Comparaison de l'activité de la pipéracilline associée au tazobactam, au sulbactam ou à l'acide clavulanique, sur 70 souches de Haemophilus influenzae produisant une β-lactamase

[Study of Haemophilus influenzae strains isolated at the Tunis children's hospital in the prevaccination era (1999-2002)]

OBJECTIVE

This study had for aim to define the pattern of Haemophilus influenzae infections in a Tunisian hospital during the prevaccination era. We determined serotypes, biotypes, and antibiotic susceptibility of H. influenzae strains.

DESIGN

187 H. influenzae strains were identified in various samples between 1999 and 2002.

RESULTS

Strains were isolated essentially from respiratory samples in 63.7% and cerebrospinal fluid in 21.4 %. The mean age of children with invasive infections was 16 months. All invasive strains belong to serotype b. Biotypes I, II and III were the most frequent (84.7%). Ampicillin resistance with betalactamase producing mechanism occurred in 26,7% of isolates, this type of resistance was more frequent among invasive strains (37.2%) than in non-invasive ones (22.8%). All betalactamase producing strains had amoxicillin MICs above 1 mg/l, these strains were susceptible to amoxicillin+clavulanate. Three strains were betalactamase negative ampicillin resistant with ampicillin MICs: 1.5, 3, and 4 mg/l. All strains were susceptible to cefotaxim with MICs < 0.19 mg/l. Antibiotic resistance concerned: chloramphenicol: 7.5%, tetracycline: 6.9% and trimethoprime-sulfamethoxazole: 13.9%. 8.1% of the strains were kanamicin resistant but concerned only betalactamase producing strains.

CONCLUSION

Before the introduction of a conjugate vaccine, all invasive infections in young children were caused by H. influenzae b strains.