-
PloS One 2019Actinobacillus pleuropneumoniae, Pasteurella multocida and Streptococcus suis are prevalent bacterial causes of swine infections. Morbidity, mortality and positively...
Mutant prevention and minimum inhibitory concentration drug values for enrofloxacin, ceftiofur, florfenicol, tilmicosin and tulathromycin tested against swine pathogens Actinobacillus pleuropneumoniae, Pasteurella multocida and Streptococcus suis.
Actinobacillus pleuropneumoniae, Pasteurella multocida and Streptococcus suis are prevalent bacterial causes of swine infections. Morbidity, mortality and positively impacting the financial burden of infection occurs with appropriate antimicrobial therapy. Increasing antimicrobial resistance complicates drug therapy and resistance prevention is now a necessity to optimize therapy and prolong drug life. Mutant bacterial cells are said to arise spontaneously in bacterial densities of 107-109 or greater colony forming units/ml. Antibiotic drug concentration inhibiting growth of the least susceptible cell in these high density populations has been termed the mutant prevention concentration (MPC). In this study MPC and minimum inhibitory concentration (MIC) values of ceftiofur, enrofloxacin, florfenicol, tilmicosin and tulathromycin were determined against the swine pathogens A. pleuropneumoniae, P.multocida and S. suis. The following MIC90/MPC90 values (mg/L) for 67 A. pleuropneumoniae and 73 P. multocida strains respectively were as follows: A. pleuropneumoniae 0.031/0.5, ≤0.016/0.5, 0.5/2, 4/32, 2/32; P. multocida 0.004/0.25, 0.016/0.125, 0.5/0.5, 8/16, 0.5/1. For 33 S. suis strains, MIC90 values (mg/L) respectively were as follows: 1, 0.25, 4, ≥8 and ≥8. A total of 16 S. suis strains with MIC values of 0.063-0.5 mg/L to ceftiofur and 0.25-0.5 mg/L to enrofloxacin were tested by MPC; MPC values respectively were 0.5 and 1 mg/L respectively. MPC concentrations provide a dosing target which may serve to reduce amplification of bacterial subpopulations with reduced antimicrobial susceptibility. Drug potency based on MIC90 values was ceftiofur > enrofloxacin >florfenicol = tulathromycin > tilmicosin; based on MPC90 values was enrofloxacin > ceftiofur > tulathromycin > florfenicol ≥ tilmicosin.
Topics: Actinobacillus pleuropneumoniae; Animal Husbandry; Animals; Anti-Bacterial Agents; Cephalosporins; Disaccharides; Drug Resistance, Multiple, Bacterial; Enrofloxacin; Heterocyclic Compounds; Microbial Sensitivity Tests; Pasteurella multocida; Streptococcus suis; Swine; Swine Diseases; Thiamphenicol; Tylosin
PubMed: 30629633
DOI: 10.1371/journal.pone.0210154 -
Animals : An Open Access Journal From... Apr 2023Porcine Respiratory Diseases Complex (PRDC) is a multifactorial disease that involves several bacterial pathogens, including , , , , and In pigs, the infection may...
Porcine Respiratory Diseases Complex (PRDC) is a multifactorial disease that involves several bacterial pathogens, including , , , , and In pigs, the infection may cause lesions such pleurisy, which can lead to carcass condemnation. Hence, 1015 carcasses were selected from three different commercial pig farms, where the respiratory conditions were evaluated using slaughterhouse pleurisy evaluation system (SPES) and classified into five groups. In total, 106 pleural and lung fragments were collected for qPCR testing to identify the five abovementioned pathogens. A moderate correlation between the severity of the lesions and the presence of (R = 0.38) and (R = 0.28) was observed. Concerning the lung samples, the severity of the lesions was moderately correlated with the presence of (R = 0.43) and (R = 0.35). Moreover, there was a strong correlation between the presence of and in the pleura (R = 0.82). Finally, this approach may be a useful tool to identify and quantify causative agents of PRDC using qPCR, providing a comprehensive evaluation of its relevance, strength, and potential application in the field as a surveillance tool for veterinarians.
PubMed: 37174529
DOI: 10.3390/ani13091493 -
Canadian Journal of Veterinary Research... Apr 2008Tonsillar and nasal swabs were collected from weanling pigs in 50 representative Ontario swine herds and tested for the presence of 5 important bacterial upper...
Prevalence of Actinobacillus pleuropneumoniae, Actinobacillus suis, Haemophilus parasuis, Pasteurella multocida, and Streptococcus suis in representative Ontario swine herds.
Tonsillar and nasal swabs were collected from weanling pigs in 50 representative Ontario swine herds and tested for the presence of 5 important bacterial upper respiratory tract pathogens. All but 1 herd (2%) tested positive for Streptococcus suis by polymerase chain reaction (PCR); 48% of herds were S. suis serovar 2, 1/2 positive. In all but 2 herds there was evidence of Haemophilus parasuis infection. In contrast, toxigenic strains of Pasteurella multocida were detected by a P. multocida--enzyme-linked immunosorbant assay (PMT-ELISA) in only one herd. Seventy-eight percent of the herds were diagnosed positive for Actinobacillus pleuropneumoniae by apxIV PCR. Sera from finishing pigs on the same farms were also collected and tested by ELISA for the presence of A. pleuropneumoniae antibodies. Seventy percent of the herds tested had evidence of antibodies to A. pleuropneumoniae including serovars 1-9-11 (2%), 2 (4%), 3-6-8-15 (15%), 5 (6%), 4-7 (26%), and 12 (17%). This likely represents a shift from previous years when infection with A. pleuropneumoniae serovars 1, 5, and 7 predominated. At least 16% and possibly as many as 94% of the herds tested were Actinobacillus suis positive; only 3 of the 50 herds were both A. pleuropneumoniae and A. suis negative as judged by the absence of a positive PCR test for apxII. Taken together, these data suggest that over the past 10 years, there has been a shift in the presence of pathogenic bacteria carried by healthy Ontario swine with the virtual elimination of toxigenic strains of P. multocida and a move to less virulent A. pleuropneumoniae serovars. As well, there appears to be an increase in prevalence of S. suis serovar 2, 1/2, but this may be a reflection of the use of a more sensitive detection method.
Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Actinobacillus suis; Animals; Antibodies, Bacterial; Enzyme-Linked Immunosorbent Assay; Female; Haemophilus Infections; Haemophilus paragallinarum; Male; Nasal Cavity; Ontario; Palatine Tonsil; Pasteurella Infections; Pasteurella multocida; Polymerase Chain Reaction; Prevalence; Sensitivity and Specificity; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases
PubMed: 18505187
DOI: No ID Found -
International Journal of Molecular... Aug 2022(, Gram negative) and (.) (Gram positive) can cause severe diseases in pigs. During infection, neutrophils infiltrate to counteract these pathogens with phagocytosis...
(, Gram negative) and (.) (Gram positive) can cause severe diseases in pigs. During infection, neutrophils infiltrate to counteract these pathogens with phagocytosis and/or neutrophil extracellular traps (NETs). NETs consist of a DNA-backbone spiked with antimicrobial components. The NET formation mechanisms in porcine neutrophils as a response to both of the pathogens are not entirely clear. The aim of this study was to investigate whether (serotype 2, C3656/0271/11) and (serotype 2, strain 10) induce NETs by NADPH oxidase- or CD18-dependent mechanisms and to characterize phenotypes of NETs in porcine neutrophils. Therefore, we investigated NET induction in porcine neutrophils in the presence and absence of NET inhibitors and quantified NETs after 3 h. Furthermore, NETosis and phagocytosis were investigated by transmission electron microscopy after 30 min to characterize different phenotypes. and induce NETs that are mainly ROS-dependent. induces NETs that are partially CD18-dependent. Thirty minutes after infection, both of the pathogens induced a vesicular NET formation with only slight differences. Interestingly, some neutrophils showed only NET-marker positive phagolysosomes, but no NET-marker positive vesicles. Other neutrophils showed vesicular NETs and only NET-marker negative phagolysosomes. In conclusion, both of the pathogens induce ROS-dependent NETs. Vesicular NETosis and phagocytosis occur in parallel in porcine neutrophils in response to serotype 2 and serotype 2.
Topics: Animals; Bacterial Infections; Extracellular Traps; Neutrophils; Reactive Oxygen Species; Streptococcus suis; Swine
PubMed: 36012224
DOI: 10.3390/ijms23168953 -
Genomics Jan 2019Actinobacillus spp. are Gram-negative bacteria associated with mucosal membranes. While some are commensals, others can cause important human and animal diseases. A....
Actinobacillus spp. are Gram-negative bacteria associated with mucosal membranes. While some are commensals, others can cause important human and animal diseases. A. pleuropneumoniae causes severe fibrinous hemorrhagic pneumonia in swine but not systemic disease whereas other species invade resulting in septicemia and death. To understand the invasive phenotype of Actinobacillus spp., complete genomes of eight isolates were obtained and pseudogenomes of five isolates were assembled and annotated. Phylogenetically, A. suis isolates clustered by surface antigen type and were more closely related to the invasive A. ureae, A. equuli equuli, and A. capsulatus than to the other swine pathogen, A. pleuropneumoniae. Using the LS-BSR pipeline, 251 putative virulence genes associated with serum resistance and invasion were detected. To our knowledge, this is the first genome-wide study of the genus Actinobacillus and should contribute to a better understanding of host tropism and mechanisms of invasion of pathogenic Actinobacillus and related genera.
Topics: Actinobacillus; Animals; Gene Rearrangement; Genetic Variation; Genome-Wide Association Study; Genomics; Host Specificity; N-Acetylneuraminic Acid; Neuraminidase; Phenotype; Phylogeny; Pseudogenes; Sequence Inversion; Serine Endopeptidases; Swine; Type V Secretion Systems; Virulence; Whole Genome Sequencing
PubMed: 29317305
DOI: 10.1016/j.ygeno.2018.01.001 -
Infection and Immunity Oct 2016Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and...
Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and invasion of bacterial pathogens. Actinobacillus suis is a common resident of the tonsils of the soft palate in pigs, but under certain circumstances it can invade, causing septicemia and related sequelae. Twenty-four putative adhesins are predicted in the A. suis genome, but to date, little is known about how they might participate in colonization or invasion. To better understand these processes, swine tonsil lysates were characterized by mass spectrometry. Fifty-nine extracellular matrix (ECM) proteins were identified, including small leucine-rich proteoglycans, integrins, and other cell surface receptors. Additionally, attachment of the wild type and 3 adhesin mutants to 5 ECM components was evaluated. Exponential cultures of wild-type A. suis adhered significantly more than stationary cultures to all ECM components studied except collagen I. During exponential growth, the A. suis Δflp1 mutant attached less to collagen IV while the ΔompA mutant attached less to all ECMs. The ΔcomE1 strain attached less to collagen IV, fibronectin, and vitronectin during exponential growth and exhibited differential attachment to collagen I over short adherence time points. These results suggest that Flp1, OmpA, and ComE1 are important during early stages of attachment to ECM components found in tonsils, which supports the notion that other adhesins have compensatory effects during later stages of attachment.
Topics: Actinobacillus suis; Adhesins, Bacterial; Animals; Bacterial Adhesion; Extracellular Matrix; Extracellular Matrix Proteins; Mass Spectrometry; Palate, Soft; Palatine Tonsil; Swine
PubMed: 27481253
DOI: 10.1128/IAI.00456-16 -
The Canadian Veterinary Journal = La... Dec 2020Medical records of 20 horses with a confirmed diagnosis of valvular endocarditis at the Ontario Veterinary College between January 1, 1993 and February 3, 2020 were...
Medical records of 20 horses with a confirmed diagnosis of valvular endocarditis at the Ontario Veterinary College between January 1, 1993 and February 3, 2020 were reviewed. The diagnosis was based on physical examination findings, complete blood (cell) count (CBC), serum biochemistry, echocardiography, blood culture, and post-mortem findings. Common presenting signs included tachycardia, pyrexia, weight loss, lameness/joint distension, and a heart murmur. Clinicopathological findings included leukocytosis, anemia, hypoalbuminemia, hyperglobulinemia, and elevated inflammatory markers. Culture from 5 horses yielded in 2 cases and in 1 case. Of the 20 horses included in this study, 17 were euthanized and 3 were treated. Only 1 case had follow-up more than 1 year after discharge.
Topics: Animals; Echocardiography; Endocarditis; Euthanasia, Animal; Horse Diseases; Horses; Ontario
PubMed: 33299245
DOI: No ID Found -
Veterinary Record Open Dec 2022The Gram-negative bacterium is an agent of global importance to the swine industry and the cause of lethal respiratory or septicaemic disease in pigs of different ages....
OBJECTIVE
The Gram-negative bacterium is an agent of global importance to the swine industry and the cause of lethal respiratory or septicaemic disease in pigs of different ages. Between 2018 and 2019, seven commercial farms in western Canada experienced episodes of increased mortality due to infection in grower pigs. The goal of this work was to profile, with molecular methods, isolated from diseased pigs and to compare them to other isolates.
DESIGN
This inferential observational study used nine western Canadian strains obtained from diseased lungs ( = 6), heart ( = 2) and brain ( = 1) and whole genome sequencing was performed. Comparative genomic analyses were performed to characterise the genetic variability, antimicrobial resistance and the virulence genes present.
RESULTS
Compared to the reference strain (ATCC 33415), an increased number of RTX (repeats in the structural toxin) gene copies were identified in strains isolated from organs without a mucosal surface, thus theoretically harder to invade. Western Canadian strains did not harbour genes associated with resistance to antimicrobial agents used in swine production. Novel regions were also identified in the genomes of five of nine strains demonstrating recombination and emergence of novel strains.
CONCLUSIONS
The results obtained in this study were associated with the emergence of new lineages. An increased number of RTX toxin gene copies is suggested to be associated with increased virulence. This study will contribute to improve our understanding regarding and may help guide vaccine development and agent control measures.
PubMed: 36213600
DOI: 10.1002/vro2.45 -
Journal of Clinical Microbiology May 1997Actinobacillus suis isolates recovered from both healthy and diseased pigs were characterized by biochemical testing, serotyping, restriction endonuclease...
Actinobacillus suis isolates recovered from both healthy and diseased pigs were characterized by biochemical testing, serotyping, restriction endonuclease fingerprinting, and apx toxin gene typing. The clinical isolates analyzed were collected over a 10-year period from approximately 40 different locations in southwestern Ontario, Canada. Little variation in the biochemical profiles of these isolates was seen, and all isolates reacted strongly with rabbit antisera prepared against one of the strains. Similarly, by using BamHI and BglII for restriction endonuclease fingerprinting (REF) analysis, all isolates were found to belong to a single REF group. Minor variations could be detected, especially in the BglII fingerprints, but overall the patterns were remarkably similar. Sequences that could be amplified by PCR with primers to the apxICA and apxIICA genes of Actinobacillus pleuropneumoniae were detected in all strains. Although no amplification was obtained with primers to the A. pleuropneumoniae apxIBD genes, sequences with homology to apxIBD were detected by hybridization. There was no evidence of apxIII homologs. Taken together, these data suggest that A. suis isolates are genotypically and phenotypically very similar, regardless of their source, and that they contain genes similar to, but not identical to, the apxICABD and apxIICA genes of A. pleuropneumoniae.
Topics: Actinobacillus; Actinobacillus Infections; Animals; Bacterial Proteins; Bacterial Toxins; Genes, Bacterial; Hemolysin Proteins; Rabbits; Swine; Swine Diseases
PubMed: 9114394
DOI: 10.1128/jcm.35.5.1131-1137.1997 -
Infection and Immunity Sep 1994The three Apx toxins of Actinobacillus pleuropneumoniae have potential value for use in vaccines and diagnostic tests which will be species specific instead of serotype...
The three Apx toxins of Actinobacillus pleuropneumoniae have potential value for use in vaccines and diagnostic tests which will be species specific instead of serotype specific, provided that the Apx toxins are species specific and all field strains produce these toxins. We examined 114 A. pleuropneumoniae field strains and found that they secreted either ApxI, ApxII, ApxI and ApxII, or ApxII and ApxIII and secreted no other cytolytic activities. However, proteins similar to ApxI and ApxII were also produced by Actinobacillus suis.
Topics: Actinobacillus; Actinobacillus pleuropneumoniae; Bacterial Proteins; Bacterial Toxins; Enzyme-Linked Immunosorbent Assay; Hemolysin Proteins
PubMed: 8063425
DOI: 10.1128/iai.62.9.4063-4065.1994