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S Rosendal

Publications and source records attributed to S Rosendal.

At least 55 records · Page 3Linked to original sources
PubMed1990

Prevalence of seroreactors to the 104-kilodalton hemolysin of Actinobacillus pleuropneumoniae in swine herds.

A rabbit homologous polyclonal antiserum to the 104-kilodalton hemolysin of Actinobacillus pleuropneumoniae serotype 1 strain CM-5 was specifically produced and used in an antigen capture enzyme-linked immunosorbent assay (ELISA) to detect swine serum antibodies to this potentially important virulence factor. Sera from pigs experimentally infected with the most common disease-producing serotypes (serotypes 1, 2, 5, and 7) of A. pleuropneumoniae produced positive results in this ELISA. Of 144 serum samples collected from 10 herds free of pleuropneumonia and 155 serum samples from 11 herds with a history of the disease, 68 (47%) and 148 (95%), respectively, were found positive by the ELISA. In addition, pigs naturally infected with Actinobacillus suis produced antibodies which seroreacted in this ELISA. The results indicated that a high proportion of swine have antibodies seroreactive with the 104-kilodalton hemolysin produced by A. pleuropneumoniae.

Actinobacillus↗
PubMed1990

A group level analysis of the associations between antibodies to seven putative pathogens and respiratory disease and weight gain in Ontario feedlot calves.

The associations, at the group level, between serological titer to Pasteurella haemolytica surface antigens (Ph), Pasteurella haemolytica cytotoxin (Ph-cytox), infectious bovine rhinotracheitis virus (IBRV), bovine virus diarrhea virus (BVDV), parainfluenza-3 virus (PIV3), respiratory syncytial virus (RSV), Mycoplasma dispar (Md), M. bovis (Mb), and respiratory disease treatment rates, relapse rates, and 28 day weight gains were investigated in 14 groups of calves entering two feedlots during years 1983-1985, in Ontario. Based on least squares regression analyses, seroconversion rates to Mb and BVDV were predictive of increased respiratory disease rates, and seroconversion rates to Ph, Ph-cytox, Md and PIV3 were predictive of decreased weight gains. The R2 for predicting weight gains was much higher than for morbidity rates (0.75 vs 0.47 respectively). Titer data were not predictive of relapse rates. Group level analyses were performed because calves are managed as groups (e.g. pens) in commercial feedlots. Only BVDV seroconversion rates were related to increased risk of respiratory disease at both the individual and group levels of organization. Mycoplasma may be important factors in causing respiratory disease, and their relationship to potentiating the effects of other respiratory pathogens needs further investigation.

Animals↗
PubMed1990

Serodiagnosis of pleuropneumonia using enzyme-linked immunosorbent assay with capsular polysaccharide antigens of Actinobacillus pleuropneumoniae serotypes 1, 2, 5 and 7.

Capsular polysaccharide antigens of serotypes 1, 2, 5 and 7 of Actinobacillus pleuropneumoniae were used in enzyme-linked immunosorbent assays (ELISAs) to test sera from experimentally infected and field pigs. Specific reactions were found in sera of experimental pigs with antigens of serotypes 1, 5 and 7 whereas the serotype 2 antigen was cross-reactive. A 1:200 serum dilution was used for testing of 300 sera from 21 swine herds in southern Ontario. Cases of pleuropneumonia had occurred in 11 of these herds, but not in the others. The negative cut-off value was the mean optical density at 405 nm (OD405) + three standard deviations (SD) for 16 negative reference sera. Sera from four pigs naturally infected with Actinobacillus suis were tested and found to react to varying degrees with each of the antigens. Therefore a second cut-off value was determined as the mean OD405 + 2 SD for the A. suis sera. Sera which, in the ELISA produced OD readings above the latter cut-off were considered positive for antibodies to A. pleuropneumoniae; those which were lower than the former cut-off were considered negative. Readings between the two cut-off values may have been due to low positive titers or cross-reactivity, possibly with A. suis, and could not be used to predict pleuropneumonia. Of the pleuropneumonia-free herds, none had positive reactors to serotypes 5 or 7, whereas one and two herds had positive reactors to serotypes 1 and 2, respectively. Of the pleuropneumonia positive herds, six had positive reactors to serotype 1, one to serotype 2, four to serotype 5, and eight to serotype 7.

Actinobacillus↗
PubMed1990

Characterization of an attenuated strain of Actinobacillus pleuropneumoniae, serotype 1.

Pleuropneumonia is an important disease of swine caused by Actinobacillus pleuropneumoniae. Putative virulence determinants include capsule, lipopolysaccharide, and cytotoxin. We studied the virulence and virulence determinants of 2 strains: CM5 and CM5A of serotype 1. Strain CM5 was isolated from a pig with pleuropneumonia and passaged once in vitro; strain CM5A was a substrain of CM5 passaged 70 times in vitro. Pigs challenge exposed to an aerosol of 1.3 x 10(7) colony-forming units of CM5/ml died within 30 hours; pigs challenge exposed to an aerosol of 1.6 x 10(8) colony-forming units of CM5A/ml survived. The average thickness of the capsular layer was 137 nm in strain CM5 and 53 nm in strain CM5A in bacteria treated with homologous antibody and examined by transmission electron microscopy. Similarly, capsular material binding polycationic ferritin was found in colonies of strain CM5, but not in strain CM5A. The ratio of hexosamine to protein in extracted capsule of CM5 was more than twice that of CM5A. The polyacrylamide gel electrophoretic profile of the lipopolysaccharide, outer membrane proteins, and whole cell proteins did not differ between the 2 strains. Also, the amount of cytotoxin or endotoxin produced by the 2 strains during the logarithmic growth phase was not different. The electrophoretic profile of restriction endonuclease digested DNA was similar, with the exception of bands in the 750- and 620-basepair regions. It was concluded that attenuation of strain CM5A during in vitro passage was a result of reduced capsule production and that encapsulation is an important virulence determinant of A pleuropneumoniae, serotype 1.

Actinobacillus↗
PubMed1990

Analysis of southern Ontario Actinobacillus (Haemophilus) pleuropneumoniae isolates by restriction endonuclease fingerprinting.

Isolates of Actinobacillus (Haemophilus) pleuropheumoniae were studied by restriction endonuclease fingerprinting (REF) analysis using the enzymes BamHI and HindIII. Restriction fragments were resolved by polyacrylamide gel electrophoresis and visualized by silver staining. Except for serotypes 1 and 9, reference strains of A. pleuropneumoniae serotypes 1 to 10 had clearly distinguishable REF profiles. Analysis of REF profiles of southern Ontario field isolates revealed limited heterogeneity amongst isolates of serotype 1 or serotype 5. The REF profiles of the serotype 7 isolates studied showed greater variation. Heterogeneity could not be correlated with the presence of plasmids nor with antibiotic resistance. Limited heterogeneity could also be detected amongst REF profiles of A. pleuropneumoniae isolates recovered from a closed herd suggesting that there is a small amount of genetic variation within clonal populations.

Actinobacillus↗
PubMed1990

Capsular polysaccharide antigens for detection of serotype-specific antibodies to Actinobacillus pleuropneumoniae.

Capsular polysaccharides (CPS) of serotypes 1, 2, 5 and 7 of Actinobacillus (Haemophilus) pleuropneumoniae were obtained from 18 h culture supernatants by precipitation with hexadecyltrimethyl-ammonium bromide (Cetavlon) followed by extraction with sodium chloride and reprecipitation in ethanol. These crude extracts, and portions purified further by phenol extraction to remove contaminating proteins, were evaluated as antigens for the detection of serotype-specific antibodies to A. pleuropneumoniae in sera from immunized rabbits and swine by an enzyme-linked immunosorbent assay. The crude extracts reacted strongly with homologous antisera, but except for serotype 1 showed considerable cross-reactivity with antisera to other serotypes. Phenol extraction greatly improved the serospecificity of the antigens from serotypes 1, 7 and, to a lesser extent, 5. The serotype 2 CPS antigen showed poor reactivity following phenol extraction, and did not appear as useful for detection of serotype-specific antibodies.

Actinobacillus↗
PubMed1990

Epidemiology of Haemophilus somnus in young rams.

The prevalence of Haemophilus somnus in the prepuce of young rams was examined. Of 473 rams entering Record of Performance (ROP) stations at 50 days of age, 43 (9.1%) were positive. Average daily gain was not affected by Haemophilus status, but was influenced by breed of ram. Suffolks were predicted to gain 0.515 kg daily compared to 0.427 kg for a group combining all other breeds. Using logistic regression to identify risk factors for individual H. somnus infection, rams in 1989 were 0.382 times as likely to be infected as rams in 1988, and Suffolks were 0.314 times as likely to be infected as the other breeds group, but these factors were not significant at the flock level. Of 80 eligible flocks of origin, 22 (27.5%) were classified as infected with H. somnus, based on rams submitted to the ROP station. Infected flocks contributed 133 rams, 43 (32.3%) of which were positive. There was no association between H. somnus status and lambing percent of the percent of abortions and stillbirths, but there was a statistically significant association with the percent of ewes which failed to lamb. In the model developed, 6% of the bred ewes in noninfected flocks failed to lamb, compared to a rate of 12% in infected flocks. These results suggest H. somnus may influence ewe fertility earlier, rather than later in gestation. Purchasing replacement animals and having cattle on the farm were risk factors for Haemophilus infection in the flock. Where replacements had been purchased within the previous year, the risk of flock infection rose 8.5 times, and on farms having cattle as well as sheep, the risk rose 13.2 times.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Cytotoxicity of Mycoplasma mycoides subspecies mycoides for cultured endothelial cells.

Toxic effect of 5 SC- and 4 LC-type strains of Mycoplasma mycoides subspecies mycoides has been demonstrated in cultured endothelial cells. The SC strains are agents of contagious bovine pleuropneumonia and presumably specific for cattle although occasionally isolated from goats. The LC strains produce an acute septicemic disease in goats and a few strains have been reported in cattle. The tissue culture cytotoxic dose causing 75% cell death (TCCD75) was calculated for each strain. Cytotoxicity ranged from 0.9 X 10(9) to 12.0 X 10(9) when strains were tested in bovine endothelial cells with the SC strains being twice as cytotoxic as the LC strains on average. Strains G175/78 and D44 representing the most cytotoxic SC and LC strains respectively, were selected for comparative experiments using bovine, caprine and porcine endothelial cells, bovine embryonic lung fibroblast cells (BELF) and the bovine cell line Madin-Darby kidney cells (MDBK). Strain G175/78 was significantly more cytotoxic for bovine endothelial cells than caprine and porcine, suggesting that the cytotoxicity reflects specificity for the bovine species. This strain was also cytotoxic for BELF but not for MDBK cells indicating that not all bovine cells are susceptible. Conversely, cytotoxicity of strain D44 was not significantly different in any of the endothelial cells tested, although cytotoxicity for BELF was significantly different, the cytotoxicity of the LC strains seems to be of less specificity.

Animals↗
PubMed1989

Adherence of Mycoplasma mycoides subspecies mycoides to cultured endothelial cells.

The LC- and SC-type strains of Mycoplasma mycoides subspecies mycoides were examined for adherence to guinea pig erythrocytes and bovine and caprine endothelial cells. The LC-type strains but not the SC-type strains adsorbed guinea pig erythrocytes and caprine endothelial cells. Difference in cytoadherence was observed between strains of the LC-type. The interaction between the most adherent LC-type strain and caprine endothelial cells was examined by transmission and scanning electron microscopy.

Animals↗
PubMed1989

Immunoserological comparison of 104-kilodalton proteins associated with hemolysis and cytolysis in Actinobacillus pleuropneumoniae, Actinobacillus suis, Pasteurella haemolytica, and Escherichia coli.

A homologous polyclonal antibody was produced in a rabbit to the 104-kilodalton (kDa) protein hemolysin of Actinobacillus pleuropneumoniae serotype 1 strain CM-5. In immunoblots, this antibody recognized a similar 104-kDa protein produced in culture supernatants by A. pleuropneumoniae serotypes 1 to 12 and taxon "Minor group" in addition to Pasteurella haemolytica, Actinobacillus suis, and alpha-hemolysin-producing Escherichia coli (but only weakly in the latter two organisms). These results were reproduced by using a mouse monoclonal antibody to the CM-5 104-kDa protein hemolysin, except that the monoclonal antibody bound more strongly to the alpha-hemolysin produced by E. coli, only weakly to the 104-kDa protein produced by "Minor group," and not at all to any extracellular antigens produced by A. suis. Pigs experimentally infected with A. pleuropneumoniae serotypes 1 to 10 and A. suis produced an antibody that recognized the 104-kDa hemolysin produced by CM-5. A pig challenged with a "Minor group" strain did not have such antibodies. Rabbit antiserum produced against the leukotoxin of P. haemolytica and alpha-hemolysin-producing E. coli also recognized the CM-5 hemolysin, but the latter only weakly. The hemolytic activity produced by CM-5 in culture supernatant was neutralized strongly by the pig serum to serotypes 1, 2, 5, 6, 9, and 10 and A. suis, only partially by serotype 8 antiserum and the rabbit antiserum to P. haemolytica leukotoxin, and not all by the antiserum to serotypes 3, 4, and 7 and "Minor group" and the E. coli alpha-hemolysin. These results indicate that a similar but not identical 104-kDa protein is produced in vitro and in vivo by all serotypes of A. pleuropneumoniae and may be related to cytolysins produced by other gram-negative bacteria.

Actinobacillus↗
PubMed1989

Molecular cloning and characterization of a hemolysin gene from Actinobacillus (Haemophilus) pleuropneumoniae.

This article describes the molecular cloning and expression of a hemolysin gene from a serotype 1 strain of Actinobacillus pleuropneumoniae. The hemolysin was a thermolabile protein with an apparent molecular weight of 29,500 (29.5K hemolysin). Unlike expression of the recently described 105K hemolysin of A. pleuropneumoniae (J. Frey and J. Nicolet, FEMS Microbiol. Lett. 55:41-46, 1988), expression of this hemolysin was not regulated by Ca2+. Antiserum prepared against the 105K hemolysin did not neutralize the activity of the 29.5K hemolysin; conversely, antiserum prepared against the 29.5K hemolysin did not neutralize the activity of the 105K hemolysin. The hemolytic activity was not neutralized with antisera against hemolytic Escherichia coli, Streptococcus agalactiae, or purified streptolysin O, but antisera prepared against recombinants containing the 29.5K gene and convalescent pig sera abrogated hemolytic activity. Although hemolytic activity could be detected in several strains of E. coli K-12 and in minicells expressing several different constructs encoding the 29.5K hemolysin, we could not rigorously exclude the possibility that the gene which we have isolated encodes a regulator of hemolytic activity rather than a hemolysin per se.

Actinobacillus↗
PubMed1989

Identification of the heat-labile hemolysin of Actinobacillus pleuropneumoniae serotype 1.

The heat-labile hemolysin of Actinobacillus pleuropneumoniae serotype 1 strain CM-5 was partially purified using ammonium sulfate precipitation and gel permeation chromatography. This partially purified material was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and blotted onto nylon filters. The filters were treated with convalescent pig serum and subsequently with CM-5 culture supernatant containing active hemolysin. A 104 kd peptide was identified as the hemolysin because it bound antibodies in convalescent pig serum which cross-linked active hemolysin. The same 104 kd protein when injected into a rabbit produced neutralizing antibodies to the CM-5 hemolysin in culture supernatant.

Actinobacillus↗
PubMed1989

The frequency, distribution and effects of antibodies, to seven putative respiratory pathogens, on respiratory disease and weight gain in feedlot calves in Ontario.

During 1983-85, 279 calves requiring treatment for bovine respiratory disease and 290 comparison (control) animals from 15 different groups of feedlot calves were bled on arrival and again at 28 days postarrival. Their sera were then analyzed for antibodies to seven putative respiratory pathogens. On arrival, the prevalences of indirect agglutination titers to Pasteurella haemolytica, P. haemolytica cytotoxin, Mycoplasma bovis and M. dispar were greater than 50%, the prevalence of titers to bovine virus diarrhea virus (BVDV) was approximately 40%, and the prevalences of titers to infectious bovine rhinotracheitis virus (IBRV), bovine respiratory syncytial virus (RSV) and parainfluenza virus type 3 (PIV3) were all below 25%. Seroconversion during the first month after arrival occurred in more than half the calves to P. haemolytica cytotoxin, PIV3 and RSV. Seroconversion of agglutination titers to P. haemolytica, Mycoplasma and BVDV occurred in about 40% of calves, and seroconversion to IBRV was infrequent (less than 5%). Initial titers were negatively correlated to subsequent titer changes within organism. Initial titers, and titer changes between organisms were essentially independent. Light calves had an increased risk of being selected for treatment for respiratory disease. Seroconversion to P. haemolytica cytotoxin, RSV and BVDV were predictive of respiratory disease cases, explaining approximately 69% of all respiratory disease cases in the feedlots. It was not possible to accurately predict weight gain or relapse from the serological data.

Animals↗
PubMed1989

Plasmid mediated antimicrobial resistance in Ontario isolates of Actinobacillus (Haemophilus) pleuropneumoniae.

The genetic basis of antimicrobial resistance in Ontario isolates of Actinobacillus (Haemophilus) pleuropneumoniae was studied. Two Ontario isolates of A. pleuropneumoniae were found to be resistant to sulfonamides (Su), streptomycin (Sm) and ampicillin (Amp). Resistance to Su and Sm was specified by a 2.3 megadalton (Mdal) plasmid which appeared to be identical to pVM104, which has been described in isolates of A. pleuropneumoniae from South Dakota. Southern hybridization showed that the 2.3 Mdal Su Sm plasmid was highly related to those Hinc II fragments of RSF1010 known to carry the Su Sm genes, but was unrelated to the remainder of this Salmonella resistance plasmid. Resistance to Su and Amp was specified by a 3.5 Mdal plasmid and appeared identical to pVM105 previously reported. The beta-lactamase enzyme had an isoelectric point of approximately 9.0. Southern hybridization showed no relationship to the TEM beta-lactamase. A third isolate of A. pleuropneumoniae was found to be resistant to chloramphenicol (Cm), Su and Sm by virtue of a 3.0 Mdal plasmid which specified a chloramphenicol acetyl transferase. We conclude that resistance to Su, Sm, Amp and Cm is mediated by small plasmids in A. pleuropneumoniae. Although the Su and Sm resistance determinants are highly related to those found in Enterobacteriaceae, the plasmids themselves and the beta-lactamase determinant are different.

Actinobacillus↗
PubMed1988

An epizootic of Mycoplasma ovipneumoniae infection in captive Dall's sheep (Ovis dalli dalli).

In late spring of 1986, 10 of 23 Dall's sheep (Ovis dalli dalli) at the Metropolitan Toronto Zoo were moved to a new exhibit, where all developed severe respiratory signs refractory to anthelmintic and antibiotic therapy. In July, two animals died with chronic active bronch-pneumonia, and a third was euthanized because of pneumonia several months later. Bacteria were not isolated from the lungs of the first, steptococci and Pasteurella hemolytica were isolated from the other two, respectively; Mycoplasma ovipneumoniae was isolated from both. Pulmonary lesions in all three sheep were consistent with Mycoplasma sp. infection. Nasal swabs of the remaining animals yielded no consistent bacterial isolates; however, four of eight sheep were positive for M. ovipneumoniae. Viral cultures yielded an as yet unidentified herpesvirus. Sheep in the original and new herds had no serologic titers to parainfluenza-3, equine viral rhinopneumonitis, or infectious bovine rhinotracheitis, and had variable titers against bovine respiratory syncytial virus. No titers against M. ovipneumoniae were present in 13 sheep still in the original exhibit, but titers varied from 1:32 to 1:256 in eight pneumonic sheep. Sera taken from three sheep before or early in the outbreak were all negative for antibody to M. ovipneumoniae. Two of the affected Dall's sheep had been in contact with domestic sheep in the winter of 1985-1986, and M. ovipneumoniae was subsequently cultured from the domestic flock. Exposure to a new pathogen, and environmental and social stress in a new exhibit may have resulted in this severe disease in Dall's sheep.

Animals↗
PubMed1988

Virulence differences among three strains of Haemophilus somnus following intratracheal inoculation of calves.

Pneumonia was induced in four month old Holstein calves by intratracheal inoculation of 1 x 10(9) colony forming units of Haemophilus somnus. Twenty calves were divided into four groups of five and challenged with a pneumonic strain (Group 1), an encephalitic strain (Group 2), a preputial strain (Group 3), or a placebo (Group 4). The clinical score, neutrophil count, respiratory rate, and temperature were significantly increased in group 1 by day 1 postinoculation (P less than 0.05) and maintained until day 6 postinoculation (P less than 0.05). The macroscopic pathological changes were significantly greater in group 1 (P less than 0.05). Haemophilus somnus was consistently isolated from pneumonic tissue of group 1 only. Groups 2 and 3 had mild transient increases in all parameters measured and macroscopically only small focal lesions were present. It is concluded that virulence differences exist between H. somnus strains following intratracheal challenge of bovine lungs.

Animals↗
PubMed1988

Evaluation of heat-sensitive, neutrophil-toxic, and hemolytic activity of Haemophilus (Actinobacillus) pleuropneumoniae.

Cytotoxic and hemolytic activity of Haemophilus (Actinobacillus) pleuropneumoniae serotype 1 strain CM5 was investigated because of the potential role as a virulence determinant. Viable bacteria were toxic for porcine and bovine neutrophils, whereas bacteria killed by heat treatment at 60 C for 1 hour were not. Similarly, bacteria-free culture supernatant was cytotoxic and hemolytic in assays that used porcine neutrophils and erythrocytes, whereas supernatant treated at 60 C for 1 hour had no activity. Erythrocytes from various species were susceptible to the hemolytic activity of bacteria-free culture supernatant, with ovine and bovine erythrocytes being most sensitive. The neutrophil-toxic and hemolytic activity of bacteria-free culture supernatant was inhibited by cholesterol and oxygen and abolished after trypsin digestion. The neutrophil-toxic and hemolytic activity was preserved during storage at or less than 4 C, but was lost rapidly at 56 C or 80 C. Neutralizing antibodies were demonstrated in serum of pigs and rabbits immunized with 10-fold concentrated culture supernatant of strain CM5 and in field pigs that had recovered from natural infection with H pleuropneumoniae serotype 1. Bacteria-free culture supernatants of 18 strains, including H pleuropneumoniae serotypes 1 through 10, Actinobacillus suis, and Haemophilus taxon minor group, were tested for heat-sensitive, neutrophil-toxic, and hemolytic activity. Fifteen strains were neutrophil toxic, but only 10 of these were hemolytic. Haemophilus pleuropneumoniae, serotype 1, strain VLS557; serotype 5, strain K17; and Haemophilus taxon minor group strain 33PN were neither cytotoxic nor hemolytic.

Animals↗