Analysis of Haemophilus influenzae infections after vaccination reported.

2004 MAY 5 - (NewsRx.com & NewsRx.net) -- Scientists report results of an analysis of invasive Haemophilus influenzae infections after extensive vaccination against H. influenzae type b in a recent issue of the Journal of Clinical Microbiology.

"Little clinical and microbiological information is available about invasive Haemophilus influenzae infection after widespread vaccination against H. influenzae type b (Hib). We conducted an active community surveillance study on invasive H. influenzae during a 2-year period in a community of more than 5 million people after vaccination against Hib in children was introduced," researchers in Spain report.

"The median incidence was 16.3 cases/100,000 persons per year in children less than 1 year old and 4.41 cases/100,000 persons in children less than

"Ampicillin and cotrimoxazole resistance occurred at frequencies of 24.2 and 48.4%, respectively," reported Campos and his associates. "Antibiotic resistance was more prevalent in capsulated than in noncapsulated H. influenzae. Invasive isolates were highly resistant to antibiotics that were used infrequently in the community. Nontypeable H. influenzae were genetically much more heterogeneous than capsulated strains. Capsule-deficient mutants (b-) were not detected. Plasmid carriage was linked to antibiotic resistance and capsulated strains. Over the study period, the incidence of invasive H. influenzae infections, either encapsulated or not, did not increase."

The investigators concluded, "In the post-Hib vaccination era, most invasive infections were due to noncapsulated strains and ...