Open AccessThe Effect of Serum-factor Induced Resistance to Somatic Antibodies on the Virulence of Haemophilus influenzae Type b
Author(s) -
Rubin Lg,
E. Richard Moxon
Publication year - 1985
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-131-3-515
Subject(s) - virulence , microbiology and biotechnology , haemophilus influenzae , biology , antibody , pathogenesis , phenotype , virulence factor , immunity , haemophilus , inoculation , bacteria , immunology , immune system , antibiotics , gene , genetics
Studies on the pathogenesis of Haemophilus influenzae b infection have used bacteria grown in vitro which are relatively serum-sensitive (using serum devoid of anticapsular antibody) compared to organisms taken from infected hosts. We compared the virulence of relatively serum-sensitive and serum-factor induced serum-resistant H. influenzae b by inoculating rats with organisms having one or the other phenotype. The serum-resistant phenotype was more virulent following intraperitoneal or intravenous inoculation; however, there was no difference in the incidence of colonization or bacteraemia following intranasal inoculation. Furthermore, organisms colonizing the pharynx of rats had the serum-resistant phenotype. Thus, different phenotypes of the same strain of H. influenzae b differed in virulence following parenteral, but not intranasal, inoculation of bacteria. This could be explained by a change from serum-sensitive to serum-resistant phenotype shortly after entering the nasopharynx. The phenotype of micro-organisms grown in vitro may differ from organisms in infected individuals and these differences may be of critical importance in studies of immunity to infection and the pathogenesis of infection.