Drug resistance of Shigella and Salmonella and the inhibition and elimination of drug resistance

이질균(痢疾菌) 및 살모내라의 약제내성(藥劑耐性), 내성화방지(耐性化防止) 및 제거(除去)

Ninety-five strains of Shigella, 70 of Salmonella paratyphi A, and 230 of Salmonella typhi were tested for their resistance to drugs. Also studied was the inhibition and elimination of drug resistance. All except one strain of Shigella consisted of 79 Sh. flexneri and 16 Sh. sonnei were multiply resistant to chloramphenicol, tetracycline, streptomycin, and splfisomidine. Among them, 70 strains were resistant to ampicillin and carbenicillin, 80 to trimethoprim-sulfamethoxazole, 22 to nalidixic acid, and one to kanamycin, but strain resistant to gentamicin, cephaloridine, and rifampin was not encountered. All strains of S. paratyphi A and S. typhi were susceptible to drugs tested, except sulfisomidine and rifampin, for which all S. paratyphi A were slightly resistant to sulfisomidine and the majority of S. paratyphi A and S. typhi were slightly resistant to rifampin. Approximately 80% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation, and the resistance was considered to be mediated by R plasmids. The frequency of transfer of drug resistance varied by donor strains and recipients, but not by selecting drugs. Resistance to nalidixic acid was not transferred by conjugation to the recipients. Drug-resistant Shigella strains successively subcultured in nutrient agar stabs contained clones resistant to drugs and those susceptible to drugs, but the ratio of resistant and susceptible clones varied by strains. The multiply drug-resistant S. typhi and Shigella strains were found to not lose completely their drug resistance by subculture in media. Acriflavine has some effect on the elimination of drug resistance mediated by R plasmids, but the effect varied markedly by strains. Atabrine has no effect among strains tested. The combination of drugs increased the drug actions in majority of cases with synergistic or additive effects.

1978년(年)에 분리(分離)한 9주(株)의 Shigella, 70주(株)의 Salmonella paratyphi A 및 230주(株)의 S. typhi의 약제내성(藥劑耐性), 내성화방지(耐性化防止) 및 제거(除去)에 대(對)하여 실험(實驗)하여 다음과 같은 성적(成績)을 얻었다. Shigella는 79주(株)가 Sh. flexneri, 16주(株)가 Sh. sonnei였는데 1주(株)를 제외(除外)한 94주(株)가 chloramphenicol tetracycline, streptomycin, sulfisomidine에 다약제내성(多藥劑耐性)이었으며 그중(中) 70주(株)는 ampicillin과 carbenicillin에, 80주(株)는 trimethoprim-sulfamethoxazole에, 22주(株)는 nalidixic acid에, 1주(株)는kanamycin에도 내성(耐性)이었다. Gentamicin, amikacin, cephaloridine, rifampin에 내성(耐性)인 균주(菌株)를 없었다. S. paratyphi A와 S. typhi는 공시약제(供試藥劑)에 감수성(感受性)이었으나 다만 rifampin, 또는 sulfisomidine에 약(弱)한 내성(耐性)을 가진 것이 있었다. 다약제내성(多藥劑耐性)인 shigella의 약(約) 80%가 전달성(傳達性) R plasmid를 가지고 있어서 그 내성(耐性)을 E. coli에 전달(傳達)시킬 수 있었다. 내성전달빈도(耐性傳達頻度)는 공시균주(供試菌株) 및 피전달균(被傳達菌)에 따라 차이(差異)가 있었다. 보존(保存)한 내성균주(耐性菌株)는 그 비율(比率)은 균주(菌株)에 따라 차이(差異)가 있으나 내성균(耐性菌)과 감수성균(感受性菌)으로 구성(構成)되어 있었으며 계대배양(繼代培養)에 의하여 내성(耐性)이 쉽게 탈락(脫落)되지는 안하였다. Acriflavine은 내성(耐性)을 탈락(脫落)시키는 효과(效果)는 있었으며 균주(菌株)에 따라 그 차이(差異)가 심(甚)하였고 atabrine은 효과(效果)가 없었다. 약제(藥劑)의 병용(倂用)은 Shigella에 대(對)한 작용(作用)을 증강(增强)시키는 경우(境遇)가 많으며 대체(大體)로 상승작용(相乘作用)을 나타냈고 상가작용(相加作用)을 나타내는 경우(境遇)가 있었으나 길항작용(拮抗作用)은 볼 수 없었다.