title: Comparison of microbiological and physicochemical methods for enumeration of microorganisms.
abstract: Determination of the number of cultured bacteria is essential for scientific and industrial practice. A spread plate technique is the most common and accurate method for counting of microorganisms. However, time consuming incubation does not allow for a quick estimation of the number of bacteria in a growing culture. In the present study, the results of photometric measurements: direct optical density method (OD at 585 nm), UV absorbance at 260 and/or 280 nm of separated and lysed bacteria by sodium hydroxide and surfactant with the spread plate technique were compared. The linear regression model for bacterial strains Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli was used to compare these three methods. The UV measurement method enabled determination of the number of bacteria with similar precision. The procedure for solubilized bacteria UV measurement is robust, and is not influenced by dispersions in the original culture medium.
authors.affiliation: Laboratory of Biomedical Chemistry "Neolek", Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Bożena
authors.initials: B
authors.lastname: Szermer-Olearnik
authors.affiliation: Laboratory of Biomedical Chemistry "Neolek", Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland; Laboratory of Virology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Sochocka
authors.affiliation: Laboratory of Virology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Zwolińska
authors.affiliation: Laboratory of Biomedical Chemistry "Neolek", Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Jarosław
authors.initials: J
authors.lastname: Ciekot
authors.affiliation: Laboratory of Medical Microbiology, Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Czarny
authors.affiliation: Laboratory of Biomedical Chemistry "Neolek", Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Szydzik
authors.affiliation: Laboratory of Biomedical Chemistry "Neolek", Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
authors.forename: Konrad
authors.initials: K
authors.lastname: Kowalski
authors.affiliation: Laboratory of Biomedical Chemistry "Neolek", Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland; Jan Długosz University in Częstochowa, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Boratyński
mesh_terms: D001431:Bacteriological Techniques; D015169:Colony Count, Microbial / Q000379:methods*; D004926:Escherichia coli / Q000254:growth & development*; D010783:Photometry / Q000379:methods*; D011550:Pseudomonas aeruginosa / Q000254:growth & development*; D013211:Staphylococcus aureus / Q000254:growth & development*; D014466:Ultraviolet Rays