Abstract:
Shiga-toxin-producing Escherichia coli is a foodborne pathogen commonly associated with
human disease characterized by mild or bloody diarrhea hemorrhagic colitis and hemolytic uremic
syndrome. This study investigated the occurrence of STEC in fecal samples of 289 goats in South
Africa using microbiological culture and PCR. Furthermore, 628 goat STEC isolates were characterized
by serotype (O:H) and major virulence factors by PCR. STEC was found in 80.2% (232/289) of goat
fecal samples. Serotyping of 628 STEC isolates revealed 63 distinct serotypes including four of the
major top seven STEC serogroups which were detected in 12.1% (35/289) of goats: O157:H7, 2.7%
(8/289); O157:H8, 0.3%, (1/289); O157:H29, 0.3% (1/289); O103:H8, 7.6% (22/289); O103:H56, 0.3%
(1/289); O26:H2, 0.3% (1/289); O111:H8, 0.3% (1/289) and 59 non-O157 STEC serotypes. Twenty-four
of the sixty-three serotypes were previously associated with human disease. Virulence genes were
distributed as follows: stx1, 60.6% (381/628); stx2, 72.7% (457/628); eaeA, 22.1% (139/628) and hlyA,
78.0% (490/628). Both stx1 and stx2 were found in 33.4% (210/628) of isolates. In conclusion, goats
in South Africa are a reservoir and potential source of diverse STEC serotypes that are potentially
virulent for humans. Further molecular characterization will be needed to fully assess the virulence
potential of goat STEC isolates and their capacity to cause disease in humans.
