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.
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Tamsin D
TD
Terry
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Yaramah M
YM
Zalucki
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Shannon L
SL
Walsh
Agency for Food and Fibre Sciences, Animal Research Institute, Department of Primary Industries, Yeerongpilly, Australia.
P J
PJ
Blackall
Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
Michael P
MP
Jennings
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