Table 8.
Summary of reviewed articles comparing antimicrobial resistance between organic and conventional livestock production
| Animal species | Number of articles | Number of articles with data from <10 conventional (organic) sampling locations | Number of times bacteria addressed in all articles | Sampling location bacteria | Higher single drug resistance (number of bacteria–drug combinations over all studies) 1 | Higher multidrug resistance (number of multidrug-resistant bacteria over all studies) 2 |
|---|---|---|---|---|---|---|
| Dairy cattle | 20 | 4 (7) Not mentioned 3 (3) | Bacteria 1, Campylobacter 1, Campylobacter spp. 2, coagulase-negative staphylococci 2, ESBL-producing Escherichia coli 1, E. coli 4, E. coli O157 1, genes (tet(O), tet(W), sul (I), sul(II)) 1, nonaureus staphylococcus spp. 1, Salmonella spp. 1, Shiga Toxigenic E. coli 1, Staphylococcus 1, Staphylococcus aureus 7, Streptococcus uberis 1, Streptococcus dysgalactiae 1 | Farm 20, retail 1 | O>C 5 C>O 26 | O>C 0 C>O 2 |
| Beef cattle | 2 | 0 (0) Not mentioned 2 (2) | Enterobacteriaceae 1, E. coli 1, Listeria monocytogenes 1, mesophillic aerobic bacteria 1, S. aureus 1 | Retail 4 | O>C 2 C>O 6 | O>C 0 C>O 0 |
| Pigs | 5 | 2 (2) Not mentioned 2 (3) | Campylobacter spp. 1, Enterobacteriaceae 1, Enterococcus faecium 1, Enterococcus spp. 1, E. coli 3, mesophillic aerobic bacteria 1, vancomycin-resistant E. faecium 1 | Farm 4, retail 2 | O>C 0 C>O 4 | O>C 0 C>O 1 |
| Broilers | 20 | 10 (7) Not mentioned 8 (9) | Campylobacter spp. 6, Enterobacteriaceae 2, E. faecium 2, Enterococcus faecalis 1, Enterococcus spp. 1, ESBL 1, ESBL-producing bacteria 1, E. coli 4, E. coli carrying bla(CMY-2) 1, E. coli carrying bla(CTX-M) 1, L. monocytogenes 1, mesophilic aerobic bacteria 1, quinolone-resistant determining regions in E. coli 1, Salmonella 1, Salmonella spp. carrying bla(CMY-2) 1, Salmonella Kentucky 1, Salmonella spp. 4, S. aureus 1, vancomycin-resistant Enterococci 1, vancomycin-resistant E. faecium 1 | Farm 5, processing 3, retail 20 | O>C 5 C>O 50 | O>C 0 C>O 8 |
| Laying hens | 3 | 0 (0) Not mentioned 1 (1) | Campylobacter coli 1, Campylobacter jejuni 1, Enterococcus spp. 1, E. coli 2, Listeria spp. 1 | Farm 5, retail 1 | O>C 3 C>O 13 | O>C 0 C>O 2 |
1
O>C: over all bacteria–drug combinations analysed in the articles, number of times bacteria in organic livestock system were more resistant to a specific drug than bacteria in conventional livestock system. C>O vice versa.
2
O>C: number of times bacteria in organic livestock system showed more multidrug resistance than in conventional livestock system. C>O vice versa.