Characterization of haemophilus influenzae isolated from invasive disease in Brazil from 1990 to 1999.
The Haemophilus influenzae serotype b (Hib) conjugate vaccine was introduced in the National Immunization Program in Brazil in the second half of 1999. A retrospective analysis on serotypes, biotypes, and antimicrobial resistance of Hi invasive strains obtained through Hi survey was conducted to document the characteristics of this pathogenic agent during a decade prior the use of Hib vaccine. A total 3,204 strains from 1990 to 1999 were studied, being 88.2% isolated from cerebrospinal fluid, 10.7% from blood, and 1.1% from pleural fluid. The rate of 90.9% of strains was obtained from children up to 4 years old, and the age group >6 months old to 1 year was the higher risk to Hi infection. Type b was, by far, the most common type (97.8%), followed in frequency by type a (0.5%); only 1.5% was a nontypable strain. Biotypes I and II accounted for 97.8% of isolates. Resistance to ampicillin (AM) and chloramphenicol (CO) was detected at rates of 18.1% and 19.1%, respectively, whereas simultaneous resistance to AM and CO was identified in 13.9% of strains. Total concordance was found between AM resistance and beta-lactamase production. No strain showed resistance to ceftriaxone and rifampicin. In conclusion, the data generated through this laboratory-based surveillance should serve as a reference for assessing the impact of Hib vaccination and to detect changes on the pattern of Hi diseases in the country.
Zanella
Rosemeire C
RC
Instituto Adolfo Lutz, Bacteriology Department, São Paulo, SP, Brazil. cobo@ial.sp.gov.br
Casagrande
Silvana T
ST
Bokermann
Sérgio
S
Almeida
Samanta C G
SC
Brandileone
Maria Cristina C
MC
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001431:Bacteriological Techniques; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004352:Drug Resistance, Microbial; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology*; D018073:Haemophilus Vaccines / Q000627:therapeutic use; D019741:Haemophilus influenzae type b / Q000187:drug effects*; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012189:Retrospective Studies; D012703:Serotyping; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D018073:Haemophilus Vaccines; D018074:Vaccines, Conjugate