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BMC Microbiology Jun 2016Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, which causes important worldwide economic losses in the swine industry....
BACKGROUND
Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, which causes important worldwide economic losses in the swine industry. Several respiratory tract infections are associated with biofilm formation, and A. pleuropneumoniae has the ability to form biofilms in vitro. Biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that are attached to an abiotic or biotic surface. Virtually all bacteria can grow as a biofilm, and multi-species biofilms are the most common form of microbial growth in nature. The goal of this study was to determine the ability of A. pleuropneumoniae to form multi-species biofilms with other bacteria frequently founded in pig farms, in the absence of pyridine compounds (nicotinamide mononucleotide [NMN], nicotinamide riboside [NR] or nicotinamide adenine dinucleotide [NAD]) that are essential for the growth of A. pleuropneumoniae.
RESULTS
For the biofilm assay, strain 719, a field isolate of A. pleuropneumoniae serovar 1, was mixed with swine isolates of Streptococcus suis, Bordetella bronchiseptica, Pasteurella multocida, Staphylococcus aureus or Escherichia coli, and deposited in 96-well microtiter plates. Based on the CFU results, A. pleuropneumoniae was able to grow with every species tested in the absence of pyridine compounds in the culture media. Interestingly, A. pleuropneumoniae was also able to form strong biofilms when mixed with S. suis, B. bronchiseptica or S. aureus. In the presence of E. coli, A. pleuropneumoniae only formed a weak biofilm. The live and dead populations, and the matrix composition of multi-species biofilms were also characterized using fluorescent markers and enzyme treatments. The results indicated that poly-N-acetyl-glucosamine remains the primary component responsible for the biofilm structure.
CONCLUSIONS
In conclusion, A. pleuropneumoniae apparently is able to satisfy the requirement of pyridine compounds through of other swine pathogens by cross-feeding, which enables A. pleuropneumoniae to grow and form multi-species biofilms.
Topics: Acetylglucosamine; Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Biofilms; Bordetella bronchiseptica; Culture Media; Deoxyribonuclease I; Endopeptidase K; Escherichia coli; In Situ Hybridization, Fluorescence; Microscopy, Confocal; NAD; Niacinamide; Nicotinamide Mononucleotide; Pasteurella multocida; Pyridines; Pyridinium Compounds; Species Specificity; Staphylococcus aureus; Stem Cells; Streptococcus suis; Swine; Swine Diseases
PubMed: 27349384
DOI: 10.1186/s12866-016-0742-3 -
Veterinary Microbiology Oct 2016VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme that collects pathogens from diseased cattle, pigs and poultry. In the current study,...
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 from cattle and P. multocida, Actinobacillus pleuropneumoniae, Haemophilus parasuis, Bordetella bronchiseptica and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MIC values of 16 or 17 antibiotics were assessed centrally by broth microdilution following CLSI standards. Results were interpreted using CLSI breakpoints where available. Cattle isolates were generally highly susceptible to most antibiotics, except to tetracycline (3.0-12.0% resistance). Low levels of resistance (0-4.0%) were observed for the macrolide antibiotics. Resistance to spectinomycin varied from 0 to 6.0%. In pig isolates similar observations were made. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tulathromycin, tiamulin and tilmicosin was absent or <2%. Trimethoprim/sulfamethoxazole resistance varied from 1.9 to 5.3%, but tetracycline resistance varied from 20.4% in P. multocida to 88.1% in S. suis. For most antibiotics and pathogens the percentage resistance remained unchanged or only increased numerically as compared to that of the period 2002-2006. In conclusion, absence or low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from livestock. Comparison of all antibiotics and organisms was hampered since for almost half of the antibiotics no CLSI-defined breakpoints were available.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Cattle; Cattle Diseases; Drug Resistance, Bacterial; Europe; Microbial Sensitivity Tests; Respiratory System; Respiratory Tract Infections; Swine; Swine Diseases
PubMed: 27102206
DOI: 10.1016/j.vetmic.2016.04.009 -
Colloids and Surfaces. B, Biointerfaces May 2016In order to effectively control the bacterial pneumonia in pigs, doxycycline hydrochloride (DoxHcl) and florfenicol (FF) microparticle suspension together with inclusion...
Preparation, characterization and pharmacokinetics of doxycycline hydrochloride and florfenicol polyvinylpyrroliddone microparticle entrapped with hydroxypropyl-β-cyclodextrin inclusion complexes suspension.
In order to effectively control the bacterial pneumonia in pigs, doxycycline hydrochloride (DoxHcl) and florfenicol (FF) microparticle suspension together with inclusion complexes was prepared by using hydroxypropyl-β-cyclodextrin (HP-β-CD) as host molecules, polyvinylpyrroliddone (PVP) as polymer carriers and hydroxypropyl methyl cellulose (HPMC) as suspending agents. In vitro antibacterial activity, properties, stability and pharmacokinetics of the suspension were studied. The results demonstrated that DoxHcl and FF had a synergistic or additive antibacterial activity against Streptococcus suis, Actinobacillus pleuropneumoniae and Haemophilus parasuis. The size, polydispersity index and zeta potential of microparticles were 1.46 ± 0.06 μm, 0.30 ± 0.02 and 1.53 ± 0.04 mV, respectively. The encapsulation efficiency (EE) of DoxHcl and FF was 45.28% ± 3.30% and 89.69% ± 2.71%, respectively. The re-dispersed time and sedimentation rate of the suspension were 1 min and 1. The suspension went through the 9-gage needle smoothly with withdrawal volume of 9.12 ± 0.87 mL/min. The suspension showed good stability when stored away from light, no irritation at the injection site and sustained release in PBS buffer. After intramuscular administration to pig, DoxHcl and FF could maintain over 0.15 μg/mL for 72 h. Compared to the control injection, the suspension increased the elimination half-life (T½ke) as well as mean residence time (MRT) of DoxHcl from 5.73 to 9.77 h and from 12.02 to 18.81 h, and those of FF from 12.02 to 26.19 h and from 12.02 to 28.16 h, respectively. The suspension increased the bioavailability of DoxHcl and FF by 1.74 and 1.13-fold, respectively. These results suggest that the compound suspension is a promising formulation for pig pneumonia therapy.
Topics: 2-Hydroxypropyl-beta-cyclodextrin; Actinobacillus pleuropneumoniae; Animals; Anti-Bacterial Agents; Area Under Curve; Doxycycline; Drug Compounding; Drug Liberation; Female; Haemophilus parasuis; Male; Metabolic Clearance Rate; Microbial Sensitivity Tests; Microscopy, Electron, Scanning; Particle Size; Povidone; Streptococcus suis; Suspensions; Swine; Thiamphenicol; beta-Cyclodextrins
PubMed: 26918512
DOI: 10.1016/j.colsurfb.2016.02.027 -
BMC Research Notes Nov 2015Actinobacillus suis disease has been reported in a wide range of vertebrate species, but is most commonly found in swine. A. suis is a commensal of the tonsils of the...
BACKGROUND
Actinobacillus suis disease has been reported in a wide range of vertebrate species, but is most commonly found in swine. A. suis is a commensal of the tonsils of the soft palate of swine, but in the presence of unknown stimuli it can invade the bloodstream, causing septicaemia and sequelae such as meningitis, arthritis, and death. It is genotypically and phenotypically similar to A. pleuropneumoniae, the causative agent of pleuropneumonia, and to other members of the family Pasteurellaceae that colonise tonsils. At present, very little is known about the genes involved in attachment, colonisation, and invasion by A. suis (or related members of the tonsil microbiota).
RESULTS
Bioinformatic analyses of the A. suis H91-0380 genome were done using BASys and blastx in GenBank. Forty-seven putative adhesin-associated genes predicted to encode 24 putative adhesins were discovered. Among these are 6 autotransporters, 25 fimbriae-associated genes (encoding 3 adhesins), 12 outer membrane proteins, and 4 additional genes (encoding 3 adhesins). With the exception of 2 autotransporter-encoding genes (aidA and ycgV), both with described roles in virulence in other species, all of the putative adhesin-associated genes had homologues in A. pleuropneumoniae. However, the majority of the closest homologues of the A. suis adhesins are found in A. ureae and A. capsulatus--species not known to infect swine, but both of which can cause systemic infections.
CONCLUSIONS
A. suis and A. pleuropneumoniae share many of the same putative adhesins, suggesting that the different diseases, tissue tropism, and host range of these pathogens are due to subtle genetic differences, or perhaps differential expression of virulence factors during infection. However, many of the putative adhesins of A. suis share even greater homology with those of other pathogens within the family Pasteurellaceae. Similar to A. suis, these pathogens (A. capsulatus and A. ureae) cause systemic infections and it is tempting to speculate that they employ similar strategies to invade the host, but more work is needed before that assertion can be made. This work begins to examine adhesin-associated factors that allow some members of the family Pasteurellaceae to invade the bloodstream while others cause a more localised infection.
Topics: Actinobacillus suis; Adhesins, Bacterial; Computational Biology; Pasteurellaceae
PubMed: 26567540
DOI: 10.1186/s13104-015-1659-x -
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 -
Viral Immunology Oct 2015This study describes an erythema multiforme (EM) in breeding sows, after their mixing in the group housing system. Sows at 30-35 days of gestation showed red and raised...
This study describes an erythema multiforme (EM) in breeding sows, after their mixing in the group housing system. Sows at 30-35 days of gestation showed red and raised skin areas, depression, anorexia, fever, respiratory problems, and increased return to estrus. Blood and nasal samples from diseased sows were examined by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay for respiratory pathogens. Hematological and biochemical analyses were performed on the blood samples. From diseased sows, vaginal swabs for microbiological examinations and samples at slaughterhouse for gross and microscopic examinations were collected. Samples from the complete gestation and lactation feed were examined for mycotoxins. All sampled sows were seropositive for Actinobacillus pleuropneumoniae (App) and porcine reproductive and respiratory syndrome virus (PRRSV). No viremia for PRRSV and porcine circovirus type 2 were detected. All nasal samples were positive for Streptococcus suis, one for Swine Influenza Virus and one for App, Hemophilus parasuis, and S. suis. In all vaginal swabs, Escherichia coli and Streptococcus spp. were detected. Diseased sows had moderate leukocytosis, mild anemia, and thrombocytopenia. No mycotoxins were detected in feed. Histopathological examination revealed increased vascularization of the superficial and middle dermis. EM was likely due to illness caused by viral and bacterial infections. This study suggests that stress caused by the sows' mixing might have triggered the problem.
Topics: Animals; Bacteria; Erythema Multiforme; Female; Histocytochemistry; Microscopy; Porcine respiratory and reproductive syndrome virus; Respiratory Tract Diseases; Swine; Swine Diseases
PubMed: 26266696
DOI: 10.1089/vim.2015.0063 -
Vaccine Oct 2015Actinobacillus pleuropneumoniae, Actinobacillus suis, and Haemophilus parasuis are bacterial pathogens from the upper respiratory tract that are responsible for a...
Actinobacillus pleuropneumoniae, Actinobacillus suis, and Haemophilus parasuis are bacterial pathogens from the upper respiratory tract that are responsible for a substantial burden of porcine disease. Although reduction of disease has been accomplished by intensive management practices, immunization remains an important strategy for disease prevention, particularly when intensive management practices are not feasible or suitable. An attractive target for vaccine development is the surface receptor involved in acquiring iron from host transferrin, since it is common to all three pathogenic species and has been shown to be essential for survival and disease causation. It has also recently been demonstrated that an engineered antigen derived from the lipoprotein component of the receptor, transferrin-binding protein B (TbpB), was more effective at preventing infection by H. parasuis than a commercial vaccine product. This study was initiated to explore the genetic and immunogenic diversity of the transferrin receptor system from these species. Nucleic acid sequences were obtained from a geographically and temporally diverse collection of isolates, consisting of 41 A. pleuropneumoniae strains, 30 H. parasuis strains, and 2 A. suis strains. Phylogenetic analyses demonstrated that the receptor protein sequences cluster independently of species, suggesting that there is genetic exchange between these species such that receptor-based vaccines should logically target all three species. To evaluate the cross-reactive response of TbpB-derived antigens, pigs were immunized with the intact TbpB, the TbpB N-lobe and the TbpB C-lobe from A. pleuropneumoniae strain H49 and the resulting sera were tested against a representative panel of TbpBs; demonstrating that the C-lobe induces a broadly cross-reactive response. Overall our results indicate that there is a common reservoir for transferrin receptor antigenic variation amongst these pathogens. While this could present a challenge to future vaccine development, our results suggest a rationally designed TbpB-based vaccine may provide protection against all three pathogens.
Topics: Actinobacillus pleuropneumoniae; Actinobacillus suis; Animals; Antigenic Variation; Bacterial Proteins; Cross Reactions; Haemophilus parasuis; Male; Molecular Docking Simulation; Phylogeny; Receptors, Transferrin; Swine; Transferrin-Binding Protein B
PubMed: 26263196
DOI: 10.1016/j.vaccine.2015.07.097 -
Validation of reference genes for quantitative real-time PCR (qPCR) analysis of Actinobacillus suis.BMC Research Notes Mar 2015Quantitative real-time PCR is a valuable tool for evaluating bacterial gene expression. However, in order to make best use of this method, endogenous reference genes for...
BACKGROUND
Quantitative real-time PCR is a valuable tool for evaluating bacterial gene expression. However, in order to make best use of this method, endogenous reference genes for expression data normalisation must first be identified by carefully validating the stability of expression under experimental conditions. Therefore, the objective of this study was to validate eight reference genes of the opportunistic swine pathogen, Actinobacillus suis, grown in aerobic cultures with (Epinephrine) or without (Aerobic) epinephrine in the growth medium and in anoxic static cultures (Anoxic), and sampled during exponential and stationary phases.
RESULTS
Using the RefFinder tool, expression data were analysed to determine whether comprehensive stability rankings of selected reference genes varied with experimental design. When comparing Aerobic and Epinephrine cultures by growth phase, pyk and rpoB were both among the most stably expressed genes, but when analysing both growth phases together, only pyk remained in the top three rankings. When comparing Aerobic and Anoxic samples, proS ranked among the most stable genes in exponential and stationary phase data sets as well as in combined rankings. When analysing the Aerobic, Epinephrine, and Anoxic samples together, only gyrA ranked consistently among the top three most stably expressed genes during exponential and stationary growth as well as in combined rankings; the rho gene ranked as least stably expressed gene in this data set.
CONCLUSIONS
Reference gene stability should be carefully assessed with the design of the experiment in mind. In this study, even the commonly used reference gene 16S rRNA demonstrated large variability in stability depending on the conditions studied and how the data were analysed. As previously suggested, the best approach may be to use a geometric mean of multiple genes to normalise qPCR results. As researchers continue to validate reference genes for various organisms in multiple growth conditions and sampling time points, it may be possible to make informed predictions as to which genes may be most suitable to validate for a given experimental design, but in the meantime, the reference genes used to normalise qPCR data should be selected with caution.
Topics: Actinobacillus suis; Aerobiosis; Anaerobiosis; Bacterial Proteins; Culture Media; Epinephrine; Gene Expression; Gene Expression Profiling; Genes, Essential; Pyruvate Kinase; RNA Polymerase II; RNA, Ribosomal, 16S; Real-Time Polymerase Chain Reaction; Reference Standards
PubMed: 25884823
DOI: 10.1186/s13104-015-1045-8 -
Journal of Clinical Microbiology Jun 2015We report the first human case of meningitis and sepsis caused in a child by Actinobacillus suis or A. equuli, a common opportunistic pathogen of swine or horses,...
We report the first human case of meningitis and sepsis caused in a child by Actinobacillus suis or A. equuli, a common opportunistic pathogen of swine or horses, respectively. Identification was performed by matrix-assisted laser desorption ionization-time of flight mass spectrometry and real-time PCR assay. A previous visit to a farm was suspected as the source of infection.
Topics: Actinobacillus Infections; Actinobacillus equuli; Actinobacillus suis; Adolescent; Bacteremia; Humans; Male; Meningitis, Bacterial; Molecular Typing
PubMed: 25878346
DOI: 10.1128/JCM.00339-15 -
The Veterinary Record Mar 2015Erysipelas diagnosed in turkeys, sheep and pigs. Parasitic gastroenteritis reported in cattle on several farms. Unusual presentation of Actinobacillus suis causing...
Erysipelas diagnosed in turkeys, sheep and pigs. Parasitic gastroenteritis reported in cattle on several farms. Unusual presentation of Actinobacillus suis causing spinal abscesses in pigs on a breeder-finisher unit. First APHA diagnosis of oedema disease in pigs in East Anglia for many years. Infectious coryza confirmed in a hobby breeding flock. These are among matters discussed in the Animal and Plant Health Agency's (APHA's) disease surveillance report for November 2014.
Topics: Animals; Cattle; Cattle Diseases; Disease Outbreaks; Erysipelas; Poultry Diseases; Sentinel Surveillance; Sheep; Sheep Diseases; Swine; Swine Diseases; Turkeys; United Kingdom
PubMed: 25792678
DOI: 10.1136/vr.h1201