H. influenzae is a fastidious bacteria, so the selection of a reliable method for in-vitro susceptibility tests is particularly important. The E-test is a practical method for detecting in-vitro antimicrobial susceptibility of antibiotics by MIC values. This study was performed using the E-test for direct patient management and in order to obtain epidemiological data on H. influenzae. The detection of antimicrobial agent resistance among fifty-seven H. influenzae isolates from lower respiratory tract infections in childhood was studied by the E-test. The E-test was performed on HTM agar according to the instruction manual recommendations. The susceptibility ratios and the MIC90 values of the isolates for ampicillin, cefaclor, cefotaxime, chloramphenicol, ciprofloxacin and imipenem were 89 % and 1.5µg/ml, 98.2 % and 6µg/ml, 100 % and 0.047µg/ml, 98.2 % and 1.5µg/ml, 100 % and 0.075µg/ml, and 100% and 1.0µg/ml respectively. All of the antibiotics tested were found to be effective against H. influenzae.

H. influenzae is a fastidious bacteria, so the selection of a reliable method for in-vitro susceptibility tests is particularly important. The E-test is a practical method for detecting in-vitro antimicrobial susceptibility of antibiotics by MIC values. This study was performed using the E-test for direct patient management and in order to obtain epidemiological data on H. influenzae. The detection of antimicrobial agent resistance among fifty-seven H. influenzae isolates from lower respiratory tract infections in childhood was studied by the E-test. The E-test was performed on HTM agar according to the instruction manual recommendations. The susceptibility ratios and the MIC90 values of the isolates for ampicillin, cefaclor, cefotaxime, chloramphenicol, ciprofloxacin and imipenem were 89 % and 1.5µg/ml, 98.2 % and 6µg/ml, 100 % and 0.047µg/ml, 98.2 % and 1.5µg/ml, 100 % and 0.075µg/ml, and 100% and 1.0µg/ml respectively. All of the antibiotics tested were found to be effective against H. influenzae.