The dose regimen formulation of doxycycline hydrochloride and florfenicol injection based on ex vivo pharmacokinetic-pharmacodynamic modeling against the Actinobacillus pleuropneumoniae in pigs

Doxycycline hydrochloride and florfenicol combination(DoxHcl&FF)is an effective treatment for respiratory diseases.In the study,our objective Was to evaluate the activity of DoxHcl&FF against Actinobacillus pleuropneumoniae(APP)in porcine pulmonary epithelial lining fluid(PELF)and the optimal dosage scheme to avoid the development of resistance.The DoxHcl&FF Was administered intramuscularly(IM)at 20mg/kg,and the PELF was collected at differ-ent time points.The minimum inhibitory concentration(MIC)and time-mortality curves were also included in the study.Based on the sigmoid Emax equation and dose equations,the study integrated the in vivo pharmacokinetic data of infected pigs and ex vivo pharmacodynamic data to obtain the area under concentration time curve(AUCo-24h)MIC values in PELF and achieve bacteriostatic activity,bactericidal activity and the virtual eradication of bacteria.The study showed that the combination of DoxHcl and FF caused no significant changes in PK parameters.The peak concentration(Cmax)of FF in healthy and diseased pigs was 8.87±0.08 and 8.67±0.07μg/mL,the_AUCo-24h were.172.75±2.52 and 18022±3.13 h-μg/mL,the Cmax of DoxHcl was 7.91±0.09 and 7.99±0.05μg/mL,and the AUCo-24h was 129.96±3.70 h-μg/mL and 169.82±4.38 h-μg/mL.DoxHcl&FF showed strong concentra-tion-dependent tendencies.The bacteriostatic,bactericidal,and elimination activity were calculated as 5.61,18.83 and 32.68 h,and the doses were 1.37(bacteriostatic),4.59(bactericidal)and 7.99(elimination)mg/kg.These findings indicated that the calculated recommended dose could assist in achieving more precise administration,increasing the effectiveness of DoxHcl&FF treatment for APP infections.

Epidemiological Investigation of Actinobacillus Pleuropneumoniae in Western Shandong

[ Objective ] The aim of this study was to investigate the epidemic status of porcine pleuropneumonia in western Shandong and establish the PCR method of actinobacillus pleuropneumoniae （APP）. [ Method] The epidemic status of APP in lesion tissues of 186 death pigs and 545 health pigs without clinical symptoms was analyzed by PCR method. [ Result] APP positive rate in 186 samples accounted for 43.0% （80/186）, while that in 545 porcine serums accounted for 9.4% （51/545）. [ Conclusion] This PCR method can be used as one of the important means for APP clinical diagnosis.

Establishment of an Indirect ELISA with the Major Epitope Domain of ApxⅡ of Actinobacillus pleuropneumoniae Expressed in Prokaryotic Cells

[Objective] This study aimed to develop an indirect ELISA to detect the antibodies against Actinobacil us pleuropneumoniae （APP） using the recombinant ApxⅡA1 protein expressed in prokaryotic cells as the antigen. [Method] The major epi-tope domain of ApxⅡ was cloned into the prokaryotic expression vector pET-28a （＋） to obtain the recombinant plasmid pET-ApxⅡA1, which was then transformed into E. coli BL21 （DE3） for expression. The immunogenicity of the recombinant pro-tein was analyzed by western-blotting. After that, the purified recombinant protein was used as the coating antigen in the indirect ELISA for detecting the antibodies against APP. Final y, the concentration of coated antigen and the dilution of serum were optimized. [Result] Proved by enzyme digestion and sequencing, the recombi-nant plasmid pET-ApxⅡA1 was constructed successful y. The recombinant protein was highly expressed in prokaryotic cells, and Western-blotting analysis showed that it was recognized specifical y by positive serum of APP. The indirect ELISA could detect the antibody against APP with the purified recombinant protein as the coating antigen. The optimal concentration of coated antigen was 1.23 μg/ml and the opti-mal dilution of serum was 1：100. Compared with a commercial ELISA kit detecting antibody against ApxⅣ, the coincidence rate of the indirect ELISA was 90.4%. [Conclusion] Our results indicated that the indirect ELISA is sensitive and specific, and suitable for evaluating the effect of APP vaccine and epidemiological surveys.

Identification and Detection of Actinobacillus pleuropneumoniae in Infected and Subclinically Infected Pigs by Multiplex PCR Based on the Genes ApxIVA and OmlA

PCRs based on different genes of Actinobacillus pleuropneumoniae have been developed for detecting and identifying A. pleuropneumoniae. Some of them could amplify positive fragments from the phylogenetically closely related species bacteria. To improve veracity and specificity of PCR, a species-specific multiplex PCR assay was developed to identify and detect A. pleuropneumoniae, based on the 3＇-terminus of the species-specific apxlVA gene and the already existing species-specific primers in the omlA gene. Both 346-bp and 950-bp fragments could be simultaneously amplified from all A. pleuropneumoniae reference strains and isolates, and the species specificity of the assay was evaluated with a collection of ten strains representing eight different species bacteria including species normally found in the respiratory tracts of swine. All of these strains turned out negative in the multiplex PCR. All sequences of products of multiplex PCR randomly sampled were also correct. The sensitivity of the multiplex PCR was determined to be 10 pg of A. pleuropneumoniae DNA. The multiplex PCR and bacterial isolation were compared to determine their sensitivities by using experimentally infected pigs and clinical disease pigs. The multiplex PCR was more sensitive than bacterial isolation. The multiplex PCR was also evaluated on mixed bacterial cultures from clinical healthy pigs. 26/100 （26%） of the subclinically infected pigs were detected from clinical healthy pigs. The results indicate that the multiplex PCR assay is a sensitive, highly specific, and effective diagnostic tool for identification and detection of A. pleuropneumoniae.

Cloning, Expression of apxl Gene of Actinobacillus pleuropneumoniae and Development of ELISA

Based on the published nucleotide sequence of the apxICA of Actinobacillus pleuropneumoniae in Genbank(S4074), a pair of primers were designed. A 3 640 bp(4 687 - 8 326 bp)gene fragment was amplified by PCR from the isolated strain of A. pleuropneumoniae serovar 1. Then, it was cloned into pMD18-T, identified by both restriction endonuclease and sequence analysis, and inserted into pET-28a expression vector to yield the expression plasmid. SDS-PAGE result indicated expression of apxICA in BL21 (DE3), Western blot analysis showed the protein's immunogenicity. Using the expressed protein, ELISA was established to detect serum antibody against ApxI. The feature of ELISA to detect highly virulent A. pleuropneumoniae strains infection was proved by primary clinical application.

In Vitro Activity and Postantibiotic Effect of Tulathromycin against Actinobacillus pleuropneumonia

The postantibiotic effect （PAE） is defined as the suppression of bacterial growth persisting after a short exposure of bacterial cultures to an antibiotic. This phenomenon has obvious clinical interest, because antibiotic agents which produce extensive PAEs could be administrated less frequently without reducing efficacy. The minimum inhibitory concentration （MIC） and PAE of tulathromycin and erythromycin on five isolates of Actinobacillus pleuropneumonia were determined. All strains were susceptible to tulathromycin （ MIC： 0.25 - 1.00 μg/ml） and resistant to erythromycin （MIC： 32 -128 μg/ml）. The mean PAEs of 1 xMIC, 2 xMIC, 4 xMIC and 8 xMIC of tulathromycin against the tested isolates were 0.62, 1.53, 2.70 and 4.50, respectively. These results indicated that tulathromycin might be administered at longer time intervals than those already applied. This is in tavorite of the clinical rational use of antimicrobial druqs.

Presence of <i>Actinobacillus pleuropneumoniae, Streptococcus suis, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis and Mycoplasma hyopneumoniae</i>in upper respiratory tract of swine in farms from Aguascalientes, Mexico

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.

ArcA Gene Expression Level of Actinobacillus pleuropneumoniae in Anaerobic Culture

In the present study,mRNA levels of the ArcA gene of Actinobacillus pleuropneumoniae serotype1 were measured during response to stress by growing under anaerobic conditions.Expression levels were measured by semi-quantitative RT-PCR using the housekeeping gene recF as an internal standard.The expression of ArcA was undetectable until about 3 hours under standard culture conditions,but it was promptly and highly expressed in anaerobic culture.The results are consistent with ArcA being a potential virulence gene of Actinobacillus pleuropneumoniae,and likely playing an important role in pathogenesis caused by this organism.

Cloning and Expression of Actinobacillus pleuropneumoniae Gene Coding for TbpA and Development of an Indirect TbpA-ELISA

This study presents the cloning and expression of gene encoding transferrin-binding protein A from Actinobacillus pleuropneurnoniae in Escherichia coli expression system and the development of an indirect TbpA-ELISA. The gene coding TbpA was amplified from the A. pleuropneumoniae serotype 2 genome using polymerase chain reaction and cloned to pET-28b expression vector under the control of strong, inducible T7 promoter. The recombinant plasmid was expressed in E. coli BL21 （DE3）. The expressed fusion protein was analyzed using SDS-PAGE and Western blotting. The diagnostic potential of recombinant TbpA （rTbpA） was evaluated through an antibody-detection indirect ELISA based on the purified rTbpA. The TbpA antibodies were detectable in mice on day 7 after vaccination with purified rTbpA protein or infection with A. pleuropneumoniae serotype 10 with the TbpA-based ELISA. In addition, the TbpA-ELISA was able to detect 12 serotyping rabbit antisera postinoculation （PI） with A. pleuropneumoniae 12 serotypes experimentally. The comparable result was obtained by detecting the 117 clinical serum samples using, respectively, the TbpA-ELISA and indirect hemagglutination test （IHA） based on multiplex antigen. The result indicates that the TbpA-ELISA was the more sensitive method compared with the Mix-IHA method because of its consistent presence in A. pleuropneumoniae serotypes. In conclusion, the conserved TbpA of A. pleuropneumoniae can be used for the development of a cross-serotype diagnostic method for the detection of antibodies against A. pleuropneurnoniae.

Genetic Evolution Analysis of Actinobacillus pleuropneumoniae

In order to explore the genetic evolution of Actinobacillus pleuropneumoniae(App) in different countries and clarify the relationships among different App in each region, the 16 S rRNA gene of App in the NCBI nucleotide database was analyzed and compared by the bioinformatics method. The phylogenetic tree was constructed after tailoring alignment. The results showed that a stable genetic phenomenon was indicated in the evolutionary process of App. The isolates derived from China were clustered and showed a high degree of conservation. They had a certain genetic relationship with the British and American strains, but had far relationship with the strains from Japan which was a neighboring country of China. The isolates from different countries in the Eurasian continent shared high homology. The isolates of the two regions originated from common ancestors.

Rationally designed mariner vectors for functional genomic analysis of Actinobacillus pleuropneumoniae and other Pasteurellaceae species by transposon-directed insertion-site sequencing (TraDIS)

Comprehensive identification of conditionally essential genes requires efficient tools for generating high-density transposon libraries that, ideally, can be analysed using next-generation sequencing methods such as Transposon Directed Insertion-site Sequencing (TraDIS). The Himar1 (mariner) transposon is ideal for generating near-saturating mutant libraries, especially in AT-rich chromosomes, as the requirement for integration is a TA dinucleotide, and this transposon has been used for mutagenesis of a wide variety of bacteria. However, plasmids for mariner delivery do not necessarily work well in all bacteria. In particular, there are limited tools for functional genomic analysis of Pasteurellaceae species of major veterinary importance, such as swine and cattle pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida, respectively. Here, we developed plasmids, pTsodCPC9 and pTlacPC9 (differing only in the promoter driving expression of the transposase gene), that allow delivery of mariner into both these pathogens, but which should also be applicable to a wider range of bacteria. Using the pTlacPC9 vector, we have generated, for the first time, saturating mariner mutant libraries in both A. pleuropneumoniae and P. multocida that showed a near random distribution of insertions around the respective chromosomes as detected by TraDIS. A preliminary screen of 5000 mutants each identified 8 and 14 genes, respectively, that are required for growth under anaerobic conditions. Future high-throughput screening of the generated libraries will facilitate identification of mutants required for growth under different conditions, including in vivo, highlighting key virulence factors and pathways that can be exploited for development of novel therapeutics and vaccines.

猪传染性胸膜肺炎发病机制研究进展

猪传染性胸膜肺炎(porcine pleuropneumonia,PCP)是由猪胸膜肺炎放线杆菌(Actinobacillus pleuropneumoniae,APP)引起的一种严重呼吸道疾病,在全世界广泛流行。APP主要通过直接接触、气溶胶和污染物在猪群之间传播,猪只感染后,多种毒力因子触发一系列细胞因子级联反应,引发“炎症风暴”造成脓毒血症,导致肺脏病变及坏死,最急性型的死亡率可达80%~100%。PCP在我国的发病率呈逐年上升趋势,已成为危害养猪业最严重的疾病之一,给我国养殖业造成严重的经济损失。临床上常用抗生素治疗PCP,但由于细菌耐药性日益严重,使得抗生素对该病的防控愈发困难。此外APP血清型较多,不同类型血清型之间交叉免疫不强,导致疫苗防控效果不理想,感染后死亡率和发病率均处于上升趋势。目前,人们对APP发病机制的研究主要集中在毒力因子方面,关于该菌的侵袭过程(如细菌的定植和营养获取、逃避宿主防御、诱导组织损伤等)对PCP的发生、发展及预后的影响尚不清楚。因此,文章主要综述了PCP的发病机制,揭示了多种因素的作用,以期了解APP的感染过程及机体的免疫机制,在抗炎和增强免疫力等环节为防治PCP提供理论依据。

胸膜肺炎放线杆菌利用肠菌素摄取铁促生长的研究

肠菌素(Ent)介导的铁摄取系统在病原细菌生长和定植过程中发挥关键作用。胸膜肺炎放线杆菌是引起猪传染性胸膜肺炎的病原,为鉴定该菌不同血清型菌株能否利用肠菌素摄取铁发挥促生长作用,试验选用胸膜肺炎放线杆菌血清1~12型参考菌株,首先在限铁条件下通过肠菌素促生长试验鉴定不同血清型菌株能否利用肠菌素;进而通过添加不同浓度的铁螯合剂DFO、细菌接种量、肠菌素等因子,筛选胸膜肺炎放线杆菌利用肠菌素促生长的最适培养条件;最后分别在限铁和富铁培养条件下通过生长曲线鉴定肠菌素对胸膜肺炎放线杆菌12个血清型菌株的促生长作用。结果显示,在测定的胸膜肺炎放线杆菌血清1~12型参考菌株中,除血清2型和10型外,其他型菌株在限铁条件下均可利用肠菌素促生长。不同因子筛选结果显示,最适细菌接种浓度为1×10^(4)CFU/mL,添加DFO浓度为20μmol/L,而添加0.4、2.0、10.0μg/mL等不同浓度的肠菌素对胸膜肺炎放线杆菌均有显著促生长作用,且随肠菌素浓度升高而促生长能力显著增强。试验证实胸膜肺炎放线杆菌可利用肠菌素促进其生长,同时证实不同血清型利用肠菌素方面存在显著差异,为解析肠菌素介导的铁摄取系统在胸膜肺炎放线杆菌中的作用机制奠定了基础。

胸膜肺炎放线杆菌ApxⅠ蛋白单克隆抗体制备和抗原表位初步鉴定

为了制备胸膜肺炎放线杆菌(Actinobacillus pleuropneumoniae,APP)Ⅰ型ApxⅠ毒素(ApxⅠ)AI2蛋白特异性单克隆抗体,进而建立用于评估亚单位疫苗免疫效果的阻断ELISA方法,以实验室前期筛选得到的ApxⅠ抗原优势决定簇AI2重组蛋白为免疫原,免疫6周龄BALB/c雌鼠。利用常规细胞融合和间接ELISA筛选阳性杂交瘤细胞,获得4株单克隆抗体,命名为2C2、4E4、5E7和6F2,上清液效价分别为1∶6400、1∶6400、1∶12800和1∶6400。ELISA与Western blot结果表明,制备的4株单克隆抗体均与重组AI2蛋白有良好的反应性。其中5E7可与APP天然ApxⅠ毒素蛋白特异性结合,同时4株单克隆抗体均不与多杀性巴氏杆菌、支气管败血波氏菌、猪丹毒丝菌、副猪格拉菌和猪链球菌2型反应。亚类分型结果表明,2C2、4E4、5E7属于IgG1亚类,6F2属IgG2a亚类,4株单抗轻链均为κ链。通过构建AI2重组蛋白截短体,初步确定线性表位在74~93 aa之间。本研究成功制备了4株针对AI2蛋白单克隆抗体,为APP亚单位疫苗免疫效果评估方法的建立奠定了基础。

猪胸膜肺炎放线杆菌(APP)1型感染小鼠模型的建立及其病理学观察

为了针对我国目前流行菌株猪胸膜肺炎放线杆菌1型(App-S1)菌进行致病性研究,同时成功建立实验动物感染模型并完成病理学观察。本实验选取25只昆明小鼠随机均分为5组,4个试验组分别腹腔注射4×104、4×105、4×106、4×107 cfu/mL的App-S1菌液1mL/只,对照组注射生理盐水1mL/只。不同浓度菌液攻毒的小鼠3d内出现不同的临床表现,部分小鼠出现典型的肺炎、心外膜炎等症状并伴随有死亡现象。其证明了App-S1对实验动物昆明小鼠具有致病性,同时经计算得出了App-S1对昆明小鼠的LD50为4.48×105.85cfu/mL。将死亡小鼠进行剖检,选取病灶组织器官、分离细菌并经PCR鉴定为与攻毒App-S1相同的阳性菌株,同时制作切片,进行病理学观察分析。这些结果表明App-S1腹腔接种SPF级昆明小鼠可以复制出典型的胸膜肺炎病例,同时能够成功地人为构建实验动物感染模型,对今后App-S1致病性及其临床诊断方面的研究具有借鉴意义。

SS-HPS-APP三联亚单位疫苗对小鼠保护效果的评价

为评价猪链球菌病-副猪嗜血杆菌病-猪传染性胸膜肺炎三联亚单位疫苗(下称三联苗)对小鼠的保护效果,本研究将猪链球菌(SS)保护性抗原EF和猪胸膜肺炎放线杆菌(APP)保护性抗原OMP、ApxI、ApxII序列分别克隆至pET-28a和pCold-sumo载体,再转化至E.coli BL21(DE3)中构建重组菌,经过诱导表达纯化获得重组蛋白r EF、rOMP、rApxI和rApxII。利用本研究室前期构建的pET-28a-sly/BL21、pET-28a-mrp/BL21、pET-28aoppa/BL21、pET-28a-oppa2/BL21、pET-28a-afua/BL21、pET-22b-cdtb/BL216株重组表达菌株,表达纯化SS的rSLY、rMRP和副猪嗜血杆菌(HPS)的r OPPA、rOPPA2、rAfuA、rCdtB。将上述重组蛋白等量混匀,使每一剂疫苗中各蛋白的含量均为20μg,再与ISA 201佐剂乳化制成三联苗。将血清2型SS(SS2)464株和SS9 GZ2株按照不同比例稀释后感染C57小鼠;将血清5型HPS(HPS5)HN10株、HPS13 ZD12株、血清5型APP(APP5)MD株和APP7 S-8株按照不同比例稀释后感染BALB/c小鼠,统计上述6个菌株对小鼠的最小致死剂量(MLD)。将20只C57小鼠和40只BALB/c小鼠均分成2组(每组含10只C57小鼠和20只BALB/c小鼠),间隔14 d分别皮下免疫2次300μL PBS+ISA 201佐剂和三联苗。二免后14 d采集小鼠血清,通过间接ELISA检测各组小鼠的EF、MRP、SLY、OPPA、OPPA2、CdtB、AfuA、OMP、ApxI和ApxII的抗体水平。首免后28 d,将C57小鼠再按照免疫组别平均分为2组,分别以MLD的SS2和SS9攻菌;同理,将BALB/c小鼠再平均分为4组,分别以MLD的HPS5、HPS13、APP5和APP7攻菌。结果显示:SS2和SS9对C57小鼠的MLD均为5×10^(7)cfu/只,HPS5、HPS13、APP5和APP7对BALB/c小鼠的MLD分别为1.5×10^(8)cfu/只、5×10^(7)cfu/只、1.5×10^(8)cfu/只和7.5×10^(8)cfu/只。与免疫前相比,二免后14 d实验组小鼠体内对EF、SLY、MRP、OPPA、OPPA2、CdtB、AfuA、OMP、ApxI和ApxII的抗体水平显著升高(p<0.0001),对照组小鼠体内对10种抗原的抗体水平均无差异;实验组与对照组二免后抗体水平差异显著(p<0.0001)。攻菌实验中,对照组小鼠在观察期内全部死亡,攻菌SS2、SS9、HPS5、HPS13、APP5和APP7的实验组小鼠存活率分别为100%(5/5)、80%(4/5)、60%(3/5)、80%(4/5),80%(4/5),100%(5/5),对照组和实验组的存活率有显著差异(p<0.05)。以上结果表明该三联苗对SS2、SS9、HPS5、HPS13、APP5和APP7攻击的小鼠能够提供良好的交叉保护性。本研究首次系统研究并证实了该三联苗的免疫保护结果较好,为其进一步研究及应用提供了实验依据。

装载温控双基因裂解质粒的App菌影检测方法研究

为了提高对前期试验中制备的胸膜肺炎放线杆菌(App)菌影的检测效率,试验通过形态学鉴定、电镜扫描、PCR鉴定和间接ELISA法对App及其菌影进行检测。结果表明:PCR检测方法特异性显著,可检测AppⅠ、pMC-WK AppⅠ及其裂解情况,具有准确、灵敏、容易操作等优点。说明将菌影的形态学检查、电镜扫描、PCR和血清学检测相结合,可准确检验试验中不同阶段的App及其菌影。

胸膜肺炎放线杆菌ApxⅡ蛋白重组腺病毒载体构建及免疫原性研究

研究旨在构建胸膜肺炎放线杆菌ApxⅡ蛋白的复制缺陷型5型腺病毒载体的重组腺病毒。构建包含胸膜肺炎放线杆菌ApxⅡ基因的穿梭质粒pDC316-APXⅡ,并与腺病毒骨架质粒pBHGlox(delta)E13Cre共转染Hek293细胞,获得了重组腺病毒rAd-APXⅡ,将纯化后的重组腺病毒rAd-APXⅡ肌肉注射小鼠进行免疫原性分析。结果显示,试验成功构建了pDC316-APXⅡ质粒以及包装了rAd-APXⅡ病毒。rAd5-Null组未产生特异的APXⅡIgG抗体;低和高浓度rAd-APXⅡ组均可产生较高的APXⅡIgG抗体,其中高浓度组产生的抗体水平显著高于低浓度组(P<0.05);某疫苗组产生的抗体水平显著高于rAd-APXⅡ低浓度组(P<0.05),但低于rAd-APXⅡ高浓度组(P<0.05)。低、高浓度rAd-APXⅡ组和疫苗组的IgG1、IgG2a、IgG2b和IgG3抗体显著高于rAd-Null组(P<0.05);高浓度rAd-APXⅡ组和疫苗组抗体显著高于低浓度rAd-APXⅡ组(P<0.05)。研究表明,rAd-APXⅡ重组腺病毒免疫小鼠能够产生特异性抗体并显示良好的免疫原性。

猪胸膜肺炎杆菌免疫机制研究进展

猪传染性胸膜肺炎由胸膜肺炎放线杆菌(App)感染引起,影响猪的呼吸系统,死亡率高,在世界范围内造成猪业的重大经济损失。临床研究发现,部分野生株App对于常规抗生素具有耐药性,这为该病的防治带来严峻的挑战。本文梳理了近年来App感染过程中宿主免疫应答方面的相关研究,从先天性免疫、体液免疫和细胞免疫3个方面,探讨该菌的感染机理和免疫原性,以期为猪传染性胸膜肺炎的防控和疫苗研究提供参考。

猪传染性胸膜肺炎病例报告

为了确诊猪场1例疑似猪传染性胸膜肺炎的病例,本试验首先对该猪死亡前的临床症状进行了解,然后对死亡猪进行剖检并利用收集的病料进行细菌分离培养、质谱分析、PCR检测和组织病理学等实验室诊断。结果显示,该猪死亡前表现出体温升高、呼吸窘迫和鼻内流出血色样泡沫分泌物等临床症状,剖检发现胸腔积液、肺脏出血和肿大等病理变化。实验室诊断结果显示,胸腔积液、血液和肺脏等病料中分离获得的菌株为血清型7型胸膜肺炎放线杆菌。组织病理学观察结果显示,肺脏组织表现为出血性纤维素性肺炎,肺泡渗出液中可见蓝染的菌团;心脏、肾脏、淋巴结、肝脏和脾脏等其他脏器均有不同程度的出血、淤血、水肿和淋巴细胞浸润等组织病理学变化。综合以上诊断结果,确诊该猪为猪胸膜肺炎放线杆菌感染。