Phase-variable expression of the 145-kDa surface protein of Brazilian purpuric fever case-clone strains of Haemophilus influenzae biogroup aegyptius.

Abstract

Clonally related strains of Haemophilus influenzae biogroup aegyptius have recently been associated with Brazilian purpuric fever (BPF). Antibodies to a 145-kDa minor outer membrane protein (P145) are bactericidal and protect against experimental bacteremia. To determine if P145 is conserved among case-clone strains, case-clone strains were screened for P145 expression. Assays of a large number of colonies of each strain using colony immunoblot revealed colonies reactive with anti-P145 sera in all 17 case-clone strains. P145 was expressed at a low frequency (0.08%-2.2% of colonies) in 14 strains and at a high frequency (> 98%) in 3 strains. Expression of P145 by reactive colonies was confirmed by SDS-PAGE. Also, anti-P145-nonreactive variant colonies of P145-expressing strains were detected in 0.4%-1.5% of colonies. These findings indicate P145 is conserved among BPF case-clone strains and is subject to phase-variable expression.

• Authors: L G Rubin
• Journal: The Journal of infectious diseases (J Infect Dis) Vol. 171 Issue 3 Pg. 713-7 (Mar 1995) ISSN: 0022-1899 [Print] United States
• PMID: 7876625 (Publication Type: Journal Article)

Chemical References

• Bacterial Outer Membrane Proteins

Topics

• Animals
• Bacteremia (microbiology)
• Bacterial Outer Membrane Proteins (analysis)
• Brazil
• Fever (microbiology)
• Haemophilus influenzae (chemistry)
• Humans
• Molecular Weight
• Rats