PREVALENCE AND DISTRIBUTION OF THE HMW AND HIA GENES AND THE HMW AND HIA ADHESINS AMONG GENETICALLY DIVERSE STRAINS OF NONTYPABLE HAEMOPHILUS-INFLUENZAE
Jw. Stgeme et al., PREVALENCE AND DISTRIBUTION OF THE HMW AND HIA GENES AND THE HMW AND HIA ADHESINS AMONG GENETICALLY DIVERSE STRAINS OF NONTYPABLE HAEMOPHILUS-INFLUENZAE, Infection and immunity, 66(1), 1998, pp. 364-368
Nontypeable Haemophilus influenzae is a common cause of human disease
and initiates infection by colonizing the upper respiratory tract, In
previous work we identified high-molecular-weight adhesins referred to
as HMW1 and HMW2, expressed by nontypeable strain 12, and determined
that most strains of nontypeable H. influenzae express one or two anti
genically related proteins, More recently, we determined that some str
ains lack HMW1-and HMW2-like proteins and instead express an adhesin c
alled Hia. In the present study, we determined the prevalence and dist
ribution of the hmw and hia genes in a collection of 59 nontypeable st
rains previously characterized in terms of genetic relatedness, Based
on Southern analysis, 47 strains contained sequences homologous to the
hmw1 and hmw2 genes and nine strains contained homologs to hia. No st
rain harbored both hmw and hia, and three strains harbored neither, Al
though the hmw and hia genes failed to define distinct genetic divisio
ns, the hmw-deficient strains formed small clusters or lineages within
the larger population structure, Additional analysis established that
the IS1016 insertion element was uniformly absent from strains contai
ning hmw sequences but was present in two-thirds of the hmw-deficient
strains, As IS1016 is associated with the capsule locus (cap) in most
encapsulated strains of H. influenzae, we speculate that hmw-deficient
nontypeable strains evolved more recently from an encapsulated ancest
or.