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Plasmid profiles of Moraxella bovis isolates.

Two-hundred isolates of Moraxella bovis were selected at random and examined for the presence of plasmid DNA by a rapid alkaline-detergent lysis method. All isolates contained from 1 to 6 plasmids, with varying agarose-gel electrophoretic migration patterns. Most (80%) isolates carried 2 to 4 plasmids, which ranged in molecular weight from 2.6 to 80 megadaltons. Seemingly, plasmid profiles can be used as a simple, reliable epizootiologic tool to establish a strain identification scheme for M bovis.

Animals↗

Moraxella bovis hemagglutinins: effect of carbohydrates, heating and erythrocytes.

Several properties of the adhesins of eight isolates of Moraxella bovis recovered from cattle suffering from infectious keratoconjunctivitis, were studied. Adhesions were detected through autoagglutination in saline and hemagglutination. Autoagglutinating strains agglutinated red blood cells of the chicken, rabbit, sheep and swine, but not those of the guinea pig. The adhesins were not inhibited by D-mannose or D-galactose and resisted heating at 100 degrees C for 15 minutes. Magnesium chloride at a final concentration of 10% inhibited autoagglutination and hemagglutination. The value of the hemagglutination test for monitoring synthesis of fimbriae by M. bovis, is discussed.

Adhesins, Bacterial↗

Serologic response of vaccinated cattle to strains of Moraxella bovis isolated during epizootics of keratoconjunctivitis.

In studies to determine whether there were antigenic differences between strains (isolates) of Moraxella bovis, the sera from vaccinated calves were tested with isolates of M bovis while the calves were experiencing epizootics of infectious bovine keratoconjunctivitis (IBK). Before the epizootics of IBK, the calves were intramuscularly vaccinated with a formalin-killed autogenous M bovis bacterin. During the epizootics, the eyes were examined by cultural technique, and isolates which were obtained were categorized by catalase activity, source (diseased or nondiseased eyes), and reactivity with the various sera. The serum reactivity of the isolates was compared with that of the vaccinal strain. The vaccinal strain and 8 of the 1 5 selected isolates obtained during the 1974 epizootic were catalase negative. Seven of the 15 isolates from the 1974 epizootic and all of the selected isolates from the 1975 epizootic were catalase positive. A significantly higher (P less than 0.01) percentage of calf sera were serologically reactive with the vaccinal strain and other catalase-negative isolates (45.0%) than with catalase-positive isolates (34.8%). The results, although not definitive, suggest that there may be antigenic differences among strains of M bovis. These differences should be considered when cattle are vaccinated against IBK under natural conditions of exposure.

Animals↗

Comparison of the virulence of various strains of Moraxella bovis.

The relative virulence of various strains of Moraxella bovis (M. bovis) was studied using the eyes of mice and cattle. The investigation consisted of three separate experiments. Experiments I and II involved a study on the effects of (1) different methods of growth and (2) serial blood agar passaging on the virulence of M. bovis. Experiment III involved a study on the relative virulence of different strains of M. bovis and M. bovis-like organisms. Strains of M. bovis and M. bovis-like organisms varied in their pathogenicity for mice. However, different methods for preparation of exposure cultures of M. bovis did not influence the disease produced.

Agar↗

The pathophysiological effects of Moraxella bovis toxins on cattle, mice and guinea pigs.

In three experiments, cattle, mice and guinea pigs were inoculated with viable cultures of Moraxella bovis or fractions of this organism. Fractions were obtained by disruption of cells with a fractionator at 20,000 pounds per square inch, and separating the cell wall and cell sap fractions by differential centrifugation. Cell sap fractions were further separated by ultra-centrifugation, heating and precipitation with (NH(4))(2) SO(4). Different fractions induced different pathophysiological manifestations. The cell wall fractions caused localized lesions (necrosis) at the site of injection, and emphysema and congestion of the lungs. Cell sap fractions induced a "shock syndrome," as well as hemorrhage and inflammation of the intestines, hemorrhage and congestion of lymph nodes, liver, adrenal and spleen. Cell sap also induced conjunctivitis in mice and guinea pigs, and periocular edema, myosis, ocular pruritus and lacrimation in cattle. The authors suggest that M. bovis probably produces endotoxins and exotoxins as well as possibly a specific oculopathic substance, but more definitive work is needed to confirm this. They caution that consideration of these toxins should be made in any application of M. bovis for vaccines or other immunological studies.

Animals↗

Infectious bovine keratoconjunctivitis: enhancement of Moraxella bovis pili immunogenicity with diphtheria-tetanus toxoids and pertussis vaccine.

A study was conducted to determine whether diphtheria-tetanus-toxoids and pertussis vaccine (DPT) would enhance the immunogenicity of homologous Moraxella bovis pili fractions. Thirty-six calves were divided into 4 groups (I, II, III, and IV) of 9 calves each. Calves in group I were not vaccinated and served as controls. Calves in group II were vaccinated with pili fractions only. Calves in group III were vaccinated with DPT only. Calves in group IV were vaccinated with DPT and pili. Vaccination consisted of 2 inoculations, 21 days apart. Fourteen days after the last vaccinal inoculation was done, the eyes of all calves were exposed to a hemolytic homologous strain of M bovis. The percentage of eyes with disease was significantly less in calves given DPT and pili (P less than 0.001) and calves given pili only (P less than 0.05) than in calves given DPT only or nonvaccinated calves. The lesions were less severe in calves vaccinated with pili only than in calves not vaccinated with pili. Serologic results also showed a positive relationship between the development of serum antibodies against pili and immunity. The results indicate that DPT enhanced the immune response and if used as an adjuvant, might be useful in the development of a vaccine against infectious bovine keratoconjunctivitis.

Animals↗

Serological characterization of strains of Moraxella bovis using double immunodiffusion.

Sera were produced in rabbits against nine Moraxella bovis strains isolated in Brazil and three in the United States. Antigens were prepared for double immunodiffusion tests by thawing concentrated suspensions of the strains. Sera were tested against homologous and heterologous antigen preparations by the double immunodiffusion method. Sera showing precipitin bands with heterologous antigens were absorbed. Antigenic differences were detected between the strains and a provisional grouping of strains of M. bovis was suggested on the basis of antigenic composition. Differences between isolates from different geographical locations were found and some strains appeared antigenically more complex than others. The relevance of this work to vaccine production was suggested.

Animals↗

Surface polysaccharide of Moraxella non-liquefaciens identical to Neisseria meningitidis group B capsular polysaccharide. A chemical and immunological investigation.

In whole cell preparations of 27 nonmucoid strains of Moraxella nonliquefaciens neuraminic acid was detected by gas chromatography (GC) in 16 (59%) of the strains. Seven neuraminic-acid-containing strains were tested for agglutination with diagnostic group-specific meningococcal antisera produced in rabbits, and all were positive with group B serum. Counter-immunoelectrophoresis of bacterial suspensions of the three strains with the strongest reaction with such anti-group B serum gave distinct precipitation lines. When tested by double immunodiffusion in agarose with monoclonal antibody to meningococcal group B polysaccharide, suspension of a strain of M nonliquefaciens gave identity reaction with a strain of Neisseria meningitidis, and reacted even more strongly than the latter. Phenol extracts of M nonliquefaciens strains generally contained higher amounts of neuraminic acid than N meningitidis group B strains. Neuraminic-acid-containing polysaccharides of M nonliquefaciens strains sedimented more slowly by ultra-centrifugation than the group-specific B polysaccharide of N meningitidis strains. They also reacted more strongly with a monoclonal anti-group B antiserum than did N meningitidis group B capsular polysaccharide in an antibody binding inhibition test (solid phase radioimmunoassay). Immunological reactivity of the polysaccharides of both species was lost if extraction was performed with unbuffered phenol at 68 degrees C, instead of with neutral phenol at 4 degrees C. The results show that several strains of M nonliquefaciens, often inhabiting the human nose, have high levels of a surface polysaccharide chemically and immunologically closely similar to N meningitidis group B capsular polysaccharide. The cross-reactivity may have immunological implications for meningococcal disease.

Chromatography, Gas↗

Effects of aflatoxin ingestion on the development of Moraxella bovis infectious bovine keratoconjunctivitis.

A study was conducted to determine whether measured doses of aflatoxin given under different schedules would influence the pathogenesis of Moraxella bovis induced infectious bovine keratoconjunctivitis (IBK). Calves were allotted to 4 groups (groups I-IV) of 9, 9, 9, and 8 calves, respectively. Group I calves were given aflatoxin for 11 consecutive days starting 5 days before their eyes were exposed to M. bovis. Group II calves were given aflatoxin for 5 consecutive days starting 7 days after their eyes were exposed to M. bovis. Group III calves were given aflatoxin for 5 consecutive days starting 21 days after their eyes were exposed to M. bovis. Group IV calves were not given aflatoxin; but their eyes were exposed to M. bovis on the same day as were the eyes of calves in groups I-III; these calves served as controls. Aflatoxin had little if any influence on the pathogenesis of IBK under the conditions of this study. The results did not rule out an exacerbating effect of M bovis infection on aflatoxicosis in calves. Calves with the highest concentration of aflatoxin in their blood had the more severe signs of aflatoxicosis. Possible reasons for the equivocal results are discussed.

Aflatoxins↗

Moraxella bovis hemolysin.

Moraxella bovis hemolysin was readily filterable through polycarbonate membrane filters, but not through nitrocellulose filters. The hemolysin was filterable through polycarbonate filters with pore diameters of greater than or equal to 0.015 micron (APD). Of the hemolytic activity of cell-free filtrates, 74% could be pelleted by ultracentrifugation at 100,000 X g for 2 1/2 hours. Hemolytic activity could be demonstrated in preparations of outer membrane fragments isolated from log-phase cultures. Hemolysin in M bovis broth cultures reached a maximum concentration in late logarithmic phase (4.5 hours after inoculation) and declined thereafter. Hemolysin was inactivated by heat, trypsin, formalin, and lyophilization.

Collodion↗

Serotypes and antibiotic sensitivity of Moraxella bovis isolated from an outbreak of infectious bovine keratoconjunctivitis.

Samples of conjunctival fluid of four calves, from a herd with infectious bovine keratoconjunctivitis, were collected five times at monthly intervals and from another 16 calves in the initial stages of the disease, were collected only once. Moraxella bovis was recovered from 82.3% of the samples. Twenty-six isolates were typed with polyvalent sera and 25 with monovalent sera. The antibiotic sensitivity of 13 isolates was also studied. Twenty of the 26 isolates reacted with polyvalent sera and 16 of 25 tested isolates, reacted with monovalent sera. The isolates recovered from the same animal in a different collection or from a different animal in the same collection did not always belong to the same serogroup. Different serotypes were prevalent in each collection. Differences in the antibiotic sensitivity of the isolates were also detected.

Animals↗

Surgical treatment of fungating lesion of foot due to Moraxella phenylpyruvica. Case report.

We present a case report of a man who had an abscess-like lesion on his left foot. The lesion discharged pus, enlarged, and became thicker, so that we could not differentiate the real toes from the out-growths. Moraxella phenylpyruvica and Pseudomonas putrefaciens were identified; direct agglutination tests were postive M. phyenylpyruvica. He was given antibiotics and antituberculosis therapy and had topical treatments. The foul odor disappeared with treatment, and the lesions were removed surgically 3 months later. The M. phenylpyruvica finally disappeared after the surgery. The final condition of this patient was markedly improved, although he had some residual scar contracture.

Adult↗

Chronic cholera-like lesions caused by Moraxella osloensis.

Cholera-like lesions appeared in four house-confined flocks of tom turkeys on one farm from October 30, 1980, to December 2, 1980; Moraxella osloensis was isolated from the tissues. All flocks were treated with 0.04% sulfaquinoxaline in the water for 3 days. The flocks returned to normal and had normal condemnation rates at slaughter. An experiment was conducted in which six hen turkeys were inoculated with a M. osloensis isolate. The same gross lesions were produced as seen in the field cases.

Animals↗

Laboratory model for infectious bovine keratoconjunctivitis: the pathogenicity of different strains of Moraxella bovis, pathology and ultrastructural observations.

Further studies were made using C57 mice pretreated with a corticosteroid and inoculated with Moraxella bovis by instillation, as a model for infectious bovine keratoconjunctivitis. Strains of M bovis which had previously been tested in cattle produced a generally similar range of pathogenicity when tested in mice. The pathology in the mouse model closely resembled that in cattle and the value of the model for studies on M bovis was confirmed.

Animals↗

Hemagglutination, autoagglutination and pathogenicity of Moraxella bovis strains.

Three isolates of Moraxella bovis, recovered from cattle with signs of infectious bovine keratoconjunctivitis, were tested for autoagglutinating activity, hemagglutinating activity and pathogenicity in young calves. Only the autoagglutinating and hemagglutinating isolates were pathogenic in calves. Treatment of the pathogenic isolates with magnesium chloride eliminated their pathogenic effects.

Agglutination↗

Enzyme-linked immunosorbent assay for measurement of anti-Moraxella bovis antibodies.

Antibodies of the immunoglobulin (Ig) G and IgA classes specific for Moraxella bovis in serum or lacrimal secretions of cattle were detected with an enzyme-linked immunosorbent assay, using soluble extracts of M bovis or whole organisms. The amount of detectable antibodies was influenced by the type of antigenic preparation used in the enzyme-linked immunosorbent assay. The test indicated that 2 subcutaneous inoculations of M bovis cells induce significantly (P less than 0.0001) increased anti-M bovis serum antibodies. The infection of calves with M bovis induced specific IgG antibodies in serum and predominantly IgA antibodies in lacrimal secretions.

Animals↗