Vania M. Carvalho1,2, DVM, MSc; Carlton L. Gyles3, DVM, PhD; Kim Ziebell4, PhD; Marcela A. Ribeiro2; José L. Catão-Dias5,6, DVM, PhD; Idércio L. Sinhorini5, DVM, PhD; Luiz R. Trabulsi7, PhD; Rogéria Keller7, PhD; Juana A.G. Ordoñez7, PhD; Antônio F. Pestana de Castro2, DVM, PhD
1Laboratório Multidisciplinar de Clínica e Doenças Infecciosas, Universidade Paulista, São Paulo, State of São Paulo, Brazil; 2Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, State of São Paulo, Brazil; 3Department of Pathobiology, University of Guelph, Guelph, ON, Canada; 4Health Canada Laboratory for Foodborne Zoonoses, Guelph, ON, Canada; 5Departamento de Patologia, Faculdade de Medicina Veterinária e Zootecnica, Universidade de São Paulo, São Paulo, State of São Paulo, Brazil; 6Fundação Parque Zoológico de São Paulo, State of São Paulo, Brazil; 7Laboratório de Bacteriologia Especial, Instituto Butantan, São Paulo, State of São Paulo, Brazil
Enteropathogenic Escherichia coli (EPEC) has been associated with acute infantile diarrhea and is a leading cause of human mortality in developing countries. While diarrhea is also a major problem among primates kept in captivity, the role of Escherichia coli is still unclear.1
This study was designed to characterize diarrheagenic E. coli recovered from the feces of 56 New World non-human primates, primarily marmosets (Callithrix spp.), ranging in age from 3 weeks to 6 years. Seventeen of the 56 primates demonstrated signs of diarrhea and/or enteritis. E. coli recovered from animal stools were tested by polymerase chain reaction (PCR) for genes encoding virulence factors of diarrheagenic E. coli and for adherence capacity (HeLa cell assay).2 In addition, isolates were characterized in terms of attaching and effacing lesion by the fluorescence actin staining test (FAS)3 and by electron microscopy.
PCR was positive for the eae gene in 10 (27%) of the 39 animals without clinical diarrhea or enteritis and positive in eight (47%) of animals with clinical signs. Samples of intestinal tissues from animals found by PCR to be eae+ E. coli were stained with hematoxylin-eosin (HE) and toluidine blue. Colonies of eae+ E. coli were serotyped and examined by PCR for genes encoding virulence markers.
Typical and atypical EPEC serotypes were recovered from healthy and sick animals, with several isolates demonstrating pathogenic virulence markers responsible for overt signs of disease in a host. Histologic examination of intestinal tissue from sick animals revealed a moderate neutrophilic and mononuclear cell infiltrate in the lamina propria and submucosa, with atrophic crypts.
The typical and atypical EPEC strains recovered from both healthy and sick non-human primates demonstrated virulence-associated attributes similar to those of EPEC strains implicated in human disease. From the results presented here, EPEC could represent a significant pathogen for non-human primates, deserving further investigation. Due to similarities between human cases and the animals investigated in this study, marmosets could represent an important model for EPEC in humans.
This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (grant #99/09459-7) and Conselho Nacional para o Desenvolvimento Científico e Técnológico (CNPq).
1. Cravioto, A., A. Tello, and A. Navarro. 1991. Association of Escherichia coli HEp-2 adherence patterns with type and duration of diarrhoea. Lancet. 337:262–264.
2. Knutton, S., T. Baldwin, P.H. Williams, and A.S. McNeish. 1989. Actin accumulation at sites of adhesion to tissue culture cells: basis of a new diagnostic test for enteropathogenic and enterohemorrhagic Escherichia coli. Infect Immunol. 57:1290–1298.
3. Nataro, J.P., and J.B. Kaper. 1998. Diarrheagenic Escherichia coli. Clin Microbiol Rev. 11:142–201.