BfR | Annual Report 2013
34
Evaluation of the transmission of resistant bacteria to
humans
Besides the possibility of a reduced ability to treat animals, the signifi-
cance of resistant bacteria originating from livestock farming lies above
all in the possible transmission of resistant bacteria to humans by direct
contact, but also via food. In another collaborative research project,
“MedVetStaph”, sponsored by the Federal Ministry of Research, the
BfR is therefore primarily examining the transmission of methicillin-re-
sistant
Staphylococcus aureus
(MRSA) along the food chain. Evaluation
shows that while a significant reduction in bacterial contamination can
be achieved in the slaughtering of pigs, in poultry slaughtering bacteria
that have been brought in are transferred to the animal carcasses to a
significant extent and therefore to fresh meat.
Studies with sensitive detection methods that the BfR supervised within
the framework of the similarly sponsored RESET collaborative project
showed furthermore that ESBL and AmpC-producing
E. coli
are found
not only in livestock animals, but also on raw meat and other foods. The
results from molecular characterisation of the bacteria indicate that hu-
mans and animals in some cases have the same or similar ESBL types.
There are, however, also bacteria types among humans that have never
been observed in any of the animal reservoirs examined. Moreover,
these studies have led to the sporadic detection of carbapenemase-
producing
Salmonella
spp. and
E. coli
. Since carbapenems are often
the last line of defence in the treatment of serious infections in humans,
the spread of resistances against this class of antimicrobial must be
prevented. The use of carbapenems is generally not permitted for ani-
mals. Any detected occurrence of such resistances must therefore be
closely monitored.
The BfR conducts scientific studies to out-
line suitable courses of action to minimise
the entry of resistant bacteria into the food
chain and assesses their effect.
>>
BfR studies on the transferability of
resistant bacteria to humans show that
it is above all during poultry slaughter-
ing that bacteria are transferred to the
carcasses and therefore to fresh meat.
