Intestinal infection caused by Escherichia coli is an important disease resulting in significant economic losses. Knowledge about epidemiology, diagnosis and treatment, and control strategies are of fundamental importance to successfully tackle this disease.
Escherichia coli is a Gram-negative bacterium causing neonatal diarrhoea (ND; Figure 1), post-weaning diarrhoea (PWD; Figure 2) and post-weaning oedema disease. These Colibacillosis infections are important causes of death in suckling and weaned pigs worldwide.
Challenges to Colibacillosis treatment and control
In the EU, restrictions are in place on the use of antimicrobial products. Based on the implementation of the EU Antibiotics Categorization System, from January 2023 the use of several antibiotics, e.g., colistin and enrofloxacin in Category B which are highly effective against E. coli, will be restricted.
The use of zinc oxide as a therapeutic drug (at dosage levels of 2,000 - 3,000 ppm) will be banned for medicinal use from June 2022. As a consequence, a change to antibiotics which are not considered critically important for human medicine use is needed. These include antibiotics listed under Category C and D in the EU Categorization System.
Vaccines which are highly effective against all E. coli strains causing ND, PWD and oedema disease are not currently available. The vaccines that are in use have a narrow spectrum covering only some of the E. coli pathotypes and virotypes which can be present on affected farms.
Antibiotics used to treat enteric colibacillosis must be chosen for their ability to achieve therapeutic concentrations in the intestinal lumen. The antimicrobial susceptibility of the E. coli strains is fundamental for successful therapy. Outbreaks of E. coli intestinal infection require quick action and use of the most effective antibiotics.
Apravet® and Parofor® - the colibacillosis treatment options of choice
Apravet® (apramycin) and Parofor® (paromomycin) concentrate in the small and large intestine of pigs after feed and water administration.
Antimicrobial susceptibility testing on E. coli strains is done in many countries. Apramycin minimum inhibitory concentration (MIC) test results from European E. coli strains are shown in relation to apramycin intestine concentrations achieved at treatment dosage after feed medication (Figure 3).
The apramycin concentration in the small intestine exceeds the MIC90 value of 90% of the tested EU E. coli strains. These results indicate very high sensitivity of the strains, predicting high efficacy of Apravet® in the case of its metaphylactic and therapeutic use.
The paromomycin MIC results from European E. coli strains are shown in relation to the paromomycin concentrations achieved in the small intestine at treatment dosage after water medication (Figure 4).
Paromomycin concentrations in the small intestine achieved at the lowest registered dose (25 mg/kg body weight) are high and above the MIC90 of 88% of the tested EU E. coli strains.
Higher paromomycin intestinal concentrations are expected at the highest registered dose (40 mg/kg body weight) for Parofor®. Estimated intestinal concentrations are about 1,100 µg/g in the small and large intestine, which are all above the MICs determined for paromomycin.
Apravet® and Parofor® are ideal options for antibiotic metaphylaxis and therapy in cases of enteric colibacillosis outbreaks. Both are first-choice treatment alternatives for antimicrobials which are restricted or will be banned in the future.
Apravet®: the first-choice product for metaphylaxis and treatment of E. coli infections post-weaning applied either in the feed or via the drinking water.
Parofor®: the first-choice product for E. coli neonatal diarrhoea treatment.
