Environmental tetracyclines

Macrolide antibiotics (clarithromycin, dehydroerythromycin, etc.) and sulfonamides (sulfamethoxazole, sulfadimethoxine, sulfamethazine, and sulfathi-azole) are the most prevalent antibiotics found in the environment with levels around a few micrograms per liter, whereas fluoroquinolones, tetracyclines, and penicillins have been detected in fewer cases and usually at low concentrations (nanograms per liter) [3,20,23,72]. This result is not surprising, since penicillins are easily hydrolyzed and tetracyclines readily precipitate with cations such as calcium and are accumulated in sewage sludge or sediments. Several reviews have reported the environmental occurrence of different antibiotics in aquatic and soil compartments. Some of these data are detailed in Table 1. 

We have found only one attempt to use immunoassays to detect sulfonamides in environmental samples. As in the case of penicillins and tetracyclines and also for fluoroquinolones (see below), Campagnolo et al. [84] measured sulfonamides in water samples proximal to a farm in Iowa using a commercial Charm II RIA test, accomplishing a LOD of 5 pg L 1 for sulfamethazine. 

Cbee-Sanford J.C., R.I. Aminov, I.J. Krapac, N. Garrigues-Jeanjean, and R.I. Mackie (2001). Occurrence and diversity of tetracycline resistance genes in lagoons and groundwater under-l)dng two swine production facilities. Applied and Environmental Microbiology 67 1494-1502. 

Halling-Sprensen B., G. Sengelpv, and J. Tjpmelund (2002). Toxicity of tetracyclines and tetracycline degradation products to environmentally relevant bacteria, including selected tetracycline-resistant bacteria. Archives of Environmental Contamination and Toxicology 42 263-271. 

Rhodes G., G. Huys, J. Swings, P. Mcgarm, M. Hiney, P. Smith, and R.W. Pickup (2000). Distribution of oxytetracycline resistance plasmids between aeromonads in hospital and aquaculture environments Implication of Tni 721 in dissemination of the tetracycline resistance determinant Tet A. Applied and Environmental Microbiology 66 3883-3890. 

Sassman S.A. and L.S. Lee (2005). Sorption of three tetracyclines by several soils Assessing the role of pH and cation exchange. Environmental Science and Technology 39 7452-7459. 

The application of MIPs as the stationary phase in solid-phase extraction (SPE), often referred to as molecularly imprinted polymer solid-phase extraction (MIS P E), is a rapidly growing area [197-199]. With MISPE, highly specific enrichment of substances present at trace levels is possible. The technique has been applied to the analysis of drugs, for example, caffeine [200], scopolamine [201], naproxen [202], tetracycline [203], cholesterol [204] and local anesthetics [205], as well as environmental pollutants, exemplified by organophosphate flame retardants [206-208], triazines in soil and vegetable samples [71] and naphthalene sulfonates in river water [209]. 

Relatively few reports in the literature describe environmental concentrations, fate, and transport of monensin. Compared with tetracyclines and macrolides, monensin is not tightly adsorbed to soil and has been detected in river water and aquatic sediments in Colorado " and in streams in southern Ontario. 

A relatively small number of environmental studies in the literature relate to tetracyclines. The sorption behavior of these drugs is characterized by persistence and low mobility and accounts for their superficial location in soil profiles and their paucity in runoff water. The enviromental fate of oxytetracycline used in aquaculture was extensively researched (cited by Boxall ). In these studies, oxytetracycline has been detected in wild fauna and in the sediment around flsh farms. Soil samples collected from regions with intensive livestock production in Germany " and the UK have been shown to contain tetracyclines, which possibly originate from manure. 

The stability of various classes at different pH values makes it less than ideal to extract some antibiotics under the same conditions. Tetracyclines are more stable at pH 3-4 than at pH > 5, and changes in pH can lead to the formation of their epimers and even further degradation. Macrolides and f)-lactams are stable at neutral or slightly basic conditions (i.e., pH > 8 or 8.5). Erythromycin degrades to erythromycin-H2O with loss of one H2O molecule at low pH " and is often measured as erythromycin-H20 at m/z 716 in environmental samples but not in food. The... 

Gueimonde, M., Florez, A., van Hoek, A., Stuer-Lauridsen, B., Strpman, R, Reyes-Gavilan, C., et al. (2010). Genetic basis of tetracycline resistance in Bifidobacterium animalis subsp. lactis. Applied and Environmental Microbiology, 76, 3364-3369. 

The principal analytical methods employed in the analysis of pharmaceuticals in aqueous environmental samples include both GC and FC coupled to MS or MS/MS. In general, FC-MS methods have demonstrated lower relative standard deviations than GC-MS methods that have derivatization prior to analysis. FC-ESI-MS/MS is presented as the technique of choice for polar, unstable, and high molecular mass compounds, such as most pharmaceuticals and their metabolites. MS detection has preferably been performed with the ESI interface. An analytical protocol applying FC-ESI-MS/MS with previous filtration of the water sample, with addition of NaiEDTA to avoid complexation of analytes (especially tetracyclines) with metals present in the water, was proposed for the analysis of antibiotics corresponding to the classes of macrolides, sulfonamides, penicillins, and tetracyclines in water samples. 

Although CDs are generally used in the mobile phase as additives to improve separation, their application as extracting agent and sensitivity enhancer of the detection was also reported. Thus, a saturated solution of (3-CD was employed for the extraction of five polycyclic aromatic hydrocarbons (PAHs) from environmental samples. The application of (3-CD enhanced the efficacy of extraction and increased the sensitivity of fluorescence detection. The capacity of (3-CD to enhance the sensitivity of the chemi-luminscence detection of tetracyclines (oxytetracycline, tetracycline, and metacycline) has also been established. 

Andersen, S.R. and Sandaa, R.A. (1994) Distribution of tetracycline resistance determinants among gram-negative bacteria isolated from polluted and unpolluted marine sediments. Applied and Environmental Microbiology 60,908-912. 

However, now the trend is switching to investigations in which the more direct impact of antibiotics on soil microbiology and productivity are being studied, including some recent reports from China, which is ranked first in the world in terms of annual production of at least two of the most commonly used tetracycline derivatives [116 ], and where these compounds are widely used. For example, Chinese shrimps and prawns have been banned in Europe and the USA, because of their high content of antibiotics, such as tetracyclines [117 ], reflecting extensive use of antibiotics that may have environmental consequences in China. 

The literature data present some examples of sensors for the detection of several antibiotics and antihypertensive and anti-inflammatory drugs currently used in urban areas. The detection of antibiotic residues in environmental samples through the use of various disposable electrochemical sensors has proved the capacity of these sensors for fast, low-cost, and sensitive detection. Tetracyclines, as an important class of antibiotics, were investigated on gold SPEs using cyclic voltammetry... 

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