Biomedical subjects

A E Sonn

Publications and source records attributed to A E Sonn.

6 recordsLinked to original sources

PubMed1993

Serogrouping of Bacteroides nodosus isolates from 62 sources in the United States.

Bacteroides nodosus isolates from 62 sources in the United States were obtained from sheep with infectious foot diseases. Serotypic analysis of these isolates revealed 21 serotypes (designated I-XXI). These serotypes were compared with British and Australian/New Zealand B nodosus strains by use of reciprocal tube agglutination tests. These tests, as well as the cross-matching tube agglutination tests of the US serotypes, resulted in arranging the US serotypes into 11 serogroups, and comparing these serogroups with their Australian/New Zealand serogroup and British serotype counterparts. Three US serogroups and 1 additional British serotype had little or no relationship to any of the Australian/New Zealand serogroups A-H (the vaccine strains). One or more of these unrelated serogroups were found in 29% of the sources studied. The most frequently found US serotype was serotype XV at 29%. The most frequently found US serogroups were the serogroups analogous to serogroup B (43.5%) and serogroup H (37%); the other serogroups were found in 22.6% or less of the sources studied. Evaluation of 3 sources revealed that multiple serotypes in a single flock are common, multiple serotypes from a single lesion are possible, B nodosus isolates obtained from goats (unlike those from cattle) appear identical to the isolates obtained from sheep, and disease can appear in vaccinated animals, even in a flock that appears to be harboring only a single serogroup-B serotype (the serogroup for which there are 3 strains in the current vaccine).

Agglutination Tests↗

PubMed1991

Electron microscopic study of Bacteroides nodosus pili and associated structures.

Surface structures of Bacteroides nodosus were examined by electron microscopy. Collodion film and chrome shadowing were used for maximizing the visualization of B nodosus pili and ring structures. The existence of B nodosus pili in foot rot lesions was confirmed. Contrary to previous reports, it was found that B nodosus pili production can be retained through serial broth transfer under certain conditions. Capsule production by B nodosus was irregular in that it could be either lacking or variable in thickness. A bacteriophage capable of infecting B nodosus also was detected.

Animals↗

PubMed1991

Monoclonal antibodies against pili of serologically distinct Bacteroides nodosus.

Several monoclonal antibodies (McAbs) against pili of Bacteroides nodosus were examined to determine their reactivity with 11 different serotypes. One McAb was identified by enzyme-linked immunosorbent assay (ELISA) analysis that bound to nine of the 11 serotypes and another that bound to the remaining two serotypes tested. In addition, some McAbs demonstrated specificity for a single serotype, while others displayed specificities for up to five other serotypes. Comparison of immunoblot analysis with the ELISA revealed that the former method was not as sensitive in that all McAbs positive by the ELISA, were not positive by immunoblot. Possible explanations of these findings are discussed. There appear to be several antigenic determinants on B. nodosus pili and considerable sharing of these determinants between pili types. The 11 serotypes analyzed by the McAbs in this report are representative of all 20 US serotypes as well as the A-set and D-set categories of Australia. Therefore, the two epitopes recognized by two of the McAbs reported herein encompass all of the currently characterized B. nodosus serotypes and may provide a basis for bivalent vaccines efficacious for all types of B. nodosus induced footrot in sheep.

Animals↗

PubMedDate not supplied

Chicken heterophil chemotaxis using Staphylococcus-generated chemoattractants.

Heterophil chemotaxis, in response to chemotactic factors generated by three different strains of staphylococcal bacteria, was measured using the modified Boyden-chamber technique. Heterophils were obtained from healthy 6-to-8-week-old broiler chickens. Each bacterial strain generated factors that were chemotactic for chicken heterophils. Factors generated by two pathogenic isolates of Staphylococcus aureus, however, induced significantly greater chemotaxis in chicken heterophils than those generated by a nonpathogenic Staphylococcus isolate.

Animals↗

PubMedDate not supplied

Heterophil chemotaxis in chickens with natural Staphylococcal infections.

Heterophil chemotaxis using heterophils isolated from the peripheral blood of five commercial broiler chickens naturally infected with staphylococcal bacteria was compared by the modified Boyden-chamber technique with chemotaxis of heterophils from two chickens from the same flock not infected with Staphylococcus (field controls) and from four healthy laboratory control broiler chickens. The infected chickens had gross and histologic lesions of staphylococcal tenosynovitis and osteomyelitis. Staphylococci were isolated from the lesions. Hematologic parameters and histologic lesions of infected chickens also were examined. Compared with field and laboratory controls, Staphylococcus-infected chickens had heterophilic leukocytosis. The heterophils of Staphylococcus-infected chickens had significantly lower chemotactic activity than both control groups in terms of random movement and directed chemotactic movement in response to stimulus. Toxic changes were observed in heterophils of some of the Staphylococcus-infected broilers.

Animals↗

PubMedDate not supplied

Comparison of the effect of different opsonins on the phagocytosis of fluorescein-labeled staphylococcal bacteria by chicken heterophils.

Heterophil phagocytosis of fluorescein-labeled staphylococcal bacteria was analyzed by flow cytometry. Opsonization with two types of normal pooled sera and staphylococcal antisera significantly increased bacterial phagocytosis compared to samples without an opsonin. The staphylococcal antisera did not significantly increase bacterial phagocytosis compared to the normal pooled sera. Opsonization appears to increase bacterial phagocytosis but specific antisera may not increase phagocytosis beyond that caused by pooled normal sera.

Animals↗