Brazilian purpuric fever caused by Haemophilus influenzae biogroup aegyptius strains lacking the 3031 plasmid.
Brazilian purpuric fever (BPF) is a life-threatening pediatric infection caused by Haemophilus influenzae biogroup aegyptius (Hae), an organism formerly associated with only self-limited purulent conjunctivitis. Strains of Hae causing BPF have a 24-MDa plasmid with a specific AccI restriction pattern designated 3031. This plasmid was thought to code for a virulence factor because it had been detected only among Hae strains isolated from BPF cases or their contacts. From 3 typical BPF cases recently identified in São Paulo State, sterile-site Hae isolates were obtained; these isolates were similar to earlier BPF-associated Hae except they did not possess a 3031 plasmid. HindIII restricted chromosomal DNA from these strains was probed with purified 3031 plasmid DNA under high-stringency conditions. There was no evidence that 3031 plasmid DNA had become chromosomally integrated. It appears that the 3031 plasmid does not code for BPF-specific virulence factors.
Tondella
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ML
Division of Bacteriology, Adolfo Lutz Institute, São Paulo, Brazil.
Quinn
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FD
Perkins
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BA
D015139:Blotting, Southern; D002876:Chromosomes, Bacterial; D006192:Haemophilus Infections / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000235:genetics* / Q000472:pathogenicity; D006801:Humans; D010957:Plasmids; D011693:Purpura / Q000382:microbiology*; D014774:Virulence