Salmonella--serotypes and drug resistance (1966-1970)

Abstract

Recently, salmonella infection has become recognized as an important public health problem in Japan. Patients with dysentery-like symptoms without shigellae are apparently increasing in number, and thereby causatives are frequently salmonellae.In order to get epidemiological details on salmonella contamination in Osaka prefecture, we performed isolations of salmonellae from human feces as well as non-human materials including various kind of meat (beef, pork, chicken and minced meat), water of sewages and other materials. Isolated salmonellae were examined for serotypes and drugresistance.The results were summarized as follows:1) The isolation rate of salmonellae from human feces had steadily increased during the period be-tmeen 1966 and 1970, the percentage being from 0.09 to 0.84.2) The high incidence was seen in the case of meat and other non-human materials. We have found, incidentally, that for the isolation plate from meat generally available in the city market, MLCB plate is superior to SS plate and in the case of using Hajna's tetrathionate broth, better results were obtainable in 48 hours incubation than 24 hours incubation.3) Out of isolated strains, 79.8% were found to be resistant (25.0mcg/ml or over) to either one of streptomycin (SM), chloramphenicol (CP) or Tetracycline (TC). Particularly, 70.6% were resistant to SM. The isolation rate of resistant strains to CP or TC was higher in non-human materials (3.4% to CP and 35.0% to TC) than in human materials (0.9% to CP and 11.0% to TC).4) As for the resistance pattern to antibiotics, we found that two peaks were seen at the concentration 25.0mcg/ml and 100mcg/ml in the distribution of resistance valud of the strains to SM except S. enteritidis which showed only one peak at 1.56mcg/ml and any strains of which never exceeded the level 25.0mcg/ml.As a further study we investigated 20 more strains of S. enteritidis including those spared from Osaka Municipal Momoyama Hospital by the courtesy of Dr Sugiyama and those from meat and other materials isolated by us in 1971. The results were the same.To CP and TC, only one peak was demonstrated at 6.25 mcg/ml and 3.125 mcg/ml, respectively.5) It was experienced in this series that two different phage types of S. paratyphi B (Beccles 3a and 3a Ivar. 4) were isolated from the same carrier, but the resistant pattern of them proved the same.