Search PubMed⌕ Search

Biomedical subjects

F Haesebrouck

Publications and source records attributed to F Haesebrouck.

At least 181 records · Page 10Linked to original sources
PubMed1994

An unusual outbreak of Streptococcus bovis septicaemia in racing pigeons (Columba livia).

In December 1991, an outbreak of Streptococcus bovis septicaemia occurred in a Belgian pigeon loft where 25 male and 25 female racing pigeons were housed. The main clinical signs included inability to fly and poor breeding results. None of the female pigeons and only one male pigeon was able to fly. Nine affected pigeons were necropsied. Histologically a tenosynovitis of the tendon of the deep pectoral muscle was observed in most of them and S bovis was isolated from the canalis triosseus or the shoulder joints of five of the nine pigeons. The pigeons were successfully treated with ampicillin administered in the drinking water for seven days.

Animals↗
PubMed1994

A simple identification scheme for coagulase negative staphylococci from bovine mastitis.

Coagulase-negative staphylococci from cases of bovine mastitis were identified to species level by using an identification scheme based on a three-plate test system which tested for DNase on DNA agar, for protease on calcium caseinate agar, and for the organism's sensitivity to novobiocin, desferrioxaminine (deferoxamine) and fosfomycin by agar diffusion tests. Testing for the inhibition of Staphylococcus delta haemolysin (Skalka 1991) can replace the protease tests.

Agar↗
PubMed1994

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↗
PubMed1994

NAD-independent Actinobacillus pleuropneumoniae strains: production of RTX toxins and interactions with porcine phagocytes.

Actinobacillus pleuropneumoniae RTX toxin (Apx) production by A. pleuropneumoniae biotype 2 (NAD-independent) serotype 2 strains was studied. Western blot analysis of culture supernatants of all biotype 2 strains tested revealed the presence of a 103 kDa protein which reacted with a monoclonal antibody against ApxIIA. This protein was also recognized by sera of pigs infected with a biotype 2-serotype 2 strain. Furthermore, antibodies that could neutralize ApxIIA were present in these sera. Proteins corresponding to ApxIA or ApxIIIA were not detected. The effects of a biotype 1-serotype 2 and a biotype 2-serotype 2 strain and their metabolites on the oxidative activity of porcine pulmonary alveolar macrophages (PAM) and polymorphonuclear cells (PMN) were compared using a chemiluminescence (CL) technique. Viable bacteria of both biotypes stimulated the production of oxygen radicals by phagocytes. CL responses were higher for the biotype 1 than for the biotype 2 strain. After having reached a peak value, the oxidative activity decreased until a total inhibition was achieved. Inactivated washed bacteria had no influence on the oxidative activity of phagocytes. In contrast, heat labile factors in culture supernatants of both biotypes stimulated and inhibited the oxidative activity of PAM in a dose-dependent manner. Dilutions of supernatant up to 1/32 of the biotype 2 strain and up to 1/512 of the biotype 1 strain were toxic for PAM, while dilutions from 1/64 to 1/128 of the biotype 2 strain and from 1/1024 to 1/4096 of the biotype 1 strain stimulated the oxidative activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus pleuropneumoniae↗
PubMed1994

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↗
PubMed1994

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↗
PubMed1994

Chemiluminescence properties of porcine pulmonary alveolar macrophages and polymorphonuclear cells.

A luminol-enhanced chemiluminescence (CL) technique was developed for porcine pulmonary alveolar macrophages (PAM) and polymorphonuclear cells (PMN). PAM were obtained from lung washings of 3 week old gnotobiotic pigs. PMN were obtained from peripheral blood by separation on a discontinuous Percoll gradient. Optimum CL signals were obtained with 10(5) PAM/tube and 5 x 10(4) PMN/tube. Stimulation indexes (SI) for PAM were approximately 10 for phorbol myristate acetate (PMA), 8 for opsonized Actinobacillus pleuropneumoniae and 3 for opsonized zymosan. SI for PMN varied from 100 to 180 for complement opsonized zymosan, from 50 to 100 for opsonized A. pleuropneumoniae and from 10 to 20 for PMA. Formyl-methionyl-phenylalanine and calcium ionophore A23187 did not stimulate the oxidative activity of PAM or PMN. PAM that had been frozen and stored in liquid nitrogen reacted as freshly obtained PAM in the CL assay; however, PMN that had been frozen lost a great deal of their ability to produce oxygen radicals after thawing. The CL technique offers new perspectives for the study of immune mechanisms in swine.

Animals↗
PubMed1994

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↗
PubMed1994

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↗
PubMed1994

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↗
PubMed1994

Comparison of the Salmonella-Tek ELISA to culture methods for detection of Salmonella enteritidis in litter and cloacal swabs of poultry.

An enzyme-linked immunosorbent assay (ELISA), using the Salmonella-Tek ELISA test system, was compared with bacteriological isolation for detection of Salmonella enteritidis phage type 4 in litter and cloacal swabs of poultry. Before ELISA, samples were enriched in tetrathionate broth for 18-24 h or in tetrathionate broth (18-24 h), followed by M-broth/novobiocine (4-6 h). The bacteriological isolation procedure included incubation in buffered peptone water and inoculation on modified semisolid Rappaport-Vassiliadis. For detection of S. enteritidis in litter samples, ELISA was more sensitive than bacteriological examination. For cloacal swabs, both techniques were equally sensitive. The two enrichment procedures gave no significant differences in ELISA results. It was concluded that the Salmonella-Tek ELISA test might be a promising test for detection of Salmonella infected poultry flocks, providing that further studies are performed to determine the cut-off value for litter and cloacal swabs of commercial flocks.

Animals↗
PubMed1994

In vivo association of Actinobacillus pleuropneumoniae serotype 2 with the respiratory epithelium of pigs.

The ability of an Actinobacillus pleuropneumoniae serotype 2 strain to associate in vivo with the epithelium of the porcine respiratory tract was investigated in a sequential study after intranasal inoculation of hysterectomy-derived and colostrum-deprived pigs. At 30 min postinoculation more than 95% of the bacteria present in the lungs were intimately associated with the epithelium of the alveoli or the cilia of the terminal bronchioli, as observed by light and electron microscopy. At 90 and 180 min postinoculation multiple focal early inflammatory lesions in which histologically different, more or less concentric zones could be distinguished were observed. In the center of these pneumonic areas bacteria were associated with infiltrated cells and exudate. In the zone surrounding the center, approximately 95% of the bacteria were lying with their longest side in close apposition to the epithelial cells of alveoli and the cilia of the terminal bronchioli. Bacteria were only sporadically associated with the cilia or the epithelium of the bronchi and trachea. Bacteria were not observed in tonsils or conchae. In view of the findings presented here, we propose the hypothesis that adherence of the A. pleuropneumoniae serotype 2 strain to epithelial cells of the lower respiratory tract constitutes an important initial step in pathogenesis.

Actinobacillus pleuropneumoniae↗
PubMed1994

Evaluation of five immunoassays for detection of Chlamydia psittaci in cloacal and conjunctival specimens from turkeys.

Five commercially available immunoassays were evaluated for the detection of Chlamydia psittaci in cloacal and conjunctival swabs from industrially raised turkeys: IMAGEN (DAKO Diagnostics, Ely, Cambridgeshire, United Kingdom), Chlamydia CEL-VET IF (Cellabs, Brookvale, Australia), IDEIA (DAKO Diagnostics), CELISA (Cellabs), and CLEARVIEW (Unipath, Bedford, United Kingdom). Results were compared with isolation in Buffalo Green Monkey cells as a reference method. For the conjunctival samples, the sensitivities of the IMAGEN test, the Chlamydia CEL-VET IF test, the IDEIA, the CELISA, and the CLEARVIEW test were found to be 100, 66, 0, 0, and 0%, respectively, as compared to the reference test. Also for the conjunctival samples, the specificities of the IMAGEN test, the Chlamydia CEL-VET IF test, and the IDEIA were found to be 100, 11, and 92.8%, respectively. For the cloacal specimens, the sensitivities of the IMAGEN test, the Chlamydia CEL-VET IF test, the IDEIA, the CELISA, and the CLEARVIEW test were found to be 100, 93.3, 26.6, 0, and 53.3%, respectively. Also for the cloacal specimens, the specificities of the IMAGEN test, the Chlamydia CEL-VET IF test, the IDEIA, and the CLEARVIEW test were found to be 92, 12, 100, and 88%, respectively. The IMAGEN test was the most sensitive and specific direct chlamydia antigen detection test for cloacal and conjunctival samples from turkeys.

Animals↗
PubMed1993

Primary pathogenicity of an European isolate of Chlamydia psittaci from turkey poults.

Chlamydia psittaci was isolated as the sole pathogenic agent from a severe outbreak of respiratory disease in a commercial broiler turkey farm in the Netherlands. The mortality rate in the flocks was 65%. Clinical signs included conjunctivitis, swelling of the sinus infraorbitalis and sneezing. Cloacal excretion of chlamydia was demonstrated in twelve out of fifteen birds examined by a direct immunofluorescence test. In all the fifteen birds antibodies against Chlamydia psittaci were detected in the sera by a competitive ELISA. At necropsy sinusitis, rhinitis, airsacculitis, pneumonia, pericarditis and enlargement of the liver and spleen were found. Chlamydiae were demonstrated in the sinus material of all and in conjunctival smears of eight of the fifteen examined birds. Chlamydiae were isolated from all the examined birds after one to three passages on Buffalo Green Monkey (BGM) cell cultures using samples taken from lung, liver and spleen. No other pathogens were isolated. The chlamydia isolate was typed using a panel of serovar-specific monoclonal antibodies in a micro-immunofluorescence test. The isolate belonged to the avian Chlamydia psittaci serovar D. Experimental inoculation with this isolate of 7-day-old specific pathogen free (SPF) turkeys resulted in severe clinical signs, with mortality and extensive pathological lesions, similar to those seen in turkeys from the examined broiler turkey farm. From the data it was concluded that this Chlamydia psittaci isolate can cause severe disease in turkeys.

Animals↗
PubMed1993

Actinobacillus pleuropneumoniae RTX-toxins: uniform designation of haemolysins, cytolysins, pleurotoxin and their genes.

The three different pore-forming RTX-toxins of Actinobacillus pleuropneumoniae are reviewed, and new and uniform designations for these toxins and their genes are proposed. The designation ApxI (for Actinobacillus pleuropneumoniae RTX-toxin I) is proposed for the RTX-toxin produced by the reference strains for serotypes 1, 5a, 5b, 9, 10 and 11, which was previously named haemolysin I (HlyI) or cytolysin I (ClyI). This protein is strongly haemolytic and shows strong cytotoxic activity towards pig alveolar macrophages and neutrophils; it has an apparent molecular mass in the range 105 to 110 kDa. The genes of the apxI operon will have the designations apxIC, apxIA, apxIB, and apxID for the activator, the structural gene and the two secretion genes respectively. The designation ApxII is proposed for the RTX-toxin which is produced by all serotype reference strains except serotype 10 and which was previously named App, HlyII, ClyII or Cyt. This protein is weakly haemolytic and moderately cytotoxic and has an apparent molecular mass between 103 and 105 kDa. The genes of the apxII operon will have the designations apxIIC for the activator gene and apxIIA for the structural toxin gene. In the apxII operon, no genes for secretion proteins have been found. Secretion of ApxII seems to occur via the products of the secretion genes apxIB and apxID of the apxI operon. The designation ApxIII is proposed for the nonhaemolytic RTX-toxin of the reference strains for serotypes 2, 3, 4, 6 and 8, which was previously named cytolysin III (ClyIII), pleurotoxin (Ptx), or macrophage toxin (Mat).(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus pleuropneumoniae↗
PubMed1993

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↗
PubMed1993

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↗