phenylephrine-hydrochloride and Actinobacillus-Infections

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Bacterial Proteins; Bacterial Toxins; Bacterial Typing Techniques; DNA, Bacterial; Lung; Nose; Polymerase Chain Reaction; Serotyping; Swine; Swine Diseases

A real-time quantitative PCR (qPCR) for detection of the apxIVA gene of Actinobacillus pleuropneumoniae was validated using pure cultures of A. pleuropneumoniae and tonsillar and nasal swabs from experimentally inoculated Caesarean-derived/colostrum-deprived piglets and naturally infected conventional pigs. The analytical sensitivity was 5colony forming units/reaction. In comparison with selective bacterial examination using tonsillar samples from inoculated animals, the diagnostic sensitivity of the qPCR was 0.98 and the diagnostic specificity was 1.0. The qPCR showed consistent results in repeatedly sampled conventional pigs. Tonsillar brush samples and apxIVA qPCR analysis may be useful for further epidemiological studies and monitoring for A. pleuropneumoniae.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Bacterial Proteins; Cesarean Section; Colostrum; Nose; Palatine Tonsil; Real-Time Polymerase Chain Reaction; Sensitivity and Specificity; Sequence Analysis, DNA; Swine; Swine Diseases

The purpose of the study was to evaluate the clinical significance of Actinobacillus minor, Actinobacillus porcinus and Actinobacillus indolicus strains in gnotobiotic piglets. Twenty-two 6-h-old Caesarean-delivered and colostrum-deprived piglets were intranasally and orally inoculated with 2 x 10(6) colony-forming units of an A. minor (group 2; n = 9), A. indolicus (group 3; n = 5), or A. porcinus (group 4; n = 8) strain. Six other piglets were inoculated in the same way with phosphate-buffered saline solution and used as controls (group 1). All pigs were observed for clinical signs and rectal temperatures were taken until euthanasia 7 days after inoculation. At necropsy, conchae, tonsils, lungs, brains, liver, spleen and kidneys were macroscopically examined for lesions and samples were taken for bacteriology. None of the pigs developed fever. Mild ataxia was observed in one pig from group 3 for 2 days. Clinical signs were not observed in the other animals. In none of the animals were macroscopic lesions detected at necropsy. NAD-dependent Pasteurellaceae were not isolated from control animals (group 1). The A. minor, A. indolicus and A. porcinus strains were isolated from the tonsils of one, two and one pigs, respectively. Actinobacillus porcinus was isolated from the brains of the pig with central nervous symptoms and from the conchae of another pig. The inoculation strains were not demonstrated in the other samples. It was concluded that, using these inoculation routes and dose, the A. minor, A. indolicus and A. porcinus strains had low capacity to colonize the upper respiratory tract of gnotobiotic piglets and demonstrated low or no pathogenicity in such animals.

Topics: Actinobacillus; Actinobacillus Infections; Animals; Animals, Newborn; Germ-Free Life; Nose; Palatine Tonsil; Swine; Swine Diseases

A PCR assay for the detection of Actinobacillus pleuropneumoniae was developed based on the amplification of a dsbE-like gene. All of 157 field isolates of A. pleuropneumoniae reacted in the PCR by the amplification of a 342bp product. No reaction was observed with related bacterial species or other bacterial species isolated from pigs, except for A. lignieresii. The lower detection limit of the PCR was 10(2) CFU per PCR test tube and was not affected by the addition of 10(6) CFU Escherichia coli. The PCR was evaluated on mixed bacterial cultures from nasal and tonsillar swabs as well as suspensions of nasal conchae and tonsils obtained from specific pathogen-free (SPF) pigs, experimentally infected pigs, and pigs from farrow-to-finish herds. The results of the new PCR were compared with a PCR based on the detection of the omlA gene coding for an outer membrane protein, with a commercially available PCR (Adiavet APP, Adiagène, Saint-Brieuc, France), and with conventional culturing. No positive reactions were observed with any of the PCR methods in samples of SPF animals. In samples of the other animals, no or low significant differences between nasal swabs and suspensions as well as tonsillar swabs and suspensions were observed in any method. In general, more positive results were obtained from tonsillar samples in comparison to nasal samples. Interassay sensitivity and specificity values were assessed for each test by pair wise comparisons between assays. The agreement between tests was evaluated by calculating Cohen's kappa coefficient. From these analyses the three PCR assays showed a good agreement. The dsbE-based PCR proved to be highly sensitive (95 and 93%) and specific (82 and 74%) in comparison to the omlA-based PCR and the commercially available PCR, respectively. It was concluded that the dsbE-like gene-based PCR is a reliable diagnostic assay for demonstration of A. pleuropneumoniae. Furthermore, it was demonstrated that tonsillar swabs can be used for the detection of the pathogen in healthy carrier animals.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Amino Acid Sequence; Animals; Base Sequence; Colony Count, Microbial; Consensus Sequence; DNA, Bacterial; Gene Amplification; Molecular Sequence Data; Nose; Palatine Tonsil; Polymerase Chain Reaction; Sensitivity and Specificity; Specific Pathogen-Free Organisms; Swine; Swine Diseases

Serotyping of Actinobacillus pleuropneumoniae is based on detection of the serotype-specific capsular antigen. However, not all isolates can be serotyped, and some may cross-react with multiple serotyping reagents. To improve sensitivity and specificity of serotyping and for early detection, a multiplex PCR assay was developed for detection of A. pleuropneumoniae and identification of serotype 5 isolates. DNA sequences specific to the conserved export and serotype-specific biosynthesis regions of the capsular polysaccharide of A. pleuropneumoniae serotype 5 were used as primers to amplify 0.7- and 1.1-kb DNA fragments, respectively. The 0.7-kb fragment was amplified from all strains of A. pleuropneumoniae tested with the exception of serotype 4. The 0.7-kb fragment was not amplified from any heterologous species that are also common pathogens or commensals of swine. In contrast, the 1.1-kb fragment was amplified from all serotype 5 strains only. The assay was capable of amplifying DNA from less than 10(2) CFU. The A. pleuropneumoniae serotype 5 capsular DNA products were readily amplified from lung tissues obtained from infected swine, although the 1.1-kb product was not amplified from some tissues stored frozen for 6 years. The multiplex PCR assay enabled us to detect A. pleuropneumoniae rapidly and to distinguish serotype 5 strains from other serotypes. The use of primers specific to the biosynthesis regions of other A. pleuropneumoniae serotypes would expand the diagnostic and epidemiologic capabilities of this assay.

Topics: Actinobacillus Infections; Actinobacillus pleuropneumoniae; Animals; Bacterial Capsules; Bacterial Typing Techniques; Blotting, Southern; DNA Primers; DNA, Bacterial; Electrophoresis, Agar Gel; Lung; Nose; Pleuropneumonia; Polymerase Chain Reaction; Sensitivity and Specificity; Serotyping; Species Specificity; Swine; Swine Diseases

The literature on granulomatous nasal diseases of cattle is reviewed, with emphasis on nasal granuloma, a disease of unknown cause which is enzootic in Australian dairy cattle. It is concluded that on available evidence the disease is most probably a form of allergic rhinitis.

Topics: Actinobacillus Infections; Animals; Cattle; Cattle Diseases; Female; Granuloma; Male; Mycetoma; Nose; Nose Diseases; Schistosomiasis