[Interrelationship between toxigenic and non-toxigenic diphtheria microbes in the epidemic process]

A study of the circulation of toxigenic and nontoxigenic diphtheria bacilli was carried out in several carrier state foci under conditions of a natural course of the epidemic process. There were 2623 persons under observation. A total of 32158 analyses were carried out, and 2271 strains were isolated and studied. No formation of the toxigenic variants of diphtheria bacillus as a result of phage conversion was revealed in the foci of carrier state despite the wide spread in them of nontoxigenic lysosensitive cultures capable of acquiring the toxigenic properties under experimental conditions, and of the cultures which had converting corinephages. Thus, autonomy of the circulation of the toxigenic and nontoxigenic diphtheria bacilli occurred in the carrier state foci; the leading role in the change of the diphtheria bacillus type belonged to reinfection.