title: Plasmid-encoded NAD independence in some South African isolates of Haemophilus paragallinarum.
abstract: Atypical Haemophilus paragallinarum have been isolated from both laying hens and broilers suffering from typical symptoms of infectious coryza in South Africa. Re-inoculation of these bacteria into SPF chickens resulted in similar pathology. The bacteria could be successfully re-isolated from the experimentally infected chickens. Four of the isolates from layers and 3 of those from broilers were found to be closely related to H. paragallinarum serotype A (0083 strain) when tested by the use of a panel of locally developed monoclonal antibodies in the enzyme linked immunosorbent assay (ELISA). A total of 15 isolates from layers and 19 from broilers were found to be more typical of previously collected South African field isolates of H. paragallinarum. A 3rd group, consisting of 5 isolates from layers and 15 from broilers, showed no reaction with the panel of monoclonal antibodies. All the isolates were regarded as atypical because they no longer required V factor (NAD) for growth, whereas strain 0083 and previously collected field isolates M 85 and SB 86 did require it. Crude plasmid extractions from an isolate serologically related to 0083 was used to convert reference strains of H. paragallinarum into NAD-independent isolates, thus indicating that NAD independence is carried on a plasmid.
authors.affiliation: Department of Poultry Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
authors.forename: R R
authors.initials: RR
authors.lastname: Bragg
authors.forename: L
authors.initials: L
authors.lastname: Coetzee
authors.forename: J A
authors.initials: JA
authors.lastname: Verschoor
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002645:Chickens / Q000382:microbiology*; D006190:Haemophilus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006192:Haemophilus Infections / Q000382:microbiology / Q000662:veterinary*; D009243:NAD / Q000378:metabolism*; D010957:Plasmids; D011201:Poultry Diseases / Q000382:microbiology*; D014169:Transformation, Bacterial
chemical_list: D000911:Antibodies, Monoclonal; D009243:NAD