Antibiotics, detection sulfonamides

Table 13.7 provides information on the antibiotic and sulfonamide violations detected during 1992-1994. Sample sizes differed in the various animal slaughter classes in different years. Thus, it would not be appropriate to attribute undue significance to the number of violations detected of an individual compound. Table 13.7 does provide relevant information about the specific compounds that produced violative residue concentrations in food animals during that period. Residue violations for more than one compound might occasionally occur in the same animal. 

Font, H., J. Adrian, R. Galve, et al. 2008. Immunochemical assays for direct sulfonamide antibiotic detection in milk and hair samples using antibody derivatized magnetic nanoparticles. J. Agric. Food Chem. 56 736-743. 

Vermunt AEM, Stadhouders J, Loeffen GJM, Bakker R, Improvements of the tube diffusion method for detection of antibiotics and sulfonamides in raw milk, Neth. Milk Dairy J. 1993 47 31-40. 

There are at least 40 antibiotics and sulfonamides that may occur in milk. They can be detected and identified by both microbial and chemical methods. 

Urine 50 ml Useful for detecting exposure to alkaloids, metals, dectrolytes, antibiotic drugs, sulfonamides, and oxalates... 

For therapeutic drugs, the highest concentrations in the raw sludge corresponded to the analgesics diclofenac (209 ng g ) and ibuprofen (135 ng g-1), and the sulfonamide antibiotic sulfathiazole (143.0 ng g-1). Next in abundance were the diuretic compounds furosemide (79.9 ng g-1) and hydrochlorothiazide (41.3 ng g-1), and the analgesic ketoprofen (42.4 ng g-1). The remaining PhC were found at concentrations below 40 ng g The list of the 24 detected... 

The bioslurry treatment successfully removed several of the PhC to non-detectable levels after 26 days three histamine H2-receptor antagonists (ranitidine, famotidine, cimetidine), two (1-blockers (atenolol, sotalol), one barbiturate (butalbital) and one antidiabetic compound (glibenclamide). The elimination of the sulfonamide antibiotics sulfapyridine (100%), sulfamethazine (91.0%) and... 

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. 

As occurred with the other antibiotics, commercial immunoassay formats, also available as kits for tetracyclines and penicillins such as the Parallux, the LacTek, or the Charm II, have also been placed on the market for the analysis of sulfonamides (see Table 4). Thus, the Parallux detects sulfamethazine and sulfadimethoxine in raw milk with a LOD of 10 pg L1. The Charm II detects almost all sulfonamides in honey and milk with a LOD in the range from 1 to 10 pg L, whereas LacTek is able to detect sulfamethazine. Moreover, the 5101SULlp and 5101SUDAlp tests reach LOD values for sulfamethazine and sulfadiazine of around 0.2 pg L 1 and they have been applied to the analysis of urine, milk, and plasma. These tests have proved to be efficient as a point of care for on-site applications on farms. Moreover, commercially available antibodies can be found from several sources such as Silver Lake Research, US Biological, Cortex Biochem. Inc., Accurate Chemical Scientific, Fitzgerald Industries International Inc., and Biotrend Chemikalien GmbH. 

FSIS laboratories also use chemical techniques and instrumentation to identify select antibiotic residues. The tetracyclines of interest are identified by thin layer chromatography. Sulfonamides are detected and quantified by fluorescence thin lay chromatography and confirmed by gas chromatography/mass spectrometry. Amoxicillin and gentamycin are identified and/or quantified by high pressure liquid chromatography. Similar techniques are used to identify ionophores and other antimicrobials of interest. 

Other sources of PPCP contamination to groundwater can originate from farms, leaking septic tanks, and lagoons. For instance, Campagnolo et al. (2002) detected several types of antibiotics including macrolides, tetracycline, sulfonamides, and (3-lactams in groundwater samples collected from sites that were in proximity of a swine farm. 

In the period 1992-1994, the drugs and groups of drugs screened by the National Residue Program included antibiotics, sulfonamides, ivermectin, halofuginone, levamisole, and morantel tartrate. The microbial assays applied by FSIS for monitoring antibiotics could detect chiortetracyciine, oxytetracycline, tetracy-... 

Results showed a total of 2.8% of the samples (n 2972) to be inhibitor positive by the Delvotest SP test further examination identified 1.7% as -lactam antibiotics, and 1.1 % as sulfonamides and dapsone. The percentage of chloramphenicol suspicious samples determined by the Charm II test was amazingly high however, tests for confirmation were not available and contamination of the samples by residues of the chloramphenicol-based preservative azidiol could not be excluded with certainty. Low concentrations of streptomycins were also detected in 5.7% of the samples (n 1221), but the MRL was not exceeded. Macrolide and tetracycline residues were not found in significant levels. Model trials with commercially applied yoghurt cultures confirmed how important the compliance to MRLs can be to dairy industry compared to antibiotic-free milk, a pH of 5.0 was reached with a delay of 15 min in the case of contamination with cloxacillin 30 min in the case of penicillin, spiramycin, and tylosin and 45 min in the case of oxytetracycline contamination. 

Microbial inhibition tests are extremely sensitive for -lactam antibiotics, primarily penicillin, but mostly are more than 100-fold less sensitive for other commonly used antibacterials such as macrolides, sulfonamides, tetracyclines, or chloramphenicol (4, 5). Therefore, inhibition tests usually classify residues as belonging to the -lactam group. Antibiotics other than -lactams and sulfonamides can be detected by use of the enzyme penicillinase and aminobenzoic acid, respectively (1, 6). 

However, recent investigations on the effect of the tissue matrix on the detection limits attained by this test have indicated that ceftiofur, sulfonamides, streptomycin, and some macrolide antibiotics cannot be detected in intact meat with the plates and the bacterial strains prescribed in the European four-plate test (81, 82). Two plates of this system were not found suitable for screening sulfamethazine or streptomycin at levels far above the MRL the third plate detected tetracyclines and -lactams up to the MRL levels whereas the fourth was sensitive to -lactams and some but not all macrolides. Detection, on the other hand, of the fluoroquinolones enrofloxacin and ciprofloxacin could only be made possible by an additional Escherichia coli plate not included in the four-plate test. 

Most immunochemical methods published for the determination of sulfonamides in edible animal products, serum, and urine concern sulfamethazine analysis (Table 28.3). Early methods for screening sulfamethazine in swine blood (54) necessitated extraction of the antibiotic from the sample and application of long assay protocols that rendered them impractical for routine analysis in hog slaughterhouses. Later methods developed for the detection of sulfamethazine residues in swine serum (55), urine and muscle (8), and in milk (9) addressed the extraction and assay problems of previous methods. 

Adrian, J., S. Pasche, J-M. Diserens, et al. 2009. Waveguide interrogated optical immunosensor (WIOS) for detection of sulfonamide antibiotics in milk. Biosens. Bioelectron, submitted. 

Another current trend that is well underway is the use of more specific analytical instrumentation that allows less extensive sample preparation. The development of mass spectrometric techniques, particularly tandem MS linked to a HPLC or flow injection system, has allowed the specific and sensitive analysis of simple extracts of biological samples (68,70-72). A similar HPLC with UV detection would require significantly more extensive sample preparation effort and, importantly, more method development time. Currently, the bulk of the HPLC-MS efforts have been applied to the analysis of drugs and metabolites in biological samples. Kristiansen et al. (73) have also applied flow-injection tandem mass spectrometry to measure sulfonamide antibiotics in meat and blood using a very simple ethyl acetate extraction step. This important technique will surely find many more applications in the future. 

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