A Mass Incidence of Bacillary Dysentery Caused by Oxytetracycline Resistant Strain on an Educational Trip among boys of Asahigaoka High School in Nagoya

Abstract

A mass incidence of bacillary dysentery broke out in March, 1957 among 728 students and 29 teachers on an educational trip to Shikoku and Chugoku districts. Afterreturning to Nagoya, the feces of not only the students who travelled but also those who did not travel and their family members were examined for dysentery bacilli.
Of 54 positive cases 28 were diagnosed as bacillary dyentery and 26 as bacillary carriers. The isolated strains were serologically classified into Sh. flexneri 2a, 3a, 4a, var. Y and Sh. sonnei, the most numerous being Sh. flexneri 2a, i. e. 45 strains.
Fourty nine strains were examined for resistance against various antibiotics and sulfonamides. Out of 40 2a strains isolated from those travelling and regarded as causative agent of the mass incidence, 32 demonstrated 250 γ/cc resistance against oxytetracycline (Terramycin), 100 γ/cc against tetracycline, 50 γ/cc to aureomycin, 0.5 γ/cc against chloromycetin, 10 γ/cc to streptomycin and 100 mg/dl against sulfathiazol.
The clinical symptoms disappeared rapidly by the application of antibiotics, particularly chloromycetin. Out of 12 cases treated with terramycin, 11 reexcreted the bacilli in their feces after the medication, and out of 38 cases including carriers the reexcretion was detected after having left the hospital. The source of infection could not be discoverd.