Abstract
Introduction: Pathogenic Escherichia coli has been listed among the most important bacteria associated with foodborne illnesses around the world. We investigated the genetic relatedness among Shiga toxin-producing E. coli (STEC) isolated along the animal food supply chain and from humans diagnosed with gastroenteritis in Qatar. Methods: Samples were collected from different sources along the food supply chain and from patients admitted to the hospital with complaints of gastroenteritis. All samples were screened for the presence of E. coli O157:H7 and non-O157 STEC using a combination of bacterial enrichment and molecular detection techniques. A proportional sampling approach was used to select positive samples from each source for further multilocus sequence typing (MLST) analysis. Seven housekeeping genes described for STEC were amplified by polymerase chain reaction, sequenced, and analyzed by MLST. Isolates were characterized by allele composition, sequence type (ST) and assessed for epidemiologic relationship within and among different sources. Nei's genetic distance was calculated at the allele level between sample pools in each site downstream. Results: E. coli O157:H7 occurred at a higher rate in slaughterhouse and retail samples than at the farm or in humans in our sampling. The ST171, an ST common to enterotoxigenic E. coli and atypical enteropathogenic E. coli, was the most common ST (15%) in the food supply chain. None of the genetic distances among the different sources was statistically significant. Conclusion: Enterohemorrhagic E. coli pathogenic strains are present along the supply chain at different levels and with varying relatedness. Clinical isolates were the most diverse, as expected, considering the polyclonal diversity in the human microbiota. The high occurrence of these food adulterants among the farm products suggests that implementation of sanitary measures at that level might reduce the risk of human exposure.
| Original language | English |
|---|---|
| Pages (from-to) | 318-325 |
| Number of pages | 8 |
| Journal | Foodborne Pathogens and Disease |
| Volume | 14 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 1 Jun 2017 |
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Keywords
- E. coliO157:H7
- epidemiology
- food adulterants
- food chain
- gastroenteritis (foodborne illness),MLST
ASJC Scopus subject areas
- Microbiology
- Food Science
- Applied Microbiology and Biotechnology
- Animal Science and Zoology
Cite this
Genetic relatedness among Shiga toxin-producing Escherichia coli isolated along the animal food supply chain and in gastroenteritis cases in Qatar using multilocus sequence typing. / Palanisamy, Srikanth; Chang, Yu Chen; Scaria, Joy; Penha Filho, Rafael Antonio Casarin; Peters, Kenlyn E.; Doiphode, Sanjay H.; Sultan, Ali; Mohammed, Hussni O.
In: Foodborne Pathogens and Disease, Vol. 14, No. 6, 01.06.2017, p. 318-325.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Genetic relatedness among Shiga toxin-producing Escherichia coli isolated along the animal food supply chain and in gastroenteritis cases in Qatar using multilocus sequence typing
AU - Palanisamy, Srikanth
AU - Chang, Yu Chen
AU - Scaria, Joy
AU - Penha Filho, Rafael Antonio Casarin
AU - Peters, Kenlyn E.
AU - Doiphode, Sanjay H.
AU - Sultan, Ali
AU - Mohammed, Hussni O.
PY - 2017/6/1
Y1 - 2017/6/1
N2 - Introduction: Pathogenic Escherichia coli has been listed among the most important bacteria associated with foodborne illnesses around the world. We investigated the genetic relatedness among Shiga toxin-producing E. coli (STEC) isolated along the animal food supply chain and from humans diagnosed with gastroenteritis in Qatar. Methods: Samples were collected from different sources along the food supply chain and from patients admitted to the hospital with complaints of gastroenteritis. All samples were screened for the presence of E. coli O157:H7 and non-O157 STEC using a combination of bacterial enrichment and molecular detection techniques. A proportional sampling approach was used to select positive samples from each source for further multilocus sequence typing (MLST) analysis. Seven housekeeping genes described for STEC were amplified by polymerase chain reaction, sequenced, and analyzed by MLST. Isolates were characterized by allele composition, sequence type (ST) and assessed for epidemiologic relationship within and among different sources. Nei's genetic distance was calculated at the allele level between sample pools in each site downstream. Results: E. coli O157:H7 occurred at a higher rate in slaughterhouse and retail samples than at the farm or in humans in our sampling. The ST171, an ST common to enterotoxigenic E. coli and atypical enteropathogenic E. coli, was the most common ST (15%) in the food supply chain. None of the genetic distances among the different sources was statistically significant. Conclusion: Enterohemorrhagic E. coli pathogenic strains are present along the supply chain at different levels and with varying relatedness. Clinical isolates were the most diverse, as expected, considering the polyclonal diversity in the human microbiota. The high occurrence of these food adulterants among the farm products suggests that implementation of sanitary measures at that level might reduce the risk of human exposure.
AB - Introduction: Pathogenic Escherichia coli has been listed among the most important bacteria associated with foodborne illnesses around the world. We investigated the genetic relatedness among Shiga toxin-producing E. coli (STEC) isolated along the animal food supply chain and from humans diagnosed with gastroenteritis in Qatar. Methods: Samples were collected from different sources along the food supply chain and from patients admitted to the hospital with complaints of gastroenteritis. All samples were screened for the presence of E. coli O157:H7 and non-O157 STEC using a combination of bacterial enrichment and molecular detection techniques. A proportional sampling approach was used to select positive samples from each source for further multilocus sequence typing (MLST) analysis. Seven housekeeping genes described for STEC were amplified by polymerase chain reaction, sequenced, and analyzed by MLST. Isolates were characterized by allele composition, sequence type (ST) and assessed for epidemiologic relationship within and among different sources. Nei's genetic distance was calculated at the allele level between sample pools in each site downstream. Results: E. coli O157:H7 occurred at a higher rate in slaughterhouse and retail samples than at the farm or in humans in our sampling. The ST171, an ST common to enterotoxigenic E. coli and atypical enteropathogenic E. coli, was the most common ST (15%) in the food supply chain. None of the genetic distances among the different sources was statistically significant. Conclusion: Enterohemorrhagic E. coli pathogenic strains are present along the supply chain at different levels and with varying relatedness. Clinical isolates were the most diverse, as expected, considering the polyclonal diversity in the human microbiota. The high occurrence of these food adulterants among the farm products suggests that implementation of sanitary measures at that level might reduce the risk of human exposure.
KW - E. coliO157:H7
KW - epidemiology
KW - food adulterants
KW - food chain
KW - gastroenteritis (foodborne illness),MLST
UR - http://www.scopus.com/inward/record.url?scp=85020740686&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85020740686&partnerID=8YFLogxK
U2 - 10.1089/fpd.2016.2209
DO - 10.1089/fpd.2016.2209
M3 - Article
VL - 14
SP - 318
EP - 325
JO - Foodborne Pathogens and Disease
JF - Foodborne Pathogens and Disease
SN - 1535-3141
IS - 6
ER -