The majority of enteroaggregative Escherichia coli strains produce the E. coli common pilus when adhering to cultured epithelial cells.
Enteroaggregative Escherichia coli (EAEC) have emerged as a significant worldwide cause of chronic diarrhea in the pediatric population and in HIV patients. The vast majority of EAEC strains do not produce the aggregative adherence fimbriae I-III (AAFs) so far reported and thus, what adherence factors are present in these strains remains unknown. Here, we investigated the prevalence of the chromosomal E. coli common pilus (ECP) genes and ECP production amongst 130 EAEC strains of diverse origin as well as the role of ECP in EAEC adherence. Through multiplex PCR analysis we found that 96% of EAEC strains contained the ecpA structural pilin gene whereas only 3.1% and 5.4% were positive for AAF fimbrial genes aggA or aafA, respectively. Among the ecpA(+) strains, 63% produced ECP when adhering to cultured epithelial cells. An ecpA mutant derived from prototypic strain 042 (AAF/II(+)) was not altered in adherence suggesting that the AAF/II, and not ECP, plays a major role in this strain. In contrast, strain 278-1 (AAF(-)) deleted of the ecpA gene was significantly reduced in adherence to cultured epithelial cells. In all, these data indicate a potential role of ECP in adherence for EAEC strains lacking the known AAFs and that in association with other adhesive determinants, ECP may contribute to their survival and persistence within the host and in the environment.
Avelino
Fabiola
F
Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Pue 72000, Mexico.
Saldaña
Zeus
Z
Islam
Sohidul
S
Monteiro-Neto
Valerio
V
Dall'Agnol
Monique
M
Eslava
Carlos A
CA
Girón
Jorge A
JA
D018829:Adhesins, Bacterial / Q000235:genetics; D018830:Adhesins, Escherichia coli / Q000235:genetics; D001422:Bacterial Adhesion; D004269:DNA, Bacterial / Q000235:genetics; D004847:Epithelial Cells / Q000382:microbiology*; D004926:Escherichia coli / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics; D036781:Fimbriae Proteins / Q000235:genetics; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000502:physiology*; D006801:Humans; D016133:Polymerase Chain Reaction
C108511:AafA protein, E coli; D018829:Adhesins, Bacterial; D018830:Adhesins, Escherichia coli; C079725:AggA protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins