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Titolo:
Quantitative molecular detection of Salmonella typhimurium in soil and demonstration of persistence of an active but non-culturable population
Autore:
Marsh, P; Morris, NZ; Wellington, EMH;
Indirizzi:
Univ Warwick, Dept Biol Sci, Coventry CV4 7AL, W Midlands, England Univ Warwick Coventry W Midlands England CV4 7AL 7AL, W Midlands, England
Titolo Testata:
FEMS MICROBIOLOGY ECOLOGY
fascicolo: 4, volume: 27, anno: 1998,
pagine: 351 - 363
SICI:
0168-6496(199812)27:4<351:QMDOST>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
POLYMERASE CHAIN-REACTION; PSEUDOMONAS-FLUORESCENS; STRESS RESISTANCE; ESCHERICHIA-COLI; NONSTERILE SOIL; PLASMID DNA; BACTERIA; EXTRACTION; SURVIVAL; WATER;
Keywords:
quantitative polymerase chain reaction; active staining; Salmonella typhimurium LT2; soil; non-culturable;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Wellington, EMH Univ Warwick, Dept Biol Sci, Coventry CV4 7AL, W Midlands,England Univ Warwick Coventry W Midlands England CV4 7AL England
Citazione:
P. Marsh et al., "Quantitative molecular detection of Salmonella typhimurium in soil and demonstration of persistence of an active but non-culturable population", FEMS MIC EC, 27(4), 1998, pp. 351-363

Abstract

Several methods were used to study survival of Salmonella typhimurium LT2 in sail. An ion exchange resin-based extraction method was used to concentrate biomass from soil, from which DNA was extracted in order to quantify a Salmonella-specific sequence by a quantitative polymerase chain reaction (QPCR). S. typhimurium LT2 was detected at a minimum density of 10(3) cells g(-1) in non-sterile soil, and the method proved to be specific for this organism in microcosm experiments. Non-sterile soil microcosms were inoculatedwith S. typhimurium LT2 at 10(7) cfu g(-1) dry soil and survival monitoredat three matric potentials. Viable counts on XLD indicated a rapid declinein cell density over 54 days, whereas direct counts of active cells using the respiration-sensitive dye 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) remained relatively constant. XLD did not underestimate culturable cells in comparison to non-selective agar. QPCR revealed that the number of salmonella targets (H-li) remained constant up to day 13. After that time, a decrease occurred, corresponding to that of the plate counts, due to an increase in resistance of the cells to lysis, as incorporation of a lysozyme stepinto the DNA extraction method allowed more efficient DNA extraction. Thisresulted in a constant QPCR signal over 54 days which correlated with direct, active cell counts. QPCR showed H-li was present at levels only slightly lower than those at day 0. There was no difference in survival between the three different moisture regimes. Direct CTC counts of S, typhimurium LT2in the soil microcosms confirmed that intact cells were present in a metabolising state after 54 days in non-sterile soil, indicating a significant proportion of uncultured but active cells. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 12/07/20 alle ore 12:34:09