Antibiotic resistance in Pseudomonas aeruginosa from infections of the ear, nose and throat.

1,000 strains of Ps. aeruginosa isolated from disease conditions of the ear, nose and throat, were examined for sensitivity to 9 antibiotics. Only 4.5 % of them were sensitive to all 9. The low incidence of strains resistant to polymixin B, colistin and carbenicillin makes them most suitable for the treatment of infections due to this organism, though the need for parenteral administration limits their systemic use to in-patients. A high level of cross-resistance exists between polymixin B and colistin, while there are various degrees of cross-resistance between the aminoglycoside antibiotics streptomycin, framycetin and neomycin. 63.9 % of strains resistant to oxytetracycline are cross-resistant to the chemically-unrelated chloramphenicol.