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Research in Microbiology Oct 2000A PCR-based procedure for detection and serotype identification of Actinobacillus pleuropneumoniae strains was developed and evaluated. The A. pleuropneumoniae tbpA and...
A PCR-based procedure for detection and serotype identification of Actinobacillus pleuropneumoniae strains was developed and evaluated. The A. pleuropneumoniae tbpA and tbpB genes were used as targets for amplification of DNA fragments, with a pair of specific primers for each gene. Amplification with tbpA primers rendered a 2.8-kb PCR product from all 12 A. pleuropneumoniae reference strains as well as from Actinobacillus suis strain CCM 5586, while amplification of a 1.9-kb PCR product was observed when testing ten Haemophilus parasuis strains of different serovars. Amplification of the tbpB gene from A. pleuropneumoniae serotypes 1, 6, 8 and 12, and A. suis CCM 5586 rendered an identical 1.8-kb fragment, while from A. pleuropneumoniae serotypes 2, 3, 4, 7, 9, 10 and 11, and H. parasuis strains it produced a 1.7-kb fragment. No PCR amplification product was observed when examining strains of 19 other swine pathogens or closely related species. The minimal detection limit for whole-cell A. pleuropneumoniae templates was between 5-50 and 3 x 10(2)-3 x 10(3) CFU when tbpA and tbpB specific primers, respectively, were used. Restriction fragment length polymorphism (RFLP) analysis of the PCR-generated products rendered different patterns, easily allowing us to discriminate between A. pleuropneumoniae, H. parasuis and A. suis and, more importantly, to distinguish ten RFLP A. pleuropneumoniae groups (the highest discrimination reported so far for a PCR assay with A. pleuropneumoniae), in such a way that the only serotypes with profiles identical to each other were 4 to 11 and 7 to 9. Moreover, the PCR-RFLP analysis was assayed in 36 A. pleuropneumoniae field isolates and in porcine samples (lungs and nasal swabs from experimentally infected animals). In both cases the system proved to be very efficient in A. pleuropneumoniae identification and serotype discrimination.
Topics: Actinobacillus pleuropneumoniae; Animals; Carrier Proteins; Iron-Binding Proteins; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Swine; Transferrin-Binding Proteins
PubMed: 11081581
DOI: 10.1016/s0923-2508(00)00135-2 -
Veterinary Research 2003Equine Actinobacillus species were analysed phylogenetically by 16S rRNA gene (rrs) sequencing focusing on the species Actinobacillus equuli, which has recently been...
Equine Actinobacillus species were analysed phylogenetically by 16S rRNA gene (rrs) sequencing focusing on the species Actinobacillus equuli, which has recently been subdivided into the non-haemolytic A. equuli subsp. equuli and the haemolytic A. equuli subsp. haemolyticus. In parallel we determined the profile for RTX toxin genes of the sample of strains by PCR testing for the presence of the A. equuli haemolysin gene aqx, and the toxin genes apxI, apxII, apxIII and apxIV, which are known in porcine pathogens such as Actinobacillus pleuropneumoniae and Actinobacillus suis. The rrs-based phylogenetic analysis revealed two distinct subclusters containing both A. equuli subsp. equuli and A. equuli subsp. haemolyticus distributed through both subclusters with no correlation to taxonomic classification. Within one of the rrs-based subclusters containing the A. equuli subsp. equuli type strain, clustered as well the porcine Actinobacillus suis strains. This latter is known to be also phenotypically closely related to A. equuli. The toxin gene analysis revealed that all A. equuli subsp. haemolyticus strains from both rrs subclusters specifically contained the aqx gene while the A. suis strains harboured the genes apxI and apxII. The aqx gene was found to be specific for A. equuli subsp. haemolyticus, since A. equuli subsp. equuli contained no aqx nor any of the other RTX genes tested. The specificity of aqx for the haemolytic equine A. equuli and ApxI and ApxII for the porcine A. suis indicates a role of these RTX toxins in host species predilection of the two closely related species of bacterial pathogens and allows PCR based diagnostic differentiation of the two.
Topics: Actinobacillus; Animals; Bacterial Toxins; Genes, Bacterial; Horses; Phylogeny; RNA, Ribosomal, 16S; Species Specificity; Swine
PubMed: 12791244
DOI: 10.1051/vetres:2003010 -
Veterinary Sciences Oct 2023The diagnostic workup of respiratory disease in pigs is complex due to coinfections and non-infectious causes. The detection of pathogens associated with respiratory...
The diagnostic workup of respiratory disease in pigs is complex due to coinfections and non-infectious causes. The detection of pathogens associated with respiratory disease is a pivotal part of the diagnostic workup for respiratory disease. We aimed to report how frequently certain viruses and bacteria were detected in samples from pigs with respiratory symptoms in the course of routine diagnostic procedures. Altogether, 1975 routine diagnostic samples from pigs in Austrian swine stocks between 2016 and 2021 were analysed. PCR was performed to detect various pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV) (n = 921), influenza A virus (n = 479), porcine circovirus type 2 (PCV2) (n = 518), (.) (n = 713), (n = 198), () (n = 165) and (n = 180). (55.1%) had the highest detection rate, followed by PCV2 (38.0%) and (.) (30.6%). PRRSV was detected most frequently in a pool of lung, tonsil and tracheobronchial lymph node (36.2%). was isolated more frequently from samples taken after euthanasia compared to field samples. PRRSV-positive samples were more likely to be positive for PCV2 ( 0.001), ( = 0.032) and ( < 0.001). -positive samples were more likely to be positive for ( < 0.001) and ( 0.046), but less likely for ( = 0.004). In conclusion, our data provide evidence that lung samples that were positive for a primary pathogenic agent were more likely to be positive for a secondary pathogenic agent.
PubMed: 37888553
DOI: 10.3390/vetsci10100601 -
Veterinary Research 2001Actinobacillus suis is a commensal opportunistic pathogen in swine. However, in recent years, an increasing prevalence of clinical signs associated with A. suis has been...
Actinobacillus suis is a commensal opportunistic pathogen in swine. However, in recent years, an increasing prevalence of clinical signs associated with A. suis has been observed in high health status herds in North America. The objectives of the study were to assess the kinetics of antibodies to A. suis in pigs from a herd showing clinical signs of A. suis infection and, to evaluate the antibody response in gilts following vaccination with an autogenous vaccine. An enzyme-linked immunosorbent assay (ELISA) using a saline extract of boiled-formalinized whole cells of a field strain as the coating antigen was standardized. This ELISA was used as a tool for monitoring, in a comparative way, the variations in A. suis antibody levels. The herd selected for the serologic profile was negative for Actinobacillus pleuropneumoniae infection and showed clinical signs of A. suis infection in 16 to 19-week-old pigs. A cohort of 20 pigs was blood sampled at 5, 8, 12, and 16 weeks of age. The lowest level of serum antibodies was observed between weeks 8 and 12, this probably corresponding to a decrease in maternal immunity. A marked increase in the antibody response was seen at 16-week of age, at the approximate time of onset of A. suis clinical signs in the herd. The evaluation of serum antibody responses to an autogenous vaccine revealed that the humoral immunity of gilts further increased following vaccination although the level of antibodies was already high prior to vaccination. The magnitude of the response to vaccination was higher when the level of antibodies was low prior to the first injection. The ELISA test seems to detect antibodies against the O-chain LPS.
Topics: Actinobacillus; Actinobacillus Infections; Age Factors; Animals; Antibodies, Bacterial; Bacterial Vaccines; Cohort Studies; Enzyme-Linked Immunosorbent Assay; Sensitivity and Specificity; Serologic Tests; Swine; Swine Diseases
PubMed: 11361153
DOI: 10.1051/vetres:2001104 -
BMC Veterinary Research Apr 2009In pigs little is known about the role of innate immune defence in bacterial infections of the respiratory tract, despite their major role in pig production. In the...
BACKGROUND
In pigs little is known about the role of innate immune defence in bacterial infections of the respiratory tract, despite their major role in pig production. In the present study we characterized and compared in vitro and in vivo activation of immune markers of different pig breeds 7 days before, and 4 and 21 days after an experimental aerosol infection with Actinobacillus (A.) pleuropneumoniae.
RESULTS
In vitro stimulation of bronchoalveolar lavage fluid (BALF) and blood leukocytes with A. pleuropneumoniae, Streptococcus suis, PMA and LPS led to production of different amounts of H2O2, NO and TNF-alpha, depending on the stimulus, individual, breed and time of infection. Generally, significant responses to in vitro stimulation were observed only in blood leukocytes, whereas the alveolar macrophages showed a high basal activation. In addition, the production of haptoglobin and cytokines (TNF-alpha, IFN-gamma and IL-10) in vivo was measured in plasma and BALF. Plasma haptoglobin levels mirrored the clinical manifestations at 4 days post-infection. In plasma and BALF TNF-alpha could not be detected, whereas variable levels of IFN-gamma were found at pre- and post-infection times. IL-10 was found in some plasma but in none of the BALF samples. The different expression levels in individuals within the breeds correlated for some markers with the severity of clinical manifestations, e.g. H2O2, plasma haptoglobin and BALF IFN-gamma for German Landrace pigs.
CONCLUSION
Our findings revealed differences in the activation of the immune markers with respect to infection time, individuals and breeds. Moreover, results showed different correlation grades between the immune markers produced in vitro or in vivo and the clinical manifestations. Further analyses will have to show whether these markers may serve as correlates of protection against porcine respiratory infections.
Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Biomarkers; Breeding; Gene Expression Regulation; Linear Models; Swine; Swine Diseases; Time Factors
PubMed: 19383119
DOI: 10.1186/1746-6148-5-13 -
Frontiers in Veterinary Science 2020A comparative study on pharmacokinetics of four long-acting enrofloxacin injectable formulations was investigated in 36 healthy pigs after intramuscular injection...
A comparative study on pharmacokinetics of four long-acting enrofloxacin injectable formulations was investigated in 36 healthy pigs after intramuscular injection according to the recommended single dose @ 2.5 mg/kg body weight. The drug concentrations in the plasma were computed using high-performance liquid chromatography (HPLC) with fluorescence detection. WinNonLin5.2.1 software was used to analyze the experimental data and compared it under one-way ANOVA using SPSS software with a 95% confidence interval (CI). The main pharmacokinetic parameters, that is, the maximum plasma concentrations (C), the time to maximum concentration (T), area under the time curve concentration (AUC) and Terminal half-life (T) were 733.84 ± 129.87, 917.00 ± 240.13, 694.84 ± 163.49, 621.98 ± 227.25 ng/ml, 2.19 ± 0.0.66, 1.50 ± 0.37, 2.89 ± 0.24, 0.34 ± 0.13 h, 7754.43 ± 2887.16, 8084.11 ± 1543.98, 7369.42 ± 2334.99, 4194.10 ± 1186.62 ng h/ml, 10.48 ± 2.72, 10.37 ± 2.38, 10.20 ± 2.81, and 10.61 ± 0.86 h for 10% enrofloxacin (Alkali), 20% enrofloxacin (Acidic), Yangkang and control drug Nuokang® respectively. There were significant differences among C, T, and AUC of three formulations compare with that of the reference formulation. No significant differences were observed among the T for tested formulations compare with the reference formulation. The pharmacokinetic parameters showed that the tested formulations were somewhat better compared to the reference one. The calculated PK/PD indices were effective for bacteria such as and with values higher than the cut-off points (C/MIC≥10-12 and AUC/MIC ≥ 125). However, they were not effective against bacteria like , and where lower values were obtained.
PubMed: 33575278
DOI: 10.3389/fvets.2020.604628 -
The Journal of Veterinary Medical... Feb 2019Five-day-old neonatal piglets presented with debilitation and ananastasia. At the necropsy of one piglet, the apex of the tongue was found to be discolored dark red, and...
Five-day-old neonatal piglets presented with debilitation and ananastasia. At the necropsy of one piglet, the apex of the tongue was found to be discolored dark red, and disseminated white foci were found on the cut surface. Many white foci were also found in the lungs and on the serosa of the liver and spleen. Histopathological findings revealed multifocal necrotic glossitis and pneumonia with Gram-negative bacilli. The bacilli were identified as Actinobacillus suis through immunohistochemical, biochemical, and genetic tests, including 16S rRNA gene sequencing. Although A. suis usually causes inflammation in thoracic and abdominal organs, lesions were also found in the tongue in the present case. This study is the first report of glossitis caused by A. suis.
Topics: Actinobacillus Infections; Actinobacillus suis; Animals; Animals, Newborn; Glossitis; Necrosis; RNA, Ribosomal, 16S; Sepsis; Sequence Analysis, RNA; Tongue
PubMed: 30606907
DOI: 10.1292/jvms.18-0630 -
Frontiers in Genetics 2022The United Kingdom and European Union have banned crates for pregnant sows. However, animals are kept in a restrictive environment for up to four weeks after mating,...
The United Kingdom and European Union have banned crates for pregnant sows. However, animals are kept in a restrictive environment for up to four weeks after mating, leading to stress and different responses of the animals' immune system. Here, we used vaginal flushing of gilts to investigate whether housing systems or an experimental inflammatory challenge with lipopolysaccharide (LPS) can modify the gilt vaginal microbiome. Alpha-diversity indices showed differences in the microbiota of gilts housed under different systems ( = 0.04). Shannon alpha-diversity richness was higher in gilts group-housed in pens than in gilts housed in crates ( = 0.035), but not higher than in other groups. The relative abundance of the operational taxonomic unit (OTU) ( < 0.05) revealed specific differences in housing systems before a LPS or saline (SAL control) challenge. We found different abundances in taxa of , , , , and in gilts housed in the different systems before challenge. After the LPS challenge, significant differences were detected in the relative abundance of OTUs ( < 0.05) for the LPS-challenged group compared with SAL animals for each housing system. The phylum showed higher abundance among the LPS-challenged gilts than in SAL-challenged animals. Furthermore, was more abundant in the LPS-challenged gilts housed in crates than in SAL-challenged gilts housed in crates. and were more abundant in LPS-challenged gilts in indoor group housing than in SAL gilts in the same housing system. Gilts kept outdoors did not show changes in vaginal microbiota after an LPS challenge. Gilts housed in crates showed clinical signs of urogenital infection, whereas gilts housed outdoors and in indoor group housing did not. The relationship between environment, immune response, and microbiota suggested that animals in a poor environments experience difficulties responding to a challenge and their vaginal microbiota is altered as a consequence, with decreased richness of normal vaginal microbiota, and increased opportunistic bacteria. Welfare indicators measured by gilts' responses to housing systems however, do not fully explain mechanisms associated with the unique signature in vaginal microbiota encountered in the different housing systems.
PubMed: 35464863
DOI: 10.3389/fgene.2022.836962 -
Veterinary Sciences Feb 2024One of the main challenges for the sustainability and productivity of the Spanish swine industry is health instability, resulting in significant economic losses....
One of the main challenges for the sustainability and productivity of the Spanish swine industry is health instability, resulting in significant economic losses. Information on the main swine diseases which affect the Spanish pig industry could help in optimizing the efforts within control programs. This study determined the frequency of occurrence of the main diseases in Spain and the main control tool used, based on perceptions from veterinarians and consultants in a specific survey. Results showed that () , and coccidia are the most frequent pathogens in the gestation and lactation phase, whereas the most important were Porcine Reproductive and Respiratory Syndrome virus (PRRSV). In the nursery phase, the most frequent were , and PRRSV, the latter being the most important for the participants. Finally, in the fattening phase, PRRSV and were the most frequent and important pathogen, respectively. Statistical differences among responses were detected with respect to the location and the gestation and lactation phases by farm size. Regarding the tools used for controlling the diseases, vaccination was the main strategy in all production phases, except in the fattening period, in which antibiotherapy was the most common response from the participants. Finally, the improvement of management practices was the most proposed tool, suggesting its importance within control programs.
PubMed: 38393102
DOI: 10.3390/vetsci11020084 -
The Canadian Veterinary Journal = La... Oct 2015
Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Canada; Serogroup; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases
PubMed: 26483588
DOI: No ID Found