title: Application of microbial assay for risk assessment biotest in evaluation of toxicity of human and veterinary antibiotics.
abstract: The microbial assay for risk assessment (MARA) is a multispecies, growth inhibition microplate toxicity test with 11 microorganisms individually lyophilized in microplate wells. The microbial species representing wide diversity, generated 11 microbial toxic concentration (MTC) values were obtained giving a unique "toxic fingerprint" profile of the test sample. The toxicity of 14 antibiotics was evaluated with the MARA test. The fingerprints for each group of antibiotics differ, indicating a particular toxic profile. Tetracyclines were the most toxic antibacterials with the minimum MTC value of 3.6 μg L(-1). In the group of tetracyclines the order of the three most sensitive microbial strains was the same 2 > 6 > 7. Quinolones affected the most sensitive strain(s) at concentrations of 12-75 μg L(-1). The MARA bioassay exhibited different spectra of toxic responses to microbial strains for the first and second generation quinolones. However, for first generation quinolones strain 6 was substantially more sensitive than the other microorganisms, while second generation quinolones were most toxic to strain 3, followed by 6 then 4. In this instance, the three strains belong to two different phylogenetic groups-strain 3 is γ-proteotype and strains 4 and 6 are β-proteotype.
authors.affiliation: Department of Environmental Health Sciences, Medical University of Warsaw, Warsaw, Poland. grzegorz.nalecz-jawecki@wum.edu.pl
authors.forename: G
authors.initials: G
authors.lastname: Nałecz-Jawecki
authors.forename: K
authors.initials: K
authors.lastname: Wadhia
authors.forename: B
authors.initials: B
authors.lastname: Adomas
authors.forename: A I
authors.initials: AI
authors.lastname: Piotrowicz-Cieślak
authors.forename: J
authors.initials: J
authors.lastname: Sawicki
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000633:toxicity*; D001419:Bacteria / Q000145:classification / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D001681:Biological Assay / Q000379:methods; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods; D015363:Quinolones / Q000494:pharmacology / Q000633:toxicity; D018570:Risk Assessment / Q000379:methods; D013754:Tetracyclines / Q000494:pharmacology / Q000633:toxicity; D018675:Toxicity Tests / Q000379:methods*; D019155:Veterinary Drugs / Q000494:pharmacology / Q000633:toxicity*; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones; D013754:Tetracyclines; D019155:Veterinary Drugs