Prevention and Treatment of Salmonella and E. Coli in Poultry

Posted by maria on November 21st, 2020

The United States Department of Agriculture (USDA) recently reported that global chicken meat production is expected to increase by 2 percent in 2021 to 102.9 million tonnes. With the rising demand for chicken meat and eggs, the poultry industry faces a tough challenge – how to control bacterial diseases among the flocks. The most common infections associated with poultry are Salmonella and E. Coli. In the United States, the prevalence of Salmonellosis infection among chicken flocks is around 75-90% whereas, for E. Coli, it is around 90-95%. The annual economic losses in the country resulting from Salmonella infections is more than .58 billion. While there is no consolidated study to accurately estimate the prevalence of Salmonella and E. Coli infections in poultry stock in India, sporadic studies have found significant presence. A study conducted in a Tamil Nadu city in 2017 found prevalence of 33% Salmonella in raw chicken meat. Another study conducted in two northern Indian towns in 2012 found Salmonella in about 5% eggs and E. Coli strains in about 28% of eggs examined.

Amid the rising concerns of rampant Salmonella and E. Coli infections and emergence of their antibiotic resistant strains, the poultry industry is searching for viable alternatives to combat these bacterial infections to keep animals and humans safe & to mitigate the AMR risk to improve food safety.

The Threat of Salmonella and E. Coli to Poultry

Salmonellosis is a major cause of infection in poultry that stems from bacteria belonging to the Salmonella genus. There are different types of species and each results in a specific disease. For example, Arizonosis occurring among chicks is a septicemic disease caused by Salmonella enterica; Pullorum Disease (PD) also known by the name Bacillary White Diarrhoea which causes a high mortality rate in young chickens (2-3 weeks), results from infection with S. Pullorum. Some other examples include, Fowl Typhoid (FT) which again is an acute septicemic disease caused by S. Gallinarum and affects adults and growing chickens. Paratyphoid (PT) infection is a common occurrence among chickens usually caused by S. Enteritidis and S. Typhimurium.

On the other hand, there are different strains of Escherichia Coli or E. Coli present in the digestive tracts of chickens. Even though most of these strains are harmless, there are certain strains that can be grouped into the APEC or Avian Pathogenic E. Coli which can be a major cause of infections among chicken. The APEC strains causes colibacillosis which is a major cause of mortality and morbidity in poultry.

It’s hard to overlook the economic impact of these infections. These infections can result in huge economic losses to poultry farms. On top of that, they can be a big hindrance to international trade as there is increased risk of transmitting infections to humans.

The Growing Concern of Antibiotic Resistance

For the prevention of E-coli & Salmonella, poultry farmers commonly use antibiotics on a routine basis. However, the excessive and indiscriminate use of antibiotics has led to the development of antibiotic resistance (AR) strains in pathogens This has not only led to treatment failures but economic losses and transmission of antibiotic resistant strains to humans. 

Usually, antibiotics eliminate susceptible bacterial strains and leave behind those strains that can resist the drug. The resistant strains further multiply and transfer their resistant genes to other bacteria. These resistant bacteria can then be transferred from poultry to humans through consumption of poultry products or handling. 

A study conducted to determine the antibiotic susceptibility of 156 pathogenic E. Coli strains showed that every strain was resistant to at least 2 antibiotics and more than 66% of the strains were resistant to at least 7 antibiotics.

Another major disadvantage of antibiotics is that they kill the good bacteria inside the gut as well that are important for healthy development of poultry which can prevent other fungal, viral and bacterial infections.

Bacteriophages can address the Problem                                                                                              

Countries like Sweden, the United Kingdom, the Netherlands, Denmark and other European nations have already banned the use of growth promoting antibiotics in animals. Indian government has recently banned the use of last resort antibiotic colistin in food animals to check the growing menace of drug resistant superbugs.

As an alternative to cut down on the usage of antibiotics, bacteriophages or simply ‘phages’ have turned out to be a safe bet for poultry farmers. Bacteriophages happen to be viruses that attach to the infectious bacteria, replicate inside it to create more no. of new phages, due to increase in population of new phages inside the bacteria, there is outburst of bacterial cell wall to release the new phages into the environment, this process is called amplification, that allows phages to effectively destroy the targeted bacteria. The best part is that apart fromdestroying the targeted bacteria, it doesn’t have any negative impact on other cells of animals or humans.  

Phage therapy is emerging as a growing trend to combat antibiotic-resistant infections. At Proteon Pharmaceuticals, we are working to revolutionise the approach to eliminate pathogenic bacteria through controlled and sustainable ways without causing any harm to the birds and humans. Our phage-based poultry feed additives BAFASAL+G and BAFACOL helps to control pathogenic Salmonella and Avian Pathogenic E. Coli respectively across poultry species and breeds. Phage therapy helps reduce mortality rate, improves production performance, feed conversion ratio and reduces the unnecessary usage of antibiotics. It is the need of the hour to popularize and promote the growth of such sustainable solutions to ensure optimal health of poultry flocks and reduce the risk of infections in humans. Poultry farmers also need to be educated about the ill-considered use of antibiotics along with better control practises and proper disease management to tackle the rising prevalence of bacterial diseases in poultry.