TY - JOUR
T1 - Prevalence and characteristics of Shiga toxin-producing Escherichia coli in finishing pigs
T2 - Implications on public health
AU - Cha, Wonhee
AU - Fratamico, Pina M.
AU - Ruth, Leah E.
AU - Bowman, Andrew S.
AU - Nolting, Jacqueline M.
AU - Manning, Shannon D.
AU - Funk, Julie A.
N1 - Funding Information:
This research was supported by the United States Department of Agriculture, National Institute of Food and Agriculture , (Grant number 2013-67005-21189 ).
Publisher Copyright:
© 2017
PY - 2018/1/2
Y1 - 2018/1/2
N2 - Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens, which can cause serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. To study the epidemiology of STEC in finishing pigs and examine the potential risks they pose for human STEC infections, we conducted a longitudinal cohort study in three finishing sites. Six cohorts of pigs (2 cohorts/site, 20 pigs/cohort) were randomly selected, and fecal samples (n = 898) were collected every two weeks through their finishing period. Eighty-two pigs (68.3%) shed STEC at least once, and the proportion of STEC-positive pigs varied across sites (50–97.5%) and cohorts (15–100%). Clinically important serotypes, O157:H7 (stx2c, eae) and O26:H11 (stx1a, eae), were recovered from two pigs at sites C and A, respectively. The most common serotype isolated was O59:H21 (stx2e), which was particularly prevalent in site B as it was recovered from all STEC positive pigs (n = 39). Each cohort showed different patterns of STEC shedding, which were associated with the prevalent serotype. The median shedding duration of STEC in pigs was 28 days, consistent with our prior study. However, among pigs shedding O59:H21 at least once, pigs in cohort B2 had a significantly longer shedding duration of 42 days (P < 0.05) compared to other cohorts. Stx2e was the most commonly observed stx variant in finishing pigs (93.9%), in accordance with the previous studies. Stx2e has been reported to be significantly associated with edema disease in pigs, however, the pathogenicity in humans warrants further investigations. Nonetheless, our findings affirm that pigs are an important reservoir for human STEC infections, and that the circulating serotypes in a cohort and site management factors may significantly affect the prevalence of STEC. Molecular characterization of STEC isolates and epidemiological studies to identify risk factors for shedding in pigs are strongly warranted to further address the significance to public health and to develop mitigation strategies.
AB - Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens, which can cause serious illnesses, including hemorrhagic colitis and hemolytic uremic syndrome. To study the epidemiology of STEC in finishing pigs and examine the potential risks they pose for human STEC infections, we conducted a longitudinal cohort study in three finishing sites. Six cohorts of pigs (2 cohorts/site, 20 pigs/cohort) were randomly selected, and fecal samples (n = 898) were collected every two weeks through their finishing period. Eighty-two pigs (68.3%) shed STEC at least once, and the proportion of STEC-positive pigs varied across sites (50–97.5%) and cohorts (15–100%). Clinically important serotypes, O157:H7 (stx2c, eae) and O26:H11 (stx1a, eae), were recovered from two pigs at sites C and A, respectively. The most common serotype isolated was O59:H21 (stx2e), which was particularly prevalent in site B as it was recovered from all STEC positive pigs (n = 39). Each cohort showed different patterns of STEC shedding, which were associated with the prevalent serotype. The median shedding duration of STEC in pigs was 28 days, consistent with our prior study. However, among pigs shedding O59:H21 at least once, pigs in cohort B2 had a significantly longer shedding duration of 42 days (P < 0.05) compared to other cohorts. Stx2e was the most commonly observed stx variant in finishing pigs (93.9%), in accordance with the previous studies. Stx2e has been reported to be significantly associated with edema disease in pigs, however, the pathogenicity in humans warrants further investigations. Nonetheless, our findings affirm that pigs are an important reservoir for human STEC infections, and that the circulating serotypes in a cohort and site management factors may significantly affect the prevalence of STEC. Molecular characterization of STEC isolates and epidemiological studies to identify risk factors for shedding in pigs are strongly warranted to further address the significance to public health and to develop mitigation strategies.
KW - Cohort
KW - Finishing pigs
KW - Prevalence
KW - Shedding duration
KW - Shiga toxin-producing Escherichia coli
UR - http://www.scopus.com/inward/record.url?scp=85032209084&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85032209084&partnerID=8YFLogxK
U2 - 10.1016/j.ijfoodmicro.2017.10.017
DO - 10.1016/j.ijfoodmicro.2017.10.017
M3 - Article
C2 - 29080423
AN - SCOPUS:85032209084
SN - 0168-1605
VL - 264
SP - 8
EP - 15
JO - International Journal of Food Microbiology
JF - International Journal of Food Microbiology
ER -