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Biomedical subjects

L A Devriese

Publications and source records attributed to L A Devriese.

At least 109 records · Page 6Linked to original sources

Immunity in pigeons against homologous and heterologous serotypes of Streptococcus bovis after infection.

Groups of 20, 20 and 10 pigeons were intravenously inoculated with 1 x 10(9) CFU of a Streptococcus bovis serotype 1, 2 and 3 strain, respectively. Groups which received the highly virulent serotypes 1 or 2 strains were treated with antibiotics starting from 2 days post inoculation in order to prevent the development of clinical signs. Pigeons inoculated with the low virulence S. bovis serotype 3 strain were left untreated. Another group of 10 non-inoculated pigeons was used as challenge control. Four weeks later, pigeons were challenged intravenously with S. bovis serotype 1. Morbidity after challenge infection was 19%, 36% and 70% in groups previously inoculated with serotypes 1, 2 and 3, respectively, whereas it was 100% in the control group. Results demonstrate that pigeons developed significant protective immunity to S. bovis serotype 1 septicaemia following infection with S. bovis serotype 1 and 2 strains but not after infection with the serotype 3 strain. Protection did not correlate with the presence of antibodies as detected in ELISA.

Animals↗

Rapid differentiation of avian Haemophilus-like strains by their whole-cell carbohydrate patterns.

The whole-cell carbohydrate patterns of 14 Haemophilus-like strains isolated from diseased birds were examined by capillary gas chromatography/mass spectrometry. The analysis of the peracetylated aldononitrile and O-methyloxime derivatives allowed the differentiation between the phenotypically and genetically different isolates. Starting from a pure culture the procedure needs only 5 hours for the preparation of the samples and 30 minutes for subsequent analysis and is of special value for rapid diagnosis.

Animals↗

Serotyping and quantitative determination of in vitro antibiotic susceptibility of Actinobacillus pleuropneumoniae strains isolated in Belgium (July 1991-August 1992).

One hundred and ninety nine Actinobacillus pleuropneumoniae isolates obtained from the respiratory tract of pigs in Belgium (1991-1992) were serotyped using slide agglutination and slide precipitation tests. Biotype 1-serotype 2 and 3 strains were isolated most frequently and represented 36% and 21% of the isolates, respectively. Serotype 9 and serotype 5B strains represented 15% and 10% of the total number of isolates, respectively, while serotypes 7, 8, 10 and 11 were isolated only sporadically. Serotypes 5B, 10 and 11 were isolated for the first time in Belgium. Biotype 2 strains represented 12.5% of the total number and all belonged to the serotype 2. The in vitro susceptibility of 138 strains was determined for ten commonly used antibiotics. For three antibiotics, ampicillin, chloramphenicol, and oxytetracycline, a bimodal distribution of strain sensitivities was observed. A total of 17 strains (12%) were considered to have acquired resistance to one or more of these antibiotics.

Actinobacillus Infections↗

Prevalence of Streptococcus bovis in racing pigeons.

The prevalence of S. bovis in the intestinal tract of healthy racing pigeons was determined. Crop and cloaca swab samples obtained from 810 pigeons from 14 different lofts and from 122 pigeons that were presented for routine health control were examined for the presence of S. bovis. Pooled faecal samples were also obtained from pigeons in 82 different pigeon lofts. S. bovis was isolated from crop or cloaca samples of approximately 40% of pigeons of all ages by direct culture and from 80% of the pooled faecal samples by enrichment culture. In a longitudinal study, crop and cloaca samples were collected every 3 months from pigeons in seven different pigeon lofts. The prevalence of S. bovis in these pigeons ranged from 0 to 100%. The carriage rate was not related to the season or to the age of the pigeons. The prevalence of S. bovis in organ lesions of pigeons examined at necropsy was investigated over a 35-month period. S. bovis was isolated from 10% of the birds examined. The incidence of S. bovis septicaemia was significantly higher in January to August than in September to December. It was concluded that S. bovis is an opportunistic pathogenic agent in pigeons.

Animals↗

Identification and composition of the streptococcal and enterococcal flora of tonsils, intestines and faeces of pigs.

Streptococcus suis was the most frequent Streptococcus spp. in pig tonsils, followed by the beta-haemolytic porcine 'equisimilis' ecovar of Strep. dysgalactiae. The intestinal streptococcal flora was composed of Strep. bovis, Strep. hyointestinalis and Strep. suis. Many of these intestinal Strep. suis belonged to a beta-glucuronidase-negative biotype which is infrequent in lesions. Nearly half of the strains presumptively identified as Strep. alactolyticus produced acid from lactose. This species was not found in tonsils and intestines but was about equally prevalent as Strep. hyointestinalis in pig faeces and rectal swabs. Other streptococci were rare in this material. Enterococci were much less frequently identified than streptococci in tonsils and faeces. In intestinal samples Enterococcus faecalis, Ent. faecium, Ent. hirae and Ent. cecorum were most frequently found. In faeces Ent. faecium was the most prevalent enterococcus. The characteristics of the less well known species Strep. alactolyticus and Strep. hyointestinalis are described in detail, and guidelines for their differentiation from Strep. bovis and Strep. suis given.

Animals↗

Characterization and identification of Vagococcus fluvialis strains isolated from domestic animals.

Strains of Vagococcus fluvialis, a species of Gram-positive catalase-negative cocci, related to the genera Enterococcus and Carnobacterium, were isolated from various lesions of pigs, from lesions and tonsils of cattle and cats and from tonsils of a horse. Most lesion strains were isolated in mixed culture from animals with disease conditions unrelated to coccal infection. Certain differences with the species description of Vagococcus fluvialis were found: only a proportion of the strains was motile; many strains gave positive reactions to Voges-Proskauer, alkaline phosphatase and leucine arylamidase tests or produced acid from galactose and D-tagatose. SDS-PAGE of whole-cell protein patterns, however, confirmed the phenotypic identification. Guidelines for identification of Vagococcus fluvialis are given and an emended description of the species is proposed.

Animals↗

Influence of the oestrous cycle on experimental intrauterine E. coli infection in the sow.

The influence of the oestrous cycle on the onset of endometritis in the sow was studied. Ten pubertal, unmated gilts of the Belgian Negative Landrace were used. Nine gilts were inoculated into the uterus by laparotomy with a suspension of an E. coli strain isolated from the uterus of a discharging sow from a herd having many problems with vaginal discharge and a lowered fertility. One gilt was as a control inoculated with 2 ml of a PBS-solution. All sows inoculated during dioestrus developed clinical symptoms, but only 1 of the 5 gilts inoculated at standing oestrus developed a vaginal discharge. These data confirm the hypothesis that the stage of the oestrous cycle has an important influence on the onset of endometritis. The resistance to E. coli infections was higher when the gilts were inoculated during oestrus.

Animals↗

Flavobacterium meningosepticum, a pathogen in birds.

Five bacterial isolates were recovered from various diseased birds (chickens, a pigeon, and a zebra finch) and were identified as Flavobacterium meningosepticum. Four of them were isolated in pure or nearly pure culture of samples from internal organs, and one strain was isolated in mixed culture of a tarsal joint fluid sample. Except for the last case, there was no evidence of other disease agents. By using phenotypic, chemotaxonomic, and genomic methods, the strains were taxonomically characterized and could not be differentiated from the human clinical reference strains of the species. Two avian strains were different in their phenotypic behaviors and constituted another genotypic subgroup. In general, all F. meningosepticum strains constituted a single species which was easily differentiated from biochemically similar species and phylogenetically closely related taxa.

Animals↗

Erysipelothrix tonsillarum isolated from dogs with endocarditis in Belgium.

Five strains of Erysipelothrix tonsillarum were isolated from dogs with endocarditis in Belgium. The identity and validity of the species was proved by serotyping, and biochemical and pathogenicity tests. All the isolates belonged to serovar 7 (E tonsillarum serovars); they produced acid from saccharose but did not induce any clinical sign of erysipelas in swine. These results suggest that some strains of E tonsillarum are a canine pathogen.

Animals↗

Molecular taxonomic studies of Actinomyces-like bacteria isolated from purulent lesions in pigs and description of Actinomyces hyovaginalis sp. nov.

The 16S rRNA gene sequence of some Actinomyces-like bacteria isolated from purulent lesions in pigs was determined. A comparative analysis of the rRNA sequence data revealed that the bacteria are members of the genus Actinomyces, but are phylogenetically distinct from Actinomyces suis. On the basis of our findings and the results of previous phenotypic studies it is formally proposed that the bacteria from pigs should be designated a new species, Actinomyces hyovaginalis.

Actinomyces↗

In vitro susceptibility of Clostridium perfringens isolated from farm animals to growth-enhancing antibiotics.

Minimal inhibitory concentration (MIC) determinations were carried out with seven growth-enhancing antibiotics against 95 Clostridium perfringens field isolates obtained during 1991 and 1992 from poultry, pigs and calves. All were resistant to 64 micrograms ml-1 of the bambermycin antibiotic, flavomycin (flavophospholipol) and susceptible to avoparcin (MIC90 0.25 micrograms ml-1), avilamycin (MIC90 0.5 micrograms ml-1) and salinomycin (MIC90 < or = 0.12 micrograms ml-1). Acquired resistance against bacitracin was detected in some isolates from poultry and bovines and resistance to tylosin and virginiamycin in some strains from all species investigated. Overall, the prevalence of resistance was comparable to the low levels recorded in 1979 in Cl. perfringens isolates from the same animal host species.

Animals↗

Prevalence of antibodies to Streptococcus bovis serotype 1 in racing pigeons.

Indirect ELISA techniques for the detection of antibodies to S. bovis serotypes 1, 2 and 3 in pigeon plasma were developed. Whole formaldehyde-inactivated bacteria were used as coating antigens. Bound antibodies were detected with peroxidase-conjugated rabbit anti-pigeon serum and OPD and H2O2 as chromogen and substrate, respectively. ELISA was used to determine the prevalence of antibodies to S. bovis serotype 1 in healthy Belgian racing pigeons. Antibodies were demonstrated in 83 (= 37%) of 225 samples tested. Results indicate that pigeons may build up plasma antibodies in the absence of clinical signs resembling septicaemia.

Animals↗

Streptococci and enterococci associated with tonsils of cattle.

Streptococcus suis, Streptococcus bovis and the mastitis pathogens Streptococcus dysgalactiae and Streptococcus uberis were the most frequently occurring streptococci in tonsils of cattle. Streptococcus suis dominated in samples from calves between 1 month and 1 year of age, but was much less frequent in calves less than 1 month old. The mastitis pathogen Strep. dysgalactiae was found more often in calves than in older animals. Enterococci were relatively rare, except in the youngest age group. Nearly one third of the strains examined could not be identified to known species.

Animals↗

Characteristics of bovine Staphylococcus aureus with special regard to clumping factor activity.

The occurrence of the following groups of bovine Staphylococcus aureus with characteristic patterns of biochemical reactions and sensitivities to phages was confirmed by the present investigation of 662 isolates from the udders of cows in 53 dairy herds: (1) host-specific variety (v) bovis, (2) not alloted strains with the basic marker, crystal violet type A (group na CV A), (3) group na CV C. The latter was split into three subgroups clearly differing in phage susceptibility patterns: I/119, I without 119 and III, respectively. Lack of clumping factor activity occurred in 323 out of 346 (93%) phage pattern I/119 strains examined while most or all isolates of the other groups of bovine strains proved to be clumping-positive.

Animals↗