Genetic analysis of a plasmid encoding haemocin production in Haemophilus paragallinarum.
The full sequence of plasmid p250, isolated from Haemophilus paragallinarum strain HP250, has been obtained. The plasmid contains seven ORFs: a putative integrase, a putative replication protein (repB) and five ORFs similar to those from the haemocin (bacteriocin) hmcDCBAI operon from Haemophilus influenzae. Of 19 other non-plasmid-containing H. paragallinarum strains screened (11 serovar reference strains and 8 field isolates), 17 strains produced haemocin and were resistant to killing by strain HP250. These strains, unlike strain HP250, have a chromosomally encoded haemocin operon. A number of other members of the family Pasteurellaceae were tested for haemocin sensitivity. Pasteurella avium, Pasteurella volantium and Pasteurella species A, all non-pathogenic bacteria found in the respiratory tract of chickens suffering from respiratory diseases, were sensitive to H. paragallinarum haemocin. However, amongst the pathogenic Pasteurellaceae, 50 % of P. multocida isolates and all five isolates of Pasteurella haemolytica tested were sensitive to the haemocin. Given the prevalence of haemocin production in H. paragallinarum strains, it may play a role in aiding colonization by inhibiting other Gram-negative bacteria that are associated with the respiratory tract in chickens. The origin of replication from plasmid p250 has been used to generate an Escherichia coli-H. paragallinarum shuttle vector which may be useful in genetically manipulating H. paragallinarum.
Terry
Tamsin D
TD
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Zalucki
Yaramah M
YM
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Walsh
Shannon L
SL
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Blackall
P J
PJ
Agency for Food and Fibre Sciences, Animal Research Institute, Department of Primary Industries, Yeerongpilly, Australia.
Jennings
Michael P
MP
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
D000818:Animals; D001430:Bacteriocins / Q000235:genetics*; D001483:Base Sequence; D002645:Chickens; D017931:DNA Primers; D005822:Genetic Vectors; D044134:Haemophilus paragallinarum / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping
D001430:Bacteriocins; D017931:DNA Primers; C030520:haemocin