Prevalence and distribution of bacteriophage φAa DNA in strains of Actinobacillus actinomycetemcomitans Free

φAa is a bacteriophage that was originally isolated by induction of a lysogenic strain of the oral bacterium Actinobacillus actinomycetemcomitans. Since the discovery of phage φAa, additional phages infecting several other strains of A. actinomycetemcomitans have been identified. To determine the prevalence of φAa or φAa-related temperate phages in this species, a φAa-specific DNA probe was prepared to screen for homologous sequences among 42 strains of A. actinomycetemcomitans. Fourteen (33%) of the 42 strains examined contained DNA sequences that hybridized with the phage φAa probe. A bacteriophage designated φAa₃₃₃₈₄ was isolated by induction from one of the strains (ATCC 33384) that contained a sequence that hybridized with the φAa probe. The φAa probe hybridized with the DNA extracted from bacteriophage φAa₃₃₃₈₄. The distribution of the phage φAa sequence among A. actinomycetemcomitans serotypes was 5/13 (38%) of the serotype a strains, 0/16 (0%) of the serotype b strains, and 9/13 (69%) of the serotype c strains. The results of this investigation suggest that the target sequence prepared from the phage φAa genome is fairly common in the A. actinomycetemcomitans chromosome, and that the sequence is distributed among the A. actinomycetemcomitans serotypes in a seemingly nonrandom manner.