Freddy Haesebrouck | Ghent University (original) (raw)

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Papers by Freddy Haesebrouck

BMC Veterinary Research, 2014

Clostridium perfringens type A has been shown to be the causative agent of a wide variety of ente... more Clostridium perfringens type A has been shown to be the causative agent of a wide variety of enteric diseases in humans and animals, including bovine enterotoxemia. Enterotoxemia is a sudden death syndrome with necro hemorrhagic lesions in the small intestine, which mainly affects suckling calves and veal calves [1]. Predominantly veal calves of beef cattle breeds are affected, and losses due to enterotoxemia may be responsible for up to 20% of total mortality [2, 3]. Recently, alpha toxin has been proposed as an essential factor for induction of enterotoxemia in veal calves, which introduces the possibility to use it as a vaccine [4]. The use of only the main toxin instead of the whole arsenal of extracellular toxins and enzymes eliminates irrelevant or even immunosuppressive components and therefore may induce a stronger, protective immune response. In this study, we have compared a commercial multivalent vaccine with native alpha toxin, formalin inactivated alpha toxin and recomb...

Journal of Applied Microbiology, 2004

Veterinary microbiology, Jan 12, 2009

In this study, the accuracy of two phenotypic tests, API Staph ID 32 and Staph-Zym, was determine... more In this study, the accuracy of two phenotypic tests, API Staph ID 32 and Staph-Zym, was determined for identification of coagulase-negative staphylococci (CNS) from bovine milk samples in comparison with identification based on DNA-sequencing. A total of 172 CNS isolated from bovine milk were classified into 17 species. The most frequently isolated species based on rpoB sequencing were Staphylococcus chromogenes and Staphylococcus epidermidis, followed by Staphylococcus xylosus, Staphylococcus warneri and Staphylococcus equorum (37, 13, 9, 8 and 6% of isolates, respectively). The API Staph ID 32 correctly identified 41% of the CNS isolates. Best agreement with rpoB sequence based species identification was found for S. epidermidis, Staphylococcus hyicus and S. xylosus (100, 89 and 87%, respectively). The positive predictive value was 89, 100 and 52%, respectively. Poor sensitivity was observed for 3 of the 5 most frequently found species, S. chromogenes (37%), Staphylococcus warneri...

Veterinary Microbiology, 2008

Veterinary Research, 2012

Although aspergillosis is one of the most common diseases in captive birds, the pathogenesis of a... more Although aspergillosis is one of the most common diseases in captive birds, the pathogenesis of avian aspergillosis is poorly known. We studied the role of avian respiratory macrophages as a first line of defense against avian aspergillosis. The phagocytic and killing capacities of avian respiratory macrophages were evaluated using pigeon respiratory macrophages that were inoculated with Aspergillus fumigatus conidia. On average, 25% of macrophage-associated conidia were phagocytosed after one hour. Sixteen percents of these cell-associated conidia were killed after 4 h and conidial germination was inhibited in more than 95% of the conidia. A. fumigatus conidia were shown to be cytotoxic to the macrophages. Intracellularly germinating conidia were located free in the cytoplasm of necrotic cells, as shown using transmission electron microscopy. These results suggest that avian respiratory macrophages may prevent early establishment of infection, unless the number of A. fumigatus conidia exceeds the macrophage killing capacity, leading to intracellular germination and colonization of the respiratory tract.

Veterinary Microbiology, 2003

The ability of Salmonella enterica serotype Enteritidis isolates to adhere to immobilized secreti... more The ability of Salmonella enterica serotype Enteritidis isolates to adhere to immobilized secretions of the isthmus of the laying hen was determined in an ELISA-type assay. One-third of the 56 isolates tested in the logarithmic growth phase, adhered to the isthmal secretions. Using a binding assay of the isolates to thin paraffin sections of the oviduct, we demonstrated that the receptor of the adhesion was localized inside the tubular gland cells of the isthmus. The adhesion to immobilized isthmal secretions as well as to the paraffin sections was blocked by the addition of mannose. A fimD mutant of S. Enteritidis, lacking type 1 fimbriae, did not adhere, confirming that the adhesion was mediated by type 1 fimbriae. Mannosylated glycoproteins were demonstrated in the isthmus glandular cells using confocal laser scanning microscopy by FITC-labelled Lens culinaris lectins. It is hypothesized that the binding of S. Enteritidis to isthmal secretions could play a role in the contamination of eggs through incorporation of the bacteria in the shell membranes.