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Diverse Profiles of N‐acyl Homoserine l ‐Lactones, Biofilm, Virulence Genes and Integrons in Food‐Borne Aeromonas Isolates
Author(s) -
Nagar Vandan,
Sinha Vibha,
Bandekar Jayant R.
Publication year - 2015
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12949
Subject(s) - homoserine , aeromonas , microbiology and biotechnology , virulence , biology , biofilm , lactone , bacteria , enterotoxin , quorum sensing , gene , escherichia coli , biochemistry , genetics
Aeromonas are regarded as opportunistic as well as primary pathogens of humans and fish, and are associated with gastroenteritis and septicemia in humans. Production of N‐acyl‐homoserine lactone (AHL) signal molecules and biofilm was determined in 22 Aeromonas isolates, from different food products in India, using thin‐layer chromatography (TLC) analysis and microtiter‐plate assay, respectively. Overall, highly heterogeneous patterns of AHL production were observed, with the production of N‐butanoyl homoserine lactone (C4‐HSL) and N‐hexanoyl homoserine lactone (C6‐HSL) by the majority (81.8%) of Aeromonas food isolates. Moreover, putative N‐pentanoyl homoserine lactone (C5‐HSL), N‐heptanoyl homoserine lactone (C7‐HSL), and N‐octanoyl homoserine lactone (C8‐HSL) were produced by 72.7%, 27.3%, and 9.1% of isolates, respectively. This is the 1st report of production of C7‐HSL by Aeromonas species. Aeromonas food isolates were highly variable in their biofilm forming abilities with majority of them as weak biofilm producers in 2 different media, TSB and M9 minimal medium supplemented with 0.4% glucose. The genes encoding for putative virulence factors, glycerophospholipid cholesterol acyltransferase ( gcat ), heat‐labile cytotonic enterotoxin ( alt ), heat‐stable cytotonic enterotoxin ( ast ), serine protease ( ser ), polar flagella ( fla ), and lateral flagella ( lafA ) were present in 95.5%, 59.1%, 22.7%, 81.8%, 77.3%, and 22.7% of the strains, respectively. Class 1 integrons (100 to 3000 bp) were found in 68.2% of food isolates; whereas, 50% isolates contained class 2 integrons (150 to 1600 bp). This study provides a baseline data on the diversity of AHLs, biofilm forming ability and presence of virulence genes and integrons in Aeromonas food isolates from India.