Drug Susceptibility Studies Research Articles

COMMITTEE OF THE SECTION ON DISEASES OF THE CHEST

THE FACT has been established that children may acquire a primary tuberculosis infection with tubercle bacilli resistant to streptomycin. The source of the infection can often be traced to an adult previously treated with streptomycin from whom drug-resistant organisms can be cultured. Relatively little information about primary infections in children with bacilli showing drug resistance to isoniazid is available, and no reports have been published from the United States. The Committee therefore decided it was of importance to determine if possible the incidence of such infections. Most of the 57 members of the Section on Diseases of the Chest are actively engaged in care of tuberculous children. A questionnaire was distributed to them in the spring of 1958 in an attempt to learn the incidence of initial infection with drug-resistant tubercle bacilli. Replies were received from everyone, but 20 individuals had little or no information to give. Thirty-seven members of the Section furnished information from 34 clinics. The present report is based on the data supplied from 31 clinics in which cultures of gastric lavages were done regularly prior to treatment. Only 7 of these 31 clinics did drug-susceptibility studies on positive cultures routinely; 21 clinics reported that susceptibility studies were not done regularly, and 3 reported that drug susceptibility of cultures of tubercle bacilli was never tested. It was possible to estimate that the seven clinics which did drug-susceptibility tests routinely had reported on a total group of about 2,500 tuberculous children, of whom about 1,800 had been under observation since the introduction of isoniazid into drug regimens. Only 4 of the 7 clinics which did drug-susceptibility tests routinely reported the finding of initial (pretreatment) drug-resistant cultures of tubercle bacilli. Only 2 of the 3 clinics reporting bacterial resistance to isoniazid did catalase tests routinely. The method of expressing bacterial resistance varied in each clinic. In the present report we have considered that bacterial resistance to isoniazid was present if 1% of the total population grew in 0.2µg/ml, and bacterial resistance to streptomycin if 1% of the total population grew in 2.0µg/ml.