title: Diverse Profiles of N-acyl Homoserine L-Lactones, Biofilm, Virulence Genes and Integrons in Food-Borne Aeromonas Isolates.
abstract: 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.
authors.affiliation: Food Technology Div., Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Vandan
authors.initials: V
authors.lastname: Nagar
authors.affiliation: Food Technology Div., Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Vibha
authors.initials: V
authors.lastname: Sinha
authors.affiliation: Food Technology Div., Bhabha Atomic Research Centre, Mumbai, 400 085, India.
authors.forename: Jayant R
authors.initials: JR
authors.lastname: Bandekar
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D054742:Acyl-Butyrolactones / Q000378:metabolism*; D000333:Aeromonas / Q000235:genetics* / Q000302:isolation & purification*; D018441:Biofilms; D002855:Chromatography, Thin Layer; D053938:DNA Fragmentation; D004269:DNA, Bacterial / Q000235:genetics; D005506:Food Contamination; D005516:Food Microbiology; D005798:Genes, Bacterial; D007194:India; D032023:Integrons; D053038:Quorum Sensing; D012097:Repressor Proteins / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D014774:Virulence / Q000235:genetics
chemical_list: D054742:Acyl-Butyrolactones; D004269:DNA, Bacterial; C092312:N-butyrylhomoserine lactone; C503769:N-heptanoyl-homoserine lactone; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins; D015107:4-Butyrolactone
keywords: aeromonas; biofilm; integrons; quorum sensing; virulence genes