plan(2008FY210200)
文摘[Objective]To develop multiplex-PCR for diagnosis of mixed infection caused by Pasteurella multocida(PM),Haomophilus parasuis(HPS)and Actinbaci/lus pleuropneumoniae(App).[Method]PCR method was developed to detect single infection caused by PM,HPS or App.The conditions of amplification and primers were optimized,and the multiple-PCR was developed to detect mixed infection of PM,HPS and App.[Result]A 457-bp band,a 821-bp band and a 342-bp band were simultaneously amplified in the one PCR reaction system.The method had high sensitivity and specificity.[Conduslon]The multiple-PCR is successfully developed and can be used for differential diagnosis of PM,HPS and App.
文摘Animal bites are frequently encountered in the emergency department(ED). Aortitis leading to mycotic abdominal aortic aneurysm is a rare and potentially deadly complication of Pasteurella multocida(P. multocida) following an animal bite. We present the case of a 68-year-old male who presented to the ED after falling at home. He complained of weakness and abdominal pain. He was in septic shock and was treated empirically with broad-spectrum antibiotics and intravenous fluids. He reported previous antibiotic treatment of a cellulitis secondary to a cat bite injury to his right thumb four weeks prior. Abdominal ultrasound and subsequent computed tomography scan revealed a leaking mycotic abdominal aneurysm that was surgically repaired. Blood cultures and aortic wall tissue cultures grew P. multocida. Given how common animal bite presentations are in the ED, this case highlights the need to consider aortitis and mycotic abdominal aortic aneurysm in an unwell patient with an animal bite.
文摘Respiratory diseases are one of the most important health problems in pig herds. The porcine respiratory disease complex (PRDC) is the term used to describe pneumonic diseases caused by multiple infectious agents that provoke weight loss in animals or death. In the PRDC multiple pathogens (bacteria and/or viruses) work in combination to induce this respiratory disease. Within this complex, Actinobacillus pleuropneumoniae, Streptococcus suis, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis and Mycoplasma hyopneumoniae are the main bacterial pathogens involved in great economic losses to the swine industry. The aim of this work was to estimate the presence of A. pleuropneumoniae, S. suis, P. multocida, B. bronchiseptica, H. parasuis and M. hyopneumoniae in the upper respiratory tract of pigs in representative swine farms inAguascalientes,Mexico, using PCR technique. The study was performed in 14 swine farms. We obtained a total of 212 nasal swabs. Near 20% of samples were positive for A. pleuropneumoniae (located in the 79% of farms);17% were positive for S. suis (in 86% of farms), of these, 3% were S. suis serovar 2;30% were positive for H. parasuis (93% of farms);23% of the samples to P. multocida (in 79% of farms);and 19% to M. hyopneumoniae (in 64% of farms). B. bronchiseptica was not detected in this study. The results obtained show that bacterial pathogens of PRDC were present in the upper respiratory tract of pigs in all farms studied;therefore, these pathogens are widely disseminated in pig farms of Aguascalientes, Mexico.
文摘Pasteurella species is considered the principal pathogen of the respiratory tract.Mannheimia haemolytica and Pasteurella multocida were investigated and typed from nasal swabs and tissues taken from sheep,goat and cattle.Indeed,41 lung and 121 nasal swabs samples were collected from animals with respiratory diseases during 2015 to 2017 in six different regions in Morocco.At first,a screening of Pasteurella species using the real time PCR(RT-PCR)was carried out,then all isolated strains on agar blood were confirmed by PCR gel based assay specific for M.haemolytica and P.multocida.Pathogenicity was evaluated in mice and histopathological examination was done on some of lung tissue.The results revealed that 34 samples of which 28(55%)from nasal swabs and six(38%)from lungs were positive for M.haemolytica and nine samples of which seven(14%)from nasal swabs and two(13%)from lungs were positive on P.multocida serogroup A.Seventy-two percent(72%)isolates were highly pathogenic to mice,which is in accordance with the results obtained by histopathology examination.This is the first report for widespread infections of Pasteurella(M.haemolytica&P.multocida)in ruminants in Morocco.Therefore,measures including development of vaccines are highly required to mitigate the impact of the bacteria in animals.
基金This work was supported in part by the China Postdoctoral Foundation(grant 2020 T130232)the Key Laboratory of Livestock Disease Prevention of Guangdong Province and the Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province,Ministry of Agriculture and Rural Affairs,China(grant YDWS1901)Hubei Provincial Key R&D program.The funder had no role in the study design,data collection,data analysis,data interpretation,or writing of the manuscript.
文摘Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve this,we briefly investigated 158 P.multocida isolates from pigs with respiratory disorders in China between 2019 and 2020.Genotyping through multiplex PCR assays assigned these 158 isolates into capsular genotypes A(60.13%,95/158),D(35.44%,56/158),F(4.43%,7/158),and/or lipopolysaccharide(LPS)genotypes L3(28.48%,45/158)and L6(66.46%,105/158).In addition,eight isolates(5.06%,8/158)were found to be nontypable using the LPS genotyping method.When combining the capsular genotypes and the LPS genotypes,D:L6(34.81%,55/158)and A:L6(31.65%,50/158)were the predominant genotypes,followed by A:L3(24.05%,38/158).PCR detection of virulence factor-encoding genes showed that over 80%of the isolates were positive for exbB,tonB,exbD,ompH,ptfA,fimA,sodA,sodC,fur,ompA,oma87,plpB,hsf-2,nanH and hgbB,suggesting the presence of these genes were broad characteristics of P.multocida.We also found approximately 63.92%(101/158),51.27%(81/158),8.86%(14/158),7.59%(12/158),3.16%(5/158),0.63%(1/158),and 0.63%(1/158)of the isolates grew well in media with the presence of colistin(4μg/mL),tetracycline(16μg/mL),tigecycline(1μg/mL),ampicillin(32μg/mL),chloramphenicol(32μg/mL),cefepime(16μg/mL),and ciprofloxacin(1μg/mL),respectively.This study contributes to the understanding of genotypes and antimicrobial resistance profile of P.multocida currently circulation in pigs of China.
基金Supported by Regular goveromental annual fund every Fiscal year from Assiut university(Grant No.9/020/08595/0)
文摘Objective:To characterize Pasteurella isolated from backyard chickens using whole cell protein lysate profiles and random amplified polymorphic DNA(RAPD)techniques to show their genetic relationship because Pasteurclla multocida(P.multocida)is an important cause of fatal infections in backyard chickens.Methods:Twenty one P.multocida isolates were recovered previously from clinical cases of fowl cholera belonging to individual owners and phenotypically analysed using biochemical tests and serotyping were used far the genetic characterization.Results:Phylogenetic study based on both methods revealed that the recovered population of P.multocida isolated from backyard chickens differs markedly,constituting a well-separated cluster and appearance of 3 distinguishing lineages with greater discrimination shown by RAPDPCR that resulted in two suclusters in cluster A and three subclusters in cluster B and were related greatly with capsular serogroups for the examined strains.The whole cell protein revealed the presence of dominant protein bands at approximately 41 and 61 kDa in all of the examined isolates that may be a virulent proteins share in the increasing of its pathogenicity.Clear distinctive bands ranged from 123 to 1534 bp.Conclusions:Based on the previous findings,there are three spreading clusters that may indicate the association of a small number of P.multocida variants with the majority of cases suggesting that certain clones of P.multocida are able to colonue the examined backyard chickens.Also,the ease and rapidity of RAPD-PCR support the use of this technique as alternative to the more labour-intensive SDS-PACE system for strain differentiation and epidemiological studies of avian P.multocida.Further application of RAPD technology to the examination of avian cholera outbreaks in commercially available flocks may facilitate more effective management of this disease by providing the potential to investigate correlations of P.multocida genotypes,to identify affiliations between bird types and bacterial genotypes,and to elucidate the role of specific bird species in disease transmission.
文摘The control and prevention of pasteurellosis in rabbits which makes the hosts unsuitable for experimental use raised the needs to improve and simplify the procedures of Enzyme-Linked Immunosorbent Assay (ELISA) for detect of antibody against P.multocida. A comparison on the sensitivity and specificity of bacterial culture of antemortem and postmortem samples, complement fixation test and enzyme-linked immunosorbent assay of 11 apparently healthy adult rabbits was conducted. The incidence rates showed 45.45%,54.54% and 72.73% respectively. The sensitivity for the three methods were 0.63, 0.67,and 1.00,and specificity for them were 1.00, 0.67 and 1.00 respectively. Somatic serotypes of isolates of P.multocida from rabbits of three groups (rabbits of group 2 were with clinic signs, those of groups 1 and 3 were apparently healthy) revealed no remarkable differences,and the predominant types were type 3 and type 3, 4. This was somewhat different from the reports derived from other states. As the antigen of different serotype used in ELISA may have different sensitivity and specificity, which is affected also by different preparation method, a type non-specific antigen should be selected to meet such request. The trial of accomplishment of ELISA without positive and negative controls was presented for discussion.
基金part of the project:Study on immune response pattern of cattle vaccinated by Razi pasteurellosis vaccine(Project number:12-18-18-9458-94014)
文摘Objective:To evaluate the effects of Pasteurella multocida(P.multocida)vaccines on the expression and release of antibodies,interleukin(IL)-6 and IL-12 by serum.Methods:Balb/c mice were immunized with two formalin and iron inactivated vaccine doses within 2 weeks.The vaccines were adjuvant with P.multocida A strain,P.multocida B strain and Salmonella typhimurium bacterial DNA(AbDNA,BbDNA and SbDNA for short,respectively).The animals were challenged 4 weeks after immunization.Blood of mice was collected to detect the change of specific antibody,IL-6,and IL-12 using ELISA.Results:The specific antibody and interleukins in the immunized group increased significantly compared to the control mice after vaccination and challenge(P<0.05).The highest release of these cytokines was obtained by P.multocida inactivated with iron and adjuvant with AbDNA at a concentration of 25μg/mL.The antibody titer peak was 0.447 in mice vaccinated with iron-killed whole-cell antigen adjunct with AbDNA.The time-courses of release showed that bacterial DNA was able to stimulate IL-6 and IL-12 production more than alum(P<0.05).Conclusions:Our findings introduce that bacterial DNA is capable of releasing an immunological response with several cytokines.These indicate that bacterial DNA entrapped with killed P.multocida antigen is a new and effective adjuvant to enhance specific immunity and resistance of animal against the infectious pathogen,which could simplify the development of highly promising strong adjuvant.
基金Supported by the Hongkong Fok Ying Tung Ming Yuan Fund(HK314-14591)Guangdong Provincial Agricultural Research Projects(2004B20201019)Shaoguan Science and Technology Innovation Projects(2010140473)
文摘[Objective] To study on genetic inactivation bacterial ghosts of Pasteurella multocida based PhiX174 gene E lysis cassette mediated. [ Method ] Recombinant pPBA1100-e was constructed by which the gene E of bacteriophage Phix174 and temperature sensitivity expressing control system hybridized with plasmid pPBA1100 by genetic engineering method. Recombinant was transformed to Pasteurella multocida and lysis gene E expressed by temperature induction. Recombinant was detected by restriction endonuclease. Cell morphology of bacterial ghost of Pasteurella mul- tocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysis. I Result~ The results indicated that the recombination plasmid presented three bands by restriction endonuclease and agarose electrophoresis and that molecular weight of every band ac- corded with theoretical value. The result of SEM observing showed that recombination plasmid expressed successfully in P. multocida and produced bacterial ghost. The result of CFU detecting demonstrated that inactivation ratio of P. multocida reached 99 per cent. ~Conclusion~ This study pro- vided technical bases for the preparation of antigen vaccine of natural bacterial outer membrane protein.
文摘Pasteurellosis is the most prevalent, extremely contagious bacterial disease among domestic rabbits and is considered the leading cause of deaths in rabbits, resulting in enormous economic losses to the rabbit industry. Screening for bacterial agents causing mortalities in rabbits revealed the presence of Enterobacteriacae species in approximately 42% of studied cases, with E. coli the most commonly isolated organism. The present study was designed to evaluate the immune response of rabbits vaccinated with a locally prepared, combined inactivated vaccine of Pasteurella multocida and E. coli, adjuvanated with Montanide ISA70. A total of 370 rabbits, aged 2 - 3 weeks, were divided into four groups: (G1) vaccinated with a polyvalent P. multocida vaccine, (G2) vaccinated with a polyvalent E. coli vaccine, (G3) vaccinated with a combined inactivated Montanide ISA70 vaccine of P. multocida and E. coli, and (G4) kept as a non-vaccinated control group. All rabbits received two doses of 0.5 ml of the prepared vaccines, administered one month apart, and were then challenged with virulent strains of P. multocida and E. coli three weeks after the second vaccination. The prepared vaccines were evaluated by determining humoral immunity using indirect haemagglutination (IHA) test and ELISA. The potency of the vaccines was assessed through challenge and determination of LD50. Experimental findings on the prepared polyvalent combined inactivated P. multocida and E. coli vaccine indicated that it is a potent vaccine, producing the highest antibody titers and a 90% protection rate against challenges with virulent strains of P. multocida type A, D2, and E. coli types O157, O151 and O125. Thus, this vaccine is promising in addressing both P. multocida and E. coli problems in rabbits, farms, providing significant protection, and we recommend its commercial production to help rabbit producers control these two major bacterial infections.
文摘In this study,55 suspected pasteurellosis clinical cases from different provinces of Morocco were investigated.Molecular analysis revealed that 47%of samples were positive for Pasteurella multocida,all typed as serogroup A,and 11%positive for Mannheimia heamolytica.Eight isolates were recovered from 26 P.multocida positive samples,and characterized by biochemical and molecular typing methods.Among these isolates,two strains(S13 and S14)were selected for genes(RNA16S and rpoB)sequence analysis and virulence study in mice,guinea pigs and sheep.Phylogeny study showed similarities of both S14 and S13 isolates with strains from other species.In laboratory animals,the strain S14 was more virulent than S13 and induced severe illness in sheep.The high mortality of infected mice suggests that this model may represent an alternative for testing pathogenicity and vaccine efficacy.
文摘<strong>Background:</strong> This work evaluated the capacity of a dry emulsion as a carrier of viable microorganisms with potential use as prophylaxis of infectious diseases. <strong>Methods:</strong> The aqueous phase containing <em>P. multocida </em>not viable in PBS was emulsified in mineral oil to obtain a w/o emulsion. The microorganisms remained stable and only in two cases (n = 6) did the bacterial concentration decrease. Scanning Electron Microscopy (SEM) revealed a structure of a system with the organized association of particles with cubic symmetry. Using two <em>ex vivo </em>bioadhesion systems, it was demonstrated that the disperse-adsorbed system is capable of adhering to the intestinal mucosa and remains adhered for long periods of time. <strong>Results: </strong>The no viability of the bacteria in the dry emulsion and the possibility of controlled release were confirmed. <em>In vivo </em>trial was conducted in pigs. It was possible to locate the emulsion and the bacteria attached to the gut of the living animal. An ELISA kit was used to monitor the mean antibody titer of treated pigs over a 2-week period, and a classic primary response curve occurred when the titer was plotted against time. <strong>Conclusion: </strong>We propose the disperse-adsorbed system as an alternative to commonly used vehicles for immunogens in the oral vaccines.
