Doses Of Chlortetracycline Research Articles

The study of the influence of tetracycline and sulfadiazine on biomethane production from manure and apple pomace

Anaerobic digestion is the most popular technic for obtaining biomethane from substrates like cow manure and other organic materials, however, chlortetracycline (CTC) and sulfadiazine (SDZ) which are commonly used in animal husbandry and present in cow manure can adversely affect biomethane yields. In this paper, the results of the influence of an increasing dose of CTC between 10 and 1000 mg×kg−1 and dose of SDZ between 10 and 500 mg×kg−1 on biomethane yield and kinetics for co-fermentation of cow manure and apple pomace experiment was presented. The obtained data during 21 days of lasting batch tests performed under mesophilic conditions allowed the determination of kinetics parameters of biomethane production according to the modified Gompertz model. The biomethane yield for the experiment with CTC differs from 233 to 353 mlCH4, while for the experiment with SDZ from 396 to 455 mlCH4. The kinetics parameters varied in a broad range. The ymax, λ, and Rm were 232–531 ml, 18–66 ml d−1, and –2.9-(–1.7) d for CTC, and 533–653 ml, 20–21 ml d−1, and –4.5-(–0.8) d for SDZ, respectively. With the high antibiotics dose, the biomethane yield decreased due to the inhibitive effect on microorganisms. The experiment showed that antibiotics had an inhibitory effect on biomethane production, at high doses. The biomethane yield had been reduced by 32.3 % at 1000 mg×kg−1 of CTC and by 13.9 % at 500 mg×kg−1 of SDZ. Interestingly, small doses (<100 mg×kg-1) did not affect significantly methane yield and sometimes increased it. Obtained results showed that the co-fermentation of apple pomace and manure performance may be affected by high doses of antibiotics. Depending on the dose and the antibiotic type it affects the biomethane yield, production rate, or lag phase differently.

Tetracycline resistance genes persist in soil amended with cattle feces independently from chlortetracycline selection pressure

Antibiotic residues and antibiotic resistance genes originating from animal waste represent environmental pollutants with possible human health consequences. In this study, we addressed the question whether chlortetracycline (CTC) residues in soils can act as selective pressure enhancing the persistence of tetracycline (TC-r) resistance genes in grassland soils receiving cattle feces. We performed a soil microcosm experiment, using 3 grassland soils with different management history, which were incubated with feces from conventionally raised dairy cows. The microcosms included treatments with a low dose (0.2 mg kg−1), a high dose (100 mg kg−1) and no CTC. The presence and abundance of TC-r genes tet(O), tet(Q) and tet(W) and the intI1 gene coding for class 1 integrase were assessed with real-time PCR after 0, 14, 28, 56 and 86 d of incubation. The genes tet(Q) and intI1 persisted in all feces-containing treatments for at least 28 d, and tet(W) and tet(O) for at least 86 d, though they went close to limits of quantification after 14–28 d in most cases. The soil, but not the dose of CTC, significantly affected the gene persistence. Concluding, certain TC-r genes originating from cattle feces may persist in soil for several months independently from antibiotic selection pressure.

Physiological and molecular responses of the earthworm (Eisenia fetida) to soil chlortetracycline contamination

This study aims to evaluate toxic effects of exposure to chlortetracycline (CTC) in soil on reproductive endpoints (juvenile counts and cocoon counts), biochemical responses, and genotoxic potentials of the earthworm Eisenia fetida. Results showed that juvenile counts and cocoon counts of the tested earthworms were reduced after exposure to CTC. The effective concentrations (EC50 values) for juvenile and cocoon counts were 96.1 and 120.3 mg/kg, respectively. Treatment of earthworms with CTC significantly changed the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione S-transferase (GST). An increase in malondialdehyde (MDA) indicated that CTC could cause cellular lipid peroxidation in the tested earthworms. The percentage of DNA in the tail of single-cell gel electrophoresis of coelomocytes as an indication of DNA damage increased after treatment with different doses of CTC, and a dose-dependent DNA damage of coelomocytes was found. In conclusion, CTC induces physiological responses and genotoxicity on earthworms.

Evaluating the Effects of Chlortetracycline on the Proliferation of Antibiotic-Resistant Bacteria in a Simulated River Water Ecosystem

Antibiotics and antibiotic metabolites have been found in the environment, but the biological activities of these compounds are uncertain, especially given the low levels that are typically detected in the environment. The objective of this study was to estimate the selection potential of chlortetracycline (CTC) on the antibiotic resistance of aerobic bacterial populations in a simulated river water ecosystem. Six replicates of a 10-day experiment using river water in continuous flow chemostat systems were conducted. Each replicate used three chemostats, one serving as a control to which no antibiotic was added and the other two receiving low and high doses of CTC (8 microg/liter and 800 microg/liter, respectively). The addition of CTC to the chemostats did not impact the overall level of cultivable aerobic bacteria (P = 0.51). The high-CTC chemostat had significantly higher tetracycline-resistant bacterial colony counts than both the low-CTC and the control chemostats (P < 0.035). The differences in resistance between the low-CTC and control chemostats were highly nonsignificant (P = 0.779). In general a greater diversity of tet resistance genes was detected in the high-CTC chemostat and with a greater frequency than in the low-CTC and control chemostats. Low levels of CTC in this in vitro experiment did not select for increased levels of tetracycline resistance among cultivable aerobic bacteria. This finding should not be equated with the absence of environmental risk, however. Low concentrations of antibiotics in the environment may select for resistant bacterial populations once they are concentrated in sediments or other locations.

Origin of chlortetracycline in pig tissue.

Violative chlortetracycline (CTC) residues in excess of the maximum residue limit (MRL) have been identified in 0.9% of all pigs tested at slaughter in Northern Ireland. Three experiments were carried out to investigate the possible reasons. In Experiment 1, pigs were fed CTC at therapeutic levels (300 mg kg-1 head-1 d-1) for 7 days and were slaughtered at day 0, 2, 4, 6, 8 and 10 following CTC withdrawal. Muscle, liver and kidney cortex and medulla samples were analysed for CTC residues by using high-performance liquid chromatography (HPLC). In all tissues, residues were less than the MRL from day 2 onwards. Mean CTC concentrations in kidney cortex were greater than medulla concentrations (p < 0.05). In Experiment 2, feed spiked with a sub-therapeutic dose of CTC (40 mg kg-1) was fed to six pigs that were slaughtered after 4, 8 and 12 days of medication. Violative CTC residues were not detected. In Experiment 3, short term supra-therapeutic administration was examined. Eight pigs received 500 mg kg-1 CTC head-1 d-1 for 1 or 2 days and were killed in pairs, 24 and 48 h following the final medicated feed. Violative levels were detected in both groups after 24 h only. It is concluded that: firstly, recommended CTC withdrawal periods are sufficient to avoid violative carcass residues; secondly, violative residues do not arise from sub-therapeutic dosing but can arise from supra-therapeutic dosing which could occur with inadequately mixed feed; and thirdly, the difference in kidney cortex and medullary CTC concentrations is significant from a regulatory perspective.

The role of the low resistance period in determining the effective dosage of chlortetracycline in mice. Immunological investigations in experimental chemotherapy. IV.

In various experimental infections inthe mouse, the single doses of chlortetracycline were determined which, when given simultaneously with the infection, prevent death of the animals. Serum concentrations of the antibiotic were measured in mice treated with 80–100% effective doses. During the initial period of infection, which is characterized by insufficient defence (low resistance period), these concentrations are invariably above or approximately equal to the minimum bacteriostatic concentration established in vitro. Hence, it is concluded that in animal experiments the dosage is dependent not only on the in vitro sensitivity of the infectious agent but also on the length of the LRP, during which the micro-organisms have to be controlled by a bacteriostatic agent.

The role of microbial flora in the hepatotoxicity of chlortetracycline in vivo: A study with germfree mice

Studies with germfree mice have revealed that chlortetracycline (CTC) hepatotoxicity does not depend on secondary effects related to modification of the indigenous microflora but that it is the consequence of a direct drug action. Germfree (GF) and conventionalized (CONV) mice, injected intraperitoneally with large doses of CTC, both developed signs of hepatotoxicity: liver weight, total lipids, and lipid fractions (glycerides, cholesterol, phospholipids) increased, while liver water and protein decreased; activity of the liver enzymes (glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, glutamic dehydrogenase, urea cleavage enzyme, and arginase) all decreased, even below that of liver protein concentration. In general, the effect of CTC on the GF mouse was more severe than on the CONV: lipids rose higher, while protein fell lower. In each type of mouse, the concentration of liver glycerides increased most. Fasting exacerbated all these effects especially in the CONV mouse. There were no significant differences between the livers of GF and CONV untreated mice in any of the parameters measured, except for total lipids and glycerides, which were lower in the GF liver. Thus, the presence of an indigenous flora appears not only to attenuate the lipogenic response of the liver to CTC but also to influence the liver lipi composition of the untreated mouse. Our results are consistent with the hypothesis that CTC interferes with protein metabolism of the liver in at least two broad ways: by exerting a catabolic or antianabolic affect, in that liver protein, in general, is decreased after CTC; and by interfering with metalloenzyme action by chelation with metal cofactors, leaving those enzymes relatively unaffected which require no metal cofactors.

食品防腐剤に関する研究-IV

Acquisition of resistance against chlortetracycline (CTC) by Pseudomonas fluorescens, which is closely associated with putrefaction of fish and shellfish, was studied. The results may be summarized as follows: 1. Three starins of P8. fluorescens were exposed to CTC of either a constant dose at the maximal tolerance level (M. T. L.) of each strain or 0.1 ppm, or an increasing dose at M. T. L. at each stage. After 60 successive subculturings in nutrient broth (Difco) containing a constant dose of CTC, the organisms acquired 4 to 16-fold higher resistance at the M. T. L. and 2 to 8-fold at 0.1 ppm, while the corresponding values obtained at the increasing dose were 16 to 64-fold that of the original culture (Figs. 1 and 2). The resistance acquired in vitro seemed to be comparatively stable since 25 successive subculturings of the in vitro resistant organisms in plain nutrient broth held almost the same level of their resistance. 2. A complete cross-resistance against CTC and oxytetracycline was observed. A slight cross-resistance against chloramphenycol was recorded with the CTC-resistant organisms, while that against streptomycine was not appreciable (Table 1). 3. No marked difference in the biochemical characters, especially those relating to putrefaction, was observed between the resistant and sensitive strains (Fig. 3). 4. The distribution curve of resistance of individual cells of a sensitive strain obtained by plotting the numbers of the colonies counted in agar plates added with various levels of CTC appears to be a S shape (Fig. 4), which indicates heterologous sensitivity to CTC by individual cells. While, the curves for the resistant descendants are composed of two linear lines crossing at nearly right angle, which means the majority of the individuals has the same level of resistance. Neither the sensitive nor resistant strain showed CTC-dependence because the largest number of colonies was counted in the plates without CTC.

Vitamin B complex for skin and mucous membrane reactions to chloramphenicol; intramuscular injections in prevention and treatment.

THE USE of wide spectrum antibiotics by mouth, namely, chlortetracycline (Aureomycin), chloramphenicol, and oxytetracycline (Terramycin), has produced reactions in the mucous membranes and adjacent skin, often more disturbing than the disease for which these drugs may be prescribed. One of us (S. O.) noted that among patients being treated for syphilis with large oral doses of chlortetracycline, chloramphenicol, and oxytetracycline there occurred a significant number of mucous membrane reactions ranging from simple glossitis to involvement of the whole lining of the mouth and anogenital regions. The syphilis patients being treated at Gallinger Municipal Hospital (now District of Columbia General Hospital) Rapid Treatment Center, Washington, D. C., were drawn from a low-income, presumably malnourished group. The signs and symptoms in the mucous membranes and adjacent skin which developed frequently while these patients were receiving chlortetracycline and chloramphenicol so closely resembled the vitamin B deficiency picture that it was assumed