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Antimicrobial activity of Enterococcus faecium ef 55 against Salmonella enteritidis in chicks
Mikulás Levkut1, Juraj Pistl, Andrea Lauková'
1Department of Pathological Anatomy, University of Veterinary Medicine, Komenského 73, 041 81 Kosice, Slovak Republic. levkut@uvm.sk
Insights
Enterococcus faecium EF 55 administration significantly reduced Salmonella Enteritidis PT4 colonization in chicks. This probiotic demonstrated antimicrobial effects, lowering Salmonella counts in feces and preventing liver invasion without impacting lymphocyte subpopulations.
Area of Science:
- Animal Science
- Microbiology
- Immunology
Background:
- Salmonella enterica serovar Enteritidis phage type 4 (SE PT4) poses a significant threat to poultry health and food safety.
- Probiotics, such as Enterococcus faecium, are explored for their potential to mitigate bacterial infections in livestock.
- Understanding the efficacy of specific probiotic strains against targeted pathogens is crucial for developing effective control strategies.
Purpose of the Study:
- To evaluate the protective effect of Enterococcus faecium EF 55 against Salmonella Enteritidis PT4 infection in 1-day-old chicks.
- To assess the colonization of E. faecium EF 55 in the chick's digestive tract and its impact on SE PT4 shedding.
- To investigate the influence of E. faecium EF 55 on SE PT4 translocation to internal organs and its effect on host immune parameters.
Main Methods:
- One-day-old chicks were administered Enterococcus faecium EF 55 daily for 7 days.
- Chicks were orally inoculated with Salmonella Enteritidis PT4 on day 8.
- Salmonella counts in feces and liver, E. faecium EF 55 colonization, and lymphocyte subpopulations were monitored over 21 days using culture and PCR methods.
Main Results:
- Enterococcus faecium EF 55 successfully colonized the chicks' digestive tract.
- SE PT4 counts in feces and caecum were significantly reduced in chicks treated with EF 55 compared to controls.
- Liver colonization by SE PT4 was significantly lower in the EF 55 treated group, with Salmonella isolated for shorter periods.
Conclusions:
- Enterococcus faecium EF 55 exhibits a significant antimicrobial effect against Salmonella Enteritidis PT4 in poultry.
- Probiotic administration of EF 55 effectively reduces SE PT4 shedding and systemic invasion.
- E. faecium EF 55 shows promise as a preventative measure against Salmonella infections in chickens without adverse effects on key lymphocyte populations.
Abstract:
The protective effect of Enterococcus faecium EF 55 against Salmonella enterica serovar Enteritidis phage type 4 (SE PT4) was studied in 1-day-old chicks. The EF 55 strain (isolated and characterised by the authors earlier) was applied daily (1.10(9) CFU/0.2 ml PBS) for 7 days. Oral inoculation of the SE PT4 strain was performed on day 8 in a single dose of 5.10(8) CFU/0.2 ml PBS. The experiment lasted for 21 days. Samples were collected on day 1 of the experiment to verify the absence of Salmonella, on day 8 to check colonisation of EF 55 and immunological status in experimental birds, and on days 2, 4, 6, 8 and 14 after SE PT4 infection of chicks. Strain EF 55 sufficiently colonised the digestive tract of chicks after 7 days of application. The highest numbers of EF 55 in the faeces of chicks were observed before SE infection and persisted to day 6 post infection (p.i.) in both the EF and EF+SE groups. PCR confirmed the identity of the EF 55 strain. The counts of SE PT4 strain in faeces of the EF+SE group were significantly reduced in comparison to those in the SE group on days 2 and 14 p.i. (P < 0.01). The significant reduction of salmonellae in the caecum was recorded at the end of the experiment (day 14 p.i.) in the EF+SE group in comparison to the SE group (P < 0.01). At day 4 p.i., colonies of S. Enteritidis PT4 were found in the liver of chicks of the SE group in a higher concentration than in chicks of the EF+SE group (P < 0.001). Salmonellae were isolated from the liver until days 8 and 6 p.i. in the SE and EF+SE groups, respectively. The mean values of actual lymphocyte subpopulations in the blood and the relative percentage of caecal intraepithelial lymphocyte subpopulations (CD4, CD8, CD44, TCR, MHC II and IgM) were not influenced at a statistically significant level by the application of the EF 55 and/or the SE PT4 strain. The results demonstrate the antimicrobial effect of E. faecium EF 55 against S. Enteritidis PT4.
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