1982 Volume 56 Issue 4 Pages 286-293
Chloramphenicol-resistant or both ampicillin- and chloramphenicol-resistant strains of Haemophilus influenzae has rarely been isolated. We have found five chloramphenicol-resistant H. influenzae in 1979 and five strains in 1980. The source and incidence of H. influenzae strains were as follows: from washed sputum, 8; nasopharynx, 1; cerebrospinal fluid, 1: Furthermore, four strains of both ampicillin- and chloramphenicolresistant H. influenzae were isolated from clinical specimen (washed sputum, 2; nasopharynx, 1; otorrhea, 1) in 1980.
Minimum inhibitory concentrations were determined by agar dilution method with inoculation of 106/ml.
Chloramphenicol-resistant strains were found to have MICs of more than 6.25μ/ml. In order to clarify whether these strains produce chloramphenicol acetyltransferase (CATase) or not, we examined by the method described by Manten (1976).
All these chloramphenicol-resistant and both ampicillin- and chloramphenicol-resistant strains were proved to produce CATase.
Four strains of both ampicillin- and chloramphenicol-resistant H. influenzae showed beta-lactamase positive.
Considering the emergence of both ampicillin- and chloramphenicol-resistant strains, recommendation of Committee on Infectious Diseases stating that the initial therapy for serious infections due to H. influenzae has become insufficient.
We should be alert to antimicrobial resistance of H. influenzae, and alternative forms of treatment should be studied.
