[In vitro sensitivity to antimicrobial agents of Haemophilus influenzae strains isolated from clinical specimens]

In-vitro activity of several antimicrobial agents were evaluated against Haemophilus influenzae (n:127) isolated from clinical specimens within the years 2000 and 2002 in a children's hospital. Antimicrobial susceptibility tests were performed by disk diffusion method according to the recommendations of the NCCLS standards and beta-lactamase activity was investigated by nitrocefin test. Resistance rates for the antibiotics were as follows: ampicillin 5.6%, trimethoprim-sulfamethoxazole (TMP/SMX) 27.5%, tetracycline 8.6%, clarithromycin 7%, chloramphenicol 4.7%. Five isolates (3.9%) were found multiple resistant. Beta-lactamase activities were detected in all of the ampicillin resistant isolates. None of the isolates were resistant to ampicillin-sulbactam, cefaclor, cefuroxime, cefprozil, cefpodoksim, cefotaxime, meropenem or ciprofloxacin. According to these results, resistance to ampicillin is low in our H. influenzae isolates compared to other European countries but resistance to TMP/SMX is very high and this finding has to be taken into account in the empirical therapy of community acquired respiratory tract infections.