Antibiotic-resistant Escherichia coli are common causative agents of human urinary tract infections. Organotin compounds (OTCs) are man-made chemicals that may affect the renal function of exposed humans and rodents. OTCs are widely recognized as bactericides. However, many environmental and a few clinically relevant bacteria have been found resistant to high concentrations of some OTCs. We examined the susceptibility from 47 E. coli clinical isolates to 12 antibiotics and 5 OTCs. Minimum inhibitory concentrations were determined by the fully automated Sensititre™ ARIS™ 2X system, and E. coli strains were classified as resistant, intermediate resistant, or sensitive, according to the M07-A10 and M100-S26 criteria from the National Committee for Clinical Laboratory Standards. All 47 E. coli strains were susceptible to amikacin but resistant to imipenem and intermediate resistant to ampicillin, cefuroxime, and chloramphenicol. In addition, 26 strains were resistant and 21 intermediate resistant to aztreonam, 24 strains were resistant and 23 intermediate resistant to ceftazidime, 44 strains were intermediate resistant and 3 sensitive to cephalothin, and 43 strains were intermediate resistant and 4 sensitive to ciprofloxacin. Approximately half of the strains were susceptible to cefepime, cefotaxime, and gentamicin. E. coli strains were also found resistant to triphenyltin, tributyltin, dibutyltin, trimethyltin, or dimethyltin at final concentration between 10 μmol/L and 1 mmol/L, during 72-h in vitro culture. However, higher in vitro growth inhibition was induced by these OTCs in the presence of the efflux pump inhibitor carbonyl cyanide-m-chlorophenyl hydrazone, which suggests that efflux pumps contribute to making antibiotic-resistant E. coli also resistant to OTCs.
- MeSH
- antibakteriální látky farmakologie MeSH
- Escherichia coli účinky léků MeSH
- infekce močového ústrojí mikrobiologie MeSH
- infekce vyvolané Escherichia coli mikrobiologie MeSH
- karbonylkyanid-m-chlorfenylhydrazon farmakologie MeSH
- lidé MeSH
- membránové transportní proteiny metabolismus MeSH
- mikrobiální testy citlivosti MeSH
- mnohočetná bakteriální léková rezistence * MeSH
- organocínové sloučeniny farmakologie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
According to the common view, weak acid uncouplers increase proton conductance of biological (and phospholipid bilayer) membranes, thus effecting H+ fluxes driven by their electrochemical gradients. Under certain conditions, however, uncouplers can induce unexpected effects opposite to the dissipation of H+ gradients. Results are presented here demonstrating CCCP-induced proton influx into Saccharomyces cerevisiae cytosol driven by the electrochemical potentials of CCCP and its CCCP- anions, independent of electrochemical H+-gradient. Another view of week acid uncouplers' action is proposed that is logically consistent with these observations.
- MeSH
- biologický transport účinky léků MeSH
- karbonylkyanid-m-chlorfenylhydrazon farmakologie MeSH
- koncentrace vodíkových iontů účinky léků MeSH
- membránové potenciály * účinky léků MeSH
- protony * MeSH
- rozpřahující látky farmakologie MeSH
- Saccharomyces cerevisiae metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Yeast cells exhibit a negative surface potential due to negative charges at the cell membrane surface. Consequently, local concentrations of cations at the periplasmic membrane surface may be significantly increased compared to their bulk environment. However, in cell suspensions only bulk concentrations of cations can be measured directly. Here we present a novel method enabling the assessment of local pH at the periplasmic membrane surface which can be directly related to the underlying cell surface potential. In this proof of concept study using Saccharomyces cerevisiae cells with episomally expressed pH reporter, pHluorin, intracellular acidification induced by the addition of the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) was measured using synchronously scanned fluorescence spectroscopy (SSF). The analysis of titration curves revealed that the pH at the periplasmic surface of S. cerevisiae cells was about two units lower than the pH of bulk medium. This pH difference was significantly decreased by increasing the ionic strength of the bulk medium. The cell surface potential was estimated to amount to -130 mV. Comparable results were obtained also with another protonophore, pentachlorophenol (PCP).
- MeSH
- fluorescenční spektrometrie metody MeSH
- karbonylkyanid-m-chlorfenylhydrazon MeSH
- koncentrace vodíkových iontů * MeSH
- membránové potenciály * MeSH
- metody MeSH
- periplazma chemie MeSH
- Saccharomyces cerevisiae chemie cytologie MeSH
- zelené fluorescenční proteiny MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- floretin farmakologie MeSH
- hodnoty glomerulární filtrace MeSH
- karbonylkyanid-m-chlorfenylhydrazon farmakologie MeSH
- krysa rodu rattus MeSH
- ledviny fyziologie účinky léků MeSH
- močovina moč MeSH
- oxidativní fosforylace účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
