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Intermittent and persistent shedding of Escherichia coli O157 in cohorts of naturally infected calves
Author(s) -
Robinson S.E.,
Wright E.J.,
Hart C.A.,
Bennett M.,
French N.P.
Publication year - 2004
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2004.02390.x
Subject(s) - feces , biology , escherichia coli , zoology , veterinary medicine , immunomagnetic separation , microbiology and biotechnology , enterobacteriaceae , pathogen , medicine , biochemistry , gene
Aims: We conducted two short‐term studies of cohorts of naturally infected calves to determine the prevalence and concentrations of Escherichia coli O157 shed in faeces. Methods and Results: Two cohorts of calves were sampled; in the first study 14 calves were sampled up to five times a day for 5 days; in the second study a group of 16 separate calves were sampled once or twice a day for 15 days. All cattle within the two cohorts shed E. coli O157 at some point during the respective studies. In 18% of samples, E. coli O157 could only be isolated using immunomagnetic separation after an enrichment period, suggesting concentrations <250 CFU g −1 . The highest concentrations recorded were 6·7 × 10 5 and 1·6 × 10 6 CFU g −1 for studies 1 and 2 respectively. Conclusions: Persistent, high shedders (shedding >10 3 CFU g −1 ) were evident in both studies but, in the majority of calves, the pathogen was isolated intermittently. Significance and Impact of the Study: The variable patterns of shedding have important implications for the design of appropriate sampling protocols and for gaining meaningful estimates of parameters used in mathematical models of transmission.