title: An investigation of the presence of ultramicrocells in natural mineral water.
abstract: The presence of 'ultramicrocells' in natural mineral water, capable of passing through a 0.2 micron filter, has been demonstrated. Filters allowing the greatest proportion of viable (culturable) cells to pass ranked in the order, 0.4 micron polycarbonate (5.02%) > 0.2 micron polycarbonate (0.02%) > or = 0.45 micron cellulose nitrate (0.02%) > 0.2 micron cellulose acetate (< 0.002%). Following incubation for 4 d at 22 degrees C, viable counts in filtered mineral water increased from < 2-8.7 x 10(2) cfu ml-1(-2).8 x 10(4)-1.9 x 10(6) cfu ml-1. Successive filtration/incubation cycles of mineral water increased the proportion of cells passing through a 0.2 micron cellulose acetate filter from < 0.003% to 0.11% and 0.69%, suggesting selection for 'ultramicrocells'. Cells isolated from this process and grown on liquid R2A medium were thin, Gram-negative rods, of 0.15-0.40 micron wide and 0.50-6.20 microns long. Membrane filtration techniques used for pathogen detection in mineral waters will not retain all the cells present. If pathogens are able to form ultramicrocells, these may go undetected.
authors.affiliation: School of Biological Sciences, University of Surrey, Guildford, UK.
authors.forename: C R
authors.initials: CR
authors.lastname: Jones
authors.forename: A H
authors.initials: AH
authors.lastname: Chamberlain
authors.forename: M R
authors.initials: MR
authors.lastname: Adams
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives; D003101:Collodion; D015169:Colony Count, Microbial; D006090:Gram-Negative Bacteria / Q000254:growth & development / Q000302:isolation & purification*; D008851:Micropore Filters; D008854:Microscopy, Electron; D008900:Mineral Waters / Q000382:microbiology*; D011076:Polycarboxylate Cement
chemical_list: D008900:Mineral Waters; D011076:Polycarboxylate Cement; C005506:polycarbonate; C005062:acetylcellulose; D002482:Cellulose; D003101:Collodion