Swine enteric colibacillosis: Current treatment avenues and future directions

Abstract

Enteric colibacillosis is a common disease in nursing and weanling pigs. It is caused by the colonization of the small intestine by enterotoxigenic strains of Escherichia coli (ETEC) that make use of specific fimbria or pili to adhere to the absorptive epithelial cells of the jejunum and ileum. Once attached, and when both the immunological systems and the gut microbiota are poorly developed, ETEC produce one or more enterotoxins that can have local and, further on, systemic effects. These enterotoxins cause fluid and electrolytes to be secreted into the intestinal lumen of animals, which results in diarrhea, dehydration, and acidosis. From the diversity of control strategies, antibiotics and zinc oxide are the ones that have contributed more significantly to mitigating post-weaning diarrhea (PWD) economic losses. However, concerns about antibiotic resistance determined the restriction on the use of critically important antimicrobials in food-producing animals and the prohibition of their use as growth promoters. As such, it is important now to begin the transition from these preventive/control measures to other, more sustainable, approaches. This review provides a quick synopsis of the currently approved and available therapies for PWD treatment while presenting an overview of novel antimicrobial strategies that are being explored for the control and treatment of this infection, including, prebiotics, probiotics, synbiotics, organic acids, bacteriophages, spray-dried plasma, antibodies, phytogenic substances, antisense oligonucleotides, and aptamers.

Swine Colibacillosis: Global Epidemiologic and Antimicrobial Scenario

“…Although, the risk of development of a pan-resistant MDR ETEC remains and may constitute a huge problem in public health. Therefore, alternative therapeutics (prebiotics, probiotics, synbiotics, organic acids, phytogenic substances, bacteriophages, specific egg yolk antibodies, lactoferrin, antisense oligonucleotides, spray-dried animal plasma, and aptamers), as well as hygienic and sanitary measurements, should be applied in pig farming [ 2 , 4 ].…”

“…The first four fimbria types are responsible for mediating adhesion in neonates, while F18 is not associated with neonatal colibacillosis; however, it is common in postweaning colibacillosis as is F4. It is also important to highlight that hemolysis is a common trait for pathogenic F4 and F18 isolates [ 4 ]. The adhesion of ETEC through fimbriae conducts the release of toxins inside the epithelial cell that promote the secretion of water and electrolytes into the intestinal lumen [ 1 , 2 , 8 ].…”

“…PWD and ED may occur separately or together either in an individual outbreak or in the same pig [ 1 ]. Within 2–3 weeks after weaning, the piglets are more susceptible to microbial infections, owing to the existence of an immature immune system associated with sow milk removal and resulting from the interruption of the nutritive intake of immunoglobulin present in the milk [ 2 , 4 ]. Therefore, this period is crucial and usually associated with the most severe form of enteric E. coli infection, manifested by sudden death or severe diarrhea [ 1 ].…”

“…As an effort to promote health and growth performance, diverse approaches have been used to prevent and treat swine colibacillosis, with antibiotics being the most commonly used strategy [ 2 , 4 ]. Consequently, due to the growing selective pressure of antibiotic use to treat these E. coli infections, the emergence of the antimicrobial resistance (AMR) phenomenon has limited treatment options for pig producers and an increased public health concern because of the potential transfer of AMR genetic determinants directly by contact and indirectly into the food chain, water, and manure, among others [ 1 , 5 ].…”

Assessing the Feasibility of a Two-Cohort Design to Assess the Potential of Homeopathic Medicinal Products to Reduce Antimicrobial Resistance in Turkeys (The HOMAMR Project)—Study Protocol

“…In pigs, promising alternatives for prevention as well as treatment of infection are pro-and pre-biotics, organic compounds such as short-and medium-chain fatty acids, phytogenic substances, bacteriophages, spray-dried plasma, and homeopathy. 8,14,37,38 In chickens, possible alternatives are egg yolk antibodies, proand pre-biotics, antimicrobial peptides such as bacteriocins, β-defensins, protegrins, insect defensins, and homeopathy. [16][17][18][19][20][21]39 In cows, alternative treatment options are phytogenic substances, probiotics, bacteriocins, bacteriophages, stem cells, minerals, trace elements, vitamins, short-chain fatty acids and microbial lipopolysaccharide, and homeopathy.…”