Primary fecal culture used as template for PCR detection of diarrheagenic E. coli virulence factors.
The PCR technique applied to primary fecal cultures (PFC-PCR) was compared to the usual method employing isolated colonies (IC-PCR) in order to assess its sensitivity in the detection of virulence markers of diarrheagenic Escherichia coli in fecal samples obtained from children with diarrhea. Among the 149 samples analysed, PFC-PCR detected 81(54.4%) samples presenting one or two virulence markers, while IC-PCR detected only 59 (39.6%) positive samples. The markers detected in order of frequency were: pAA, LT-I, eaeA, ST-I, daaE, and ipaH. The PFC-PCR method of detection of diarrheagenic E. coli virulence markers proved to be reliable and more sensitive (p<0.05) than the usual method employing isolated colonies. It has also the advantage of being faster and less expensive than the detection methods in current use.
Departamento de Bacteriologia, Instituto Oswaldo Cruz-FIOCRUZ, Av. Brasil 4365, 21045-900, RJ, Rio de Janeiro, Brazil.
Sheila
S
da Silva Duque
Rosa Maria
RM
Silva
Aderbal
A
Sabra
Leila Carvalho
LC
Campos
D002675:Child, Preschool; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity*; D005243:Feces / Q000382:microbiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016133:Polymerase Chain Reaction / Q000379:methods*; D014774:Virulence