A multiplex PCR for detection of enterotoxin genes in Aeromonas species isolated from foods of animal origin and human diarrhoeal samples.

AIMS: The present study describes incidence and enterotoxin gene profile of Aeromonas spp. from human diarrhoeal samples (83) and raw meats (171). METHODS AND RESULTS: The samples were screened for isolation of Aeromonads. Aeromonas spp. contaminated raw meats of all kinds under the study and per cent contamination in chicken, mutton and beef was 14·03, 22·89 and 19·35, respectively. Of the 83 diarrhoeal samples from children, 6 (7·22%) were positive for presence of Aeromonas spp. Seven different species of Aeromonas (Aer. hydrophila, Aer. caviae, Aer. veronii bv sobria, Aer. trota, Aer. schubertii, Aer. jandaei and Aer. allosaccharophila) could be identified from foods and from diarrhoeal samples two species (Aer. caviae and Aer. hydrophila) were encountered. Unique primers were designed, and a multiplex PCR was standardized for detection of three enterotoxin genes (act, alt, ast) in the Aeromonas spp. Of the 39 isolates, 35 (89·74%) carried one or more enterotoxin genes: act, alt and ast genes were detected in 30 (76·92%), 31 (79·48%) and 4 (10·25%) isolates, respectively. The enterotoxin genes from a strain recovered from mutton were sequenced and submitted to GenBank and the accession no.s KC687135, KC633828 and KC687134 were provided for alt, ast and act, respectively, by the GenBank. CONCLUSIONS: The occurrence of enterotoxigenic Aeromonads in raw meats and diarrhoeal samples is a public health concern. SIGNIFICANCE AND IMPACT OF THE STUDY: Given the increasing evidence of involvement of Aeromonads in foodborne outbreaks, the standardization of single-step multiplex PCR will be helpful tool for detection of enterotoxin genes in Aeromonas spp.

Shiga toxin-producing Escherichia coli and enteropathogenic Escherichia coli in healthy goats in India: occurrence and virulence properties.

AIMS: To describe the occurrence and virulence gene pattern of shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) in healthy goats of Jammu and Kashmir, India. METHODS AND RESULTS: A total of 220 E. coli strains belonging to 60 different 'O' serogroups was isolated from 206 local (nonmigratory) and 69 migratory goats. All the 220 strains were screened for the presence of stx(1), stx(2), eaeA and hlyA genes. Twenty-eight E. coli (75.6%) strains from local and nine (24.3%) strains from migratory goats belonging to 18 different serogroups showed at least presence of one virulence gene studied. Twenty-eight strains (16.47%) (belonging to 13 different serogroups) from local goats carried stx(1) gene alone or in combination with stx(2) gene, while as only one strain (2%) from migratory goats possessed stx(2) gene alone. Interestingly in the present study none of the STEC strains carried eaeA gene. Similarly, none of the strains from local goats possessed eaeA and none of the migratory goats possessed stx(1) gene. Eight strains (16%) (belonging to four different serogroups) from migratory goats carried eaeA gene. Twenty-five (14.7%) and seven (14%) strains from local and migratory goats harboured hlyA gene respectively. CONCLUSIONS: Healthy goats of Jammu and Kashmir state serve as a reservoir of STEC and EPEC. Further studies in this direction are needed to work out whether or not they are transmitted to humans in this part of world. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first report of isolation of STEC and EPEC strains from healthy goats in Jammu and Kashmir State of India, which could be a source of infection to humans.