Due to the extensive use of antimicrobial agents in human and veterinary medicine, residues of various antimicrobials get into wastewater and, subsequently, surface water. On the one hand, a combination of processes in wastewater treatment plants aims to eliminate chemical and biological pollutants; on the other hand, this environment may create conditions suitable for the horizontal transfer of resistance genes and potential selection of antibiotic-resistant bacteria. Wastewater and surface water samples (Morava River) were analyzed to determine the concentrations of 10 antibiotics and identify those exceeding so-called predicted no-effect environmental concentrations (PNECs). This study revealed that residues of five of the tested antimicrobials, namely ampicillin, clindamycin, tetracycline, tigecycline and vancomycin, in wastewater samples exceeded the PNEC. Vancomycin concentrations were analyzed with respect to the detected strains of vancomycin-resistant enterococci (VRE), in which the presence of resistance genes, virulence factors and potential relationship were analyzed. VRE were detected in 16 wastewater samples (11%) and two surface water samples (6%). The PNEC of vancomycin was exceed in 16% of the samples. Since the detected VRE did not correlate with the vancomycin concentrations, no direct relationship was confirmed between the residues of this antimicrobials and the presence of the resistant strains.
- Publikační typ
- časopisecké články MeSH
Antibiotic resistance presents an ever increasing threat to human health. Dissemination of resistance is related to the widespread use of antibiotics in human as well as veterinary medicine. Selection of resistant bacterial strains may occur upon contact with low concentrations of antibiotics including subinhibitory levels. Sewage system, waste water treatment plants and receiving watercourses comprise an environment where large bacterial populations are exposed to anthropogenic antibiotic residues. According to some hypotheses, selection taking place in such environment is a significant source of resistant pathogens. This review article provides pertinent information on antibiotic resistance and origin of antibiotic residues in the environment and summarizes relevant original articles reporting determination of antibiotic residues along with resistant phenotypes or genetic markers of resistance in municipal waste waters and anthropogenically impacted aquatic environment. The original literature is discussed in terms of judging the significance of the selection process in these environments.
Cíl: V současné době byly identifikovány tři defekty v purinové de novo syntéze (PDNS). V případě deficitních enzymů jsou v tělních tekutinách pacientů akumulovány abnormální defosforylované substráty (aminoimidazolové ribosidy). Cílem této práce bylo studovat hmotově-spektrometrické vlastnosti aminoimidazolových ribosidů spojených s druhou polovinou PDNS. Metody: Aminoimidazolové ribosidy byly syntetizovány a chemicky charakterizovány. Technika kapalinová chromatografie s hmotnostní spektrometrií byla aplikována pro strukturní identifikaci. MS analýza byla provedena na LCQ hmotnostním spektrometru s iontovou pastí (Finnigan MAT, San Jose, USA). Pro ionizaci byla zvolena chemická ionizace za atmosferického tlaku. Výsledky: Účinnost syntézy ribosidů byla více než 90% a obdržená fragmentační spektra potvrdila jejich identitu. Při fragmentaci ztrácí imidazolový kruh substituenty ve formě malých molekul (NH3, CO2 nebo CO). Sukcinylaminoimidazol karboxamid ribosidu (SAICAr) odštěpuje buď N-sukcinokarboxamid jako celek, nebo se z něj pouze odštěpují skupiny vody z karboxylových skupin. Otevření imidazolového kruhu nebylo sledováno u žádné látky. Závěr: Výše popsaná charakteristika může být užitečná pro vývoj nových metod pro diagnostiku známých či zatím neodhalených defektů druhé poloviny PDNS.
Objectives: Three defects have been identified in purine de novo synthesis (PDNS). Dephosphorylated substrates (imidazole ribosides) of the deficient enzymes are accumulated in body fluids in affected patients. The aim of this work was to investigate mass spectrometric properties of aminoimidazole ribosides related to the second half of PDNS. Methods: These aminoimidazole ribosides were synthesised and chemically characterised. Liquid chromatography- -mass spectrometry technique was applied for structural identification. MS analysis was carried out using an LCQ ion trap mass spectrometer (Finnigan MAT, San Jose, USA). Atmospheric pressure chemical ionization source was employed. Results: Synthesis yielded ribosides with more than 90% purity and obtained fragmentation spectra confirmed their identity. The imidazole ring loses its substituents in the form of small molecules (NH3, CO2 or CO) in mass spectrometry fragmentation. The N-succinocarboxamide group of succinylaminoimidazole carboxamide riboside (SAICAr) either loses water from the free carboxyl groups or breaks away as a whole. Opening of the imidazole ring was not observed for any compound. Conclusions: Characteristics described above can be useful for development of new methods for diagnosing of known as well as unrevealed defects of second part of PDNS.
- MeSH
- aminoimidazolkarboxamid diagnostické užití chemie MeSH
- finanční podpora výzkumu jako téma MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí metody MeSH
- poruchy metabolismu purinů a pyrimidinů diagnóza enzymologie MeSH
- ribonukleosidy diagnostické užití chemická syntéza chemie MeSH
