Surveys of human enterotoxigenicEscherichia colifrom three different geographical areas for possible colonization factors

Abstract

Enterotoxigenic Escherichia coli (ETEC) from Burma, central Africa (Rwanda and Zaire) and Peru, were screened by enzyme-linked immunoassays for the colonization factor antigens (CFAs) and putative colonization factors (PCFs): CFA/I, CFA/II, which consists of three coli surface-associated (CS) antigens, CS1, CS2 and CS3, CFA/III, CFA/IV (CS4, CS5, CS6), CS7, PCFO9, PCFO159. H4, PCFO166, and CS17. The highest proportion of ETEC with identifiable colonization factors (71%) were found in the strains from Burma, which were mainly positive for CFA/I (38%), but strains producing CFA/II (4%), CFA/IV (11%), CS7 (10%), CS17 (4%), PCFO159, H4 (2%) and PCFO166 (2%) were also found. Sixty-nine percent of the ETEC from central Africa were positive for known colonization factors. While CFA/I positive strains were important (12%), a higher number of ETEC producing CFA/IV (33%) and CS17 (24%) were found. Fifty-two percent of the Peruvian strains produced identifiable colonization factors. The largest group of strains produced antigens of the CFA/IV complex (17%), while ETEC producing CFA/II (6%), CFA/III and CS6 (2%), CS7 (6%), PCFO9 (6%), PCFO166 (8%) and CS17 (7%) were also found. These surveys show that there is a considerable variation in the proportions and types of colonization factor found in different geographical areas. From 29 to 48% of the ETEC did not possess an identifiable colonization factor. These were particularly of the LT only producing type. These results have important implications for vaccine formulation.

Prevalence of Colonization Factor Antigens (CFAs) and Adherence to HeLa Cells in Enterotoxigenic Escherichia coli Isolated from Feces of Children in São Paulo

“…In this study, all 6 CFA/II strains presented CS1CS3, and five belonged to serotype 06 : H 16. In Argentina, the pattern CS1CS3 was more common than any other CFA/II pattern, also occurring mostly in 06 : H16 strains, but in Burma and Peru the CS1CS3 pattern did not occur, and all O6 : H16 strains presented CS2CS3 (2,27).…”

“…Similarly, in the other study from Sdo Paulo, CFA/I was more common than CFA/II (30). CFA/I was also the most frequently identified type in Chile, Argentina, and Burma (1,2,27). However, in Central Africa and Peru CFA/IV was the most common type identified, and some PCFs also occurred in elevated frequencies (27).…”

“…In a recent study conducted in Burma, Central Africa, and Peru, ETEC strains were screened for the presence of CFA/I, CFA/II, CFA/III, CFA/IV and several PCFs (27). The highest frequency of ETEC strains with identifiable CFAs (71%) was found in Burma, followed by Central Africa (69%) and Peru (52%).…”

Isolation of enterotoxigenicEscherichia colifrom British troops in Saudi Arabia

“…Strains of E. coli 0159 have been found in studies of travellers' diarrhoea [6], in surveys of the occurrence of human ETEC in underdeveloped areas [24] and from outbreaks of E. coli-associated diarrhoea [25,26]. These strains had the flagellar antigens 20 or 37, or were non-motile.…”

“…Only three strains in this study (6 %) had no identifiable colonization antigen, and two of them produced only LT. It has been suggested that strains of this type may produce less severe diarrhoea or may be nonpathogenic [24]. In the study of Wolf and colleagues [23] a much larger proportion of the ETEC strains (25 %) did not express a colonization antigen detectable by the assays used.…”