Classical symptoms of OD (Oedema disease), oedema of eyelids.
Table 2-Frequent resistance to several ATB including ones used for the control of E. coli.
Antimicrobial
Gentamicin Neomycin Penicillin
EU. There is a big pressure to decrease usage of both fluoroquinolones (enrofloxacin) and colistin for the mass medication post weaning. They are included in category B = “Restrict” in a new, four-group categorisation, which corresponds to Category 2 in the first Antimicrobial Advice Ad Hoc Expert Group (AMEG) report. Much attention has been paid recently mainly to colistin, due to studies performed in China and subsequently as well in EU countries, describing a transmissible, plasmid-mediated resistance gene in commensal E. coli, (mostly mcr-1, mcr-4 and mcr-5). This fact led, like it was mentioned, to the re-assessment of the low- risk use of colistin in animals to the reclassification of colistin to Category B of the proposed European classification system, which includes medicines reserved for treatment of infections in humans, for which no effective alternative treatments exist. Another fact, which is necessary to consider, is that STEC strains are frequently multi-resistant to antibiotics commonly used during the nursery period, including the ones which are used for treatment of post weaning diarrhoea and OD. A recently published study evaluating sensitivity profile of STEC strains detected frequent resistance to the aminoglycoside group (Gentamicin, Neomycin,Clindamycin) among others, which is considered as possible alternative for colistin (Table 2).
Effect of vaccination on ZnO consumption Currently, ZnO together with colistin are probably the most frequently used compounds during the post weaning period to control E. coli diarrhoea and losses caused by OD. Several studies and reports showing that zinc oxide does contribute to antimicrobial resistance, as the high levels of zinc oxide can increase the proportion of multi-resistant E. coli as well, increase the persistence and prevalence of methicillin- resistant Staphylococcus. Therapeutic usage of ZnO (high levels of zinc oxide, about 2,000, 2,500, 3,000 ppm, whereas
the requirement for zinc to the pig is 150 ppm) will be banned based on the negative benefit-risk balance from July 2022 onwards. Therefore, other effective tools are needed. A recently published study from Spain proved significant positive effect of vaccination on zootechnical parameters (ADG- Average Daily Gain and ADFI- Average Daily Feed Intake) in the group of piglets vaccinated against OD. Vaccination significantly reduced pig losses and improved ADG and ADFI, particularly when ZnO was removed from the feed.
Sulfadimethoxine Tetracycline Tiamulin Ampicillin
Clindamycin Enrofloxacin Florfenicol
Number of susceptible STEC isolates 5/16 4/16 0/16 2/16 0/16 0/16 9/16 0/16 3/16 6/16
Adopted from Hewitt et al., 2020.
Other possibilities for control of OD Besides vaccination, other possible management strategies, such us restriction of feed intake, reduction of crude protein content, digestible energy and high fibre diets have been also reported as effective in the control of E. coli infection outbreaks in the field and can be used for OD control with variable effects. However, these measures have obvious negative effects on the performance of the animals, limiting growth potential of the current fast-growing genetics and compromising the economy of production.
Reducing mass medication on farms Early vaccination against OD on 4th
day of life of piglets was
proven to be a successful tool to reduce the mass medication with colistin and ZnO on farms. It can be concluded that re- placing antimicrobials and ZnO demands is a multifactorial approach and vaccination against infections caused by fre- quent post weaning pathogens, like Shiga toxin producing E. coli strains is one of the most promising and effective tool.
Contact the author
daniel.sperling@ceva.com for references. ▶ ANTIBIOTIC REDUCTION | DECEMBER 2021 65
PHOTO: CEVA SANTE ANIMALE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96
