TY - JOUR

T1 - Carriage and fecal counts of CTX-M-producing Escherichia coli in pigs

T2 - A longitudinal study

AU - Hansen, Katrine Hartung

AU - Damborg, Peter

AU - Andreasen, Margit

AU - Nielsen, Søren Saxmose

AU - Guardabassi, Luca

PY - 2013/3/1

Y1 - 2013/3/1

N2 - Current knowledge on extended-spectrum beta-lactamases (ESBLs) in animals is based largely on cross-sectional studies and qualitative data. The aim of this longitudinal study was to elucidate carriage proportions and fecal counts of ESBL-producing Escherichia coli in pigs during the production cycle. At each of three ESBL-positive single-sited farrow-to-finisher pig farms (farms A, B, and C) included in the study, individual fecal samples were taken from 17 to 20 sows 1 week before farrowing and from 2 piglets of each sow's litter four times from birth to slaughter (as piglets, weaners, and finishers). Cefotaxime (CTX)-resistant coliforms in feces were counted on MacConkey agar containing 2 μg/ml CTX and characterized for the presence of ESBL-encoding genes by PCR and sequencing. CTX-M-positive pigs were detected in all age groups at farms A (bla CTX-M-9 group, compatible with bla CTX-M-14/17) and B (bla CTX-M-1 group, compatible with bla CTX-M-1/61), whereas only three weaners were positive at farm C (bla CTX-M-1 group, compatible with bla CTX-M-1/61). A significant decrease in carriage was detected during the production cycle, with on average 50% carriage immediately after birth, 58% just before weaning, 29% during weaning, and 12% during finishing. The observed reduction in numbers of CTX-M-positive pigs was accompanied by a significant reduction in mean fecal counts of CTX-resistant coliforms from ∼107 CFU/g in piglets to ∼103 CFU/g in finishers (P < 0.001). These findings provide novel information about the epidemiology of ESBLs at the farm level and have important implications for assessments of risks of meat contamination during slaughter.

AB - Current knowledge on extended-spectrum beta-lactamases (ESBLs) in animals is based largely on cross-sectional studies and qualitative data. The aim of this longitudinal study was to elucidate carriage proportions and fecal counts of ESBL-producing Escherichia coli in pigs during the production cycle. At each of three ESBL-positive single-sited farrow-to-finisher pig farms (farms A, B, and C) included in the study, individual fecal samples were taken from 17 to 20 sows 1 week before farrowing and from 2 piglets of each sow's litter four times from birth to slaughter (as piglets, weaners, and finishers). Cefotaxime (CTX)-resistant coliforms in feces were counted on MacConkey agar containing 2 μg/ml CTX and characterized for the presence of ESBL-encoding genes by PCR and sequencing. CTX-M-positive pigs were detected in all age groups at farms A (bla CTX-M-9 group, compatible with bla CTX-M-14/17) and B (bla CTX-M-1 group, compatible with bla CTX-M-1/61), whereas only three weaners were positive at farm C (bla CTX-M-1 group, compatible with bla CTX-M-1/61). A significant decrease in carriage was detected during the production cycle, with on average 50% carriage immediately after birth, 58% just before weaning, 29% during weaning, and 12% during finishing. The observed reduction in numbers of CTX-M-positive pigs was accompanied by a significant reduction in mean fecal counts of CTX-resistant coliforms from ∼107 CFU/g in piglets to ∼103 CFU/g in finishers (P < 0.001). These findings provide novel information about the epidemiology of ESBLs at the farm level and have important implications for assessments of risks of meat contamination during slaughter.

U2 - 10.1128/AEM.02399-12

DO - 10.1128/AEM.02399-12

M3 - Comment/debate

AN - SCOPUS:84874808887

VL - 79

SP - 794

EP - 798

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

SN - 0099-2240

IS - 3

ER -