There are conflicting reports on the effects of smoking on micro flora, with some studies reporting no difference in the prevalence of subgingival bacteria associated with periodontitis. However, data from the large Erie County study showed that the proportions of subjects positive for Aggregatibacter actinomycetamcomitans.gen.nov,[38] Porphyromonas gingivalis, and Tannerella forsythia[39] were higher among smokers,[40] and there are other reports of a higher prevalence of certain organisms in smokers.[41–43] Furthermore, increased counts of exogenous flora (Escherichia coli and Candida albicans) have been reported in smokers