[Isolation of group A streptococci from pharyngitis patients of all ages--studies from the clinical and epidemiological standpoint].

During the period from June 1981 through Dec. 1985, isolation of group A streptococci was attempted from throat swabs of pharyngitis patients of all ages, who visited a clinic in the central area of Yokohama-city. The data were analysed clinically and epidemiologically. The results were summarized as follows. 1) Group A streptococci were isolated from 85 (30.5%) out of 279 patients with pharyngitis. This is almost within the range of other reports. 2) During one year in the study period, no isolates of group A streptococci were obtained from throat swabs of 32 controls (healthy persons working in the clinic or patients without pharyngitis). 3) The isolation rate correlated with the presence of pharyngeal purulent exudate and also with high maximum body temperature after onset of the illness. The isolation rate was significantly higher in patients with these two signs than those without them. Therefore, these two signs are useful to predict group A streptococcal pharyngitis prior to laboratory examinations. 4) The isolation rate was high in the age groups under 10 and from 30 to 39. 5) The isolation rate was high in winter and low in summer. 6) The typing test revealed T types 13, 28 and 4 to be relatively frequent isolates.