Campylobacter Risk Associated with Poultry Manure Assessed07 March 2013
GERMANY - A laboratory study has revealed that Campylobacter may survive as long as six days in fresh hen manure, presenting a risk factor in the spread of this bacterium, which is associated with food-borne disease.
There is considerable potential for fresh faeces to transmit Campylobacter jejuni within and between flocks for six days, according to Hanover University researchers, and this six-day span should be considered when poultry manure is applied to land as organic fertiliser.
Infected laying hens regularly excrete large amounts of C.jejuni with their faeces, which represent a reservoir of infection within the flock and for animals in the region, according to M.F.M. Ahmed and colleagues at the University of Veterinary Medicine Hannover Foundation in their paper in Poultry Science recently.
Knowledge about survival times of C.jejuni in these faeces is scarce so they carried out exploratory laboratory experiments under controlled conditions to estimate the survival times of C.jejuni in artificially and naturally contaminated laying hen faeces.
From six different laying hen flocks - three Campylobacter-free and three Campylobacter-positive flocks - fresh excreta were randomly collected and pooled in 20-g samples per flock. In the laboratory, each of the three pooled samples from the Campylobacter-free barns were homogenised and mixed with 10mL of a freshly prepared C.jejuni suspension (3×108cfu per mL). The other three samples were only homogenised.
The six samples were stored at 20±1°C and 40 to 60 per cent relative humidity in two different incubators. Specimens of 2g were taken from all six samples one hour after storage and daily at the same time during the next 10 consecutive days and investigated on culturable C.jejuni.
The survival times of culturable C.jejuni ranged from 72 to 96 hours in artificially inoculated faeces and varied from 120 to 144 hours in naturally colonised flocks.
The flaA typing by RFLP confirmed that the isolates from the artificially contaminated faeces were identical with the added strain. A total of five different flaA types were identified from the naturally contaminated faeces, and survival of these isolates was dependent on flaA type.
The demonstrated survival times indicate that contaminated fresh faeces are an important reservoir of C.jejuni, representing a permanent source of infection over at least six days after excretion.
Ahmed M.F.M., J. Schulz and J. Hartung. 2013. Survival of Campylobacter jejuni in naturally and artificially contaminated laying hen feces. Poult. Sci. 92(2):364-369. doi: 10.3382/ps.2012-02496
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