Staphylococcal tenosynovitis and osteomyelitis are world-wide problems of broilers and broiler breeders caused by staphylococci. Pathogenesis of the disease is ill defined. Avian heterophils are analogous to mammalian neutrophils but the granules appear to be different. The first chemotactic study was done on heterophils from chickens having natural staphylococcal infection brought from a commercial broiler flock and on the heterophils obtained from healthy 6-8 weeks old chickens brought from a local hatchery as one day old chicks. In the second study, a chemotactic study was done with three different staphylococci on heterophils obtained from healthy 6-8 weeks old chickens brought from a local hatchery as one day old chicks. Results for the first study showed a decreased chemotactic response in the heterophils of chickens naturally infected with staphylococcus compared to healthy chicken heterophils in response to minimum essential medium, pooled normal chicken serum and E. coli endotoxin with normal chicken serum used as chemoattractants. Second study results showed that pathogenic capsule type 5 and type 8 Staphylococcus aureus isolates both induced chemotaxis in heterophils from healthy chickens to a significantly greater degree than did a non-pathogenic Staphylococcus xylosus. The Staphylococcus aureus isolate with capsule type 5 induced heterophil chemotaxis more than the capsule type 8 isolate. / Graduation date: 1993

published_or_final_version / Zoology / Master / Master of Philosophy

Salmonella enteritidis (S. enteritidis) is a bacterial pathogen of chickens, and is currently one of the leading causes of human food poisoning in the world. It is believed that contaminated poultry products, especially eggs and egg products, have been responsible for the dramatic increase in the incidence of this Salmonella serotype. Detection of S. entertidis has conventionally involved bacteriological examination of samples, yet these procedures are time-consuming which could lead to the rapid spread of S. enteritidis through commercial flocks and potentially cause a human health risk. A number of alternative detection techniques, mostly based on serological methods, have been reported as effective diagnostic assays. However, some of these reports have not been supported by representations of SDS-PAGE gels or Western blots. The objective of this study was the evaluation of these serological techniques as well as a PCR amplification technique, which has been reported to show promising results as a diagnostic method. The techniques discussed in these reports were evaluated with regards to how rapid they were, their specificity and their potential for use in local diagnostic laboratories. Antigens from the outer surface of S. enteritidis were purified by several methods and their antigenicity was tested by separating the antigens by means of SDS-PAGE, followed by Western blotting using sera of chickens infected with S. enteritidis. A high degree of cross reactivity was observed with many of the antigens tested, especially the lipopolysaccharides (LPSs) and outer membrane proteins (OMPs) which had previously been reported as containing antigens which could be used for specific detection of S. enteritidis. This cross-reactivity could be explained by the conserved nature of many of the LPS and OMP antigens among the Salmonella serotypes tested. A fimbrial antigen, SEF14, which has been reported as a novel antigen, was seen as a prominent band at 14.3 kDa and was found to react with antibodies against S. enteritidis, yet not to the specificity levels described in previous reports. PCR amplification of the sefA gene sequence, which encodes for the SEF14 fimbrial antigen, was found to give a predicted product of 310 bp when using a previously described oligonucleotide primer pair. This amplified product was found to be specific for S. enteritidis and other serogroup D Salmonella serotypes that are not poultry pathogens The cross-reactivity observed with many of the serological techniques used in this study, meant that detection of S. enteritidis infection in chickens was considerably hindered. However, the identification of further novel antigens by serological means, could result in the development of new vaccines. The specificity and speed afforded by PCR amplification indicated that this technique showed excellent potential for use in local diagnostic laboratories. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.