title: Biofilm-Forming Abilities of Listeria monocytogenes Serotypes Isolated from Different Sources.
abstract: A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26%) strains as weak, 27 (27.55%) strains as moderate, and 9 (9.18%) strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015) was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 103 cells/cm2, 33±26× 103 cells/cm2, 5±3× 103 cells/cm2, respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI) analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.
authors.affiliation: ICAR Research Complex for Goa, Old Goa 403 402, India.
authors.forename: Swapnil P
authors.initials: SP
authors.lastname: Doijad
authors.affiliation: ICAR Research Complex for Goa, Old Goa 403 402, India; National Institute of Biotic Stress Management, IGKV Campus, Krishak Nagar, Raipur, Chhattisgarh, 492012, India.
authors.forename: Sukhadeo B
authors.initials: SB
authors.lastname: Barbuddhe
authors.affiliation: Department of Microbiology, Goa University, Taleigaon Plateau, Goa 403 206, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Garg
authors.affiliation: ICAR Research Complex for Goa, Old Goa 403 402, India.
authors.forename: Krupali V
authors.initials: KV
authors.lastname: Poharkar
authors.affiliation: Department of Microbiology and Animal Biotechnology, Nagpur Veterinary College, Maharashtra Animal and Fishery Sciences University, Nagpur 440006, India.
authors.forename: Dewanand R
authors.initials: DR
authors.lastname: Kalorey
authors.affiliation: Department of Microbiology and Animal Biotechnology, Nagpur Veterinary College, Maharashtra Animal and Fishery Sciences University, Nagpur 440006, India.
authors.forename: Nitin V
authors.initials: NV
authors.lastname: Kurkure
authors.affiliation: Division of Veterinary Public Health, Indian Veterinary Research Institute, Izatnagar, 243122, India.
authors.forename: Deepak B
authors.initials: DB
authors.lastname: Rawool
authors.affiliation: Institute of Medical Microbiology, Justus-Liebig University, 35392 Giessen, Germany.
authors.forename: Trinad
authors.initials: T
authors.lastname: Chakraborty
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D005227:Fatty Acids / Q000378:metabolism; D008089:Listeria monocytogenes / Q000145:classification / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D065288:Serogroup
chemical_list: D005227:Fatty Acids