Microbiological evaluation of periapical infections in Egypt.

This study identifies and correlates proportions of bacteria in periapically involved anterior teeth of 85 adult Egyptian patients. Affected sites were free from caries and periodontal disease but had a history of trauma. The mean number of component bacterial species per specimen was 3.1. Anaerobic bacteria were the dominant flora present in specimen cultures, comprising 73% (190/259) of cultivable bacteria. The most frequently isolated organisms were Eubacterium species (68%), black-pigmented Bacteroides (56%), Streptococcus morbillorum (47%) and non-pigmented Bacteroides (37%). These organisms also showed the highest proportional values relative to total cultivable bacteria. The mean percentages of total viable counts of these isolates were 19.0%, 14.1%, 18.0% and 15.5%, respectively. Statistical analysis of data revealed a significant negative correlation between S. morbillorum and Bacteroides species.