PEQUEÑA SEÑAL
6 MANEJO DE LA HERRAMIENTA DE SIMULACIÓN PSD
6.2 Opciones de Menú
DANMAP 2009
Table 21. Occurrence of resistance (%) among Escherichia coli from food animals, food of Danish and imported origin, Denmark
Substance Broilers Cattle Pigs Broiler meat Beef Pork meat
Danish
% Danish % Danish% Danish % Imported % Danish % Imported % Danish % Imported %
Tetracycline 12 2 35 11 55 3 5 32 48 Chloramphenicol 1 1 5 1 21 0 0 1 8 Florfenicol 1 1 1 0 0 0 0 0 2 Ampicillin 18 2 26 20 55 3 5 29 28 Cephalothin - - - - Ceftiofur 1 0 0 0 4 0 0 1 0 Cefpodoxime - - - - Cefotaxime 0 0 0 0 4 0 0 1 0 Sulfonamide 14 3 33 8 54 3 5 38 34 Trimethoprim 6 0 19 3 38 0 5 25 31 Apramycin 0 0 0 1 2 0 0 0 0 Gentamicin 0 0 0 2 5 0 0 0 0 Neomycin 0 0 6 1 14 0 5 6 0 Spectinomycin 3 0 25 2 28 0 0 16 18 Streptomycin 9 3 43 10 45 3 5 42 35 Ciprofloxacin 12 0 1 4 41 0 0 1 6 Nalidixic acid 11 0 1 4 40 0 0 1 2 Colistin 0 0 0 0 4 0 0 0 0 Number of isolates 152 94 150 143 221 32 39 106 65
E. coli isolates from healthy food producing animals
originated from samples collected for the DANMAP program at the time of slaughter. For broilers, isolation and susceptibility testing was performed at the National Veterinary Institute and for cattle and pigs at the National Food Institute. E.coli from food originated from meat sampled at wholesale and retail outlets, collected randomly in all regions of Denmark by the Danish Veterinary and Food Administration Regional laboratories in two centrally coordinated programs. The susceptibility testing was done at the National Food Institute. In 2009, no samples were collected from healthy humans.
Escherichia coli from food animals
E. coli was isolated from 279 out of 284 samples from
pigs, 156 out of 161 samples from cattle, and 257 out of 398 samples from broilers. Not more than one isolate was included per positive farm. A randomly selected subsample of 150, 94 and 152 isolates from pigs, cattle and broilers, respectively, were susceptibility tested and reported.
Among animal species, the level of resistance in indicator E. coli was lowest in isolates from cattle, with 95% of the isolates being fully susceptible to all tested antimicrobial agents. Among the tested broiler isolates, 57% were fully susceptible and 8% were
multi resistant (resistant to three or more antimicrobial classes). Among isolates from pigs the proportion of fully susceptible isolates decreased from 57% fully susceptible in 2008 to 43% in 2009; 37% of the isolates from pigs were multi resistant.
The occurence of resistance in 2009 is shown in Table 21.Trends in resistance to selected antimicrobial agents in isolates from production animals (2000–2009) are presented in Figure 34. The MIC distributions for 2009 are shown in Table 52 in Appendix 1. In general, the highest resistance level was found in E. coli from pigs, except for fluoroquinolone (nalidixic acid and ciprofloxacin) resistance, which was higher in E. coli from broilers throughout the whole study period (2000– 2009). The low level of fluoroquinolone resistance in
E. coli from Danish pigs and cattle probably reflects
the low consumption since 2002, where the use in production animals was restricted; since 2002, the highest fluoroquinolone consumption was seen in poultry, as reflected in the higher resistance level. However, the fluoroquinolone consumption in the broiler production (including rearing) has decreased by 98% from 2004–2008, but increased again in 2009. Fluoroquinolone resistance in E. coli from broilers, pigs and cattle has not increased through the past decade. In 2009, one ceftiofur resistant E. coli was isolated from broilers. This is to our knowledge the first cephalosporin resistant E. coli isolated from broilers in Denmark. Cephalosporins have not been used in the
DANMAP 2009
Figure 34. Trends in resistance to selected antimicrobial agents among Escherichia coli from food animals, Denmark
0
20
40
60
80
100
00 01 02 03 04 05 06 07 08 09 00 01 02 03 04 05 06 07 08 09 00 01 02 03 04 05 06 07 08 09%
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Ampicillin Ciprofloxacin Sulfonamide Tetracycline Streptomycin
Broilers
Cattle
Pigs
broiler production in Denmark in 2001–2009, but may have been used in day-old chicks imported for rearing of parents flocks, or in grand parent floxk abroad. Findings consistent with vertical – not horizontal – transmission of ampicillin- and nalidixic acid-resistant
E. coli through the broiler production system has been
demonstrated [Bortolaia et al., 2010. Vet.Microbiol. P 379-386]. In the same study, cephalosporin resistance was not found in 20 broiler parent farms and 350 broiler farms in 2007, although selective methods were used. Regarding E. coli from pigs, the occurrence of
ampicillin, chloramphenicol, sulfonamide, streptomycin and spectinomycin resistance increased significantly from 2008 to 2009. For ampicillin, this was part of an increasing trend from 8% in 2000 to 26% in 2009, probably related to an increasing consumption in the same period (Figure). For spectinomycin, a decreasing trend was observed both in resistant E. coli and consumption since 2004, while both resistance and consumption increased in 2009. Since 2000, the trends in occurrence of sulfonamide resistant E. coli have been similar to the trend in spectinomycin resistant E.
coli, probably as a consequence of co-selection. For
tetracycline, an increasing trend (p=0.058) was seen for tetracycline resistance from 2008 to 2009, as part of
a significant increasing trend from 24% in 2000 to 35% in 2009; tetracycline consumption in the pig production has been increasing since 2002, in particular from 2005 to 2007. In 2009 a supplementary investigation of cephalosporin resistant E. coli from pigs was performed by use of a selective enrichment method (see focus area).
In cattle, no statistically significant changes in the level of resistance were observed from 2008–2009. (Table 52 in Appendix 1, Figure 34, see also DANMAP 2007). Resistance to tetracycline, ampicillin, and sulfonamide has been decreasing since 2004, with a non-significant increase in ampicillin resistance in 2009. Concurrently, the use of the corresponding antimicrobial groups in calves has been decreasing until 2008. In cows, the use of tetracyclines, sulfonamide, streptomycin and aminopenicillin increased during the same period.
Escherichia coli from food
For Danish meats, E. coli were isolated from 53% (106/200) of the pork samples, 21% (32/156) of the beef samples, and 55% (143/259) of the broiler samples. For imported meats, E. coli were isolated from 33% (65/196) of the pork samples, 40% (39/98)
of the beef samples and 87% (222/254) of the broiler samples. All E. coli isolated from meat were susceptibility tested.
Table 53 in Appendix 1 present the MIC distributions and occurrence of antimicrobial resistance in E. coli isolates collected from broiler meat, pork and beef sampled at wholesale and retail outlets in 2009. Compared to Danish broiler meat, the level of resistance was significantly higher for 14 of the tested antimicrobial agents in E. coli from imported broiler meat, including tetracycline, chloramphenicol, ampicillin, cefoxitime, ceftiofur, colistin, sulfonamide, trimethoprim, neomycin, spectinomycin, streptomycin, ciprofloxacin and nalidixic acid (Table 21).
Cephalosporin resistance was observed among E.
coli from imported broiler meat (3.6%) where also
the highest prevalence of fluoroquinolone resistance was found (41% ciprofloxacin resistance); in Danish broiler meat, no cephalosporin resistance and 4.1% ciprofloxacin resistance was found. In imported pork, two isolates with MIC for nalidixic acid < 32 and for ciprofloxacin > 0.06 were found. The isolates contained transferable fluoroquinolone resistance encoded by qnrB and qnrS, respectively. The occurrence of resistance in E. coli isolates obtained from imported beef was low and not statistically higher compared to isolates from Danish beef.
In E. coli from Danish pork, resistance to ampicillin (from 15% to 29%), streptomycin (28% to 42%), and sulfonamide (18% to 38%) has increased significantly from 2004 to 2009. Resistance to ceftiofur was found
in one isolate from Danish pork in 2009, and was found for the first time in Danish pork in 2008. In 2009, no statistically significant differences were observed by comparison of resistance in E. coli isolates obtained from imported pork and Danish pork. However, the resistance to fluoroquinolone remained low in Danish pork, probably due to the low fluoroquinolone consumption in Danish pigs since 2002; in imported pork, 10% of the E. coli isolates were resistant to fluoroquinolone in 2009.
In 2009, a supplementary investigation of cephalosporin resistant E. coli from meat was performed by use of a selective enrichment method (see focus area).
Comparison of resistance in Escherichia coli from animals and food
Data on the occurrence of resistance in food animals and Danish foods are presented in Table Icoli5. For most of the tested antimicrobial agents, the level of resistance in Danish meat reflected the level of resistance in the corresponding animal species with some exceptions. The occurrence of nalidixic acid, sulfonamide and trimethoprim resistance was significantly lower in Danish broiler meat as compared to isolates from broilers. The differences in the level of resistance between broiler meat and broilers might be caused by cross contamination at the slaughter house or due to some resistant isolates being less fit to survive through the food production chain than susceptible isolates.