TITLE:
Molecular Characterization of Bacteriocinogenic, Antifungal and Probiotic Lactic Acid Bacteria Isolated from Chicken Gastrointestinal Tract
AUTHORS:
Venkatasatyanarayana Nallala, K. Jeevaratnam
KEYWORDS:
Broiler Chicken, Filamentous Fungi, Lactobacillus plantarum, Probiotic
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.9,
August
27,
2015
ABSTRACT: In this study, bacteriocinogenic Lactobacillus
plantarum isolates capable of inhibiting food- and feed-borne filamentous
fungi from the gastrointestinal tract (GIT) of broiler chicken were identified
using 16S rRNA gene sequencing and further evaluated for probiotic properties in vitro. Six potent lactobacilli were
selected from one hundred and thirteen isolates for the present study based on
their ability to inhibit both pathogenic bacteria and filamentous fungi. They
were characterized using various physiological, biochemical and molecular
methods. They were acetoin producers, homo fermentative, catalase-negative and
producing racemic lactic acid (10 - 20 mM). All the six isolates exhibited
varied sugar utilization and RAPD pattern, indicated their strain level
genotypic variation. The 16S rRNA gene sequence and multiplex PCR analysis
confirmed that these isolates were Lactobacillus
plantarum. The isolates being resistant to low pH (2.0) and bile salt
(0.6%) could survive in the gastrointestinal tract of host indicating their
potential probiotic application. The isolates were non-pathogenic (γ-hemolytic) and exhibited resistance to
antibiotics ciprofloxacin, nalidixic acid, norfloxacin, nitrofurantoin,
colistin and streptomycin. They demonstrated strong autoaggregating phenotype
ranging from 78% to 86% and showed 49% - 61% and 30% - 46% coaggregation with E. coli MTCC 728 and L. monocytogenes MTCC 657, respectively.
The percentage of hydrophobicity ranged from 16% - 33% for all the isolates
showing that surface was rather hydrophilic. They exhibited β-galactosidase activity ranging from
1036 - 1179 MU, bile salt hydrolase activity assisting to reduce serum
cholesterol and produced the anti-Listerial bacteriocin. The strong inhibitory activity of these isolates against food
spoilage molds and bacteria with probiotic properties indicates their potential
application as food preservatives.