bacteria-indicator-resistance-79.html
DANMAP 2015 3D
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danmap 2015 80
resistance
in indicator
bacteria
7. enterococci are included in the danmap programme to monitor
resistance
in gram-positive
bacteria
, while escherichia coli are included as representatives of gram-negative
bacteria
. in the early 90ties, focus was especially on
resistance
in gram-posi- tive
bacteria
, since most growth promotors used then targeted gram-positive
bacteria
. the chosen
bacteria
species were se- lected as indicators for occurrence of antimicrobial
resistance
in the different reservoirs through the food chain for several reasons: they are ubiquitous and present as major commensals in both the animal and human reservoirs; they can acquire an- timicrobial
resistance
as a response to selective pressures, and finally they have the potential for transferring
resistance
to pathogenic
bacteria
and can cause infection in humans. from enterococci, both enterococcus faecium and enterococcus fae- calis were used due to natural
resistance
to used antimicrobial agents such as flavomycin and streptogramins and observed differences in levels of
resistance
. 7.
resistance
in indicator
bacteria
highlights:
resistance
to tetracycline and erythromycin was observed at moderate to high levels in enterococcus faecalis from danish broilers and pigs as well as in
meat
thereof. during the last years,
resistance
levels in enterococci isolated from domestically produced broiler
meat
has increased and now approaches
resistance
levels found in imported
meat
. from 2014 to 2015, tetracycline
resistance
among enterococci from domestically produced broiler
meat
increased; an increase that is probably related to the increased use of tetracy- cline in the poultry production. for e. faecalis from pigs, levels of
resistance
to tetracycline, erythromycin and gentamicin has been declining to levels equal to or lower than 15 years ago.
resistance
levels have consistently been lower in e. faecalis from domestically pro- duced pork compared to isolates from the danish pigs.
resistance
to tetracycline is also lower in e. faecalis from domestically produced pork compared with isolates from imported pork. most of the enterococcus faecium from domestically produced beef and broiler
meat
, as well as from imported beef, were fully sensitive to all antimicrobial agents included in the test panel.
resistance
to tetracycline, ampicillin, erythromycin and ciprofloxacin was lower in e. faecium from domestically produced broiler
meat
compared with isolates from imported broiler
meat
. the occurrence of
resistance
to ampicillin, tetracycline, sulfonamides and trimethoprim increased significantly in indicator escherichia coli from broilers compared to 2014. this is most likely linked to the increased use of antimicrobial agents in the broiler production. in e. coli from danish broilers, pigs and
meat
thereof, approximately half of the isolates exhib- ited
resistance
to at least one of the antimicrobial agents tested, while the proportion of antimicrobial resistant isolates was remarkably low in isolates from danish cattle and beef. as in previous years, proportions of antimicrobial resistant e. coli were generally higher in imported
meat
than in domestically produced
meat
independent of the
meat
type (broiler
meat
, pork, beef). third-generation cephalosporin-resistant (esbl/ampc) e. coli were observed in pigs, cattle and
meat
thereof. the occurrence in pigs was higher than in 2009-2013, mainly due to a high frequency of samples containing e. coli with ampc upregulation. we consider that the changes in methodology implemented in 2015 may have had an important impact on the observed results.
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