AIM: The purpose of this study was to determine how various compounds known to be positive mutagens, contribute to the development of mutations leading to ciprofloxacin resistance in Salmonella enterica subsp. enterica serotype Typhimurium. The molecular mechanism of ciprofloxacin resistance in treated strains was investigated. METHODS: A modified version of the incorporation plate test was used for quantitative determination of ciprofloxacin resistant mutants and for assessment of the mutation frequency induced by the positive mutagens in different concentrations. An AS-PCR-RFLP for monitoring of gyrA mutations was applied. RESULTS: Mutation frequency, expressed as number of antibiotic resistant colonies per 10(8) viable cells, was much higher after exposure of bacterial cells to 3-(5-nitro-2-furyl) acrylic acid and 2-nitrofluorene. All isolated cultures retain decreased susceptibility to antibiotic after multiple passages in antibiotic-free medium. 2-nitrofluorene was the best inducer of mutations in gyrA and in regulation genes affecting suppression of synthesis of outer membrane porins. 3-(5-nitro-2-furyl) acrylic acid gives rise to overproduction of efflux pump. CONCLUSIONS: The data suggest that antibiotic resistance may not be only a consequence of misuse of antibiotics. A polluted environment as well as food processing could contribute to this unwanted process.
- MeSH
- akryláty farmakologie MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence genetika MeSH
- bakteriální proteiny genetika MeSH
- ciprofloxacin farmakologie MeSH
- DNA gyráza genetika MeSH
- fluoreny farmakologie MeSH
- látky znečišťující vzduch farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- mutace účinky léků MeSH
- mutační rychlost MeSH
- mutageny farmakologie MeSH
- nitrofurany farmakologie MeSH
- poriny biosyntéza MeSH
- proteiny vnější bakteriální membrány biosyntéza MeSH
- regulace genové exprese u bakterií MeSH
- Salmonella typhimurium účinky léků genetika MeSH
- Publikační typ
- časopisecké články MeSH
Staphylococcus xylosus, Staphylococcus equorum, and Staphylococcus epidermidis strains were isolated from Bryndza cheese and identified using PCR method. The antimicrobial susceptibility of these strains was assessed using disc diffusion method and broth microdilution method. The highest percentage of resistance was detected for ampicillin and oxacillin, and in contrary, isolates were susceptible or intermediate resistant to ciprofloxacin and chloramphenicol. Fourteen of the S. xylosus isolates (45%) and eleven of the S. equorum isolates (41%) exhibited multidrug resistance. None of the S. epidermidis isolate was multiresistant. The phenotypic resistance to oxacillin was verified by PCR amplification of the gene mecA.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence * MeSH
- mikrobiální testy citlivosti MeSH
- potravinářská mikrobiologie * MeSH
- rezistence na methicilin MeSH
- Staphylococcus klasifikace účinky léků izolace a purifikace MeSH
- sýr mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The effect of H(2)O(2) on the induction of ciprofloxacin (CFL) resistant mutants of Salmonella enterica subsp. enterica serovar Typhimurium was evaluated and determinants of CFL resistance in the mutants were analyzed. Factors associated with CFL resistance in H(2)O(2)-induced mutants included (i) mutations in gyrA gene, predominantly (63 %) Asp(87)-->Asn and less (37 %) Ser(83)-->Phe substitutions, (ii) mutations in the regulatory genes of MarRAB or SoxRS or in the individual structural genes of these operons. Such mutations are induced by H(2)O(2) in a much lower extent. Reduced OmpF expression simultaneously with enhanced efflux was detected only in one mutant strain and 20 % of mutant strains had increased CFL efflux from the cells.
- MeSH
- antibakteriální látky farmakologie metabolismus MeSH
- bakteriální léková rezistence MeSH
- bakteriální proteiny genetika metabolismus MeSH
- ciprofloxacin farmakologie metabolismus MeSH
- DNA gyráza genetika metabolismus MeSH
- missense mutace MeSH
- mutageneze MeSH
- peroxid vodíku farmakologie MeSH
- Salmonella typhimurium genetika metabolismus účinky léků MeSH
