Screening of lactic acid bacteria isolated from chicken ceca for In vitro growth inhibition of Salmonella enteritica serovar enteritidis

Abstract

Salmonellosis in humans caused by consumption of contaminated poultry products with Salmonella enteritica serovar enteritidis (S. enteritidis) is still a public health problem. Many efforts have been developed to eradicate or reduce Salmonella loads in poultry industry. Use of normal microbiota (e.g., Lactic Acid Bacteria (LAB)) against the pathogen is an alternative of antibiotics used and is under extensive investigations. Therefore, the objective of this study was to screen and identify the LAB strain showing the greatest growth inhibition against S. enteritidis. LAB were isolated from chicken ceca of five clinically healthy broilers (age, 42-50 days). The bacteria were grown in MRS broth and on the plate with selective media Rogosa agar. For screening of the inhibitory effects of the isolated LAB against S. enteritidis, we used disc diffusion and agar well diffusion methods. In this study, 56 isolates exhibited inhibitory effect against S. enteritidis but only thirteen isolates producing a clear zone as large as 19 mm or greater were selected for acid tolerance test. In this test, three isolates did survive at pH 2.5 for 18 h but only 1 isolate was subjected for evaluation by coculture with S. enteritidis and for 16S rDNA sequencing. This isolate was able to grow in the coculture medium and at the same time, inhibited the growth S. enteritidis. This isolate was identified as Lactobacillus salivarius TP4.2-2. © Medwell Journals, 2011.