Enterotoxigenic and non-enterotoxigenic Bacteroides fragilis from fecal microbiota of children

Enterotoxigenic Bacteroides fragilis (ETBF) is an important part of the human and animal intestinal microbiota and is commonly associated with diarrhea. ETBF strains produce an enterotoxin encoded by the bft gene located in the B. fragilis pathogenicity island (BfPAI). Non-enterotoxigenic B. fragilis (NTBF) strains lack the BfPAI and usually show two different genetic patterns, II and III, based on the absence or presence of a BfPAI-flanking region, respectively. The incidence of ETBF and NTBF strains in fecal samples isolated from children without acute diarrhea or any other intestinal disorders was determined. All 84 fecal samples evaluated were B. fragilis-positive by PCR, four of them harbored the bft gene, 27 contained the NTBF pattern III DNA sequence, and 52 were considered to be NTBF pattern II samples. One sample was positive for both ETBF and NTBF pattern III DNA sequences. All 19 B. fragilis strains isolated by the culture method were bft-negative, 9 belonged to pattern III and 10 to pattern II. We present an updated overview of the ETBF and NTBF incidence in the fecal microbiota of children from Sao Paulo City, Brazil.

Prevalence of Porphyromonas gingivalis and Bacteroides forsythus in chronic periodontitis by multiplex PCR

Periodontitis is a common inflammatory and infectious disease which destroys the supporting structure of the teeth. Recent studies show that periodontal infection significantly increases the risk of some systemic diseases. It is generally accepted that bacterial species notably Porphyromonas gingivalis and Bacteroides fosythus are highly associated with periodontium. Molecular methods such as Multiplex PCR seem to be more sensitive and faster. Multiplex PCR alone can lower the limit of bacterial detection. Several pathogens can be detected simultaneously by this method. The Subgingival plaque samples from 61 patients including 34 women and 27 men in the age range of 24-69 years and an average age of 43 suffering from chronic periodontitis with probing depth of PD>/=6, and from 40 periodontally healthy controls including 22 women and 18 men in the age range of 21-69 years and an average age of 41.35 were collected by sterile curette. In this study, two species-specific forward primers were used in combination with a single reverse primer. The samples' DNA was extracted and Multiplex PCR was administered. Porphyromonas gingivalis was detected in 51 samples [81.61%] and 16 samples [40%] of the chronic periodontitis patients and the healthy subjects repectively. Moreover, Bacteroides forsythus was detected 32 samples [52.50%] of the chronic periodontitis patients but it was not detected in any of the samples from the healthy group. P. gingivalis and B. forsythus can be simultaneously detected using Multiplex PCR. The present data suggest that P. gingivalis is a more important factor in the etiology of chronic periodontitis. Further studies are needed to determine the spectrum of pathogenicity of the disease and effective management of diagnosis and treatment in order to decrease the risk of periodontal complications such as systemic infections