title: In vitro study on the effect of doxycycline on the microbial activity of soil determined by redox-potential measuring system.
abstract: The potential effect of doxycycline on the microbial activity was investigated in three types of soil. Soil samples were spiked with doxycycline, incubated at 25°C and tested at 0, 2, 4 and 6 days after treatment. The microbiological activity of the soil was characterized by the viable count determined by plate pouring and by the time necessary to reach a defined rate of the redox-potential decrease termed as time to detection (TTD).The viable count of the samples was not changed during the storage. The TTD values, however exhibited a significant increase in the 0.2-1.6 mg/kg doxycycline concentration range compared to the untreated samples indicating concentration-dependent inhibitory effect on microbial activity. The potency of the effect was different in the 3 soil types. To describe the combined effect of the doxycycline concentration and time on the biological activity of one type of soil a mathematical model was constructed and applied.The change of microbial metabolic rate could be measured also without (detectable) change of microbial count when the traditional microbiological methods are not applicable. The applied new redox potential measurement-based method is a simple and useful procedure for the examination of microbial activity of soil and its potential inhibition by antibiotics.
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Szakmár
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Olivér
authors.initials: O
authors.lastname: Reichart
authors.affiliation: Gedeon Richter Plc. Debrecen Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Szatmári
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Orsolya
authors.initials: O
authors.lastname: Erdősi
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Szili
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Noémi
authors.initials: N
authors.lastname: László
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Székely Körmöczy
authors.affiliation: Szent István University Department of Food Hygiene, Faculty of Veterinary Science Budapest Hungary.
authors.forename: Péter
authors.initials: P
authors.lastname: Laczay
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D015169:Colony Count, Microbial; D004318:Doxycycline / Q000494:pharmacology*; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D012987:Soil; D012989:Soil Pollutants; D004318:Doxycycline
keywords: doxycycline; microbial activity; redox potential; soil