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Sample records for chloramphenicol

  1. Chloramphenicol Injection

    MedlinePlus

    ... treat certain types of serious infections caused by bacteria when other antibiotics cannot be used. Chloramphenicol injection ... antibiotics. It works by stopping the growth of bacteria..Antibiotics such as chloramphenicol injection will not work ...

  2. Chloramphenicol bioassay.

    PubMed

    Bannatyne, R M; Cheung, R

    1979-07-01

    An accurate plate diffusion bioassay for chloramphenicol is described, in which the fast-replicating Beneckea natriegens and 1.5% salt agar are used. Zones of inhibition were well defined after 3 h, and the limit of sensitivity of the method was around 2 mug/ml. The concurrent presence of gentamicin did not influence the assay. The assay is simple to carry out and duplicate assays can be performed with as little as 100 mug of capillary blood.

  3. Chloramphenicol: new perspectives on an old drug.

    PubMed

    Powell, D A; Nahata, M C

    1982-04-01

    Chloramphenicol is an old antibiotic being used with increasing frequency in serious childhood infections largely due to the emergence of ampicillin-resistant Hemophilus influenzae type b. Because of this renewed popularity and the recent availability of accurate analytical techniques for measurement of chloramphenicol, there have been many recent articles examining the pharmacokinetics of chloramphenicol and its two major prodrug esters, chloramphenicol succinate and chloramphenicol palmitate. New data from these studies include the incomplete bioavailability of chloramphenicol succinate, the possible superior bioavailability of chloramphenicol palmitate vs. chloramphenicol succinate, and the wide interpatient variability in chloramphenicol clearance. These observations, coupled with the known serious hematologic toxicity (reversible bone marrow suppression or irreversible aplastic anemia) and metabolic toxicity (gray baby syndrome) associated with chloramphenicol use, require that initial antibiotic doses be selected by age and be carefully individualized by measurement of peak serum chloramphenicol concentrations.

  4. Chloramphenicol: properties and clinical use.

    PubMed

    Laferriere, C I; Marks, M I

    1982-01-01

    Chloramphenicol was introduced into medical practice in 1949. At therapeutic concentrations of 10 to 20 micrograms drug per ml, the drug inhibits bacterial ribosomal and, to a lesser extent, mammalian mitochondrial protein synthesis but concentrations above 60 micrograms drug per ml induce progressive reduction of oxygen-dependent cellular metabolism. Some adverse reactions (e.g. bone marrow suppression and the "gray baby syndrome") reflect these effects. The pathogenesis of chloramphenicol-induced aplastic anemia remains unclear. Chloramphenicol is most bioavailable after oral administration and has a remarkable ability to diffuse into body fluids and tissues. However, there are wide interindividual variations in its metabolism and elimination, particularly in newborns. Chloramphenicol is indicated for invasive ampicillin-resistant H. influenzae infections; for patients allergic to penicillin with pneumococcal, meningococcal or H. influenzae meningitis; in patients under 8 years of age with Rocky Mountain spotted fever; and for the treatment of brain abscess and other severe anaerobic infections (excluding endocarditis) due to B. fragilis. Other indications include selected patients with Salmonella meningitis or carditis, rickettsioses and intraocular infections. Unravelling the pathogenesis of chloramphenicol-induced aplastic anemia is critical to more widespread application of this remarkable antimicrobial.

  5. Pharmacokinetics of chloramphenicol following administration of intravenous and subcutaneous chloramphenicol sodium succinate, and subcutaneous chloramphenicol, to koalas (Phascolarctos cinereus).

    PubMed

    Black, L A; McLachlan, A J; Griffith, J E; Higgins, D P; Gillett, A; Krockenberger, M B; Govendir, M

    2013-10-01

    Clinically normal koalas (n = 19) received a single dose of intravenous (i.v.) chloramphenicol sodium succinate (SS) (25 mg/kg; n = 6), subcutaneous (s.c.) chloramphenicol SS (60 mg/kg; n = 7) or s.c. chloramphenicol base (60 mg/kg; n = 6). Serial plasma samples were collected over 24-48 h, and chloramphenicol concentrations were determined using a validated high-performance liquid chromatography assay. The median (range) apparent clearance (CL/F) and elimination half-life (t(1/2)) of chloramphenicol after i.v. chloramphenicol SS administration were 0.52 (0.35-0.99) L/h/kg and 1.13 (0.76-1.40) h, respectively. Although the area under the concentration-time curve was comparable for the two s.c. formulations, the absorption rate-limited disposition of chloramphenicol base resulted in a lower median C(max) (2.52; range 0.75-6.80 μg/mL) and longer median tmax (8.00; range 4.00-12.00 h) than chloramphenicol SS (C(max) 20.37, range 13.88-25.15 μg/mL; t(max) 1.25, range 1.00-2.00 h). When these results were compared with susceptibility data for human Chlamydia isolates, the expected efficacy of the current chloramphenicol dosing regimen used in koalas to treat chlamydiosis remains uncertain and at odds with clinical observations. © 2012 John Wiley & Sons Ltd.

  6. 21 CFR 520.390a - Chloramphenicol tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... Because of potential antagonism, chloramphenicol should not be administered simultaneously with penicillin.... Because of potential antagonism, chloramphenicol should not be administered simultaneously with...

  7. 21 CFR 520.390a - Chloramphenicol tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... Because of potential antagonism, chloramphenicol should not be administered simultaneously with penicillin.... Because of potential antagonism, chloramphenicol should not be administered simultaneously with...

  8. Killing of Serratia marcescens biofilms with chloramphenicol.

    PubMed

    Ray, Christopher; Shenoy, Anukul T; Orihuela, Carlos J; González-Juarbe, Norberto

    2017-03-29

    Serratia marcescens is a Gram-negative bacterium with proven resistance to multiple antibiotics and causative of catheter-associated infections. Bacterial colonization of catheters mainly involves the formation of biofilm. The objectives of this study were to explore the susceptibility of S. marcescens biofilms to high doses of common antibiotics and non-antimicrobial agents. Biofilms formed by a clinical isolate of S. marcescens were treated with ceftriaxone, kanamycin, gentamicin, and chloramphenicol at doses corresponding to 10, 100 and 1000 times their planktonic minimum inhibitory concentration. In addition, biofilms were also treated with chemical compounds such as polysorbate-80 and ursolic acid. S. marcescens demonstrated susceptibility to ceftriaxone, kanamycin, gentamicin, and chloramphenicol in its planktonic form, however, only chloramphenicol reduced both biofilm biomass and biofilm viability. Polysorbate-80 and ursolic acid had minimal to no effect on either planktonic and biofilm grown S. marcescens. Our results suggest that supratherapeutic doses of chloramphenicol can be used effectively against established S. marcescens biofilms.

  9. Interaction of Chloramphenicol Tripeptide Analogs with Ribosomes.

    PubMed

    Tereshchenkov, A G; Shishkina, A V; Tashlitsky, V N; Korshunova, G A; Bogdanov, A A; Sumbatyan, N V

    2016-04-01

    Chloramphenicol amine peptide derivatives containing tripeptide fragments of regulatory "stop peptides" - MRL, IRA, IWP - were synthesized. The ability of the compounds to form ribosomal complexes was studied by displacement of the fluorescent erythromycin analog from its complex with E. coli ribosomes. It was found that peptide chloramphenicol analogs are able to bind to bacterial ribosomes. The dissociation constants were 4.3-10 µM, which is 100-fold lower than the corresponding values for chloramphenicol amine-ribosome complex. Interaction of the chloramphenicol peptide analogs with ribosomes was simulated by molecular docking, and the most probable contacts of "stop peptide" motifs with the elements of nascent peptide exit tunnel were identified.

  10. Persistence of chloramphenicol residues in calf tissues.

    PubMed

    Korsrud, G O; Naylor, J M; MacNeil, J D; Yates, W D

    1987-07-01

    Twenty-one 5 to 18 day old calves were administered 11 mg chloramphenicol in propylene glycol per kg body weight intramuscularly twice daily for three days. Groups of calves were euthanized with a barbiturate overdose at 5, 21, 42 and 70 days after the last dose was administered. Serum, kidney, analyzed for the drug using a quantitative gas chromatographic method with a detection limit of five parts per billion. After five days of withdrawal, chloramphenicol was detected in all the injection sites and in 6 out of 16 of the other samples. After 21 days of withdrawal, chloramphenicol was detected in all the injection sites and in one each of the serum, liver and muscle samples. After 42 days of withdrawal, chloramphenicol was detected in the injection sites only, and after 70 days of withdrawal it was not detected in any of the samples.

  11. 21 CFR 522.390 - Chloramphenicol injection.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Chloramphenicol injection. 522.390 Section 522.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS §...

  12. 21 CFR 522.390 - Chloramphenicol injection.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Chloramphenicol injection. 522.390 Section 522.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS §...

  13. 21 CFR 522.390 - Chloramphenicol injection.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloramphenicol injection. 522.390 Section 522.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS §...

  14. 21 CFR 522.390 - Chloramphenicol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Chloramphenicol. 522.390 Section 522.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS §...

  15. 21 CFR 522.390 - Chloramphenicol injection.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Chloramphenicol injection. 522.390 Section 522.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS §...

  16. Effect of Ribosomal Wash Factors on Inhibition by Chloramphenicol

    PubMed Central

    Cameron, Helen J.; Rogers, Samuel J.; Julian, Gordon R.

    1972-01-01

    In vitro protein-synthesizing systems from Escherichia coli can be categorized as either chloramphenicol-sensitive or chloramphenicol-insensitive. The chloramphenicol-sensitive systems used in this study required the presence of factors removed from ribosomes with 1.0 m NH4Cl when chromatographically purified ribosomes were used for amino acid incorporation. These ribosomal wash factors inhibited but did not eliminate amino acid incorporation in chloramphenicol-insensitive systems. For both systems, addition of increasing amounts of the ribosomal wash factors increased the sensitivity to chloramphenicol inhibition. PMID:4597705

  17. Characterization of two metagenome-derived esterases that reactivate chloramphenicol by counteracting chloramphenicol acetyltransferase.

    PubMed

    Tao, Weixin; Lee, Myung Hwan; Yoon, Mi-Young; Kim, Jin-Cheol; Malhotra, Shweta; Wu, Jing; Hwang, Eul Chul; Lee, Seon-Woo

    2011-12-01

    Function-driven metagenomic analysis is a powerful approach to screening for novel biocatalysts. In this study, we investigated lipolytic enzymes selected from an alluvial soil metagenomic library, and identified two novel esterases, EstDL26 and EstDL136. EstDL26 and EstDL136 reactivated chloramphenicol from its acetyl derivates by counteracting the chloramphenicol acetyltransferase (CAT) activity in Escherichia coli. These two enzymes showed only 27% identity in amino acid sequence to each other; however both preferentially hydrolyzed short-chain p-nitrophenyl esters (< or =C5) and showed mesophilic properties. In vitro, EstDL136 catalyzed the deacetylation of 1- and 3- acetyl and 1,3-diacetyl derivates; in contrast, EstDL26 was not capable of the deacetylation at C1, indicating a potential regioselectivity. EstDL26 and EstDL136 were similar to microbial hormone-sensitive lipase (HSL), and since chloramphenicol acetate esterase (CAE) activity was detected from two other soil esterases in the HSL family, this suggests a distribution of CAE among the soil microorganisms. The isolation and characterization of EstDL26 and EstDL136 in this study may be helpful in understanding the diversity of CAE enzymes and their potential role in releasing active chloramphenicol in the producing bacteria.

  18. 21 CFR 520.390c - Chloramphenicol palmitate oral suspension.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... Treatment of bacterial pulmonary infections, infections of the urinary tract, enteritis, and infections associated with canine distemper that are caused by organisms susceptible to chloramphenicol. (3)...

  19. 21 CFR 520.390c - Chloramphenicol palmitate oral suspension.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... Treatment of bacterial pulmonary infections, infections of the urinary tract, enteritis, and infections associated with canine distemper that are caused by organisms susceptible to chloramphenicol. (3)...

  20. 21 CFR 520.390c - Chloramphenicol palmitate oral suspension.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... Treatment of bacterial pulmonary infections, infections of the urinary tract, enteritis, and infections associated with canine distemper that are caused by organisms susceptible to chloramphenicol. (3)...

  1. 21 CFR 524.390a - Chloramphenicol ophthalmic ointment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... bacterial conjunctivitis caused by pathogens susceptible to chloramphenicol. (3) Limitations. Continue... conjunctivitis, attempts should be made to determine through susceptibility testing, which antibiotics will be...

  2. 21 CFR 524.390a - Chloramphenicol ophthalmic ointment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... bacterial conjunctivitis caused by pathogens susceptible to chloramphenicol. (3) Limitations. Continue... conjunctivitis, attempts should be made to determine through susceptibility testing, which antibiotics will be...

  3. Chloramphenicol and expression of multidrug efflux pump in Enterobacter aerogenes.

    PubMed

    Ghisalberti, Didier; Masi, Muriel; Pagès, Jean-Marie; Chevalier, Jacqueline

    2005-03-25

    Chloramphenicol has been reported to act as an inducer of the multidrug resistance in Escherichia coli. A resistant variant able to grow on plates containing 64 microg/ml chloramphenicol was obtained from the Enterobacter aerogenes ATCC 13048-type strain. Chloramphenicol resistance was due to an active efflux of this antibiotic and it was associated with resistance to fluoroquinolones and tetracycline, but not to aminoglycoside or beta-lactam antibiotics. MDR in the chloramphenicol-resistant variant is linked to the overexpression of the major AcrAB-TolC efflux system. This overexpression seems unrelated to the global Mar and the local AcrR regulatory pathways.

  4. 21 CFR 524.390 - Chloramphenicol ophthalmic ointment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Chloramphenicol ophthalmic ointment. 524.390 Section 524.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... § 524.390 Chloramphenicol ophthalmic ointment. (a) Specifications. Each gram contains 10 milligrams...

  5. Structural basis for chloramphenicol tolerance in Streptomyces venezuelae by chloramphenicol phosphotransferase activity.

    PubMed

    Izard, T

    2001-08-01

    Streptomyces venezuelae synthesizes chloramphenicol (Cm), an inhibitor of ribosomal peptidyl transferase activity, thereby inhibiting bacterial growth. The producer escapes autoinhibition by its own secondary metabolite through phosphorylation of Cm by chloramphenicol phosphotransferase (CPT). In addition to active site binding, CPT binds its product 3-phosphoryl-Cm, in an alternate product binding site. To address the mechanisms of Cm tolerance of the producer, the crystal structures of CPT were determined in complex with either the nonchlorinated Cm (2-N-Ac-Cm) at 3.1 A resolution or the antibiotic's immediate precursor, the p-amino analog p-NH(2)-Cm, at 2.9 A resolution. Surprisingly, p-NH(2)-Cm binds CPT in a novel fashion. Additionally, neither 2-N-Ac-Cm nor p-NH(2)-Cm binds to the secondary product binding site.

  6. Type B Chloramphenicol Acetyltransferases Are Responsible for Chloramphenicol Resistance in Riemerella anatipestifer, China

    PubMed Central

    Huang, Li; Yuan, Hui; Liu, Ma-Feng; Zhao, Xin-Xin; Wang, Ming-Shu; Jia, Ren-Yong; Chen, Shun; Sun, Kun-Feng; Yang, Qiao; Wu, Ying; Chen, Xiao-Yue; Cheng, An-Chun; Zhu, De-Kang

    2017-01-01

    Riemerella anatipestifer causes serositis and septicaemia in domestic ducks, geese, and turkeys. Traditionally, the antibiotics were used to treat this disease. Currently, our understanding of R. anatipestifer susceptibility to chloramphenicol and the underlying resistance mechanism is limited. In this study, the cat gene was identified in 69/192 (36%) R. anatipestifer isolated from different regions in China, including R. anatipestifer CH-2 that has been sequenced in previous study. Sequence analysis suggested that there are two copies of cat gene in this strain. Only both two copies of the cat mutant strain showed a significant decrease in resistance to chloramphenicol, exhibiting 4 μg/ml in the minimum inhibitory concentration for this antibiotic, but not for the single cat gene deletion strains. Functional analysis of the cat gene via expression in Escherichia coli BL21 (DE3) cells and in vitro site-directed mutagenesis indicated that His79 is the main catalytic residue of CAT in R. anatipestifer. These results suggested that chloramphenicol resistance of R. anatipestifer CH-2 is mediated by the cat genes. Finally, homology analysis of types A and B CATs indicate that R. anatipestifer comprises type B3 CATs. PMID:28298905

  7. Type B Chloramphenicol Acetyltransferases Are Responsible for Chloramphenicol Resistance in Riemerella anatipestifer, China.

    PubMed

    Huang, Li; Yuan, Hui; Liu, Ma-Feng; Zhao, Xin-Xin; Wang, Ming-Shu; Jia, Ren-Yong; Chen, Shun; Sun, Kun-Feng; Yang, Qiao; Wu, Ying; Chen, Xiao-Yue; Cheng, An-Chun; Zhu, De-Kang

    2017-01-01

    Riemerella anatipestifer causes serositis and septicaemia in domestic ducks, geese, and turkeys. Traditionally, the antibiotics were used to treat this disease. Currently, our understanding of R. anatipestifer susceptibility to chloramphenicol and the underlying resistance mechanism is limited. In this study, the cat gene was identified in 69/192 (36%) R. anatipestifer isolated from different regions in China, including R. anatipestifer CH-2 that has been sequenced in previous study. Sequence analysis suggested that there are two copies of cat gene in this strain. Only both two copies of the cat mutant strain showed a significant decrease in resistance to chloramphenicol, exhibiting 4 μg/ml in the minimum inhibitory concentration for this antibiotic, but not for the single cat gene deletion strains. Functional analysis of the cat gene via expression in Escherichia coli BL21 (DE3) cells and in vitro site-directed mutagenesis indicated that His79 is the main catalytic residue of CAT in R. anatipestifer. These results suggested that chloramphenicol resistance of R. anatipestifer CH-2 is mediated by the cat genes. Finally, homology analysis of types A and B CATs indicate that R. anatipestifer comprises type B3 CATs.

  8. Effects of concurrent drug therapy and of feeding on plasma chloramphenicol levels after oral administration of chloramphenicol in dogs.

    PubMed

    Watson, A D

    1977-01-01

    On separate occasions, five fasted adult greyhounds were dosed orally with 50 mg chloramphenicol/kg, both alone and in conjunction with other drugs. The same five dogs were later given 50 mg chloramphenicol/kg when fed ad lib. Chloramphenicol levels in plasma were determined at intervals after dosing. The intial plasma chloramphenicol levels were higher when the drug was administered concurrently with calcium lactate tablets (50 mg/kg) or a proprietary enteric mixture containing kaolin, pectin, aluminium hydroxide and belladonna extract. Lower plasma levels resulted when the antibiotic was given with dry extract of belladonna (20 mg/dog) or intravenous chlorpromazine (2 mg/kg). There was no significant effect with coated ferrous gluconate tablets (30 mg/kg). Feeding ad lib increased the initial chloramphenicol levels, but produced lower levels subsequently.

  9. Inhibition of existing denitrification enzyme activity by chloramphenicol

    USGS Publications Warehouse

    Brooks, M.H.; Smith, R.L.; Macalady, D.L.

    1992-01-01

    Chloramphenicol completely inhibited the activity of existing denitrification enzymes in acetylene-block incubations with (i) sediments from a nitrate-contaminated aquifer and (ii) a continuous culture of denitrifying groundwater bacteria. Control flasks with no antibiotic produced significant amounts of nitrous oxide in the same time period. Amendment with chloramphenicol after nitrous oxide production had begun resulted in a significant decrease in the rate of nitrous oxide production. Chloramphenicol also decreased (>50%) the activity of existing denitrification enzymes in pure cultures of Pseudomonas denitrificans that were harvested during log- phase growth and maintained for 2 weeks in a starvation medium lacking electron donor. Short-term time courses of nitrate consumption and nitrous oxide production in the presence of acetylene with P. denitrificans undergoing carbon starvation were performed under optimal conditions designed to mimic denitrification enzyme activity assays used with soils. Time courses were linear for both chloramphenicol and control flasks, and rate estimates for the two treatments were significantly different at the 95% confidence level. Complete or partial inhibition of existing enzyme activity is not consistent with the current understanding of the mode of action of chloramphenicol or current practice, in which the compound is frequently employed to inhibit de novo protein synthesis during the course of microbial activity assays. The results of this study demonstrate that chloramphenicol amendment can inhibit the activity of existing denitrification enzymes and suggest that caution is needed in the design and interpretation of denitrification activity assays in which chloramphenicol is used to prevent new protein synthesis.

  10. Electron Microscopy of Chloramphenicol-treated Escherichia coli

    PubMed Central

    Morgan, Councilman; Rosenkranz, Herbert S.; Carr, Howard S.; Rose, Harry M.

    1967-01-01

    Thin sections of Escherichia coli were examined by electron microscopy at sequential intervals after addition and then removal of chloramphenicol. The first changes, occurring at 1 hr after exposure to the drug, were disappearance of the ribosomes and aggregation of the nuclear material toward the center of the bacteria. At 2 hr, aggregates of abnormal cytoplasmic granules first appeared and subsequently increased in size. By 23 hr, amorphous, electron-dense material had accumulated within, and at the periphery of, the nuclear matrix. With the removal of chloramphenicol, the bacteria became normal in appearance, passing through a series of stages that were sequential but not synchronous. At 145 min after removal of chloramphenicol, bacteria were encountered in the process of abnormal division. The influence of deoxyribonucleic acid and ribonucleic acid synthesis, and of energy metabolism, upon the changes seen electron microscopically in chloramphenicol-treated cells, was investigated by selectively inhibiting these functions with hydroxyurea, azauracil, and sodium azide, respectively. Images PMID:5337775

  11. REVERSIBLE CHLORAMPHENICOL-INDUCED BONE MARROW DEPRESSION IN THE CHIMPANZEE.

    DTIC Science & Technology

    Chloramphenicol administered by intravenous or oral routes at a dose rate of 150 mg/kg/day to a total of 13 chimpanzees caused mild depression of...erythroid depression was not sufficient to cause a significant decrease in circulating red cell mass. Increased numbers of vacuolated proerythroblasts...hemorrhagic anemia as well, increase of the numbers of vacuolated precursor cells in the chimpanzee seemed associated with modifying factors rather than chloramphenicol administration alone. (Author)

  12. Emulsion of Chloramphenicol: an Overwhelming Approach for Ocular Delivery.

    PubMed

    Ashara, Kalpesh C; Shah, Ketan V

    2017-03-01

    Ophthalmic formulations of chloramphenicol have poor bioavailability of chloramphenicol in the ocular cavity. The present study aimed at exploring the impact of different oil mixtures in the form of emulsion on the permeability of chloramphenicol after ocular application. Selection of oil mixture and ratio of the components was made by an equilibrium solubility method. An emulsifier was chosen according to its emulsification properties. A constrained simplex centroid design was used for the assessment of the emulsion development. Emulsions were evaluated for physicochemical properties; zone of inhibition, in-vitro diffusion and ex-vivo local accumulation of chloramphenicol. Validation of the design using check-point batch and reduced polynomial equations were also developed. Optimization of the emulsion was developed by software Design® expert 6.0.8. Assessment of the osmolarity, ocular irritation, sterility testing and isotonicity of optimized batch were also made. Parker Neem®, olive and peppermint oils were selected as an oil phase in the ratio 63.64:20.2:16.16. PEG-400 was selected as an emulsifier according to a pseudo-ternary phase diagram. Constrained simplex-centroid design was applied in the range of 25-39% water, 55-69% PEG-400, 5-19% optimized oil mixture, and 1% chloramphenicol. Unpaired Student's t-test showed for in-vitro and ex-vivo studies that there was a significant difference between the optimized batch of emulsion and Chloramphenicol eye caps (a commercial product) according to both were equally safe. The optimized batch of an emulsion of chloramphenicol was found to be as safe as and more effective than Chloramphenicol eye caps.

  13. New insights into chloramphenicol biosynthesis in Streptomyces venezuelae ATCC 10712.

    PubMed

    Fernández-Martínez, Lorena T; Borsetto, Chiara; Gomez-Escribano, Juan Pablo; Bibb, Maureen J; Al-Bassam, Mahmoud M; Chandra, Govind; Bibb, Mervyn J

    2014-12-01

    Comparative genome analysis revealed seven uncharacterized genes, sven0909 to sven0915, adjacent to the previously identified chloramphenicol biosynthetic gene cluster (sven0916-sven0928) of Streptomyces venezuelae strain ATCC 10712 that was absent in a closely related Streptomyces strain that does not produce chloramphenicol. Transcriptional analysis suggested that three of these genes might be involved in chloramphenicol production, a prediction confirmed by the construction of deletion mutants. These three genes encode a cluster-associated transcriptional activator (Sven0913), a phosphopantetheinyl transferase (Sven0914), and a Na(+)/H(+) antiporter (Sven0915). Bioinformatic analysis also revealed the presence of a previously undetected gene, sven0925, embedded within the chloramphenicol biosynthetic gene cluster that appears to encode an acyl carrier protein, bringing the number of new genes likely to be involved in chloramphenicol production to four. Microarray experiments and synteny comparisons also suggest that sven0929 is part of the biosynthetic gene cluster. This has allowed us to propose an updated and revised version of the chloramphenicol biosynthetic pathway.

  14. Kinetic studies of peptide bond formation. Effect of chloramphenicol.

    PubMed

    Fernandez-Muñoz, R; Vazquez, D

    1973-08-01

    There might be an undetermined order in the interaction of the substrates with the ribosomes in the reaction of CACCA-Leu-Ac with puromycin to form Ac-Leu-puromycin and CACCA ('fragment reaction'). Km 0°=6×10(-4) M for the puromycin · ribosome interaction. Chloramphenicol totally blocks the 'fragment reaction' as a consequence of a single interaction with the ribosome of Kd 0°=2.2×10(-6) M. The inhibition by chloramphenicol of the 'fragment reaction' is mixed competitive for puromycin.

  15. Effect of bio-electrochemical system on the fate and proliferation of chloramphenicol resistance genes during the treatment of chloramphenicol wastewater.

    PubMed

    Guo, Ning; Wang, Yunkun; Yan, Lei; Wang, Xinhua; Wang, Mingyu; Xu, Hai; Wang, Shuguang

    2017-03-30

    Bioelectrochemical systems can effectively degrade antibiotics, but there is the need to better understand the fate of antibiotic resistance bacteria and antibiotic resistance genes during the bioelectrochemical degradation of antibiotics. In this study, a BES was developed as a platform to investigate the fate of chloramphenicol resistance bacteria (CRB) and the expression of chloramphenicol resistance genes (CRGs) under different operating conditions during chloramphenicol biodegradation. The results indicated that chloramphenicol was effectively removed and chloramphenicol removal efficiency could be improved under less chloramphenicol concentration and more negative cathode potential. Higher chloramphenicol concentration enhanced the enrichment of CRB and expression of CRGs. Furthermore, the abundances of CRB were enhanced under more negative cathode potential, the expression of CRGs under less negative cathode potential were induced. However, both the enrichment of CRB and expression of CRGs could be moderated under a medium cathode potential. This result could provide the scientific reference for research about the fate of antibiotic resistance genes in bioelectrochemical systems.

  16. 21 CFR 520.390c - Chloramphenicol palmitate oral suspension.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloramphenicol palmitate oral suspension. 520.390c Section 520.390c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS §...

  17. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS §...

  18. 21 CFR 520.390c - Chloramphenicol palmitate oral suspension.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Chloramphenicol palmitate oral suspension. 520.390c Section 520.390c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN.... Not for use in animals that are raised for food production. Must not be used in meat-, egg-, or...

  19. 21 CFR 524.390b - Chloramphenicol ophthalmic solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... first 2 days. (2) Indications for use. Treatment of bacterial conjunctivitis caused by organisms susceptible to chloramphenicol. Therapy should be continued for 48 hours after the eye appears normal. (3) Limitations. Therapy for cats should not exceed 7 days. As with other antibiotics, prolonged use may result...

  20. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.390...

  1. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.390...

  2. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.390...

  3. 21 CFR 520.390 - Chloramphenicol oral dosage forms.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Chloramphenicol oral dosage forms. 520.390 Section 520.390 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.390...

  4. Oxidative phosphorylation in fractionated bacterial systems: effect of chloramphenicol.

    PubMed

    Cavari, B Z; Kalra, V K; Brodie, A F

    1971-12-01

    Chloramphenicol was found to have a direct effect on the respiratory chain of Mycobacterium phlei cells grown in the presence of this drug. Analysis of the respiratory chain components revealed that the presence of chloramphenicol during growth resulted in a partial inhibition in the synthesis of the cytochromes. However, a stimulation in oxidative phosphorylation was observed with the cell-free extract of cells grown in the presence of chloramphenicol. The oxidation of succinate was found to be stimulated 20 to 130%, depending on the particular extract, whereas the oxidation of reduced nicotinamide adenine dinucleotide (NADH) was found to be similar to that of extracts obtained from cells grown in the absence of the drug. Of particular interest was the finding that the cell-free extract of cells grown in the presence of the drug exhibited an increased level of phosphorylation (17 to 100%) when NADH was used as the electron donor. Chloramphenicol appears to affect a component of the respiratory chain between the flavoprotein and cytochrome c. Fractionation of the electron transport particles revealed an increased level of cytochrome b in the fractions which exhibited a stimulation in oxidative phosphorylation.

  5. Acquisition of a determinant for chloramphenicol resistance by coliphage lambda.

    PubMed Central

    Gottesman, M M; Rosner, J L

    1975-01-01

    A determinanat for chloramphenicol resistance, cam, initially detected on a resistance transfer factor (RTF) and since transferred to phage P1, may be acquired from P1 by coliphage lambda. Lambdapcam are obtained when a lambda prophage is induced in bacteria which also harbor P1 cam prophage. Lambdacam formation is not dependent upon host Rec or lambda Red recombination functions. Electron microscopic heteroduplex analysis shows that the cam locus in two lambdapcams is a 5% addition of DNA in the b2 region of lambda, not contiguous with att. The extent and nucloetide sequence of the DNA insertion in the two independent lambdapcam isolates appear to be the same though they are located at different sites within the b2 region. We conclude that the determinant for chloramphenicol resistance is contained on a unique piece of DNA which facilitates its insertion into a number of unrelated genomes. Images PMID:1061090

  6. In vitro antibacterial activity of fluorinated analogs of chloramphenicol and thiamphenicol.

    PubMed Central

    Syriopoulou, V P; Harding, A L; Goldmann, D A; Smith, A L

    1981-01-01

    We evaluated the in vitro antimicrobial activity of Sch 24893, Sch 25298, and Sch 25393, three novel analogs of chloramphenicol and thiamphenicol. All of the analogs had minimal inhibitory concentrations of less than or equal to 10 micrograms/ml for 18 chloramphenicol-thiamphenicol-resistant strains of Shigella dysenteriae and 21 strains of resistant Salmonella typhi. The analogs were also more active than were chloramphenicol and thiamphenicol against chloramphenicol-resistant enteric bacteria, including six strains of Escherichia coli, seven strains of Klebsiella pneumoniae, and two strains of Enterobacter cloacae. Fifty-three strains of ampicillin-resistant Haemophilus influenzae were uniformly susceptible to chloramphenicol, thiamphenicol, and the three analogs. Sch 25298 was the most active compound tested (minimal inhibitory concentration, 0.5 microgram/ml for all strains). Four of seven chloramphenicol-thiamphenicol-resistant Haemophilus strains were susceptible to the fluorinated analogs. Of the three Haemophilus strains which were resistant to chloramphenicol, thiamphenicol, and the analogs, two contained less than 10% of the chloramphenicol acetyltransferase activity of the strains which were resistant to only chloramphenicol and thiamphenicol. We conclude that fluorinated analogs of chloramphenicol and thiamphenicol have considerable in vitro activity against a broad spectrum of chloramphenicol-thiamphenicol-resistant, gram-negative bacteria. PMID:6957162

  7. Tetracycline and chloramphenicol efficiency against selected biofilm forming bacteria.

    PubMed

    Liaqat, Iram; Sumbal, Fareeha; Sabri, Anjum Nasim

    2009-08-01

    Despite the constantly increasing need for new antimicrobial agents, antibiotic drug discovery and development seem to have greatly decelerated in recent years. Presented with the significant problem of advancing antimicrobial resistance, the global scientific community has attempted to find alternative solutions; one of the most promising ones is the evaluation and use of old antibiotic compounds. A number of old antibiotic compounds, such as aminoglycosides, chloramphenicol, and tetracycline, are re-emerging as valuable alternatives for the treatment of difficult-to-treat infections. This study examined the in vitro potency for biofilm formation of five isolates (Klebsiella sp., Pseudomonas aeruginosa, Achromobacter sp., Klebsiella pneumoniae, and Bacillus pumilis) and the effects of antibiotics on these biofilms. Furthermore the quantitative analysis of planktonic, loosely attached cells, and their susceptibility to antibiotics was also determined. Twitching motility was observed to determine any effect in the biofilm forming capability of the isolates. All the isolates tested were efficient biofilm-forming strains in the polypropylene and borosilicate test tubes. Standard bacterial enumeration technique and CV staining produced equivalent results both in biofilm and planktonic assays. The biofilm formation of all the strains was affected in the presence of tetracycline or chloramphenicol. Highly significant decrease (P < 0.01) in biofilm formation was observed by treatment with chloramphenicol compared to tetracycline. In addition, the two antibiotics also affected adversely the planktonic and loosely attached cells of all isolates. Thus, testing the effects of older antibiotics on biofilms may supply useful information in addition to standard in vitro testing, particularly in diseases where biofilm formation is involved in the pathogenesis.

  8. In Vitro Activity of Cinoxacin, Ampicillin, and Chloramphenicol Against Shigella and Nontyphoid Salmonella

    PubMed Central

    Rubinstein, Ethan; Shainberg, Bracha

    1977-01-01

    The in vitro antibacterial activity of cinoxacin was compared with that of ampicillin and chloramphenicol against 26 strains of nontyphoid Salmonella and 44 strains of Shigella. Cinoxacin was found to have a lower minimal inhibitory concentration than ampicillin and chloramphenicol against all Salmonella and Shigella sonnei strains. Cinoxacin had minimal inhibitory concentrations similar to those of chloramphenicol but lower than those of ampicillin against Shigella flexneri and S. boydii strains. PMID:856008

  9. Photocatalytic degradation and drug activity reduction of Chloramphenicol.

    PubMed

    Chatzitakis, A; Berberidou, C; Paspaltsis, I; Kyriakou, G; Sklaviadis, T; Poulios, I

    2008-01-01

    The photocatalytic degradation of Chloramphenicol, an antibiotic drug, has been investigated in aqueous heterogeneous solutions containing n-type oxide semiconductors as photocatalysts. The disappearance of the organic molecule follows approximately a pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. It was observed that, with TiO(2) P-25 as photocatalyst, quantitative degradation of the organic molecule occurs after 4h of illumination. During this time, the dechlorination of the substrate is complete, while the organic nitrogen was recovered in the form of nitrate and ammonium ions. The effect of temperature on the degradation rate of Chloramphenicol shows similar apparent activation energies for both TiO(2) P-25 and ZnO photocatalysts. The initial apparent photonic efficiency (zeta(0)) of the photo-oxidation and the mineralization under various experimental conditions have been calculated, while the Kirby-Bauer disc diffusion method showed a 100% reduction of the drug activity after 90 min of photocatalytic treatment.

  10. Liposomal gel with chloramphenicol: characterisation and in vitro release.

    PubMed

    Pavelić, Zeljka; Skalko-Basnet, Natasa; Jalsenjak, Ivan

    2004-12-01

    The aim of our study was to develop a liposomal carrier system for the local treatment of bacterial vaginosis, capable to efficiently deliver entrapped drug during an extended period of time. Chloramphenicol was entrapped in liposomes composed of egg phosphatidylcholine/egg phosphatidylgycerol-sodium (9:1, molar ratio) and prepared by two different methods, the proliposome method and the polyol dilution method. Both liposome preparations were characterised and compared for particle size, polydispersity, entrapment efficiency and tested for in vitro stability in media that simulate human vaginal conditions (buffer pH 4.5 and vaginal fluid simulant). To achieve application viscosity of liposomes and to further improve their stability, liposomes prepared by the proliposome method were incorporated in the bioadhesive gel made of Carbopol 974P NF resin. In vitro release studies of liposomes incorporated in the gel have shown a prolonged release of entrapped chloramphenicol compared to control gel. Even after 24 hours of incubation in the vaginal fluid simulant, more than 40% of the originally entrapped drug was still retained in the gel. Storage stability studies have proven the ability of the Carbopol 974P NF gel to preserve the original size distribution of incorporated liposomes. All the performed experiments confirm the applicability of liposomes as a novel drug carrier system for the local treatment of bacterial vaginosis.

  11. Chloramphenicol Is a Substrate for a Novel Nitroreductase Pathway in Haemophilus influenzae▿

    PubMed Central

    Smith, Arnold L.; Erwin, Alice L.; Kline, Toni; Unrath, William C. T.; Nelson, Kevin; Weber, Allan; Howald, William N.

    2007-01-01

    The p-nitroaromatic antibiotic chloramphenicol has been used extensively to treat life-threatening infections due to Haemophilus influenzae and Neisseria meningitidis; its mechanism of action is the inhibition of protein synthesis. We found that during incubation with H. influenzae cells and lysates, chloramphenicol is converted to a 4-aminophenyl allylic alcohol that lacks antibacterial activity. The allylic alcohol moiety undergoes facile re-addition of water to restore the 1,3-diol, as well as further dehydration driven by the aromatic amine to form the iminoquinone. Several Neisseria species and most chloramphenicol-susceptible Haemophilus species, but not Escherichia coli or other gram-negative or gram-positive bacteria we examined, were also found to metabolize chloramphenicol. The products of chloramphenicol metabolism by species other than H. influenzae have not yet been characterized. The strains reducing the antibiotic were chloramphenicol susceptible, indicating that the pathway does not appear to mediate chloramphenicol resistance. The role of this novel nitroreductase pathway in the physiology of H. influenzae and Neisseria species is unknown. Further understanding of the H. influenzae chloramphenicol reduction pathway will contribute to our knowledge of the diversity of prokaryotic nitroreductase mechanisms. PMID:17526758

  12. [Real-time UV imaging of chloramphenicol intrinsic dissolution characteristics from ophthalmic in situ gel].

    PubMed

    Chen, Jian-Xiu; Guo, Zhen; Li, Hai-Yan; Wu, Li; He, Zhong-Gui; Hu, Rong-Feng; Zhang, Ji-Wen

    2013-07-01

    In this paper, chloramphenicol was selected as a model drug to prepare in situ gels. The intrinsic dissolution rate of chloramphenicol from in situ gel was evaluated using the surface dissolution imaging system. The results indicated that intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel decreased significantly when the poloxamer concentration increased. The addition of the thickener reduced the intrinsic dissolution rate of chloramphenicol thermosensitive gel, wherein carbomer had the most impact. Different dilution ratios of simulated tear fluid greatly affected gel temperature, and had little influence on the intrinsic dissolution rate of chloramphenicol from the thermosensitive in situ gel. The pH of simulated tear fluid had little influence on the intrinsic dissolution rate of chloramphenicol thermosensitive in situ gel. For the pH sensitive in situ gel, the dissolution rates of chloramphenicol in weak acidic and neutral simulated tear fluids were slower than that in weak alkaline simulated tear fluid. In conclusion, the intrinsic dissolution of chloramphenicol from in situ gel was dependent on formulation and physiological factors. With advantages of small volume sample required and rapid detection, the UV imaging method can be an efficient tool for the evaluation of drug release characteristics of ophthalmic in situ gel.

  13. 21 CFR 524.390 - Chloramphenicol ophthalmic and topical dosage forms.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloramphenicol ophthalmic and topical dosage... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.390 Chloramphenicol ophthalmic and topical dosage forms....

  14. Rapid pretreatment-free immunochromatographic assay of chloramphenicol in milk.

    PubMed

    Byzova, N A; Zvereva, E A; Zherdev, A V; Eremin, S A; Dzantiev, B B

    2010-05-15

    A pretreatment-free immunochromatographic assay for detection of chloramphenicol (CAP) in milk was developed. The assay is based on competition between CAP molecules in the sample and immobilized CAP-protein conjugate for binding to monoclonal anti-CAP antibodies conjugated with colloidal gold particles (average diameter 30nm). The assay is carried out in the course of sample flowing along test strip with immobilized reactants, and its results can be detected by the naked eye or by a photometric device. Effect of the concentration of immunoreactants on assay characteristics was studied. The assay protocol with maximal sensitivity and reliability was optimized using measured values of brightness of lines. Detection limit for CAP is 10ngmL(-1). Assay duration is 10min, and it can be carried out at room temperature without any additional devices and reactants. The developed test strip has been applied to CAP detection in dairy products.

  15. Phosphorylation of chloramphenicol by a recombinant protein Yhr2 from Streptomyces avermitilis MA4680.

    PubMed

    Rajesh, Thangamani; Sung, Changmin; Kim, Hyeonjeong; Song, Eunjung; Park, Hyung-Yeon; Jeon, Jong-Min; Yoo, Dongwon; Kim, Hyun Joong; Kim, Yong Hyun; Choi, Kwon-Young; Song, Kyung-Guen; Yang, Yung-Hun

    2013-06-15

    Although phosphorylation of chloramphenicol has been shown to occur in the chloramphenicol producer, Streptomyces venezuelae, there are no reports on the existence of chloramphenicol phosphorylase in other Streptomyces species. In the present study, we report the modification of chloramphenicol by a recombinant protein, designated as Yhr2 (encoded by SAV_877), from Streptomyces avermitilis MA4680. Recombinant Yhr2 was expressed in Escherichia coli BL21 (DE3) and the cells expressing this recombinant protein were shown to phosphorylate chloramphenicol to a 3'-O-phosphoryl ester derivative, resulting in an inactivated form of the antibiotic. Expression of yhr2 conferred chloramphenicol resistance to E. coli cells up to 25 μg/mL and in an in vitro reaction, adenosine triphosphate (ATP), guanosine triphosphate (GTP), adenosine diphosphate (ADP) and guanosine diphosphate (GDP) were shown to be the phosphate donors for phosphorylation of chloramphenicol. This study highlights that antibiotic resistance conferring genes could be easily expressed and functionalized in other organisms that do not produce the respective antibiotic.

  16. Lactic Acidosis with Chloramphenicol Treatment in a Child with Cystic Fibrosis.

    PubMed

    Goyer, Isabelle; Iseppon, Massimiliano; Thibault, Céline; Abaji, Rachid; Krajinovic, Maja; Autmizguine, Julie

    2017-01-30

    Children with cystic fibrosis are commonly colonized with multi-resistant bacteria. In such patients, infectious exacerbation may require salvage therapy with uncommonly used antimicrobials, including chloramphenicol. Chloramphenicol is rarely used nowadays because of the associated severe adverse events. We describe the case of a 15-year-old female with terminal cystic fibrosis who required intravenous (IV) chloramphenicol treatment for a Burkholderia cepacia (B. cepacia) exacerbation. The child subsequently developed lactic acidosis and secondary respiratory compensation adding to her baseline respiratory distress. Based on the Naranjo scale, the probability of chloramphenicol being the cause of the hyperlactatemia and associated respiratory distress was rated as probable, as the adverse effects resolved upon discontinuation of the drug. Subsequent genotyping for mitochondrial polymorphism (G3010A) confirmed a possible susceptibility to lactic acidosis from mitochondrial RNA-inhibiting agents such as chloramphenicol. Hyperlactatemia is a rare but life threatening adverse effect that has been previously reported with chloramphenicol exposure, but is not generally thought of. Clinicians should be aware of this potentially life threatening, but reversible adverse event. Lactate should be monitored under chloramphenicol and it should be discontinued as soon as this complication is suspected, especially in patients with low respiratory reserve. © 2017 Journal of Population Therapeutics and Clinical Pharmacology. All rights reserved.

  17. Comparative metabolism of chloramphenicol in germfree and conventional rats.

    PubMed Central

    Wal, J M; Corpet, D E; Peleran, J C; Bories, G F

    1983-01-01

    The action of gut microflora on the metabolism of chloramphenicol (CP) was studied in germfree (GF) and conventional (CV) rats after administration of single oral doses of tritiated CP. There were similarities in the metabolic pathways of CP in the GF and CV animals, i.e., rapid absorption, hepatic glucuroconjugation, and biliary excretion of the CP conjugate. CP, CP-oxamic acid, CP-alcohol, and CP-base were present in similar proportions in the urine of both GF and CV rats. Differences observed included the slow elimination of total radioactivity and a reduced proportion of the urinary excretion versus the fecal excretion in the GF Reduction products which were present in much greater quantities in the urine and feces of CV rats are compatible with the generally described hydrolysis of the CP-glucuronide, followed by a nitroreduction of the CP by the gut microflora and the reabsorption of a part of the products formed. In GF rats, CP-glucuronide was the major fecal metabolite, a portion of it having been reabsorbed and excreted in the urine. Although in lesser amounts, reduction products were still present as urinary metabolites in GF rats. Such a reduction in the tissues might produce active intermediate that could be related to CP toxicity. PMID:6625558

  18. Rapid surface enhanced Raman scattering detection method for chloramphenicol residues

    NASA Astrophysics Data System (ADS)

    Ji, Wei; Yao, Weirong

    2015-06-01

    Chloramphenicol (CAP) is a widely used amide alcohol antibiotics, which has been banned from using in food producing animals in many countries. In this study, surface enhanced Raman scattering (SERS) coupled with gold colloidal nanoparticles was used for the rapid analysis of CAP. Density functional theory (DFT) calculations were conducted with Gaussian 03 at the B3LYP level using the 3-21G(d) and 6-31G(d) basis sets to analyze the assignment of vibrations. Affirmatively, the theoretical Raman spectrum of CAP was in complete agreement with the experimental spectrum. They both exhibited three strong peaks characteristic of CAP at 1104 cm-1, 1344 cm-1, 1596 cm-1, which were used for rapid qualitative analysis of CAP residues in food samples. The use of SERS as a method for the measurements of CAP was explored by comparing use of different solvents, gold colloidal nanoparticles concentration and absorption time. The method of the detection limit was determined as 0.1 μg/mL using optimum conditions. The Raman peak at 1344 cm-1 was used as the index for quantitative analysis of CAP in food samples, with a linear correlation of R2 = 0.9802. Quantitative analysis of CAP residues in foods revealed that the SERS technique with gold colloidal nanoparticles was sensitive and of a good stability and linear correlation, and suited for rapid analysis of CAP residue in a variety of food samples.

  19. Recombinant genomes which express chloramphenicol acetyltransferase in mammalian cells

    SciTech Connect

    Gorman, C.M.; Moffat, L.F.; Howard, B.H.

    1982-09-01

    The authors constructed a series of recombinant genomes which directed expression of the enzyme chloramphenicol acetyltransferase (CAT) in mammalian cells. The prototype recombinant in this series, pSV2-cat, consisted of the beta-lactamase gene and origin of replication from pBR322 coupled to a simian virus 40 (SV40) early transcription region into which CAT coding sequences were inserted. Readily measured levels of CAT accumulated within 48 h after the introduction of pSV2-cat DNA into African green monkey kidney CV-1 cells. Because endogenous CAT activity is not present in CV-1 or other mammalian cells, and because rapid, sensitive assays for CAT activity are available, these recombinants provided a uniquely convenient system for monitoring the expression of foreign DNAs in tissue culture cells. To demonstrate the usefulness of this system, we constructed derivatives of pSV2-cat from which part or all of the SV 40 promoter region was removed. Deletion of one copy of the 72-base-pair repeat sequence in the SV40 promoter caused no significant decrease in CAT synthesis in monkey kidney CV-1 cells; however, an additional deletion of 50 base pairs from the second copy of the repeats reduced CAT synthesis to 11% of its level in the wild type. They also constructed a recombinant, pSVO-cat, in which the entire SV40 promoter region was removed and a unique HindIII site was substituted for the insertion of other promoter sequences.

  20. Kinetic studies on enzymatic acetylation of chloramphenicol in Streptococcus faecalis.

    PubMed Central

    Nakagawa, Y; Nitahara, Y; Miyamura, S

    1979-01-01

    The kinetics of chloramphenicol (CP) acetylation by CP acetyltransferase from Streptococcus faecalis was studied. CP was shown to be acetylated enzymatically to its 3-O-acetyl derivative (3-AcCP) in the presence of acetyl coenzyme A, after which 3-AcCP was converted nonenzymatically to its 1-O-acetyl isomer, 1-O-acetyl CP (1-AcCP). At equilibrium, the 1-AcCP and 3-AcCP were present in a 1:4 ratio. Subsequently the diacetylated product, 1,3-O-O-diacetyl CP [1,3-(Ac)2CP], was enzymatically produced from 1-AcCP by the same enzyme. Theoretical calculation of rate constants (k1, k2, k3) for each successive reaction is as follows: (Formula: see text). This calculation gave k1 = 0.4 min-1, k2 = 0.002 min-1, and k3 = 0.016 min-1. Experimental results agreed closely with these calculated values. Images PMID:119483

  1. Effect of Certain Antimetabolites and of Chloramphenicol on Conjugation of E. coli K-12,

    DTIC Science & Technology

    organisms. The authors studied the effect of chloramphenicol, 5-bromouracil (5-BU), and 8-azaguanine (8-AG) on the conjugation of E . coli K-12 on the transfer of genetic markers from the donor to the recipient.

  2. Aqueous Humor Antimicrobial Activity: In Vitro Analysis after Topical 0.5% Chloramphenicol Application.

    PubMed

    Cagini, Carlo; Dragoni, Annalisa; Orsolini, Giampaolo; Fiore, Tito; Beccasio, Alfredo; Spadea, Leopoldo; Moretti, Amedeo; Mencacci, Antonella

    2017-06-01

    To assess aqueous humor antimicrobial activity in vitro after topical 0.5% chloramphenicol application. This investigation included 63 eyes from 65 cataract surgery patients. The study group of 48 eyes received preoperatively four topical applications of 0.5% chloramphenicol. The control group of 15 eyes was given no topical applications. Aqueous humor samples were collected for in vitro antimicrobial analysis using Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Pasteurella multocida organisms by means of disk diffusion test. No inhibition halo was observed around all aqueous humor samples from all chloramphenicol-treated patients, irrespective of the sample quantity added to the paper disks, with no significant difference from aqueous humor from untreated control patients. Aqueous humor displayed no bactericidal effect against any of the microorganisms evaluated after topical 0.5% chloramphenicol application.

  3. 21 CFR 524.390d - Chloramphenicol-prednisolone ophthalmic ointment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... bacterial conjunctivitis and ocular inflammation caused by organisms susceptible to chloramphenicol. (3) Limitations. Therapy for cats should not exceed 7 days, prolonged use in cats may produce blood dyscrasia. As... institute appropriate therapy. All topical ophthalmic preparations containing corticosteroids, with...

  4. Post-chemiluminescence determination of chloramphenicol based on luminol-potassium periodate system.

    PubMed

    Yang, Xiao Feng; Li, Nian Bing; Luo, Hong Qun

    2012-01-01

    A post-chemiluminescence (PCL) phenomenon was observed when chloramphenicol was injected into a mixture of luminol and potassium periodate after the chemiluminescence (CL) reaction of luminol-potassium periodate had finished. The possible reaction mechanism was proposed based on studies of the CL kinetic characteristics, the CL spectra, the fluorescence spectra and the UV-vis absorption spectra of the related substances. Based on the PCL reaction, a rapid and sensitive method for the determination of chloramphenicol was established. The linear response range was 6.0 × 10(-7) -1.0 × 10(-5) mol/L, with a correlation coefficient of 0.9986. The relative standard deviation (RSD) for 5.0 × 10(-6) mol/L chloramphenicol was 2.3% (n = 11). The detection limit was 1.6 × 10(-7) mol/L. The method has been applied to the determination of chloramphenicol in pharmaceutical samples with satisfactory results.

  5. CraA, a Major Facilitator Superfamily Efflux Pump Associated with Chloramphenicol Resistance in Acinetobacter baumannii▿

    PubMed Central

    Roca, I.; Marti, S.; Espinal, P.; Martínez, P.; Gibert, I.; Vila, J.

    2009-01-01

    Acinetobacter baumannii has been increasingly associated with hospital-acquired infections, and the presence of multidrug resistance strains is of great concern to clinicians. A. baumannii is thought to possess a great deal of intrinsic resistance to several antimicrobial agents, including chloramphenicol, although the mechanisms involved in such resistance are not well understood. In this work, we have identified a major facilitator superfamily efflux pump present in most A. baumannii strains, displaying strong substrate specificity toward chloramphenicol. PMID:19581458

  6. Occurrence of chloramphenicol-resistance genes as environmental pollutants from swine feedlots.

    PubMed

    Li, Juan; Shao, Bing; Shen, Jianzhong; Wang, Shaochen; Wu, Yongning

    2013-03-19

    Chloramphenicol-resistance genes could be propagated to the surrounding environment via agricultural application of swine waste. This study investigated the potential risks of chloramphenicol-resistance genes from swine feedlots and their surrounding environment. We applied a culture-independent method to investigate levels of chloramphenicol-resistance genes in the wastewater from swine feedlots and the correspondingly impacted agricultural fields in Beijing. The cmlA, floR, fexA, cfr, and fexB genes were present in all samples, with the highest absolute concentrations of 1.50 × 10(6) copies/g in soil and 6.69 × 10(6) copies/mL in wastewater. The concentration of chloramphenicol residue was determined by ultra performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS), with the highest concentrations of 0.83 ng/g in soil and 11.5 ng/mL in wastewater. Significant correlations were found between chloramphenicol-resistance genes and chloramphenicol residues (r = 0.79, p = 0.0008) as well as between chloramphenicol-resistance genes in swine feedlots and corresponding agricultural soils (r = 0.84, p = 0.02). Consequently, swine feedlot wastewater could become a source of chloramphenicol-resistance genes, which could then lead to the spread of antibiotic resistance and eventually pose a risk to public health. To our knowledge, this is the first study to examine the occurrence of floR, fexA, cfr, and fexB genes in the environment using a culture-independent method.

  7. Biomimetic piezoelectric quartz crystal sensor with chloramphenicol-imprinted polymer sensing layer.

    PubMed

    Ebarvia, Benilda S; Ubando, Isaiah E; Sevilla, Fortunato B

    2015-11-01

    The measurement of banned antibiotic like chloramphenicol is significant for customer protection and safety. The presence of residual antibiotics in foods and food products of animal origin could pose as health hazards and affect food quality for global acceptance. In this study, the potential of a chloramphenicol sensor based on molecularly imprinted polymer (MIP) coupled with a piezoelectric quartz crystal was explored. The MIP was prepared by precipitation polymerization at 60 °C. Methacrylic acid was used as monomer, trimethylolpropane trimethacrylate (TRIM) as crosslinker, and chloramphenicol as the template. Template removal on the resulting polymer was done by extraction using methanol-acetic acid. Characterization of the MIP and NIP were conducted by spectroscopic and microscopic methods. These further supported the imprinting and rebinding process of chloramphenicol to the polymer matrix. The chloramphenicol sensor was devised by spin-coating onto one side of the 10 MHz AT-cut quartz crystal the MIP suspension in polyvinylchloride-tetrahydrofuran (6:2:1 w/w/v) solution. Optimization of sensor response was performed by varying the type of cross-linker, amount of MIP sensing layer, curing time, and pH. The sensor exhibited good sensitivity of about 73 Hz/log (conc., µg mL(-1)) and good repeatability (rsd<10%). A linear relationship (r(2)=0.9901) between frequency shift and chloramphenicol concentration in the range of 1×10(-6) up to 1×10(-1) µg/mL was obtained. The sensor response was highly selective to chloramphenicol than with other compounds of similar chemical structures. Acceptable percent recovery was obtained for real sample analysis using the sensor. The proposed sensor could be a promising low cost and highly sensitive approach for residual chloramphenicol quantification in food products. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. γ-Cyclodextrin capped silver nanoparticles for molecular recognition and enhancement of antibacterial activity of chloramphenicol.

    PubMed

    Gannimani, Ramesh; Ramesh, Muthusamy; Mtambo, Sphamandla; Pillay, Karen; Soliman, Mahmoud E; Govender, Patrick

    2016-04-01

    Computational studies were conducted to identify the favourable formation of the inclusion complex of chloramphenicol with cyclodextrins. The results of molecular docking and molecular dynamics predicted the strongest interaction of chloramphenicol with γ-cyclodextrin. Further, the inclusion complex of chloramphenicol with γ-cyclodextrin was experimentally prepared and a phenomenon of inclusion was verified by using different characterization techniques such as thermogravimetric analysis, differential scanning calorimetry, (1)H nuclear magnetic resonance (NMR) and two dimensional nuclear overhauser effect spectroscopy (NOESY) experiments. From these results it was concluded that γ-cyclodextrins could be an appropriate cyclodextrin polymer which can be used to functionalize chloramphenicol on the surface of silver nanoparticles. In addition, γ-cyclodextrin capped silver nanoparticles were synthesized and characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and zeta potential analysis. Molecular recognition of chloramphenicol by these cyclodextrin capped silver nanoparticles was confirmed by surface enhanced raman spectroscopy (SERS) experiments. Synergistic antibacterial effect of chloramphenicol with γ-cyclodextrin capped silver nanoparticles was evaluated against Pseudomonas aeruginosa (ATCC 27853), Enterococcus faecalis (ATCC 5129), Klebsiella pneumoniae (ATCC 700603) and Staphylococcus aureus (ATCC 43300). The results from the antibacterial experiment were favourable thus allowing us to conclude that the approach of modifying organic drug molecules with cyclodextrin capped inorganic silver nanoparticles could help to enhance the antibacterial activity of them.

  9. Antimicrobial activity and interference of tobramycin and chloramphenicol on bacterial adhesion to intraocular lenses.

    PubMed

    Drago, L; De Vecchi, E; Nicola, L; Gismondo, M R

    2003-01-01

    The antimicrobial activities of tobramycin and chloramphenicol were evaluated by determining minimum inhibitory and bactericidal concentrations against Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, group A, group B and group G streptococci, Klebsiella spp., Stenotrophomonas maltophilia and ciprofloxacin-resistant and -susceptible Pseudomonas aeruginosa, as well as by evaluating interference on adhesion of slime producer strains of S. aureus and P. aeruginosa to intraocular lens from tobramycin and chloramphenicol pharmaceutical products by scanning electron microscopy. Chloramphenicol was more active against Gram-positive bacteria than was tobramycin, which instead showed higher activity against ciprofloxacin-susceptible P. aeruginosa. Treatment of lenses with the antimicrobial products eradicated the bacterial biofilm, which was already notably reduced after 5 min. This activity was more pronounced for chloramphenicol against S. aureus and for tobramycin against P. aeruginosa. Bacterial adhesion was also significantly reduced when lenses colonized by P. aeruginosa were treated with chloramphenicol, even if they were resistant to this drug. In conclusion, the tested drugs showed marked antibacterial activity, particularly by interfering with bacterial biofilms. The data obtained in this study suggest a specific use of chloramphenicol in topical prophylaxis aimed at avoiding bacterial contaminations. However, further specific in vivo studies are needed to confirm these data.

  10. Randomized comparison of aztreonam and chloramphenicol in treatment of typhoid fever.

    PubMed Central

    Gotuzzo, E; Echevarría, J; Carrillo, C; Sánchez, J; Grados, P; Maguiña, C; DuPont, H L

    1994-01-01

    Patients with clinical typhoid fever plus a blood, bone marrow, or bile positive for Salmonella typhi or Salmonella paratyphi were included in an open clinical trial to compare the efficacy of aztreonam (6 g/day [2 g intravenously every 8 h]) given for 10 days with that of chloramphenicol (50 mg/kg of body weight per day [intravenously or orally]) administered for 14 days. A total of 44 patients, 22 in each group, were included in the study, and both groups were comparable in terms of baseline parameters. All patients randomized to receive chloramphenicol completed the 14 days of treatment, while two patients randomized to receive aztreonam developed an intestinal hemorrhage, and a third patient elected to withdraw from the trial. Defervescence occurred more quickly in the subjects receiving chloramphenicol than in those receiving aztreonam (P < 0.05). All patients in the chloramphenicol group were clinically cured during therapy, while four patients (21%) in the group receiving aztreonam were declared clinical treatment failures. None of the 19 patients receiving aztreonam, compared with 7 of 22 (32%) patients receiving chloramphenicol, had a positive blood culture after 24 h of therapy (P < 0.05). Adverse experiences were unusual and mild. In the study, aztreonam was less effective than chloramphenicol with regard to clinical effectiveness and time of defervescence but was more effective in the elimination of the infecting Salmonella organisms from the bloodstream. PMID:8203854

  11. Identification of the Chloramphenicol-Binding Protein in Escherichia coli Ribosomes by Partial Reconstitution*

    PubMed Central

    Nierhaus, Dagmar; Nierhaus, Knud H.

    1973-01-01

    50S-derived cores were prepared by treatment of 50S subunits with 0.4 M Licl (0.4c core) and 0.8 M Licl (0.8c core), respectively. 0.4c cores bind chloramphenicol whereas 0.8c cores do not. The split proteins obtained during the transitions 0.4c → 0.8c were separated by DEAE-cellulose chromatography and Sephadex G-100 gel filtration. Reconstitution experiments with the fractionated proteins demonstrated that protein L16 is involved in chloramphenicol binding. In contrast to chloramphenicol, the CACCA-(N-acetyl-leucyl) fragment is bound by the 0.8c core, i.e., this core contains the intact p-site moiety of the peptidyltransferase center. Puromycin can inhibit chloramphenicol binding completely. In the concentration range tested (up to 20 mM) the trinucleotide CCA inhibits chloramphenicol binding as effectively as puromycin, whereas an aminoacid mixture shows no inhibition. It is concluded that chloramphenicol acts exclusively on the a-site part of the peptidyltransferase center interfering with the binding of the last two or three nucleotides (3′ end) of aminoacyl-tRNA. Images PMID:4365366

  12. Identification of the chloramphenicol-binding protein in Escherichia coli ribosomes by partial reconstitution.

    PubMed

    Nierhaus, D; Nierhaus, K H

    1973-08-01

    50S-derived cores were prepared by treatment of 50S subunits with 0.4 M Licl (0.4c core) and 0.8 M Licl (0.8c core), respectively. 0.4c cores bind chloramphenicol whereas 0.8c cores do not. The split proteins obtained during the transitions 0.4c --> 0.8c were separated by DEAE-cellulose chromatography and Sephadex G-100 gel filtration. Reconstitution experiments with the fractionated proteins demonstrated that protein L16 is involved in chloramphenicol binding. In contrast to chloramphenicol, the CACCA-(N-acetyl-leucyl) fragment is bound by the 0.8c core, i.e., this core contains the intact p-site moiety of the peptidyltransferase center. Puromycin can inhibit chloramphenicol binding completely. In the concentration range tested (up to 20 mM) the trinucleotide CCA inhibits chloramphenicol binding as effectively as puromycin, whereas an aminoacid mixture shows no inhibition. It is concluded that chloramphenicol acts exclusively on the a-site part of the peptidyltransferase center interfering with the binding of the last two or three nucleotides (3' end) of aminoacyl-tRNA.

  13. Biotransformation of antibiotics. I. Acylation of chloramphenicol by spores of Streptomyces griseus isolated from the Egyptian soil .

    PubMed

    El-Kersh, T A; Plourde, J R

    1976-03-01

    Incubation of spores, washed mycelium or whole cultures of a Streptomyces sp. with chloramphenicol (I) resulted in the loss of in vitro bioactivity of the antibiotic. Gas chromatographic estimation of an appropriate extract revealed that more than 95% of the antibiotic was inactivated under the specified conditions. The spores inactivated chloramphenicol in an inorganic buffer solution, or in distilled water, without the addition of carbohydrate or external co-factor. However, addition of certain carbon sources to the spores showed a pronounced effect on the chloramphenicol transformation process and on the relative concentration of the inactivated products. Time-course studies on the spore-catalyzed chloramphenicol transformation activity showed a maximum activity at 12-hour incubation. Addition of glucose or acetate at this point maintained maximum activity. The transformation products were identified as: chloramphenicol-1-acetate (IIa); chloramphenicol-3-acetate (IIb); chloramphenicol-3-propionate (III); CHLORAMPHENICOL-O-ISOBUTYRATE (IV); chloramphenicol-3-butyrate (V); and chloramphenicol-3-isovalerate (VI), by techniques of TLC, CPC, GC, UV, IR, MS and NMR. The microbial characteristics of the isolated strain include the formation of flexuous gray aerial mycelium with smooth to rough spores, irregular in size. It is an H2S and melanin former, non-chromogenic, and was inhibited by a streptomycin-producing strain of Streptomyces griseus (Krainsky 1914) Waksman and Henrici(1948).

  14. Observation of residues in tissues of chickens exposed to low dietary concentrations of chloramphenicol.

    PubMed

    Rejtharová, Martina; Rejthar, Libor; Čačková, Katarína; Bureš, Jiří; Vernerová, Eva; Hera, Alfred

    2017-04-01

    To investigate potential residues in tissues arising from naturally occurring low levels of chloramphenicol in plant material, feeding studies were conducted with chickens. A common chicken feed was prepared containing 0, 10, 50 and 200 μg kg(-1) chloramphenicol and levels were confirmed by LC-MS/MS. Four separate groups of broiler chickens, eight animals in each group, were fed all their 35-day life with this contaminated feed. They were allowed ad libitum access to this feed and fresh water. After slaughtering the chickens, the residues in muscle and liver tissues were determined using GC/MS-NCI method. No residues were detected in tissues of animals from groups fed with feed containing 0, 10 or 50 µg kg(-1). Low chloramphenicol residual concentrations were observed in a few of the muscle samples obtained from the group of chickens fed with feed containing chloramphenicol in added concentration 200 µg kg(-1). No residues were detected in the remaining samples of this group. These results indicate that when residues of chloramphenicol are detected it is in all probability through illegal use.

  15. Possible association between ocular chloramphenicol and aplastic anaemia—the absolute risk is very low

    PubMed Central

    Laporte, Joan-Ramon; Vidal, Xavier; Ballarín, Elena; Ibáñez, Luisa

    1998-01-01

    Aims To determine whether topical ocular chloramphenicol increases the risk of aplastic anaemia and to estimate the magnitude of this risk, if any. Methods Population-based prospective case-control surveillance of aplastic anaemia in a community of 4.2 million inhabitants from 1980 to 1995 (67.2 million person-years) plus case-population estimate of the risk, based on sales figures of ocular chloramphenicol in the study area during the study period. Results One hundred and forty-five patients with aplastic anaemia and 1,226 controls were included in the analysis. Three cases (2.1%) and 5 controls (0.4%) had been exposed to ocular chloramphenicol during the relevant etiological period. The adjusted odds ratio was 3.77 (95% confidence interval, 0.84–16.90). Two cases had also been exposed to other known causes of aplastic anaemia. The incidence of aplastic anaemia among users of ocular chloramphenicol was 0.36 cases per million weeks of treatment. The incidence among non users was 0.04 cases per million weeks. Conclusions An association between ocular chloramphenicol and aplastic anaemia cannot be excluded. However, the risk is less than one per million treatment courses. PMID:9723830

  16. Chloramphenicol – A Potent Armament Against Multi-Drug Resistant (MDR) Gram Negative Bacilli?

    PubMed Central

    2016-01-01

    Introduction Multidrug-resistant gram-negative bacteria cause infections which are hard to treat and cause high morbidity and mortality. Due to limited therapeutic options there is a renewed interest upon older antimicrobials which had fallen into disuse as a result of toxic side effects. One such antibiotic is chloramphenicol which was sidelined due to reports linking its use with the development of aplastic anaemia. Aim A study was conducted to evaluate the susceptibility of chloramphenicol in light of the emerging problem of multi-drug resistant gram negative bacteria (MDR GNB). Materials and Methods A total of 483 MDR GNB of the 650 consecutive Gram Negative Bacteria isolated from various clinical samples of patients admitted at a tertiary care hospital in Jaipur between January-June 2014 were screened for chloramphenicol susceptibility by the disc diffusion method as per CLSI guidelines. Results The MDR GNB isolates were obtained from 217 (45%) urine, 163 (34%) from respiratory samples, 52(11%) from pus, 42 (9%) from blood and 9 (2%) from body fluids. A 68% of the MDR GNB isolates were found to be sensitive to chloramphenicol. Conclusion Clinicians should always check for the local susceptibility of Gram-negative bacteria to chloramphenicol. This antibiotic has a potential to play a role in the therapeutic management of infections due to MDR GNB pathogens. PMID:27042458

  17. Emergence of resistance to chloramphenicol among vancomycin-resistant enterococcal (VRE) bloodstream isolates.

    PubMed

    Lautenbach, Ebbing; Gould, Carolyn V; LaRosa, Lori A; Marr, Ann Marie; Nachamkin, Irving; Bilker, Warren B; Fishman, Neil O

    2004-02-01

    Therapeutic options for vancomycin-resistant enterococcal (VRE) bloodstream infections are extremely limited. Chloramphenicol is effective when VRE isolates are susceptible to this agent. However, longitudinal trends in chloramphenicol-resistant VRE (CR-VRE) are unknown. The possible association between CR-VRE and antibiotic use has not been studied. We analyzed the antimicrobial susceptibility profiles of all VRE blood isolates from 1991-2000 at our institution. We performed a correlational study to examine the relationship between annual hospital-wide use of specific antibiotics and antibiotic classes and CR-VRE prevalence. During the 10-year study period, the prevalence of CR-VRE increased from 0 to 11% ( P< 0.001, trend). CR-VRE prevalence was correlated only with chloramphenicol use (P=0.05 ) and quinolone use (P= 0.01 ). If these trends continue, dependence on newer, more expensive agents will increase. The correlation between both chloramphenicol use and quinolone use and the prevalence of CR-VRE suggests that efforts to preserve the utility of chloramphenicol in VRE infections may depend on optimizing the use of these agents.

  18. A chromosomal chloramphenicol acetyltransferase determinant from a probiotic strain of Bacillus clausii.

    PubMed

    Galopin, Sébastien; Cattoir, Vincent; Leclercq, Roland

    2009-06-01

    The mechanism of resistance to chloramphenicol was studied in four strains of Bacillus clausii included in a probiotic mixture, which is administered to humans for prevention of gastrointestinal side effects due to oral antibiotic therapy. By cloning experiments, a chloramphenicol acetyltransferase (CAT) gene, cat(Bcl), coding for a putative 228-amino acid CAT protein was identified in B. clausii SIN. The deduced amino acid sequence displayed from 31% to 85% identity with 56 CAT proteins from other Gram-positive bacterial strains. The cat(Bcl) gene was also detected by PCR in the three other B. clausii strains resistant to chloramphenicol, whereas it was absent in the three control strains susceptible to chloramphenicol. Pulse-field gel electrophoresis of total DNA digested by I-CeuI followed by hybridization with a cat-specific probe as well as unsuccessful repeated attempts of in vitro transfer of chloramphenicol resistance to various recipient cells indicated that cat(Bcl) was chromosomally located in all four resistant B. clausii strains.

  19. Temperature and other factors affecting chloramphenicol stimulation of the germination of light-sensitive lettuce seeds.

    PubMed

    Frankland, B; Smith, H

    1967-12-01

    D-threo-chloramphenicol at concentrations ranging from 1000 to 3000 μg/ml stimulated the germination of the light-sensitive seeds of the lettuce (Lactuca sativa L.) varieties Attractie and Grand Rapids. This stimulatory effect of chloramphenicol was markedly temperature dependent, increasing with decrereasing temperature. Seeds showed little response to chloramphenicol at temperatures of 28°C and above except in the case of light treated Attractie seed. The failure of one batch of Grand Rapids seed to respond to chloramphenicol was associated with the low degree of dormancy in this batch.When the germination of half-seeds or intact excised embryos of Attractie seed was inhibited osmotically with 0.15 M NaCl a stimulatory response to chloramphenicol was obtained suggesting that the site of action was in the embryo itself.Other inhibitors of protein synthesis, cycloheximide, puromycin and p-fluorophenylalanine, did not stimulate germination. Cycloheximide at concentrations of 10 μg/ml and above inhibited germination whereas puromycin and p-fluorophenylalanine were relatively ineffective as germination inhibitors.

  20. Persistence of chloramphenicol residues in chicken muscle tissue after a therapeutic dose administration.

    PubMed

    Rejtharová, Martina; Rejthar, Libor; Bureš, Jiří; Vernerová, Eva; Hera, Alfred

    2017-04-01

    One-day-old chickens were individually orally treated with chloramphenicol at a dose of 100 mg per kg of body weight per day for three consecutive days. After the final treatment, the groups of six birds were sacrificed in seven-day intervals up to 42 days. The muscle tissue collected from the breasts and legs of each bird was individually examined for the presence of chloramphenicol residues using a GC/MS-NCI analytical method, which was validated according to Commission Decision 2002/657/EC. The decision limit (CCα) obtained for the method was 0.05 ng g(-1). The results showed a rapid decrease of chloramphenicol concentration in the muscle tissue after termination of the treatment, but also showed a relatively long persistence of low residue concentrations. Levels of chloramphenicol in muscle tissue averaged 64 ng g(-1) seven days after the final treatment and fell to 0.21 ng g(-1) after 35 days. All animals tested on the 35th day after the final treatment showed detectable chloramphenicol concentrations above the decision limit of the method used. No residues were detected in the animal tissues 42 days after the end of the treatment.

  1. A comparative study of epicillin and chloramphenicol in the treatment of enteric fever.

    PubMed

    Hassau, A; Sippel, J; Farid, Z; Tadros, S S; Brian, M

    1977-01-01

    One hundred patients with acute enteric fever were randomly assigned to treatment with either chloramphenicol 50 mg/kg body-weight or epicillin 1 g six hourly. Eighty-one patients had a positive blood culture for typhoid or paratyphoid bacilli and nineteen had a positive stool culture with a significant Widal titre. All fifty patients in the group treated with chloramphenicol responded, however there was one relapse with bacteraemia. In the group treated with epicillin, six from the total of fifty patients were considred treatment failures. Treatment was considred as a failure if the patient was febrile after ten days treatment or if there was a deterioration despite antibiotic therapy.

  2. Gatifloxacin versus chloramphenicol for uncomplicated enteric fever: an open-label, randomised, controlled trial

    PubMed Central

    Arjyal, Amit; Basnyat, Buddha; Koirala, Samir; Karkey, Abhilasha; Dongol, Sabina; Agrawaal, Krishna Kumar; Shakya, Nikki; Shrestha, Kabina; Sharma, Manish; Lama, Sanju; Shrestha, Kasturi; Khatri, Nely Shrestha; Shrestha, Umesh; Campbell, James I; Baker, Stephen; Farrar, Jeremy; Wolbers, Marcel; Dolecek, Christiane

    2011-01-01

    Summary Background We aimed to investigate whether gatifloxacin, a new generation and affordable fluoroquinolone, is better than chloramphenicol for the treatment of uncomplicated enteric fever in children and adults. Methods We did an open-label randomised superiority trial at Patan Hospital, Kathmandu, Nepal, to investigate whether gatifloxacin is more effective than chloramphenicol for treating uncomplicated enteric fever. Children and adults clinically diagnosed with enteric fever received either gatifloxacin (10 mg/kg) once a day for 7 days, or chloramphenicol (75 mg/kg per day) in four divided doses for 14 days. Patients were randomly allocated treatment (1:1) in blocks of 50, without stratification. Allocations were placed in sealed envelopes opened by the study physician once a patient was enrolled into the trial. Masking was not possible because of the different formulations and ways of giving the two drugs. The primary outcome measure was treatment failure, which consisted of at least one of the following: persistent fever at day 10, need for rescue treatment, microbiological failure, relapse until day 31, and enteric-fever-related complications. The primary outcome was assessed in all patients randomly allocated treatment and reported separately for culture-positive patients and for all patients. Secondary outcome measures were fever clearance time, late relapse, and faecal carriage. The trial is registered on controlled-trials.com, number ISRCTN 53258327. Findings 844 patients with a median age of 16 (IQR 9–22) years were enrolled in the trial and randomly allocated a treatment. 352 patients had blood-culture-confirmed enteric fever: 175 were treated with chloramphenicol and 177 with gatifloxacin. 14 patients had treatment failure in the chloramphenicol group, compared with 12 in the gatifloxacin group (hazard ratio [HR] of time to failure 0·86, 95% CI 0·40–1·86, p=0·70). The median time to fever clearance was 3·95 days (95% CI 3·68–4·68

  3. Electrochemical analysis of chloramphenicol using boron-doped diamond electrode applied to a flow-injection system.

    PubMed

    Chuanuwatanakul, Suchada; Chailapakul, Orawon; Motomizu, Shoji

    2008-04-01

    The electrochemical properties of chloramphenicol at a boron-doped diamond thin-film (BDD) electrode were studied using cyclic voltammetry. The highest current response of chloramphenicol was obtained with phosphate buffer, pH 6 (0.1 M) in 1% ethanol. The relationship between the concentration of chloramphenicol and the current response was linear over the range of 0.1-10 mM (R2=0.9990). The amount of chloramphenicol was analyzed by flow-injection analysis. A thin-layer flow cell equipped with a BDD electrode was used as an amperometric detector, and experiments were carried out at -0.7 V (vs. Ag/AgCl). The linear relationship between the current response and the concentration of chloramphenicol in the range of 0.1-50 microM (R2=0.9948) and the limit of detection of 0.03 microM (S/N=3) were obtained. This method has been successfully applied to the determination of chloramphenicol in sterile eye drops and milk sample by the standard addition method. The average recoveries of chloramphenicol in eye drops were 98.0%, and the average recoveries of chloramphenicol from spiked milk were 93.9-103%.

  4. An In Vitro Synergistic Interaction of Combinations of Thymus glabrescens Essential Oil and Its Main Constituents with Chloramphenicol

    PubMed Central

    Ilić, Budimir S.; Kocić, Branislava D.; Ćirić, Vojislav M.; Cvetković, Olga G.; Miladinović, Dragoljub L.

    2014-01-01

    The chemical composition and antibacterial activity of Thymus glabrescens Willd. (Lamiaceae) essential oil were examined, as well as the association between it and chloramphenicol. The antibacterial activities of geraniol and thymol, the main constituents of T. glabrescens oil, individually and in combination with chloramphenicol, were also determined. The interactions of the essential oil, geraniol, and thymol with chloramphenicol toward five selected strains were evaluated using the microdilution checkerboard assay in combination with chemometric methods. Oxygenated monoterpenes were the most abundant compound class in the oil, with geraniol (22.33%) as the major compound. The essential oil exhibited in vitro antibacterial activity against all tested bacterial strains, but the activities were lower than those of the standard antibiotic and thymol. A combination of  T. glabrescens oil and chloramphenicol produced a strong synergistic interaction (FIC indices in the range 0.21–0.87) and a substantial reduction of the MIC value of chloramphenicol, thus minimizing its adverse side effects. The combinations geraniol-chloramphenicol and thymol-chloramphenicol produced synergistic interaction to a greater extent, compared with essential oil-chloramphenicol association, which may indicate that the activity of the thyme oil could be attributed to the presence of significant concentrations of geraniol and thymol. PMID:24616649

  5. Responses of wild-type and resistant strains of the hyperthermophilic bacterium Thermotoga maritima to chloramphenicol challenge.

    PubMed

    Montero, Clemente I; Johnson, Matthew R; Chou, Chung-Jung; Conners, Shannon B; Geouge, Sarah G; Tachdjian, Sabrina; Nichols, Jason D; Kelly, Robert M

    2007-08-01

    Transcriptomes and growth physiologies of the hyperthermophile Thermotoga maritima and an antibiotic-resistant spontaneous mutant were compared prior to and following exposure to chloramphenicol. While the wild-type response was similar to that of mesophilic bacteria, reduced susceptibility of the mutant was attributed to five mutations in 23S rRNA and phenotypic preconditioning to chloramphenicol.

  6. Responses of Wild-Type and Resistant Strains of the Hyperthermophilic Bacterium Thermotoga maritima to Chloramphenicol Challenge▿ †

    PubMed Central

    Montero, Clemente I.; Johnson, Matthew R.; Chou, Chung-Jung; Conners, Shannon B.; Geouge, Sarah G.; Tachdjian, Sabrina; Nichols, Jason D.; Kelly, Robert M.

    2007-01-01

    Transcriptomes and growth physiologies of the hyperthermophile Thermotoga maritima and an antibiotic-resistant spontaneous mutant were compared prior to and following exposure to chloramphenicol. While the wild-type response was similar to that of mesophilic bacteria, reduced susceptibility of the mutant was attributed to five mutations in 23S rRNA and phenotypic preconditioning to chloramphenicol. PMID:17557852

  7. Applicational possibilities of linear and non-linear (polynomial) regressions and analysis of variance: kinetics of chloramphenicol.

    PubMed

    Arambasić, M B; Ristanović, D; Djordjević, A

    2002-01-01

    The dependance of the content and microbiological activity of Chloramphenicol (active substance) at dissolution on time and on pH, as well as that of the content and microbiological activity of Chloramphenicol (250 mg capsules) at release, on time, in in-vitro conditions, was determined using linear and non-linear (polynomial and generalized dilution) regressions. Based on the square error value, the dependance of the content and microbiological activity of Chloramphenicol (active substance) at dissolution on time and different pH values, as well as the dependance of the content and microbiological activity of Chloramphenicol (capsules) at release on time were best described by polynomial function. The comparison of the content and microbiological activity of Chloramphenicol (active substance) at dissolution at different pH values, as well as of Chloramphenicol (capsules) at release showed the significant correlation between these parameters (r = 0.999, P < 0.001). The comparision of the content, on one hand, and microbiological activity of Chloramphenicol (active substance), on the other, at dissolution at different pH values, as a function of time, was done using a modified method of one-way analysis of variance for linear regression comparisons. Based on the value of Fischer's coefficient (F), there is a statistically very significant difference between the contents and between the microbiological activities of chloramphenicol (active substance) at dissolution and different pH as a function of time (P < 0.005).

  8. Enhanced susceptibility of Escherichia coli to intracellular killing by human polymorphonuclear leukocytes after in vitro incubation with chloramphenicol.

    PubMed Central

    Pruul, H; Wetherall, B L; McDonald, P J

    1981-01-01

    The effect of brief exposure to chloramphenicol of a pathogenic strain of Escherichia coli on susceptibility to normal human leukocytes was examined. Leukocytes killed chloramphenicol-pretreated E. coli more efficiently than they did untreated controls. Phagocytosis of pretreated bacteria, as measured by the uptake of radiolabeled bacteria and by direct visual count of engulfed bacteria, was not significantly increased. The decrease in viability was associated with enhanced intracellular killing of phagocytosed antibiotic-damaged bacteria. Chloramphenicol pretreatment altered the frequency distribution of intracellular bacteria by decreasing the number of leukocytes containing multiple stainable bacteria. Leukocytes failed to kill chloramphenicol-pretreated E. coli in the presence of phenylbutazone, which allowed an accumulation of intracellular bacteria. These results indicate that exposure of E. coli to chloramphenicol renders the bacteria more susceptible to intracellular killing and degradation. PMID:7023384

  9. In vitro activity of chloramphenicol, florfenicol and enrofloxacin against Chlamydia pecorum isolated from koalas (Phascolarctos cinereus).

    PubMed

    Black, L A; Higgins, D P; Govendir, M

    2015-11-01

    To determine the in vitro susceptibilities of koala isolates of Chlamydia pecorum to enrofloxacin and chloramphenicol, which are frequently used to treat koalas with chlamydiosis, and florfenicol, a derivative of chloramphenicol. The in vitro susceptibilities were determined by culturing three stored isolates and seven clinical swabs of C. pecorum. Susceptibility testing was undertaken using cycloheximide-treated buffalo green monkey kidney cells in 96 well microtitre plates. The minimum inhibitory concentrations (MICs) for all isolates were 0.25-0.50 µg/mL (enrofloxacin), 1-2 µg/mL (chloramphenicol), and 1-2 µg/mL (florfenicol). Minimum bactericidal concentration (MBC) values for five isolates were also determined and were within one two-fold dilution of MICs. The MICs and MBCs of these antimicrobials were within ranges previously reported for other chlamydial species. When combined with previously published pharmacokinetic data, the in vitro susceptibility results support chloramphenicol as a more appropriate treatment option than enrofloxacin for koalas with chlamydiosis. The susceptibility results also indicate florfenicol may be an appropriate treatment option for koalas with chlamydiosis, warranting further investigation. © 2015 Australian Veterinary Association.

  10. Involvement of the Efflux Pumps in Chloramphenicol Selected Strains of Burkholderia thailandensis: Proteomic and Mechanistic Evidence

    PubMed Central

    Biot, Fabrice V.; Valade, Eric; Garnotel, Eric; Chevalier, Jacqueline; Villard, Claude; Thibault, François M.; Vidal, Dominique R.; Pagès, Jean-Marie

    2011-01-01

    Burkholderia is a bacterial genus comprising several pathogenic species, including two species highly pathogenic for humans, B. pseudomallei and B. mallei. B. thailandensis is a weakly pathogenic species closely related to both B. pseudomallei and B. mallei. It is used as a study model. These bacteria are able to exhibit multiple resistance mechanisms towards various families of antibiotics. By sequentially plating B. thailandensis wild type strains on chloramphenicol we obtained several resistant variants. This chloramphenicol-induced resistance was associated with resistance against structurally unrelated antibiotics including quinolones and tetracyclines. We functionally and proteomically demonstrate that this multidrug resistance phenotype, identified in chloramphenicol-resistant variants, is associated with the overexpression of two different efflux pumps. These efflux pumps are able to expel antibiotics from several families, including chloramphenicol, quinolones, tetracyclines, trimethoprim and some β-lactams, and present a partial susceptibility to efflux pump inhibitors. It is thus possible that Burkholderia species can develop such adaptive resistance mechanisms in response to antibiotic pressure resulting in emergence of multidrug resistant strains. Antibiotics known to easily induce overexpression of these efflux pumps should be used with discernment in the treatment of Burkholderia infections. PMID:21347382

  11. DIFFERENTIATION AND FUNCTIONAL EXPRESSION OF POTENTIAL ANTIBODY-PRODUCING CELLS IN THE PRESENCE OF CHLORAMPHENICOL

    PubMed Central

    Schoenberg, Melvin D.; Moore, Richard D.; Weisberger, Austin S.

    1967-01-01

    Rabbits were immunized with diphtheria toxoid combined with complete Freund's adjuvant. Half of the animals were started on intramuscular injections of chloramphenicol 24 hr before the injection of the antigens. There was a general depression of protein synthesis in the immune system in the presence of chloramphenicol, but a greater effect on the synthesis of antibody than on the synthesis of proteins necessary for reproduction and maturation. In contrast to the finding of antibody in cells of the spleen and in the circulation of the control animals, those animals receiving chloramphenicol did not have measurable circulating antibody, and their spleens contained only a few cells with intracytoplasmic antibody late in the course of the experiment. Cytologically there was maturation of potential antibody-producing cells in the red pulp and nonfollicular white pulp of the spleen while the animals were receiving chloramphenicol. These cells developed more slowly, and were fewer and smaller than those of the control animals. They had numerous small, electron-opaque particles in their cytoplasm early in development. Ribosomes were synthesized, though fewer in number. The endoplasmic reticulum formed more slowly. PMID:10976231

  12. Adverse events associated with chloramphenicol use in dogs: a retrospective study (2007-2013).

    PubMed

    Short, J; Zabel, S; Cook, C; Schmeitzel, L

    2014-11-29

    Chloramphenicol is a broad spectrum antibiotic that has been increasingly utilised since the emergence of methicillin-resistant staphylococcal infections. Due to toxicities in humans, use of the drug has been limited. In dogs, gastrointestinal signs are common adverse events described, and bone marrow suppression is possible. The aim of this study was to evaluate the adverse events associated with chloramphenicol in dogs seen by one specialty practice from January 2007 through June 2013. The database was searched for all dogs prescribed chloramphenicol during the time period. Dosage, length of treatment, age and body weight of the dogs were recorded as well as any adverse events that occurred during treatment. A total of 105 cases were evaluated. Thirty-nine dogs experienced at least one adverse event while on the medication. The most commonly noted were gastrointestinal signs and hindlimb weakness. The mean body weight for dogs with hindlimb weakness was 35.3 kg, which was significant. Resolution was documented in 54 per cent of cases when the drug was discontinued. Methicillin-resistant Staphylococcus pseudintermedius on bacterial culture was listed as the reason for chloramphenicol use in 76 per cent of the cases. Based on this information, further prospective studies are recommended to evaluate the reproducibility of this report.

  13. Determination of assay and impurities of gamma irradiated chloramphenicol in eye ointment.

    PubMed

    Hong, L; Altorfer, H

    2001-02-01

    A sample preparation method was developed to isolate chloramphenicol and its radiolytic products from an oily ointment base. The isolation method suspended the eye ointment in n-hexane at 45 degrees C, and isolated the target compounds as residue by centrifugation. It was found that the main element to ensure a satisfactory isolation was keeping the sample solution at 45 degrees C during sample preparation. Linearity, precision, accuracy and suitability of the method were confirmed valid for both assay and impurity tests. This isolation method was ideal for assay, unique for extraction of unexpected and complex radiolysis products, and had a number of advantages compared to the pretreatment methods described in The United Stares Pharmacopoeia and British Pharmacopoeia, in terms of accuracy, precision, and easy handling. The effect of gamma-irradiation on chloramphenicol eye ointment was studied by HPLC, after applying the developed sample preparation method. The present assay and impurity test methods with HPLC were confirmed to be suitable for irradiated chloramphenicol in eye ointment. Formation of radiolytic products induced by gamma-irradiation was evidenced by the impurity test. The assay test showed that active ingredient of chloramphenicol eye ointment decreased by 3.3% at an irradiation dose of 25 kGy and by 11.1% at 50 kGy.

  14. The toxic effects of monensin and chloramphenicol on laying turkey breeder hens.

    PubMed

    Friedman, Y; Weisman, Y; Avidar, Y; Bogin, E

    1998-01-01

    A case report of choramphenicol and monensin poisoning in turkey breeder hens is presented in which anorexia and a fall in egg production were features. An experiment study was then conducted in turkey breeding hens given increasing levels of monensin and chloramphenicol singly or in combination. Monensin fed at levels of 42 or 85 ppm had no adverse effect on egg production but chloramphenicol in the drinking water at 500 mg/l for 4 days caused a 9.2% fall in egg production compared to control untreated birds. When 500 mg/l chloramphenicol and 42 ppm monensin were given together for 8 days there was lameness, 12% mortality, but no drop in egg production. When 70 ppm monensin and 500 mg/l chloramphenicol were given together for 4 days, 14 of 22 birds died and egg production in the remainder ceased. Withdrawal of monensin arrested mortality but egg production did not recover. Serum creatine phosphokinase levels in this group were 20 times greater than those of the controls and were similar to birds studied in the case report.

  15. 21 CFR 524.390d - Chloramphenicol-prednisolone ophthalmic ointment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.390d Chloramphenicol-prednisolone ophthalmic ointment. (a) Specifications. Each gram... with other antibiotics, prolonged use may result in overgrowth of nonsusceptible organisms....

  16. Analysis of conjugation of chloramphenicol and hemoglobin by fluorescence, circular dichroism and molecular modeling

    NASA Astrophysics Data System (ADS)

    Ding, Fei; Liu, Wei; Sun, Ye; Yang, Xin-Ling; Sun, Ying; Zhang, Li

    2012-01-01

    Chloramphenicol is a low cost, broad spectrum, highly active antibiotic, and widely used in the treatment of serious infections, including typhoid fever and other life-threatening infections of the central nervous system and respiratory tract. The purpose of the present study was to examine the conjugation of chloramphenicol with hemoglobin (Hb) and compared with albumin at molecular level, utilizing fluorescence, UV/vis absorption, circular dichroism (CD) as well as molecular modeling. Fluorescence data indicate that drug bind Hb generate quenching via static mechanism, this corroborates UV/vis absorption measurements that the ground state complex formation with an affinity of 10 4 M -1, and the driving forces in the Hb-drug complex are hydrophilic interactions and hydrogen bonds, as derived from computational model. The accurate binding site of drug has been identified from the analysis of fluorescence and molecular modeling, α1β2 interface of Hb was assigned to possess high-affinity for drug, which located at the β-37 Trp nearby. The structural investigation of the complexed Hb by synchronous fluorescence, UV/vis absorption, and CD observations revealed some degree of Hb structure unfolding upon complexation. Based on molecular modeling, we can draw the conclusion that the binding affinity of drug with albumin is superior, compared with Hb. These phenomena can provide salient information on the absorption, distribution, pharmacology, and toxicity of chloramphenicol and other drugs which have analogous configuration with chloramphenicol.

  17. Estimation of the chloramphenicol and cycloheximide inhibition of protein synthesis in brain cholinergic synaptosomes.

    PubMed

    Corbaton, V; Muiño, M T; Fernández-Silva, P; López-Pérez, M J; Montoya, J

    1991-03-15

    Cholinergic synaptosomes have been prepared from sheep brain cortex by means of an immunoaffinity method using a specific anti-(Chol I) antiserum. The [14C]leucine incorporation into proteins of this preparation shows a low cycloheximide and a high chloramphenicol sensitivity. This fact suggests that the mitochondrial protein synthesis system is the only one present in this fraction.

  18. 75 FR 55810 - Withdrawal of Approval of New Animal Drug Applications; Chloramphenicol, Lincomycin, Pyrantel...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Withdrawal of Approval of New Animal Drug Applications; Chloramphenicol, Lincomycin, Pyrantel Tartrate, and Tylosin Phosphate and Sulfamethazine AGENCY: Food and Drug...

  19. Plasma concentrations of chloramphenicol after subcutaneous administration to koalas (Phascolarctos cinereus) with chlamydiosis.

    PubMed

    Govendir, M; Hanger, J; Loader, J J; Kimble, B; Griffith, J E; Black, L A; Krockenberger, M B; Higgins, D P

    2012-04-01

    Nine mature koalas with chlamydiosis, typically keratoconjunctivitis and/or urogenital tract infection, were treated with daily subcutaneous injections of chloramphenicol at 60 mg/kg for 45 days (five koalas), or for a shorter duration (four koalas). All koalas were initially positive for Chlamydia pecorum as determined by real-time polymerase chain reaction (qPCR). Plasma chloramphenicol concentrations were determined at t = 0, 1, 2, 4, 8, and 24 h after the day 1 injection (nine koalas) and after the day 15 injection (seven koalas). Chloramphenicol reached a median (and range) maximum plasma concentration of 3.03 (1.32-5.03 μg/mL) at 4 (1-8 h) after the day 1 injection and 4.82 (1.97-27.55 μg/mL) at 1 (1-2 h) after day 15. The median (and range) of AUC(0-24) on day 1 and day 15 were 48.14 (22.37-81.14 μg·h/mL) and 50.83 (28.43-123.99 μg·h/mL), respectively. The area under the moment curve (AUMC)(0-24) median (and range) for day 1 and day 15 were 530.03 (233.05-798.97 h) and 458.15 (291.72-1093.58 h), respectively. Swabs were positive for chlamydial DNA pretreatment, and all koalas except one, produced swabs negative for chlamydial DNA during treatment and which remained so, for 2-63 days after treatment, however whether chloramphenicol treatment prevented long-term recrudescence of infection was not established. At this dose and dosing frequency, chloramphenicol appeared to control mild chlamydial infection and prevent shedding, but severe urogenital disease did not appear to respond to chloramphenicol at this dosage regime. For koalas affected by severe chlamydiosis, antibiotics alone are not sufficient to effect a cure, possibly because of structural or metabolic changes associated with chronic disease and inflammation. © 2011 Blackwell Publishing Ltd.

  20. Determination of chloramphenicol residues in shrimps by liquid chromatography-mass spectrometry.

    PubMed

    Ramos, M; Muñoz, P; Aranda, A; Rodriguez, I; Diaz, R; Blanca, J

    2003-07-05

    A liquid chromatographic method with mass spectrometric detection and identification (LC-MS) is presented for the determination of chloramphenicol (CAP) in shrimp tissues. Homogenized shrimp samples were extracted with phosphate buffer (pH 7.0). Clean-up was carried out on a C(18) SPE cartridge. Chloramphenicol was determined by LC-MS-ESI in negative mode. The column used was a Symmetry Shield with a mixture of acetonitrile-water (25:75) as mobile phase. Shrimp samples were fortified at CAP levels between 0.2 and 50 ng g(-1) with 5D-CAP as internal standard. At these levels, accuracies lay between 101 and 110% and between-day reproducibilities were lower than 7.1%, expressed as the variation coefficient of the mean. Limit of decision (CCalpha) was 0.02 ng g(-1). Limit of quantitation (LOQ) was 0.2 ng g(-1).

  1. Erythromycin- and chloramphenicol-induced ribosomal assembly defects are secondary effects of protein synthesis inhibition.

    PubMed

    Siibak, Triinu; Peil, Lauri; Xiong, Liqun; Mankin, Alexander; Remme, Jaanus; Tenson, Tanel

    2009-02-01

    Several protein synthesis inhibitors are known to inhibit ribosome assembly. This may be a consequence of direct binding of the antibiotic to ribosome precursor particles, or it could result indirectly from loss of coordination in the production of ribosomal components due to the inhibition of protein synthesis. Here we demonstrate that erythromycin and chloramphenicol, inhibitors of the large ribosomal subunit, affect the assembly of both the large and small subunits. Expression of a small erythromycin resistance peptide acting in cis on mature ribosomes relieves the erythromycin-mediated assembly defect for both subunits. Erythromycin treatment of bacteria expressing a mixture of erythromycin-sensitive and -resistant ribosomes produced comparable effects on subunit assembly. These results argue in favor of the view that erythromycin and chloramphenicol affect the assembly of the large ribosomal subunit indirectly.

  2. Structural, electronic, thermodynamical and charge transfer properties of Chloramphenicol Palmitate using vibrational spectroscopy and DFT calculations

    NASA Astrophysics Data System (ADS)

    Mishra, Rashmi; Srivastava, Anubha; Sharma, Anamika; Tandon, Poonam; Baraldi, Cecilia; Gamberini, Maria Christina

    2013-01-01

    The global problem of advancing bacterial resistance to newer drugs has led to renewed interest in the use of Chloramphenicol Palmitate (C27H42Cl2N2O6) [Palmitic acid alpha ester with D-threo-(-),2-dichloro-N-(beta-hydroxy-alpha-(hydroxymethyl)-p-nitrophenethyl)acetamide also known as Detereopal]. The characterization of the three polymorphic forms of Chloramphenicol Palmitate (CPP) was done spectroscopically by employing FT-IR and FT-Raman techniques. The equilibrium geometry, various bonding features, and harmonic wavenumbers have been investigated for most stable form A with the help of DFT calculations and a good correlation was found between experimental data and theoretical values. Electronic properties have been analyzed employing TD-DFT for both gaseous and solvent phase. The theoretical calculation of thermodynamical properties along with NBO analysis has also been performed to have a deep insight into the molecule for further applications.

  3. The effect of ethidium bromide and chloramphenicol on mitochondrial biogenesis in primary human fibroblasts

    SciTech Connect

    Kao, Li-Pin; Ovchinnikov, Dmitry; Wolvetang, Ernst

    2012-05-15

    The expression of mitochondrial components is controlled by an intricate interplay between nuclear transcription factors and retrograde signaling from mitochondria. The role of mitochondrial DNA (mtDNA) and mtDNA-encoded proteins in mitochondrial biogenesis is, however, poorly understood and thus far has mainly been studied in transformed cell lines. We treated primary human fibroblasts with ethidium bromide (EtBr) or chloramphenicol for six weeks to inhibit mtDNA replication or mitochondrial protein synthesis, respectively, and investigated how the cells recovered from these insults two weeks after removal of the drugs. Although cellular growth and mitochondrial gene expression were severely impaired after both inhibitor treatments we observed marked differences in mitochondrial structure, membrane potential, glycolysis, gene expression, and redox status between fibroblasts treated with EtBr and chloramphenicol. Following removal of the drugs we further detected clear differences in expression of both mtDNA-encoded genes and nuclear transcription factors that control mitochondrial biogenesis, suggesting that the cells possess different compensatory mechanisms to recover from drug-induced mitochondrial dysfunction. Our data reveal new aspects of the interplay between mitochondrial retrograde signaling and the expression of nuclear regulators of mitochondrial biogenesis, a process with direct relevance to mitochondrial diseases and chloramphenicol toxicity in humans. -- Highlights: ► Cells respond to certain environmental toxins by increasing mitochondrial biogenesis. ► We investigated the effect of Chloramphenicol and EtBr in primary human fibroblasts. ► Inhibiting mitochondrial protein synthesis or DNA replication elicit different effects. ► We provide novel insights into the cellular responses toxins and antibiotics.

  4. Dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities.

    PubMed

    Yan, Hu; Wang, Dandan; Dong, Bin; Tang, Feifan; Wang, Baichuan; Fang, Hua; Yu, Yunlong

    2011-07-01

    The dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities were investigated. The results revealed that carbendazim dissipation was little affected by chloramphenicol, whereas chloramphenicol dissipation was found to be retarded significantly by the presence of carbendazim. The inhibitory effect of carbendazim on the fungal:bacterial ratios was increased by the presence of chloramphenicol, and the inhibitory effect of chloramphenicol on neutral phosphatase was increased by the presence of carbendazim. Carbendazim increased soil catalase and urease activities, but this increase was partially diminished by the presence of chloramphenicol. Little interaction was observed between carbendazim and chloramphenicol with regard to their influence on soil invertase. The results obtained in this study suggest that combinations of fungicides and antibiotics may alter the compounds' individual behaviors in soil and their effects on soil enzymes.

  5. Simultaneous Chloramphenicol and Florfenicol Determination by A Validated DLLME-HPLC-UV Method in Pasteurized Milk.

    PubMed

    Karami-Osboo, Rouhollah; Miri, Ramin; Javidnia, Katayoun; Kobarfard, Farzad

    2016-01-01

    The antibiotic residues in milk are a well-known serious problem and pose several health hazards to consumers. We have described a simple, rapid, and inexpensive DLLME-HPLC/UV technique for the extraction of chloramphenicol and florfenicol residues in milk samples. Under the optimum conditions, linearity of the method was observed over the range 0.02-0.85 µg/L with correlation coefficients > 0.999. The proposed method has been found to have a good limit of detection (signal to noise ratio = 3) for chloramphenicol (12.5 µg/Kg) and florfenicol (12.2 µg/Kg), and precision with relative standard deviation values under 15% (RSD, n = 3). Good recoveries (69.1-79.4%) were obtained for the extraction of the target analytes in milk samples. This simple and economic method has been applied for analyses of 15 real milk samples. Among all samples only one of them was contaminated to florfenicol; 62.4 µg/Kg and contamination to chloramphenicol was not detected.

  6. Liquid chromatographic determination of multiple sulfonamides, nitrofurans, and chloramphenicol residues in pasteurized milk.

    PubMed

    Perez, Norma; Gutierrez, Rey; Noa, Mario; Diaz, Gilberto; Luna, Hector; Escobar, Irma; Munive, Zenaida

    2002-01-01

    A rapid and selective liquid chromatographic method was developed to detect 6 sulfonamides, 3 nitrofurans, and chloramphenicol residues in pasteurized milk. The 10 drugs were extracted with chloroform-acetone and the organic phase was evaporated; the residues were dissolved in an aqueous sodium acetate buffer solution 0.02M (pH = 4.8), and the fat was removed by washing with hexane. The aqueous layer was collected, filtered, and injected. The 6 sulfonamides and chloramphenicol were detected at 275 nm ultraviolet (UV) using a gradient system starting with sodium acetate buffer solution-acetonitrile (95 + 5) and finishing with sodium acetate buffer solution-acetonitrile (80 + 20). Nitrofurans were detected at 375 nm (UV) isocratically with sodium acetate buffer solution-acetonitrile (80 + 20). For 50 ppb fortified milk, the average recoveries were (sulfathiazole) 65.52%; (sulfamerazine) 75.36%; (sulfamethazine) 93.94%; (sulfachlorpyridazine) 75.94%; (sulfamethoxazole) 85.18%; (sulfamonomethoxine) 83.45%; (chloramphenicol) 104.17%; (nitrofurazone) 91.81%; (furazolidone) 100.76%; and (furaltadone) 72.38%. Method detection limits ranged from 4 ppb (nitrofurazone) to 16 ppb (sulfamethazine). Some matrix interferences (3-7 ppb) were observed only with sulfonamides.

  7. In vitro comparison of ampicillin-chloramphenicol and ampicillin-cefotaxime against 284 Haemophilus isolates.

    PubMed Central

    Lapointe, J R; Lavallée, C; Michaud, A; Chicoine, L; Joncas, J H

    1986-01-01

    Since November 1982 at the Sainte-Justine Hospital in Montreal, ampicillin and cefotaxime were used in association as initial treatment (greater than or equal to 48 h) for childhood bacterial meningitis. In this report is described the in vitro interaction of the new regimen in comparison with that of the previous ampicillin-chloramphenicol combination against 284 Haemophilus isolates. Among the 156 ampicillin-susceptible, beta-lactamase-negative isolates, synergy was detected in 13 with ampicillin-cefotaxime, and antagonism was detected in only 1; in contrast, synergy was found in only 2 strains with ampicillin-chloramphenicol, and antagonism was found in 15. These differences were statistically significant (P less than 0.01). Such significant differences were not observed among the 128 ampicillin-resistant, beta-lactamase-positive Haemophilus isolates. The synergy of ampicillin-cefotaxime did not contribute to a decrease of the MIC of cefotaxime for 90% of isolates tested, whereas the antagonism of ampicillin-chloramphenicol did not contribute to increase the MIC of ampicillin for 90% of isolates tested. PMID:3486630

  8. Susceptibility of Haemophilus influenzae to chloramphenicol and eight beta-lactam antibiotics.

    PubMed Central

    Thirumoorthi, M C; Kobos, D M; Dajani, A S

    1981-01-01

    We examined the minimal inhibitory concentrations and minimal bactericidal concentrations of chloramphenicol, ampicillin, ticarcillin, cefamandole, cefazolin, cefoxitin, cefotaxime, ceforanide, and moxalactam for 100 isolates of Haemophilus influenzae, 25 of which produced beta-lactamase. Susceptibility was not influenced by the capsular characteristic of the organism. The mean minimal inhibitory concentrations of cefamandole, ticarcillin, and ampicillin for beta-lactamase-producing strains were 3-, 120-, and 400-fold higher than their respective mean minimal inhibitory concentrations for beta-lactamase-negative strains. No such difference was noted for the other antibiotics. We performed time-kill curve studies, using chloramphenicol, ampicillin, cefamandole, cefotaxime, and moxalactam with two concentrations of the antimicrobial agents (4 or 20 times the minimal inhibitory concentrations) and two inoculum sizes (10(4) or 10(6) colony-forming units per ml). The inoculum size had no appreciable effect on the rate of killing of beta-lactamase-negative strains. The rates at which beta-lactamase-producing strains were killed by chloramphenicol, cefotaxime, and moxalactam was not influenced by the inoculum size. Whereas cefamandole in high concentrations was able to kill at 10(6) colony-forming units/ml of inoculum, it had only a temporary inhibiting effect at low drug concentrations. Methicillin and the beta-lactamase inhibitor CP-45,899 were able to neutralize the inactivation of cefamandole by a large inoculum of beta-lactamase-producing H. influenzae. PMID:6974541

  9. Two Distinct Major Facilitator Superfamily Drug Efflux Pumps Mediate Chloramphenicol Resistance in Streptomyces coelicolor▿

    PubMed Central

    Vecchione, James J.; Alexander, Blair; Sello, Jason K.

    2009-01-01

    Chloramphenicol, florfenicol, and thiamphenicol are used as antibacterial drugs in clinical and veterinary medicine. Two efflux pumps of the major facilitator superfamily encoded by the cmlR1 and cmlR2 genes mediate resistance to these antibiotics in Streptomyces coelicolor, a close relative of Mycobacterium tuberculosis. The transcription of both genes was observed by reverse transcription-PCR. Disruption of cmlR1 decreased the chloramphenicol MIC 1.6-fold, while disruption of cmlR2 lowered the MIC 16-fold. The chloramphenicol MIC of wild-type S. coelicolor decreased fourfold and eightfold in the presence of reserpine and Phe-Arg-β-naphthylamide, respectively. These compounds are known to potentiate the activity of some antibacterial drugs via efflux pump inhibition. While reserpine is known to potentiate drug activity against gram-positive bacteria, this is the first time that Phe-Arg-β-naphthylamide has been shown to potentiate drug activity against a gram-positive bacterium. PMID:19687245

  10. Simultaneous Chloramphenicol and Florfenicol Determination by A Validated DLLME-HPLC-UV Method in Pasteurized Milk

    PubMed Central

    Karami-Osboo, Rouhollah; Miri, Ramin; Javidnia, Katayoun; Kobarfard, Farzad

    2016-01-01

    The antibiotic residues in milk are a well-known serious problem and pose several health hazards to consumers. We have described a simple, rapid, and inexpensive DLLME-HPLC/UV technique for the extraction of chloramphenicol and florfenicol residues in milk samples. Under the optimum conditions, linearity of the method was observed over the range 0.02-0.85 µg/L with correlation coefficients > 0.999. The proposed method has been found to have a good limit of detection (signal to noise ratio = 3) for chloramphenicol (12.5 µg/Kg) and florfenicol (12.2 µg/Kg), and precision with relative standard deviation values under 15% (RSD, n = 3). Good recoveries (69.1–79.4%) were obtained for the extraction of the target analytes in milk samples. This simple and economic method has been applied for analyses of 15 real milk samples. Among all samples only one of them was contaminated to florfenicol; 62.4 µg/Kg and contamination to chloramphenicol was not detected. PMID:27980571

  11. Novel mechanism of resistance to oxazolidinones, macrolides, and chloramphenicol in ribosomal protein L4 of the pneumococcus.

    PubMed

    Wolter, Nicole; Smith, Anthony M; Farrell, David J; Schaffner, William; Moore, Matthew; Whitney, Cynthia G; Jorgensen, James H; Klugman, Keith P

    2005-08-01

    Two clinical Streptococcus pneumoniae isolates, identified as resistant to macrolides and chloramphenicol and nonsusceptible to linezolid, were found to contain 6-bp deletions in the gene encoding riboprotein L4. The gene transformed susceptible strain R6 so that it exhibited such resistance, with the transformants also showing a fitness cost. We demonstrate a novel bacterial mechanism of resistance to chloramphenicol and nonsusceptibility to linezolid.

  12. Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

    PubMed

    Samanidou, Victoria; Kehagia, Maria; Kabir, Abuzar; Furton, Kenneth G

    2016-03-31

    Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol-gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol-gel MIP was 23 mg/g. The sol-gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work-flow. Intra and

  13. Phenytoin pharmacokinetics and clinical effects in African children following fosphenytoin and chloramphenicol coadministration.

    PubMed

    Ogutu, Bernhards R; Newton, Charles R J C; Muchohi, Simon N; Otieno, Godfrey O; Kokwaro, Gilbert O

    2002-12-01

    Some children with malaria and convulsions also have concurrent bacterial meningitis. Chloramphenicol is used to treat the latter whereas phenytoin is used for convulsions. Since chloramphenicol inhibits the metabolism of phenytoin in vivo, we studied the effects of chloramphenicol on phenytoin pharmacokinetics in children with malaria. Multiple intravenous (i.v.) doses of chloramphenicol succinate (CAP) (25 mg kg-1 6 hourly for 72 h) and a single intramuscular (i.m.) seizure prophylactic dose of fosphenytoin (18 mg kg-1 phenytoin sodium equivalents) were concomitantly administered to 15 African children with malaria. Control children (n = 13) with malaria received a similar dose of fosphenytoin and multiple i.v. doses (25 mg kg-1 8 hourly for 72 h) of cefotaxime (CEF). Blood pressure, heart rate, respiratory rate, oxygen saturation, level of consciousness and convulsion episodes were monitored. Cerebrospinal fluid (CSF) and plasma phenytoin concentrations were determined. The area under the plasma unbound phenytoin concentration-time curve (AUC(0, infinity ); means (CAP, CEF): 58.5, 47.6 micro g ml-1 h; 95% CI for difference between means: -35.0, 11.4), the peak unbound phenytoin concentrations (Cmax; medians: 1.12, 1.29 micro g ml-1; 95% CI: -0.5, 0.04), the times to Cmax (tmax; medians: 4.0, 4.0 h; 95% CI: -2.0, 3.7), the CSF:plasma phenytoin ratios (means: 0.21, 0.22; 95% CI: -0.8, 0.10), the fraction of phenytoin unbound (means: 0.06, 0.09; 95% CI: -0.01, 0.07) and the cardiovascular parameters were not significantly different between CAP and CEF groups. However, mean terminal elimination half-life (t1/2,z) was significantly longer (23.7, 15.5 h; 95% CI: 1.71, 14.98) in the CAP group compared with the CEF group. Seventy per cent of the children had no convulsions during the study period. Concomitant administration of chloramphenicol and a single i.m. dose of fosphenytoin alters the t1/2,z but not the other pharmacokinetic parameters or clinical effects of

  14. Degradation of Oxytetracycline, Streptomycin, Sulphathiazole and Chloramphenicol Residues in Different Types of Honey.

    PubMed

    Gačić, Milica; Bilandžić, Nina; Šipušić, Đurđica Ivanec; Petrović, Marinko; Kos, Blaženka; Vahčić, Nada; Šušković, Jagoda

    2015-06-01

    Some of the most frequently used antibiotics in apiculture for the treatment of bacterial brood diseases are oxytetracycline, chloramphenicol, sulphathiazole and streptomycin. Therefore, the aim of this research is to determine the degradation kinetics of the residua these antibiotics leave behind in different types of honey stored in dark at 25 °C. The examined honey samples (N=74) originating from the Croatian market had satisfactory physicochemical properties and pollen characteristics. Quantitative analyses of antibiotic residues were done using HPLC and ELISA methods. No antibiotic residues were found in any of the tested acacia, chestnut, floral, meadow and honeydew honey samples (N=74). In the next step, each of the tested honey samples was supplemented with one of the following antibiotics (in mg/kg): oxytetracycline 10, chloramphenicol 200, sulphathiazole 200 or streptomycin 0.5. Relatively high mass fractions of antibiotics have been added to the honey because the stability of each antibiotic is highly dependent on the spiked antibiotic mass fraction and also on its chemical structure. During a 6-month storage in the dark at 25 °C, the dynamics of degradation of the studied antibiotics was proven to differ dependent on the type of honey into which the antibiotic was added. The half-life of oxytetracycline in the acacia, floral, meadow and honeydew honey stored in the dark at 25 °C was 15, 16, 17 and 19 days, respectively, while in the chestnut honey the decomposition failed to be seen even after 60 days of storage. In all examined honey samples, the half-life of chloramphenicol and sulphathiazole was proven to be longer than 6 months. The fastest decomposition was seen of oxytetracycline added into the acacia honey, followed by streptomycin and sulphathiazole added into the same, while the longest decomposition delay was seen when chloramphenicol was added into the floral honey. According to the results obtained using a linear model of degradation

  15. Degradation of Oxytetracycline, Streptomycin, Sulphathiazole and Chloramphenicol Residues in Different Types of Honey

    PubMed Central

    Gačić, Milica; Bilandžić, Nina; Šipušić, Đurđica Ivanec; Petrović, Marinko; Vahčić, Nada; Šušković, Jagoda

    2015-01-01

    Summary Some of the most frequently used antibiotics in apiculture for the treatment of bacterial brood diseases are oxytetracycline, chloramphenicol, sulphathiazole and streptomycin. Therefore, the aim of this research is to determine the degradation kinetics of the residua these antibiotics leave behind in different types of honey stored in dark at 25 °C. The examined honey samples (N=74) originating from the Croatian market had satisfactory physicochemical properties and pollen characteristics. Quantitative analyses of antibiotic residues were done using HPLC and ELISA methods. No antibiotic residues were found in any of the tested acacia, chestnut, floral, meadow and honeydew honey samples (N=74). In the next step, each of the tested honey samples was supplemented with one of the following antibiotics (in mg/kg): oxytetracycline 10, chloramphenicol 200, sulphathiazole 200 or streptomycin 0.5. Relatively high mass fractions of antibiotics have been added to the honey because the stability of each antibiotic is highly dependent on the spiked antibiotic mass fraction and also on its chemical structure. During a 6-month storage in the dark at 25 °C, the dynamics of degradation of the studied antibiotics was proven to differ dependent on the type of honey into which the antibiotic was added. The half-life of oxytetracycline in the acacia, floral, meadow and honeydew honey stored in the dark at 25 °C was 15, 16, 17 and 19 days, respectively, while in the chestnut honey the decomposition failed to be seen even after 60 days of storage. In all examined honey samples, the half-life of chloramphenicol and sulphathiazole was proven to be longer than 6 months. The fastest decomposition was seen of oxytetracycline added into the acacia honey, followed by streptomycin and sulphathiazole added into the same, while the longest decomposition delay was seen when chloramphenicol was added into the floral honey. According to the results obtained using a linear model of

  16. Chromatographic evaluation of polymers imprinted with analogs of chloramphenicol and application to selective solid-phase extraction.

    PubMed

    Schirmer, Christina; Meisel, Hans

    2009-08-01

    To obtain a highly selective material for the antibiotic chloramphenicol, which has several harmful side effects in humans, different molecularly imprinted polymers (MIPs) were prepared. In order to avoid a major traditional drawback associated with MIPs of residual template bleeding, molecules that are structurally related to chloramphenicol were used as templates for polymer synthesis. Chromatographic evaluation indicated that the employed template imparted a significant influence on the recognition properties of the corresponding polymer. A strong retention of chloramphenicol under nonpolar elution conditions (k = 68.03, IF = 17.72) and under aqueous elution conditions (k = 92.44, IF = 1.35) was achieved. After chromatographic evaluation, the MIP was utilized as the recognition sorbent in a solid-phase extraction to determine chloramphenicol using either an organic or aqueous washing solvent. Recoveries of nearly 100% from the chloramphenicol standard solution and nearly 90% from honey samples spiked with chloramphenicol were attained. Furthermore, the applicability of the MIP for sample cleanup was demonstrated.

  17. Development of LC-MS/MS methodology for the detection/determination and confirmation of chloramphenicol, chloramphenicol 3-O-β-d-glucuronide, florfenicol, florfenicol amine and thiamphenicol residues in bovine, equine and porcine liver.

    PubMed

    Fedeniuk, Rick W; Mizuno, Massey; Neiser, Connie; O'Byrne, Collin

    2015-06-01

    A method for the detection and confirmation of organic solvent extractable residues of the neutral, acidic, and basic analytes of the amphenicol class veterinary drugs and selected metabolites was developed and validated. Using a modified QuEChERS extraction with SPE cleanup and LC-MS/MS analysis, limits of detection and confirmation for the different analytes in bovine, equine, and porcine liver ranged from 0.1ng/g for chloramphenicol to 1ng/g for florfenicol amine. Tissue homogenization with an ammonium formate/EDTA solution and subsequent analyte partitioning against 7:3 acetonitrile:isopropanol solution and mixed-mode strong-cation exchange solid-phase extraction cartridge cleanup allowed for the extraction of all compounds from tissues with mean recoveries ranging from 50% (chloramphenicol 3-O-β-d-glucuronide) to 90% (thiamphenicol). Matrix effects ranged from greater than 85% suppression for florfenicol amine to 70% matrix enhancement for chloramphenicol 3-O-β-d-glucuronide. Quantitation and confirmation were accomplished using commercially available penta-deuterated chloramphenicol as internal standard and multiple reaction monitoring (MRM) of two or three transitions per target analyte. Method accuracy was greater than 15% for all compounds except the glucuronide metabolite. Intra-lab method repeatability estimates ranged from 73% RSD for chloramphenicol 3-O-β-d-glucuronide to 14% RSD for chloramphenicol. Only chloramphenicol 3-O-β-d-glucuronide and florfenicol amine at the low end of their calibration ranges (0.25 and 1ng/g, respectively) did not meet AOAC recommended HorRatr guidelines for intra-lab repeatabilities. Preliminary tests show that the method's extraction protocol can be used to recover analytes of the β-agonists, corticosteroids, fluoroquinolones, sulfonamides, and tetracycline drug classes from the same matrices. Requirements for use in national chemical monitoring programs as a detection/confirmatory (florfenicol amine and

  18. Regulatory regions that control expression of two chloramphenicol-inducible cat genes cloned in Bacillus subtilis.

    PubMed

    Duvall, E J; Williams, D M; Mongkolsuk, S; Lovett, P S

    1984-06-01

    Plasmid pPL603 is a promoter cloning vector for Bacillus subtilis and consists of a 1.1-kilobase fragment of Bacillus pumilus DNA inserted between the EcoRI and BamHI sites of pUB110. The gene cat-86, specifying chloramphenicol-inducible chloramphenicol acetyltransferase, is located on the 1.1-kilobase cloned DNA. When pPL603 is present in B. subtilis, cat-86 is unexpressed during vegetative growth but expressed during sporulation. The regulation of cat-86 in pPL603 is due to sequences within two restriction fragments, designated P1 and R1, that precede the main coding portion of the gene. The P1 fragment promotes transcription of cat-86 only during sporulation, whereas the adjacent R1 fragment lacks promoter function but contains sequences essential to chloramphenicol inducibility. A second B. pumilus gene, cat-66, was cloned in B. subtilis and is expressed throughout the vegetative growth and sporulation cycle. The cat-66 coding region is preceded by two adjacent restriction fragments designated as P2 and R2. P1 and P2 are identical in size and share 95% conservation of base sequence. R1 and R2 are also identical in size and share 91% conservation of base sequence. Fragment substitution experiments demonstrate that R2 can functionally replace R1. The substitution of P2 for P1 promotes cat-86 expression throughout vegetative growth and sporulation. Analysis of a derivative of pPL603 in which P2 has replaced P1 demonstrates that P2 promotes transcription of cat-86 during vegetative growth and that P2 contains the start site for transcription of cat-86. Thus, P1 and P2 differ strikingly in vegetative promoter function, yet they differ by single-base substitutions at only 11 positions of 203.

  19. Expression of a streptomycete leaderless mRNA encoding chloramphenicol acetyltransferase in Escherichia coli.

    PubMed Central

    Wu, C J; Janssen, G R

    1997-01-01

    The chloramphenicol acetyltransferase (cat) gene from Streptomyces acrimycini encodes a leaderless mRNA. Expression of the cat coding sequence as a leaderless mRNA from a modified lac promoter resulted in chloramphenicol resistance in Escherichia coli. Transcript mapping with nuclease S1 confirmed that the 5' end of the cat message initiated at the A of the AUG translational start codon. Site-directed mutagenesis of the lac promoter or the cat start codon abolished chloramphenicol resistance, indicating that E. coli initiated translation at the 5' terminal AUG of the cat leaderless mRNA. Addition of 5'-AUGC-3' to the 5' end of the cat mRNA resulted in translation occurring also from the reading frame defined by the added AUG triplet, suggesting that a 5'-terminal start codon is an important recognition feature for initiation and establishing reading frame during translation of leaderless mRNA. Addition of an untranslated leader and Shine-Dalgarno sequence to the cat coding sequence increased cat expression in a cat:lacZ fusion; however, the level of expression was significantly lower than when a fragment of the bacteriophage lambda cI gene, also encoding a leaderless mRNA, was fused to lacZ. These results indicate that in the absence of an untranslated leader and Shine-Dalgarno sequence, the streptomycete cat mRNA is translated by E. coli; however, the cat translation signals, or other features of the cat mRNA, provide for only a low level of expression in E. coli. PMID:9352935

  20. Evidence of natural occurrence of the banned antibiotic chloramphenicol in herbs and grass

    PubMed Central

    Berendsen, Bjorn; de Jong, Jacob; Nielen, Michel; Tserendorj, Enkhtuya; Sodnomdarjaa, Ruuragchas; Cannavan, Andrew; Elliott, Christopher

    2010-01-01

    Chloramphenicol (CAP), a broad-spectrum antibiotic, was detected in several herb and grass samples from different geographic origins. Due to its suspected carcinogenicity and linkages with the development of aplastic anemia in humans, CAP is banned for use in food-producing animals in the European Union (EU) and many other countries. However, products of animal origin originating from Asian countries entering the European market are still found noncompliant (containing CAP) on a regular basis, even when there is no history of chloramphenicol use in these countries. A possible explanation for the continued detection of these residues is the natural occurrence of CAP in plant material which is used as animal feed, with the consequent transfer of the substance to the animal tissues. Approximately 110 samples were analyzed using liquid chromatography coupled with mass spectrometric detection. In 26 samples, the presence of CAP was confirmed using the criteria for banned substances defined by the EU. Among other plant materials, samples of the Artemisia family retrieved from Mongolia and from Utah, USA, and a therapeutic herb mixture obtained from local stores in the Netherlands proved to contain CAP at levels ranging from 0.1 to 450 µg/kg. These findings may have a major impact in relation to international trade and safety to the consumer. The results of this study demonstrate that noncompliant findings in animal-derived food products may in part be due to the natural occurrence of chloramphenicol in plant material. This has implications for the application of current EU, USA, and other legislation and the interpretation of analytical results with respect to the consideration of CAP as a xenobiotic veterinary drug residue and the regulatory actions taken upon its detection in food. PMID:20431869

  1. Evidence of natural occurrence of the banned antibiotic chloramphenicol in herbs and grass.

    PubMed

    Berendsen, Bjorn; Stolker, Linda; de Jong, Jacob; Nielen, Michel; Tserendorj, Enkhtuya; Sodnomdarjaa, Ruuragchas; Cannavan, Andrew; Elliott, Christopher

    2010-07-01

    Chloramphenicol (CAP), a broad-spectrum antibiotic, was detected in several herb and grass samples from different geographic origins. Due to its suspected carcinogenicity and linkages with the development of aplastic anemia in humans, CAP is banned for use in food-producing animals in the European Union (EU) and many other countries. However, products of animal origin originating from Asian countries entering the European market are still found noncompliant (containing CAP) on a regular basis, even when there is no history of chloramphenicol use in these countries. A possible explanation for the continued detection of these residues is the natural occurrence of CAP in plant material which is used as animal feed, with the consequent transfer of the substance to the animal tissues. Approximately 110 samples were analyzed using liquid chromatography coupled with mass spectrometric detection. In 26 samples, the presence of CAP was confirmed using the criteria for banned substances defined by the EU. Among other plant materials, samples of the Artemisia family retrieved from Mongolia and from Utah, USA, and a therapeutic herb mixture obtained from local stores in the Netherlands proved to contain CAP at levels ranging from 0.1 to 450 microg/kg. These findings may have a major impact in relation to international trade and safety to the consumer. The results of this study demonstrate that noncompliant findings in animal-derived food products may in part be due to the natural occurrence of chloramphenicol in plant material. This has implications for the application of current EU, USA, and other legislation and the interpretation of analytical results with respect to the consideration of CAP as a xenobiotic veterinary drug residue and the regulatory actions taken upon its detection in food.

  2. Stability of sulfonamides, nitrofurans, and chloramphenicol residues in preserved raw milk samples measured by liquid chromatography.

    PubMed

    Noa, Mario; Perez, Norima; Gutierrez, Rey; Escobar, Irma; Diaz, Gilberto; Vega, Salvador; Prado, Guadalupe; Urban, Georgina

    2002-01-01

    A stability study was made of 10 antimicrobials: 6 sulfonamides, 3 nitrofurans, and chloramphenicol residues in raw milk samples preserved with 0.1 % potassium dichromate (K2Cr2O7) and 0.05% mercuric bichloride (HgCl2) during cold storage for 7 days. Preserved milk samples fortified with 50 ppb of each antimicrobial were analyzed by liquid chromatography (modified AOAC Method 993.32). Drugs were extracted with chloroform-acetone after solvent evaporation residues were dissolved with aqueous sodium acetate buffer solution (0.02M, pH 4.8), and fat was removed with hexane. Sulfonamides and chloramphenicol were detected at 275 nm (UV) by using a gradient system of sodium acetate buffer solution-acetonitrile starting at 95 + 5 (v/v) and finishing at 80 + 20 (v/v). Nitrofurans were detected at 375 nm (UV) isocratically with sodium acetate buffer solution-acetonitrile (80 + 20, v/v). Residues stability was measured through recovery data. Sulfamethoxazole, sulfachloropyridazine, nitrofurazone, furazolidone, and furaltadone residues remained stable in the presence of either preservative for 7 days. Sulfamethazine and chloramphenicol were not affected by K2Cr2O7, but had significant losses (p <0.05) when HgCl2 was used: 26.2 and 13.4%, respectively. Average recoveries of sulfamonomethoxine, sulfamerazine, and sulfathiazole significantly decreased by Day 7, with losses of 17.1, 17.2, and 23.2% for K2Cr2O7, and 23.3, 20.7, and 48.0% for HgCl2, respectively. During 5 days of cold storage all antimicrobials tested, except sulfathiazole, remained stable in milk samples preserved with 0.1 % K2Cr2O7 or 0.05% HgCl2.

  3. Specification of the immune response: its suppression induced by chloramphenicol in vitro.

    PubMed

    Couderc, J; Perrodon, Y; Ventura, M; Liacopoulos, P; Danchin, A

    1983-01-01

    Specific in vitro PFC responses to trinitrophenyl conjugated to sheep red blood cells are inhibited by chloramphenicol (CAP), thiamphenicol (TAP), and diuron (DIU) by B-cell impairment. However, both mitogenic and polyclonal response to lipopolysaccharide is not affected by CAP and TAP but severely inhibited by DIU. Similarly, contact of cultured cells for the first 24 h with CAP did not much affect the 4th-day in vitro PFC response but the same incubation with DIU reduced it by 70%. Moreover, DIU used at the same concentration provoked an important mortality of cultured cells. These differences suggest that the target mechanism of CAP and TAP differs from that of DIU.

  4. Rapid determination of chloramphenicol residues in aquaculture tissues by immunochromatographic assay.

    PubMed

    Li, Ke; Liu, Liqiang; Xu, ChuanLai; Chu, XiaoGang

    2007-11-01

    An immunochromatographic assay was developed to detect chloramphenicol (CAP) residues in aquaculture tissues. The limit of detection (LOD) was 10 ng g(-1) for detecting CAP spiked in the aquaculture tissues. The results were confirmed by liquid chromatography tandem mass spectrometry (LC/MS/MS) and indicated that there was a good agreement between the two methods. The linear regression equation was y = 1.19x + 0.539 with R(2) = 0.978. The assay time for test was less than 5 min and the method is suitable for rapid testing on-site.

  5. Quantum dot-based lateral flow immunoassay for detection of chloramphenicol in milk.

    PubMed

    Berlina, Anna N; Taranova, Nadezhda A; Zherdev, Anatoly V; Vengerov, Yuri Y; Dzantiev, Boris B

    2013-05-01

    A novel rapid (20 min) fluorescent lateral flow test for chloramphenicol (CAP) detection in milk was developed. The chosen format is a binding-inhibition assay. Water-soluble quantum dots with an emission peak at 625 nm were applied as a label. Milk samples were diluted by 20 % with phosphate buffer to eliminate the matrix effect. The result of the assay could be seen by eye under UV light excitation or registered by a portable power-dependent photometer. The limit of CAP detection by the second approach is 0.2 ng/mL, and the limit of quantitation is 0.3 ng/mL.

  6. Persistence of Salmonellae in Blood and Bone Marrow: Randomized Controlled Trial Comparing Ciprofloxacin and Chloramphenicol Treatments against Enteric Fever

    PubMed Central

    Gasem, M. Hussein; Keuter, Monique; Dolmans, Wil M. V.; van der Ven-Jongekrijg, Johanna; Djokomoeljanto, Robert; van der Meer, Jos W. M.

    2003-01-01

    We performed a randomized controlled trial involving 55 adult patients with enteric fever to compare ciprofloxacin and chloramphenicol. Blood and bone marrow cultures and cytokine profiles during therapy were done to compare the clinical and bacteriological efficacies of these drugs. All patients were randomly assigned to receive chloramphenicol (500 mg four times a day orally) for 14 days or ciprofloxacin (500 mg twice a day orally) for 7 days. In each treatment group, patients were subsequently randomized to have blood and bone marrow cultured after either 3 or 5 days of treatment. Twenty-seven patients received chloramphenicol, and 28 received ciprofloxacin. The two groups were similar in terms of baseline characteristics. No significant differences in clinical cure and time to defervescence were found. All strains isolated were susceptible to both antibiotics. Although ciprofloxacin was more effective in the elimination of Salmonella enterica serovars Typhi and Paratyphi A from bone marrow than chloramphenicol, there was still an impressive persistence of Salmonella in the bone marrow culture (67%). In the ciprofloxacin-treated patients the suppressed cytokine production capacity showed a trend to normalize earlier than in patients treated with chloramphenicol. PMID:12709347

  7. Identification of the chloramphenicol-hydrolyzing enzyme of guinea pig liver as one of the nonspecific carboxylesterases.

    PubMed

    Kuhn, D; Heymann, E

    1982-03-01

    Guinea pig liver has the highest chloramphenicol-hydrolyzing capacity among the livers of various mammals. The enzyme responsible for the hydrolysis of the amide-bond in chloramphenicol is one of the isoenzymes of the microsomal nonspecific carboxylesterases. This isoenzyme is related to the well-known acetanilide-hydrolyzing carboxylesterases/amidases of pig and rat liver. The guinea pig liver enzyme is purified 24-fold starting with microsomes. The purified enzyme is essentially free from other proteins except other carboxylesterase isoenzymes with similar properties. The chloramphenicol-hydrolyzing esterase has an apparent molecular weight of about 180,000, a subunit weight of 60,000 and a pH optimum at 8.5. It also hydrolyzes methyl butyrate and acetanilide and it is completely inhibited by diethyl-4-nitrophenyl phosphate. Two assay procedures for the enzymatic chloramphenicol hydrolysis are described: a thin-layer chromatographic assay using radioactive chloramphenicol and a colorimetric assay utilizing the reaction of the liberated amine with trinitrobenzenesulfonic acid.

  8. High resolution studies of the Afa/Dr adhesin DraE and its interaction with chloramphenicol.

    PubMed

    Pettigrew, David; Anderson, Kirstine L; Billington, Jason; Cota, Ernesto; Simpson, Peter; Urvil, Petri; Rabuzin, Filip; Roversi, Pietro; Nowicki, Bogdan; du Merle, Laurence; Le Bouguénec, Chantal; Matthews, Stephen; Lea, Susan M

    2004-11-05

    Pathogenic Escherichia coli expressing Afa/Dr adhesins are able to cause both urinary tract and diarrheal infections. The Afa/Dr adhesins confer adherence to epithelial cells via interactions with the human complement regulating protein, decay accelerating factor (DAF or CD55). Two of the Afa/Dr adhesions, AfaE-III and DraE, differ from each other by only three residues but are reported to have several different properties. One such difference is disruption of the interaction between DraE and CD55 by chloramphenicol, whereas binding of AfaE-III to CD55 is unaffected. Here we present a crystal structure of a strand-swapped trimer of wild type DraE. We also present a crystal structure of this trimer in complex with chloramphenicol, as well as NMR data supporting the binding position of chloramphenicol within the crystal. The crystal structure reveals the precise atomic basis for the sensitivity of DraE-CD55 binding to chloramphenicol and demonstrates that in contrast to other chloramphenicol-protein complexes, drug binding is mediated via recognition of the chlorine "tail" rather than via intercalation of the benzene rings into a hydrophobic pocket.

  9. 4-alkoxy and 4-thioalkoxyquinoline derivatives as chemosensitizers for the chloramphenicol-resistant clinical Enterobacter aerogenes 27 strain.

    PubMed

    Gallo, Sandrine; Chevalier, Jacqueline; Mahamoud, Abdallah; Eyraud, Annie; Pagès, Jean-Marie; Barbe, Jacques

    2003-09-01

    Enterobacter aerogenes is a Gram-negative bacteria frequently responsible for nosocomial respiratory tract infections. Strains resistant to chloramphenicol are frequently isolated. Alkoxy and thio-alkoxyquinolines have a potential to act as chemosensitizers that would render multi-drug-resistant (MDR) bacterial infections susceptible to antibiotics to which they were originally resistant. Several new quinoline derivatives have been prepared, characterized and studied for their ability to increase chloramphenicol sensitivity of E. aerogenes 27, a clinical strain that exhibits the MDR phenotype. Drugs investigated were either quinoline ethers or quinoline thio-ethers. Thio-ethers are much more efficient in increasing chloramphenicol sensitivity than other corresponding ethers. In particular, 4-piperidinoethylthio-quinoline increases the strain sensitivity to chloramphenicol by about 20 times at 2 mM concentration. Similarly, sensitivity to quinolone antibiotics dramatically increases. Because these quinoline derivatives act as inhibitors of the drug efflux pump responsible for bacterial resistance to chloramphenicol, they may serve as adjunct to conventional therapy of E. aerogenes infections.

  10. Preparation of Chloramphenicol/Amino Acid Combinations Exhibiting Enhanced Dissolution Rates and Reduced Drug-Induced Oxidative Stress.

    PubMed

    Sterren, Vanesa B; Aiassa, Virginia; Garnero, Claudia; Linck, Yamila Garro; Chattah, Ana K; Monti, Gustavo A; Longhi, Marcela R; Zoppi, Ariana

    2017-04-20

    Chloramphenicol is an old antibiotic agent that is re-emerging as a valuable alternative for the treatment of multidrug-resistant pathogens. However, it exhibits suboptimal biopharmaceutical properties and toxicity profiles. In this work, chloramphenicol was combined with essential amino acids (arginine, cysteine, glycine, and leucine) with the aim of improving its dissolution rate and reduce its toxicity towards leukocytes. The chloramphenicol/amino acid solid samples were prepared by freeze-drying method and characterized in the solid state by using Fourier transform infrared spectroscopy, powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and solid-state nuclear magnetic resonance. The dissolution properties, antimicrobial activity, reactive oxygen species production, and stability of the different samples were studied. The dissolution rate of all combinations was significantly increased in comparison to that of the pure active pharmaceutical ingredient. Additionally, oxidative stress production in human leukocytes caused by chloramphenicol was decreased in the chloramphenicol/amino acid combinations, while the antimicrobial activity of the antibiotic was maintained. The CAP:Leu binary combination resulted in the most outstanding solid system makes it suitable candidate for the development of pharmaceutical formulations of this antimicrobial agent with an improved safety profile.

  11. Physico-chemical factors affect chloramphenicol efflux and EmhABC efflux pump expression in Pseudomonas fluorescens cLP6a.

    PubMed

    Adebusuyi, Abigail; Foght, Julia

    2013-01-01

    Protein synthesis inhibitors such as chloramphenicol and tetracycline may be inducers of efflux pumps such as MexY in Pseudomonas aeruginosa, complicating their use for the treatment of bacterial infections. We previously determined that chloramphenicol, a substrate of the EmhABC efflux pump in Pseudomonas fluorescens cLP6a, did not induce emhABC expression. In this study, we determined the effect of physico-chemical factors on chloramphenicol efflux by EmhABC, and the expression of emhABC. Efflux assays measuring accumulation of (14)C-chloramphenicol in cell pellets showed that chloramphenicol efflux is dependent on growth temperature, pH and concentration of Mg(2+). These physico-chemical factors modulated the efflux of chloramphenicol by 26 to >50%. All conditions tested that decreased the efflux of chloramphenicol unexpectedly induced transcription of emhABC efflux genes. EmhABC activity also effectively suppressed the deleterious effect of chloramphenicol on the cell membrane of strain cLP6a, which may explain why chloramphenicol is not an inducer of emhABC. Our results suggest that the detrimental effect of an antibiotic on cell membrane integrity and fatty acid composition may be the signal that induces emhABC expression, and that inducers of other bacterial efflux pumps may include environmental factors rather than their substrates per se.

  12. Determination of nitrofuran and chloramphenicol residues by high resolution mass spectrometry versus tandem quadrupole mass spectrometry.

    PubMed

    Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

    2015-03-03

    An ultra-high performance liquid chromatography based method, coupled to high resolution mass spectrometry (UHPLC-HRMS), was developed to permit the detection and quantification of various nitrofuran and chloramphenicol residues in a number of animal based food products. This method is based on the hydrolysis of covalently bound metabolites and derivatization with 2-nitrobenzaldehyde. Clean-up is achieved by a liquid/liquid and a reversed phase/solid phase extraction. Not only are the four conventional nitrofurans (nitrofurantoin, furazolidone, nitrofurazone and furaltadone) detected, but also nifursol, nitrovin and nifuroxazide. Furthermore, an underivatizable nitrofuran (nifurpirinol) and another banned drug (chloramphenicol) can be quantified as well. The compounds are detected in the form of their precursor ions, [M+H](+) and [M-H](-), respectively. The mass resolving power of 70,000 FWHM, and the applied mass window ensure sufficient selectivity and sensitivity. Confirmation is obtained by monitoring the HRMS resolved product ions which were derived from the unit-mass resolved precursor ions. The multiplexing capability of the utilized Orbitrap instrument provides not only highly selective, but also sensitive confirmatory signals. This method has been validated according to the CD 2002/657/EC for the following matrices: muscle, liver, kidney, fish, honey, eggs and milk.

  13. Total determination of chloramphenicol residues in foods by liquid chromatography-tandem mass spectrometry.

    PubMed

    Kikuchi, Hiroyuki; Sakai, Takatoshi; Teshima, Reiko; Nemoto, Satoru; Akiyama, Hiroshi

    2017-09-01

    A simple and sensitive analytical method for the determination of chloramphenicol (CAP) and chloramphenicol glucuronide (CAPG) residues in foods such as livestock products, seafood, honey and royal jelly was developed. The method comprises solvent extraction with methanol, enzymatic hydrolysis with β-glucuronidase and clean-up using a hydrophilic lipophilic balanced copolymer solid phase extraction column. To determine the optimal conditions for the complete enzymatic hydrolysis of CAPG, we examined the effect of enzyme concentration and incubation time on the hydrolysis. The detection of CAP using LC-MS/MS was optimized and determined by SRM. The developed method was validated using ten food products at a spiked level of 0.5μg/kg. The validation results show excellent recoveries (79-109%) and precision (<15%) for CAP and CAPG. The limit of quantification (S/N≥10) of the developed method was 0.5μg/kg. The proposed method would be useful for the regulatory monitoring of CAP and CAPG residues in foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Chloramphenicol with fluid and electrolyte therapy cures terminally ill green tree frogs (Litoria caerulea) with chytridiomycosis.

    PubMed

    Young, Sam; Speare, Rick; Berger, Lee; Skerratt, Lee F

    2012-06-01

    Terminal changes in frogs infected with the amphibian fungal pathogen Batrachochytrium dendrobatidis (Bd) include epidermal degeneration leading to inhibited epidermal electrolyte transport, systemic electrolyte disturbances, and asystolic cardiac arrest. There are few reports of successful treatment of chytridiomycosis and none that include curing amphibians with severe disease. Three terminally ill green tree frogs (Litoria caerulea) with heavy Bd infections were cured using a combination of continuous shallow immersion in 20 mg/L chloramphenicol solution for 14 days, parenteral isotonic electrolyte fluid therapy for 6 days, and increased ambient temperature to 28 degrees C for 14 days. All terminally ill frogs recovered rapidly to normal activity levels and appetite within 5 days of commencing treatment. In contrast, five untreated terminally ill L. caerulea with heavy Bd infections died within 24-48 hr of becoming moribund. Subclinical infections in 15 experimentally infected L. caerulea were cured within 28 days by continuous shallow immersion in 20 mg/L chloramphenicol solution without adverse effects. This is the first known report of a clinical treatment protocol for curing terminally ill Bd-infected frogs.

  15. Pharmacokinetics of amikacin and chloramphenicol in the aqueous humor of rabbits.

    PubMed Central

    Mayers, M; Rush, D; Madu, A; Motyl, M; Miller, M H

    1991-01-01

    Composite data describing ocular pharmacokinetics are unreliable because of intersubject variation. To address this problem, an animal model was developed in which multiple aqueous samples from single subjects were obtained. Following direct anterior chamber or intravenous administration of amikacin or chloramphenicol, pharmacokinetic analysis of drug concentrations in the serum and anterior chamber was performed by using a nonlinear least-squares regression program. The number of anterior chamber paracenteses performed did not alter the beta elimination rates or percent penetration into the anterior chamber. The aqueous humor and peripheral-compartment terminal slopes were identical. These data indicate that complete ocular concentration-time curves can be obtained without altering antibiotic pharmacokinetics. Following direct injection into the anterior chamber, the elimination rates for both antibiotics followed a one-compartment model, whereas those following intravenous administration best fit an open, first-order, two-compartment model. Following intravenous administration, the anterior chamber elimination rate constants for both drugs were equal to that of the serum and significantly longer than that following direct injection. The elimination rates of both drugs following direct injection were similar. Systemic administration resulted in drug levels in aqueous humor that persisted longer than those following direct injection. Chloramphenicol, a lipophilic compound, gave higher mean concentrations in aqueous humor than did amikacin. Our model provides a new approach which rigorously examines ocular pharmacokinetics and provides data which suggest that for selected compounds the parenteral route of administration is preferable. PMID:1952850

  16. Influence of tonicity and chloramphenicol on hyperthermic cytotoxicity and cell permeability under various heating rates.

    PubMed

    Morozov, I I; Petin, V G; Dubovick, B V

    1997-01-01

    The cell lethality and permeability induced in Escherichia coli B/r, Escherichia coli Bs-1 and Zygosaccharomyces bailii cells by high temperature (52 degrees C) after heating at different rates (mean s 0.015, 0.25 and 1.50 degrees C per s) and in media of different tonicity and content (isotonic YEP broth versus 0.01 M phosphate buffer, pH 7.0 containing different concentrations of NaCl) and with versus without chloramphenicol (10 micrograms/ml) have been investigated. Hyperthermic treatment in YEP broth of isotonic 0.01 M phosphate buffer resulted in markedly reduced cytotoxicity with decreasing heat rate. The heating rate effect was larger when the cells were treated in YEP broth. Chloramphenicol, which is known to inhibit expression of heat shock proteins in bacteria, did not affect the viability of cells or the development of thermotolerance in cells heated at different heating rates in isotonic phosphate buffer but prevented the development of an additional degree of thermotolerance in cells heated slowly in YEP broth. In contrast, the differential effect of heating rate on cytotoxicity and cell permeability was not demonstrated when cells were heated in hypertonic solution (1M NaCl in phosphate buffer, pH 7.0). It is proposed that heat destabilization of the osmotic cell homeostasis, which is more profound after rapid heating, plays a major part in heat induced cellular lethality.

  17. Chloramphenicol succinate, a competitive substrate and inhibitor of succinate dehydrogenase: possible reason for its toxicity.

    PubMed

    Ambekar, C S; Lee, J S K; Cheung, B M Y; Chan, L C; Liang, R; Kumana, C R

    2004-08-01

    From our previous study [Eur. J. Clin. Pharmacol. 56 (2000) 405] we hypothesized that chloramphenicol succinate (CAPS) may be a competitive substrate for succinate dehydrogenase (SDH). It may be oxidized by SDH to release chloramphenicol (CAP), which may inhibit SDH by feed back mechanism. The present ex-vivo/in vitro study was aimed to investigate this possibility by using human tissues (bone marrow and liver samples) and animal tissues (rat liver and kidney). The effect of different SDH activators and specific inhibitors was studied on CAPS metabolism by SDH. The metabolites and reduction products were detected by using HPLC. In marrow samples, CAPS was slowly oxidized to form CAP. The formation of CAP (oxidation product) was enhanced by FAD and low malonate and inhibited by high malonate and 3-NPA. Similar results were obtained with mitochondria from human and rat tissues. These studies suggest that CAPS could be a competitive oxidative substrate and the metabolite CAP could be an inhibitor at the reduction site. Therefore, SDH could be a target molecule responsible for CAPS induced toxicity.

  18. Synthesis and Evaluation of Chloramphenicol Homodimers: Molecular Target, Antimicrobial Activity, and Toxicity against Human Cells

    PubMed Central

    Kostopoulou, Ourania N.; Magoulas, George E.; Papadopoulos, Georgios E.; Mouzaki, Athanasia; Dinos, George P.; Papaioannou, Dionissios; Kalpaxis, Dimitrios L.

    2015-01-01

    As fight against antibiotic resistance must be strengthened, improving old drugs that have fallen in reduced clinical use because of toxic side effects and/or frequently reported resistance, like chloramphenicol (CAM), is of special interest. Chloramphenicol (CAM), a prototypical wide-spectrum antibiotic has been shown to obstruct protein synthesis via binding to the bacterial ribosome. In this study we sought to identify features intensifying the bacteriostatic action of CAM. Accordingly, we synthesized a series of CAM-dimers with various linker lengths and functionalities and compared their efficiency in inhibiting peptide-bond formation in an Escherichia coli cell-free system. Several CAM-dimers exhibited higher activity, when compared to CAM. The most potent of them, compound 5, containing two CAM bases conjugated via a dicarboxyl aromatic linker of six successive carbon-bonds, was found to simultaneously bind both the ribosomal catalytic center and the exit-tunnel, thus revealing a second, kinetically cryptic binding site for CAM. Compared to CAM, compound 5 exhibited comparable antibacterial activity against MRSA or wild-type strains of Staphylococcus aureus, Enterococcus faecium and E. coli, but intriguingly superior activity against some CAM-resistant E. coli and Pseudomonas aeruginosa strains. Furthermore, it was almost twice as active in inhibiting the growth of T-leukemic cells, without affecting the viability of normal human lymphocytes. The observed effects were rationalized by footprinting tests, crosslinking analysis, and MD-simulations. PMID:26267355

  19. Pyrite-enhanced degradation of chloramphenicol by low concentrations of H2O2.

    PubMed

    Wu, Deli; Liu, Yanxia; Zhang, Zhiyong; Ma, Luming; Zhang, Yalei

    2015-01-01

    A pyrite-catalyzed reaction was used to degrade chloramphenicol. Chloramphenicol could be almost 100% removed within 60 minutes when 1 mM H2O2 and 0.1 g/L pyrite were added at an initial pH=3. During oxidation, intermediates such as nitrobenzaldehyde and dichloroacetamide were identified by gas chromatography/mass spectrometry (GC/MS). The •OH was identified by electron spin-resonance spectroscopy. Pyrite was digested to determine elements by ICP (inductive coupled plasma emission spectrometer). To understand the reaction mechanism and the role of natural pyrite in these processes, techniques including scanning electron microscopy and energy dispersive spectrometry were employed to characterize the solid sample. The results explain that pyrite acts as a 'bond' between Fe3+ and H2O2, and this pathway continues to form •OH and inhibit the quenching reaction. Therefore, pyrite-catalyzed reactions would proceed even in low concentrations of H2O2.

  20. Saccharothrix sp. PAL54, a new chloramphenicol-producing strain isolated from a Saharan soil.

    PubMed

    Aouiche, Adel; Sabaou, Nasserdine; Meklat, Atika; Zitouni, Abdelghani; Bijani, Christian; Mathieu, Florence; Lebrihi, Ahmed

    2012-03-01

    An actinomycete strain designated PAL54, producing an antibacterial substance, was isolated from a Saharan soil in Ghardaïa, Algeria. Morphological and chemical studies indicated that this strain belonged to the genus Saccharothrix. Analysis of the 16S rDNA sequence showed a similarity level ranging between 96.9 and 99.2% within Saccharothrix species, with S. longispora DSM 43749(T), the most closely related. DNA-DNA hybridization confirmed that strain PAL54 belonged to Saccharothrix longispora. It showed very strong activity against pathogenic Gram-positive and Gram-negative bacteria responsible for nosocomial infections and resistant to multiple antibiotics. Strain PAL54 secreted the antibiotic optimally during mid-stationary and decline phases of growth. One antibacterial compound was isolated from the culture broth and purified by HPLC. The active compound was elucidated by uv-visible and NMR spectroscopy and by mass spectrometry. The results showed that this compound was a D: (-)-threo chloramphenicol. This is the first report of chloramphenicol production by a Saccharothrix species.

  1. Azithromycin, fluoroquinolone and chloramphenicol resistance of non-chlamydia conjunctival bacteria in rural community of Ethiopia

    PubMed Central

    Abera, Bayeh; Kibret, Mulugeta

    2014-01-01

    Aim: To determine profiles of non-chlamydia conjunctival bacteria and their antimicrobial susceptibility from adults who underwent trachomatous trichiasis surgery in rural areas of Ethiopia. Materials and Methods: A cross-sectional study was conducted in rural districts in West Gojjam administrative zone. Conjunctival swabs were collected during surgery and transported using Stuart transport broth (Oxoid, UK). Antibiotic susceptibility of conjunctival isolates was determined using the Kirby-Bauer disc-diffusion method. Results: Non-chlamydia pathogenic bacteria were recovered from conjunctiva of 438 (31%) participants before treatment. The isolated conjunctival bacteria were Staphylococcus aureus, coagulase-negative Staphylococci, Streptococcus group (A, C, F and G), Enterococci, Streptococcus pneumoniae, Moraxella spp., Escherichia coli, Citrobacter spp., Proteus spp., Klebsiella spp., Pseudomonas spp. and Enterobacter spp. Overall, resistance rates of 57.8% to azithromycin and 68.5% to chloramphenicol were found. However, 86-94.4% sensitivity was demonstrated to ciprofloxacin and norfloxacin. Moderate sensitivity rates (61.8-78.4%) were observed to ceftriaxone, tetracycline and cotrimoxazole. Conclusion: Fluoroquinolones that have activity against the majority of bacterial isolates were potent at in vitro. However, unacceptably high levels of resistance to azithromycin and chloramphenicol in rural community indicated a need for further study and antimicrobial resistance surveillance. PMID:23571246

  2. An amperometric chloramphenicol immunosensor based on cadmium sulfide nanoparticles modified-dendrimer bonded conducting polymer.

    PubMed

    Kim, Dong-Min; Rahman, Md Aminur; Do, Minh Hien; Ban, Changill; Shim, Yoon-Bo

    2010-03-15

    An amperometric chloramphenicol (CAP) immunosensor was fabricated by covalently immobilizing anti-chloramphenicol acetyl transferase (anti-CAT) antibody on cadmium sulfide nanoparticles (CdS) modified-dendrimer that was bonded to the conducting polymer (poly 5, 2': 5', 2''-terthiophene-3'-carboxyl acid (poly-TTCA)) layer. The AuNPs, dendrimers, and CdS nanoparticles were deposited onto the polymer layer in order to enhance the sensitivity of the sensor probes. The particle sizes were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The immobilization of dendrimers, CdS, and anti-CAT were confirmed using energy disruptive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance (QCM) techniques. The detection of CAP was based on the competitive immuno-interaction between the free- and labeled-CAP for active sites of the anti-CAT. Hydrazine was used as the label for CAP, and it electrochemically catalyzed the reduction of H(2)O(2) at -0.35 V vs. Ag/AgCl. Under optimized conditions, the proposed immunosensor exhibited a linear range of CAP detection between 50 pg/mL and 950 pg/mL, and the detection limit was 45 pg/mL. The immunosensor was examined in real meat samples for the analysis of CAP.

  3. Final report on key comparison CCQM-K81: Chloramphenicol in pig muscle

    NASA Astrophysics Data System (ADS)

    Polzer, Joachim; Henrion, Andre; Gowik, Petra

    2013-01-01

    Under the auspices of the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a key comparison, CCQM-K81 'Chloramphenicol in pig muscle', was coordinated by BVL and PTB in 2009/2010. Six NMIs/DIs participated in this comparison. Chloramphenicol (CAP) is an effective broad-spectrum antibiotic which can in principle be used for the treatment of humans and animals. Its use for the treatment of food-producing animals is, however, forbidden worldwide in many countries due to potential severe side effects. The key comparison was the follow-up to the successful pilot study 'CCQM-P90: chloramphenicol in milk'. With this key comparison it was intended to demonstrate the capability of NMIs/DIs to analyse traces of CAP in food at concentration levels resulting from legal requirements for food control. Additionally, the quality of this kind of analysis with respect to compliance with legal requirements for food control methods and the international comparability of measurements should be evaluated in general. The study was classified as a 'track C' study (studies in emerging areas of global interest). For the study incurred lyophilised pig muscle material containing CAP (at a mass-fraction level around the maximum allowable level for import for a number of countries) has been produced as a candidate reference material by BVL and IRMM (Institute for Reference Materials and Measurements, JRC of the European Commission). Animal treatment and slaughtering of the animal to gain incurred muscle material as well as pre-testing of the CAP content was done at the BVL. The IRMM did further processing of the material and testing of homogeneity and stability. Participants were invited to assign the mass fraction of free CAP in the comparison sample. CCQM-K81 demonstrated successfully the capability of the participating laboratories to assign chloramphenicol values in tissue down to residue levels of around 0.3 ng/g (referring to the

  4. Characterization and Uncertainty Assessment of a Certified Reference Material of Chloramphenicol in Methanol (GBW(E)082557)

    PubMed Central

    Zhou, Jian; Song, Yinqing; Wang, Tongtong

    2016-01-01

    Prior to preparation of CRM candidate of chloramphenicol in methanol with a concentration of 100 mg/L, two independent methods including mass balance (MB) and quantitative nuclear magnetic resonance (qNMR) were employed to precisely measure the mass fraction of pure chloramphenicol materials. The mass fraction was assigned to be 99.8% with uncertainty of 0.3%. Homogeneity testing and stability study of chloramphenicol in methanol were examined by using high performance liquid chromatography. Additionally, the uncertainties originating from the process of CRM development were comprehensively evaluated. The experimental results indicate that the property value of this CRM is homogeneous and stable at 4°C for at least six months. The new CRM (GBW(E)082557) can be applicable to calibration of instrument and assurance of accuracy and comparability of results in routine measurement. PMID:27493666

  5. Synergistic killing of NDM-producing MDR Klebsiella pneumoniae by two 'old' antibiotics-polymyxin B and chloramphenicol.

    PubMed

    Abdul Rahim, Nusaibah; Cheah, Soon-Ee; Johnson, Matthew D; Yu, Heidi; Sidjabat, Hanna E; Boyce, John; Butler, Mark S; Cooper, Matthew A; Fu, Jing; Paterson, David L; Nation, Roger L; Bergen, Phillip J; Velkov, Tony; Li, Jian

    2015-09-01

    Combination therapy is an important option in the fight against Gram-negative 'superbugs'. This study systematically investigated bacterial killing and the emergence of polymyxin resistance with polymyxin B and chloramphenicol combinations used against New Delhi metallo-β-lactamase (NDM)-producing MDR Klebsiella pneumoniae. Four NDM-producing K. pneumoniae strains were employed. The presence of genes conferring resistance to chloramphenicol was examined by PCR. Time-kill studies (inocula ∼10(6) cfu/mL) were conducted using various clinically achievable concentrations of each antibiotic (range: polymyxin B, 0.5-2 mg/L; chloramphenicol, 4-32 mg/L), with real-time population analysis profiles documented at baseline and 24 h. The microbiological response was examined using the log change method and pharmacodynamic modelling in conjunction with scanning electron microscopy (SEM). Multiple genes coding for efflux pumps involved in chloramphenicol resistance were present in all strains. Polymyxin B monotherapy at all concentrations produced rapid bacterial killing followed by rapid regrowth with the emergence of polymyxin resistance; chloramphenicol monotherapy was largely ineffective. Combination therapy significantly delayed regrowth, with synergy observed in 25 out of 28 cases at both 6 and 24 h; at 24 h, no viable bacterial cells were detected in 15 out of 28 cases with various combinations across all strains. No polymyxin-resistant bacteria were detected with combination therapy. These results were supported by pharmacodynamic modelling. SEM revealed significant morphological changes following treatment with polymyxin B both alone and in combination. The combination of polymyxin B and chloramphenicol used against NDM-producing MDR K. pneumoniae substantially enhanced bacterial killing and suppressed the emergence of polymyxin resistance. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All

  6. Nature of Col E1 Plasmid Replication in Escherichia coli in the Presence of Chloramphenicol

    PubMed Central

    Clewell, Don B.

    1972-01-01

    The colicinogenic factor E1 (Col E1) in Escherichia coli continues to replicate by a semiconservative mechanism in the presence of chloramphenicol (CAP) for 10 to 15 hr, long after chromosomal deoxyribonucleic acid (DNA) synthesis has terminated. Following CAP addition, the rate of synthesis of plasmid DNA gradually increases to an extent dependent on the medium employed. Within 2 to 4 hr after the addition of CAP, replication in a glucose-Casamino Acids medium approaches a maximum rate representing approximately eight times an average rate which would be required for a net doubling of DNA per cell in one generation. The number of copies of Col E1 DNA molecules that accumulate under these conditions approaches about 3,000 copies per cell, representing a 125-fold increase over the normal level of 24 copies per cell. The system is particularly convenient for studying the mechanism of DNA replication. Images PMID:4336693

  7. An improved electrochemical aptasensor for chloramphenicol detection based on aptamer incorporated gelatine.

    PubMed

    Hamidi-Asl, Ezat; Dardenne, Freddy; Blust, Ronny; De Wael, Karolien

    2015-03-27

    Because of the biocompatible properties of gelatine and the good affinity of aptamers for their targets, the combination of aptamer and gelatine type B is reported as promising for the development of biosensing devices. Here, an aptamer for chloramphenicol (CAP) is mixed with different types of gelatine and dropped on the surface of disposable gold screen printed electrodes. The signal of the CAP reduction is investigated using differential pulse voltammetry. The diagnostic performance of the sensor is described and a detection limit of 1.83 × 10(-10) M is found. The selectivity and the stability of the aptasensor are studied and compared to those of other CAP sensors described in literature.

  8. An electrochemical impedimetric aptasensing platform for sensitive and selective detection of small molecules such as chloramphenicol.

    PubMed

    Pilehvar, Sanaz; Dierckx, Tarryn; Blust, Ronny; Breugelmans, Tom; De Wael, Karolien

    2014-07-07

    We report on the aptadetection of chloramphenicol (CAP) using electrochemical impedance spectroscopy. The detection principle is based on the changes of the interfacial properties of the electrode after the interaction of the ssDNA aptamers with the target molecules. The electrode surface is partially blocked due to the formation of the aptamer-CAP complex, resulting in an increase of the interfacial electron-transfer resistance of the redox probe detected by electrochemical impedance spectroscopy or cyclic voltammetry. We observed that the ratio of polarization resistance had a linear relationship with the concentrations of CAP in the range of 1.76-127 nM, and a detection limit of 1.76 nM was obtained. The covalent binding of CAP-aptamer on the electrode surface combined with the unique properties of aptamers and impedimetric transduction leads to the development of a stable and sensitive electrochemical aptasensor for CAP.

  9. A highly sensitive europium nanoparticle-based lateral flow immunoassay for detection of chloramphenicol residue.

    PubMed

    Xia, Xiaohu; Xu, Ye; Ke, Rongqin; Zhang, Heng; Zou, Mingqiang; Yang, Wei; Li, Qingge

    2013-09-01

    A europium nanoparticle-based lateral flow immunoassay for highly sensitive detection of chloramphenicol residue was developed. The detection result could be either qualitatively resolved with naked eye or quantitatively analyzed with the assistance of a digital camera. In the qualitative mode, the limit of detection (LOD) was found to be 0.25 ng/mL. In the quantitative mode, the half-maximal inhibition concentration (IC50) was determined to be 0.45 ng/mL and the LOD can reach an ultralow level of 0.03 ng/mL, which is ~100 times lower than that of the conventional colloidal gold-based lateral flow immunoassay. Potential application of the established method was demonstrated by analyzing representative cow milk samples.

  10. Impact of Ciprofloxacin and Chloramphenicol on the Lipid Bilayer of Staphylococcus aureus: Changes in Membrane Potential

    PubMed Central

    Páez, Paulina L.; Becerra, María C.; Albesa, Inés

    2013-01-01

    The present study was undertaken to explore the interaction of ciprofloxacin and chloramphenicol with bacterial membranes in a sensitive and in a resistant strains of Staphylococcus aureus by using 1-anilino-8-naphthalene sulfonate (ANS). The binding of this probe to the cell membrane depends on the surface potential, which modulates the binding constant to the membrane. We observed that these antibiotics interacted with the bilayer, thus affecting the electrostatic surface potential. Alterations caused by antibiotics on the surface of the bacteria were accompanied by a reduction in the number of binding sites and an increase in the ANS dissociation constant in the sensitive strain, whereas in the ciprofloxacin-resistant strain no significant changes were detected. The changes seen in the electrostatic surface potential generated in the membrane of S. aureus by the antibiotics provide new aspects concerning their action on the bacterial cell. PMID:23762834

  11. PIXE investigation of in vitro release of chloramphenicol across polyvinyl alcohol/acrylamide hydrogel

    NASA Astrophysics Data System (ADS)

    Rihawy, M. S.; Alzier, A.; Allaf, A. W.

    2011-09-01

    Hydrogels based on polyvinyl alcohol and different amounts of acrylamide monomer were prepared by thermal cross-linking in the solid state. The hydrogels were investigated for drug delivery system applications. Chloramphenicol was adopted as a model drug to study its release behavior. Particle induced X-ray emission was utilized to study the drug release behavior across the hydrogels and a comparison study with ultraviolet measurements was performed. Fourier Transform Infrared measurements were carried out for molecular characterization. The releasing behavior of the drug exhibits a decrease and a subsequent increase in the release rate, as the acrylamide monomer increases. Characterization of the hydrogels has shown a competitive behavior between crosslinking with AAm acrylamide monomer or oligomerized version, depending on the amount added to prepare the hydrogels.

  12. Effect of temperature switchover on the degradation of antibiotic chloramphenicol by biocathode bioelectrochemical system.

    PubMed

    Kong, Deyong; Liang, Bin; Lee, Duu-Jong; Wang, Aijie; Ren, Nanqi

    2014-08-01

    Exposure to chloramphenicol (CAP), a chlorinated nitroaromatic antibiotic, can induce CAP-resistant bacteria/genes in diverse environments. A biocathode bioelectrochemical system (BES) was applied to reduce CAP under switched operational temperatures. When switching from 25 to 10°C, the CAP reduction rate (kCAP) and the maximum amount of the dechlorinated reduced amine product (AMCl, with no antibacterial activity) by the biocathode communities were both markedly decreased. The acetate and ethanol yield from cathodophilic microbial glucose fermentation (with release of electrons) was also reduced. Formation of the product AMCl was enhanced by the biocathode dechloridation reaction compared with that produced from pure electrochemical or microbial dechloridation processes. The electrochemical and morphological analyses of cathode biofilms demonstrated that some cathodophilic microbes could adapt to low temperature and play a key role in CAP degradation. The resilient biocathode BES has a potential for the treatment of CAP-containing wastewater in temperature fluctuating environments.

  13. Acute and chronic toxic effects of chloramphenicol on Scenedesmus obliquus and Chlorella pyrenoidosa.

    PubMed

    Zhang, Wei; Sun, Wenfang; An, Shuai; Xiong, Bang; Lin, Kuangfei; Cui, Xinhong; Guo, Meijin

    2013-08-01

    The acute and chronic toxicological effects of Chloramphenicol (CAP) on Scenedesmus obliquus and Chlorella pyrenoidosa are not well understood. The indoor experiments were carried to observe and analyze the CAP induced changes. Results of the observations have showed that CAP exposure could significantly inhibit the growth of Scenedesmus obliquus in almost all the treated groups, while Chlorella pyrenoidosa exhibited less sensitivity. Chlorophyll-a syntheses of Scenedesmus obliquus were all inhibited by CAP exposure, while Chlorella pyrenoidosa displayed obvious stimulation effect. Catalase (CAT) and Superoxide dismutase (SOD) activities of both algae were promoted in all the treatments. The experimental results indicated that the growth and Chlorophyll-a syntheses of Scenedesmus obliquus were more sensitive in response to CAP exposure than that of Chlorella pyrenoidosa. While for CAT and SOD activities, Chlorella pyrenoidosa showed more susceptible. This research provides a basic understanding of CAP toxicity to aquatic organisms.

  14. An Improved Electrochemical Aptasensor for Chloramphenicol Detection Based on Aptamer Incorporated Gelatine

    PubMed Central

    Hamidi-Asl, Ezat; Dardenne, Freddy; Blust, Ronny; De Wael, Karolien

    2015-01-01

    Because of the biocompatible properties of gelatine and the good affinity of aptamers for their targets, the combination of aptamer and gelatine type B is reported as promising for the development of biosensing devices. Here, an aptamer for chloramphenicol (CAP) is mixed with different types of gelatine and dropped on the surface of disposable gold screen printed electrodes. The signal of the CAP reduction is investigated using differential pulse voltammetry. The diagnostic performance of the sensor is described and a detection limit of 1.83 × 10−10 M is found. The selectivity and the stability of the aptasensor are studied and compared to those of other CAP sensors described in literature. PMID:25825978

  15. Chloramphenicol Derivatives as Antibacterial and Anticancer Agents: Historic Problems and Current Solutions

    PubMed Central

    Dinos, George P.; Athanassopoulos, Constantinos M.; Missiri, Dionissia A.; Giannopoulou, Panagiota C.; Vlachogiannis, Ioannis A.; Papadopoulos, Georgios E.; Papaioannou, Dionissios; Kalpaxis, Dimitrios L.

    2016-01-01

    Chloramphenicol (CAM) is the D-threo isomer of a small molecule, consisting of a p-nitrobenzene ring connected to a dichloroacetyl tail through a 2-amino-1,3-propanediol moiety. CAM displays a broad-spectrum bacteriostatic activity by specifically inhibiting the bacterial protein synthesis. In certain but important cases, it also exhibits bactericidal activity, namely against the three most common causes of meningitis, Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis. Resistance to CAM has been frequently reported and ascribed to a variety of mechanisms. However, the most important concerns that limit its clinical utility relate to side effects such as neurotoxicity and hematologic disorders. In this review, we present previous and current efforts to synthesize CAM derivatives with improved pharmacological properties. In addition, we highlight potentially broader roles of these derivatives in investigating the plasticity of the ribosomal catalytic center, the main target of CAM. PMID:27271676

  16. Malachite green and chloramphenicol in aquatic products from regions around Dongting Lake in Hunan, China.

    PubMed

    He, Jiang; Cui, Jingzhen

    2016-01-01

    Aquatic products are important sources of animal proteins in human diet, especially in developing countries. As such, the safety of aquatic products is of primary concern. In this study, a standard method is used to detect malachite green (MG) and chloramphenicol (CAP) and to analyse the contents of these banned chemicals in turtle, mandarin fish and grass carp sampled from the region surrounding Dongting Lake area in Hunan, China. Results showed that 10.6% of the samples were MG-positive, most of them turtles. CAP was found in 8.3% of the samples, mostly in mandarin fish. These data indicated that these banned substances are still used in the surveyed area. Hence, adequate strategies must be implemented by the local government to control these banned substances.

  17. Thermoadaptation-directed evolution of chloramphenicol acetyltransferase in an error-prone thermophile using improved procedures.

    PubMed

    Kobayashi, Jyumpei; Furukawa, Megumi; Ohshiro, Takashi; Suzuki, Hirokazu

    2015-07-01

    Enhancing the thermostability of thermolabile enzymes extends their practical utility. We previously demonstrated that an error-prone thermophile derived from Geobacillus kaustophilus HTA426 can generate mutant genes encoding enzyme variants that are more thermostable than the parent enzyme. Here, we used this approach, termed as thermoadaptation-directed enzyme evolution, to increase the thermostability of the chloramphenicol acetyltransferase (CAT) of Staphylococcus aureus and successfully generated a CAT variant with an A138T replacement (CAT(A138T)). This variant was heterologously produced, and its enzymatic properties were compared with those of the wild type. We found that CAT(A138T) had substantially higher thermostability than CAT but had comparable activities, showing that the A138T replacement enhanced protein thermostability without affecting the catalytic activity. Because variants CAT(A138S) and CAT(A138V), which were generated via in vitro site-directed mutagenesis, were more thermostable than CAT, the thermostability enhancement resulting from the A138T replacement can be attributed to both the presence of a hydroxyl group and the bulk of the threonine side chain. CAT(A138T) conferred chloramphenicol resistance to G. kaustophilus cells at high temperature more efficiently than CAT. Therefore, the gene encoding CAT(A138T) may be useful as a genetic marker in Geobacillus spp. Notably, CAT(A138T) generation was achieved only by implementing improved procedures (plasmid-based mutations on solid media); previous procedures (chromosome-based mutations in liquid media) were unsuccessful. This result suggests that this improved procedure is crucial for successful thermoadaptation-directed evolution in certain cases and increases the opportunities for generating thermostable enzymes.

  18. Evaluation of Amphotericin B and Chloramphenicol as Alternative Drugs for Treatment of Chytridiomycosis and Their Impacts on Innate Skin Defenses

    PubMed Central

    Holden, Whitney M.; Ebert, Alexander R.; Canning, Peter F.

    2014-01-01

    Chytridiomycosis, an amphibian skin disease caused by the emerging fungal pathogen Batrachochytrium dendrobatidis, has been implicated in catastrophic global amphibian declines. The result is an alarming decrease in amphibian diversity that is a great concern for the scientific community. Clinical trials testing potential antifungal drugs are needed to identify alternative treatments for amphibians infected with this pathogen. In this study, we quantified the MICs of chloramphenicol (800 μg/ml), amphotericin B (0.8 to 1.6 μg/ml), and itraconazole (Sporanox) (20 ng/ml) against B. dendrobatidis. Both chloramphenicol and amphotericin B significantly reduced B. dendrobatidis infection in naturally infected southern leopard frogs (Rana [Lithobates] sphenocephala), although neither drug was capable of complete fungal clearance. Long-term exposure of R. sphenocephala to these drugs did not inhibit antimicrobial peptide (AMP) synthesis, indicating that neither drug is detrimental to this important innate skin defense. However, we observed that chloramphenicol, but not amphotericin B or itraconazole, inhibited the growth of multiple R. sphenocephala skin bacterial isolates in vitro at concentrations below the MIC against B. dendrobatidis. These results indicate that treatment with chloramphenicol might dramatically alter the protective natural skin microbiome when used as an antifungal agent. This study represents the first examination of the effects of alternative antifungal drug treatments on amphibian innate skin defenses, a crucial step to validating these treatments for practical applications. PMID:24771024

  19. Investigation of enrofloxacin and chloramphenicol residues in broiler chickens carcasses collected from local markets of tabriz, northwestern iran.

    PubMed

    Ebrahimzadeh Attari, Vahideh; Mesgari Abbasi, Mehran; Abedimanesh, Nasim; Ostadrahimi, Alireza; Gorbani, Abolfazl

    2014-01-01

    The present study was aimed to determine the residual amounts of chloramphenicol and enrofloxacin in broiler chickens muscle and liver sam-ples gathered from local markets of Tabriz City, northwestern Iran. Ninety broiler chickens carcasses were collected from different local markets of Tabriz, during July/August 2013. Random samples of thigh and breast muscle and liver were gathered and kept at -80(°)C until analyzes. The samples were then assayed using enzyme-linked immunosorbent assay (ELISA) according to the protocol of each antibiotic kit. Data were statistically analyzed using the computer program SAS 9.1. Eighty two samples (91/1 %) contained residues of enrofloxacin, alt-hough mean (±SD)of enrofloxacin concentration was lower than the European Union maximum residue limits(MRLs) value (P<0.001). Moreover, 28 (31/1 %) had detectable concentrations of chloramphenicol while it was not defined any MRLs value for chloramphenicol because its using has been forbidden in food animals. The frequency of contamination with enrofloxacin was considerable for the analyzed samples. Furthermore, the existence of chloramphenicol in almost one third of samples seems to be a public health threat due to its illegal use in food animals including poultry.

  20. Construction and use of a replication-competent human immunodeficiency virus (HIV-1) that expresses the chloramphenicol acetyltransferase enzyme.

    PubMed Central

    Terwilliger, E F; Godin, B; Sodroski, J G; Haseltine, W A

    1989-01-01

    The construction and properties of an infectious human immunodeficiency virus (HIV) that expresses the bacterial gene chloramphenicol acetyltransferase are described. This virus can be used in vitro to screen for drugs that inhibit HIV infection. The marked virus may also be used to trace the routes of infection from the site of inoculation in animal experiments. Images PMID:2726755

  1. Investigations into the basis of chloramphenicol and tetracycline resistance in Staphylococcus intermedius isolates from cases of pyoderma in dogs.

    PubMed

    Kim, T J; Na, Y R; Lee, J I

    2005-04-01

    A total of 160 Staphylococcus intermedius isolates were recovered from cases of pyoderma in 2002 and were examined for susceptibility to 13 different antimicrobial agents. Ninety per cent (144) of the isolates were resistant to tetracycline, derivatives of which have been used until recently, and 18% (29) were resistant to chloramphenicol which was banned from use 13 years ago. The presence of genes encoding chloramphenicol acetyltransferase (CAT) and tetracycline resistance (tet); tet(K), (L), (M), and (O) were determined by PCR in the 29 chloramphenicol and tetracycline resistant isolates. Seventeen (59%) isolates contained the cat gene while 12 (41%) isolates did not carry the cat gene, implying there may be other genes for chloramphenicol resistance that were not detected by the primers (primer set 1) used in this study. The tet(M) gene was found in 28 (97%) of the resistant S. intermedius isolates, but none contained the tet(O) gene. All 29 isolates carried one or two tet genes; tet(K), (L), and (M), with four different distribution patterns. New PCR products, a 1.1 kb product using primer set 1 and a 0.2 kb product using primer set 2, were cloned and sequenced. A 904 bp fragment of S. aureus plamid pS194, including sequence from the streptomycin adenyltransferase gene (804 bp), was found inserted into the terminal region of the cat gene (GenBank accession no. AY604739), whilst the sequence of 0.2 kb was previously unpublished.

  2. The Identification of Intrinsic Chloramphenicol and Tetracycline Resistance Genes in Members of the Bacillus cereus Group (sensu lato)

    PubMed Central

    Glenwright, Helen; Pohl, Susanne; Navarro, Ferran; Miro, Elisenda; Jiménez, Guillermo; Blanch, Anicet R.; Harwood, Colin R.

    2017-01-01

    Bacillus toyonensis strain BCT-7112T (NCIMB 14858T) has been widely used as an additive in animal nutrition for more than 30 years without reports of adverse toxigenic effects. However, this strain is resistant to chloramphenicol and tetracycline and it is generally considered inadvisable to introduce into the food chain resistance determinants capable of being transferred to other bacterial strains, thereby adding to the pool of such determinants in the gastro-enteric systems of livestock species. We therefore characterized the resistance phenotypes of this strain and its close relatives to determine whether they were of recent origin, and therefore likely to be transmissible. To this end we identified the genes responsible for chloramphenicol (catQ) and tetracycline (tetM) resistance and confirmed the presence of homologs in other members of the B. toyonensis taxonomic unit. Unexpectedly, closely related strains encoding these genes did not exhibit chloramphenicol and tetracycline resistance phenotypes. To understand the differences in the behaviors, we cloned and expressed the genes, together with their upstream regulatory regions, into Bacillus subtilis. The data showed that the genes encoded functional proteins, but were expressed inefficiently from their native promoters. B. toyonensis is a taxonomic unit member of the Bacillus cereus group (sensu lato). We therefore extended the analysis to determine the extent to which homologous chloramphenicol and tetracycline resistance genes were present in other species within this group. This analysis revealed that homologous genes were present in nearly all representative species within the B. cereus group (sensu lato). The absence of known transposition elements and the observations that they are found at the same genomic locations, indicates that these chloramphenicol and tetracycline resistance genes are of ancient origin and intrinsic to this taxonomic group, rather than recent acquisitions. In this context we

  3. The Identification of Intrinsic Chloramphenicol and Tetracycline Resistance Genes in Members of the Bacillus cereus Group (sensu lato).

    PubMed

    Glenwright, Helen; Pohl, Susanne; Navarro, Ferran; Miro, Elisenda; Jiménez, Guillermo; Blanch, Anicet R; Harwood, Colin R

    2016-01-01

    Bacillus toyonensis strain BCT-7112(T) (NCIMB 14858(T)) has been widely used as an additive in animal nutrition for more than 30 years without reports of adverse toxigenic effects. However, this strain is resistant to chloramphenicol and tetracycline and it is generally considered inadvisable to introduce into the food chain resistance determinants capable of being transferred to other bacterial strains, thereby adding to the pool of such determinants in the gastro-enteric systems of livestock species. We therefore characterized the resistance phenotypes of this strain and its close relatives to determine whether they were of recent origin, and therefore likely to be transmissible. To this end we identified the genes responsible for chloramphenicol (catQ) and tetracycline (tetM) resistance and confirmed the presence of homologs in other members of the B. toyonensis taxonomic unit. Unexpectedly, closely related strains encoding these genes did not exhibit chloramphenicol and tetracycline resistance phenotypes. To understand the differences in the behaviors, we cloned and expressed the genes, together with their upstream regulatory regions, into Bacillus subtilis. The data showed that the genes encoded functional proteins, but were expressed inefficiently from their native promoters. B. toyonensis is a taxonomic unit member of the Bacillus cereus group (sensu lato). We therefore extended the analysis to determine the extent to which homologous chloramphenicol and tetracycline resistance genes were present in other species within this group. This analysis revealed that homologous genes were present in nearly all representative species within the B. cereus group (sensu lato). The absence of known transposition elements and the observations that they are found at the same genomic locations, indicates that these chloramphenicol and tetracycline resistance genes are of ancient origin and intrinsic to this taxonomic group, rather than recent acquisitions. In this context

  4. Aptasensing of chloramphenicol in the presence of its analogues: reaching the maximum residue limit.

    PubMed

    Pilehvar, Sanaz; Mehta, Jaytry; Dardenne, Freddy; Robbens, Johan; Blust, Ronny; De Wael, Karolien

    2012-08-07

    A novel, label-free folding induced aptamer-based electrochemical biosensor for the detection of chloramphenicol (CAP) in the presence of its analogues has been developed. CAP is a broad-spectrum antibiotic that has lost its favor due to its serious adverse toxic effects on human health. Aptamers are artificial nucleic acid ligands (ssDNA or RNA) able to specifically recognize a target such as CAP. In this article, the aptamers are fixed onto a gold electrode surface by a self-assembly approach. In the presence of CAP, the unfolded ssDNA on the electrode surface changes to a hairpin structure, bringing the target molecules close to the surface and triggering electron transfer. Detection limits were determined to be 1.6 × 10(-9) mol L(-1). In addition, thiamphenicol (TAP) and florfenicol (FF), antibiotics with a structure similar to CAP, did not influence the performance of the aptasensor, suggesting a good selectivity of the CAP-aptasensor. Its simplicity and low detection limit (because of the home-selected aptamers) suggest that the electrochemical aptasensor is suitable for practical use in the detection of CAP in milk samples.

  5. Hydrolysis of amphenicol and macrolide antibiotics: Chloramphenicol, florfenicol, spiramycin, and tylosin.

    PubMed

    Mitchell, Shannon M; Ullman, Jeffrey L; Teel, Amy L; Watts, Richard J

    2015-09-01

    Antibiotics that enter the environment can present human and ecological health risks. An understanding of antibiotic hydrolysis rates is important for predicting their environmental persistence as biologically active contaminants. In this study, hydrolysis rates and Arrhenius constants were determined as a function of pH and temperature for two amphenicol (chloramphenicol and florfenicol) and two macrolide (spiramycin and tylosin) antibiotics. Antibiotic hydrolysis rates in pH 4-9 buffer solutions at 25°C, 50°C, and 60°C were quantified, and degradation products were characterized. All of the antibiotics tested remained stable and exhibited no observable hydrolysis under ambient conditions typical of aquatic ecosystems. Acid- and base-catalyzed hydrolysis occurred at elevated temperatures (50-60°C), and hydrolysis rates increased considerably below pH 5 and above pH 8. Hydrolysis rates also increased approximately 1.5- to 2.9-fold for each 10°C increase in temperature. Based on the degradation product masses found, the functional groups that underwent hydrolysis were alkyl fluoride, amide, and cyclic ester (lactone) moieties; some of the resultant degradation products may remain bioactive, but to a lesser extent than the parent compounds. The results of this research demonstrate that amphenicol and macrolide antibiotics persist in aquatic systems under ambient temperature and pH conditions typical of natural waters. Thus, these antibiotics may present a risk in aquatic ecosystems depending on the concentration present. Copyright © 2015. Published by Elsevier Ltd.

  6. Distribution and chloramphenicol in the bovine genital tract and pharmacokinetic studies of florfenicol in cattle

    SciTech Connect

    Bretzlaff, K.N.

    1986-01-01

    The objectives were to investigate selected aspects of the distribution of chloramphenicol (CAP) in the bovine genital tract and to conduct preliminary pharmacologic studies with florfenicol (FLO), a fluorinated analogue of thiamphenicol, in cattle. After 8 hours' continuous intravenous (IV) infusion of CAP to 7 postpartum cows, steady state plasma-to-genital tissue ratios of CAP were approximately 3. After intrauterine infusion of 20 mg CAP/kg to 3 postpartum cows, approximately 40% of the dose was absorbed into the bloodstream. Tissue concentrations were high at 8 hour postdosing in tissues lining the uterine lumen but were below desired therapeutic concentrations in the myometrium of 2 of the cows. Eighty cows with retained fetal membranes (RFM) were assigned to receive on the following treatments: (1) removal of membranes only; (2) removal plus CAP; (3) nonremoval; (4) nonremoval plus CAP. CAP treatment consisted of 5 g administered IU twice daily for 3 days. The majority of cows in all groups acquired endometritis, although CAP reduced the prevalence and severity of the disease. A quantitative assay for FLO in plasma was developed and validated on a high performance liquid chromatographic (HPLC) system. The pharmacokinetics of FLO determined after IV administration of 50 mg FLO/kg to 5 cows were best described by a three-compartment model. FLO was approximately 18% bound to plasma proteins as determined by equilibrium dialysis and ultrafiltration. In an in vitro system, 5, 125, or 1000 ug/ml of CAP had no effect on neutrophils from 6 cows.

  7. Application of the chloramphenicol acetyltransferase (CAT) diffusion assay to transgenic plant tissues.

    PubMed

    Peach, C; Velten, J

    1992-02-01

    Chloramphenicol acetyltransferase (CAT) activity was quantified in crude extracts from tobacco callus tissues using a modification of a previously reported diffusion assay. We describe here the alterations necessary in applying this rapid and simple assay procedure to plant materials. Due to the high concentration of nonspecific oxidases present in most plant tissues, some type of protective agent is required to maintain enzyme activity. We have tested beta-mercaptoethanol, cysteine, dithiothreitol, ascorbic acid and polyvinyl pyrrolidone as protective agents within the initial extraction buffer. We also investigated the effect of heat (60 degrees C, 10 min) and 5 mM EDTA on CAT activity. The highest CAT activity was obtained using 5 mM cysteine plus 5 mM EDTA in 40 mM Tris-HCl (pH 7.8) as the initial extraction buffer followed by a heat treatment. Using this buffer, CAT activity was stable on ice for more than two hours. In our hands, total acetyl-coenzyme A concentration within the assay mixture was found to be saturating at 250 microM and the Km determined to be 100 microM. Assays performed using the same crude plant extract indicate that 1) duplicate assays show less than 1.5% variation in activities and 2) CAT activity increases linearly with respect to volume of extract used.

  8. Conjugation with polyamines enhances the antibacterial and anticancer activity of chloramphenicol

    PubMed Central

    Kostopoulou, Ourania N.; Kouvela, Ekaterini C.; Magoulas, George E.; Garnelis, Thomas; Panagoulias, Ioannis; Rodi, Maria; Papadopoulos, Georgios; Mouzaki, Athanasia; Dinos, George P.; Papaioannou, Dionissios; Kalpaxis, Dimitrios L.

    2014-01-01

    Chloramphenicol (CAM) is a broad-spectrum antibiotic, limited to occasional only use in developed countries because of its potential toxicity. To explore the influence of polyamines on the uptake and activity of CAM into cells, a series of polyamine–CAM conjugates were synthesized. Both polyamine architecture and the position of CAM-scaffold substitution were crucial in augmenting the antibacterial and anticancer potency of the synthesized conjugates. Compounds 4 and 5, prepared by replacement of dichloro-acetyl group of CAM with succinic acid attached to N4 and N1 positions of N8,N8-dibenzylspermidine, respectively, exhibited higher activity than CAM in inhibiting the puromycin reaction in a bacterial cell-free system. Kinetic and footprinting analysis revealed that whereas the CAM-scaffold preserved its role in competing with the binding of aminoacyl-tRNA 3′-terminus to ribosomal A-site, the polyamine-tail could interfere with the rotatory motion of aminoacyl-tRNA 3′-terminus toward the P-site. Compared to CAM, compounds 4 and 5 exhibited comparable or improved antibacterial activity, particularly against CAM-resistant strains. Compound 4 also possessed enhanced toxicity against human cancer cells, and lower toxicity against healthy human cells. Thus, the designed conjugates proved to be suitable tools in investigating the ribosomal catalytic center plasticity and some of them exhibited greater efficacy than CAM itself. PMID:24939899

  9. Occurrence of chloramphenicol in cereal straw in north-western Europe

    PubMed Central

    Nordkvist, Erik; Zuidema, Tina; Herbes, Rik G.; Berendsen, Bjorn J.A.

    2016-01-01

    ABSTRACT Two surveys are presented of straw analysed for naturally occurring chloramphenicol (CAP), a drug banned for use in food-producing animals. In the first study, CAP was analysed by LC-MS/MS and detected in 37 out of 105 straw samples originating from the Netherlands, France, the UK, Germany and Denmark. The highest level found was 6.3 µg kg−1, the average 0.6 µg kg−1 and the median 0.2 µg kg−1. The second study included a method comparison between ELISA and LC-MS/MS and a survey of CAP in cereal straw sampled at farms in all areas of Sweden. A total of 215 samples were screened by ELISA and a subset of 26 samples was also analysed by LC-MS/MS. Fifty-four of the samples contained more than 1 µg kg−1 CAP and the highest level found was 32 µg kg−1 (confirmed by LC-MS/MS). The highest contents of CAP in this study were allocated to the Baltic sea coast in the south-eastern part of Sweden (the county of Skåne and the Baltic Sea isle of Gotland). These results indicate a high incidence of CAP in straw in north-west Europe and have a severe impact on the enforcement of European Union legislation. PMID:27101357

  10. Direct detection of chloramphenicol in honey by neutral desorption-extractive electrospray ionization mass spectrometry.

    PubMed

    Huang, X Y; Fang, X W; Zhang, X; Dai, X M; Guo, X L; Chen, H W; Luo, L P

    2014-11-01

    Herein, we constructed a platform of neutral desorption-extractive electrospray ionization mass spectrometry (ND-EESI-MS) for direct and rapid detection of chloramphenicol (CAP) in honey samples diluted with methanol. Under the optimized working conditions, the quantitative information of CAP residues was acquired effectively by EESI-Ion Trap MS (n) . Using heated methanol-N2 as spray reagent, we reduced the limit of determination (LOD) from 73.3 ng/mL to 0.3 ng/mL, and the CAP detection is linear in the range of 1-5000 ng/mL (R = 0.9947). For the honey samples with CAP of 10, 100, and 1000 ng/mL, the recoveries were 133.0, 80.6, and 101.1%, and the relative standard deviations were 5.96, 8.82, and 8.71%, respectively. The reproducibility assays showed the stability of this method. Therefore, this ND-EESI-MS method is powerful for direct, rapid, and quantitative CAP analysis in honey samples with high sensitivity, precision, and specificity.

  11. Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin.

    PubMed

    Chen, Huilun; Rao, Honghao; He, Pengzhen; Qiao, Yongxiang; Wang, Fei; Liu, Haijun; Cai, Minmin; Yao, Jun

    2014-10-01

    Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet-visible (UV-Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP-HSA complex, and the binding constant was determined to be 3.196 × 10(4) L mol(-1) at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.

  12. Modification by chloramphenicol of diethyl sulphate-induced male recombination frequency in Drosophila melanogaster.

    PubMed

    Miglani, G S; Kaur, N P

    1995-06-01

    To study the effect of chloramphenicol (CPL, an inhibitor of protein synthesis) on diethyl sulphate (DES, a potent mutagen) induced male recombination frequency, the F1 (+/aristaless dumpy black cinnabar, al dp b cn) larvae of D. melanogaster were given a pre- or post-treatment of CPL with DES during the first or second half of larval life. In order to determine sensitivity of different germ cell stages to the induction and modification of male recombination frequency, five 3-day broods were taken from every F1 male. DES showed toxic effect on egg-to-adult development. DES was found to be a potent recombinogen. Several cases of non-reciprocal male recombination were recorded. The most frequent recombinant phenotype observed was b cn followed by cn and al. Majority of the recombinants appeared in clusters suggesting their pre-meiotic origin. DES produced male recombination at a stage where only primary spermatocytes were present in the larval testes. CPL when given as a pre- or post-treatment with DES revealed highest frequency of male recombination in broods that represented effect of treatment on spermatogonia predominantly. CPL enhanced the overall level of male recombination produced by DES in both pre- and post-treatments. The results suggested the role of protein synthesis in induction of male recombination in D. melanogaster. In addition, the present experiments give a methodology of enhancing the frequency of chemically-induced male recombination.

  13. The changes in pharmacokinetics and conjugation of chloramphenicol in irradiated rats.

    PubMed

    Stoklasová, A; Krízala, J; Ledvina, M

    1978-11-01

    In the serum and the liver of rats levels of chloramphenicol (CAP) following its i.v. administration (200 mg/kg) in the control groups and in the rats irradiated with whole-body air exposure to 500 R were determined with spectrophotometric methods. The CAP-levels in the serum increased in the group of rats 3 days after irradiation, but only during the 1st hour. At later time intervals the values were lower than in the controls. This decrease at the 60th min is striking even in the groups 6 and 9 days after exposure. Free CAP in the liver of rats irradiated 6 and 9 days before was lower at interval 30 min after CAP-administration, but the group irradiated 9 days before was unaltered. However, 120 min after CAP-administration the values of free CAP decreased at all intervals investigated following the irradiation. The levels of conjugated CAP in the liver of the rats 3 and 6 days after exposure were lower than in controls in both intervals after drug administration; but in rats 9 days after irradiation they increased. Our results indicate that the kinetics of CAP is altered and corresponding changes in its conjugation are effected under the condition of acute radiation syndrome.

  14. A series of shuttle vectors using chloramphenicol acetyltransferase as a reporter enzyme in yeast.

    PubMed

    Mannhaupt, G; Pilz, U; Feldmann, H

    1988-07-30

    Reports from numerous laboratories have shown that the gene coding for the bacterial enzyme chloramphenicol-3-O-acetyltransferase can be used as a reporter gene (cat) in mammalian and plant systems to analyze gene activity at the transcriptional level when combined with endogenous regulatory signals; the enzyme activity can be quantified by a chromatographic or a photometric assay. To adapt this simple and highly sensitive test for the yeast system, we constructed a series of yeast vectors containing the cat gene together with selectable markers for Escherichia coli and yeast; integrating, autonomously replicating and centromere-carrying plasmids were used. We show that the cat gene lacking the endogenous promoter is expressed at low levels in yeast transformants. To demonstrate functional expression of the cat gene placed under the control of a yeast promoter, we chose the PHO5 regulatory region. We found that cat expression was induced via the PHO5 promoter in a manner as observed for the endogenous PHO5 gene, whereas in the repressed state cat expression remained low. Using these vectors, it should be feasible to analyze other sequences conferring promoter activity or other control functions in yeast.

  15. Rapid Detection of Chloramphenicol Residues in Aquatic Products Using Colloidal Gold Immunochromatographic Assay

    PubMed Central

    Zhou, Chennan; Zhang, Xueyin; Huang, Xinxin; Guo, Xishan; Cai, Qiang; Zhu, Songming

    2014-01-01

    A colloidal gold immunochromatographic assay (GICA) was developed for rapid detection of chloramphenicol (CAP) residues in aquatic products. A nitrocellulose (NC) membrane was used as the carrier, and the polyclonal CAP antibody was used as the marker protein. The average diameter of as-prepared colloidal gold nanoparticles (AuNPs) was about 20 nm. The optimal pH value of colloidal gold solutions and the amount of the antibody of CAP were 8.0 and 7.2 μg/mL, respectively. The CAP antibody was immobilized onto the conjugate pad after purification. The CAP conjugate and goat anti-rabbit IgG (secondary antibody) were coated onto the NC membrane. Next, the non-specific sites were blocked with 1% bovine serum albumin. The minimum detectable concentration of CAP in standard solution is 0.5 ng/mL, with good reproducibility. For the real samples from crucian carps injected with a single-dose of CAP in the dorsal muscles, the minimum detectable concentration of CAP residues was 0.5 μg/kg. The chromatographic analysis time was less than 10 min, and the strip had a long storage lifetime of more than 90 days at different temperatures. The strips provide a means for rapid detection of CAP residues in aquatic products. PMID:25412221

  16. Rapid detection of chloramphenicol residues in aquatic products using colloidal gold immunochromatographic assay.

    PubMed

    Zhou, Chennan; Zhang, Xueyin; Huang, Xinxin; Guo, Xishan; Cai, Qiang; Zhu, Songming

    2014-11-18

    A colloidal gold immunochromatographic assay (GICA) was developed for rapid detection of chloramphenicol (CAP) residues in aquatic products. A nitrocellulose (NC) membrane was used as the carrier, and the polyclonal CAP antibody was used as the marker protein. The average diameter of as-prepared colloidal gold nanoparticles (AuNPs) was about 20 nm. The optimal pH value of colloidal gold solutions and the amount of the antibody of CAP were 8.0 and 7.2 μg/mL, respectively. The CAP antibody was immobilized onto the conjugate pad after purification. The CAP conjugate and goat anti-rabbit IgG (secondary antibody) were coated onto the NC membrane. Next, the non-specific sites were blocked with 1% bovine serum albumin. The minimum detectable concentration of CAP in standard solution is 0.5 ng/mL, with good reproducibility. For the real samples from crucian carps injected with a single-dose of CAP in the dorsal muscles, the minimum detectable concentration of CAP residues was 0.5 µg/kg. The chromatographic analysis time was less than 10 min, and the strip had a long storage lifetime of more than 90 days at different temperatures. The strips provide a means for rapid detection of CAP residues in aquatic products.

  17. Electrocatalytic determination of chloramphenicol based on molybdenum disulfide nanosheets and self-doped polyaniline.

    PubMed

    Yang, Ruirui; Zhao, Jinlong; Chen, Meijing; Yang, Tao; Luo, Shizhong; Jiao, Kui

    2015-01-01

    In this paper, a novel molybdenum disulfide (MoS2) intercalated by self-doped polyaniline (SPAN) via ultrasonic exfoliating method was prepared to show outstanding conductivity and synergistic electrocatalytic activity using chloramphenicol (CAP) as a case. In the ultrasonic process, due to the strong π-π(*) stacking interaction and electrostatic repulsion, the negatively charged SPAN served as an intercalator to result in few-layers MoS2 nanosheets, which were exfoliated from bulk MoS2. This nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy and differential pulse voltammetry. The obtained nanocomposite owns large conjugated structure and rich negative charge, which can improve the adsorption of conjugate structured CAP with the detection range from 0.1 to 1000 μmol L(-1). The results also showed that the electrocatalytic responses were further affected by the mass ratio of SPAN-MoS2 and the ultrasonication time. Our electrocatalytic platform could be further applied in the adsorption and detection of other positively charged biomolecules or aromatic molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Response of Nigerian farmers to a questionnaire on chloramphenicol application in commercial layers.

    PubMed

    Omeiza, Gabriel K; Kabir, Junaidu; Mamman, Mohammed; Ibrahim, Hajara; Fagbamila, Idowu O

    2012-01-01

    The authors assessed the occurrence of chloramphenicol (CAP) residues in commercial eggs. Of the 105 farmers surveyed for the use of CAP, 35 (33.3%) and 70 (66.7%) responded regarding their awareness or complete lack of awareness of the legislation that stipulates the use of CAP in food animals, including poultry, respectively. Only 28 (26.7%) of respondent farmers were aware that CAP was one of the drugs that is not recommended for use in food animals. Amongst the farms surveyed in the preliminary phase of this study, 24 were randomly sampled for further investigation, of which 21 (20.0%) admitted the use of CAP in forms of human and veterinary preparations, while 15 (62.5%) admitted the use of human CAP preparation only. The presence of antimicrobial residues was confirmed using specific thin-layer chromatography (STLC) in 8 out of 144 pooled egg samples (10 eggs per sample). The only positive CAP sample was identified on a farm that adopted the use of a human CAP preparation.

  19. Occurrence of chloramphenicol in cereal straw in north-western Europe.

    PubMed

    Nordkvist, Erik; Zuidema, Tina; Herbes, Rik G; Berendsen, Bjorn J A

    2016-05-01

    Two surveys are presented of straw analysed for naturally occurring chloramphenicol (CAP), a drug banned for use in food-producing animals. In the first study, CAP was analysed by LC-MS/MS and detected in 37 out of 105 straw samples originating from the Netherlands, France, the UK, Germany and Denmark. The highest level found was 6.3 µg kg(-1), the average 0.6 µg kg(-1) and the median 0.2 µg kg(-1). The second study included a method comparison between ELISA and LC-MS/MS and a survey of CAP in cereal straw sampled at farms in all areas of Sweden. A total of 215 samples were screened by ELISA and a subset of 26 samples was also analysed by LC-MS/MS. Fifty-four of the samples contained more than 1 µg kg(-1) CAP and the highest level found was 32 µg kg(-1) (confirmed by LC-MS/MS). The highest contents of CAP in this study were allocated to the Baltic sea coast in the south-eastern part of Sweden (the county of Skåne and the Baltic Sea isle of Gotland). These results indicate a high incidence of CAP in straw in north-west Europe and have a severe impact on the enforcement of European Union legislation.

  20. An ultrasensitive chemiluminescence immunoassay of chloramphenicol based on gold nanoparticles and magnetic beads.

    PubMed

    Tao, Xiaoqi; Jiang, Haiyang; Yu, Xuezhi; Zhu, Jinghui; Wang, Xia; Wang, Zhanhui; Niu, Lanlan; Wu, Xiaoping; Shen, Jianzhong

    2013-05-01

    A competitive, direct, chemiluminescent immunoassay based on a magnetic beads (MBs) separation and gold nanoparticles (AuNPs) labelling technique to detect chloramphenicol (CAP) has been developed. Horseradish peroxidase (HRP)-labelled anti-CAP monoclonal antibody conjugated with AuNPs and antigen-immobilized MBs were prepared. After optimization parameters of immunocomplex MBs, the IC50 values of chemiluminescence magnetic nanoparticles immunoassay (CL-MBs-nano-immunoassay) were 0.017 µg L(-1) for extract method I and 0.17 µg L(-1) for extract method II. The immunoassay with two extract methods was applied to detect CAP in milk. Comparison of these two extract methods showed that extract method I was advantageous in better sensitivity, in which the sensitivity was 10 times compared to that of extract method II, while extract method II was superior in simple operation, suitable for high throughout screen. The recoveries were 86.7-98.0% (extract method I) and 80.0-103.0% (extract method II), and the coefficients of variation (CVs) were all <15%. The satisfactory recovery with both extract methods and high correlation with traditional ELISA kit in milk system confirmed that the immunomagnetic assay based on AuNPs exhibited promising potential in rapid field screening for trace CAP analysis. Copyright © 2013 John Wiley & Sons, Ltd.

  1. A gel-based visual immunoassay for non-instrumental detection of chloramphenicol in food samples.

    PubMed

    Yuan, Meng; Sheng, Wei; Zhang, Yan; Wang, Junping; Yang, Yijin; Zhang, Shuguang; Goryacheva, Irina Yu; Wang, Shuo

    2012-11-02

    A gel-based non-instrumental immuno-affinity assay was developed for the rapid screening of chloramphenicol (CAP) in food samples with the limit of detection (LOD) of 1 μg L(-1). The immuno-affinity test column (IATC) consisted of a test layer containing anti-CAP antibody coupled gel, and a control layer with anti-HRP antibody coupled gel. Based on the direct competitive immuno-reaction and the horseradish peroxidase enzymatic reaction, the test results could be evaluated visually. Basically, blue color development represented the negative results, while the absence of color development represented the positive results. In this study, CAP spiked samples of raw milk, pasteurized milk, UHT milk, skimmed milk powder, acacia honey, date honey, fish and shrimp were tested. Little or none sample pretreatment was required for this assay. The whole procedure was completed within 10min. In conclusion, the gel-based immuno-affinity test is a simple, rapid, and promising on-site screening method for CAP residues in food samples, with no instrumental requirement. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Highly sensitive electrochemical sensor for chloramphenicol based on MOF derived exfoliated porous carbon.

    PubMed

    Xiao, Lili; Xu, Ruiyu; Yuan, Qunhui; Wang, Fu

    2017-05-15

    Benefit from the advantages in costless, simplicity and efficiency, solvent exfoliation has been widely used in preparation of two-dimensional nanosheets with enhanced performances in electronics, photonics, and catalysis. In this work, solvent exfoliation was first applied to prepare exfoliated porous carbon (EPC) from an isoreticular metal-organic framework-8 (IRMOF-8) derived porous carbon (DPC). The obtained EPC with high surface area (1854m(2)g(-1)) and improved dispersibility was used as electrode modifier for glassy carbon electrode (GCE) in square wave voltammetry (SWV) detection of chloramphenicol (CAP). The sensitivity of EPC modified GCE (EPC/GCE) was greatly improved in compare with that of the DPC modification. The corresponding linear ranges are 1×10(-8)-1×10(-6)molL(-1) and 1×10(-6)-4×10(-6)molL(-1). The detection limit was calculated to be 2.9×10(-9)molL(-1) (at a signal-to-noise ratio of 3, S/N=3). In addition, the proposed sensor was successfully applied in the analysis of CAP in honey and achieved satisfying recovery.

  3. Engineered "hot" core-shell nanostructures for patterned detection of chloramphenicol.

    PubMed

    Yan, Wenjing; Yang, Longping; Zhuang, Hong; Wu, Haizhou; Zhang, Jianhao

    2016-04-15

    In this study, we described a novel method for highly sensitive and specific detection of chloramphenicol (CAP) based on engineered "hot" Au core-Ag shell nanostructures (Au@Ag NSs). Cy5-labeled DNA aptamer was embedded between the Au and Ag layers as a signal generator and target-recognition element, to fabricate uniform Au@Ag NSs with unexpected strong and stable SERS signals. The presented CAP can specifically bind to the DNA aptamer by forming an aptamer-CAP conjugate, and cause greatly decreased SERS signals of Au@Ag NSs. By using this method, we were able to detect as low as 0.19 pg mL(-1) of CAP with high selectivity, which is much lower than those previously reported biosensors. Compared with the other SERS sensors that attached a dye in the outer layer of nanoparticles, this method exhibits excellent sensitivity and has the potential to significantly improve stability and reproducibility of SERS-based detection techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Direct competitive chemiluminescence immunoassays based on gold-coated magnetic particles for detection of chloramphenicol.

    PubMed

    Liang, Xiaohui; Fang, Xiangyi; Yao, Manwen; Yang, Yucong; Li, Junfeng; Liu, Hongjun; Wang, Linyu

    2016-02-01

    Direct competitive chemiluminescence immunoassays (CLIA) based on gold-coated magnetic nanospheres (Au-MNPs) were developed for rapid analysis of chloramphenicol (CAP). The Au-MNPs were modified with carboxyl groups and amino groups by 11-mercaptoundecanoic acid (MUA) and cysteamine respectively, and then were respectively conjugated with CAP base and CAP succinate via an activating reaction using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). NSP-DMAE-NHS, a new and effective luminescence reagent, was employed to label anti-CAP antibody (mAb) as a tracer in direct CLIA for CAP detection using a 'homemade' luminescent measurement system that was set up with a photomultiplier tube (PMT) and a photon counting unit linked to a computer. The sensitivities and limits of detection (LODs) of the two methods were obtained and compared according to the inhibition curves. The 50% inhibition concentration (IC50 ) values of the two methods were about 0.044 ng/mL and 0.072 ng/mL respectively and LODs were approximately 0.001 ng/mL and 0.006 ng/mL respectively. To our knowledge, they were much more sensitive than any traditional enzyme-linked immunosorbent assay (ELISA) ever reported. Moreover, the new luminescence reagent NSP-DMAE-NHS is much more sensitive and stable than luminol and its derivatives, contributing to the sensitivity enhancement.

  5. Chloramphenicol stereoisomers need to be distinguished: consequences observed from a proficiency test.

    PubMed

    Sykes, Mark; Czymai, Tobias; Hektor, Thomas; Sharman, Matthew; Knaggs, Michael

    2017-04-01

    Although the use of chloramphenicol (CAP) as a veterinary drug is banned in the European Union and many other countries, monitoring for CAP residues in food is routine. Positive detections are few, but taken extremely seriously. European Union laboratories analysing for CAP should validate methods according to European Commission Decision 2002/657/EC, must be accredited to ISO 17025, and will generally participate in proficiency testing (PT) schemes, such as those offered by the Food Analysis Performance Assessment Scheme (FAPAS®). The FAPAS PTs aim to cover a wide range of relevant matrices including honey, prawns, fish, milk and kidney. Test materials are prepared either by animal dosing studies or by spiking raw matrix. The most common method reported by FAPAS participants used to screen for CAP residues is LC-MS/MS, but ELISA kits are increasingly being used. A recent PT round highlighted that the result obtained might be correlated with the type of analytical method being employed. Follow-up investigations have demonstrated that some of these variations in data are a function of the different stereoisomeric forms of CAP. This paper discusses the implication of this research on method validation requirements and European Union legislation.

  6. In vitro expression of a Tn9-derived chloramphenicol acetyltransferase gene fusion by using a Bacillus subtilis system.

    PubMed Central

    Zaghloul, T I; Doi, R H

    1987-01-01

    A coupled in vitro protein-synthesizing system has been developed with components derived totally from Bacillus subtilis. The system synthesized specific gene products from various exogenous DNA templates, including B. subtilis phage phi 29, plasmid pUB110, and a heterologous B. subtilis-Escherichia coli gene fusion containing the transposon Tn9-derived chloramphenicol acetyltransferase (cat) gene. The gene fusion product was able to show CAT activity, bind specifically to a Sephacryl-chloramphenicol column, and react immunologically against anti-CAT antiserum. The fidelity of this in vitro system was demonstrated by the synthesis of gene products identical to that made in vivo. We suggest that this system may be used to study the regulation of gene expression in vitro. Images PMID:3102458

  7. Nucleotide sequence and phylogeny of a chloramphenicol acetyltransferase encoded by the plasmid pSCS7 from Staphylococcus aureus.

    PubMed

    Schwarz, S; Cardoso, M

    1991-08-01

    The nucleotide sequence of the chloramphenicol acetyltransferase gene (cat) and its regulatory region, encoded by the plasmid pSCS7 from Staphylococcus aureus, was determined. The structural cat gene encoded a protein of 209 amino acids, which represented one monomer of the enzyme chloramphenicol acetyltransferase (CAT). Comparisons between the amino acid sequences of the pSCS7-encoded CAT from S. aureus and the previously sequenced CAT variants from S. aureus, Staphylococcus intermedius, Staphylococcus haemolyticus, Bacillus pumilis, Clostridium difficile, Clostridium perfringens, Escherichia coli, Shigella flexneri, and Proteus mirabilis were performed. An alignment of CAT amino acid sequences demonstrated the presence of 34 conserved amino acids among all CAT variants. These conserved residues were considered for their possible roles in the structure and function of CAT. On the basis of the alignment, a phylogenetic tree was constructed. It demonstrated relatively large evolutionary distances between the CAT variants of enteric bacteria, Clostridium, Bacillus, and Staphylococcus species.

  8. Chloramphenicol binding to human serum albumin: Determination of binding constants and binding sites by steady-state fluorescence

    NASA Astrophysics Data System (ADS)

    Ding, Fei; Zhao, Guangyu; Chen, Shoucong; Liu, Feng; Sun, Ying; Zhang, Li

    2009-07-01

    The interaction between chloramphenicol and human serum albumin (HSA) was studied by fluorescence, UV/vis, circular dichroism (CD) and three-dimensional fluorescence spectroscopy. Fluorescence data revealed that the fluorescence quenching of HSA by chloramphenicol was the result of the formation of drug-HSA complex, and the effective quenching constants ( Ka) were 2.852 × 10 4, 2.765 × 10 4, 2.638 × 10 4 and 2.542 × 10 4 M -1 at 287, 295, 303 and 311 K, respectively. The thermodynamic parameters, enthalpy change (Δ H) and entropy change (Δ S) for the reaction were calculated to be -3.634 kJ mol -1 and 72.66 J mol -1 K -1 according to van't Hoff equation. The results indicated that the hydrophobic and electrostatic interactions played a major role in the binding of drug to HSA. The distance r between donor and acceptor was obtained to be 3.63 nm according to Förster's theory. Site marker competitive experiments indicated that the binding of drug to HSA primarily took place in subdomain IIA. The alterations of HSA secondary structure in the presence of chloramphenicol were confirmed by the evidences from synchronous fluorescence, CD and three-dimensional fluorescence spectra. In addition, the effect of common ions on the binding constants of drug-HSA complex was also discussed.

  9. Changing antibiotic sensitivity pattern and scope of chloramphenicol in the management of hospitalised patients of typhoid fever.

    PubMed

    Beig, Farzana K; Ahmad, Farida; Abqari, Shaad

    2009-12-01

    Enteric fever is a global health problem and there is emerging drug resistance with some reports of re-emerging sensitivity to previously used antibiotics eg, chloramphenicol. This study was done to compare the drug sensitivity pattern of enteric fever over a decade period. Twenty-five culture positive patients for S typhi from one study done between October 1993 to February 1995 and 35 positive patients from another study done between September 2005 and August 2006 in the same hospital were taken into account and their sensitivity pattern was compared. A total of 36% of cases were sensitive to all the drugs and equal number were multidrug resistant in the study in 1995, while in 2006 only 14.2% (p<0.05) were sensitive to all drugs and percentage of multidrug resistance has increased to 42% (p>0.05). Sensitivity to chloramphenicol had decreased from 68.00% to 54.30% (p>0.05). With the emergence of resistant strains there is significant decline in overall sensitivity to all first line drugs. However there is no change in chloramphenicol sensitivity of Salmonella enterica serovar typhi 10 years back and now, this alone is not the sufficient reason for reintroduction of this drug especially in younger patients.

  10. In vitro susceptibility of 104 clinical isolates of Haemophilus influenzae to moxalactam (LY127935), ampicillin, chloramphenicol, and ticarcillin.

    PubMed Central

    Mason, E O; Kaplan, S L; Anderson, D C; Hinds, D B; Feigin, R D

    1980-01-01

    A total of 104 strains of Haemophilus influenzae isolated from pediatric patients over a 1-year period were tested for susceptibility to moxalactam (LY127935), ampicillin, chloramphenicol, and ticarcillin. Of these strains, 30 produced beta-lactamase. LY127935 inhibited 99% of the strains at a concentration of 0.125 microgram/ml; the remaining strain was inhibited by this antibiotic at 0.25 microgram/ml. beta-Lactamase-producing strains were inhibited by ampicillin at greater than or equal to 2 microgram/ml. beta-Lactamase-negative strains were all inhibited by ampicillin at less than or equal to 1 microgram/ml, except for one nontypable strain which required 2 microgram of ampicillin per ml for inhibition. All strains were susceptible to chloramphenicol at less than or equal to 4 microgram/ml. beta-Lactamase-producing strains were less susceptible (geometric mean = 4.702 microgram/ml) to ticarcillin than were strains which did not produce beta-lactamase (geometric mean = 0.331 microgram/ml). LY127935 susceptibility was not influenced by increasing inoculum size, as ws ampicillin susceptibility. Combinations of LY127935 and chloramphenicol or ampicillin were not antagonistic in vitro. PMID:6448579

  11. Single-disk diffusion testing (Kirby-Bauer) of susceptibility of Proteus mirabilis to chloramphenicol: significance of the intermediate category.

    PubMed

    Furtado, G L; Medeiros, A A

    1980-10-01

    The significance of the intermediate category of the single-disk diffusion test (Kirby-Bauer) of antibiotic susceptibility has never been clearly defined. Thirty-two percent of 756 clinical isolates of Proteus mirabilis were of intermediate susceptibility to chloramphenicol, a higher percentage than for any other species. The breakpoint separating susceptible and intermediate isolates nearly bisected the frequency distribution of zone diameters of P. mirabilis but not that of the other species. The breakpoint separating susceptible and intermediate isolates nearly bisected the frequency distribution of zone diameters of P. mirabillis but not that of the other species tested. By serial broth dilution testing, the minimal inhibitory concentrations (MICs) of chloramphenicol of 50 individual isolates of P. mirabilis were 3.9 to 22.1 micrograms/ml (geometric mean, 8.0), whereas the MICs of susceptible Escherichia coli, Klebsiella, and Enterobacter strains were 2.0 to 3.9 micrograms/ml (geometric mean, 2.9). Seventy percent of isolates of P. mirabilis with MICs of 7.8 to 15.6 micrograms/ml were classified as susceptible by disk testing. We conclude that existing Kirby-Bauer breakpoints do not accurately discriminate P. mirabilis isolates that are marginally susceptible to chloramphenicol. These data underscore the difficulty of applying a single set of breakpoints to all species and suggest that species-specific breakpoints would more accurately predict the MIC equivalent of given zone diameters.

  12. The plasmid-encoded chloramphenicol-resistance protein of Rhodococcus fascians is homologous to the transmembrane tetracycline efflux proteins.

    PubMed

    Desomer, J; Vereecke, D; Crespi, M; Van Montagu, M

    1992-08-01

    The nucleotide sequence of the chloramphenicol-resistance gene (cmr) of Rhodococcus fascians NCPPB 1675 (located on the conjugative plasmid pRF2) allowed the identification of two possible open reading frames (ORFs), of which ORF1 was consistent with the mutational analysis. Biochemical analysis of cmr revealed that it does not encode an antibiotic-modifying enzyme. The amino acid sequence of ORF1 predicted a hydrophobic protein, with 12 putative membrane-spanning domains, homologous to proteins involved in the efflux of tetracycline across the plasma membrane. Expression of the cmr gene was induced by addition of chloramphenicol to the growth media. The promoter of this gene was restricted to 50 bp upstream from a 200 bp 5'-untranslated mRNA region, the latter containing two inverted repeats. At the amino acid level, the cmr gene is 52% identical to a previously identified chloramphenicol-resistance determinant in Streptomyces lividans, indicating a wider dispersion of this type of cmr gene among the actinomycetes.

  13. Molecular characterizations of chloramphenicol- and oxytetracycline-resistant bacteria and resistance genes in mariculture waters of China.

    PubMed

    Dang, Hongyue; Zhao, Jingyi; Song, Linsheng; Chen, Mingna; Chang, Yaqing

    2009-07-01

    In order to gain an understanding of the diversity and distribution of antimicrobial-resistant bacteria and their resistance genes in maricultural environments, multidrug-resistant bacteria were screened for the rearing waters from a mariculture farm of China. Both abalone Haliotis discushannai and turbot Scophthalmus maximus rearing waters were populated with abundant chloramphenicol-resistant bacteria. These bacteria were also multidrug resistant, with Vibriosplendidus and Vibriotasmaniensis being the most predominant species. The chloramphenicol-resistance gene cat II, cat IV or floR could be detected in most of the multidrug-resistant isolates, and the oxytetracycline-resistance gene tet(B), tet(D), tet(E) or tet(M) could also be detected for most of the isolates. Coexistence of chloramphenicol- and oxytetracycline-resistance genes partially explains the molecular mechanism of multidrug resistance in the studied maricultural environments. Comparative studies with different antimicrobial agents as the starting isolation reagents may help detect a wider diversity of the antimicrobial-resistant bacteria and their resistance genes.

  14. Adsorption behavior and mechanism of chloramphenicols, sulfonamides, and non-antibiotic pharmaceuticals on multi-walled carbon nanotubes.

    PubMed

    Zhao, Heng; Liu, Xue; Cao, Zhen; Zhan, Yi; Shi, Xiaodong; Yang, Yi; Zhou, Junliang; Xu, Jiang

    2016-06-05

    The adsorption behavior of different emerging contaminants (3 chloramphenicols, 7 sulfonamides, and 3 non-antibiotic pharmaceuticals) on five types of multi-walled carbon nanotubes (MWCNTs), and the underlying factors were studied. Adsorption equilibriums were reached within 12h for all compounds, and well fitted by the Freundlich isotherm model. The adsorption affinity of pharmaceuticals was positively related to the specific surface area of MWCNTs. The solution pH was an important parameter of pharmaceutical adsorption on MWCNTs, due to its impacts on the chemical speciation of pharmaceuticals and the surface electrical property of MWCNTs. The adsorption of ionizable pharmaceuticals decreased in varying degrees with the increased ionic strength. MWCNT-10 was found to be the strongest adsorbent in this study, and the Freundlich constant (KF) values were 353-2814mmol(1-n)L(n)/kg, 571-618mmol(1-n)L(n)/kg, and 317-1522mmol(1-n)L(n)/kg for sulfonamides, chloramphenicols, and non-antibiotic pharmaceuticals, respectively. The different adsorption affinity of sulfonamides might contribute to the different hydrophobic of heterocyclic substituents, while chloramphenicols adsorption was affected by the charge distribution in aromatic rings via substituent effects.

  15. Could chloramphenicol be used against ESKAPE pathogens? A review of in vitro data in the literature from the 21st century.

    PubMed

    Čivljak, Rok; Giannella, Maddalena; Di Bella, Stefano; Petrosillo, Nicola

    2014-02-01

    The widespread use of antibiotics has been associated with the emergence of antimicrobial resistance among bacteria. 'ESKAPE' (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acintobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) pathogens play a major role in the rapidly changing scenario of antimicrobial resistance in the 21st century. Chloramphenicol is a broad spectrum antibiotic that was abandoned in developed countries due to its association with fatal aplastic anemia. However, it is still widely used in the developing world. In light of the emerging problem of multi-drug resistant pathogens, its role should be reassessed. Our paper reviews in vitro data on the activity of chloramphenicol against ESKAPE pathogens. Susceptibility patterns for Gram-positives were good, although less favorable for Gram-negatives. However, in combination with colistin, chloramphenicol was found to have synergistic activity. The risk-benefit related to chloramphenicol toxicity has not been analyzed. Therefore, extra precautions should be taken when prescribing this agent.

  16. An investigation of prescription and over-the-counter supply of ophthalmic chloramphenicol in Wales in the 5 years following reclassification.

    PubMed

    Du, Hank C T; John, Dai N; Walker, Roger

    2014-02-01

    The aims of the study were to (i) quantify the sales of over-the-counter (OTC) ophthalmic chloramphenicol from all community pharmacies in Wales and investigate the impact on primary care prescriptions up to 5 years after reclassification and (ii) investigate the temporal relationship between items supplied OTC and on NHS primary care prescriptions. Primary care prescription data (2004-2010) and OTC sales data (2005-2010) for ophthalmic chloramphenicol were obtained. The quantity sold OTC was calculated from pharmacy wholesale records and sales data from a large pharmacy multiple. Spearman's rank correlation for prescription and OTC supplies of ophthalmic chloramphenicol was calculated for data from January 2008 to December 2010. OTC supply of chloramphenicol eye drops and ointment were both highest in 2007-2008 and represented 68% (57,708/84,304) and 48% (22,875/47,192) of the corresponding prescription volume, respectively. There was a steady year-on-year increase in the combined supply of OTC ophthalmic chloramphenicol and that dispensed on prescription from 144,367 items in 2004-2005 to 210,589 in 2007-2008 before stabilising in 2008-2009 and 2009-2010. A significant positive correlation was observed between prescription items and OTC sales of chloramphenicol eye drops and ointment combined (r=0.7, P<0.001). OTC availability increased the total quantity of ophthalmic chloramphenicol supplied in primary care compared to that seen prior to reclassification. Although growth in the sales of ophthalmic chloramphenicol OTC has stabilised and the supply pattern mirrors primary care prescribers, further work is required to investigate whether use is appropriate and whether the publication of updated practice guidance has changed this. © 2013 The Authors. IJPP © 2013 Royal Pharmaceutical Society.

  17. Improvement of chloramphenicol production in Streptomyces venezuelae ATCC 10712 by overexpression of the aroB and aroK genes catalysing steps in the shikimate pathway.

    PubMed

    Vitayakritsirikul, Vipawan; Jaemsaeng, Ratchaniwan; Lohmaneeratana, Karan; Thanapipatsiri, Anyarat; Daduang, Ratama; Chuawong, Pitak; Thamchaipenet, Arinthip

    2016-03-01

    Streptomyces venezuelae ATCC 10712 produces chloramphenicol in small amounts. To enhance chloramphenicol production, two genes, aroB and aroK, encoding rate-limiting enzymes of the shikimate pathway were overexpressed using the expression vector pIJ86 under the control of the strong constitutive ermE* promoter. The recombinant strains, S. venezuelae/pIJ86-aroB and S. venezuelae/pIJ86-aroK, produced 2.5- and 4.3-fold greater amounts respectively of chloramphenicol than wild type at early stationary phase of growth. High transcriptional levels of aroB and aroK genes were detected at the early exponential growth of both recombinant strains and consistent with the enhanced expression of pabB gene encoding an early enzyme in chloramphenicol biosynthesis. The results suggested that the increment of carbon flux was directed towards intermediates in the shikimate pathway required for the production of chorismic acid, and consequently resulted in the enhancement of chloramphenicol production. This work is the first report of a convenient genetic approach to manipulate primary metabolite genes in S. venezuelae in order to increase chloramphenicol production.

  18. Flow-injection chemiluminescence method for the determination of chloramphenicol based on luminol-sodium periodate order-transform second-chemiluminescence reaction.

    PubMed

    Zhuang, Ya-Feng; Zhu, Sheng-Nan; Wei, Wei; Li, Jie-Li

    2011-01-01

    A new chemiluminescence (CL) reaction was observed when chloramphenicol solution was injected into the mixture after the end of the reaction of alkaline luminol and sodium periodate or sodium periodate was injected into the reaction mixture of chloramphenicol and alkaline luminol. This reaction is described as an order-transform second-chemiluminescence (OTSCL) reaction. The OTSCL method combined with a flow-injection technique was applied to the determination of chloramphenicol. The optimum conditions for the order-transform second-chemiluminescence emission were investigated. A mechanism for OTSCL has been proposed on the basis of the chemiluminescence kinetic characteristics, the UV-visible spectra and the chemiluminescent spectra. Under optimal experimental conditions, the CL response is proportional to the concentration of chloramphenicol over the range 5.0 × 10(-7)-5.0 × 10(-5) mol/L with a correlation coefficient of 0.9969 and a detection limit of 6.0 × 10(-8) mol/L (3σ). The relative standard deviation (RSD) for 11 repeated determinations of 5.0 × 10(-6) mol/L chloramphenicol is 1.7%. The method has been applied to the determination of chloramphenicol in pharmaceutical samples with satisfactory results.

  19. Bacteria isolated from sewage influent resistant to ciprofloxacin, chloramphenicol and tetracycline.

    PubMed

    Zwenger, Sam R; Gillock, Eric T

    2009-02-01

    This study assessed the presence of antibiotic-resistant bacteria in sewage influent. Resistance was measured by determining the lowest concentration of antibiotic, in micrograms per milliliter (microg mL(- 1)). To determine the minimum inhibitory concentration (MIC), which is used in diagnostic laboratories, we used the Etest, a plastic strip containing an antibiotic concentration gradient. In total, we sampled five sewage treatment plants of various sizes in Kansas and isolated bacteria resistant to three broad-spectrum antibiotics; ciprofloxacin (1-cyclopropyl-6-fluoro-4-oxo-7-piperazin-1-yl-quinoline-3-carboxylic acid), chloramphenicol 2,2-dichlor-N-[(aR, bR)-b-hydroxy-a-hydroxymethyl-4-nitrophenethyl] acetamide), and tetracycline (2-(amino-hydroxy-ethylidene)-4-dimethylamino-6,10,11,12a-tetrahydroxy-6-methyl-4,4a,5,5a-tetrahydrotetracene-1,3,12-trione). In total, 25 Gram-negative isolates were found to be resistant to at least one of the antibiotics tested. Some isolates were multi-drug resistant, regardless of the amount of influent the sewage treatment plant received. A Pseudomonas isolate from the smallest sewage treatment plant (approximately 2 million gallons treated per day) showed resistance to all three antibiotics, albeit at low levels (10 microg mL(- 1)). The largest number of bacteria (6 species) were isolated from the largest sewage treatment plant (45 million gallons per day). Regardless, the results of this study are in agreement with similar studies, antibiotic resistance can persist long after the antibiotics have been forgotten.

  20. Determination of Aflatoxin M1 and Chloramphenicol in Milk Based on Background Fluorescence Quenching Immunochromatographic Assay

    PubMed Central

    Wu, Xiaoxia; Tian, Xiaofeng; Xu, Lihua; Li, Jiutong

    2017-01-01

    Harsh demanding has been exposed on the concentration of aflatoxin M1 (AFM1) and chloramphenicol (CAP) in milk. In this study, we developed a new method based on background fluorescence quenching immunochromatographic assay (bFQICA) to detect AFM1 and CAP in milk. The detection limit for AFM1 was 0.0009 ng/mL, while that for the CAP was 0.0008 ng/mL. The assay variability was determined with 3 AFM1 standards (i.e., 0.25 ng/mL, 0.5 ng/mL, and 1.0 ng/mL), and the actual detection value was 0.2497, 0.5329, and 1.0941, respectively. For the assay variability of 3 CAP standards (i.e., 0.10 ng/mL, 0.30 ng/mL, and 0.50 ng/mL), the actual detection value was 0.0996, 0.3096, and 0.4905, respectively. The recovery rate of AFM1 was 99.7%–101.7%, while that for CAP was 95.3%–97.6%. For the test stability, AFM1 and CAP showed satisfactory test stability even at month 5. Compared with the sensitivity of liquid chromatography-mass spectrometry (LC-MS) method, no statistical difference was noticed in results of the bFQICA. Our method is convenient for the detection of AFM1 and CAP in milk with a test duration of about 8 minutes. Additionally, an internal WiFi facility is provided in the system allowing for quick connection and storage in the intelligent cell phone. PMID:28367449

  1. Assessment of commutability for candidate certified reference material ERM-BB130 "chloramphenicol in pork".

    PubMed

    Zeleny, Reinhard; Emteborg, Håkan; Schimmel, Heinz

    2010-10-01

    Chloramphenicol (CAP), an effective antibiotic against many microorganisms, is meanwhile banned in the EU for treatment of food-producing animals due to adverse health effects. The Institute for Reference Materials and Measurements (IRMM) is currently developing a certified reference material (CRM) for CAP in pork, intended for validation and method performance verifications of analytical methods. The material will be certified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) methods and has a target CAP level around the minimum required performance limit (MRPL) of 0.3 microg/kg. To prove that the material can be applied as a quality control tool for screening methods, a commutability study was conducted, involving five commercially available enzyme-linked immunosorbent assay kits and one biosensor assay (BiaCore kit). Meat homogenates (cryo-milled wet tissue) with CAP concentrations around the MRPL and the candidate CRM (lyophilised powder) were measured by LC-MS/MS and GC-MS as well as the six screening methods. Pairwise method comparisons of results obtained for the two sample types showed that the CRM can successfully be applied as quality control (QC) sample to all six screening methods. The study suggests that ERM-BB130 is sufficiently commutable with the investigated assays and that laboratories applying one of the investigated kits therefore benefit from using ERM-BB130 to demonstrate the correctness of their results. However, differences among the assays were observed, either in the abundance of bias between screening and confirmatory LC and GC methods, the repeatability of test results, or goodness of fit between the methods.

  2. A competitive immunoassay for sensitive detection of small molecules chloramphenicol based on luminol functionalized silver nanoprobe.

    PubMed

    Yu, Xiuxia; He, Yi; Jiang, Jie; Cui, Hua

    2014-02-17

    Chloramphenicol (CHL) as a broad-spectrum antibiotic has a broad action spectrum against Gram-positive and Gram-negative bacteria, as well as anaerobes. The use of CHL is strictly restricted in poultry because of its toxic effect. However, CHL is still illegally used in animal farming because of its accessibility and low cost. Therefore, sensitive methods are highly desired for the determination of CHL in foodstuffs. The immunoassays based on labeling as an important tool have been reported for the detection of CHL residues in food-producing animals. However, most of the labeling procedures require multi-step reactions and purifications and thus they are complicated and time-consuming. Recently, in our previous work, luminol functionalized silver nanoparticles have been successfully synthesized, which exhibits higher CL efficiency than luminol functionalized gold nanoparticles. In this work, the new luminol functionalized silver nanoparticles have been used for the labeling of small molecules CHL for the first time and a competitive chemiluminescent immunoassay has been developed for the detection of CHL. Owing to the amplification of silver nanoparticles, high sensitivity for CHL could be achieved with a low detection limit of 7.6×10(-9) g mL(-1) and a wide linear dynamic range of 1.0×10(-8)-1.0×10(-6) g mL(-1). This method has also been successfully applied to determine CHL in milk and honey samples with a good recoveries (92% and 102%, 99% and 107% respectively), indicating that the method is feasible for the determination of CHL in real milk and honey samples. The labeling procedure is simple, convenient and fast, superior to previously reported labeling procedures. The immunoassay is also simple, fast, sensitive and selective. It is of application potential for the determination of CHL in foodstuffs. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Radiation sensitivity of Salmonella isolates relative to resistance to ampicillin, chloramphenicol or gentamicin

    NASA Astrophysics Data System (ADS)

    Niemira, Brendan A.; Lonczynski, Kelly A.; Sommers, Christopher H.

    2006-09-01

    Antibiotic resistance of inoculated bacteria is a commonly used selective marker. Bacteria resistant to the antibiotic nalidixic acid have been shown to have an increased sensitivity to irradiation. The purpose of this research was to screen a collection of Salmonella isolates for antibiotic resistance and determine the association, if any, of antibiotic resistance with radiation sensitivity. Twenty-four clinical isolates of Salmonella were screened for native resistance to multiple concentrations of ampicillin (Amp), chloramphenicol (Chl), or gentamicin (Gm). Test concentrations were chosen based on established clinical minimum inhibitory concentration (MIC) levels, and isolates were classified as either sensitive or resistant based on their ability to grow at or above the MIC. Salmonella cultures were grown overnight at (37 °C) in antibiotic-amended tryptic soy broth (TSB). Native resistance to Gm was observed with each of the 24 isolates (100%). Eight isolates (33%) were shown to be resistant to Amp, while seven isolates (29%) were shown to be resistant to Chl. In separate experiments, Salmonella cultures were grown overnight (37 °C) in TSB, centrifuged, and the cell pellets were re-suspended in phosphate buffer. The samples were then gamma irradiated at doses up to 1.0 kGy. The D10 values (the ionizing radiation dose required to reduce the viable number of microorganisms by 90%) were determined for the 24 isolates and they ranged from 0.181 to 0.359 kGy. No correlation was found between the D10 value of the isolate and its sensitivity or resistance to each of the three antibiotics. Resistance to Amp or Chl is suggested as appropriate resistance marker for Salmonella test strains to be used in studies of irradiation.

  4. Zero valent iron produces dichloroacetamide from chloramphenicol antibiotics in the absence of chlorine and chloramines.

    PubMed

    Chu, Wenhai; Ding, Shunke; Bond, Tom; Gao, Naiyun; Yin, Daqiang; Xu, Bin; Cao, Zhongqi

    2016-11-01

    Dichloroacetamide (DCAcAm) is an important type of nitrogenous disinfection byproduct. This study is the first to report that DCAcAm can be formed in the absence of chlorinated disinfectants (chlorine and chloramines). This can occur through reduction of three chloramphenicol (CAP) antibiotics by zero valent iron (ZVI). The effects of key experimental parameters, including reaction time, ZVI dose, pH, temperature, water type, and the presence of humic acid (HA) on the formation of DCAcAm were ascertained. The DCAcAm yields from three CAPs all presented the trend of increasing first and then decreasing with time and also increased with increasing ZVI dosage. DCAcAm yields from the ZVI reduction route were higher than those resulting from the chlorination of some previously identified DCAcAm precursors. Acidic conditions favored the formation of DCAcAm by the ZVI route. In addition, lower temperatures increased DCAcAm yields at extended contact times (>12 h). DCAcAm formed from the three CAPs in the presence of HA was lower than in the absence of HA. The formation potential of DCAcAm from the reduction of authentic waters spiked with CAPs by ZVI showed good linear correlations with initial concentrations of the three CAPs. This allows the formation of DCAcAm from the reduction of CAPs by ZVI to be predicted. Given that many wastewater and drinking water distribution networks contain unlined cast iron pipes, reactions between CAPs and ZVI may contribute to the formation of DCAcAm in such systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Determination of chloramphenicol residues in commercial chicken eggs in the Federal Capital Territory, Abuja, Nigeria.

    PubMed

    Mbodi, Felix E; Nguku, P; Okolocha, E; Kabir, J

    2014-01-01

    The use of antibiotics in poultry can result in residues in eggs. The joint FAO/WHO committee recommended banning the use of chloramphenicol (CAP) in food animals due to its public health hazards of aplastic anaemia, leukaemia, allergy, antibacterial resistance and carcinogenicity. This paper determines the prevalence of CAP residues in chicken eggs and assesses the usage and awareness of its ban amongst poultry farmers in the Federal Capital Territory (FCT), Abuja, Nigeria. A cross-sectional survey of registered poultry farmers in FCT was conducted using questionnaires to determine CAP administration in poultry and awareness of its ban. Pooled egg samples were collected from each poultry farm surveyed and from randomly sampled government-owned markets in FCT. Source of eggs by state were identified by the marketer at the time of collection. Samples were analysed using an enzyme-linked immunosorbent assay (ELISA) technique for the presence of CAP, and prevalence was determined. Of 288 total pooled samples collected, 257 (89.2%) were from the markets and 31 (10.8%) were from poultry farms. A total of 20 (7%) pooled egg samples tested CAP-positive; market eggs originated from 15 (41%) states of the country. Of the market eggs, 16 (6.2%) pooled samples tested positive. Of eggs from poultry farms, four (12.9%) tested positive. Mean CAP concentrations in the positive samples ranged from 0.49 to 1.17 µg kg(-1) (parts per billion). CAP use amongst poultry farmers in FCT was 75.5%; awareness of the CAP ban was 26.3%. Though 66% of veterinarians were unaware of a CAP ban, they were more likely to be aware than other poultry farmers (odds ratio (OR) = 1.4). Farm managers who use CAP were more likely to be aware of CAP ban than the farm managers not using CAP (OR = 5.5; p = 0.04). Establishing a drug residue surveillance and control program and enforcement of CAP legislation/regulation is needful to educate and prohibit the widespread CAP use amongst Nigerian poultry farmers.

  6. Biosynthesis of the dichloroacetyl component of chloramphenicol in Streptomyces venezuelae ISP5230: genes required for halogenation.

    PubMed

    Piraee, Mahmood; White, Robert L; Vining, Leo C

    2004-01-01

    Five ORFs were detected in a fragment from the Streptomyces venezuelae ISP5230 genomic DNA library by hybridization with a PCR product amplified from primers representing a consensus of known halogenase sequences. Sequencing and functional analyses demonstrated that ORFs 11 and 12 (but not ORFs 13-15) extended the partially characterized gene cluster for chloramphenicol (Cm) biosynthesis in the chromosome. Disruption of ORF11 (cmlK) or ORF12 (cmlS) and conjugal transfer of the insertionally inactivated genes to S. venezuelae gave mutant strains VS1111 and VS1112, each producing a similar series of Cm analogues in which unhalogenated acyl groups replaced the dichloroacetyl substituent of Cm. 1H-NMR established that the principal metabolite in the disrupted strains was the alpha-N-propionyl analogue. The sequence of CmlK implicated the protein in adenylation, and involvement in halogenation was inferred from biosynthesis of analogues by the cmlK-disrupted mutant. A role in generating the dichloroacetyl substituent was supported by partial restoration of Cm biosynthesis when a cloned copy of cmlK was introduced in trans into VS1111. Complementation of the mutant also indicated that inactivation of cmlK rather than a polar effect of the disruption on cmlS expression had interfered with dichloroacetyl biosynthesis. The deduced CmlS sequence resembled sequences of FADH2-dependent halogenases. Conjugal transfer of cmlK or cmlS into S. venezuelae cml-2, a chlorination-deficient strain with a mutation mapped genetically to the Cm biosynthesis gene cluster, did not complement the cml-2 lesion, suggesting that one or more genes in addition to cmlK and cmlS is needed to assemble the dichloroacetyl substituent. Insertional inactivation of ORF13 did not affect Cm production, and the products of ORF14 and ORF15 matched Streptomyces coelicolor A3(2) proteins lacking plausible functions in Cm biosynthesis. Thus cmlS appears to mark the downstream end of the gene cluster.

  7. Salmonella typhi resistant to Chloramphenicol, Ampicillin, and Other Antimicrobial Agents: Strains Isolated During an Extensive Typhoid Fever Epidemic in Mexico

    PubMed Central

    Olarte, Jorge; Galindo, Emma

    1973-01-01

    During 1972 a large epidemic, in excess of 10,000 cases, of typhoid fever occurred in Mexico City, Pachuca, and other communities of Mexico. The main characteristic of the epidemic, in addition to the large number of persons affected, was the prevalence of a strain of Salmonella typhi which was highly resistant to chloramphenicol both in vivo and in vitro, and which belonged to a single phage type, Vi degraded approaching type A. Of 493 strains of S. typhi studied during the outbreak, 452 (91.7%) were resistant to chloramphenicol (CM), tetracycline (TC), streptomycin (SM), and sulfonamides (SU). The epidemic strain owes its resistance to an R factor which is easily transferable to Escherichia coli K-12 and which appears to be stable. In the third month of the outbreak, a strain of S. typhi resistant to CM, TC, SM, SU, ampicillin (AM), and kanamycin (KM) was isolated from a patient with severe typhoid fever. During the following 9 months, six additional strains of S. typhi resistant to AM, CM, TC, SM, and SU were also isolated. Transfer experiments to E. coli K-12 indicate that these strains are infected with two different R factors, one causing CM, TC, SM, and SU resistance and the other causing AM or AM and KM resistance. The frequency of transfer of the resistance in overnight crosses was in the order of 10−4 for CM, TC, SM, and SU and 10−6 for AM or AM, and KM. The appearance of these strains resistant both to chloramphenicol and ampicillin was a cause for concern for the clinicians; fortunately, they have remained an infrequent cause of disease. PMID:4602828

  8. Chloramphenicol Biosynthesis: The Structure of CmlS, a Flavin-Dependent Halogenase Shwing a Covalent Flavin-Aspartate Bond

    SciTech Connect

    Podzelinska, K.; Latimer, R; Bhattacharya, A; Vining, L; Zechel, D; Jia, Z

    2010-01-01

    Chloramphenicol is a halogenated natural product bearing an unusual dichloroacetyl moiety that is critical for its antibiotic activity. The operon for chloramphenicol biosynthesis in Streptomyces venezuelae encodes the chloramphenicol halogenase CmlS, which belongs to the large and diverse family of flavin-dependent halogenases (FDH's). CmlS was previously shown to be essential for the formation of the dichloroacetyl group. Here we report the X-ray crystal structure of CmlS determined at 2.2 {angstrom} resolution, revealing a flavin monooxygenase domain shared by all FDHs, but also a unique 'winged-helix' C-terminal domain that creates a T-shaped tunnel leading to the halogenation active site. Intriguingly, the C-terminal tail of this domain blocks access to the halogenation active site, suggesting a structurally dynamic role during catalysis. The halogenation active site is notably nonpolar and shares nearly identical residues with Chondromyces crocatus tyrosyl halogenase (CndH), including the conserved Lys (K71) that forms the reactive chloramine intermediate. The exception is Y350, which could be used to stabilize enolate formation during substrate halogenation. The strictly conserved residue E44, located near the isoalloxazine ring of the bound flavin adenine dinucleotide (FAD) cofactor, is optimally positioned to function as a remote general acid, through a water-mediated proton relay, which could accelerate the reaction of the chloramine intermediate during substrate halogenation, or the oxidation of chloride by the FAD(C4{alpha})-OOH intermediate. Strikingly, the 8{alpha} carbon of the FAD cofactor is observed to be covalently attached to D277 of CmlS, a residue that is highly conserved in the FDH family. In addition to representing a new type of flavin modification, this has intriguing implications for the mechanism of FDHs. Based on the crystal structure and in analogy to known halogenases, we propose a reaction mechanism for CmlS.

  9. Inhibition of Escherichia coli ribosome subunit dissociation by chloramphenicol and Blasticidin: a new mode of action of the antibiotics.

    PubMed

    Pathak, B K; Mondal, S; Barat, C

    2017-01-01

    The ability of the ribosome to assist in folding of proteins both in vitro and in vivo is well documented and is a nontranslational function of the ribosome. The interaction of the unfolded protein with the peptidyl transferase centre (PTC) of the bacterial large ribosomal subunit is followed by release of the protein in the folding competent state and rapid dissociation of ribosomal subunits. Our study demonstrates that the PTC-specific antibiotics, chloramphenicol and blasticidin S inhibit unfolded protein-mediated subunit dissociation. During post-termination stage of translation in bacteria, ribosome recycling factor (RRF) is used together with elongation factor G to recycle the 30S and 50S ribosomal subunits for the next round of translation. Ribosome dissociation mediated by RRF and induced at low magnesium concentration was also inhibited by the antibiotics indicating that the PTC antibiotics exert an associative effect on ribosomal subunits. In vivo, the antibiotics can also reduce the ribosomal degradation during carbon starvation, a process requiring ribosome subunit dissociation. This study reveals a new mode of action of the broad-spectrum antibiotics chloramphenicol and blasticidin. Ribosome synthesizes protein in all organisms and is the target for multiple antimicrobial agents. Our study demonstrates that chloramphenicol and blasticidin S that target the peptidyl transferase centre of the bacterial ribosome can then inhibit dissociation of 70S ribosome mediated by (i) unfolded protein, (ii) translation factors or (iii) low Mg(+2) concentrations in vitro and thereby suppresses ribosomal degradation during carbon starvation in vivo. The demonstration of this new mode of action furthers the understanding of these broad-spectrum antibiotics that differentially inhibit protein synthesis in prokaryotic and eukaryotic cells. © 2016 The Society for Applied Microbiology.

  10. Determination of chloramphenicol residue in fish and shrimp tissues by gas chromatography with a microcell electron capture detector.

    PubMed

    Ding, Shuangyang; Shen, Jianzhong; Zhang, Suxia; Jiang, Haiyang; Sun, Zhiwen

    2005-01-01

    A gas chromatography method with microcell electron capture detection was developed for the determination of chloramphenicol residue in fish and shrimp muscle tissues. The tissue samples were extracted with ethyl acetate, defatted with hexane, and derivatized with Sylon BFT [N,O-bis (trimethylsilyl) trifluoroacetamide-trimethylchlorosilane (99 + 1)]. The limit of detection was 0.04 ng/g and the limit of quantitation 0.1 ng/g. Average recoveries were 70.8-90.8% for fish and 69.9-86.3% for shrimp, respectively. The method was validated for the determination of practical samples.

  11. Protein Synthesis by Isolated Etioplasts and Chloroplasts from Pea and Wheat and the Effects of Chloramphenicol and Cycloheximide 1

    PubMed Central

    Reger, Bonnie J.; Smillie, R. M.; Fuller, R. C.

    1972-01-01

    Etioplasts capable of incorporating 14C-leucine into protein have been isolated from dark-grown pea and wheat plants. The requirements for leucine incorporation for etioplasts were similar to those for chloroplasts. An ATP-generating system, Mg2+, and GTP were required. The amino-acid-incorporation activity of etioplasts from wheat was comparable to that of chloroplasts on an RNA basis, whereas the activity of pea etioplasts was about 50% of the activity of pea chloroplasts. The incorporation of leucine into protein by etioplasts and chloroplasts from pea and wheat was inhibited by chloramphenicol, and to a slight extent by cycloheximide. PMID:16658121

  12. Chloramphenicol encapsulated in poly-ε-caprolactone–pluronic composite: nanoparticles for treatment of MRSA-infected burn wounds

    PubMed Central

    Kalita, Sanjeeb; Devi, Banasmita; Kandimalla, Raghuram; Sharma, Kaustav Kalyan; Sharma, Arup; Kalita, Kasturi; Kataki, Amal Chandra; Kotoky, Jibon

    2015-01-01

    The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infection has increased precipitously over the past several decades, with far-reaching health care and societal costs. MRSA infections in the context of burn wounds lead to invasive disease that could potentially cause mortality. Chloramphenicol is a well-known broad-spectrum bacteriostatic antibiotic that has been used since 1949, but due to its hydrophobicity, poor penetration in skin, fast degradation, and toxicity, its application has been hindered. Furthermore, it has been demonstrated that old antibiotics such as chloramphenicol remained active against a large number of currently prevalent resistant bacterial isolates due to their low-level use in the past. Recently, the novel nanoparticulate drug-delivery system has been used and reported to be exceptionally useful for topical therapeutics, due to its distinctive physical characteristics such as a high surface-to-volume ratio and minuscule size. It helps to achieve better hydrophilicity, bioavailability, and controlled delivery with enhanced therapeutic index, which has resulted in decreased toxicity levels compared to the crude drug. Here, we report a novel chloramphenicol loaded with poly(ε-caprolactone) (PCL)-pluronic composite nanoparticles (CAM-PCL-P NPs), physicochemical characterizations, and its bioactivity evaluation in a MRSA-infected burn-wound animal model. CAM-PCL-P NPs could encapsulate 98.3% of the drug in the nanoparticles and release 81% of the encapsulated drug over 36 days with a time to 50% drug release of 72 hours (51%). Nanoparticle suspensions maintained the initial properties with respect to size and encapsulation efficiency, even after 6 months of storage at 4°C and 25°C, respectively (P>0.05). Significant reduction in the level of toxicity was observed for CAM-PCL-P NPs compared with that of free drug as confirmed from hemolytic activity against human blood erythrocytes and cytotoxicity assay against an MCF-7

  13. A simple sample preparation for simultaneous determination of chloramphenicol and its succinate esters in food products using high-performance liquid chromatography/high-resolution mass spectrometry.

    PubMed

    Amelin, Vasiliy; Korotkov, Anton

    2017-02-01

    A simple method is described for the determination of chloramphenicol and its succinate esters in food products. Examination of food products using high-performance liquid chromatography/high-resolution mass spectrometry showed the presence not only of chloramphenicol but also of its succinate forms. A scheme is proposed for determining chloramphenicol and its succinate esters (calculated as chloramphenicol) in meat (beef, pork, poultry), milk, liver, kidney, eggs, fish and honey. Analytes are extracted from a 1.0 g sample with 5 ml acetonitrile. It was found that using the method of standard addition and diluting the extract with water leads to the elimination of matrix effects and also eliminates errors associated with peak splitting due to the separate elution of the differing forms of the analyte. Validation results were satisfactory, with recoveries from 85% to 111% (meat, milk, liver, kidney, eggs, fish and honey) and a relative standard deviation (RSD) lower than 13% for spiked levels of 0.3, 1.0 and 5 µg kg(-)(1). The limits of detection and quantification (calculated as chloramphenicol for all forms) were 0.1 and 0.3 µg kg(-)(1), respectively. The RSD of the results of the analysis was < 10%. The duration of the analysis was less than 1 h.

  14. Synthesis, spectroscopic, thermal and anticancer studies of metal-antibiotic chelations: Ca(II), Fe(III), Pd(II) and Au(III) chloramphenicol complexes

    NASA Astrophysics Data System (ADS)

    Al-Khodir, Fatima A. I.; Refat, Moamen S.

    2016-09-01

    Four Ca(II), Fe(III), Pd(II) and Au(III) complexes of chloramphenicol drug have been synthesized and well characterized using elemental analyses, (infrared, electronic, and 1H-NMR) spectra, magnetic susceptibility measurement, and thermal analyses. Infrared spectral data show that the chloramphenicol drug coordinated to Ca(II), Pd(II) and Au(III) metal ions through two hydroxyl groups with 1:1 or 1:2 M ratios, but Fe(III) ions chelated towards chloramphenicol drug via the oxygen and nitrogen atoms of amide group with 1:2 ratio based on presence of keto↔enol form. The X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques were used to identify the nano-size particles of both iron(III) and gold(III) chloramphenicol complexes. The antimicrobial assessments of the chloramphenicol complexes were scanned and collected the results against of some kind of bacteria and fungi. The cytotoxic activity of the gold(III) complex was tested against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.

  15. Identification and modeling of a novel chloramphenicol resistance protein detected by functional metagenomics in a wetland of Lerma, Mexico.

    PubMed

    López-Pérez, Marcos; Mirete, Salvador; Jardón-Valadez, Eduardo; González-Pastor, José E

    2013-06-01

    The exploration of novel antibiotic resistance determinants in a particular environment may be limited because of the presence of uncultured microorganisms. In this work, a culture-independent approach based on functional metagenomics was applied to search for chloramphenicol resistance genes in agro-industrial wastewater in Lerma de Villada, Mexico. To this end, a metagenomic library was generated in Escherichia coli DH10B containing DNA isolated from environmental samples of the residual arsenic-enriched (10 mg/ml) effluent. One resistant clone was detected in this library and further analyzed. An open reading frame similar to a multidrug resistance protein from Aeromonas salmonicida and responsible for chloramphenicol resistance was identified, sequenced, and found to encode a member of the major facilitator superfamily (MFS). Our results also showed that the expression of this gene restored streptomycin sensitivity in E. coli DH10B cells. To gain further insight into the phenotype of this MFS family member, we developed a model of the membrane protein multiporter that, in addition, may serve as a template for developing new antibiotics.

  16. Antimicrobial susceptibility testing of pneumococci: determination of Kirby-Bauer breakpoints for penicillin G, erythromycin, clindamycin, tetracycline, chloramphenicol, and rifampin.

    PubMed

    Jacobs, M R; Mithal, Y; Robins-Browne, R M; Gaspar, M N; Koornhof, H J

    1979-08-01

    Antimicrobial susceptibility testing of pneumococci is now essential to monitor for the presence of resistance to agents such as the penicillins, macrolides, lincomycins, chloramphenicol, and tetracycline. In this study, clinical isolates of a selection of resistant South African strains were tested for antimicrobial susceptibility by minimal inhibitory concentration (MIC) determination and by a modified Kirby-Bauer disk diffusion technique, using Mueller-Hinton medium supplemented with 5% horse blood. Disk diffusion breakpoints were determined for penicillin G, erythromycin, clindamycin, tetracycline, chloramphenicol, and rifampin. Reliable results were obtained on disk diffusion for all these agents except for penicillin G. With 6-mug penicillin G disks, zones of strains with intermediate penicillin susceptibility overlapped those of sensitive and resistant strains. With 5-mug methicillin disks, clearer separation of strains based on susceptibility to penicillin G occurred. Strains with zones of <35 mm around penicillin G disks and <25 mm around methicillin disks should have penicillin G MICs determined to confirm their resistance to penicillin G. In view of the potential for pneumococci to be resistant to the agents used in this study, antimicrobial susceptibility of all clinically significant isolates should be determined.

  17. Comparison between Source-induced Dissociation and Collision-induced Dissociation of Ampicillin, Chloramphenicol, Ciprofloxacin, and Oxytetracycline via Mass Spectrometry.

    PubMed

    Lee, Seung Ha; Choi, Dal Woong

    2013-06-01

    Mass spectrometry (MS) is a very powerful instrument that can be used to analyze a wide range of materials such as proteins, peptides, DNA, drugs, and polymers. The process typically involves either chemical or electron (impact) ionization of the analyte. The resulting charged species or fragment is subsequently identified by the detector. Usually, single mass uses source-induced dissociation (SID), whereas mass/mass uses collision-induced dissociation (CID) to analyze the chemical fragmentations Each technique has its own advantages and disadvantages. While CID is most effective for the analysis of pure substances, multiple- step MS is a powerful technique to get structural data. Analysis of veterinary drugs ampicillin, chloramphenicol, ciprofloxacin, and oxytetracycline serves to highlight the slight differences between SID and CID. For example, minor differences were observed between ciprofloxacin and oxytetracycline via SID or CID. However, distinct fragmentation patterns were observed for ampicllin depending on the analysis method. Both SID and CID showed similar fragmentation spectra but different signal intensities for chloramphenicol. There are several factors that can influence the fragmentation spectra, such as the collision energy, major precursor ion, electrospray mode (positive or negative), and sample homogeneity. Therefore, one must select a fragmentation method on an empirical and case-by-case basis.

  18. Stability-Indicating HPLC Method for Simultaneous Determination of Chloramphenicol, Dexamethasone Sodium Phosphate and Tetrahydrozoline Hydrochloride in Ophthalmic Solution

    PubMed Central

    AlAani, Hashem; Alnukkary, Yasmin

    2016-01-01

    Purpose: A simple stability-indicating RP-HPLC assay method was developed and validated for quantitative determination of Chloramphenicol, Dexamethasone Sodium Phosphate and Tetrahydrozoline Hydrochloride in ophthalmic solution in the presence of 2-amino-1-(4-nitrophenyl)propane-1,3-diol, a degradation product of Chloramphenicol, and Dexamethasone, a degradation product of Dexamethasone Sodium Phosphate. Methods: Effective chromatographic separation was achieved using C18 column (250 mm, 4.6 mm i.d., 5 μm) with isocratic mobile phase consisting of acetonitrile - phosphate buffer (pH 4.0; 0.05 M) (30:70, v/v) at a flow rate of 1 mL/minute. The column temperature was maintained at 40°C and the detection wavelength was 230 nm. Results: The proposed HPLC procedure was statistically validated according to the ICH guideline, and was proved to be stability-indicating by resolution of the APIs from their forced degradation products. Conclusion: The developed method is suitable for the routine analysis as well as stability studies. PMID:27123429

  19. Rapid detection of chloramphenicol in animal products without clean-up using LC-high resolution mass spectrometry.

    PubMed

    Xu, Hong; Zhang, Jun; He, Jia; Mi, Jibo; Liu, Lishuang

    2011-10-01

    A rapid confirmatory and quantitative method using liquid chromatography-high resolution mass spectrometry (LC-HRMS) was developed to determine sub-µg/kg levels of chloramphenicol (CAP) in meat products. The sample plus deuterated chloramphenicol internal standard was homogenised, extracted with ethyl acetate, centrifuged and the supernatant evaporated to dryness. The residue was re-dissolved in methanol/5% ammonium acetate solution (20:80, v/v), defatted with hexane and directly injected into the LC-MS. Chromatographic separation was performed on a C(18) column using methanol/water (60:40, v/v) as the mobile phase. CAP was detected using selected ion monitoring of the high accurate mass of the molecular ion [M-H](-) of CAP using a LTQ-Orbitrap mass spectrometer in negative electrospray ionisation mode (ESI(-)). The limit of quantification of the method was 0.1 µg/kg using isotope internal standard. Recoveries of CAP spiked at levels of 0.1-1.0 µg/kg ranged from 73 to 99%, and the relative standard deviation ranged 3.9-8.1%.

  20. A structural study of the interaction between the Dr haemagglutinin DraE and derivatives of chloramphenicol

    PubMed Central

    Pettigrew, David M.; Roversi, Pietro; Davies, Stephen G.; Russell, Angela J.; Lea, Susan M.

    2009-01-01

    Dr adhesins are expressed on the surface of uropathogenic and diffusely adherent strains of Escherichia coli. The major adhesin subunit (DraE/AfaE) of these organelles mediates attachment of the bacterium to the surface of the host cell and possibly intracellular invasion through its recognition of the complement regulator decay-accelerating factor (DAF) and/or members of the carcinoembryonic antigen (CEA) family. The adhesin subunit of the Dr haemagglutinin, a Dr-family member, additionally binds type IV collagen and is inhibited in all its receptor interactions by the antibiotic chloram­phenicol (CLM). In this study, previous structural work is built upon by reporting the X-ray structures of DraE bound to two chloramphenicol derivatives: chloramphenicol succinate (CLS) and bromamphenicol (BRM). The CLS structure demonstrates that acylation of the 3-hydroxyl group of CLM with succinyl does not significantly perturb the mode of binding, while the BRM structure implies that the binding pocket is able to accommodate bulkier substituents on the N-­acyl group. It is concluded that modifications of the 3-­hydroxyl group would generate a potent Dr haemagglutinin inhibitor that would not cause the toxic side effects that are associated with the normal bacteriostatic activity of CLM. PMID:19465765

  1. Green synthesized gold nanoparticles decorated graphene oxide for sensitive determination of chloramphenicol in milk, powdered milk, honey and eye drops.

    PubMed

    Karthik, R; Govindasamy, Mani; Chen, Shen-Ming; Mani, Veerappan; Lou, Bih-Show; Devasenathipathy, Rajkumar; Hou, Yu-Shen; Elangovan, A

    2016-08-01

    A simple and rapid green synthesis using Bischofia javanica Blume leaves as reducing agent was developed for the preparation of gold nanoparticles (AuNPs). AuNPs decorated graphene oxide (AuNPs/GO) was prepared and employed for the sensitive amperometric determination of chloramphenicol. The green biosynthesis requires less than 40s to reduce gold salts to AuNPs. The formations of AuNPs and AuNPs/GO were evaluated by scanning electron and atomic force microscopies, UV-Visible and energy dispersive X-ray spectroscopies, X-ray diffraction studies, and electrochemical methods. AuNPs/GO composite film modified electrode was fabricated and shown excellent electrocatalytic ability towards chloramphenicol. Under optimal conditions, the amperometric sensing platform has delivered wide linear range of 1.5-2.95μM, low detection limit of 0.25μM and high sensitivity of 3.81μAμM(-1)cm(-2). The developed sensor exhibited good repeatability and reproducibility, anti-interference ability and long-term storage stability. Practical feasibility of the sensor has been demonstrated in food samples (milk, powdered milk and honey) and pharmaceutical sample (eye drops). The green synthesized AuNPs/GO composite has great potential for analysis of food samples in food safety measures. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Role of efflux pump(s) in intrinsic resistance of Pseudomonas aeruginosa: resistance to tetracycline, chloramphenicol, and norfloxacin.

    PubMed Central

    Li, X Z; Livermore, D M; Nikaido, H

    1994-01-01

    Most strains of Pseudomonas aeruginosa are significantly more resistant, even in the absence of R plasmids, to many antimicrobial agents, including beta-lactams, tetracycline, chloramphenicol, and fluoroquinolones, than most other gram-negative rods. This broad-range resistance has so far been assumed to be mainly due to the low permeability of the P. aeruginosa outer membrane. The intrinsic-resistance phenotype becomes further enhanced in "intrinsically carbenicillin-resistant" isolates, which were often assumed to produce outer membranes of even lower permeability. It has been shown, however, that this hypothesis cannot explain the beta-lactam resistance of these isolates (D.M. Livermore and K.W.M. Davy, Antimicrob. Agents Chemother. 35:916-921, 1991). In this study, we examined the uptake of tetracycline, chloramphenicol, and norfloxacin by intact cells using strains showing widely different levels of intrinsic resistance. Their accumulation and the response to the addition of a proton conductor showed that even relatively susceptible strains of P. aeruginosa actively pump out these compounds from the cell and that the efflux activity becomes much stronger in strains showing higher levels of intrinsic resistance. We conclude that the efflux mechanism(s) are likely to contribute significantly to the intrinsic resistance of P. aeruginosa isolates to tetracycline, chloramphenicol, and fluoroquinolones, as does the low permeability of the outer membrane. This conclusion is supported by the observation that the hypersusceptibility to various agents of the mutant K799/61 (W. Zimmermann, Antimicrob. Agents Chemother. 18:94-100, 1980) was apparently caused by the lack of active efflux. Although the hypersusceptibility of this mutant has hitherto been assumed to be solely due to its higher outer membrane permeability, its outer membrane was shown to have a coefficient of permeability to cephaloridine that was not significantly different from that of the parent, resistant

  3. Stimulation of chloramphenicol acetyltransferase mRNA translation by reovirus capsid polypeptide sigma 3 in cotransfected COS cells.

    PubMed Central

    Giantini, M; Shatkin, A J

    1989-01-01

    The mammalian reovirus S4 gene has been implicated in the serotype-dependent inhibition of host cell protein synthesis during viral replication in mouse L cells. To examine the effect(s) of this gene on transcription or translation or both, a DNA copy of the serotype 3 S4 gene was inserted into a eucaryotic expression vector. Cotransfection of COS cells with plasmids containing S4 and the reporter gene, chloramphenicol acetyltransferase (CAT), resulted in a marked stimulation of CAT expression, predominantly at the level of translation. The significance of these findings is discussed in relation to the double-stranded-RNA-binding activity of the S4 gene product, polypeptide sigma 3. Images PMID:2724407

  4. Simultaneous spectrophotometric-multivariate calibration determination of several components of ophthalmic solutions: phenylephrine, chloramphenicol, antipyrine, methylparaben and thimerosal.

    PubMed

    Collado, M S; Mantovani, V E; Goicoechea, H C; Olivieri, A C

    2000-08-16

    The use of multivariate spectrophotometric calibration for the simultaneous determination of several active components and excipients in ophthalmic solutions is presented. The resolution of five-component mixtures of phenylephrine, chloramphenicol, antipyrine, methylparaben and thimerosal has been accomplished by using partial least-squares (PLS-1) and a variant of the so-called hybrid linear analysis (HLA). Notwithstanding the presence of a large number of components and their high degree of spectral overlap, they have been determined simultaneously with high accuracy and precision, with no interference, rapidly and without resorting to extraction procedures using non aqueous solvents. A simple and fast method for wavelength selection in the calibration step is presented, based on the minimisation of the predicted error sum of squares (PRESS) calculated as a function of a moving spectral window.

  5. Purification and structural characterization of a novel antibacterial peptide from Bellamya bengalensis: activity against ampicillin and chloramphenicol resistant Staphylococcus epidermidis.

    PubMed

    Gauri, Samiran S; Mandal, Santi M; Pati, Bikas R; Dey, Satyahari

    2011-04-01

    Increasing tendency of clinical bacterial strains resistant to conventional antibiotics has being a great challenge to the public's health. Antimicrobial peptides, a new class of antibiotics is known to have the activity against a wide range of bacteria resistant to conventional antibiotics. An antimicrobial peptide of 1676 Da was purified from Bellamya bengalensis, a fresh water snail, using ultrafiltration and reversed phase liquid chromatography. The effect of this peptide on Staphylococcus epidermidis resistant to ampicillin and chloramphenicol was investigated; the MIC and MBC values were 8 μg/ml and 16 μg/ml, respectively. Complete sequence of the peptide was determined by tandem mass spectrometry (MS/MS). Further, peptide net charge, hydrophobicity and molecular modeling were evaluated in silico for better understanding the probable mechanisms of action. The peptide showed the specificity to bacterial membranes. Hence, this reported peptide revealed a promising candidate to contribute in the development of therapeutic agent for Staphylococcal infections.

  6. Enhanced inhibition of bacterial biofilm formation and reduced leukocyte toxicity by chloramphenicol:β-cyclodextrin:N-acetylcysteine complex.

    PubMed

    Aiassa, Virginia; Zoppi, Ariana; Becerra, M Cecilia; Albesa, Inés; Longhi, Marcela R

    2016-11-05

    The purpose of this study was to improve the physicochemical and biological properties of chloramphenicol (CP) by multicomponent complexation with β-cyclodextrin (β-CD) and N-acetylcysteine (NAC). The present work describes the ability of solid multicomponent complex (MC) to decrease biomass and cellular activity of Staphylococcus by crystal violet and XTT assay, and leukocyte toxicity, measuring the increase of reactive oxygen species by chemiluminescence, and using 123-dihydrorhodamine. In addition, MC was prepared by the freeze-drying or physical mixture methods, and then characterized by scanning electron microscopy and powder X-ray diffraction. Nuclear magnetic resonance and phase solubility studies provided information at the molecular level on the structure of the MC and its association binding constants, respectively. The results obtained allowed us to conclude that MC formation is an effective pharmaceutical strategy that can reduce CP toxicity against leukocytes, while enhancing its solubility and antibiofilm activity.

  7. Removal of chloramphenicol by macroporous adsorption resins in honey: a novel approach on reutilization of antibiotics contaminated honey.

    PubMed

    Cheng, Ni; Gao, Hui; Deng, Jianjun; Wang, Bini; Xu, Ruihan; Cao, Wei

    2012-09-01

    The effects of different steps in honey production on chloramphenicol (CAP) levels and CAP removal from honey using macroporous adsorption resins (MARs) were investigated in this study. CAP residues in honey were quantified by enzyme-linked immunosorbent assay after each processing step including preheating, filtration, vacuum concentration and pasteurization. Vacuum concentration contributes the most reduction of CAP level (9.9%). Meanwhile, 5 types of MARs (including LSI-1, LSI-2, LSI-3, LS-803, and LS-903) were used in CAP adsorption. The results showed that LS-803 resin had higher adsorption rate of 86% than other resins in removing CAP from honey, and its optimal adsorption time and temperature were 40 min and 55 °C, respectively. The treated honey could be used as feed additive or biomass energy. Therefore, it would be a novel approach to reutilization of antibiotics contaminated honey.

  8. Mass-spectral analysis of human interferon-gamma and chloramphenicol acetyltransferase I produced in two Escherichia coli strains.

    PubMed

    Vassileva-Atanassova, A; Niwa, T; Mironova, R; Ivanov, I

    2000-02-28

    Recombinant human interferon-gamma and chloramphenicol acetyltransferase I were isolated from two Escherichia coli strains, E. coli LE329 and E. coli XL1-blue and characterized by electrospray ionization mass spectrometry (ESI-MS). The ESI-MS analysis showed higher masses in comparison with the theoretically calculated for both proteins as well as unexpected molecular heterogeneity. The ESI-MS spectral patterns of the proteins depended on the host strain used and were more heterogenous for the proteins isolated from E. coli LE392. One of the proteins (human interferon-gamma obtained from E. coli XL1-blue) was further subjected to BrCN cleavage. The ESI-MS analysis of the polypeptide mixture revealed shift in the molecular mass for two peptides including the last 26 amino acids of the human interferon-gamma molecule.

  9. Chloramphenicol versus ampicillin plus gentamicin for community acquired very severe pneumonia among children aged 2-59 months in low resource settings: multicentre randomised controlled trial (SPEAR study)

    PubMed Central

    2008-01-01

    Objective To evaluate whether five days’ treatment with injectable ampicillin plus gentamicin compared with chloramphenicol reduces treatment failure in children aged 2-59 months with community acquired very severe pneumonia in low resource settings. Design Open label randomised controlled trial. Setting Inpatient wards within tertiary care hospitals in Bangladesh, Ecuador, India, Mexico, Pakistan, Yemen, and Zambia. Participants Children aged 2-59 months with WHO defined very severe pneumonia. Intervention Chloramphenicol versus a combination of ampicillin plus gentamicin. Main outcome measures Primary outcome measure was treatment failure at five days. Secondary outcomes were treatment failure defined similarly among all participants evaluated at 48 hours and at 10 and 21 days. Results More children failed treatment with chloramphenicol at day 5 (16% v 11%; relative risk 1.43, 95% confidence interval 1.03 to 1.97) and also by days 10 and 21. Overall, 112 bacterial isolates were obtained from blood and lung aspirates in 110 children (11.5%), with the most common organisms being Staphylococcus aureus (n=47) and Streptococcus pneumoniae (n=22). In subgroup analysis, bacteraemia with any organism increased the risk of treatment failure at 21 days in the chloramphenicol group (2.09, 1.41 to 3.10) but not in the ampicillin plus gentamicin group (1.12, 0.59 to 2.13). Similarly, isolation of S pneumoniae increased the risk of treatment failure at day 21 (4.06, 2.73 to 6.03) and death (5.80, 2.62 to 12.85) in the chloramphenicol group but not in the ampicillin plus gentamicin group. No difference was found in treatment failure for children with S aureus bacteraemia in the two groups, but the power to detect a difference in this subgroup analysis was low. Independent predictors of treatment failure by multivariate analysis were hypoxaemia (oxygen saturation <90%), receiving chloramphenicol, being female, and poor immunisation status. Conclusion Injectable ampicillin plus

  10. The importance of highly conserved nucleotides in the binding region of chloramphenicol at the peptidyl transfer centre of Escherichia coli 23S ribosomal RNA.

    PubMed

    Vester, B; Garrett, R A

    1988-11-01

    The peptidyl transfer site has been localized at the centre of domain V of 23S-like ribosomal RNA (rRNA) primarily on the basis of a chloramphenicol binding site. The implicated region constitutes an unstructured circle in the current secondary structural model which contains several universally conserved nucleotides. With a view to investigate the function of this RNA region further, four of these conserved nucleotides, including one indirectly implicated in chloramphenicol binding, were selected for mutation in Escherichia coli 23S rRNA using oligonucleotide primers. Mutant RNAs were expressed in vivo on a plasmid-encoded rRNA (rrnB) operon and each one yielded dramatically altered phenotypes. Cells exhibiting A2060----C or A2450----C transversions were inviable and it was shown by inserting the mutated genes after a temperature-inducible promoter that the mutant RNAs were directly responsible. In addition, a G2502----A transition caused a decreased growth rate, probably due to a partial selection against mutant ribosome incorporation into polysomes, while an A2503----C transversion produced a decreased growth rate and conferred resistance to chloramphenicol. All of the mutant RNAs were incorporated into 50S subunits, but while the two lethal mutant RNAs were strongly selected against in 70S ribosomes, the plasmid-encoded A2503----C RNA was preferred over the chromosome-encoded RNA, contrary to current regulatory theories. The results establish the critical structural and functional importance of highly conserved nucleotides in the chloramphenicol binding region. A mechanistic model is also presented to explain the disruptive effect of chloramphenicol (and other antibiotics) on peptide bond formation at the ribosomal subunit interface.

  11. Contribution of the Antibiotic Chloramphenicol and Its Analogues as Precursors of Dichloroacetamide and Other Disinfection Byproducts in Drinking Water.

    PubMed

    Chu, Wenhai; Krasner, Stuart W; Gao, Naiyun; Templeton, Michael R; Yin, Daqiang

    2016-01-05

    Dichloroacetamide (DCAcAm), a disinfection byproduct, has been detected in drinking water. Previous research showed that amino acids may be DCAcAm precursors. However, other precursors may be present. This study explored the contribution of the antibiotic chloramphenicol (CAP) and two of its analogues (thiamphenicol, TAP; florfenicol, FF) (referred to collectively as CAPs), which occur in wastewater-impacted source waters, to the formation of DCAcAm. Their formation yields were compared to free and combined amino acids, and they were investigated in filtered waters from drinking-water-treatment plants, heavily wastewater-impacted natural waters, and secondary effluents from wastewater treatment plants. CAPs had greater DCAcAm formation potential than two representative amino acid precursors. However, in drinking waters with ng/L levels of CAPs, they will not contribute as much to DCAcAm formation as the μg/L levels of amino acids. Also, the effect of advanced oxidation processes (AOPs) on DCAcAm formation from CAPs in real water samples during subsequent chlorination was evaluated. Preoxidation of CAPs with AOPs reduced the formation of DCAcAm during postchlorination. The results of this study suggest that CAPs should be considered as possible precursors of DCAcAm, especially in heavily wastewater-impacted waters.

  12. Stimulation of Ribonucleic Acid Synthesis by Chloramphenicol in a rel+ Aminoacyl-Transfer Ribonucleic Acid Synthetase Mutant of Escherichia coli

    PubMed Central

    Yegian, Charles D.; Vanderslice, Rebecca W.

    1971-01-01

    Escherichia coli strain 9D3 possesses a highly temperature-sensitive valyl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.9). Since 9D3 is a rel+ strain, it cannot carry out net RNA synthesis at high temperature. A 100-μg amount of chloramphenicol (CAP) per ml added in the absence of valine cannot stimulate RNA synthesis. Either 300 μg of CAP or 100 μg of CAP plus 50 μg of valine per ml, however, promotes nearly maximal RNA synthesis. These results can be understood as follows. (i) Valyl-tRNA is required for net RNA synthesis, (ii) the synthetase lesion is incomplete, (iii) the rate of mutant acylation of tRNAval at high temperature is valine-dependent, and (iv) the CAP concentration determines the rate of residual protein synthesis. Data are also presented which demonstrate that the rate of net RNA synthesis can greatly increase long after the addition of CAP, if the amount of valyl-tRNA increases. PMID:4942766

  13. Inverse Temperature Dependence in Static Quenching versus Calorimetric Exploration: Binding Interaction of Chloramphenicol to β-Lactoglobulin.

    PubMed

    Ghosh, Narayani; Mondal, Ramakanta; Mukherjee, Saptarshi

    2015-07-28

    The binding interaction between the whey protein bovine β-lactoglobulin (βLG) with the well-known antibiotic chloramphenicol (Clp) is explored by monitoring the intrinsic fluorescence of βLG. Steady-state and time-resolved fluorescence spectral data reveal that quenching of βLG fluorescence proceeds through ground state complex formation, i.e., static quenching mechanism. However, the drug-protein binding constant is found to vary proportionately with temperature. This anomalous result is explained on the basis of the Arrhenius theory which states that the rate constant varies proportionally with temperature. Thermodynamic parameters like ΔH, ΔS, ΔG, and the stoichiometry for the binding interaction have been estimated by isothermal titration calorimetric (ITC) study. Thermodynamic data show that the binding phenomenon is mainly an entropy driven process suggesting the major role of hydrophobic interaction forces in the Clp-βLG binding. Constant pressure heat capacity change (ΔCp) has been calculated from enthalpy of binding at different temperatures which reveals that hydrophobic interaction is the major operating force. The inverse temperature dependence in static quenching is however resolved from ITC data which show that the binding constant regularly decreases with increase in temperature. The modification of native protein conformation due to binding of drug has been monitored by circular dichroism (CD) spectroscopy. The probable binding location of Clp inside βLG is explored from AutoDock based blind docking simulation.

  14. Genetic basis of the association of resistance genes mef(I) (macrolides) and catQ (chloramphenicol) in streptococci.

    PubMed

    Mingoia, Marina; Morici, Eleonora; Brenciani, Andrea; Giovanetti, Eleonora; Varaldo, Pietro E

    2014-01-01

    In streptococci mef(I) and catQ, two relatively uncommon macrolide and chloramphenicol resistance genes, respectively, are typically linked in a genetic module designated IQ module. Though variable, the module consistently encompasses, and is sometimes reduced to, a conserved ∼5.8-kb mef(I)-catQ fragment. The prototype IQ module was described in Streptococcus pneumoniae. IQ-like modules have subsequently been detected in Streptococcus pyogenes and in different species of viridans group streptococci, where mef(E) may be found instead of mef(I). Three genetic elements, one carrying the prototype IQ module from S. pneumoniae and two carrying different, defective IQ modules from S. pyogenes, have recently been characterized. All are integrative and conjugative elements (ICEs) belonging to the Tn5253 family, and have been designated ICESpn529IQ, ICESpy029IQ and ICESpy005IQ, respectively. ICESpy029IQ and ICESpy005IQ were the first Tn5253 family ICEs to be described in S. pyogenes. A wealth of new information has been obtained by comparing their genetic organization, chromosomal integration, and transferability. The origin of the IQ module is unknown. The mechanism by which it spreads in streptococci is discussed.

  15. Development of Suberin Fatty Acids and Chloramphenicol-Loaded Antimicrobial Electrospun Nanofibrous Mats Intended for Wound Therapy.

    PubMed

    Tamm, Ingrid; Heinämäki, Jyrki; Laidmäe, Ivo; Rammo, Liisi; Paaver, Urve; Ingebrigtsen, Sveinung G; Škalko-Basnet, Nataša; Halenius, Anna; Yliruusi, Jouko; Pitkänen, Pauliina; Alakurtti, Sami; Kogermann, Karin

    2016-03-01

    Suberin fatty acids (SFAs) isolated from outer birch bark were investigated as an antimicrobial agent and biomaterial in nanofibrous mats intended for wound treatment. Electrospinning (ES) was used in preparing the composite nonwoven nanomats containing chloramphenicol (CAM; as a primary antimicrobial drug), SFAs, and polyvinylpyrrolidone (as a carrier polymer for ES). The X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy, and texture analysis were used for the physicochemical and mechanical characterization of the nanomats. ES produced nanofibrous mats with uniform structure and with an average fiber diameter ranging from 370 to 425 nm. Microcrystalline SFAs and crystalline CAM were found to undergo a solid-state transformation during ES processing. The ES process caused also the loss of CAM in the final nanofibers. In the texture analysis, the SFAs containing nanofibers exhibited significantly higher maximum detachment force to an isolated pig skin (p < 0.05) than that obtained with the reference nanofibers. CAM exists in an amorphous form in the nanofibers which needs to be taken into account in controlling the physical storage stability. In conclusion, homogeneous composite nanofibrous mats for wound healing can be electrospun from the ternary mixture(s) of CAM, SFAs, and polyvinylpyrrolidone. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  16. Synergy against extensively drug-resistant Acinetobacter baumannii in vitro by two old antibiotics: colistin and chloramphenicol.

    PubMed

    Wei, Wen-Juan; Yang, Hai-Fei

    2017-03-01

    Combination antimicrobial therapy is an important option in the fight against Gram-negative 'superbugs'. This study systematically investigated the synergistic effect of colistin (CST) and chloramphenicol (CHL) in combination against extensively drug-resistant Acinetobacter baumannii (XDR-AB). The microtitre plate chequerboard assay was used to test synergy against 50 XDR-AB clinical strains. Then, three XDR-AB clinical isolates and the type strain A. baumannii ATCC 19606 were chosen for further synergy studies using time-kill assay, mutant prevention concentration (MPC) assay and real-time population analysis profile (PAP) assay. In the chequerboard assays, synergistic or additive effects [defined as a fractional inhibitory concentration index (FICI) of ≤0.5 and 0.5 < FICI < 1, respectively] were observed in all 50 isolates. In further synergy testing, the results of time-kill assays indicated that CST monotherapy produced rapid bacterial killing followed by rapid re-growth, with the emergence of CST resistance; CHL monotherapy was largely ineffective. The combination CST/CHL, however, showed a synergistic effect and enhanced bacterial killing in the four tested strains. It also significantly delayed re-growth and suppressed the emergence of CST resistance. In the MPC assay, a decrease in MPCs for CST was observed in the two CST-susceptible strains. PAP assay showed that both CST-resistant strains were heteroresistant.

  17. A label-free photoelectrochemical aptasensor based on nitrogen-doped graphene quantum dots for chloramphenicol determination.

    PubMed

    Liu, Yong; Yan, Kai; Okoth, Otieno Kevin; Zhang, Jingdong

    2015-12-15

    A photoelectrochemical (PEC) sensing platform for chloramphenicol (CAP) detection was constructed using nitrogen-doped graphene quantum dots (N-GQDs) as transducer species and label-free aptamer as biological recognition element. N-GQDs, synthesized via a facile one-step hydrothermal method, were explored to achieve highly efficient photon-to-electricity conversion under visible light irradiation. The obtained N-GQDs were characterized by transmission electron microscopy (TEM), which displayed a narrow size distribution with a mean diameter of 2.14 nm. The X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared spectroscopic (FT-IR) analysis confirmed that nitrogen was successfully doped in GQDs. The UV-visible absorption spectra indicated that nitrogen doping obviously enhanced the absorption of GQDs in visible light region. As a result, the PEC activity of GQDs was promoted by nitrogen doping. Additionally, the π-conjugated structure of N-GQDs provided an excellent platform for aptamer immobilization via π-π stacking interaction. Such an aptamer/N-GQDs based sensor showed a linear PEC response to CAP concentration in the range of 10-250 nM with a detection limit (3 S/N) of 3.1 nM. The developed PEC aptasensor exhibited high sensitivity and selectivity, good reproducibility and high stability.

  18. Degradation and antibiotic activity reduction of chloramphenicol in aqueous solution by UV/H2O2 process.

    PubMed

    Zuorro, Antonio; Fidaleo, Marco; Fidaleo, Marcello; Lavecchia, Roberto

    2014-01-15

    The efficacy of the UV/H2O2 process to degrade the antibiotic chloramphenicol (CHL) was investigated at 20 °C using a low-pressure mercury lamp as UV source. A preliminary analysis of CHL degradation showed that the process followed apparent first-order kinetics and that an optimum H2O2 concentration existed for the degradation rate. The first-order rate constant was used as the response variable and its dependence on initial CHL and H2O2 concentrations, UV light intensity and reaction time was investigated by a central composite design based on the response surface methodology. Analysis of response surface plots revealed a large positive effect of radiation intensity, a negative effect of CHL concentration and that there was a region of H2O2 concentration leading to maximum CHL degradation. CHL solutions submitted to the UV/H2O2 process were characterized by TOC and their activity against Escherichia coli and Staphylococcus aureus was assessed. No residual antibiotic activity was detected, even at CHL concentrations higher than those used in the designed experiments. Overall, the obtained results strongly support the possibility of reducing the risks associated with the release of CHL into the environment, including the spread of antibiotic resistance, by the UV/H2O2 process.

  19. Cometabolic degradation of chloramphenicol via a meta-cleavage pathway in a microbial fuel cell and its microbial community.

    PubMed

    Zhang, Qinghua; Zhang, Yanyan; Li, Daping

    2017-04-01

    The performance of a microbial fuel cell (MFC) in terms of degradation of chloramphenicol (CAP) was investigated. Approximately 84% of 50mg/L CAP was degraded within 12h in the MFC. A significant interaction of pH, temperature, and initial CAP concentration was found on removal of CAP, and a maximum degradation rate of 96.53% could theoretically be achieved at 31.48°C, a pH of 7.12, and an initial CAP concentration of 106.37mg/L. Moreover, CAP was further degraded through a ring-cleavage pathway. The antibacterial activity of CAP towards Escherichia coli ATCC 25922 and Shewanella oneidensis MR-1 was largely eliminated by MFC treatment. High-throughput sequencing analysis indicated that Azonexus, Comamonas, Nitrososphaera, Chryseobacterium, Azoarcus, Rhodococcus, and Dysgonomonas were the predominant genera in the MFC anode biofilm. In conclusion, the MFC shows potential for the treatment of antibiotic residue-containing wastewater due to its high rates of CAP removal and energy recovery.

  20. Design of elution strategy for simultaneous detection of chloramphenicol and gentamicin in complex samples using surface plasmon resonance.

    PubMed

    Xia, Yinqiang; Su, Rongxin; Huang, Renliang; Ding, Li; Wang, Libing; Qi, Wei; He, Zhimin

    2017-06-15

    For the analysis of massive samples containing multiple analytes, the enhancement of detection efficiency is crucial. In this study, a facile method was developed for sequential detection of chloramphenicol (CAP) and gentamicin (GEN) in complex samples, e.g. milk, using a surface plasmon resonance (SPR)-based biosensor. Based on the immune inhibition format, two conjugates of antigen and bovine serum albumin (BSA)-denoted as CAP-BSA and GEN-BSA-were grafted on the same channel of the SPR sensor chip. Two standard curves for CAP and GEN were separately obtained by first mixing a single antibody with different concentrations of the relevant antigen. Moreover, different regeneration solutions were screened for sequential analysis. An alkaline solution was found to completely remove the antibody against GEN (AbGEN) from the chip, but it exhibited limited ability to dissociate the antibody against CAP (AbCAP). Therefore, alkaline solution and Gly-HCl solutions are successively applied to elute AbGEN and AbCAP, respectively. By gradual elutions, CAP and GEN concentrations were simultaneously calculated with limit of detection values of 5.28ng/mL and 2.26ng/mL, respectively. Furthermore, the spiking milk samples with CAP and GEN validated the assay with recoveries of 77.6-101.1%. Therefore, this method is expected to improve the detection efficiency of SPR biosensors.

  1. Selective inhibition by chloramphenicol of pregnenolone-16. cap alpha. -carbonitrile-inducible rat liver cytochrome P-450 isozymes

    SciTech Connect

    Graves, P.E.; Kaminsky, L.S.; Halpert, J.

    1986-03-01

    Pregnenolone-16 ..cap alpha..-carbonitrile (PCN) has been shown to induce, in male rats, cytochrome P-450 isozymes responsible for the formation of R-10-hydroxywarfarin and R-dehydrowarfarin. Antibodies to the major PCN-inducible isozyme (PB/PCN-E) inhibit both activities in microsomal preparations. Recently the authors have shown that PCN treatment of female rats also induces the formation of both R-warfarin metabolites. However, in both sexes chloramphenicol (CAP) treatment selectively inhibits only the rate of formation of the R-dehydrowarfarin. A decrease in microsomal P-450 content occurs after in vivo administration of CAP to PCN-treated rats of both sexes. This is in contrast to the lack of effect of CAP on P-450 levels in phenobarbital-treated rats. Covalent binding of /sup 14/C-CAP to microsomal protein in vitro was increased 3 to 4-fold following PCN treatment. Chromatographic evidences suggests the presence of at least two PCN-induced isozymes of similar molecular weights in both male and female rat liver microsomes. These data are consistent with the multiplicity of PCN-inducible P-450 in rat liver.

  2. Development of an Immunoassay for Chloramphenicol Based on the Preparation of a Specific Single-Chain Variable Fragment Antibody.

    PubMed

    Du, Xin-jun; Zhou, Xiao-nan; Li, Ping; Sheng, Wei; Ducancel, Frédéric; Wang, Shuo

    2016-04-13

    Specific antibodies are essential for the immune detection of small molecule contaminants. In the present study, the heavy and light variable regions (V(H )and V(L)) of the immunoglobulin genes from a hybridoma secreting a chloramphenicol (CAP)-specific monoclonal antibody (mAb) were cloned and sequenced. In addition, the light and heavy chains obtained from the monoclonal antibody were separated using SDS-PAGE and analyzed using Orbitrap mass spectrometry. The results of DNA sequencing and mass spectrometry analysis were compared, and the V(H) and V(L) chains specific for CAP were determined and used to construct a single-chain variable fragment (scFv). This fragment was recombinantly expressed as a soluble scFv-alkaline phosphatase fusion protein and used to develop a direct competitive ELISA. Compared with the parent mAb, scFv exhibits lower sensitivity but better food matrix resistance. This work highlights the application of engineered antibodies for CAP detection.

  3. A sensitive fluorescent nanosensor for chloramphenicol based on molecularly imprinted polymer-capped CdTe quantum dots.

    PubMed

    Amjadi, Mohammad; Jalili, Roghayeh; Manzoori, Jamshid L

    2016-05-01

    A novel fluorescent nanosensor using molecularly imprinted silica nanospheres embedded CdTe quantum dots (CdTe@SiO2 @MIP) was developed for detection and quantification of chloramphenicol (CAP). The imprinted sensor was prepared by synthesis of molecularly imprinting polymer (MIP) on the hydrophilic CdTe quantum dots via reverse microemulsion method using small amounts of solvents. The resulting CdTe@SiO2 @MIP nanoparticles were characterized by fluorescence, UV-vis absorption and FT-IR spectroscopy and transmission electron microscopy. They preserved 48% of fluorescence quantum yield of the parent quantum dots. CAP remarkably quenched the fluorescence of prepared CdTe@SiO2 @MIP, probably via electron transfer mechanism. Under the optimal conditions, the relative fluorescence intensity of CdTe@SiO2 @MIP decreased with increasing CAP by a Stern-Volmer type equation in the concentration range of 40-500 µg L(-1). The corresponding detection limit was 5.0 µg L(-1). The intra-day and inter-day values for the precision of the proposed method were all <4%. The developed sensor had a good selectivity and was applied to determine CAP in spiked human and bovine serum and milk samples with satisfactory results. Copyright © 2015 John Wiley & Sons, Ltd.

  4. [Modification of cell damage, caused by variable rate heating, by means of changes in osmotic pressure of the medium or using chloramphenicol].

    PubMed

    Morozov, I I; Petin, V G

    1998-01-01

    We investigated the influence of media with different osmotic pressure and of chloramphenicol on cytotoxic effects of heating with different rate of Escherichia coli B/r and Escherichia coli Bs-1 bacteria, and Zygosaccharomyces bailii yeast cells. It was shown that the hypotonic media appreciably increased cytotoxic action of heating with different rate, and, on the contrary, the hypertonic media inhibited induction of these effects. The inhibitor of protein synthesis chloramphenicol was established not to affect the bacterial thermoresistance in the process of different heating rate. On the basis of analysis of the obtained and literature data, it is proposed that a reason of cell injury dependence of the heating rate may be the availability of dissimilar levels of osmotic homeostasis destabilization in these cells when heated with different rates.

  5. Heavy metal (lead, Cadmium) and antibiotic (Tetracycline and Chloramphenicol) residues in fresh and frozen fish types (Clarias gariepinus, Oreochromis niloticus) in Ibadan, Oyo State, Nigeria.

    PubMed

    Olusola, Adetunji Victoria; Folashade, Popoola Amirah; Ayoade, Odetokun Ismail

    2012-09-15

    This study was carried out to assess the level of heavy metals (lead (Pb) and cadmium (Cd)) and antibiotics (tetracycline and chloramphenicol) residues in frozen and fresh fish types obtained from Eleyele river, Officer's mess, Alfa farm and a major frozen meat outlet in Ibadan, Oyo State Nigeria. The Atomic Absorption Spectrophotometer (AAS) and High Performance Liquid Chromatography (HPLC) were used to analyze the heavy metals and antibiotics residue levels in fresh and frozen fish, respectively. The results showed mean concentrations of antibiotics was higher (p<0.05) in fresh than in frozen fish samples while there were no significant differences in the mean concentrations of heavy metal residue. The differences of mean residue levels in both antibiotics and heavy metals tested in the cranial and caudal parts of the fish samples were not significant (p<0.05). However, there was a significant difference between species (tilapia and catfish) and sources. The highest heavy metals and tetraxycline residues were observed in Alfa's farm (Pb: 0.039+/-0.004 ppm; Cd: 0.020+/-0.006 ppm; tetraxycline: 2.185+/-0.412). Chloramphenicol was highest in Officers mess (0.837+/-0.165 ppm). The heavy metals (Pb and Cd) concentrations determined were below the maximum permissible limits set by both local and international safety agencies. Tetraxcycline exceeded international limits of 0.2 ppm while Chloramphenicol which has a zero tolerance level was also detected from all sources. This study accentuates the need for control of heavy metals and antibiotics in fish sold for human consumption in Ibadan, Nigeria. The need to ban chloramphenicol in treatment of fish and other animals is emphasised.

  6. Transcription factor CecR (YbiH) regulates a set of genes affecting the sensitivity of Escherichia coli against cefoperazone and chloramphenicol.

    PubMed

    Yamanaka, Yuki; Shimada, Tomohiro; Yamamoto, Kaneyoshi; Ishihama, Akira

    2016-07-01

    Genomic SELEX (systematic evolution of ligands by exponential enrichment) screening was performed for identification of the binding site of YbiH, an as yet uncharacterized TetR-family transcription factor, on the Escherichia coli genome. YbiH was found to be a unique single-target regulator that binds in vitro within the intergenic spacer located between the divergently transcribed ybiH-ybhGFSR and rhlE operons. YbhG is an inner membrane protein and YbhFSR forms a membrane-associated ATP-binding cassette (ABC) transporter while RhlE is a ribosome-associated RNA helicase. Gel shift assay and DNase footprinting analyses indicated one clear binding site of YbiH, including a complete palindromic sequence of AATTAGTT-AACTAATT. An in vivo reporter assay indicated repression of the ybiH operon and activation of the rhlE operon by YbiH. After phenotype microarray screening, YbiH was indicated to confer resistance to chloramphenicol and cefazoline (a first-generation cephalosporin). A systematic survey of the participation of each of the predicted YbiH-regulated genes in the antibiotic sensitivity indicated involvement of the YbhFSR ABC-type transporter in the sensitivity to cefoperazone (a third-generation cephalosporin) and of the membrane protein YbhG in the control of sensitivity to chloramphenicol. Taken together with the growth test in the presence of these two antibiotics and in vitro transcription assay, it was concluded that the hitherto uncharacterized YbiH regulates transcription of both the bidirectional transcription units, the ybiH-ybhGFSR operon and the rhlE gene, which altogether are involved in the control of sensitivity to cefoperazone and chloramphenicol. We thus propose to rename YbiH as CecR (regulator of cefoperazone and chloramphenicol sensitivity).

  7. The Efficacy of 1% Chloramphenicol Eye Ointment Versus 2.5% Povidone-Iodine Ophthalmic Solution in Reducing Bacterial Colony in Newborn Conjunctivae.

    PubMed

    Bramantyo, Triwijayanti; Roeslani, Rosalina Dewi; Andriansjah, Andriansjah; Sitorus, Rita S

    2015-01-01

    This study aimed to evaluate bacterial pattern and reduction of bacterial colonies in neonatal conjunctivae after prophylaxis 1% chloramphenicol eye ointment and 2.5% povidone-iodine ophthalmic solution. A double-blind randomized controlled trial was conducted. Swabs were taken from the inferior fornix conjunctiva of the right eyes of 60 newborns 1 hour after birth. Either the 2.5% povidone-iodine ophthalmic solution or the 1% chloramphenicol eye ointment was randomly applied to the conjunctivae. Conjunctival swabs were taken 2 hours after prophylaxis treatment. Specimens were delivered to the Microbiology Laboratory to determine the number of bacterial colonies and to evaluate bacterial pattern. Sixty eye specimens were included in the study. Bacterial growth was shown in 44 eye specimens, whereas it was not found in the remaining 16 eye specimens. The bacteria found in neonatal conjunctivae was gram-positive coccus (61%), followed by gram-positive bacillus (36%) and gram-negative bacillus (2%). Both agents significantly reduced the bacterial colony-forming unit (P = 0.00); however, the effect was not significantly different as shown by statistics between both groups (P = 0.748), indicating that the 2.5% povidone-iodine ophthalmic solution had a similar effect to the 1% chloramphenicol eye ointment. No adverse effect such as toxic conjunctivitis or corneal haziness was found in both groups. The 2.5% povidone-iodine ophthalmic solution has been proven as effective as the 1% chloramphenicol eye ointment and induces no toxic reaction. Because it is less expensive than the other, it could be recommended as a good alternative for ophthalmia neonatorum prophylaxis. Further studies with a larger sample size should be conducted to confirm its cost-effectiveness.

  8. Preparation of green alga-based activated carbon with lower impregnation ratio and less activation time by potassium tartrate for adsorption of chloramphenicol.

    PubMed

    Zhu, Xiuzhen; Gao, Yuan; Yue, Qinyan; Kan, Yujiao; Kong, Wenjia; Gao, Baoyu

    2017-11-01

    Potassium tartrate (C4H6K2O7) was utilized as a novel activating agent to prepare activated carbon with relatively high specific surface area by using less activating agent and activation time from marine waste-green alga (Enteromorpha prolifera) for the first time. The influences of activation temperature, impregnation ratio and activation time on the pore structure were investigated to obtain the optimum conditions (activation temperature: 700°C, impregnation ratio: 1:1, and activation time: 30min). Meanwhile, the activation temperature was evaluated to be the essential factor that dominated the form of pore structure in activated carbon. The green alga-based activated carbon that was prepared under optimum conditions has shown the high surface area of 1692m(2)/g and total pore volume of 1.22cm(3)/g, which could be used as an effective adsorbent to remove chloramphenicol. The thermodynamic data of chloramphenicol were well fitted by Langmuir isotherm model and the green alga-based activated carbon has showed high adsorption capacity of 709.2mg/g towards chloramphenicol. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Resistance of Bacteroides isolates recovered among clinical samples from a major Costa Rican hospital between 2000 and 2008 to ß-lactams, clindamycin, metronidazole, and chloramphenicol.

    PubMed

    Cordero-Laurent, E; Rodríguez, C; Rodríguez-Cavallini, E; Gamboa-Coronado, M M; Quesada-Gómez, C

    2012-12-01

    To assess the susceptibility of 100 isolates of Bacteroides spp. recovered in a major Costa Rican hospital between 2000 and 2008 to several ß-lactams, chloramphenicol, clindamycin and metronidazole. Susceptibility to amoxicillin, amoxicillin with clavulanic acid, piperacillin, piperacillin with tazobactam, ticarcillin, ticarcillin with clavulanic acid, cefoxitin, cefotetan, imipenem, chloramphenicol, clindamycin, and metronidazole was determined with the ATB ANA® system. In addition, minimum inhibitory concentrations (MIC) of clindamycin and metronidazole were determined with the broth microdilution method because these drugs are the treatment of choice for anaerobic infections in Costa Rica. Reference strains ATCC® 25285 and ATCC® 29741 were employed as indicated. According to the ATB ANA® system, 93 isolates were resistant to at least one antibiotic. Resistance to ß-lactams was common. By contrast, resistance to ß-lactams supplemented with ß-lactamase inhibitors was rare. All of the strains were inhibited by imipenem and chloramphenicol. By a broth microdilución test, resistance to clindamycin was 20%, with MIC ranging from 64 mg/L to 256 mg/L; all of the strains were susceptible to metronidazole. The high MIC for clindamycin obtained for the majority of the resistant strains is highly suggestive of the presence of mechanisms of acquired resistance among the isolates, therefore surveillance studies are required to determine its efficacy. The low resistance to metronidazole observed underlines its value as a first-line drug. On the other hand, imipenem could be used to treat infections that do not respond well to metronidazole or clindamycin.

  10. Mitochondrial Genetics VII. Allelism and Mapping Studies of Ribosomal Mutants Resistant to Chloramphenicol, Erythromycin and Spiramycin in S. CEREVISIAE

    PubMed Central

    Netter, Pierre; Petrochilo, Eric; Slonimski, Piotr P.; Bolotin-Fukuhara, Monique; Coen, Dario; Deutsch, Jean; Dujon, Bernard

    1974-01-01

    We have isolated 15 spontaneous mutants resistant to one or several antibiotics like chloramphenicol, erythromycin and spiramycin. We have shown by several criteria that all of them result from mutations localized in the mitochondrial DNA. The mutations have been mapped by allelism tests and by two- and three-factor crosses involving various configurations of resistant and sensitive alleles associated in cis or in trans with the mitochondrial locus ω which governs the polarity of genetic recombination. A general mapping procedure based on results of heterosexual (ω+ x ω-) crosses and applicable to mutations localized in the polar segment is described and shown to be more resolving than that based on results of homosexual crosses. Mutations fall into three loci which are all linked and map in the following order: ω–RI–RII–RIII. The first locus is very tightly linked with ω while the second is less linked to the first. Mutations of similar resistance phenotype can belong to different loci and different phenotypes to the same locus. Mutations confer antibiotic resistance on isolated mitochondrial ribosomes and delineate a ribosomal segment of the mitochondrial DNA. Homo- and hetero-sexual crosses between mutants of the ribosomal segment and those belonging to the genetically unlinked ATPase locus, OI, have been performed in various allele configurations. The polarity of recombination between RI, RII, RIII and OI decreases as a function of the distance of the R locus from the ω locus rather than as a function of the distance of the R locus from the OI locus. PMID:4281750

  11. Determination of chloramphenicol in honey, milk, and egg by liquid chromatography/mass spectrometry: single-laboratory validation.

    PubMed

    Ozcan, Nihat; Aycan, Ozlem

    2013-01-01

    This study describes determination of chloramphenicol (CAP) in honey, milk, and egg by LC-electrospray ionization (ESI)-MS. CAP was extracted with ethyl acetate from honey, and with acetonitrile from milk and egg. d5-CAP was used as the internal standard. Separation was achieved on a ZORBAX Eclipse C18 2.1 id, 150 mm, 2.1 pm column. The mass spectrometer was equipped with an ESI interface in negative mode. Mass determination of CAP and d5-CAP was carried out in selected ion monitoring mode by scanning m/z 321 for CAP and m/z 326 for d5-CAP as quantification ions, and m/z 323 as the confirmation ion. The validation of the analytical method was performed by carrying out linearity, LOD, LOQ, accuracy, precision, and recovery. Calibration curve was linear between 0.1 and 20.0 ng/g with correlation coefficient >0.998. Accuracy of the method for the honey sample was 95%, and for the milk powder sample 106%. Precision of the method, expressed as CV%, varied between 1.60 and 4.37 for intraday and 2.00 to 5.67 for interday. Quantification limits of method were 0.05, 0.08, and 0.09 ng/g for egg, milk, and honey, respectively. Recovery of the method ranged between 86 and 103% for all three matrixes and two different concentrations. Finally, the method was checked by participating proficiency tests from the Food Analysis Performance and Assessment Scheme 0281 and 0298 honey samples. Z scores were -1.0 and 0.4, respectively.

  12. Selection of scFv phages specific for chloramphenicol acetyl transferase (CAT), as alternatives for antibodies in CAT detection assays.

    PubMed

    Van Dorst, Bieke; Mehta, Jaytry; Rouah-Martin, Elsa; Backeljau, Jelke; De Coen, Wim; Eeckhout, Dominique; De Jaeger, Geert; Blust, Ronny; Robbens, Johan

    2012-10-01

    Reporter gene assays are commonly used in applied toxicology to measure the transcription of genes involved in toxic responses. In these reporter gene assays, transgenic cells are used, which contain a promoter-operator region of a gene of interest fused to a reporter gene. The transcription of the gene of interest can be measured by the detection of the reporter protein. Chloramphenicol acetyl transferase (CAT) is frequently used as a reporter protein in mammalian reporter gene assays. Although CAT can be measured by different detection systems, like enzymatic and immune assays, most of these tests are expensive, time-consuming and labor-intensive. The excellent characteristics of phages, like their high affinity and specificity, their fast, cheap and animal-friendly manufacturing process with low batch-to-batch variations and their stability, make them appropriate as alternatives for antibodies in detection assays. Therefore, in this study single-chain variable fragment (scFv) phages were selected with affinity for CAT. Several scFv phages were selected that showed affinity towards CAT in a screening ELISA. Surface plasmon resonance analyses showed that the tested scFv phages have an affinity for CAT with a dissociation constant (K(d)) around 1 µM. The selected scFv phages in this study could be used as capture elements in a highly sensitive sandwich ELISA to detect CAT concentration as low as 0.1 ng ml⁻¹ or 4 pM. This low detection limit demonstrates the potential of the scFv phages as an alternative for capturing antibodies in a highly sensitive detection test to measure CAT concentrations in reporter gene assays.

  13. Photocatalytic degradation of chloramphenicol in an aqueous suspension of silver-doped TiO2 nanoparticles.

    PubMed

    Shokri, Mohammad; Jodat, Akbar; Modirshahla, Nasser; Behnajady, Mohammad A

    2013-01-01

    In this work, silver-doped TiO2 (Ag/TiO2) nanoparticles were synthesized using a photodeposition technique. The prepared Ag/TiO2 nanoparticles were characterized using TEM, SEM, XRD, and EDX techniques. The characterization of Ag/TiO2 nanoparticles using SEM and EDX techniques revealed the dispersion of Ag metal on the surface of TiO2. The photocatalytic activity of Ag/TiO2 and bare TiO2 in the presence of ultraviolet irradiation was investigated in the removal of chloramphenicol (CAP) as an antibiotic. CAP is a broad-spectrum antibiotic exhibiting activity against both Gram-positive and Gram-negative bacteria, as well as other groups of microorganisms. However, it is, in certain susceptible individuals, associated with serious toxic effects in humans including bone marrow depression, particularly severe in the form of fatal aplastic anaemia. The effects of the operational factors, such as doping content of Ag, photocatalyst dosage and calcination temperature were evaluated in the catalytic activity of Ag/TiO2. The results showed that the photocatalytic efficiency of TiO2 nanoparticles for the degradation of CAP, can be significantly improved by deposition an optimum amount of Ag nanoparticles (0.96 wt%) in the calcination temperature 300 degrees C. It was found that 900 mg/L of Ag/TiO2 is the optimum dosage in the removal of CAP with 20 mg/L initial concentration. The highest removal efficiency of CAP (-100%) at the optimum conditions was observed in 20 min. A mineralization study under optimum conditions showed about 88% reduction in total organic carbon after 120 min of irradiation time.

  14. A portable and antibody-free sandwich assay for determination of chloramphenicol in food based on a personal glucose meter.

    PubMed

    Chen, Si; Gan, Ning; Zhang, Huairong; Hu, Futao; Li, Tianhua; Cui, Huan; Cao, Yuting; Jiang, Qianli

    2015-03-01

    A portable and antibody-free sandwich assay was fabricated for determination of chloramphenicol (CAP) in animal-derived food by a personal glucose meter (PGM). The sandwich-type strategy was developed on the basis of magnetic molecularly imprinted probe (m-MIP) nanoparticles and a β-cyclodextrin/invertase-functionalized signal tag. Firstly, the m-MIPs were fabricated using polydopamine molecularly imprinted film modified Fe3O4 nanoparticles with 2,2-dichloroacetamide as a template that could capture the 2,2-dichloroacetamide segment of CAP. Secondly, β-cyclodextrin/invertase polymer bioconjungate was synthesized as a signal tag that could recognize the nitrobenzene segment of CAP through host-guest interaction. The dual-specificity recognition model relies on the formation of a sandwich between m-MIPs, different segments of CAP, and the β-cyclodextrin-functionalized signal tag. The sandwich-type complex formed was then subjected to detection with a PGM. The complexes can hydrolyze sucrose to glucose, which can be used for detection with a PGM through invertase. According to our experiment, the concentration of CAP was proportional to the amount of glucose formed, which could quantitatively assess the CAP with a dynamic range of 0.5-50 ng mL(-1) and a detection limit of 0.16 ng mL(-1) (signal-to-noise ratio of 3). The detection time of the assay was about 1 h, which was obviously shorter than that of competitive ELISA. More importantly, we have successfully applied this on-site assay for CAP screening in animal-derived food.

  15. Comparsion of an immunochromatographic strip with ELISA for simultaneous detection of thiamphenicol, florfenicol and chloramphenicol in food samples.

    PubMed

    Guo, Lingling; Song, Shanshan; Liu, Liqiang; Peng, Juan; Kuang, Hua; Xu, Chuanlai

    2015-09-01

    Rapid and sensitive indirect competitive enzyme-linked immunosorbent assays (ic-ELISA) and gold nanoparticle immunochromatographic strip tests were developed to detect thiamphenicol (TAP), florfenicol (FF) and chloramphenicol (CAP) in milk and honey samples. The generic monoclonal antibody for TAP, FF and CAP was prepared based on a hapten [D-threo-1-(4-aminophenyl)-2- dichloroacetylamino-1,3-propanediol], and the haptenwas linked to a carrier protein using the diazotization method. After the optimization of several parameters (coating, pH, sodium chloride content and methanol content), the ic-ELISA was established. The quantitative working range for TAP was 0.11-1.36 ng/mL, with an IC50 of 0.39 ng/mL. The optimized ELISA showed cross-reactivity to CAP (300%) and FF (15.6%), with IC50 values of 0.13 and 2.5 ng/mL, respectively. The analytical recovery of TAP, FF and CAP in milk and honey samples in the ic-ELISA ranged from 81.2 to 112.9%. Based on this monoclonal antibody, a rapid and sensitive immunochromatographic test strip was also developed. This strip had a detection limit of 1 ng/mL for TAP, FF and CAP in milk and honey samples. Moreover, the test was completed within 10 min. Our results showed that the proposed ic-ELISA and immunochromatographic test strip method are highly useful screening tools for TAP, FF and CAP detection in milk and honey samples. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Successful co-encapsulation of benzoyl peroxide and chloramphenicol in liposomes by a novel manufacturing method - dual asymmetric centrifugation.

    PubMed

    Ingebrigtsen, Sveinung G; Škalko-Basnet, Nataša; de Albuquerque Cavalcanti Jacobsen, Cristiane; Holsæter, Ann Mari

    2017-01-15

    Encapsulation of more than one active pharmaceutical ingredient into nanocarriers such as liposomes is an attractive approach to achieve a synergic drug effect and less complicated dosing schedules in multi-drug treatment regimes. Liposomal drug delivery in acne treatment may improve drug efficiency by targeted delivery to pilosebaceous units, reduce adverse effects and improve patient compliance. We therefore aimed to co-encapsulate benzoyl peroxide (BPO) and chloramphenicol (CAM) into liposomes using the novel liposome processing method - dual asymmetric centrifugation (DAC). Liposomes were formed from soybean lecithin, propylene glycol and distilled water (2:1:2w/v/v ratio), forming a viscous liposome dispersion. Liposomes containing both drugs (BPO-CAM-Lip), single drug (BPO-Lip and CAM-Lip), and empty liposomes were prepared. Drug entrapment of BPO and CAM was determined by a newly developed HPLC method for simultaneous detection and quantification of both drugs. Encapsulation of around 50% for BPO and 60% for CAM respectively was obtained in both single-drug encapsulated formulations (BPO-Lip and CAM-Lip) and co-encapsulated formulations (BPO-CAM-Lip). Liposome sizes were comparable for all liposome formulations, ranging from 130 to 150nm mean diameter, with a polydispersity index <0.2 for all formulations. CAM exhibited a sustained release from all liposomal formulations, whereas BPO appeared retained within the liposomes. BPO retention could be attributed to its poor solubility. However, HaCaT cell toxicity was found dependent on BPO released from the liposomes. In the higher concentration range (4%v/v), liposomal formulations were less cytotoxic than the corresponding drug solutions used as reference. We have demonstrated that DAC is a fast, easy, suitable method for encapsulation of more than one drug within the same liposomes.

  17. The pdx genetic marker adjacent to the chloramphenicol biosynthesis gene cluster in Streptomyces venezuelae ISP5230: functional characterization.

    PubMed

    Magarvey, N; He, J; Aidoo, K A; Vining, L C

    2001-08-01

    The pdx-4 mutation in Streptomyces venezuelae ISP5230 confers a growth requirement for pyridoxal (pdx) and is a marker for the genetically mapped cluster of genes associated with chloramphenicol biosynthesis. A gene regulating salvage synthesis of vitamin B6 cofactors in S. venezuelae was cloned by transforming a pdx-4 mutant host with the plasmid vector pDQ101 carrying a library of wild-type genomic DNA fragments, and by selecting for complementation of the host's pdx requirement. However, the corresponding replicative plasmid could not be isolated. Southern hybridizations and transduction analysis indicated that the complementing plasmid had integrated into the chromosome; after excision by a second crossover, the plasmid failed to propagate. To avoid loss of the recombinant vector, a pdx-dependent Streptomyces lividans mutant, KAA1, with a phenotype matching that of S. venezuelae pdx-4, was isolated for use as the cloning host. Introduction of pIJ702 carrying an S. venezuelae genomic library into S. lividans KAA1, and selection of prototrophic transformants, led to the isolation of a stable recombinant vector containing a 2.5 kb S. venezuelae DNA fragment that complemented requirements for pdx in both S. venezuelae and S. lividans mutants. Sequence analysis of the cloned DNA located an intact ORF with a deduced amino acid sequence that, in its central and C-terminal regions resembled type-I aminotransferases. The N-terminal region of the cloned DNA fragment aligned closely with distinctive helix-turn-helix motifs found near the N termini of GntR family transcriptional regulators. The overall deduced amino acid sequence of the cloned DNA showed 73% end-to-end identity to a putative GntR-type regulator cloned in cosmid 6D7 from the Streptomyces coelicolor A3(2) genome. This location is close to that of pdxA, the first pdx marker in S. coelicolor A3(2) identified and mapped genetically in Sir David Hopwood's laboratory. The S. venezuelae gene and S. coelicolor pdx

  18. Enantioselective analysis of chloramphenicol residues in honey samples by chiral LC-MS/MS and results of a honey survey.

    PubMed

    Rimkus, Gerhard G; Hoffmann, Dirk

    2017-06-01

    Chloramphenicol (CAP) is a broad-spectrum antibiotic used widely in both human and veterinary medication. Since 1994, CAP has not been authorised for use in food-producing animals in the European Union due to several adverse effects. A minimum required performance level (MRPL) of 0.3 µg kg(-)(1) was established in 2003. The CAP molecule contains two asymmetric centres, thus in total four para-CAP stereoisomers exist. Only the RR-CAP enantiomer is bioactive, having significant antimicrobial activity. For the first time a chiral LC-MS/MS method is reported to identify and quantify the four CAP enantiomers at residue levels in honey samples. The method was validated at two concentration levels. The decision limits (CCα) and detection capabilities (CCß) were well below 0.3 µg kg(-)(1), with limits of quantification (LOQs) between 0.08 and 0.12 µg kg(-)(1) for all four enantiomers. The method provides a sensitive and reliable analysis of CAP enantiomers in honey, and proved its robustness during the daily routine analyses of numerous honey samples. In an internal honey survey, in total 40 honey samples from different geographical regions with identified CAP residues at or above the MRPL were reanalysed by chiral LC-MS/MS. In nine honey samples only the bioactive RR-CAP was detected as anticipated. However, in all other 31 honey samples the non-bioactive SS-CAP was also identified and quantified unambiguously. In 10 of these samples, mixtures of RR- and SS-CAP were analysed, and in 21 samples only the SS-CAP enantiomer, with concentrations up to 2.2 µg kg(-)(1). Most of these samples are honeys from Ukraine and Eastern Europe. This is the first report of SS-CAP residues in food samples. The potential sources for these findings are discussed and the need of further systematic studies emphasised. It is recommended to examine in more depth the toxicological profile of the individual CAP stereoisomers.

  19. Chloramphenicol and tetracycline decrease motility and increase invasion and attachment gene expression in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    PubMed Central

    Brunelle, Brian W.; Bearson, Bradley L.; Bearson, Shawn M. D.

    2015-01-01

    Salmonella enterica serovar Typhimurium is one of the most common serovars isolated from humans and livestock, and over 35% of these isolates are resistant to three or more antibiotics. Multidrug-resistant (MDR) Salmonella is a public health concern as it is associated with increased morbidity in patients compared to antibiotic sensitive strains, though it is unknown how the antibiotic resistant isolates lead to a more severe infection. Cellular invasion is temporally regulated in Salmonella and normally occurs during late-log and stationary growth. However, our previous work determined that a 30 min exposure to a sub-inhibitory concentration of tetracycline can induce the full invasion phenotype during early-log growth in certain MDR S. Typhimurium isolates. The current study examined whether sub-inhibitory concentrations of other antibiotics could also induce the invasiveness in the same set of isolates. Ampicillin and streptomycin had no effect on invasion, but certain concentrations of chloramphenicol were found to induce invasion in a subset of isolates. Two of the isolates induced by chloramphenicol were also inducible by tetracycline. RNA-seq analyses demonstrated that chloramphenicol and tetracycline both down-regulated motility gene expression, while up-regulating genes associated with attachment, invasion, and intracellular survival. Eleven fimbrial operons were up-regulated, which is notable as only three fimbrial operons were thought to be inducible in culture; six of these up-regulated operons have been reported to play a role in Salmonella persistence in mice. Overall, these data show that the normal progression of the genetic pathways that regulate invasion can be expedited to occur within 30 min due to antibiotic exposure. This altered invasion process due to antibiotics may play a role in the increased intensity and duration of infection observed in patients with MDR Salmonella. PMID:25688233

  20. Colorimetric determination of 1-(4'-nitrophenyl)-2-aminopropane-1,3-diol with 2,4,6-trinitrobenzenesulfonic acid in the presence of chloramphenicol.

    PubMed

    Pietta, P G; Agnellini, D; Pace, M

    1979-12-01

    A colorimetric method based on the interaction between the chloramphenicol degradation product 1-(4'-nitrophenyl)-2-aminopropane-1,3-diol and the 2,4,6-trinitrobenzenesulfonic acid reagent was developed. Analytical solutions were reacted with the reagent at pH 9.1 for 20 min at room temperature, and the resulting color was measured at 340 nm. A linear relationship between absorbance and concentration occurred within the 5--25-micrograms/ml range under the conditions studied. Replicate analyses were in good agreement. An average recovery of 99.4 +/- 0.4% was obtained for the synthetic mixtures.

  1. A high-throughput method for determining chloramphenicol residues in poultry, egg, shrimp, fish, swine and bovine using LC-ESI-MS/MS.

    PubMed

    Rocha Siqueira, Silvia Regina; Luiz Donato, José; de Nucci, Gilberto; Reyes, Felix Guillermo Reyes

    2009-12-01

    A LC-ESI-MS/MS method for determining chloramphenicol residues in fish, shrimp, poultry, eggs, bovine and swine was developed and validated. The samples were extracted with a phosphate extraction solution followed by liquid-liquid extraction with ethyl acetate. The LC was performed on a C18 column at room temperature. For all the matrices, the analytical curves showed r values and recoveries higher than 0.99 and 50%, respectively. The accuracy values lay between 85 and 120% and the precision was lower than 20%. The LOQ was 0.1 ng/g. The method was employed to analyze samples collected in Brazil.

  2. Simultaneous determination of chloramphenicol, dexamethasone and naphazoline in ternary and quaternary mixtures by RP-HPLC, derivative and wavelet transforms of UV ratio spectra

    NASA Astrophysics Data System (ADS)

    Hoang, Vu Dang; Hue, Nguyen Thu; Tho, Nguyen Huu; Nguyen, Hue Minh Thi

    2015-03-01

    The application of chemometrics-assisted UV spectrophotometry and RP-HPLC to the simultaneous determination of chloramphenicol, dexamethasone and naphazoline in ternary and quaternary mixtures is presented. The spectrophotometric procedure is based on the first-order derivative and wavelet transforms of ratio spectra using single, double and successive divisors. The ratio spectra were differentiated and smoothed using Savitzky-Golay filter; whereas wavelet transform realized with wavelet functions (i.e. db6, gaus5 and coif3) to obtain highest spectral recoveries. For the RP-HPLC procedure, the separation was achieved on a ZORBAX SB-C18 (150 × 4.6 mm; 5 μm) column at ambient temperature and the total run time was less than 7 min. A mixture of acetonitrile - 25 mM phosphate buffer pH 3 (27:73, v/v) was used as the mobile phase at a flow rate of 1.0 mL/min and the effluent monitored by measuring absorbance at 220 nm. Calibration graphs were established in the range 20-70 mg/L for chloramphenicol, 6-14 mg/L for dexamethasone and 3-8 mg/L for naphazoline (R2 > 0.990). The RP-HPLC and ratio spectra transformed by a combination of derivative-wavelet algorithms proved to be able to successfully determine all analytes in commercial eye drop formulations without sample matrix interference (mean percent recoveries, 97.4-104.3%).

  3. Simultaneous determination of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk by ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Wang, Yuanyuan; Li, Xiaowei; Zhang, Zhiwen; Ding, Shuangyang; Jiang, Haiyang; Li, Jiancheng; Shen, Jianzhong; Xia, Xi

    2016-02-01

    A sensitive, confirmatory ultra-high performance liquid chromatography-tandem mass spectrometric method was developed and validated to detect 23 veterinary drugs and metabolites (nitroimidazoles, benzimidazoles, and chloramphenicol components) in bovine milk. Compounds of interest were sequentially extracted from milk with acetonitrile and basified acetonitrile using sodium chloride to induce liquid-liquid partition. The extract was purified on a mixed mode solid-phase extraction cartridge. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged analytes in a 9 min chromatography run time. Recoveries based on matrix-matched calibrations and isotope labeled internal standards for milk ranged from 51.7% to 101.8%. The detection limits and quantitation limits of the analytical method were found to be within the range of 2-20 ng/kg and 5-50 ng/kg, respectively. The recommended method is simple, specific, and reliable for the routine monitoring of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk samples.

  4. Comparison of different calibration approaches for chloramphenicol quantification in chicken muscle by ultra-high pressure liquid chromatography tandem mass spectrometry.

    PubMed

    Pan, Xiao-Dong; Jiang, Wei; Wu, Ping-Gu

    2015-01-07

    Matrix-dependent signal suppression often occurs in quantitative analysis by ultra-high pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS). In this study, we investigated three calibration methods for compensation of signal suppression on chloramphenicol (CAP) quantification in chicken muscle. The data showed that the spiking recoveries by solvent standard calibration with a stable isotope labelled internal standard (SIL-IS) and matrix-matched standard calibration with a SIL-IS were significantly higher than by external matrix-matched standard calibration (P < 0.05). When the SIL-IS was used, standards prepared in the mobile phase solvent showed no significant difference as those prepared in the matrix (P > 0.05). The limit of detection (LOD) for external matrix matched standard calibration was 0.1 μg kg(-1), and that for SIL-IS calibration (including matrix matched and solvent dissolved standard) was 0.03 μg kg(-1).

  5. Simultaneous determination of chloramphenicol, dexamethasone and naphazoline in ternary and quaternary mixtures by RP-HPLC, derivative and wavelet transforms of UV ratio spectra.

    PubMed

    Hoang, Vu Dang; Hue, Nguyen Thu; Tho, Nguyen Huu; Nguyen, Hue Minh Thi

    2015-03-15

    The application of chemometrics-assisted UV spectrophotometry and RP-HPLC to the simultaneous determination of chloramphenicol, dexamethasone and naphazoline in ternary and quaternary mixtures is presented. The spectrophotometric procedure is based on the first-order derivative and wavelet transforms of ratio spectra using single, double and successive divisors. The ratio spectra were differentiated and smoothed using Savitzky-Golay filter; whereas wavelet transform realized with wavelet functions (i.e. db6, gaus5 and coif3) to obtain highest spectral recoveries. For the RP-HPLC procedure, the separation was achieved on a ZORBAX SB-C18 (150×4.6 mm; 5 μm) column at ambient temperature and the total run time was less than 7 min. A mixture of acetonitrile - 25 mM phosphate buffer pH 3 (27:73, v/v) was used as the mobile phase at a flow rate of 1.0 mL/min and the effluent monitored by measuring absorbance at 220 nm. Calibration graphs were established in the range 20-70 mg/L for chloramphenicol, 6-14 mg/L for dexamethasone and 3-8 mg/L for naphazoline (R(2)>0.990). The RP-HPLC and ratio spectra transformed by a combination of derivative-wavelet algorithms proved to be able to successfully determine all analytes in commercial eye drop formulations without sample matrix interference (mean percent recoveries, 97.4-104.3%). Copyright © 2014 Elsevier B.V. All rights reserved.

  6. In-vitro permeability of the human nail and of a keratin membrane from bovine hooves: penetration of chloramphenicol from lipophilic vehicles and a nail lacquer.

    PubMed

    Mertin, D; Lippold, B C

    1997-03-01

    Lipophilic vehicles and especially nail lacquers are more appropriate for topical application on the nail than aqueous systems because of their better adhesion. This work has, therefore, studied the penetration through the human nail plate of the model compound chloramphenicol from the lipophilic vehicles medium chain triglycerides and n-octanol and from a lacquer based on quaternary poly(methyl methacrylates) (Eudragit RL). The results were compared with data obtained with a keratin membrane from bovine hooves. If the swelling of the nail plate or the hoof membrane is not altered by use of lipophilic vehicles, the maximum flux of the drug is independent of its solubility in the vehicle and is the same as that from a saturated aqueous solution. These vehicles are not able to enter the hydrophilic keratin membrane because of their non-polar character and so cannot change the solubility of the penetrating substance in the barrier. If the concentration of the drug in the nail lacquer is sufficiently high, the maximum flux through both barriers equals that from aqueous vehicles or even exceeds it because of the formation of a supersaturated system. Penetration through the nail plate follows first order kinetics after a lag-time of 400 h. The course of penetration through the hoof membrane is initially membrane-controlled and later becomes a matrix-controlled process because of the membrane's greater permeability. Chloramphenicol is dissolved in the lacquer up to a concentration of 31%. The relative release rates from these solution matrices are independent of the drug concentration but they decrease on changing to a suspension matrix. These results show that drug flux is independent of the character of the vehicle and that penetration of the drug is initially membrane-controlled and changes to being matrix-controlled as the drug content of the lacquer decreases.

  7. Quantitative Analysis of Chloramphenicol in Royal Jelly by Column-switching LC-MS/MS Using a Pretreatment Column with a Higher-pressure Capability.

    PubMed

    Kawano, Shin-ichi; Hayakawa, Yoshihiro; Hashi, Yuki; Lin, Jin-Ming

    2015-01-01

    An on-line pretreatment liquid chromatography-tandem mass spectrometry (LC-MS/MS) system was developed for the analysis of chloramphenicol (CAP) in royal jelly. A novel methylcellulose-immobilized restricted access media column with a higher-pressure capability of 60 MPa (MC-ODS HP) was developed for the effective removal of proteins and other compounds in the sample matrix. CAP in a sample solution was extracted in 2 min by the column-switching LC-MS/MS system. The system provides a minimum sample pretreatment along with highly sensitive and reproducible analysis. As a result, the limit of quantitation of CAP was 10 pg/mL (= 0.1 μg/kg royal jelly) and the linear dynamic range was between 10 and 10000 pg/mL (correlation coefficient greater than 0.999). The proposed method meets the requirements of regulations in EU (0.3 μg/kg). The inter-day precision and accuracy of CAP at 100 pg/mL over 3 days were 4.5 and 95.4%, respectively. Compared with the conventional method with a pressure of below 25 MPa, the peak separation in the MRM chromatogram was improved by using smaller particles (1.6 μm) for the analytical ODS column. The LC-MS/MS system with an MC-ODS HP expanded the applicability of the automated pretreatment.

  8. Increased formation of halomethanes during chlorination of chloramphenicol in drinking water by UV irradiation, persulfate oxidation, and combined UV/persulfate pre-treatments.

    PubMed

    Wenhai, Chu; Tengfei, Chu; Erdeng, Du; Deng, Yang; Yingqing, Guo; Naiyun, Gao

    2016-02-01

    Ultraviolet/persulfate (UV/PS) has been widely used to generate sulfate radicals for degradation of water organic pollutants in previous studies. However, its impacts on disinfection byproduct formation during post-chlorination of degraded compounds is unclear. The objective of this study was to evaluate the impacts of UV irradiation, PS oxidation, and the combined UV/PS advanced oxidation process (AOP) pre-treatments on halomethane formation during the following chlorination of chloramphenicol (CAP), a model antibiotic commonly found in wastewater-impacted water. Results showed that CAP could be transformed to more trichloromethane (TCM) than monochloromethane (MCM) and dichloromethane (DCM) in the presence of excess chlorine. UV photolysis, PS oxidation and UV/PS AOP all directly decomposed CAP to produce halomethanes (HMs) before post-chlorination. Moreover, UV and UV/PS pre-treatments both enhanced the formation of all the HMs in the subsequent chlorination. PS pre-oxidation decreased the TCM formation during post-chlorination, but increased the yields of MCM, DCM and total HMs. UV pre-irradiation significantly increased the bromide utilization of HMs, whereas UV/PS pre-oxidation decreased the bromine incorporation and utilization of HMs from the chlorination of CAP in a low-bromide water. UV irradiation, PS oxidation, and UV/PS AOP can inactivate pathogens and degrade organic pollutants, but this benefit should be weighed against a potential risk of the increased halomethane formation from degraded organic pollutants with and without post-chlorination.

  9. Rapid intranasal delivery of chloramphenicol acetyltransferase in the active form to different brain regions as a model for enzyme therapy in the CNS.

    PubMed

    Appu, Abhilash P; Arun, Peethambaran; Krishnan, Jishnu K S; Moffett, John R; Namboodiri, Aryan M A

    2016-02-01

    The blood brain barrier (BBB) is critical for maintaining central nervous system (CNS) homeostasis by restricting entry of potentially toxic substances. However, the BBB is a major obstacle in the treatment of neurotoxicity and neurological disorders due to the restrictive nature of the barrier to many medications. Intranasal delivery of active enzymes to the brain has therapeutic potential for the treatment of numerous CNS enzyme deficiency disorders and CNS toxicity caused by chemical threat agents. The aim of this work is to provide a sensitive model system for analyzing the rapid delivery of active enzymes into various regions of the brain with therapeutic bioavailability. We tested intranasal delivery of chloramphenicol acetyltransferase (CAT), a relatively large (75kD) enzyme, in its active form into different regions of the brain. CAT was delivered intranasally to anaesthetized rats and enzyme activity was measured in different regions using a highly specific High Performance Thin Layer Chromatography (HP-TLC)-radiometry coupled assay. Active enzyme reached all examined areas of the brain within 15min (the earliest time point tested). In addition, the yield of enzyme activity in the brain was almost doubled in the brains of rats pre-treated with matrix metalloproteinase-9 (MMP-9). Intranasal administration of active enzymes in conjunction with MMP-9 to the CNS is both rapid and effective. The present results suggest that intranasal enzyme therapy is a promising method for counteracting CNS chemical threat poisoning, as well as for treating CNS enzyme deficiency disorders. Published by Elsevier B.V.

  10. Toxic effect and adaptation in Scenedesmus intermedius to anthropogenic chloramphenicol contamination: genetic versus physiological mechanisms to rapid acquisition of xenobiotic resistance.

    PubMed

    Sánchez-Fortún, S; Marvá, F; Rouco, M; Costas, E; López-Rodas, V

    2009-07-01

    Anthropogenic water pollution is producing a challenge to the survival of phytoplankton populations. From an ecological point of view, the tolerance of these microorganisms to water pollution is of paramount importance since they are the principal primary producers of aquatic ecosystems. The adaptation of a common chlorophyta species (Scenedesmus intermedius) exposed to selected dose-response chloramphenicol (CAP) concentrations has been analyzed. A fluctuation analysis demonstrated that CAP-resistant cells arise due to spontaneous mutation which occurs randomly prior to the antibiotic exposure. CAP-inhibited growth and photosynthetic performance of algal cells at 0.28 mg/l, and the IC(50(72)) value was established in 0.10 mg/l for both parameters. The mutation rate from CAP sensitivity to resistance was 1.01 x 10(-5) mutations per cell division, while the frequency of CAP-resistant allele in non-polluted environment was estimated to be 5.5 CAP-resistant mutants per 10(3) sensitive-cells. These results demonstrate that resistant mutants exhibit a diminished fitness until 5 mg/l of CAP, thus enabling the survival of microalgae population.

  11. In situ solvothermal growth of metal-organic framework-ionic liquid functionalized graphene nanocomposite for highly efficient enrichment of chloramphenicol and thiamphenicol.

    PubMed

    Wu, Mian; Ai, Youhong; Zeng, Baizhao; Zhao, Faqiong

    2016-01-04

    Here we report a facile in situ solvothermal growth method for immobilization of metal-organic framework-ionic liquid functionalized graphene (MOF-5/ILG) composite on etched stainless steel wire. The X-ray diffraction spectra, scanning electron microscopy and transmission electron microscopy images showed that the metal organic framework possessed good crystal shape and its structure was not disturbed by the introduction of ILG. Moreover, the covalent bond established between the amino group of ILG and the carboxylic group of the metal organic framework improved the mechanical stability and structure uniformity of the microcrystals. The obtained material combined the favorable attributes of both metal-organic framework and ILG, having high surface area (820 m(2)/g) and good adsorption capability. Its adsorption properties were explored by preconcentrating chloramphenicol and thiamphenicol from aqueous solutions prior to gas chromatography-flame ionization detection. The MOF-5/ILG exhibited high enrichment capacity for the analytes as they could interact through π-π and H-bonding interaction. Under the optimum conditions, good linearity (correlation coefficients higher than 0.9981), low limits of detection (14.8-19.5 ng/L), and good precision (relative standard deviations less than 6.0% (n=5)) were achieved. The MOF-5/ILG composite displayed durable property. The method was applied to the determination of two antibiotics in milk, honey, urine and serum samples with acceptable relative recoveries of 82.3-103.2%.

  12. Novel spectrophotometric determination of chloramphenicol and dexamethasone in the presence of non labeled interfering substances using univariate methods and multivariate regression model updating.

    PubMed

    Hegazy, Maha A; Lotfy, Hayam M; Rezk, Mamdouh R; Omran, Yasmin Rostom

    2015-04-05

    Smart and novel spectrophotometric and chemometric methods have been developed and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and dexamethasone sodium phosphate (DSP) in presence of interfering substances without prior separation. The first method depends upon derivative subtraction coupled with constant multiplication. The second one is ratio difference method at optimum wavelengths which were selected after applying derivative transformation method via multiplying by a decoding spectrum in order to cancel the contribution of non labeled interfering substances. The third method relies on partial least squares with regression model updating. They are so simple that they do not require any preliminary separation steps. Accuracy, precision and linearity ranges of these methods were determined. Moreover, specificity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied for analysis of both drugs in their pharmaceutical formulation. The obtained results have been statistically compared to that of an official spectrophotometric method to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision.

  13. Cloning, expression and purification of a sarcoplasmic calcium-binding protein from the sandworm Nereis diversicolor via a fusion product with chloramphenicol acetyltransferase.

    PubMed

    Dekeyzer, N; Engelborghs, Y; Volckaert, G

    1994-01-01

    A gene coding for the Nereis sarcoplasmic calcium-binding protein (NSCP) was synthesized and expressed in Escherichia coli. The sequence of the gene was derived from the protein sequence by reverse translation. It possesses a number of unique, regularly spaced, restriction endonuclease cleavage sites to facilitate future site-directed mutagenesis. For the cloning strategy the gene sequence was divided into four parts. Three parts were cloned by ligation of hybridized oligomers and one part by inverse PCR. The protein was expressed as a fusion protein with the bacterial chloramphenicol acetyl-transferase (CAT), which could be easily purified by affinity chromatography. At the junction of the CAT and NSCP moieties a recognition site for the proteolytic enzyme factor Xa was built in. However, the distance between the moieties appeared to be crucial to warrant cleavage. A kinetic analysis showed that NSCP prepared from the sandworm and the one expressed by E. coli behaved in the same way. This system provides a basis for site-specific mutagenesis studies, in order to elucidate the molecular mechanism of cation binding and concomitant conformational changes.

  14. Mechanistic studies of uncatalyzed and ruthenium(III)-catalyzed oxidation of the antibiotic drug chloramphenicol by hexacyanoferrate(III) in aqueous alkaline medium: a comparative kinetic study.

    PubMed

    Meti, M D; Byadagi, K S; Nandibewoor, S T; Chimatadar, S A

    The kinetics of oxidation of the antibiotic drug chloramphenicol (CHP) by hexacyanoferrate(III) (HCF) has been investigated spectrophotometrically both in the absence and presence of ruthenium(III) catalyst in aqueous alkaline medium at 25 °C and at constant ionic strength of 1.10 mol dm(-3). The stoichiometry is identical in both cases, i.e. [CHP]/[HCF] = 1:2. The oxidation products were identified by TLC and spectral studies such as GC-MS, IR, and (1)H NMR. In both catalyzed and uncatalyzed reactions, the order with respect to the concentration of HCF is unity, whereas the order with respect to the concentration of CHP and the concentration of OH(-) is less than unity over the concentration range studied. The order with respect to the concentration of Ru(III) is unity. The reaction in the presence of Ru(III) is approximately tenfold faster than the uncatalyzed reaction. The active species of oxidant and catalyst are [Fe(CN)6](3-) and [Ru(H2O)5(OH)](2+), respectively. On the basis of experimental results suitable mechanisms are proposed. The reaction constants involved in the different steps of the reaction mechanisms were calculated for both cases. The catalytic constant was also calculated for the catalyzed reaction at different temperatures. The activation parameters with respect to the slow step of the mechanism and thermodynamic quantities are also determined.

  15. Novel spectrophotometric determination of chloramphenicol and dexamethasone in the presence of non labeled interfering substances using univariate methods and multivariate regression model updating

    NASA Astrophysics Data System (ADS)

    Hegazy, Maha A.; Lotfy, Hayam M.; Rezk, Mamdouh R.; Omran, Yasmin Rostom

    2015-04-01

    Smart and novel spectrophotometric and chemometric methods have been developed and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and dexamethasone sodium phosphate (DSP) in presence of interfering substances without prior separation. The first method depends upon derivative subtraction coupled with constant multiplication. The second one is ratio difference method at optimum wavelengths which were selected after applying derivative transformation method via multiplying by a decoding spectrum in order to cancel the contribution of non labeled interfering substances. The third method relies on partial least squares with regression model updating. They are so simple that they do not require any preliminary separation steps. Accuracy, precision and linearity ranges of these methods were determined. Moreover, specificity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied for analysis of both drugs in their pharmaceutical formulation. The obtained results have been statistically compared to that of an official spectrophotometric method to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision.

  16. Monoclonal antibody-mediated clean-up procedure for the high-performance liquid chromatographic analysis of chloramphenicol in milk and eggs.

    PubMed

    van de Water, C; Tebbal, D; Haagsma, N

    1989-09-08

    A simple, rapid and specific sample preparation method based on antibody-mediated clean-up for the determination of chloramphenicol (CAP) in milk and eggs was developed. Skimmed milk and centrifuged egg homogenates were filtered and directly applied to immunoaffinity columns which were prepared by coupling monoclonal antibodies against CAP to a carbonyldiimidazole-activated support. Using a 0.2 M glycine, 0.5 M NaCl (pH 2.8) solution as an eluent, the immunoaffinity columns can be used more than 30 times without a decrease in column capacity. In subsequent high-performance liquid chromatographic analysis, no matrix interferences were observed. Good recoveries were obtained at spiking levels of 1-100 micrograms kg-1. Due to the high specificity of the clean-up procedure, the limit of detection can be lowered by increasing the test portion. Concerning milk, the limit of detection was successfully lowered to 20 ng kg-1 by increasing the test portion to 11 (recovery 99%). The method was applied to eggs produced by hens treated with CAP. The results are compared with those obtained by solid-phase extraction using silica gel.

  17. In vitro post-antibiotic effect of fluoroquinolones, macrolides, beta-lactams, tetracyclines, vancomycin, clindamycin, linezolid, chloramphenicol, quinupristin/dalfopristin and rifampicin on Bacillus anthracis.

    PubMed

    Athamna, A; Athamna, M; Medlej, B; Bast, D J; Rubinstein, E

    2004-04-01

    The aim of this study was to investigate in vitro the post-antibiotic effect (PAE) of 19 antibacterial agents against two strains of Bacillus anthracis (ST-1 and Sterne strains). PAE was determined by calculating the time required for the viable counts of antibiotic-exposed bacteria (at concentrations of 10x MIC and exposure for 2 h) at 37 degrees C to increase by 1 log10 above the counts observed immediately after antibiotic removal compared with the corresponding time for controls not exposed to antibiotics. The PAEs of the fluoroquinolones (ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin and garenoxacin) were 2-5 h. The macrolide (erythromycin, clarithromycin and telithromycin) PAEs were 1-4 h, and that of clindamycin was 2 h. The PAEs induced by tetracycline and minocycline were 1-3 h. The PAEs induced by the beta-lactams (penicillin G, amoxicillin and ceftriaxone), vancomycin, linezolid and chloramphenicol were 1-2 h. The PAE induced by rifampicin was 4-5 h. Quinupristin/dalfopristin had the longest PAE, lasting for 7-8 h. Our results indicate that the PAE is unrelated to the MIC but may be related to the rapidity of bacterial kill. These observations may bear importance on treatment regimens of human anthrax.

  18. Magnetic ionic liquid aqueous two-phase system coupled with high performance liquid chromatography: A rapid approach for determination of chloramphenicol in water environment.

    PubMed

    Yao, Tian; Yao, Shun

    2017-01-20

    A novel organic magnetic ionic liquid based on guanidinium cation was synthesized and characterized. A new method of magnetic ionic liquid aqueous two-phase system (MILATPs) coupled with high-performance liquid chromatography (HPLC) was established to preconcentrate and determine trace amount of chloramphenicol (CAP) in water environment for the first time. In the absence of volatile organic solvents, MILATPs not only has the excellent properties of rapid extraction, but also exhibits a response to an external magnetic field which can be applied to assist phase separation. The phase behavior of MILATPs was investigated and phase equilibrium data were correlated by Merchuk equation. Various influencing factors on CAP recovery were systematically investigated and optimized. Under the optimal conditions, the preconcentration factor was 147.2 with the precision values (RSD%) of 2.42% and 4.45% for intra-day (n=6) and inter-day (n=6), respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.14ngmL(-1) and 0.42ngmL(-1), respectively. Fine linear range of 12.25ngmL(-1)-2200ngmL(-1) was obtained. Finally, the validated method was successfully applied for the analysis of CAP in some environmental waters with the recoveries for the spiked samples in the acceptable range of 94.6%-99.72%. Hopefully, MILATPs is showing great potential to promote new development in the field of extraction, separation and pretreatment of various biochemical samples.

  19. Molybdenum disulfide nanosheets coated multiwalled carbon nanotubes composite for highly sensitive determination of chloramphenicol in food samples milk, honey and powdered milk.

    PubMed

    Govindasamy, Mani; Chen, Shen-Ming; Mani, Veerappan; Devasenathipathy, Rajkumar; Umamaheswari, Rajaji; Joseph Santhanaraj, K; Sathiyan, Anandaraj

    2017-01-01

    We have described a hybrid material that consists of molybdenum disulfide nanosheets (MoS2) coated on functionalized multiwalled carbon nanotubes (f-MWCNTs) for sensitive and selective determination of chloramphenicol (CAP). The MoS2/f-MWCNTs nanocomposite was successfully prepared through a hydrothermal process and its structure was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The MoS2/f-MWCNTs nanocomposite holds excellent electrochemical properties and it displays excellent electrocatalytic ability to CAP. Under optimized working conditions, the nanocomposite film modified electrode responds linearly to CAP in the concentration range of 0.08-1392μM. The detection limit was obtained as 0.015μM (±0.003). The electrode has high level of selectivity in presence of large excess concentrations of interfering species. In addition, the modified electrode offers satisfactory repeatability, reproducibility and stability. The practical applicability of the electrode was demonstrated in food samples such as, milk, powdered milk and honey samples and the recoveries are agreeable which clearly revealed its practical feasibility in food analysis. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Performance Assessment and Comparability of a Commercial Enzyme-Linked Immunosorbent Assay Kit with Liquid Chromatography-Tandem Mass Spectrometry for Chloramphenicol Residues in Crab and Shrimp.

    PubMed

    Jester, Edward L E; Loader, Jared I; El Said, Kathleen R; Abraham, Ann; Flores Quintana, Harold A; Plakas, Steven M

    2016-01-01

    Monitoring for chloramphenicol (CAP) in aquaculture products is primarily performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which requires expensive equipment and specialized training. Many laboratories prefer to screen samples with facile and high-throughput enzyme-linked immunosorbent assay (ELISA) kits for CAP residues before submitting samples for LC-MS/MS quantification and confirmation. We evaluated the performance of a Ridascreen (R-Biopharm) ELISA kit for CAP in spiked and incurred crab and shrimp muscle at levels bracketing the minimum required performance level for analysis (0.3 ng/g). The Ridascreen ELISA kit incorporates antibody directed against CAP. Incurred CAP levels in crab and shrimp muscle were verified using LC-MS/MS. We found good repeatability (relative standard deviation) of the ELISA in spiked and incurred crab and shrimp muscle samples, with values ranging from 6.8 to 21.7%. Recoveries of CAP from tissues spiked at 0.15 to 0.60 ng/g ranged from 102 to 107%. Minimal cross-reactivity with blank crab and shrimp muscle matrix components was observed. ELISA data were highly correlated with those of LC-MS/MS for CAP in incurred muscle tissue. We believe this study to be the first evaluation of the performance and comparability of a CAP ELISA kit and LC-MS/MS for determination of CAP residues, as well as their elimination, in crab muscle. Our findings support the use of this ELISA kit for screening purposes and, when used in conjunction with validated instrumental methods, for regulatory monitoring of CAP in these species.

  1. Chloramphenicol decreases CB1 receptor expression in the nucleus accumbens and prefrontal cortex and prevents amphetamine-induced conditioned place preference in rats.

    PubMed

    Amancio-Belmont, Octavio; Pérez-Vázquez, Diego; Ruiz-Contreras, Alejandra E; Pérez de la Mora, Miguel; Rueda-Orozco, Pavel E; Méndez-Díaz, Mónica; Prospero-Garcia, Oscar E

    2017-08-01

    Drug dependence seems to involve a learning and memory process. Since learning and memory depend on protein synthesis, drug dependence may depend on protein synthesis, too. Drug-induced reward is a crucial effect for the development of drug-dependence. We used chloramphenicol (CAP, a protein synthesis inhibitor), to evaluate its effects on amphetamine (amph)-seeking behavior, on CB1R expression and on protein synthesis in general, in specific areas of the brain. Two groups of Wistar adult male rats were subjected to amph-induced conditioned place preference (CPP). Rats in group 1 received amph and were kept in the chamber for 30min. Once this period elapsed, they received a subcutaneous injection of saline (veh) and were returned to their home-cage. Rats in group 2 were also treated with amph but received CAP (150mg/kgsc) instead of saline. Once CPP was evaluated rats were sacrificed and the prefrontal cortex (PFC), the nucleus accumbens (NAcc) and the hippocampus (Hipp) were isolated and prepared for CB1R Western blot analysis. A vivarium reared group of rats was added as a non-experimentally manipulated control group. Results indicate that group 1 developed CPP while increasing CB1R expression in the NAcc. Group 2 did not develop CPP, had lower CB1R expression in the PFC and lacked the CB1R increase in the NAcc observed in the amph+veh group. These results support the notion that among the underlying mechanisms for amph-seeking reward is an increase in CB1R, further supporting an interaction between dopamine/endocannabinoids in CPP learning. Copyright © 2017. Published by Elsevier Inc.

  2. Molecularly imprinted matrix solid-phase dispersion for extraction of chloramphenicol in fish tissues coupled with high-performance liquid chromatography determination.

    PubMed

    Guo, Linyuan; Guan, Min; Zhao, Chuande; Zhang, Haixia

    2008-12-01

    The synthesis and evaluation of a molecularly imprinted polymer (MIP) as a selective matrix solid-phase dispersion (MSPD) sorbent, coupled with high-performance liquid chromatography for the efficient determination of chloramphenicol (CAP) in fish tissues are studied. The polymer was prepared using CAP as the template molecule, vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer, and sodium dodecyl sulfate as the surfactant in the presence of water as a solvent by miniemulsion polymerization. The CAP-imprinted polymers and nonimprinted polymers (NIPs) were characterized by Fourier transform IR spectroscopy, scanning electron microscopy, and static adsorption experiments. The CAP-imprinted material prepared showed high adsorption capacity, significant selectivity, and good site accessibility. The maximum static adsorption capacity of the CAP-imprinted and the NIP material for CAP was 78.4 and 59.9 mg g(-1), respectively. The relative selectivity factors of this CAP-imprinted material were larger than 1.9. Several parameters influencing the MSPD process were optimized. Finally, the CAP-imprinted polymers were used as the sorbent in MSPD to determine CAP in three kinds of fishes and resulted in satisfactory recovery in the range 89.8-101.43%. CAP-imprinted polymer as a sorbent in MSPD is better than C18 and attapulgite in terms of both recovery and percent relative standard deviation. The baseline noise was measured from a chromatogram of a blank fish sample which was treated after the MSPD procedure using CAP-imprinted polymer as a sorbent. Signal values of 3 times the noise (signal-to-noise ratio of 3) and 10 times the noise (signal-to-noise ratio of 10) were used to calculate the limit of detection and the limit of quantitation of the calibration curve. The limit of detection for CAP was 1.2 ng g(-1) and the limit of quantitation was 3.9 ng g(-1).

  3. A human parvovirus, adeno-associated virus, as a eucaryotic vector: Transient expression and encapsidation of the procaryotic gene for chloramphenicol acetyltransferase

    SciTech Connect

    Tratschin, J.D.; West, M.H.P.; Sandbank, T.; Carter, B.J.

    1984-10-01

    The authors have used the defective human parvovirus adeno-associated virus (AAV) as a novel eurocaryotic vector (parvector) for the expression of a foreign gene in human cells. The recombinant, pAV2, contains the AAV genome in a pBR322-derived bacterial plasmid. When pAV2 is transfected into human cells together with helper adenovirus particles, the AAV genome is rescued from the recombinant plasmid and replicated to produce infectious AAV particles at high efficiency. To create a vector, we inserted a procaryotic sequence coding for chloramphenicol acetyltransferase (CAT) into derivatives of pAV2 following either of the AAV promoters p/sub 40/ (pAVHiCAT) and p/sub 19/ (pAVBcCAT). When transfected into human 293 cells or HeLa cells, pAVHiCAT expressed CAT activity in the absence of adenovirus. In the presence of adenovirus, this vector produced increased amounts of CAT activity and the recombinant AAV-CAT genome was replicated. In 293 cells, pAVBcCAT expressed a similar amount of CAT activity in the absence or presence of adenovirus and the recombinant AAV-CAT genome was not replicated. In HeLa cells, pAVBcCAT expressed low levels of CAT activity, but this level was elevated by coinfection with adenovirus particles or by cotransfection with a plasmid which expressed the adenovirus early region 1A (E1A) product. The E1A product is a transcriptional activator and is expressed in 293 cells. Thus, expression from two AAV promoters is differentially regulated: expression from p/sub 19/ is increased by E1A, whereas p/sub 40/ yields high levels of constitutive expression in the absence of E1A. Both AAV vectors were packaged into AAV particles by complementation with wild-type AAV and yielded CAT activity when subsequently infected into cells in the presence of adenovirus.

  4. Rapid intranasal delivery of chloramphenicol acetyltransferase in the active form to different brain regions as a model for enzyme therapy in the CNS

    PubMed Central

    Appu, Abhilash P; Arun, Peethambaran; Krishnan, Jishnu K. S.; Moffett, John R.; Namboodiri, Aryan M. A.

    2015-01-01

    Background The blood brain barrier (BBB) is critical for maintaining central nervous system (CNS) homeostasis by restricting entry of potentially toxic substances. However, the BBB is a major obstacle in the treatment of neurotoxicity and neurological disorders due to the restrictive nature of the barrier to many medications. Intranasal delivery of active enzymes to the brain has therapeutic potential for the treatment of numerous CNS enzyme deficiency disorders and CNS toxicity caused by chemical threat agents. New method The aim of this work is to provide a sensitive model system for analyzing the rapid delivery of active enzymes into various regions of the brain with therapeutic bioavailability. Results We tested intranasal delivery of chloramphenicol acetyltransferase (CAT), a relatively large (75 kD) enzyme, in its active form into different regions of the brain. CAT was delivered intranasally to anaesthetized rats and enzyme activity was measured in different regions using a highly specific High Performance Thin Layer Chromatography (HP-TLC)-radiometry coupled assay. Active enzyme reached all examined areas of the brain within 15 min (the earliest time point tested). In addition, the yield of enzyme activity in the brain was almost doubled in the brains of rats pre-treated with matrix metalloproteinase-9 (MMP-9). Comparison with existing method (s) Intranasal administration of active enzymes in conjunction with MMP-9 to the CNS is both rapid and effective. Conclusion The present results suggest that intranasal enzyme therapy is a promising method for counteracting CNS chemical threat poisoning, as well as for treating CNS enzyme deficiency disorders. PMID:26688469

  5. Isolation and characterization of cyclo-(tryptophanyl-prolyl) and chloramphenicol from Streptomyces sp. SUK 25 with antimethicillin-resistant Staphylococcus aureus activity

    PubMed Central

    Alshaibani, Muhanna M; Jalil, Juriyati; Sidik, Nik M; Edrada-Ebel, Ruangelie; Zin, Noraziah M

    2016-01-01

    Background Zingiber spectabile, commonly known as Beehive Ginger, is used as an ethnobotanical plant in many countries as an appetizer or to treat stomachache, toothache, muscle sprain, and as a cure for swelling, sores and cuts. This is the first report of isolation of Streptomyces strain from the root of this plant. Strain Universiti Kebangsaan 25 (SUK 25) has a very high activity to produce secondary metabolites against methicillin-resistant Staphylococcus aureus (MRSA), which is associated with high morbidity and mortality rates due to acquired multidrug resistance genes and causes medication failure in some clinical cases worldwide. Phylogenetic analysis based on the 16S ribosomal RNA gene sequence exhibited that the most closely related strain was Streptomyces omiyaensis NBRC 13449T (99.0% similarity). Aim This study was conducted to carry out the extraction, identification, and biological evaluation of active metabolites isolated from SUK 25 against three MRSA strains, namely, MRSA ATCC 43300, MRSA ATCC 33591, and MRSA ATCC 49476. Materials and methods The production of secondary metabolites by this strain was optimized through Thronton’s media. Isolation, purification, and identification of the bioactive compounds were carried out using reversed-phase high-performance liquid chromatography, high-resolution mass spectrometry, Fourier transform infrared, and one-dimensional and two-dimensional nuclear magnetic resonance. Results During screening procedure, SUK 25 exhibited good antimicrobial potential against several strains of MRSA. The best biological activity was shown from fraction number VII and its subfractions F2 and F3 with minimum inhibitory concentration values at 16 µg/mL and 8 µg/mL, respectively. These two subfractions were identified as diketopiperazine cyclo-(tryptophanyl-prolyl) and chloramphenicol. Conclusion On the basis of obtained results, SUK 25 isolated from Z. spectabile can be regarded as a new valuable source to produce secondary

  6. An aptamer-based effective method for highly sensitive detection of chloramphenicol residues in animal-sourced food using real-time fluorescent quantitative PCR.

    PubMed

    Duan, Ye; Wang, Lihui; Gao, Zhiqiang; Wang, Huishan; Zhang, Hexiao; Li, Hao

    2017-04-01

    Chloramphenicol (CAP) residues can not only harm human health through entering food chain, but also cause the spreading of drug-resistant bacteria, thereby leading to secondary environmental pollution. Therefore, it is in urgent need of establishing an efficient technology to detect CAP residues in animal-sourced food. In this study, a novel sensitive approach for detection of CAP was designed based on a CAP specific aptamer and real-time fluorescent quantitative PCR (qRT-PCR). The CAP specific aptamer was firstly hybridized with a biotin modified complementary probe, and then was immobilized on streptavidin conjugated magnetic beads through biotin. When CAP was added, the aptamer would specifically bind with CAP by forming a hairpin structure and be released from the magnetic beads for CAP detection by qRT-PCR. Factors (i.e., probe strand length, aptamer concentration, NaCl concentration and incubation time) that would influence the determination accuracy of this aptamer-based detection system were optimized. Under the optimized conditions, the present detection system exhibited a high sensitivity toward CAP with a limit of detection of 0.1ng/mL (linear range from 0.1 to 20ng/mL). Moreover, this detection system also showed high selectivity against thiamphenicol (TAP) and florfenicol (FF), which are CAP's structure analogs. Eventually, this detection system was applied for detecting CAP in real spiked milk. The recovery rate of CAP from spiked milk samples ranged from 94.0-102.0%. These results indicated this developed detection system a promising high sensitive and specific method of CAP residues detection in animal-sourced food. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A "signal-on'' aptasensor for simultaneous detection of chloramphenicol and polychlorinated biphenyls using multi-metal ions encoded nanospherical brushes as tracers.

    PubMed

    Yan, Zhongdan; Gan, Ning; Wang, De; Cao, Yuting; Chen, Meng; Li, Tianhua; Chen, Yinji

    2015-12-15

    A "signal-on'' aptasensor was developed for simultaneous detection of chloramphenicols (CAP) and polychlorinated biphenyl-72 (PCB72) with a novel multi-metal ions encoded nanospherical brushes as nanotracers. To construct the assay, the respective aptamer of CAP and PCB72 labeled magnetic gold nanoparticles as capture probes (aptamer-MGPs), and their complementary single strand DNA (s-DNA) encoded metal ions (Cd(2+) and Pb(2+)) on nanospherical branched polyethylene imine brushes as tracers (s-DNA-MSPEIs), were simultaneously synthesized. After that, the capture probe and tracers were connected through a hybridization reaction between s-DNA and aptamers. In the presence of CAP and PCB72, the analytes could react with the aptamers on capture probes and release the tracers into supernatant after magnetic separation. The released tracers with metal ions (Cd(2+) and Pb(2+)) could be simultaneously detected through the square wave voltammetry (SWV) without acid dissolution, which can switch the signals of the biosensor to "on'' state. Under optimal conditions, the assay could detect CAP and PCB72 as low as 0.3 pg mL(-1) with the dynamitic range from 0.001 to 100 ng mL(-1) and exhibited excellent selectivity. More importantly, the strategy can be extended easily to other targets after changing the corresponding aptamers and other metal ions tracers, which provides a promising and facile approach in multiplex detection of ultra-trace level of pollutants in food safety without more complex separation and washing steps. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Randomised equivalency trial comparing 2.5% povidone‐iodine eye drops and ophthalmic chloramphenicol for preventing neonatal conjunctivitis in a trachoma endemic area in southern Mexico

    PubMed Central

    Ramirez‐Ortiz, Marco A; Rodriguez‐Almaraz, Manuel; Ochoa‐DiazLopez, Héctor; Diaz‐Prieto, Paulina; Rodriguez‐Suárez, Romeo S

    2007-01-01

    Aim To evaluate the effectiveness of 2.5% povidone‐iodine eye drops (PIED) compared with ophthalmic chloramphenicol (OC) for preventing neonatal conjunctivitis. Methods 2004 neonates were enrolled from three rural hospitals in a trachoma endemic area. They were randomly assigned to receive either PIED (n = 1024) or OC (n = 974). Infectious conjunctivitis was confirmed by laboratory methods, including specific search for Chlamydia trachomatis by polymerase chain reaction assay. Results During the first 48 hours after birth, PIED and OC had similar efficacy against bacterial conjunctivitis (95% confidence interval (CI), −0.031 to −0.004; p = 0.01); from day 3 to day 15, PIED was 6% less effective than OC (95% CI, −0.058 to −0.006; p = 0.01); after day 16 there was no significant difference between the groups (95% CI, −0.022 to 0.041; p = 0.57). However, the risk of C trachomatis conjunctivitis was increased in neonates receiving PIED prophylaxis (relative risk = 1.99 (95% CI, 1.07 to 3.71), log‐rank p = 0.029). Ocular side effects were rare and self limiting in both groups (p = 0.223). Conclusions PIED seems to increase the risk of acquiring chlamydial conjunctivitis in neonates. Additional measures are required to prevent mother to fetus transmission of chlamydial infection during pregnancy, delivery, and after birth. PMID:17947266

  9. Immunoaffinity column cleanup with LC/MS/MS for the determination of chloramphenicol in honey and prawns: single-laboratory validation.

    PubMed

    Mackie, Jennifer; Marley, Elaine; Donnelly, Carol

    2013-01-01

    A single-laboratory validation was conducted to establish the effectiveness of an immunoaffinity column (IAC) cleanup procedure followed by LC/MS/MS for the determination of chloramphenicol (CAP) in honey and prawns. Honey is dissolved in buffer solution and centrifuged, and an aliquot applied to an IAC. For prawns, a portion of the homogenized sample is shaken with buffer and centrifuged, and an aliquot similarly applied to an IAC. For both matrix extracts, CAP is removed from the IAC with neat methanol, then directly analyzed by electrospray LC/MS/MS in the negative ionization mode using m/z 321 as a precursor ion and m/z 257 and 152 as qualifier and quantifier ions, respectively. Test portions of blank honey and prawns were fortified with CAP to give levels of 0.3, 1.0, and 5.0 microg/kg. Recoveries of CAP on 3 consecutive days ranged from 83-103% for honey and 84-108% for prawns. Based on results for fortified blank matrixes (triplicate at three levels), the RSD for repeatability (RSDr) averaged 8.4% for honey and 4.8% for prawns. The method LOD was 0.05 for prawns and 0.16 microg/kg for honey, both well below the minimum required method performance limit for CAP. The accuracy of the method was demonstrated by participation in proficiency testing, where satisfactory Z-scores were obtained for CAP in incurred samples of both honey and prawns. The method was shown to be applicable to a wide range of other matrixes, including milk, egg, royal jelly, meat, and seafood products.

  10. Food Safety is an Important Public Health Issue: Chloramphenicol Residues Determination by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) in honey.

    PubMed

    Krivohlavek, Adela; Žuntar, Irena; Ivešić, Martina; Andačić, Ivana Mandić; Šikić, Sandra

    2014-12-01

    Honey is used for nutritional, medicinal and industrial purposes and antibiotic residues may harm its quality and constitute a danger to human health. The broad spectrum antibiotic chloramphenicol (CAP) was used for curative purposes in veterinary medicine, but is now forbidden in European Union (EU) because of its many serious side effects (e.g. aplastic anaemia, grey syndrome, severe bone marrow depression and hypersensitivity). The aim of this study was to facilitate analyses of the quality and safety of Croatian honey distributed to whole European Union market; an assessment that has not previously been made. CAP in honey was qualifying and quantifying by validated liquid chromatography tandem mass spectrometry with negative electrospray ionisation method (LC-MS/MS). The target antibiotic was separated on chromatographic column Zorbax SB C18 (150 mm x 2.1 mm, 3.5 μm) with a gradient elution using acetonitrile - 0.1% formic acid mobile phase at a flow rate of 0.3 mL/min, with column temperature 35°C for CAP and 5D-CAP as internal standard. Homogenised honey samples were diluted with acetate buffer solution and extracted on Oasis Hydrophilic-Lipophilic-Balanced (HLB) sorbents. The method was used to analyse 280 domestic honey samples collected throughout Croatia between 2005.-2013. Recoveries of the method for real (acacia, chestnut, linden and flower) honey samples were 102% with RSD 8.4%. The value CCα and CCβ were 0.09 and 0.12 μg/kg, respectively. Results showed only three subsequent positive detections (1.1%) of CAP in honey. Analysed honey samples from Croatia showed good quality and safety what is the one of the main objective in consumer health policy in EU.

  11. The gene cluster for chloramphenicol biosynthesis in Streptomyces venezuelae ISP5230 includes novel shikimate pathway homologues and a monomodular non-ribosomal peptide synthetase gene.

    PubMed

    He, J; Magarvey, N; Piraee, M; Vining, L C

    2001-10-01

    Regions of the Streptomyces venezuelae ISP5230 chromosome flanking pabAB, an amino-deoxychorismate synthase gene needed for chloramphenicol (Cm) production, were examined for involvement in biosynthesis of the antibiotic. Three of four ORFs in the sequence downstream of pabAB resembled genes involved in the shikimate pathway. BLASTX searches of GenBank showed that the deduced amino acid sequences of ORF3 and ORF4 were similar to proteins encoded by monofunctional genes for chorismate mutase and prephenate dehydrogenase, respectively, while the sequence of the ORF5 product resembled deoxy-arabino-heptulosonate-7-phosphate (DAHP) synthase, the enzyme that initiates the shikimate pathway. A relationship to Cm biosynthesis was indicated by sequence similarities between the ORF6 product and membrane proteins associated with Cm export. BLASTX searches of GenBank for matches with the translated sequence of ORF1 in chromosomal DNA immediately upstream of pabAB did not detect products relevant to Cm biosynthesis. However, the presence of Cm biosynthesis genes in a 7.5 kb segment of the chromosome beyond ORF1 was inferred when conjugal transfer of the DNA into a blocked S. venezuelae mutant restored Cm production. Deletions in the 7.5 kb segment of the wild-type chromosome eliminated Cm production, confirming the presence of Cm biosynthesis genes in this region. Sequencing and analysis located five ORFs, one of which (ORF8) was deduced from BLAST searches of GenBank, and from characteristic motifs detected in alignments of its deduced amino acid sequence, to be a monomodular nonribosomal peptide synthetase. GenBank searches did not identify ORF7, but matched the translated sequences of ORFs 9, 10 and 11 with short-chain ketoreductases, the ATP-binding cassettes of ABC transporters, and coenzyme A ligases, respectively. As has been shown for ORF2, disrupting ORF3, ORF7, ORF8 or ORF9 blocked Cm production.

  12. p-Aminobenzoic acid and chloramphenicol biosynthesis in Streptomyces venezuelae: gene sets for a key enzyme, 4-amino-4-deoxychorismate synthase.

    PubMed

    Chang, Z; Sun, Y; He, J; Vining, L C

    2001-08-01

    Amplification of sequences from Streptomyces venezuelae ISP5230 genomic DNA using PCR with primers based on conserved prokaryotic pabB sequences gave two main products. One matched pabAB, a locus previously identified in S. venezuelae. The second closely resembled the conserved pabB sequence consensus and hybridized with a 3.8 kb NcoI fragment of S. venezuelae ISP5230 genomic DNA. Cloning and sequence analysis of the 3.8 kb fragment detected three ORFs, and their deduced amino acid sequences were used in BLAST searches of the GenBank database. The ORF1 product was similar to PabB in other bacteria and to the PabB domain encoded by S. venezuelae pabAB. The ORF2 product resembled PabA of other bacteria. ORF3 was incomplete; its deduced partial amino acid sequence placed it in the MocR group of GntR-type transcriptional regulators. Introducing vectors containing the 3.8 kb NcoI fragment of S. venezuelae DNA into pabA and pabB mutants of Escherichia coli, or into the Streptomyces lividans pab mutant JG10, enhanced sulfanilamide resistance in the host strains. The increased resistance was attributed to expression of the pair of discrete translationally coupled p-aminobenzoic acid biosynthesis genes (designated pabB/pabA) cloned in the 3.8 kb fragment. These represent a second set of genes encoding 4-amino-4-deoxychorismate synthase in S. venezuelae ISP5230. In contrast to the fused pabAB set previously isolated from this species, they do not participate in chloramphenicol biosynthesis, but like pabAB they can be disrupted without affecting growth on minimal medium. The gene disruption results suggest that S. venezuelae may have a third set of genes encoding PABA synthase.

  13. Nucleotide sequences of genes encoding the type II chloramphenicol acetyltransferases of Escherichia coli and Haemophilus influenzae, which are sensitive to inhibition by thiol-reactive reagents.

    PubMed Central

    Murray, I A; Martinez-Suarez, J V; Close, T J; Shaw, W V

    1990-01-01

    Sensitivity of enzymes to inhibition by thiol-reactive reagents is often presented as evidence for the possible involvement of cysteine residues in substrate binding and catalysis or to highlight possible important differences in structure and mechanism between closely related enzymes. The primary phenotypic distinction between the enterobacterial type II chloramphenicol acetyltransferase (CATII; typified by the enzyme encoded by the incW transmissible plasmid pSa) and the CATI and CATIII variants is the greatly enhanced susceptibility of CATII to inactivation by thiol-specific modifying reagents. Determination of the nucleotide sequence of the gene, catII, present on pSa and that of a related determinant, catIIH, isolated from Haemophilus influenzae indicates that sensitivity to such reagents cannot be due to the presence of additional reactive cysteine residues in CATII. Comparative analysis of the inactivation of CATII and CATIII by 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), 4,4'-dithiodipyridine (DTDP) and methyl methanethiosulphonate (MMTS) suggests that (i) inactivation occurs as a result of chemical modification of the same residue (Cys-31) in each enzyme, (ii) reagents that inactivate via a pseudo-first-order process (DTNB and DTDP) appear to bind with a greater affinity to CATII, and (iii) the intrinsic reactivity of Cys-31 in CATII greatly exceeds that of the corresponding residue in CATIII. The results lead to the conclusion that a striking difference in chemical reactivity of a unique and conserved thiol group between closely related enzyme variants may not be easily explained even when a high-resolution tertiary structure is available for one of them. Plausible explanations include more favourable access of reagents to Cys-31 in CATII or an enhanced reactivity of its thiol group imposed by the side chains of residues that are not in immediate contact with it. PMID:2268278

  14. A Study of Electrocatalytic and Photocatalytic Activity of Cerium Molybdate Nanocubes Decorated Graphene Oxide for the Sensing and Degradation of Antibiotic Drug Chloramphenicol.

    PubMed

    Karthik, Raj; Vinoth Kumar, Jeyaraj; Chen, Shen-Ming; Karuppiah, Chelladurai; Cheng, Yi-Hui; Muthuraj, Velluchamy

    2017-02-22

    In this present work, "killing two birds with one stone" strategy was performed for the electrochemical trace level detection and photocatalytic degradation of antibiotic drug chloramphenicol (CAP) using Ce(MoO4)2 nanocubes/graphene oxide (CeM/GO) composite for the first time. The CeM/GO composite was synthesized via simple hydrothermal treatment followed by sonication process. The successful formation of CeM/GO composite was confirmed by several analytical and spectroscopic techniques. The CeM/GO composite modified glassy carbon electrode (GCE) showed excellent electrocatalytic activity toward the reduction of CAP in terms of decrease the potential and increase the cathodic peak current in comparison with different modified and unmodified electrodes. The electrocatalytic reduction of CAP based on the CeM/GO modified GCE exhibited high selectivity, wide linear ranges, lower detection limit, and good sensitivity of 0.012-20 and 26-272 μM, 2 nM ,and 1.8085 μA μM(-1) cm(-2), respectively. Besides, when CeM/GO/GCE was used to analyze the CAP in real samples, such as honey and milk, the satisfactory recovery results were obtained. On the other hand, the CeM/GO composite played excellent catalyst toward the photodegradation of CAP. The obtained results from the UV-vis spectroscopy clearly suggested that CeM/GO composite had high photocatalytic activity compared to pristine Ce(MoO4)2 nanocubes. The degradation efficiency of CeM/GO toward CAP is observed about 99% within 50 min under visible irradiation and it shows a good stability by observing the reusability of the catalyst. The enhanced photocatalytic performance was attributed to the increased migration efficiency of photoinduced electrons and holes.

  15. A homogeneous and "off-on" fluorescence aptamer-based assay for chloramphenicol using vesicle quantum dot-gold colloid composite probes.

    PubMed

    Miao, Yang-Bao; Ren, Hong-Xia; Gan, Ning; Zhou, You; Cao, Yuting; Li, Tianhua; Chen, Yinji

    2016-07-27

    In this work, a novel homogeneous and signal "off-on" aptamer based fluorescence assay was successfully developed to detect chloramphenicol (CAP) residues in food based on the fluorescence resonance energy transfer (FRET). The vesicle nanotracer was prepared through labeling single stranded DNA binding protein (SSB) on limposome-CdSe/ZnS quantum dot (SSB/L-QD) complexes. It was worth mentioning that the signal tracer (SSB/L-QD) with vesicle shape, which was fabricated being encapsulated with a number of quantum dots and SSB. The nanotracer has excellent signal amplification effects. The vesicle composite probe was formed by combining aptamer labeled nano-gold (Au-Apt) and SSB/L-QD. Which based on SSB's specific affinity towards aptamer. This probe can't emit fluoresce which is in "off" state because the signal from SSB/L-QD as donor can be quenched by the Au-aptas acceptor. When CAP was added in the composite probe solution, the aptamer on the Au-Apt can be preferentially bounded with CAP then release from the composite probe, which can turn the "off" signal of SSB/L-QD tracer into "on" state. The assay indicates excellent linear response to CAP from 0.001 nM to 10 nM and detection limit down to 0.3 pM. The vesicle probes with size of 88 nm have strong signal amplification. Because a larger number of QDs can be labeled inside the double phosphorus lipid membrane. Besides, it was employed to detect CAP residues in the milk samples with results being agreed well with those from ELISA, verifying its accuracy and reliability.

  16. Aminoacyl and peptidyl analogs of chloramphenicol as slow-binding inhibitors of ribosomal peptidyltransferase: a new approach for evaluating their potency.

    PubMed

    Michelinaki, M; Mamos, P; Coutsogeorgopoulos, C; Kalpaxis, D L

    1997-01-01

    In a model system derived from Escherichia coli, acetylphenylalanyl-puromycin is produced in a pseudo-first-order reaction between the preformed acetylphenylalanyl/tRNA/poly(U)/ribosome complex (complex C) and excess puromycin. Two aminoacyl analogs [3, Gly-chloramphenicol (CAM): 4, L-Phe-CAM] and two peptidyl analogs (2, L-Phe-Gly-CAM: 5, Gly-Phe-CAM) of CAM (1) were tested as inhibitors in this reaction. Detailed kinetic analysis suggests that these analogs (I) react competitively with complex C and form the complex C*l, which is inactive toward puromycin. C*l is formed via a two-step mechanism in which C*l is the product of a slow conformational change of the initial encounter complex Cl according to the equation C + l reversible Cl reversible C*l. Furthermore, we provide evidence that analog 5 may react further with C*l forming the species C*l2. The values of the apparent association rate constant (K(assoc)) are 1.42 x microM-1 min-1 for 2, 0.55 x microM-1 min-1 for 3, and 0.18 x microM-1 min-1 for 4 and 0.038 x microM-1 min-1 for 5 [corrected]. In the case of analog 5, K(assoc) is a linear function of the inhibitor concentration; when [I] approaches zero, the K(assoc) value is equal to 3.8 x 10(2) M-1 sec-1. Such values allow the classification of CAM analogs as slow-binding inhibitors. According to K(assoc) values, we could surmise that analog 2 is 2.5-fold more potent than 3 and 8-fold more potent than 4. The relative potency of analog 5 is the lowest among the analogs and is dependent on its concentration. The results are compared with previous data and discussed on the basis of a possible retro-inverso relationship between CAM analogs and puromycin.

  17. Impact of persulfate and ultraviolet light activated persulfate pre-oxidation on the formation of trihalomethanes, haloacetonitriles and halonitromethanes from the chlor(am)ination of three antibiotic chloramphenicols.

    PubMed

    Chu, Wenhai; Chu, Tengfei; Bond, Tom; Du, Erdeng; Guo, Yingqing; Gao, Naiyun

    2016-04-15

    Persulfate oxidation processes, with and without activation using ultraviolet light (respectively UV/PS and PS) have the potential to degrade anthropogenic chemicals in water. However, little is known about the impact of PS or UV/PS pre-oxidation on downstream formation of disinfection by-products (DBPs). In this study the three antibiotic chloramphenicols (chloramphenicol and two of its analogues [thiamphenicol and florfenicol], referred to collectively as CAPs), which frequently occur in wastewater-impacted source waters used by drinking water treatment plants, were selected as model antibiotic compounds. The formation of carbonaceous and nitrogenous disinfection by-products, including halomethanes, haloacetonitriles and halonitromethanes, during chlorination and chloramination preceded by PS and UV/PS was investigated. No significant concentrations of haloacetonitriles and halonitromethanes were detected during chlorination. During chloramination chloramphenicol formed a considerable amount of dichloronitromethane (e.g., 3.44 ± 0.33% mol/mol at NH2Cl dose = 1 mM) and trichloronitromethane (e.g., 0.79 ± 0.07% mol/mol at NH2Cl dose = 1 mM), compared with THM and HAN formation. PS pre-oxidation achieved a statistically significant reduction in trichloromethane formation from chlorination, and in HAN and HNM formation from chloramination. Although UV/PS slightly increased dichloroacetonitrile formation during chloramination, it significantly decreased dichloronitromethane and trichloronitromethane formation during chloramination. Overall, the use of PS and UV/PS has the potential to have contrasting impacts on DBP formation in heavily wastewater-impacted waters, depending on the disinfection method. Hence, their application needs to be carefully balanced against the downstream effect on DBP formation.

  18. Development of a Double Nuclear Gene-Targeting Method by Two-Step Transformation Based on a Newly Established Chloramphenicol-Selection System in the Red Alga Cyanidioschyzon merolae.

    PubMed

    Fujiwara, Takayuki; Ohnuma, Mio; Kuroiwa, Tsuneyoshi; Ohbayashi, Ryudo; Hirooka, Shunsuke; Miyagishima, Shin-Ya

    2017-01-01

    The unicellular red alga Cyanidioschyzon merolae possesses a simple cellular architecture that consists of one mitochondrion, one chloroplast, one peroxisome, one Golgi apparatus, and several lysosomes. The nuclear genome content is also simple, with very little genetic redundancy (16.5 Mbp, 4,775 genes). In addition, molecular genetic tools such as gene targeting and inducible gene expression systems have been recently developed. These cytological features and genetic tractability have facilitated various omics analyses. However, only a single transformation selection marker URA has been made available and thus the application of genetic modification has been limited. Here, we report the development of a nuclear targeting method by using chloramphenicol and the chloramphenicol acetyltransferase (CAT) gene. In addition, we found that at least 200-bp homologous arms are required and 500-bp arms are sufficient for a targeted single-copy insertion of the CAT selection marker into the nuclear genome. By means of a combination of the URA and CAT transformation systems, we succeeded in producing a C. merolae strain that expresses HA-cyclin 1 and FLAG-CDKA from the chromosomal CYC1 and CDKA loci, respectively. These methods of multiple nuclear targeting will facilitate genetic manipulation of C. merolae.

  19. Development of a Double Nuclear Gene-Targeting Method by Two-Step Transformation Based on a Newly Established Chloramphenicol-Selection System in the Red Alga Cyanidioschyzon merolae

    PubMed Central

    Fujiwara, Takayuki; Ohnuma, Mio; Kuroiwa, Tsuneyoshi; Ohbayashi, Ryudo; Hirooka, Shunsuke; Miyagishima, Shin-Ya

    2017-01-01

    The unicellular red alga Cyanidioschyzon merolae possesses a simple cellular architecture that consists of one mitochondrion, one chloroplast, one peroxisome, one Golgi apparatus, and several lysosomes. The nuclear genome content is also simple, with very little genetic redundancy (16.5 Mbp, 4,775 genes). In addition, molecular genetic tools such as gene targeting and inducible gene expression systems have been recently developed. These cytological features and genetic tractability have facilitated various omics analyses. However, only a single transformation selection marker URA has been made available and thus the application of genetic modification has been limited. Here, we report the development of a nuclear targeting method by using chloramphenicol and the chloramphenicol acetyltransferase (CAT) gene. In addition, we found that at least 200-bp homologous arms are required and 500-bp arms are sufficient for a targeted single-copy insertion of the CAT selection marker into the nuclear genome. By means of a combination of the URA and CAT transformation systems, we succeeded in producing a C. merolae strain that expresses HA-cyclin 1 and FLAG-CDKA from the chromosomal CYC1 and CDKA loci, respectively. These methods of multiple nuclear targeting will facilitate genetic manipulation of C. merolae. PMID:28352279

  20. Multi-class method for the determination of nitroimidazoles, nitrofurans, and chloramphenicol in chicken muscle and egg by dispersive-solid phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Zhiwen; Wu, Yuping; Li, Xiaowei; Wang, Yingyu; Li, Hui; Fu, Qin; Shan, Yawen; Liu, Tianhe; Xia, Xi

    2017-02-15

    This study describes the development of a multiresidue method for the efficient identification and quantification of nitroimidazoles, nitrofurans, and chloramphenicol in chicken and egg. After derivatization of nitrofuran metabolites, dispersive-solid phase extraction was used for the extraction of target analytes. An optimization strategy involved the selection of sorbents and extraction solutions for dispersive-solid phase extraction in order to achieve acceptably high recoveries and reduce co-extractives in the final extracts. Analytes were determined by ultra-high performance liquid chromatography-tandem mass spectrometry, in one single injection with a chromatographic run time of 7.5min. Mean recoveries ranged from 86.4% to 116.7% and interday precision was lower than 18%. The limits of quantification were between 0.1 and 0.5μg/kg, which were satisfactory to support surveillance monitoring. Finally, the method was applied to real samples, and metabolite of furazolidone, metronidazole and its metabolite, dimetridazole and its metabolite were detected in both chicken and egg samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Determination of chloramphenicol, thiamphenicol and florfenicol in milk and honey using modified QuEChERS extraction coupled with polymeric monolith-based capillary liquid chromatography tandem mass spectrometry.

    PubMed

    Liu, Hsiang-Yu; Lin, Shu-Ling; Fuh, Ming-Ren

    2016-04-01

    A poly(lauryl methacrylate-co-methacrylic acid-co-ethylene glycol dimethacrylate) [LMA-MAA-EDMA] monolithic column was used to simultaneously determine amphenicol antibiotics (chloramphenicol/CAP, thiamphenicol/TAP, and florfenicol/FF) in milk and honey samples by capillary liquid chromatography tandem mass spectrometry (LC-MS/MS). QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was optimized for sample pretreatment. Good linearity (0.1-15 ng g(-1)) and extraction recoveries (95.8-100.2% and 95.6-99.3% for milk and honey samples, respectively; n=3) with minor matrix effect (≦ 5% ion suppression) were obtained. Limits of detection were estimated at 0.02-0.045 ng g(-1). Good intra-day/inter-day precision (0.2-9.1%/0.3-8.7%) and accuracy (90.5-110.0%/93.4-109.3%) were achieved. With more than 200 analyses of real samples, no noticeable carry-over and deterioration of separation efficiency were observed using the monolithic column. The applicability of the developed QuEChERS-capillary LC-MS/MS method was demonstrated by determining the occurrence of CAP, TAP, and FF in various milk and honey samples.

  2. A novel "dual-potential" electrochemiluminescence aptasensor array using CdS quantum dots and luminol-gold nanoparticles as labels for simultaneous detection of malachite green and chloramphenicol.

    PubMed

    Feng, Xiaobin; Gan, Ning; Zhang, Huairong; Yan, Qing; Li, Tianhua; Cao, Yuting; Hu, Futao; Yu, Hongwei; Jiang, Qianli

    2015-12-15

    A novel type of "dual-potential" electrochemiluminescence (ECL) aptasensor array was fabricated on a homemade screen-printed carbon electrode (SPCE) for simultaneous detection of malachite green (MG) and chloramphenicol (CAP) in one single assay. The SPCE substrate consisted of a common Ag/AgCl reference electrode, carbon counter electrode and two carbon working electrodes (WE1 and WE2). In the system, CdS quantum dots (QDs) were modified on WE1 as cathode ECL emitters and luminol-gold nanoparticles (L-Au NPs) were modified on WE2 as anode ECL emitters. Then the MG aptamer complementary strand (MG cDNA) and CAP aptamer complementary strand (CAP cDNA) were attached on CdS QDs and L-Au NPs, respectively. The cDNA would hybridize with corresponding aptamer that was respectively tagged with cyanine dye (Cy5) (as quenchers of CdS QDs) and chlorogenic acid (CA) (as quenchers of l-Au NPs) using poly(ethylenimine) (PEI) as a bridging agent. PEI could lead to a large number of quenchers on the aptamer, which increased the quenching efficiency. Upon MG and CAP adding, the targets could induce strand release due to the highly affinity of analytes toward aptamers. Meanwhile, it could release the Cy5 and CA, which recovered cathode ECL of CdS QDs and anode ECL of L-Au NPs simultaneously. This "dual-potential" ECL strategy could be used to detect MG and CAP with the linear ranges of 0.1-100 nM and 0.2-150 nM, with detection limits of 0.03 nM and 0.07 nM (at 3sB), respectively. More importantly, this designed method was successfully applied to determine MG and CAP in real fish samples and held great potential in the food analysis.

  3. Cross-resistance to fluoroquinolones in multiple-antibiotic-resistant (Mar) Escherichia coli selected by tetracycline or chloramphenicol: decreased drug accumulation associated with membrane changes in addition to OmpF reduction.

    PubMed Central

    Cohen, S P; McMurry, L M; Hooper, D C; Wolfson, J S; Levy, S B

    1989-01-01

    Chromosomal multiple-antibiotic-resistant (Mar) mutants of Escherichia coli, selected on agar containing low concentrations of tetracycline or chloramphenicol, were 6- to 18-fold less susceptible to the fluoroquinolones than were their wild-type E. coli K-12 or E. coli C parental strains. The frequency of emergence of such mutants was at least 1,000-fold higher than that of those selected by the fluoroquinolone norfloxacin directly. When Mar mutants, but not wild-type cells, were plated on norfloxacin, mutants resistant to high levels of norfloxacin (2 micrograms/ml) appeared at a relatively high (approximately 10(-7] frequency. In addition to decreased amounts of OmpF, Mar mutants had other outer membrane protein changes and were four- to eightfold less susceptible to fluoroquinolones than was an ompF::Tn5 mutant lacking only OmpF. Accumulation of [3H]norfloxacin was more than threefold lower in the Mar mutants than in wild-type cells and twofold lower than in the OmpF-deficient derivative. These differences were not attributable to a change in the endogenous active efflux system for norfloxacin in E. coli. Norfloxacin-induced inhibition of DNA synthesis was threefold lower in intact cells of a Mar mutant than in susceptible cells, but this difference was not seen in toluene-permeabilized cells. Insertion of Tn5 into marA (min 34.05 on the chromosome) led to a return of the wild-type patterns of norfloxacin accumulation, fluoroquinolone and other antimicrobial agent susceptibilities, and outer membrane protein profile, including partial restoration of OmpF. These findings together suggest that marA-dependent fluoroquinolone resistance is linked to decreased cell permeability, only part of which can be accounted for by the reduction in OmpF. Once mutated to marA, cells can achieve high levels of quinolone resistance at a relatively high frequency. Images PMID:2679373

  4. BIOSYNTHESIS OF THE PHENYLPROPANOID MOIETY OF CHLORAMPHENICOL,

    DTIC Science & Technology

    measured. D-Glucose, labelled in carbons 1 or 2 or uniformly, was an efficient precursor of the p-nitrophenylserinol moiety and of the phenylpropanoid ...amino acids of the mycelium. Since phenylalanine and tyrosine were incorporated into the mycelium the biosynthetic route to the phenylpropanoid portion

  5. 21 CFR 524.390 - Chloramphenicol ophthalmic ointment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS... in dogs and cats—(1) Amount. Apply every 3 hours around the clock for 48 hours, after which night...

  6. 21 CFR 524.390 - Chloramphenicol ophthalmic ointment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS... in dogs and cats—(1) Amount. Apply every 3 hours around the clock for 48 hours, after which night...

  7. 21 CFR 520.390b - Chloramphenicol capsules.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... every 6 hours. (2) Indications for use. For treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections associated with...

  8. 21 CFR 520.390b - Chloramphenicol capsules.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... dogs—(1) Amount. 25 mg per pound of body weight every 6 hours. (2) Indications for use. For treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections associated with canine distemper caused by susceptible organisms....

  9. Cellular uptake and covalent binding of nitroso-chloramphenicol

    SciTech Connect

    Murray, T.; Yunis, A.A.

    1981-09-01

    A comparative study of the cellular transport of CAP and its nitroso derivative (NO-CAP) was carried out in Raji cells, a transformed human lymphoblastoid cell line. Both agents were concentrated by the cells by a factor of 3 (cellular/extracellular concentration ratio). The cellular uptake of NO-CAP, like that of CAP, was found to be rapid and temperature-independent. Thus the greater cytotoxicity of NO-CAP is apparently not due to an enhanced uptake of the nitroso derivative relative to CAP. In contrast to the similarity of uptake, NO-CAP becomes covalently bound to both Raji cells and freshly isolated human bone marrow cells to a much higher extent (15-fold). Also, cells previously loaded with CAP or NO-CAP retain three times as much of the nitroso compound during a 24 hr dialysis against a drug-free isotonic solution. The increased binding of NO-CAP to human hematopoietic cells attests to the greater reactivity of the p-substituted aromatic nitroso group and is consistent with the postulate that reduction products of the nitro group of CAP may be responsible for CAP-induced aplastic anemia.

  10. 21 CFR 520.390b - Chloramphenicol capsules.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... every 6 hours. (2) Indications for use. For treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections associated with...

  11. 21 CFR 520.390b - Chloramphenicol capsules.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... every 6 hours. (2) Indications for use. For treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections associated with...

  12. 21 CFR 520.390a - Chloramphenicol tablets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... weight by mouth every 6 hours. (2) Indications for use—(i) For the treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections... gastroenteritis associated with bacterial diarrhea, bacterial pulmonary infections, and bacterial......

  13. 21 CFR 520.390b - Chloramphenicol capsules.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... every 6 hours. (2) Indications for use. For treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections associated with...

  14. 21 CFR 520.390a - Chloramphenicol tablets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... weight by mouth every 6 hours. (2) Indications for use—(i) For the treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections... gastroenteritis associated with bacterial diarrhea, bacterial pulmonary infections, and bacterial......

  15. 21 CFR 520.390a - Chloramphenicol tablets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... weight by mouth every 6 hours. (2) Indications for use—(i) For the treatment of bacterial pulmonary infections, bacterial infections of the urinary tract, bacterial enteritis, and bacterial infections... gastroenteritis associated with bacterial diarrhea, bacterial pulmonary infections, and bacterial......

  16. 21 CFR 524.390b - Chloramphenicol ophthalmic solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS...) Limitations. Therapy for cats should not exceed 7 days. As with other antibiotics, prolonged use may result in... animals. The length of time that residues persist in milk or tissues has not been determined. Federal...

  17. 77 FR 4895 - New Animal Drugs; Chloramphenicol, Diethylcarbamazine Citrate, Hygromycin B, Methoxyflurane...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ...: (i) No. 061623 for 50-, 100-, 250-, and 500-mg; and 1-g tablets; (ii) (c) Conditions of use in dogs... Nos. 000856 and 025463 in Sec. 510.600(c) of this chapter. (c) Conditions of use in dogs and cats--(1...

  18. Serum Zinc, Iron, and Copper Concentrations during Typhoid Fever in Man: Effect of Chloramphenicol Therapy

    DTIC Science & Technology

    1974-11-12

    Received Nov. 12I~aepe Dec. 16,1974. Study 1. Nineteen healthy men, inmates of the MS CLINICAL CHEMISTRY , Vol. 21.14o. 4, 1975 - Best Available Copy Maryland...thenap and mserum rm concentrfations. nificant depressions of serum iron and zinc conoen- aM CLINICAL CHEMISTRY , Vol. 21.4o. 4. 10754 *IE EWZX 1~001...evidenc, was in the absence between 30-40% of the zinc bound in serum (16), we CLINICAL CHEMISTRY . Vol. 21. No. 4,1975 531 saw no significant changes in

  19. Characterisation of a mobilisable plasmid conferring florfenicol and chloramphenicol resistance in Actinobacillus pleuropneumoniae.

    PubMed

    Bossé, Janine T; Li, Yanwen; Atherton, Tom G; Walker, Stephanie; Williamson, Susanna M; Rogers, Jon; Chaudhuri, Roy R; Weinert, Lucy A; Holden, Matthew T G; Maskell, Duncan J; Tucker, Alexander W; Wren, Brendan W; Rycroft, Andrew N; Langford, Paul R

    2015-08-05

    The complete nucleotide sequence of a 7.7kb mobilisable plasmid (pM3446F), isolated from a florfenicol resistant isolate of Actinobacillus pleuropneumoniae, showed extended similarity to plasmids found in other members of the Pasteurellaceae containing the floR gene as well as replication and mobilisation genes. Mobilisation into other Pasteurellaceae species confirmed that this plasmid can be transferred horizontally.

  20. 77 FR 41412 - Determination That CHLOROMYCETIN (Chloramphenicol) Capsules, 250 Milligrams, Were Withdrawn From...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-13

    ... number of adverse reactions, the most serious being bone marrow depression (anemia, thrombocytopenia, and granulocytopenia temporally associated with treatment). A boxed warning in the prescribing information for...

  1. Beneficial effect of Berberis buxifolia Lam, Ziziphus mistol Griseb and Prosopis alba extracts on oxidative stress induced by chloramphenicol.

    PubMed

    Albrecht, Claudia; Pellarin, Gabriela; Rojas, María José; Albesa, Inés; Eraso, Alberto F

    2010-01-01

    The chemiluminescence of luminol, a measure of oxidative stress, increased immediately as a consequence of reactive oxygen species (ROS) stimulated by this antibiotic. The effect of Ch was dose dependent with maximum stimulus at 8 mg/ml (Vmax); above this concentration the cells began to reduce the production of ROS. The oxidative injury of Ch was counteracted by water extracts of Berberis buxifolia lam, Zizyphus mistol Griseb and Prosopis alba, indigenous fruits from Argentina. The relatively light units (RLU) emitted decreased immediately as a consequence of a protective effect exerted by the extracts of these fruit extracts on blood cells. The three indigenous fruit extracts reduced to a different extent the oxidative injury caused by Ch. B.buxifolia lam exhibited the highest antioxidant capacity followed by Z.mistol Griseb. Water extracts of both fruit extracts were the most effective against the oxidative stress, while P.alba presented better antioxidant capacity in the ethanolic fraction obtained. Hexane extracts showed low protective action on blood cells, with little reduction of area under curve (AUC) of RLU plotted versus time. Leukocytes remained viable in blood samples incubated for 3h with Ch and water extracts of B. buxifolia lam or Z. mistol Griseb (97.1% and 92.5% viability by Trypan blue exclusion, respectively); whereas with Ch only the cells were stressed and viability decreased to 30%. The three fruit extracts protected the viability of leukocytes in parallel with the decrease of ROS. Erythrocytes were not lysed in the presence of Ch.

  2. Antibacterial application of engineered bacteriophage nanomedicines: antibody-targeted, chloramphenicol prodrug loaded bacteriophages for inhibiting the growth of Staphylococcus aureus bacteria.

    PubMed

    Vaks, Lilach; Benhar, Itai

    2011-01-01

    The increasing development of bacterial resistance to traditional antibiotics has reached alarming levels, thus there is an urgent need to develop new antimicrobial agents. To be effective, these new antimicrobials should possess novel modes of action and/or different cellular targets compared with existing antibiotics. Bacteriophages (phages) have been used for over a century as tools for the treatment of bacterial infections, for nearly half a century as tools in genetic research, for about two decades as tools for the discovery of specific target-binding proteins and peptides, and for almost a decade as tools for vaccine development. We describe a new application in the area of antibacterial nanomedicines where filamentous phages can be formulated as targeted drug-delivery vehicles of nanometric dimensions (phage nanomedicines) and used for therapeutic purposes. This protocol involves both genetic and chemical engineering of these phages. The genetic engineering of the phage coat, which results in the display of a target-specificity-conferring peptide or protein on the phage coat, can be used to design the drug-release mechanism and is not described herein. However, the methods used to chemically conjugate cytotoxic drugs at high density on the phage coat are described. Further, assays to measure the drug load on the surface of the phage and the potency of the system in the inhibition of growth of target cells as well as assessment of the therapeutic potential of the phages in a mouse disease model are discussed.

  3. Chloramphenicol and tetracycline decrease motility and increase invasion and attachment gene expression in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    USDA-ARS?s Scientific Manuscript database

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most common serovars isolated from humans and livestock, and over 35 percent of these isolates are resistant to three or more antibiotics. Multidrug-resistant (MDR) Salmonella is a public health concern as it is associated with i...

  4. In vitro antimicrobial production of beta-lactamases, aminoglycoside-modifying enzymes, and chloramphenicol acetyltransferase by and susceptibility of clinical isolates of Acinetobacter baumannii.

    PubMed Central

    Vila, J; Marcos, A; Marco, F; Abdalla, S; Vergara, Y; Reig, R; Gomez-Lus, R; Jimenez de Anta, T

    1993-01-01

    Antimicrobial susceptibility testing was performed on 54 epidemiologically unrelated clinical isolates of Acinetobacter baumannii by using a standard agar dilution technique. On the basis of the in vitro activities, imipenem and doxycycline were the most active agents, whereas amikacin, isepamicin, and the new fluorquinolones ciprofloxacin and ofloxacin presented moderate activity. Cephalosporinase activity was found in 98% of the strains, whereas lactamases of TEM type 1 and one with a pI of 7 to 7.5 were present in 16 and 11% of the strains, respectively. Resistance to aminoglycosides was explained by the production of the three classes of aminoglycoside-modifying enzymes, with predominance of aminoglycoside-3'-phosphotransferase VI in 28% of the strains. PMID:8431011

  5. Comparison of rose bengal-chloramphenicol and modified aureomycin-rose bengal-glucose-peptone agar as media for the enumeration of molds and yeasts in water by membrane filtration techniques.

    PubMed

    Albaum, Silva; Masaphy, Segula

    2009-03-01

    The present study compares the suitability of rose bengalchloramphenicol (RBCh) and modified aureomycin-rose bengal glucose-peptone agar for enumerating fungi recovered from diverse water sources using the membrane filtration method. Both mold and yeast colonies were established more rapidly, with more intensified colony colors and higher RBCh counts.

  6. Antibiotic therapy for bacterial meningitis in children in developing countries.

    PubMed Central

    Kumar, P.; Verma, I. C.

    1993-01-01

    We carried out a study to investigate the effectiveness of chloramphenicol alone as a treatment for bacterial meningitis. A total of 70 consecutive children aged > 3 months with bacterial meningitis, who had been admitted to the paediatric hospital of the All India Institute of Medical Sciences, were randomized to receive chloramphenicol alone or chloramphenicol + penicillin. The two groups were matched with each other. Treatment failure occurred with three (9%) patients in the chloramphenicol-alone group and with four (12.1%) patients in the combination therapy group (P > 0.05). The mean duration of intravenous therapy, the number of intravenous cannulae used per patient, and the incidence of thrombophlebitis were significantly higher for the group that received the combination therapy. Also, the cost of using chloramphenicol + penicillin was four times higher than that of chloramphenicol alone. Hence, chloramphenicol alone was as effective as chloramphenicol + penicillin and much cheaper and more convenient to use. PMID:8490981

  7. Antibiotic resistance pattern among gram-negative bacteria isolated from raw milk in Multan.

    PubMed

    Farzana, Kalsoom; Jabeen, Farzana; Shah, Syed Nisar Hussain

    2005-07-01

    The use of raw milk in Pakistan has led to the antibiotics resistance. This investigation has showed incidence and antibiotic resistance among Coliform and Klebsiella to nalidixic acid, urixin and little to chloramphenicol. Enterobacter was sensitive to nalidixic acid, tetracycline and showed little resistance to chloramphenicol. E. coli were very sensitive to nalidixic acid, tetracycline, chloramphenicol, urixin, amoxil and with no resistance to ceftriaxone.

  8. UGA can be decoded as tryptophan at low efficiency in Bacillus subtilis.

    PubMed Central

    Lovett, P S; Ambulos, N P; Mulbry, W; Noguchi, N; Rogers, E J

    1991-01-01

    Replacement of cat-86 codon 7 or 144 with the UGA codon permitted the gene to confer chloramphenicol resistance in wild-type Bacillus subtilis. UAA replacements of the same codons resulted in a chloramphenicol-sensitive phenotype in wild-type B. subtilis and a chloramphenicol-resistant phenotype in suppressor-positive strains. N-terminal sequencing showed that UGA at codon 7 was decoded as tryptophan in wild-type cells, at an efficiency of about 6%. Images PMID:1900283

  9. RESTORATION OF NORMAL GLUTAMIC ACID TRANSPORT IN VITAMIN B6-DEFICIENT LACTOBACILLUS PLANTARUM BY ACETATE, AMMONIUM, AND VITAMIN B6,

    DTIC Science & Technology

    GLUTAMIC ACID, * LACTOBACILLUS , VITAMIN B COMPLEX, METABOLIC DISEASES, VITAMIN B COMPLEX, ACETATES, AMMONIUM COMPOUNDS, CHLORAMPHENICOL, DEOXYRIBONUCLEIC ACIDS, AMINO ACIDS, PENICILLINS, CELL WALL, SYNTHESIS, OSMOSIS.

  10. Aeromedical Aspects of CH-47C Helicopter Self-Deployment (Operation Northern Leap),

    DTIC Science & Technology

    1980-03-01

    mgm/cc) 20 cc Calcium chloride 10% ( prefilled syringes ) # 2 Chloramphenicol ophthalmic ointment # 3 Chloramphenicol ophthalmic solution 45 cc...Storage box, tool chest type with double lock # 1 Swabs, alcohol and betadine 100 of each Syringes and needles (assorted sizes) # 10 32 APPENDIX B

  11. [Experience with vaginal suppositories containing chemotherapeutic agents (author's transl)].

    PubMed

    Török, J; Kószó, E; Altmayer, P; Mezey, G

    1981-01-01

    The authors determined the release of chloramphenicol, oxytetracycline, neomycin and sulphadimidine from different bases (polyoxethene mass, solid fat, 95% solid fat +5% Span 20). The diffusion of chloramphenicol and sulphadimidine was best from hydrophilic bases; that of oxytetracycline and neomycin, from emulsifier-containing lipophil bases. This may be explained by the solubilities of the pharmaca and by interactions between base and active substance.

  12. Synergistic Interactions of Methanolic Extract of Acacia mearnsii De Wild. with Antibiotics against Bacteria of Clinical Relevance

    PubMed Central

    Olajuyigbe, Olufunmiso O.; Afolayan, Anthony J.

    2012-01-01

    With the emergence of multidrug-resistant organisms, combining medicinal plants with synthetic or orthodox medicines against resistant bacteria becomes necessary. In this study, interactions between methanolic extract of Acacia mearnsii and eight antibiotics were investigated by agar diffusion and checkerboard assays. The minimum inhibitory concentrations (MICs) of all the antibiotics ranged between 0.020 and 500 μg/mL while that of the crude extract varied between 0.156 and 1.25 mg/mL. The agar diffusion assay showed that extract-kanamycin combination had zones of inhibition ≥20 ± 1.0 mm in all the bacteria tested (100%), followed by extract-chloramphenicol (90%) > extract-ciprofloxacin = extract-tetracycline (70%) > extract-amoxicillin (60%) > extract-nalidixic acid (50%) > extract-erythromycin (40%) > extract-metronidazole (20%). The checkerboard showed synergistic interaction (61.25%), additivity/indifference (23.75%) and antagonistic (15%) effects. The synergistic interaction was most expressed by combining the extract with tetracycline, metronidazole, amoxicillin, ciprofloxacin, chloramphenicol and nalidixic acid against E. coli (ATCC 25922), erythromycin, metronidazole, amoxicillin, chloramphenicol and kanamycin against S. aureus (ATCC 6538), erythromycin, tetracycline, amoxicillin, nalidixic acid and chloramphenicol against B. subtilis KZN, erythromycin, metronidazole and amoxicillin against E. faecalis KZN, erythromycin, tetracycline, nalidixic acid and chloramphenicol against K. pneumoniae (ATCC 10031), erythromycin, tetracycline, metronidazole and chloramphenicol against P. vulgaris (ATCC 6830), erythromycin, tetracycline, amoxicillin and chloramphenicol against S. sonnei (ATCC 29930), metronidazole, amoxicillin and chloramphenicol against E. faecalis (ATCC 29212) and ciprofloxacin and chloramphenicol against Proteus vulgaris KZN. The synergistic interactions indicated that the bactericidal potentials of the antibacterial agents were improved and

  13. Isolation and characterization of the grain mold fungi, Cochliobolus and Alternaria spp., from sorghum using semi-selective media and DNA sequence analyses

    USDA-ARS?s Scientific Manuscript database

    Mold diseases, caused by fungal complexes including Alternaria, Cochliobolus and Fusarium species, limit sorghum grain production. Media were tested by plating Fusarium thapsinum, Alternaria sp. and Curvularia lunata, individually and competitively. Dichloran chloramphenicol rose bengal (DRBC) and m...

  14. Evidence for the presence of an endosymbiont in the Pecan Scab pathogen Venturia effusa (basyonym: Fusicladium effusum)

    USDA-ARS?s Scientific Manuscript database

    Aims: To determine whether Venturia effusa (basyonym: Fusicladium effusum) the causative fungal agent of Pecan Scab harbors a bacterial symbiont. Methods and Results: Beginning with monoconidial isolates, V. effusa was maintained on potato dextrose agar amended with antibiotics (chloramphenicol 10...

  15. Mechanisms of antimicrobial resistance and genetic relatedness among enterococci isolated from dogs and cats in the United States

    USDA-ARS?s Scientific Manuscript database

    Aims: In this study, mechanisms of antimicrobial resistance and genetic relatedness among resistant enterococci from dogs and cats in the United States were determined. Methods and Results: Enterococci resistant to chloramphenicol, ciprofloxacin, erythromycin, gentamicin, kanamycin, streptomycin,...

  16. FUNDAMENTALS OF THE STUDY OF ANTIBIOTICS,

    DTIC Science & Technology

    ANTIBIOTICS, BIOSYNTHESIS), PHARMACOLOGY, MICROORGANISMS, CLASSIFICATION, PRODUCTION, CULTURE MEDIA, POLYMYXINS, STREPTOMYCINS, TETRACYCLINES ...CHLORAMPHENICOL, OXYTETRACYCLINE , CHLORTETRACYCLINE, PENICILLINS, FUNGI, PLANTS(BOTANY), RESISTANCE(BIOLOGY), PREPARATION, PURIFICATION, AGRICULTURE, CANNING, ECOLOGY, FOOD, MILK, PRESERVATION, USSR

  17. Electrooptical Analysis of Microbial Cell Suspensions forDetermination of Antibiotic Resistance.

    PubMed

    Guliy, Olga I; Bunin, Victor D; Korzhenevich, Vyacheslav I; Volkov, Alexey A; Ignatov, Oleg V

    2016-12-01

    The effects of ampicillin; kanamycin, chloramphenicol, and tetracycline on electrophysical characteristics of cells of sensitive (ampicillin; kanamycin, chloramphenicol) and resistant (ampicillin; kanamycin, chloramphenicol, tetracycline) Escherichia coli strains were studied. Under the action of antibiotics sensitive and resistant E. coli strains acquire different electro-optical properties. Changes in suspension-orientational spectra, that are observed under the action of ampicillin; kanamycin, chloramphenicol, and tetracycline can be used in determination of antibiotic resistance of the studied bacterial strains. In our opinion, the methods of microbial suspension electro-optical analysis can be used in microbiology, mеdicinе, veterinary, and are an effective tool for solving the problems connected with determination of microbial cell antibiotic resistance.

  18. Genetics of NAD metabolism in Salmonella typhimurium and cloning of the nadA and pnuC loci.

    PubMed

    Tirgari, S; Spector, M P; Foster, J W

    1986-09-01

    The nadA and pnuC loci of S. typhimurium were cloned and found to reside within a 2.2-kilobase region. Two-dimensional O'Farrell gel electrophoresis of the proteins produced after chloramphenicol amplification and subsequent release from chloramphenicol inhibition revealed NadA and PnuC to be 43,000- and 25,000-molecular-weight proteins, respectively. The data indicated that nadA and pnuC represent two distinct genes.

  19. Susceptibilities of species of the Bacteroides fragilis group to 10 antimicrobial agents.

    PubMed Central

    Betriu, C; Campos, E; Cabronero, C; Rodriguez-Avial, C; Picazo, J J

    1990-01-01

    A total of 94 clinical isolates of the Bacteroides fragilis group was tested for susceptibility to metronidazole, chloramphenicol, clindamycin, cefoxitin, cefotetan, cefmetazole, moxalactam, mezlocillin, amoxicillin-clavulanic acid, and imipenem. All the strains tested were susceptible to imipenem, metronidazole, amoxicillin-clavulanic acid, and chloramphenicol. The rate of resistance to clindamycin was 21%. The results of this study demonstrate a difference in resistance rates from one species of the B. fragilis group to another. PMID:2344174

  20. Effect of a Salmonella Group H1 R Factor on Virulence and Response of Infections to Antimicrobial Therapy

    PubMed Central

    Butler, Thomas; Shuster, C. W.; Franco, Amalia

    1979-01-01

    A group H1 R factor encoding resistance to chloramphenicol, streptomycin, sulfonamide, and tetracycline was transferred into Salmonella typhimurium LT-2. The virulence of LT-2 for mice, as assessed by intraperitoneal 50% lethal dose and the number of organisms in the spleen, was not affected by the R factor. On the other hand, the R factor conferred resistance in mouse infections to therapy with chloramphenicol and trimethoprim plus sulfamethoxazole. PMID:380460

  1. Chloroamphenicol-Induced Hemolysis in Caucasian Glucose-6-Phosphate Dehydrogenase Deficiency

    DTIC Science & Technology

    typhoid fever with chloramphenicol. Two of these patients were studied when free of infection to determine the hemolytic potential of chloramphenicol in the noninfected G6PD-deficient white person. It was found to be mildly hemolytic under these conditions, suggesting that a drug- disease synergism was primarily responsible for the clinical hemolytic reactions. The febrile state itself, or changes in plasma amino acids accompanying infection, may be responsible for disease-related

  2. [Change of Electrophysical Properties of Escherichia coli Cells Due to Levomycetin and Tetracycline Action].

    PubMed

    Guliy, O I; Bunin, V D; Larionova, O S; Zhnichkova, E G; Balkos, A B; Ignatov, O V

    2016-01-01

    The effect of chloramphenicol and tetracycline, as inhibitors of protein synthesis, on electrophysical properties of Escherichia coli K-12 cells was investigated. Significant changes in the orientation spectra (OS) of the cell suspensions incubated with various concentrations of chloramphenicol were observed only at the first five frequencies of the electric field (10-1000 kHz). When the cells were exposed to chloramphenicol (1.5 mcg/ml) or tetracycline (1.7 mcg/ml), no changes in the OS were recorded. Significant changes in the electrooptic signal were observed, when the K-12 cells were simultaneously incubated with chloramphenicol (1.5 mcg/ml) and tetracycline (1.7 mcg/ml), that could be due to the synergistic action of the antibiotics. Therefore, the electrooptic analysis provided registration of higher antibacterial effect with the simultaneous use of chloramphenicol and tetracycline. Additional control experiments with the cell culture on the LB nutrient medium containing chloramphenicol and tetracycline were performed. The results suggested that the use of electrophysical methods for investigation of antibiotics effect on microorganisms was rather efficient.

  3. Identification of plant-induced genes of the bacterial pathogen Xanthomonas campestris pathovar campestris using a promoter-probe plasmid.

    PubMed

    Osbourn, A E; Barber, C E; Daniels, M J

    1987-01-01

    A promoter-probe plasmid suitable for use in Xanthomonas campestris pathovar campestris (causal agent of crucifer black rot) was constructed by ligating a broad host range IncQ replicon into the promoter-probe plasmid pKK232-8, which contains a promoterless chloramphenicol acetyltransferase gene. Xanthomonas chromosomal DNA fragments were 'shotgun' cloned into a restriction site in front of this gene, and the resulting library was transferred en masse into Xanthomonas. Individual transconjugants possessing DNA insertions with promoter activity in plants were identified by virtue of their ability to infect chloramphenicol-treated turnip seedlings. Of 19 transconjugants identified in this way five were chloramphenicol resistant both in turnip seedlings and on agar plates. However the remaining 14 were only chloramphenicol resistant in planta, and thus apparently contained plant-inducible promoter fragments. Resistance to chloramphenicol was correlated with increased chloramphenicol acetyltransferase activity for the transconjugants assayed. The promoter fragments were used to isolate genomic clones from a library, and the role of the genes contained in these clones in pathogenicity is being investigated.

  4. The Glycolate Pathway and Photosynthetic Competence in Euglena

    PubMed Central

    Davis, Barry; Merrett, Michael J.

    1975-01-01

    The development of glycolate pathway enzymes has been determined in relation to photosynthetic competence during the regreening of Euglena cultures. Phosphoglycolate phosphatase and glycolate dehydrogenase rapidly reached maximal levels of activity but the complete development of ribulose 1,5-diphosphate carboxylase and concomitant photosynthetic carbon dioxide fixation were not attained until 72 hours of illumination. Specific inhibitors of protein synthesis showed that the formation of ribulose 1,5-diphosphate carboxylase in both division-synchronized and regreening cultures was prevented by both cycloheximide and d-threo-chloramphenicol, whereas phosphoglycolate phosphatase formation was only inhibited by d-threo-chloramphenicol but not by l-threo-chloramphenicol or cycloheximide. Since cycloheximide prevented ribulose diphosphate carboxylase synthesis and photosynthetic carbon dioxide fixation without affecting phosphoglycolate phosphatase synthesis during regreening, it was concluded that photosynthetic competence was not necessary for the development of the glycolate pathway enzymes. The inhibition of phosphoglycolate phosphatase synthesis by d-threo-chloramphenicol but not by l-threo-chloramphenicol or cycloheximide shows that the enzyme was synthesized exclusively on chloroplast ribosomes, whereas protein synthesis on both chloroplast and cytoplasmic ribosomes was required for the formation of ribulose 1,5-diphosphate carboxylase. Although light is required for the development of both Calvin cycle and glycolate pathway enzymes during regreening it is concluded that the two pathways are not coordinately regulated. PMID:16659023

  5. [Macrolides in the treatment of children with Mediterranean spotted fever].

    PubMed

    Cascio, Antonio; Colomba, Claudia

    2002-09-01

    Till now there is not a gold standard therapy for Mediterranean spotted fever (MSF) in children. Standard treatment for MSF is the administration of tetracycline or chloramphenicol, however both these drugs can cause significant adverse effects in children (tetracyclines can cause staining of teeth, chloramphenicol severe hematological adverse events such as aplastic anemia, gray baby syndrome and hemolytic anemia in patients with the Mediterranean form of G6PD deficiency). We conducted two randomized clinical trials; the first compared clarithromycin versus chloramphenicol: mean time to defervescence was 36.7 +/- 18.1 h in the clarithromycin group and 47.1+/- 21.9 h in the chloramphenicol group (P= 0.047). The second trial compared clarithromycin versus azithromycin and did not show any statistically significant difference: mean time to defervescence was 46.2 +/- 36.4 h in the clarithromycin group and 39.3 +/- 31.3 h in the azithromycin group (P= 0.34). On the basis of these studies we think that clarithromycin and azithromycin could constitute an acceptable alternative to chloramphenicol and to tetracyclines for the treatment of MSF in children

  6. Effect of organic toxicants on the activity of denitrifying granular sludge.

    PubMed

    Zhang, Zonghe; Zheng, Ping; Li, Wei; Wang, Ru; Ghulam, Abbas

    2015-01-01

    Denitrification plays a key role in the biological nitrogen removal from the wastewater using granular sludge as the integral part of a high-rate denitrification technology. It is helpful to evaluate the effect of typical organic toxicants on the activity of denitrifying granular sludge for the application of denitrification technology. In this study, four typical organic toxicants, namely, penicillin, chloramphenicol, 2,4-dinitrophenol and polymyxin B sulphate were used to assess the effect of organic toxicants on the activity of denitrifying granular sludge. The results of individual toxicity indicated that penicillin, chloramphenicol and 2,4-dinitrophenol had significant inhibition, whose half-inhibitory concentrations were 0.534, 0.162 and 0.474 g/L with respective inhibitory magnitudes of 90.79%/(g/L), 282.5%/(g/L) and 138.83%/(g/L). Polymyxin B sulphate showed no significant inhibition. The results of combined toxicity indicated that the binary mixture of penicillin and chloramphenicol had an antagonistic effect, both the binary mixture of penicillin and 2,4-dinitrophenol and the binary mixture of chloramphenicol and 2,4-dinitrophenol had additive effects. The ternary mixture of penicillin, chloramphenicol and 2,4-dinitrophenol had a partial additive effect.

  7. Synergistic activity of coriander oil and conventional antibiotics against Acinetobacter baumannii.

    PubMed

    Duarte, A; Ferreira, S; Silva, F; Domingues, F C

    2012-02-15

    In this study we investigated the existence of synergistic antibacterial effect between coriander (Coriandrum sativum L.) essential oil and six different antibacterial drugs (cefoperazone, chloramphenicol, ciprofloxacin, gentamicin, tetracycline and piperacillin). The antibacterial activity of coriander oil was assessed using microdilution susceptibility testing and synergistic interaction by checkerboard assays. The association of coriander essential oil with chloramphenicol, ciprofloxacin, gentamicin and tetracycline against Acinetobacter baumannii showed in vitro effectiveness, which is an indicator of a possible synergistic interaction against two reference strains of A. baumannii (LMG 1025 and LMG 1041) (FIC index from 0.047 to 0.375). However, when tested the involvement between coriander essential oil and piperacillin or cefoperazone, the isobolograms and FIC index showed an additive interaction. The in vitro interaction could improve the antimicrobial effectiveness of ciprofloxacin, gentamicin and tetracycline and may contribute to resensitize A. baumannii to the action of chloramphenicol. Copyright © 2011 Elsevier GmbH. All rights reserved.

  8. Streamlined Synthesis and Assembly of a Hybrid Sensing Architecture with Solid Binding Proteins and Click Chemistry.

    PubMed

    Swift, Brian J F; Shadish, Jared A; DeForest, Cole A; Baneyx, François

    2017-03-13

    Combining bioorthogonal chemistry with the use of proteins engineered with adhesive and morphogenetic solid-binding peptides is a promising route for synthesizing hybrid materials with the economy and efficiency of living systems. Using optical sensing of chloramphenicol as a proof of concept, we show here that a GFP variant engineered with zinc sulfide and silica-binding peptides on opposite sides of its β-barrel supports the fabrication of protein-capped ZnS:Mn nanocrystals that exhibit the combined emission signatures of organic and inorganic fluorophores. Conjugation of a chloramphenicol-specific DNA aptamer to the protein shell through strain-promoted azide-alkyne cycloaddition and spontaneous concentration of the resulting nanostructures onto SiO2 particles mediated by the silica-binding sequence enables visual detection of environmentally and clinically relevant concentrations of chloramphenicol through analyte-mediated inner filtering of sub-330 nm excitation light.

  9. Plasmid coding for transferable drug resistance in bacteria isolated from cultured rainbow trout.

    PubMed Central

    Toranzo, A E; Combarro, P; Lemos, M L; Barja, J L

    1984-01-01

    The occurrence of drug resistance and plasmid-mediated transferability was investigated in 170 strains belonging to eight bacterial groups isolated from cultured rainbow trout. It was found that 87.6% of the strains were resistant to at least one drug, with the highest percentages of resistance being detected for ampicillin (54.7%), sulfadiazine (46.5%), nitrofurantoin (38.2%), and chloramphenicol (37.0%). Six enterobacteria, two Vibrio, and one Aeromonas isolate transferred resistance factors to Escherichia coli K-12. The most common transmissible R factor determined resistance to chloramphenicol and sulfadiazine, demonstrating an association between a specific plasmid and the resistance pattern transferred. The presence of chloramphenicol in fish food was detected by bioassay. In general, transfer frequencies were similar in primary and secondary matings, which indicate the potential water-borne dissemination of these R plasmids. Images PMID:6508296

  10. Clinical and Pathological Evaluation of Sulbactam/Ampicillin for Treatment of Experimental Bovine Pneumonic Pasteurellosis

    PubMed Central

    Gifford, Glen A.; Potter, Andrew A.; Babiuk, Lorne A.

    1988-01-01

    An experiment was conducted to evaluate the efficacy of sulbactam/ampicillin for treatment of bovine pneumonic pasteurellosis. Twenty-one Hereford calves were experimentally infected with bovine herpesvirus-1 and an ampicillin-resistant strain of Pasteurella haemolytica, then treated for three days with either sulbactam/ampicillin, chloramphenicol, or a placebo. The treatments were evaluated by comparing clinical illness scores, total sick days, weight changes, mortality rates, and postmortem lung scores between treatment groups. Both antibiotics were highly effective in reducing respiratory disease in the experimentally infected calves. The clinical response to sulbactam/ampicillin treatment was comparable with that of chloramphenicol and was significantly improved compared with the response to the placebo treatment. These findings suggest that the efficacy of sulbactam/ampicillin may be comparable to that of chloramphenicol for treatment of pneumonic pasteurellosis involving ampicillin-resistant strains of P. haemolytica. PMID:17422967

  11. mRNA translation during oocyte maturation plays a key role in development of primordial germ cells in Xenopus embryos.

    PubMed

    Zeynali, Bahman; Dixon, Keith E

    2004-09-01

    It is believed that cytoplasmic localization in the egg is necessary for development of primordial germ cells (PGCs) in Xenopus embryos. In this study, we sought to determine if translation of maternal mRNA during oocyte maturation is involved in the development of PGCs. Donor oocytes were collected from both stimulated (those who receive gonadotropin) and unstimulated females, artificially matured and fertilized using a host transfer technique. Using chloramphenicol (50 microM and 500 microM RNA), RNA translation was inhibited during oocyte maturation. Our results showed that in unstimulated embryos treated with 50 microM chloramphenicol, there was a significant reduction in the number of PGCs reaching genital ridges. In stimulated embryos, however, the number of PGCs was unchanged unless a higher concentration (500 microM) of chloramphenicol was used. From these results it is suggested that maternal mRNA translation during oocyte maturation plays a key role in development of PGCs.

  12. Antibiotic Resistance Trends in Enteropathogenic Bacteria Isolated in 1985–1987 and 1995–1998 in Barcelona

    PubMed Central

    Prats, Guillermo; Mirelis, Beatriz; Llovet, Teresa; Muñoz, Carmen; Miró, Elisenda; Navarro, Ferran

    2000-01-01

    Trends in resistance to antimicrobial agents used for therapy have been evaluated with 3,797 enteropathogenic bacteria, Campylobacter, Salmonella, Shigella, and Yersinia, between 1985–1987 and 1995–1998. The greater increase in the rate of resistance was observed in Campylobacter jejuni for quinolones (from 1 to 82%) and tetracycline (from 23 to 72%) and in gastroenteric salmonellae for ampicillin (from 8 to 44%), chloramphenicol (from 1.7 to 26%), and trimethoprim-sulfamethoxazole and nalidixic acid (from less than 0.5 to 11%). Multidrug resistance was detected in several Salmonella serotypes. In the 1995–1998 period, 76% of Shigella strains were resistant to trimethoprim-sulfamethoxazole, 43% were resistant to ampicillin, and 39% were resistant to chloramphenicol. Seventy-two percent of Yersinia enterocolitica O3 strains were resistant to streptomycin, 45% were resistant to sulfonamides, 28% were resistant to trimethoprim-sulfamethoxazole, and 20% were resistant to chloramphenicol. PMID:10770742

  13. Genetics of NAD metabolism in Salmonella typhimurium and cloning of the nadA and pnuC loci.

    PubMed Central

    Tirgari, S; Spector, M P; Foster, J W

    1986-01-01

    The nadA and pnuC loci of S. typhimurium were cloned and found to reside within a 2.2-kilobase region. Two-dimensional O'Farrell gel electrophoresis of the proteins produced after chloramphenicol amplification and subsequent release from chloramphenicol inhibition revealed NadA and PnuC to be 43,000- and 25,000-molecular-weight proteins, respectively. The data indicated that nadA and pnuC represent two distinct genes. Images PMID:3017917

  14. Effect of Haemophilus influenzae infection and moxalactam on platelet function in children.

    PubMed Central

    Kaplan, S L; Courtney, J T; Kenal, K A

    1987-01-01

    In a prospective randomized study, children with Haemophilus influenzae type b meningitis received moxalactam or ampicillin or chloramphenicol. Of 41 children, 6 had prolonged bleeding times (greater than 6 min), and 7 of 9 tested had abnormal platelet aggregation at hospital admission. At the end of therapy, no children in the ampicillin-chloramphenicol group, compared with 5 of 22 moxalactam-treated children (23%) (P = 0.08), had prolonged bleeding times (6.5 to 7.5 min). Our data suggest that H. influenzae meningitis and treatment with moxalactam may each have an effect on platelet function in children. PMID:3579263

  15. Transduction of Gal+ by Coliphage T1 III. Requirement for Transcription and Translation in Recipient Cells

    PubMed Central

    Drexler, Henry

    1973-01-01

    A 10- to 15-min derepression of a λ prophage in a Gal− recipient during early infection with a transducing lysate of coliphage T1am will cause an increase in the efficiency of transduction of Gal+. An increase in the efficiency of transduction occurs when the donor is either nonlysogenic or lysogenic for λ; the increase is blocked by rifampin or chloramphenicol. With strain R901 it has been shown that efficient transduction can be blocked by treatment with rifampin after all chloramphenicol-sensitive steps have occurred. PMID:4587757

  16. Silencing of antibiotic resistance in E. coli with engineered phage bearing small regulatory RNAs.

    PubMed

    Libis, Vincent K; Bernheim, Aude G; Basier, Clovis; Jaramillo-Riveri, Sebastián; Deyell, Matthew; Aghoghogbe, Idonnya; Atanaskovic, Iva; Bencherif, Amel Camélia; Benony, Marguerite; Koutsoubelis, Nicolas; Löchner, Anne C; Marinkovic, Zoran S; Zahra, Sarah; Zegman, Yonatan; Lindner, Ariel B; Wintermute, Edwin H

    2014-12-19

    In response to emergent antibiotic resistance, new strategies are needed to enhance the effectiveness of existing antibiotics. Here, we describe a phagemid-delivered, RNA-mediated system capable of directly knocking down antibiotic resistance phenotypes. Small regulatory RNAs (sRNAs) were designed to specifically inhibit translation of chloramphenicol acetyltransferase and kanamycin phosphotransferase. Nonlytic phagemids coding for sRNA expression were able to infect and restore chloramphenicol and kanamycin sensitivity to populations of otherwise resistant E. coli. This modular system could easily be extended to other bacteria with resistance profiles that depend on specific transcripts.

  17. Tryptophanless Death in Bacillus subtilis

    PubMed Central

    Majerfeld, Irene; Barlati, Sergio; Ciferri, Orio

    1970-01-01

    A decline in colony-forming ability is observed in actively growing cultures of a tryptophan arginine auxotroph of Bacillus subtilis after removal of tryptophan (tryptophanless death). This phenomenon can be prevented by simultaneous starvation of the other required amino acid or by chloramphenicol administered in bacteriostatic concentration but not by actinomycin. Addition of tryptophan analogues not only prevents the death but also allows recovery of the cells that have lost the ability to form colonies on solid media. The term tryptophanless death is therefore inappropriate. Chloramphenicol but not actinomycin inhibits the recovery brought about by tryptophan analogues. PMID:4189906

  18. Direct Introduction of Genes into Rats and Expression of the Genes

    NASA Astrophysics Data System (ADS)

    Benvenisty, Nissim; Reshef, Lea

    1986-12-01

    A method of introducing actively expressed genes into intact mammals is described. DNA precipitated with calcium phosphate has been injected intraperitoneally into newborn rats. The injected genes have been taken up and expressed by the animal tissues. To examine the generality of the method we have injected newborn rats with the chloramphenicol acetyltransferase prokaryotic gene fused with various viral and cellular gene promoters and the gene for hepatitis B surface antigen, and we observed appearance of chloramphenicol acetyltransferase activity and hepatitis B surface antigen in liver and spleen. In addition, administration of genes coding for hormones (insulin or growth hormone) resulted in their expression.

  19. Effects of antibacterials use in aquaculture on biogeochemical processes in marine sediment.

    PubMed

    Ma, Deyi; Hu, Yingying; Wang, Juying; Ye, Sai; Li, Ai

    2006-08-15

    The effects of chloramphenicol on microorganism in marine sediment were studied by spiked experiments in this paper. The results showed that high concentrations of chloramphenicol could inhibit the activities of microorganism in sediment, and that the growth of strains Pseudomons and Acinetobacter in sediment that can degrade organic matters were inhibited apparently. Furthermore, the resistance of heterotrophic bacteria in sediment had developed due to the use of antibacterials. Based on the above results potential environmental effects of antibacterials on microorganism in marine sediment were analyzed.

  20. Antimicrobial resistance of Salmonella isolates in a Spanish hospital.

    PubMed Central

    Muńoz, P; Díaz, M D; Rodríguez-Créixems, M; Cercenado, E; Peláez, T; Bouza, E

    1993-01-01

    We studied 961 clinical Salmonella isolates (one per patient) seen in one Spanish hospital from 1988 to 1991. The incidence of non-Salmonella typhi Salmonella infections per 100,000 admissions increased from 3.93 to 5.98. Overall rates of resistance to ampicillin, chloramphenicol, and co-trimoxazole were 32, 11, and 2%, respectively. Resistance to chloramphenicol increased from 9 to 16% during the study period, while resistance to each of the other drugs remained stable. Variations related to serogroups were observed. PMID:8517717

  1. [Multi-resistant strains of Salmonella typhi in Spain].

    PubMed

    Usera, M A; Aladueña, A; Jaime, M L; Raya, C; Fuster, C; Planes, A; Bartolomé, R M

    1992-11-01

    Most Salmonella typhi isolated in Spain are susceptible to antibiotics commonly used in its treatment as chloramphenicol, ampicillin and cotrimoxazole. Three multiresistant strains have been isolated from different patients the last two years. Two phage type M1, biotype xylose tetrationate + strains were isolated from blood of two patients in Bembibre (León). One phage type E1a biotype xylose + tetrationate reductase + strain was isolated from blood and faeces of one patient in Barcelona. All strains harboured a 79 Mdal plasmid responsible for multiresistance, chloramphenicol acetyl transferase production and conjugative.

  2. A novel fexA variant from a canine Staphylococcus pseudintermedius isolate that does not confer florfenicol resistance.

    PubMed

    Gómez-Sanz, Elena; Kadlec, Kristina; Feßler, Andrea T; Zarazaga, Myriam; Torres, Carmen; Schwarz, Stefan

    2013-11-01

    Transposon Tn558 integrated in the chromosomal radC gene was detected for the first time in Staphylococus pseudintermedius. It carried a novel fexA variant (fexAv) that confers only chloramphenicol resistance. The exporter FexAv exhibited two amino acid substitutions, Gly33Ala and Ala37Val, both of which seem to be important for substrate recognition. Site-directed mutagenesis that reverted the mutated base pairs to those present in the original fexA gene restored the chloramphenicol-plus-florfenicol resistance phenotype.

  3. A Novel FexA Variant from a Canine Staphylococcus pseudintermedius Isolate That Does Not Confer Florfenicol Resistance

    PubMed Central

    Gómez-Sanz, Elena; Kadlec, Kristina; Feßler, Andrea T.; Zarazaga, Myriam; Schwarz, Stefan

    2013-01-01

    Transposon Tn558 integrated in the chromosomal radC gene was detected for the first time in Staphylococus pseudintermedius. It carried a novel fexA variant (fexAv) that confers only chloramphenicol resistance. The exporter FexAv exhibited two amino acid substitutions, Gly33Ala and Ala37Val, both of which seem to be important for substrate recognition. Site-directed mutagenesis that reverted the mutated base pairs to those present in the original fexA gene restored the chloramphenicol-plus-florfenicol resistance phenotype. PMID:23979755

  4. Status of Standardization Projects

    DTIC Science & Technology

    1992-09-30

    BUTETANIDE INJ MB DM F2 A 923 933 933 A MO MS 03 MB N 6505 5740 A-A-XXX CAPTOPRIL TABS MB DM F2 A 923 933 933 A MO MS 03 MB N 6505 5741 A-A-XXX CHLORAMPHENICOL...923 933 933 A MD MS 03 MB N 6505 5740 A-A-XXX CAPTOPRIL TABS MB DM F2 A 923 933 933 A MD MS 03 MB N 6505 5741 A-A-XXX CHLORAMPHENICOL OINT MB DM F2 A

  5. Antimicrobial susceptibilities of Erysipelothrix rhusiopathiae.

    PubMed Central

    Venditti, M; Gelfusa, V; Tarasi, A; Brandimarte, C; Serra, P

    1990-01-01

    The in vitro susceptibilities of 10 isolates of Erysipelothrix rhusiopathiae to 16 antimicrobial agents were determined. Penicillin and imipenem were the most active agents, followed by piperacillin, cefotaxime, ciprofloxacin, pefloxacin, and clindamycin. Some resistance was observed with erythromycin, tetracycline, and chloramphenicol. Activity was poor or absent with vancomycin, teicoplanin, daptomycin, trimethoprim-sulfamethoxazole, gentamicin, and netilmicin. PMID:2291674

  6. Temperature sensitivity of the penicillin-induced autolysis mechanism in nongrowing cultures of Escherichia coli.

    PubMed Central

    Kusser, W; Ishiguro, E E

    1987-01-01

    The effect of incubation temperature on the ampicillin-induced autolysis of nongrowing Escherichia coli was determined. The autolysis mechanisms in amino acid-deprived relA mutant cells treated with chloramphenicol were temperature sensitive. This temperature-sensitive autolysis was demonstrated in three independent ways: turbidimetric determinations, viable cell counts, and solubilization of radiolabeled peptidoglycan. PMID:3553163

  7. Ciprofloxacin does not inhibit mitochondrial functions but other antibiotics do.

    PubMed Central

    Riesbeck, K; Bredberg, A; Forsgren, A

    1990-01-01

    At clinical concentrations, ciprofloxacin did not inhibit mitochondrial DNA replication, oxidative phosphorylation, protein synthesis, or mitochondrial mass (transmembrane potential). No difference in supercoiled forms of DNA was observed. The tetracyclines and chloramphenicol inhibited protein synthesis at clinically achievable concentrations, while rifampin, fusidic acid, and clindamycin did not. PMID:2327755

  8. Limited effects of temafloxacin compared with ciprofloxacin on T-lymphocyte function.

    PubMed Central

    Riesbeck, K; Forsgren, A

    1994-01-01

    Temafloxacin increased interleukin-2 production and mRNA levels and enhanced thymidine incorporation in stimulated lymphocyte cultures. Gamma interferon mRNA levels were unaffected. Temafloxacin also stimulated interleukin-2 gene induction, as revealed in a chloramphenicol acetyltransferase reporter gene system. However, temafloxacin exerted significantly weaker effects in these respects than did ciprofloxacin. Images PMID:8031064

  9. Synthesis and biological activity of nifuroxazide and analogs.

    PubMed

    Tavares, L C; Penna, T C; Amaral, A T

    1997-03-01

    Nifuroxazide and thirteen analogs were synthesized from substituted benzoic acids and minimal inhibitory concentrations were determined using the serial dilution tests, in three sequential steps. Nifuroxazide and chloramphenicol were used as reference standards. The tests were performed in TSB against the standard bacterial strain of Staphylococcus aureus ATCC 25923.

  10. Antibiotics

    NASA Astrophysics Data System (ADS)

    Anhalt, John P.

    A 28-year-old man was transferred to our hospital and underwent surgery for resection of an aortic graft infected with Klebsiella pneumoniae. Antimicrobial therapy consisted of amikacin, cefazolin, chloramphenicol, sulfamethoxazole, and trimethoprim. A request for amikacin and sulfamethoxazole assays was received by the laboratory along with information that the patient had received tobramycin until 24 h before the serum was obtained.

  11. ACSSuT Multi-Drug Resistance Among Salmonella Isolates of Animal Origin

    USDA-ARS?s Scientific Manuscript database

    BACKGROUND: Multi-drug resistant (MDR) Salmonella Typhimurium DT104 (DT104) emerged in the mid-1990’s in humans and animals with infection resulting in increased morbidity and mortality. DT104 was characterized by resistance to Ampicillin, Chloramphenicol, Streptomycin, Sulfa, and Tetracycline (AC...

  12. Geraniol Restores Antibiotic Activities against Multidrug-Resistant Isolates from Gram-Negative Species▿ †

    PubMed Central

    Lorenzi, Vannina; Muselli, Alain; Bernardini, Antoine François; Berti, Liliane; Pagès, Jean-Marie; Amaral, Leonard; Bolla, Jean-Michel

    2009-01-01

    The essential oil of Helichrysum italicum significantly reduces the multidrug resistance of Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Combinations of the two most active fractions of the essential oil with each other or with phenylalanine arginine β-naphthylamide yield synergistic activity. Geraniol, a component of one fraction, significantly increased the efficacy of β-lactams, quinolones, and chloramphenicol. PMID:19258278

  13. Drug-susceptibility of isolates of Brachyspira hyodysenteriae isolated from colonic mucosal specimens of pigs collected from slaughter houses in Japan in 2009

    PubMed Central

    KAJIWARA, Keita; KOZAWA, Midori; KANAZAWA, Takuya; UETSUKA, Kouji; NAKAJIMA, Hiromi; ADACHI, Yoshikazu

    2015-01-01

    Twenty nine isolates identified as Brachyspira hyodysenteriae were most susceptible to carbadox and metronidazole, whereas they were resistant to macrolides. The isolates showed intermediate susceptibility to tiamulin, lincomycin, penicillin G, ampicillin, chloramphenicol, tetracycline, enrofloxacin and valnemulin, with MIC50 values ranging from 0.39 to 3.13. PMID:26596637

  14. Antimicrobial resistance profile of methicillin resistant staphylococcal aureus from skin and soft tissue isolates.

    PubMed

    Idrees, Faiza; Jabeen, Kauser; Khan, Muhammad Shoaib; Zafar, Afia

    2009-05-01

    To evaluate resistance rates in methicillin resistant Staphylococcus aureus (MRSA) against clindamycin, cotrimoxazole, tetracycline, fusidic acid, rifampicin and chloramphenicol isolated from skin and soft tissue infections (SSTI). Descriptive analysis of SSTI samples yielding MRSA in clinical laboratory of a tertiary care center; receiving specimens across Pakistan from January 2005 to June 2007. MICROBIOLOGICAL METHODS: MRSA were identified using standard microbiological techniques. Susceptibility testing was performed by disc diffusion according to Clinical Laboratory Standards Institute (CLSI) against fusidic acid, tetracycline, cotrimoxazole, clindamycin, rifampicin and chloramphenicol. Minimum inhibitory concentrations (MIC) of rifampicin were determined using agar dilution method according to CLSI. During the study period 501 MRSA were isolated from SSTI. Overall variable susceptibility pattern with high resistance rates to tetracycline (82%), clindamycin (79%), cotrimoxazole (59%), and rifampicin (50%) were observed. Resistance to chloramphenicol (10%) and fusidic acid (9%) was low. There is a strong need in resource limited countries to review the utility of conventional antibiotics for the management of MRSA SSTI as new agents are expensive and not available. High resistance rates were observed against cotrimoxazole, tetracycline and clindamycin. Resistance to fusidic acid, rifampicin and Chloramphenicol was low.

  15. Antimicrobial susceptibility to azithromycin among Salmonella enterica isolated from the United States

    USDA-ARS?s Scientific Manuscript database

    Due to emerging resistance to traditional antimicrobial agents such as ampicillin, trimethoprim-sulfamethoxazole and chloramphenicol, azithromycin is increasingly used for the treatment of invasive Salmonella infections. In the present study, 696 isolates of non-Typhi Salmonella collected from human...

  16. Genome engineering using a synthetic gene circuit in Bacillus subtilis

    PubMed Central

    Jeong, Da-Eun; Park, Seung-Hwan; Pan, Jae-Gu; Kim, Eui-Joong; Choi, Soo-Keun

    2015-01-01

    Genome engineering without leaving foreign DNA behind requires an efficient counter-selectable marker system. Here, we developed a genome engineering method in Bacillus subtilis using a synthetic gene circuit as a counter-selectable marker system. The system contained two repressible promoters (B. subtilis xylA (Pxyl) and spac (Pspac)) and two repressor genes (lacI and xylR). Pxyl-lacI was integrated into the B. subtilis genome with a target gene containing a desired mutation. The xylR and Pspac–chloramphenicol resistant genes (cat) were located on a helper plasmid. In the presence of xylose, repression of XylR by xylose induced LacI expression, the LacIs repressed the Pspac promoter and the cells become chloramphenicol sensitive. Thus, to survive in the presence of chloramphenicol, the cell must delete Pxyl-lacI by recombination between the wild-type and mutated target genes. The recombination leads to mutation of the target gene. The remaining helper plasmid was removed easily under the chloramphenicol absent condition. In this study, we showed base insertion, deletion and point mutation of the B. subtilis genome without leaving any foreign DNA behind. Additionally, we successfully deleted a 2-kb gene (amyE) and a 38-kb operon (ppsABCDE). This method will be useful to construct designer Bacillus strains for various industrial applications. PMID:25552415

  17. Bacteroides faecis and Bacteroides intestinalis recovered from clinical specimens of human intestinal origin.

    PubMed

    Lee, Yangsoon; Kim, Hyun Soo; Yong, Dongeun; Jeong, Seok Hoon; Lee, Kyungwon; Chong, Yunsop

    2015-01-01

    We report three cases of recently named Bacteroides spp. isolates, two B. faecis isolates and one B. intestinalis isolate from clinical specimens of inpatients at a Korean tertiary-care hospital in 2011. All isolates were susceptible to piperacillin-tazobactam, imipenem, meropenem, chloramphenicol, and metronidazole.

  18. In vitro and in vivo antibiotic susceptibilities of ELB rickettsiae.

    PubMed Central

    Radulovic, S; Higgins, J A; Jaworski, D C; Azad, A F

    1995-01-01

    The activities of doxycycline, rifampin, chloramphenicol, and erythromycin against ELB rickettsiae (Rickettsia azadi) were determined by dye uptake and plaque assays. Plaque formation in Vero cells was inhibited by 0.12 microgram of doxycycline per ml. The data presented demonstrate the susceptibility of ELB rickettsiae to commonly used antibiotics for the treatment of rickettsial diseases. PMID:8585746

  19. Studies on antibacterial activity of Ficus racemosa Linn. leaf extract.

    PubMed

    Mandal, S C; Saha, B P; Pal, M

    2000-06-01

    Extracts of Ficus racemosa Linn. leaves were tested for antibacterial potential against Escherichia coli ATCC 10536, Basillus pumilis ATCC 14884, Bacillus subtilis ATCC 6633, Pseudomonas aeruginosa ATCC 25619 and Staphylococcus aureus ATCC 29737. The effects produced by the extracts were significant and were compared with chloramphenicol. The petroleum ether extract was the most effective against the tested organisms.

  20. Chemotherapy of Bacterial Plasmids

    DTIC Science & Technology

    1979-01-29

    multiresistance to chemotherapeutic drugs, mediated drug resistance are the emergence of strains determined by R-plasmids, causes treatment failures of Haemophilus ... influenzae , resistant to ampicillin [8] of hospital infections, foremost in patients with a or chloramphenicol [9] and of Neisseria gonorrhoeae

  1. Failure of vancomycin treatment for meningitis caused by vancomycin-susceptible Enterococcus faecium.

    PubMed

    van Overbeek, Ellen C; Janknegt, Rob; Ter Berg, Hans W M; Top, Janetta; Sportel, Esther; Heddema, Edou R

    2010-10-01

    This case report describes a nosocomial vancomycin-sensitive Enterococcus faecium meningitis with poor response to vancomycin. E. faecium infections continue to represent a therapeutic challenge in Europe, even in countries where vancomycin resistance is still rare. In the case of vancomycin-sensitive E. faecium meningitis, intravenous chloramphenicol should be considered as a treatment option.

  2. ANTIBACTERIAL STUDIES ON LEAF EXTRACT OF ELEPHANTOPUS SCABER Linn

    PubMed Central

    Kumar, S. Suresh; Perumal, P.; Suresh, B.

    2004-01-01

    Methanolic extract of Elephantopus scaber Linn was investigated for its antibacterial activity against Staphylococcus aureus (NCIM – 2079), Escherichia coli (NCIM-2067), Bacillus subtilis (NCIM-2063), Pseudomonas aeruginosa (NCIM-2036), Proteus vulgaris (NCIM-2027) at 100 μg/disc by using disc diffusion method. The extract showed significant anti bacterial activity and were compared to chloramphenicol (30 μg/disc). PMID:22557125

  3. Genome engineering using a synthetic gene circuit in Bacillus subtilis.

    PubMed

    Jeong, Da-Eun; Park, Seung-Hwan; Pan, Jae-Gu; Kim, Eui-Joong; Choi, Soo-Keun

    2015-03-31

    Genome engineering without leaving foreign DNA behind requires an efficient counter-selectable marker system. Here, we developed a genome engineering method in Bacillus subtilis using a synthetic gene circuit as a counter-selectable marker system. The system contained two repressible promoters (B. subtilis xylA (Pxyl) and spac (Pspac)) and two repressor genes (lacI and xylR). Pxyl-lacI was integrated into the B. subtilis genome with a target gene containing a desired mutation. The xylR and Pspac-chloramphenicol resistant genes (cat) were located on a helper plasmid. In the presence of xylose, repression of XylR by xylose induced LacI expression, the LacIs repressed the Pspac promoter and the cells become chloramphenicol sensitive. Thus, to survive in the presence of chloramphenicol, the cell must delete Pxyl-lacI by recombination between the wild-type and mutated target genes. The recombination leads to mutation of the target gene. The remaining helper plasmid was removed easily under the chloramphenicol absent condition. In this study, we showed base insertion, deletion and point mutation of the B. subtilis genome without leaving any foreign DNA behind. Additionally, we successfully deleted a 2-kb gene (amyE) and a 38-kb operon (ppsABCDE). This method will be useful to construct designer Bacillus strains for various industrial applications.

  4. [Side effects of antibiotics].

    PubMed

    Hoigné, R

    1975-03-01

    The clinically severe and newer forms of antibiotic side effects are reviewed. The study covers the following antibiotics: penicillins, cephalosporins, aminoglycosides and polymyxins, tetracyclines, chloramphenicol and thiamphenicol, macrolides and lincomycin, rifamycins and sulfonamides. Special reference is made to (1) hematologic side effects, and (2) general evaluation of drug reactions. The relationship between reaction time and clinical symptoms is of particular practical significance.

  5. Inactivation of Penicillins by Thiol Broth

    PubMed Central

    Murray, Patrick R.; Niles, Ann C.

    1982-01-01

    Thiol broth with sodium polyanetholesulfonate inactivated penicillin G, carbenicillin, nafcillin, oxacillin, and gentamicin, but had no effect on cephalothin, cefoxitin, clindamycin, chloramphenicol, erythromycin, and tetracycline. Only Thiol broth was capable of this inactivation, which was not influenced by the presence of blood. PMID:7153352

  6. Lethal action of quinolones against a temperature-sensitive dnaB replication mutant of Escherichia coli.

    PubMed

    Zhao, Xilin; Malik, Muhammad; Chan, Nymph; Drlica-Wagner, Alex; Wang, Jian-Ying; Li, Xinying; Drlica, Karl

    2006-01-01

    Inhibition of DNA replication in an Escherichia coli dnaB-22 mutant failed to block quinolone-mediated lethality. Inhibition of protein synthesis by chloramphenicol inhibited nalidixic acid lethality and, to a lesser extent, ciprofloxacin lethality in both dnaB-22 and wild-type cells. Thus, major features of quinolone-mediated lethality do not depend on ongoing replication.

  7. An In Vitro Study on the Effects of Nisin on the Antibacterial Activities of 18 Antibiotics against Enterococcus faecalis

    PubMed Central

    Ling, Junqi; Ma, Jinglei; Huang, Lijia; Zhang, Luodan

    2014-01-01

    Enterococcus faecalis rank among the leading causes of nosocomial infections worldwide and possesses both intrinsic and acquired resistance to a variety of antibiotics. Development of new antibiotics is limited, and pathogens continually generate new antibiotic resistance. Many researchers aim to identify strategies to effectively kill this drug-resistant pathogen. Here, we evaluated the effect of the antimicrobial peptide nisin on the antibacterial activities of 18 antibiotics against E. faecalis. The MIC and MBC results showed that the antibacterial activities of 18 antibiotics against E. faecalis OG1RF, ATCC 29212, and strain E were significantly improved in the presence of 200 U/ml nisin. Statistically significant differences were observed between the results with and without 200 U/ml nisin at the same concentrations of penicillin or chloramphenicol (p<0.05). The checkerboard assay showed that the combination of nisin and penicillin or chloramphenicol had a synergetic effect against the three tested E. faecalis strains. The transmission electron microscope images showed that E. faecalis was not obviously destroyed by penicillin or chloramphenicol alone but was severely disrupted by either antibiotic in combination with nisin. Furthermore, assessing biofilms by a confocal laser scanning microscope showed that penicillin, ciprofloxacin, and chloramphenicol all showed stronger antibiofilm actions in combination with nisin than when these antibiotics were administered alone. Therefore, nisin can significantly improve the antibacterial and antibiofilm activities of many antibiotics, and certain antibiotics in combination with nisin have considerable potential for use as inhibitors of this drug-resistant pathogen. PMID:24586598

  8. Diagnosis, Treatment, and Prevention of Malaria

    DTIC Science & Technology

    1992-11-01

    Precautions. Candida vaginitis is a troubling and common side effect. Photosensitivity reactions are much less common, and esophageal ulcerations are a rare...crosses into CSF: chloramphenicol or third generation cephalosporin A parenteral antiemetic Bladder catheters Nurses trained to measure vital signs, input...in the evening. Doxycycline use can also be associated with Candida infections, especially vaginitis , nausea, vomiting, and diarrhea. Pyrimethamine

  9. Fabrication of SERS-active substrates using silver nanofilm-coated porous anodic aluminum oxide for detection of antibiotics.

    PubMed

    Chen, Jing; Feng, Shaolong; Gao, Fang; Grant, Edward; Xu, Jie; Wang, Shuo; Huang, Qian; Lu, Xiaonan

    2015-04-01

    We have developed a silver nanofilm-coated porous anodic aluminum oxide (AAO) as a surface-enhanced Raman scattering (SERS)-active substrate for the detection of trace level of chloramphenicol, a representative antibiotic in food systems. The ordered aluminum template generated during the synthesis of AAO serves as a patterned matrix on which a coated silver film replicates the patterned AAO matrix to form a 2-dimensional ordered nanostructure. We used atomic force microscopy and scanning electron microscopy images to determine the morphology of this nanosubstrate, and characterized its localized surface plasmon resonance by ultraviolet-visible reflection. We gauged the SERS effect of this nanosubstrate by confocal micro-Raman spectroscopy (782-nm laser), finding a satisfactory and consistent performance with enhancement factors of approximately 2 × 10(4) and a limit of detection for chloramphenicol of 7.5 ppb. We applied principal component analysis to determine the limit of quantification for chloramphenicol of 10 ppb. Using electromagnetic field theory, we developed a detailed mathematical model to explain the mechanism of Raman signal enhancement of this nanosubstrate. With simple sample pretreatment and separation steps, this silver nanofilm-coated AAO substrate could detect 50 ppb chloramphenicol in milk, indicating good potential as a reliable SERS-active substrate for rapid detection of chemical contaminants in agricultural and food products.

  10. [Annual review of serotypes of E. coli isolated from various lesions in poultry and their sensitivity to drugs in vitro (author's transl)].

    PubMed

    Goren, E

    1976-05-15

    550 Strains of E. coli, isolated from poultry, were typed. In addition, their sensitivity to various drugs was tested. A wide variety of serotypes was found to be present. Approximately 50% of the isolated strains of E. coli were found to be resistant to the tetracyclines, streptomycin and sulphafurazole. Chloramphenicol, neomycin and furazolidone usually were effective.

  11. The identification of antibacterial compounds for the development of enhanced media for the detection of foodborne fungi.

    PubMed

    Tournas, V H; Kohn, J S; Katsoudas, E J

    2007-08-15

    In an effort to identify a more suitable antibiotic for utilization in mycological media, 12 food borne fungal species from various genera including Alternaria alternata, Aspergillus flavus, A. niger, Eurotium chevalieri, Fusarium moniliforme, Penicillium sp., Rhizopus stolonifer, Saccharomyces cerevisiae, Candida tropicalis, Geotrichum candidum, Rhodotorula glutinis and Kluyveromyces thermotolerans along with 21 chloramphenicol-resistant bacterial isolates from fresh produce and ATCC cultures of Pseudomonas aeruginosa, P. fluorescens, E. coli, Pectobacterium carotovorum, Bacillus cereus and Staphylococcus spp. were tested for their abilities to grow on dichloran rose bengal agar containing various levels of gentamicin, chlortetracycline or chloramphenicol. Results indicated that all fungal isolates except for Rh. glutinis and R. stolonifer grew well on all media tested. Rh. glutinis did not grow on media containing gentamicin whereas R. stolonifer produced very restricted or no growth on these media. All bacterial isolates from fresh produce, P. aeruginosa (ATCC 27853) and P. fluorescens (ATCC BAA-477) grew well at 100, 125 and 150 mg chloramphenicol/liter medium, but they did not grow on media containing chlortetracycline (100, 125, or 150 mg/L) or gentamicin (15, 25, or 35 mg/L). P. aeruginosa (ATCC 10145) grew well on media containing chloramphenicol or gentamicin, but not in the presence of chlortetracycline. P. carotovorum, E. coli, B. cereus and Staphylococcus spp. did not grow on any of the selective media tested.

  12. Transformation of the Cyanidioschyzon merolae chloroplast genome: prospects for understanding chloroplast function in extreme environments.

    PubMed

    Zienkiewicz, Maksymilian; Krupnik, Tomasz; Drożak, Anna; Golke, Anna; Romanowska, Elżbieta

    2017-01-01

    We have successfully transformed an exthemophilic red alga with the chloramphenicol acetyltransferase gene, rendering this organism insensitive to its toxicity. Our work paves the way to further work with this new modelorganism. Here we report the first successful attempt to achieve a stable, under selectable pressure, chloroplast transformation in Cyanidioschizon merolae-an extremophilic red alga of increasing importance as a new model organism. The following protocol takes advantage of a double homologous recombination phenomenon in the chloroplast, allowing to introduce an exogenous, selectable gene. For that purpose, we decided to use chloramphenicol acetyltransferase (CAT), as chloroplasts are particularly vulnerable to chloramphenicol lethal effects (Zienkiewicz et al. in Protoplasma, 2015, doi: 10.1007/s00709-015-0936-9 ). We adjusted two methods of DNA delivery: the PEG-mediated delivery and the biolistic bombardment based delivery, either of these methods work sufficiently with noticeable preference to the former. Application of a codon-optimized sequence of the cat gene and a single colony selection yielded C. merolae strains, capable of resisting up to 400 µg/mL of chloramphenicol. Our method opens new possibilities in production of site-directed mutants, recombinant proteins and exogenous protein overexpression in C. merolae-a new model organism.

  13. Susceptibility of Escherichia coli isolated from uteri of postpartum dairy cows to antibiotic and environmental bacteriophages. Part II: In vitro antimicrobial activity evaluation of a bacteriophage cocktail and several antibiotics.

    PubMed

    Santos, T M A; Gilbert, R O; Caixeta, L S; Machado, V S; Teixeira, L M; Bicalho, R C

    2010-01-01

    The use of pathogenic-specific antimicrobials, as proposed by bacteriophage therapy, is expected to reduce the incidence of resistance development. Eighty Escherichia coli isolated from uteri of Holstein dairy cows were phenotypically characterized for antimicrobial resistance to ampicillin, ceftiofur, chloramphenicol, florfenicol, spectinomycin, streptomycin, and tetracycline by broth microdilution method. The lytic activity of a bacteriophage cocktail against all isolates was performed by a similar method. Additionally, the effect of different concentrations of antimicrobials and multiplicities of infections (MOI) of the bacteriophage cocktail on E. coli growth curve was measured. Isolates exhibited resistance to ampicillin (33.7%), ceftiofur (1.2%), chloramphenicol (100%), and florfenicol (100%). All strains were resistant to at least 2 of the antimicrobial agents tested; multidrug resistance (>or=3 of 7 antimicrobials tested) was observed in 35% of E. coli isolates. The major multidrug resistance profile was found for ampicillin-chloramphenicol-florfenicol, which was observed in more than 96.4% of the multidrug-resistant isolates. The bacteriophage cocktail preparation showed strong antimicrobial activity against multidrug-resistant E. coli. Multiplicity of infection as low as 10(-4) affected the growth of the E. coli isolates. The ratio of 10 bacteriophage particles per bacterial cell (MOI=10(1)) was efficient in inhibiting at least 50% of all isolates. Higher MOI should be tested in future in vitro studies to establish ratios that completely inhibit bacterial growth during longer periods. All isolates resistant to florfenicol were resistant to chloramphenicol and, because florfenicol was recently introduced into veterinary clinics, this finding suggests that the selection pressure of chloramphenicol, as well as other antimicrobials, may still play a relevant role in the emergence and dissemination of florfenicol resistance in E. coli. The bacteriophage

  14. Unique plasmids generated via pUC replicon mutagenesis in an error-prone thermophile derived from Geobacillus kaustophilus HTA426.

    PubMed

    Kobayashi, Jyumpei; Tanabiki, Misaki; Doi, Shohei; Kondo, Akihiko; Ohshiro, Takashi; Suzuki, Hirokazu

    2015-11-01

    The plasmid pGKE75-catA138T, which comprises pUC18 and the catA138T gene encoding thermostable chloramphenicol acetyltransferase with an A138T amino acid replacement (CATA138T), serves as an Escherichia coli-Geobacillus kaustophilus shuttle plasmid that confers moderate chloramphenicol resistance on G. kaustophilus HTA426. The present study examined the thermoadaptation-directed mutagenesis of pGKE75-catA138T in an error-prone thermophile, generating the mutant plasmid pGKE75(αβ)-catA138T responsible for substantial chloramphenicol resistance at 65°C. pGKE75(αβ)-catA138T contained no mutation in the catA138T gene but had two mutations in the pUC replicon, even though the replicon has no apparent role in G. kaustophilus. Biochemical characterization suggested that the efficient chloramphenicol resistance conferred by pGKE75(αβ)-catA138T is attributable to increases in intracellular CATA138T and acetyl-coenzyme A following a decrease in incomplete forms of pGKE75(αβ)-catA138T. The decrease in incomplete plasmids may be due to optimization of plasmid replication by RNA species transcribed from the mutant pUC replicon, which were actually produced in G. kaustophilus. It is noteworthy that G. kaustophilus was transformed with pGKE75(αβ)-catA138T using chloramphenicol selection at 60°C. In addition, a pUC18 derivative with the two mutations propagated in E. coli at a high copy number independently of the culture temperature and high plasmid stability. Since these properties have not been observed in known plasmids, the outcomes extend the genetic toolboxes for G. kaustophilus and E. coli. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  15. Elimination of the amphibian chytrid fungus Batrachochytrium dendrobatidis by Archey's frog Leiopelma archeyi.

    PubMed

    Bishop, Phillip J; Speare, Rick; Poulter, Russell; Butler, Margi; Speare, Benjamin J; Hyatt, Alex; Olsen, Veronica; Haigh, Amanda

    2009-03-09

    Archey's frog Leiopelma archeyi is a critically endangered New Zealand endemic species. The discovery of the emerging infectious disease, chytridiomycosis, in wild populations of this frog raised concern that this disease may drive the species to extinction. Twelve wild-caught Archey's frogs naturally infected with the amphibian chytrid fungus Batrachochytrium dendrobatidis were monitored in captivity by observing clinical signs, measuring weight gain, and performing repeated PCR tests. Eight frogs were treated with topical chloramphenicol, without PCR results being available, for B. dendrobatidis at the day of entry of the frog into the trial. Eleven of the 12 frogs (92%) cleared their infection within 3 mo of capture, even though they were held at 15 degrees C and in high humidity, conditions that are ideal for the survival and propagation of B. dendrobatidis. B. dendrobatidis in the remaining frog tested positive for the fungus was eliminated after treatment with topical chloramphenicol. None of the 8 frogs exposed to chloramphenicol showed any acute adverse reactions. Archey's frog appears to have a low level of susceptibility to the clinical effects of chytridiomycosis. Individual frogs can eliminate B. dendrobatidis and Archey's frog can apparently be treated with topical chloramphenicol with no acute adverse reactions. However, the small number of specimens treated here requires that more extensive testing be done to confirm the safety of chloramphenicol. The significance of the amphibian chytrid fungus for wild populations of Archey's frog needs to be determined by a longitudinal study in an infected wild population to correlate the presence of B. dendrobatidis in individual frogs. Such a study should occur over a period of at least 3 yr with clinical assessment and monitoring of survival, growth and body condition parameters.

  16. Identification of a Novel G2073A Mutation in 23S rRNA in Amphenicol-Selected Mutants of Campylobacter jejuni

    PubMed Central

    Naren, Gaowa; Li, Hui; Xia, Xi; Wu, Congming; Shen, Jianzhong; Zhang, Qijing; Wang, Yang

    2014-01-01

    Objectives This study was conducted to examine the development and molecular mechanisms of amphenicol resistance in Campylobacter jejuni by using in vitro selection with chloramphenicol and florfenicol. The impact of the resistance development on growth rates was also determined using in vitro culture. Methods Chloramphenicol and florfenicol were used as selection agents to perform in vitro stepwise selection. Mutants resistant to the selective agents were obtained from the selection process. The mutant strains were compared with the parent strain for changes in MICs and growth rates. The 23S rRNA gene and the L4 and L22 ribosomal protein genes in the mutant strains and the parent strain were amplified and sequenced to identify potential resistance-associated mutations. Results C. jejuni strains that were highly resistant to chloramphenicol and florfenicol were obtained from in vitro selection. A novel G2073A mutation in all three copies of the 23S rRNA gene was identified in all the resistant mutants examined, which showed resistance to both chloramphenicol and florfenicol. In addition, all the mutants selected by chloramphenicol also exhibited the G74D modification in ribosomal protein L4, which was previously shown to confer a low-level erythromycin resistance in Campylobacter species. The mutants selected by florfenicol did not have the G74D mutation in L4. Notably, the amphenicol-resistant mutants also exhibited reduced susceptibility to erythromycin, suggesting that the selection resulted in cross resistance to macrolides. Conclusions This study identifies a novel point mutation (G2073A) in 23S rRNA in amphenicol-selected mutants of C. jejuni. Development of amphenicol resistance in Campylobacter likely incurs a fitness cost as the mutant strains showed slower growth rates in antibiotic-free media. PMID:24728007

  17. Antibiotic resistance monitoring in heterotrophic bacteria from anthropogenic-polluted seawater and the intestines of oyster Crassostrea hongkongensis.

    PubMed

    Wang, Rui Xuan; Wang, AnLi; Wang, Jiang Yong

    2014-11-01

    A total of 1,050 strains of heterotrophic bacteria isolated from farming seawater and the intestines of oyster species Crassostrea hongkongensis were tested for resistance to 10 antibiotics by the Kirby-Bauer diffusion method. The resistant rates of seawater-derived bacteria to chloramphenicol, enrofloxacin, and ciprofloxacin were low (less than 20%), whereas the bacteria obtained from oysters showed low resistance to chloramphenicol and enrofloxacin. Many strains showed high resistant rates (more than 40%) to furazolidone, penicillin G, and rifampin. A total of 285 strains from farming seawater and oysters were resistant to more than three antibiotics. Several strains showed resistance to more than nine antibiotics. Furthermore, the peak resistant rates of the seawater-derived strains to multiple antibiotics overlapped in April, June, September, and November, and those of oyster-derived strains overlapped during April, July, and September. The multi-resistant rate patterns of strains from farming seawater and oyster intestines were similar.

  18. Eco-friendly synthesis and in vitro antibacterial activities of some novel chalcones.

    PubMed

    Khan, Salman A; Asiri, Abdullah M; Alamry, Khalid A; El-Daly, Samy A; Zayed, Mohie A M

    2013-01-01

    Chalcone derivatives have been synthesized by reaction of 1-(2,5-dimethyl-furan-3-yl)-ethanone with corresponding active aldehyde in ethanolic NaOH in microwave oven. The structure of these compounds was established by elemental analysis, IR, 1H-NMR, 13C-NMR, and EI-MS spectral analysis. The anti-bacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined with the reference of standard drug Chloramphenicol. The results showed that pyrazol containing chalcone (compound 8) inhibited both types of bacteria (Gram-positive and Gram-negative) better than chloramphenicol.

  19. [Rocky Mountain spotted fever in Brazil].

    PubMed

    del Sá DelFiol, Fernando; Junqueira, Fábio Miranda; da Rocha, Maria Carolina Pereira; de Toledo, Maria Inês; Filho, Silvio Barberato

    2010-06-01

    Although the number of confirmed cases of spotted fever has been declining in Brazil since 2005, the mortality rate (20% to 30%) is still high in comparison to other countries. This high mortality rate is closely related to the difficulty in making the diagnosis and starting the correct treatment. Only two groups of antibiotics have proven clinical effectiveness against spotted fever: chloramphenicol and tetracyclines. Until recently, the use of tetracyclines was restricted to adults because of the associated bone and tooth changes in children. Recently, however, the American Academy of Pediatrics and various researchers have recommended the use of doxycycline in children. In more severe cases, chloramphenicol injections are often preferred in Brazil because of the lack of experience with injectable tetracycline. Since early diagnosis and the adequate drug treatment are key to a good prognosis, health care professionals must be better prepared to recognize and treat spotted fever.

  20. Purification and characterization of a 4-hydroxybiphenyl UDP-glucuronosyltransferase from rat liver microsomes

    SciTech Connect

    Styczynski, B.; Green, M.; Coffman, B.; Puig, J.; Tephly, T. )

    1991-03-11

    A phenobarbital-inducible rat liver microsomal UDP-glucuronosyltransferase (4-HBP UDPGT) which catalyzes the glucuronidation of 4-hydroxybiphenyl has been purified to homogeneity. The apparent subunit molecular weight of this protein is 52,500 as determined by SDS-PAGE. 4-HBP UDPGT was shown to react with 4-hydroxybiphenyl, p-nitrophenol and 4-methylumbelliferone, but did not react with morphine, testosteron or chloramphenicol. Upon treatment with Endoglycosidase H, the 4-HBP UDPGT underwent about a 2,000 dalton decrease in subunit molecular weight, suggesting that this protein in N-glycosylated. Western blot analysis has revealed immunorecognition of 4-HBP UDPGT by antibodies raised in rabbit against rat 3{alpha}- and 17{beta}-hydroxysteroid UDPGTs. Additionally, the authors have obtained the N-terminal amino acid sequence of 4-HBP UDPGT. These data provide evidence which suggests that this protein is different from another UDPGT previously shown to react with 4-hydroxybiphenyl, testosterone and chloramphenicol.

  1. A Novel Method for Preparation of Gold NanoBipyramids Using Microwave Irradiation and Its Application in Immunosensors

    NASA Astrophysics Data System (ADS)

    Huynh, Trong Phat; Ngo, Vo Ke Thanh; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Nghiem, Quoc Dat; Lam, Quang Vinh; Huynh, Thanh Dat

    2016-05-01

    Gold nanobipyramids (NBPs) have attracted attention for producing smart sensing devices as diagnostic tools in biotechnological and medical applications, because they show more advantageous plasmonic properties than comparable gold nanorods. Normally, NBPs were synthesized using seed-mediated growth process at room temperature. In this report, our group describes a method for synthesising of NBPs using microwave irradiation with ascorbic acid reduction and cetyltrimethylammonium bromide + silver nitrate (AgNO3) as capping agents. The advantages of this method are a highly effective approach to fast and uniform NBPs. The product was characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and x-ray powder diffraction. As an application in quartz crystal microbalance immunosensors, NBPs is conjugated with the chloramphenicol antibodies for signal amplification to detect chloramphenicol residuals in the QCM system.

  2. Correlation Between the Rate of Ribonucleic Acid Synthesis and the Level of Valyl Transfer Ribonucleic Acid in Mutants of Escherichia coli

    PubMed Central

    Kaplan, Sam

    1969-01-01

    By use of a mutant of Escherichia coli with a partially thermolabile transfer ribonucleic acid (tRNA) synthase, it was possible to regulate the rate of RNA synthesis over a 10-fold range. The addition of chloramphenicol to cultures kept at the nonpermissive temperature stimulated RNA synthesis. The longer the culture was kept at the nonpermissive temperature prior to addition of chloramphenicol, the lower was the resulting rate of RNA synthesis. The decrease in the rate of incorporation of labeled uracil into RNA was correlated with the decrease in the level of valyl tRNA. Additional experiments provided evidence which may be interpreted as indicating that valyl tRNA does not, by itself, react with the RNA-forming system. PMID:4891259

  3. Low level of cross-resistance between triclosan and antibiotics in Escherichia coli K-12 and E. coli O55 compared to E. coli O157.

    PubMed

    Braoudaki, Maria; Hilton, Anthony Craig

    2004-06-15

    Misuse of biocides has encouraged the emergence of resistance and cross-resistance in certain strains. This study investigated resistance of triclosan-adapted Escherichia coli K-12 and E. coli O55 to antimicrobial agents and compared these to E. coli O157:H7. Cross-resistance in E. coli K-12 and E. coli O55 was observed however to a lesser extent than in E. coli O157:H7. Triclosan-adapted E. coli K-12 demonstrated cross-resistance to chloramphenicol, whereas triclosan-adapted E. coli O55 exhibited resistance to trimethoprim. In comparison, E. coli O157:H7 was resistant to chloramphenicol, tetracycline, amoxicillin, amoxicillin/clavulanic acid, trimethoprim, benzalkonium chloride and chlorohexidine suggesting strain specific rather than general resistance mechanisms.

  4. The In Vitro Antimicrobial Effects of Lavandula angustifolia Essential Oil in Combination with Conventional Antimicrobial Agents

    PubMed Central

    de Rapper, Stephanie; Viljoen, Alvaro

    2016-01-01

    The paper focuses on the in vitro antimicrobial activity of Lavandula angustifolia Mill. (lavender) essential oil in combination with four commercial antimicrobial agents. Stock solutions of chloramphenicol, ciprofloxacin, nystatin, and fusidic acid were tested in combination with L. angustifolia essential oil. The antimicrobial activities of the combinations were investigated against the Gram-positive bacterial strain Staphylococcus aureus (ATCC 6538) and Gram-negative Pseudomonas aeruginosa (ATCC 27858) and Candida albicans (ATCC 10231) was selected to represent the yeasts. The antimicrobial effect was performed using the minimum inhibitory concentration (MIC) microdilution assay. Isobolograms were constructed for varying ratios. The most prominent interaction was noted when L. angustifolia essential oil was combined with chloramphenicol and tested against the pathogen P. aeruginosa (ΣFIC of 0.29). Lavendula angustifolia essential oil was shown in most cases to interact synergistically with conventional antimicrobials when combined in ratios where higher volumes of L. angustifolia essential oil were incorporated into the combination. PMID:27891157

  5. A radiometric method for predicting effectiveness of chemotherapeutic agents in murine leprosy.

    PubMed

    Camargo, E E; Larson, S M; Tepper, B S; Wagner, H N

    1975-01-01

    A simple radiometric method has been developed for evaluating the effect of drugs on the metabolism of M. lepraemurium. The method is based on the measurement of the 14CO2 produced through bacterial metabolism of acetate-U-14C. Seventeen drugs were tested: bacitracin, cephaloridine, chloramphenicol, cycloserine, dactinomycin, DDS, ethionamide, INH, kanamycin, methenamine mandelate, nitrofurantoin, oxacillin, polymyxin B, rifampicin, streptomycin, sulfadimethoxine and vancomycin. The drugs which caused most marked inhibition were chloramphenicol, INH, ethionamide and nitrofurantoin in order of increasing effectiveness. The radiometric study which is completed in 15 days permits direct study of the drug effect on the metabolism of M. lepraemurium and a more rapid screening of antileprosy drugs than has previously been possible. Currently, these observations are being extended to studies of the structure-activity relationships of antileprosy drugs and the metabolism and drug susceptibility of M. leprae in vitro.

  6. Effects of UV light disinfection on antibiotic-resistant coliforms in wastewater effluents

    SciTech Connect

    Meckes, M.C.

    1982-02-01

    Total coliforms and total coliforms resistant to streptomycin, tetracycline, or chloramphenicol were isolated from filtered activated sludge effluents before and after UV light irradiation. Although the UV irradiation effectively disinfected the wastewater effluent, the percentage of the total surviving coliform population resistant to tetracycline or chloramphenicol was significantly higher than the percentage of the total coliform population resistant to those antibiotics before UV irradiation. This finding was attributed to the mechanism of R-factor mediated resistance to tetracycline. No significant difference was noted for the percentage of the surviving total coliform population resistant to streptomycin before or after UV irradiation. Multiple drug resistant to patterns of 300 total coliform isolates revealed that 82% were resistant to two or more antibiotics. Furthermore, 46% of these isolates were capable of transferring antibiotic resistance to a sensitive strain of Escherichia coli.

  7. Messenger Ribonucleic Acid Synthesis and Degradation in Escherichia coli During Inhibition of Translation

    PubMed Central

    Pato, Martin L.; Bennett, Peter M.; Von Meyenburg, Kaspar

    1973-01-01

    Various aspects of the coupling between the movement of ribosomes along messenger ribonucleic acids (mRNA) and the synthesis and degradation of mRNA have been investigated. Decreasing the rate of movement of ribosomes along an mRNA does not affect the rate of movement of some, and possibly most, of the RNA polymerases transcribing the gene coding for that mRNA. Inhibiting translation with antibiotics such as chloramphenicol, tetracycline, or fusidic acid protects extant mRNA from degradation, presumably by immobilizing ribosomes, whereas puromycin exposes mRNA to more rapid degradation than normal. The promoter distal (3′) portion of mRNA, synthesized after ribosomes have been immobilized by chloramphenicol on the promoter proximal (5′) portion of the mRNA, is subsequently degraded. PMID:4583248

  8. Synthesis, Characterization, Electrochemical Studies, and In Vitro Antibacterial Activity of Novel Thiosemicarbazone and Its Cu(II), Ni(II), and Co(II) Complexes

    PubMed Central

    Khan, Salman A.; Asiri, Abdullah M.; Al-Amry, Khalid; Malik, Maqsood Ahmad

    2014-01-01

    Metal complexes were prepared by the reaction of thiosemicarbazone with CuCl2, NiCl2, CoCl2, Cu(OAc)2, Ni(OAc)2, and Co(OAc)2. The thiosemicarbazone coordinates to metal through the thionic sulfur and the azomethine nitrogen. The thiosemicarbazone was obtained by the thiosemicarbazide with 3-acetyl-2,5-dimethylthiophene. The identities of these compounds were elucidated by IR, 1H, 13C-NMR, and GC-MS spectroscopic methods and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined by using chloramphenicol as reference drug. The results showed that compound 1.1 is better inhibitor of both types of tested bacteria as compared to chloramphenicol. PMID:24523641

  9. Emergence of tetracycline resistance due to a multiple drug resistance plasmid in Vibrio cholerae O139.

    PubMed

    Yamamoto, T; Nair, G B; Takeda, Y

    1995-04-01

    Of the 173 clinical strains of Vibrio cholerae O139 isolated from India, Bangladesh, and Thailand tested, six strains from India were resistant to tetracycline, ampicillin, chloramphenicol, kanamycin, and gentamicin. These six strains harbored a self-transmissible plasmid that mediated resistance to tetracycline, ampicillin, chloramphenicol, kanamycin, gentamicin, sulfamethoxazole, trimethoprim, and O/129. The multiple drug resistance plasmids were 200 kb in size and belonged to the incompatibility group C. Although a majority of the O139 strains (94.8%) were highly resistant to streptomycin, sulfamethoxazole, trimethoprim, and O/129, the tetracycline-susceptible strains so far tested were plasmid-negative. The data suggest the existence of two distinct multiple antimicrobial agent resistance (MAR) patterns in V. cholerae O139.

  10. Antibiotic sensitivity patterns among Indian strains of avian Pasteurella multocida.

    PubMed

    Shivachandra, S B; Kumar, A A; Biswas, A; Ramakrishnan, M A; Singh, Vijendra P; Srivastava, S K

    2004-11-01

    An investigation was carried out to study the antibiotic sensitivity of avian strains of Pasteurella multocida and to select an effective antimicrobial agent for control of avian pasteurellosis in India. A total of 123 strains of P. multocida recently isolated from different avian species (chicken, duck, turkey, quail, and goose), from different regions of India were subjected to antibiotic sensitivity tests using 20 different antibiotics. Absolute resistance was observed against sulfadiazine. The studies indicated that the strains were most sensitive to chloramphenicol (73.98%), followed by enrofloxacin (71.54%), lincomycin (64.23%), norfloxacin (61.79%) and doxycycline-HCl (56.91%). The majority of the strains were found to exhibit intermediate sensitivity. Chloramphenicol was selected and suggested for treatment. Antibiogram studies also revealed the emergence of multidrug-resistant strains of P. multocida among Indian poultry.

  11. In vitro susceptibility of Ehrlichia sennetsu to antibiotics.

    PubMed Central

    Brouqui, P; Raoult, D

    1990-01-01

    Antibiotic efficacies were evaluated by Diff-Quik (Dade, Düdingen, Federal Republic of Germany) staining of Ehrlichia sennetsu in P388D1 murine macrophages grown in 96-well microtiter plates. Sennetsu disease is generally cured with tetracyclines. In vivo, E. sennetsu is susceptible to doxycycline and is resistant to erythromycin, penicillin, and chloramphenicol. Our study confirmed, in vitro, the efficacy of doxycycline, which had an MIC of 0.125 micrograms/ml. E. sennetsu was found to be resistant to erythromycin, chloramphenicol, penicillin, gentamicin, and co-trimoxazole, while it was very susceptible to ciprofloxacin (MIC, 0.125 micrograms/ml) and rifampin (MIC, 0.5 micrograms/ml). PMID:2221869

  12. In vitro susceptibility of Ehrlichia sennetsu to antibiotics.

    PubMed

    Brouqui, P; Raoult, D

    1990-08-01

    Antibiotic efficacies were evaluated by Diff-Quik (Dade, Düdingen, Federal Republic of Germany) staining of Ehrlichia sennetsu in P388D1 murine macrophages grown in 96-well microtiter plates. Sennetsu disease is generally cured with tetracyclines. In vivo, E. sennetsu is susceptible to doxycycline and is resistant to erythromycin, penicillin, and chloramphenicol. Our study confirmed, in vitro, the efficacy of doxycycline, which had an MIC of 0.125 micrograms/ml. E. sennetsu was found to be resistant to erythromycin, chloramphenicol, penicillin, gentamicin, and co-trimoxazole, while it was very susceptible to ciprofloxacin (MIC, 0.125 micrograms/ml) and rifampin (MIC, 0.5 micrograms/ml).

  13. Global surveillance of antibiotic sensitivity of Vibrio cholerae*

    PubMed Central

    O'Grady, F.; Lewis, M. J.; Pearson, N. J.

    1976-01-01

    Strains of Vibrio cholerae—1156 from various parts of the world—were examined by standardized antibiotic sensitivity tests in one centre, to determine the global incidence of antibiotic resistance in this organism and to assess the extent to which differences in methods of sensitivity testing might be responsible for discrepancies in the reported incidence of resistant strains. Of the strains examined, 1127 were fully sensitive to ampicillin, chloramphenicol, tetracycline, furazolidone, and three different sulphonamides, 27 showed stable and reproducible resistance to one or more of these agents, and 2 proved to contain a minority of cells with unstable, presumably plasmid-borne, resistance to chloram-phenicol. Unstable resistance to antibiotics may be common in V. cholerae but rarely recognized, and may account for some of the discrepancies in the reported incidence of resistant strains. PMID:1088100

  14. [Effect of hydroacridine derivatives on the sensitivity of polyresistant strains of Staphylococcus aureus and Escherichia coli to antibiotics].

    PubMed

    Chelysheva, G M; Zaikina, N A; Maliuga, O A

    1978-09-01

    Sensitivity of 4 clinical strains of Staph. aureus and E. coli to 13 hydroacridine derivatives and their combinations with antibiotics, such as benzylpenicillin, ampicillin, semi-synthetic penicillins, streptomycin, chloramphenicol, tetracycline, chlortetracycline, monomycin, oleandomycin and erythromycin was studied. The highest bacteriostatic effect was observed on the use of perhydroactidine derivatives with benzylpenicillin or ampicillin with respect to polyresistant penicillinase-producing strains of Staph. aureus, resistance of which to these antibiotics was decreased 250--1000 times. Under the effect of the above compounds the staphylococcal resistance to chloramphenicol, tetracycline, chlortetracycline, oleandomycine and erythromycin decreased 2--66 times. The combinations of hydroacridine with the antibiotics, except 10-amino-trans-syn-trans-perhydroacridine had no effect on the resistance of the E. coli strains. The results of the combined effect of the above substances were associated with their chemical nature, the bacterial type and possibly the character of the strain resistance.

  15. [Hydrogen metabolism in Anabaena variabilis in the dark].

    PubMed

    Gogotov, I N; Kosiak, A V

    Cells and extracts of the cyanobacterium Anabaena variabilis are capable of hydrogen absorption in the dark in the presence of H-acceptors with various redox potentials. Preliminary adaptation of the cells to anaerobic conditions has no effect on the process. A. variabilis can also evolve hydrogen in the dark. Reduced methylviologen (RMV), formiate, pyruvate, and glucose may be substrates for hydrogen evolution by the cells. The extracts evolve hydrogen in the presence of RMV, benzylviologen, azocarmine, or NAD (P) H + ATP. No adaptation of the cells to anaerobic conditions is required for hydrogen evolution from RMV, and chloramphenicol has no effect on the process. The rate of hydrogen evolution is however higher in the cells adapted to anaerobic conditions. Production of hydrogen from pyruvate by the cells adapted and non-adapted to anaerobic conditions was detected only after their incubation with the substrate during 2--3 hours, and chloramphenicol inhibited the process.

  16. The mode of action of pleuromutilin derivatives. Location and properties of the pleuromutilin binding site on Escherichia coli ribosomes.

    PubMed

    Högenauer, G

    1975-03-03

    Using equilibrium dialysis techniques it could be demonstrated that (a) the pleuromutilin derivative 14-deoxy-14[(2-diethylaminoethyl)-mercaptoacetoxy] dihydromutilin HCl binds to one site per ribosome specifically, (b) the binding constant is 1.3 times 10(7) M(-1) and (c) chloramphenicol and puromycin compete with binding of the pleuromutilin derivative. Similarly the nucleotides CpA and CpCpA also displace the unsaturated derivative of the above-mentioned pleuromutilin compound. These findings suggest that the ribosomal binding site for pleuromutilin overlaps with that for chloramphenicol and analogs of the 3'-terminus of a tRNA, like puromycin or the nucleotides CpA and CpCpA.

  17. Antibiotic resistance of Campylobacter in raw retail chickens and imported chicken portions.

    PubMed Central

    Wilson, I. G.

    2003-01-01

    Campylobacter isolates from raw retail chickens (n = 434) sampled between 1998 and 2000 were tested for resistance to 12 antibiotics. Among 208 campylobacters tested, more than 90% of isolates were susceptible to 4 out of 9 antibiotics (nalidixic acid, erythromycin, chloramphenicol and gentamicin). Most campylobacters were resistant to 3 antibiotics and multiple resistance was found in 4%. Ciprofloxacin resistance was 11%. Campylobacter contamination (28%) in imported chickens (n = 150) was almost half that found in local whole chickens (50%), but the resistance of imported isolates (n = 42) was similar to that of local campylobacters. Resistance in isolates from imported chicken breasts was generally more common, but to only 4 antibiotics. Resistance patterns of chicken isolates were compared to human clinical isolates (n = 494), and a greater similarity was found between the clinical and local isolates than with imported campylobacters. Lower chloramphenicol resistance was found in clinical Campylobacter isolates than in those from chicken sources. PMID:14959786

  18. Minimal inhibitory concentrations of antimicrobial agents against Actinobacillus pleuropneumoniae.

    PubMed Central

    Nadeau, M; Larivière, S; Higgins, R; Martineau, G P

    1988-01-01

    Forty-five isolates of Actinobacillus pleuropneumoniae were tested for susceptibility to 12 antimicrobial agents using a microdilution method for the minimal inhibitory concentration determinations. These results confirmed the high prevalence of A. pleuropneumoniae strains resistant to antibiotics as reported earlier using the disc diffusion method (Kirby-Bauer method). While 36% of the isolates were resistant to the penicillins, 47% were resistant to chloramphenicol and 68% were resistant to tetracycline. Minimal inhibitory concentrations for the resistant isolates were approximately 32 times higher than those for the susceptible isolates to the above antibacterial agents. The isolates were in general weakly susceptible or resistant to spectinomycin, lincomycin, tiamulin and spiramycin whereas most of them were susceptible to gentamicin, trimethoprim and erythromycin. The susceptibility pattern was similar throughout the 1980 to 1984 period. The 14 serotype 5 isolates were more resistant to tetracycline but less resistant to chloramphenicol and the penicillins than the 28 serotype 1 isolates. PMID:3167716

  19. Synergistic antibacterial activity of Salvia officinalis and Cichorium intybus extracts and antibiotics.

    PubMed

    Stefanović, Olgica D; Stanojević, Dragana D; Comić, Ljiljana R

    2012-01-01

    Synergistic activity of Salvia officinalis and Cichorium intybus extracts and commonly used antibiotics, amoxicillin and chloramphenicol, were evaluated. Interactions between plant extracts and antibiotics were tested by checkerboard method and interpreted as FIC index. Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and clinical isolates Staphylococcus aureus, Bacillus subtilis, Enterobacter cloacae, Klebsiella pneumoniae, Escherichia coli and Proteus mirabilis were used. Salvia officinalis showed better synergistic capacity than Cichorium intybus. Synergistic interactions were observed between amoxicillin and acetone or ethyl acetate extract of Salvia officinalis and between chloramphenicol and ethyl acetate extract of Salvia officinalis. In the presence of sub-inhibitory concentration (1/4 MIC to 1/32 MIC) of sage extracts, the MIC values of antibiotics were decreased by 2- to 10-fold. Synergism was observed against all test bacteria, except Escherichia coli. The combinations of acetone and ethyl acetate extract from Cichorium intybus and antibiotics resulted in additive and indifferent effects against tested bacteria.

  20. Direct identification and recognition of yeast species from clinical material by using albicans ID and CHROMagar Candida plates.

    PubMed Central

    Baumgartner, C; Freydiere, A M; Gille, Y

    1996-01-01

    Two chromogenic media, Albicans ID and CHROMagar Candida agar plates, were compared with a reference medium, Sabouraud-chloramphenicol agar, and standard methods for the identification of yeast species. This study involved 951 clinical specimens. The detection rates for the two chromogenic media for polymicrobial specimens were 20% higher than that for the Sabouraud-chloramphenicol agar plates. The rates of identification of Candida albicans for Albicans ID and CHROMagar Candida agar plates were, respectively, 37.0 and 6.0% after 24 h of incubation and 93.6 and 92.2% after 72 h of incubation, with specificities of 99.8 and 100%. Furthermore, CHROMagar Candida plates identified 13 of 14 Candida tropicalis and 9 of 12 Candida krusei strains after 48 h of incubation. PMID:8789038

  1. The In Vitro Antimicrobial Effects of Lavandula angustifolia Essential Oil in Combination with Conventional Antimicrobial Agents.

    PubMed

    de Rapper, Stephanie; Viljoen, Alvaro; van Vuuren, Sandy

    2016-01-01

    The paper focuses on the in vitro antimicrobial activity of Lavandula angustifolia Mill. (lavender) essential oil in combination with four commercial antimicrobial agents. Stock solutions of chloramphenicol, ciprofloxacin, nystatin, and fusidic acid were tested in combination with L. angustifolia essential oil. The antimicrobial activities of the combinations were investigated against the Gram-positive bacterial strain Staphylococcus aureus (ATCC 6538) and Gram-negative Pseudomonas aeruginosa (ATCC 27858) and Candida albicans (ATCC 10231) was selected to represent the yeasts. The antimicrobial effect was performed using the minimum inhibitory concentration (MIC) microdilution assay. Isobolograms were constructed for varying ratios. The most prominent interaction was noted when L. angustifolia essential oil was combined with chloramphenicol and tested against the pathogen P. aeruginosa (ΣFIC of 0.29). Lavendula angustifolia essential oil was shown in most cases to interact synergistically with conventional antimicrobials when combined in ratios where higher volumes of L. angustifolia essential oil were incorporated into the combination.

  2. Antimicrobial susceptibility of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from various animals.

    PubMed

    Rubin, Joseph E; Ball, Katherine R; Chirino-Trejo, Manuel

    2011-02-01

    This study characterized the antimicrobial susceptibility of 221 Staphylococcus aureus isolated from various species, and 60 canine Staphylococcus pseudintermedius isolated from 1986 through 2000 at the Western College of Veterinary Medicine (WCVM). Resistance of S. aureus was most common to penicillin (31%) and tetracycline (14%); resistance of S. pseudintermedius to penicillin was present in 8% and to tetracycline in 34% of isolates. Resistance to trimethoprim/sulfamethoxazole was only seen among S. pseudintermedius, and there was no resistance to amoxicillin/clavulanate, ampicillin/sulbactam, cephalothin, amikacin, gentamicin, enrofloxacin, chloramphenicol, or rifampin among any isolate. Inducible clindamycin resistance was found in both S. aureus and S. pseudintermedius, highlighting the need for careful interpretation of culture and susceptibility test results. There were significant differences in the minimum inhibitory concentrations of penicillin, ciprofloxacin, enrofloxacin, clindamycin, erythromycin, chloramphenicol, and tetracycline between avian, bovine, equine, and porcine isolates.

  3. In vitro interactions of Peucedanum officinale essential oil with antibiotics.

    PubMed

    Miladinović, Dragoljub L; Ilić, Budimir S; Kocić, Branislava D; Miladinović, Ljiljana C; Marković, Marija S

    2015-01-01

    The chemical composition and antibacterial activity of Peucedanum officinale L. (Apiaceae) essential oil were examined, as well as the association between it and antibiotics: tetracycline, streptomycin and chloramphenicol. The interactions of the essential oil with antibiotics were evaluated using the microdilution checkerboard assay. Monoterpene hydrocarbons, with α-phellandrene as the dominant constituent, were the most abundant compound class of the essential oil of P. officinale. The researched essential oil exhibited slight antibacterial activity against the tested bacterial strains in vitro. On the contrary, essential oil of P. officinale possesses a great synergistic potential with chloramphenicol and tetracycline. Their combinations reduced the minimum effective dose of the antibiotic and, consequently, minimised its adverse side effects. In addition, investigated interactions are especially successful against Gram-negative bacteria, the pharmacological treatment of which is very difficult nowadays.

  4. Antibiotics and immunity: effects of antibiotics on mitogen responsiveness of lymphocytes and interleukin-2 production.

    PubMed

    Ibrahim, M S; Maged, Z A; Haron, A; Khalil, R Y; Attallah, A M

    1988-12-01

    The immunomodulating properties of antimicrobial drugs may have important implications in prescriptive practice. This is particularly so for patients whose immune system has been compromised. In this study, tetracycline, cephalothin, rifampicin, polymyxin B and nitrofurantoin reduced mitogen responsiveness of both B and T lymphocytes of mouse spleen cells and human peripheral blood lymphocytes in vitro in a dose-dependent fashion. Ampicillin, chloramphenicol, gentamicin, streptomycin and erythromycin had no effect. In the in vivo study none of the antibiotics affected mouse spleen cell transformation in response to mitogen. The addition of interleukin-2 (IL-2) did not prevent the effect of the antibiotics tested on human lymphocytes in vitro. Cephalothin, chloramphenicol and gentamicin decreased IL-2 production by mouse spleen cells in vitro.

  5. Antibiotics and immunity: effects of antibiotics on natural killer, antibody dependent cell-mediated cytotoxicity and antibody production.

    PubMed

    Ibrahim, M S; Maged, Z A; Haron, A; Khalil, R Y; Attallah, A M

    1987-12-01

    We studied the effects of antibiotics on natural killer (NK), antibody dependent cell-mediated cytotoxicity (ADCC) and immunoglobulin production. When human peripheral blood lymphocytes were incubated overnight with the antibiotic before the assay, nitrofurantoin significantly reduced NK but not ADCC activity. Nitrofurantoin also suppressed both spontaneous and interferon-enhanced NK activities in a dose-dependent fashion. Though it did not affect spontaneous ADCC activity, nitrofurantoin suppressed interferon enhancement of ADCC. Chloramphenicol significantly decreased the number of plaque forming cells in mice. In addition to chloramphenicol, tetracycline, rifampicin, cephalothin, polymyxin B and nitrofurantoin reduced mitogen-induced polycloned immunoglobulin synthesis. Results of this study may have clinical relevance, especially in treating immunocompromised patients.

  6. Liposomes containing drugs for treatment of vaginal infections.

    PubMed

    Pavelić, Z; Skalko-Basnet, N; Jalsenjak, I

    1999-08-01

    To develop a novel vaginal delivery system, able to effectively deliver entrapped drugs during an extended period of time at the site of action, liposomes made of phosphatidylcholine were prepared by two different methods, namely the polyol dilution method and the proliposome method. Liposomes containing three commonly applied drugs in the treatment of vaginal infections: clotrimazole, metronidazole and chloramphenicol were tested for in vitro stability (in buffers at pH 4.5 and 5.9 representing pre- and postmenopausal vaginal pH). In situ stability (in the presence of cow vaginal mucosa) showed that after 6 h incubation (at 37 degrees C), liposomes retained more than 40% of originally entrapped clotrimazole, 28% of entrapped metronidazole or 37% of entrapped chloramphenicol. In vitro and in situ stability studies confirmed the applicability of liposomes as a carrier system for vaginal delivery. Even after 24 h of incubation in the presence of vaginal mucosa liposomes retained sufficient amounts of entrapped drugs.

  7. A study in vitro of the sensitivity to antibiotics of Bacteroides fragilis.

    PubMed

    Ingham, H R; Selkon, J B; Codd, A A; Hale, J H

    1968-07-01

    During a two-year period of observation Bacteroides species were isolated from specimens of pus and vaginal swabs from 115 patients in this hospital. Thirty-five representative strains proved on examination to be Bacteroides fragilis. Minimal inhibitory and minimal bactericidal concentrations of six antibiotics for these strains were determined. All strains were resistant to streptomycin, neomycin, and polymyxin, slightly sensitive to penicillin and ampicillin, and fully sensitive to tetracycline, chloramphenicol, erythromycin, and lincomycin. The minimum bactericidal concentrations of chloramphenicol, erythromycin, and lincomycin were two to four times the minimal inhibitory concentrations. Tetracycline failed to exert any consistent bactericidal effect.The treatment of patients with infections caused by B. fragilis is discussed in the light of the findings in vitro.

  8. Construction of two selectable markers for integrative/conjugative plasmids in Flavobacterium columnare

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Zou, Hong; Wang, Liangfa; Huang, Bei; Li, Nan; Wang, Guitang; Nie, Pin

    2012-03-01

    Flavobacterium columnare, the etiological agent of columnaris disease, is one of the most important and widespread bacterial pathogens of freshwater fish. In this study, we constructed two artificial selectable markers (chloramphenicol and spectinomycin resistance) for gene transfer in F. columnare. These two new artificial selectable markers, which were created by placing the chloramphenicol or spectinomycin resistance gene under the control of the native acs regulatory region of F. columnare, were functional in both F. columnare and Escherichia coli. The integrative/conjugative plasmids constructed by using these markers were introduced into F. columnare G4 via electroporation or conjugation. The integrated plasmid DNA was confirmed by Southern blotting and PCR analysis. These two markers can be employed in future investigations into gene deletion and the pathogenicity of virulence factors in F. columnare.

  9. Advances on the chromatographic determination of amphenicols in food.

    PubMed

    Guidi, Letícia R; Tette, Patrícia A S; Fernandes, Christian; Silva, Luiza H M; Gloria, Maria Beatriz A

    2017-01-01

    Antibiotics are widely used in veterinary medicine to treat and prevent diseases and their residues can remain in food of animal origin causing adverse effects to human health. Amphenicols (chloramphenicol, thiamphenicol, and florfenicol) may be found in foodstuffs, although the use of chloramphenicol has been prohibited in many countries due to its high toxicity. Since these antibiotics are usually present at trace levels in food, sensitive and selective techniques are required to detect them. This paper reviews analytical methods used since 2002 for the quantitative analysis of amphenicols in food. Sample preparation and separation/detection techniques are described and compared. The advantages and disadvantages of these procedures are discussed. Furthermore, the worldwide legislation and occurrence of these antibiotics in food matrices as well as future trends are also presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. [Antibiotic resistance in strains of Salmonella typhimurium and S. enteritidis isolated from poultry in the Czech Republic 1991-1992].

    PubMed

    Cízek, A; Kovarík, K

    1994-01-01

    Antibiotic resistance has been monitored in 293 strains of S. typhimurium and 260 strains of S. enteritidis isolated from poultry in Czech Republic in the years 1991 and 1992. Ninety per cent of all salmonella isolations examined by disc diffusion method (Bauer et al., 1966) were sensitive to all 8 antimicrobials (chloramphenicol, neomycin, tetracycline, streptomycin, colistin, ampicillin, kanamycin, sulfisoxazol) used for testing. The strains of S. typhimurium were more resistant than S. enteritidis strains, as seen from the percentage of resistant strains, 17.4% and 1.2% respectively. Thirty-two (62.7%) out of 51 resistant strains were multiresistant. The percentage of resistance in S. typhimurium strains was as follows: sulfisoxazol (12.3%), streptomycin (11.3%), tetracycline (4.4%) and chloramphenicol (1.7%).

  11. Quinazoline derivatives are efficient chemosensitizers of antibiotic activity in Enterobacter aerogenes, Klebsiella pneumoniae and Pseudomonas aeruginosa resistant strains.

    PubMed

    Chevalier, Jacqueline; Mahamoud, Abdallah; Baitiche, Milad; Adam, Elissavet; Viveiros, Miguel; Smarandache, Adriana; Militaru, Andra; Pascu, Mihail L; Amaral, Leonard; Pagès, Jean-Marie

    2010-08-01

    Amongst the three series of quinazoline derivatives synthesised and studied in this work, some molecules increase the antibiotic susceptibility of Gram-negative bacteria presenting multidrug-resistant phenotypes. N-alkyl compounds induced an increase in the activity of chloramphenicol, nalidixic acid and sparfloxacin, which are substrates of the AcrAB-TolC and MexAB-OprM efflux pumps in clinical isolates. These molecules are able to increase the intracellular concentration of chloramphenicol in efflux pump-overproducing strains. Their activity depends on the antibiotic structure, suggesting that different sites may be involved for the recognition of substrates by a given efflux pump. Quinazoline molecules exhibiting a nitro functional group are more active, and structure-activity relationship studies may be undertaken to identify the pharmacophoric group involved in the AcrB and MexB affinity sites.

  12. (Electro)Sensing of Phenicol Antibiotics-A Review.

    PubMed

    Pilehvar, Sanaz; Gielkens, Kristoffer; Trashin, Stanislav A; Dardenne, Freddy; Blust, Ronny; De Wael, Karolien

    2016-10-25

    The presence of residues from frequent antibiotic use in animal feed can cause serious health risks by contaminating products meant for human consumption such as meat and milk. The present paper gives an overview of the electrochemical methods developed for the detection of phenicol antibiotic residues (chloramphenicol, thiamphenicol, and florfenicol) in different kinds of foodstuffs. Electrochemical sensors based on different biomolecules and nanomaterials are described. The detection limit of various developed methods with their advantages and disadvantages will be highlighted.

  13. High level multiple antibiotic resistance among fish surface associated bacterial populations in non-aquaculture freshwater environment.

    PubMed

    Ozaktas, Tugba; Taskin, Bilgin; Gozen, Ayse G

    2012-12-01

    Freshwater fish, Alburnus alburnus (bleak), were captured from Lake Mogan, situated in Ankara, during spring. The surface mucus of the fish was collected and associated bacteria were cultured and isolated. By sequencing PCR-amplified 16S RNA encoding genes, the isolates were identified as members of 12 different genera: Acinetobacter, Aeromonas, Bacillus, Brevundimonas, Gordonia, Kocuria, Microbacterium, Mycobacterium, Pseudomonas, Rhodococcus, and Staphylococcus, in addition to one strain that was unidentified. The mucus-dwelling bacterial isolates were tested for resistance against ampicillin, kanamycin, streptomycin and chloramphenicol. About 95% of the isolates were found to be resistant to ampicillin, 93% to chloramphenicol, and 88% to kanamycin and streptomycin. A Microbacterium oxydans and the unidentified environmental isolate were resistant to all four antibiotics tested at very high levels (>1600 μg/ml ampicillin and streptomycin; >1120 μg/ml kanamycin; >960 μg/ml chloramphenicol). Only a Kocuria sp. was sensitive to all four antibiotics at the lowest concentrations tested (3.10 μg/ml ampicillin and streptomycin; 2.15 μg/ml kanamycin; 1.85 μg/ml chloramphenicol). The rest of the isolates showed different resistance levels. Plasmid isolations were carried out to determine if the multiple antibiotic resistance could be attributed to the presence of plasmids. However, no plasmid was detected in any of the isolates. The resistance appeared to be mediated by chromosome-associated functions. This study indicated that multiple antibiotic resistance at moderate to high levels is common among the current phenotypes of the fish mucus-dwelling bacterial populations in this temperate, shallow lake which has not been subjected to any aquaculturing so far but under anthropogenic effect being in a recreational area.

  14. Identification of a TAAT-containing motif required for high level expression of the COL1A1 promoter in differentiated osteoblasts of transgenic mice

    NASA Technical Reports Server (NTRS)

    Dodig, M.; Kronenberg, M. S.; Bedalov, A.; Kream, B. E.; Gronowicz, G.; Clark, S. H.; Mack, K.; Liu, Y. H.; Maxon, R.; Pan, Z. Z.; hide

    1996-01-01

    Our previous studies have shown that the 49-base pair region of promoter DNA between -1719 and -1670 base pairs is necessary for transcription of the rat COL1A1 gene in transgenic mouse calvariae. In this study, we further define this element to the 13-base pair region between -1683 and -1670. This element contains a TAAT motif that binds homeodomain-containing proteins. Site-directed mutagenesis of this element in the context of a COL1A1-chloramphenicol acetyltransferase construct extending to -3518 base pairs decreased the ratio of reporter gene activity in calvariae to tendon from 3:1 to 1:1, suggesting a preferential effect on activity in calvariae. Moreover, chloramphenicol acetyltransferase-specific immunofluorescence microscopy of transgenic calvariae showed that the mutation preferentially reduced levels of chloramphenicol acetyltransferase protein in differentiated osteoblasts. Gel mobility shift assays demonstrate that differentiated osteoblasts contain a nuclear factor that binds to this site. This binding activity is not present in undifferentiated osteoblasts. We show that Msx2, a homeodomain protein, binds to this motif; however, Northern blot analysis revealed that Msx2 mRNA is present in undifferentiated bone cells but not in fully differentiated osteoblasts. In addition, cotransfection studies in ROS 17/2.8 osteosarcoma cells using an Msx2 expression vector showed that Msx2 inhibits a COL1A1 promoter-chloramphenicol acetyltransferase construct. Our results suggest that high COL1A1 expression in bone is mediated by a protein that is induced during osteoblast differentiation. This protein may contain a homeodomain; however, it is distinct from homeodomain proteins reported previously to be present in bone.

  15. Inactivation and reactivation of antibiotic-resistant bacteria by chlorination in secondary effluents of a municipal wastewater treatment plant.

    PubMed

    Huang, Jing-Jing; Hu, Hong-Ying; Tang, Fang; Li, Yi; Lu, Sun-Qin; Lu, Yun

    2011-04-01

    Reports state that chlorination of drinking water and wastewater affects the proportions of antibiotic-resistant bacteria by potentially assisting in microbial selection. Studies on the effect of chlorination on like species of antibiotic-resistant bacteria, however, have shown to be conflicting; furthermore, few studies have inspected the regrowth or reactivation of antibiotic-resistant bacteria after chlorination in wastewater. To understand the risks of chlorination resulting from potentially selecting for antibiotic-resistant bacteria, inactivation and reactivation rates of both total heterotrophic bacteria and antibiotic-resistant bacteria (including penicillin-, ampicillin-, tetracycline-, chloramphenicol-, and rifampicin-resistant bacteria) were examined after chlorinating secondary effluent samples from a municipal wastewater treatment plant in this study. Our experimental results indicated similar inactivation rates of both total heterotrophic bacteria and antibiotic-resistant bacteria. Microbial community composition, however, was affected by chlorination: treating samples with 10 mg Cl(2)/L for 10 min resulted in chloramphenicol-resistant bacteria accounting for nearly 100% of the microbial population in contrast to 78% before chlorination. This trend shows that chlorination contributes to selection of some antibiotic-resistant strains. Reactivation of antibiotic-resistant bacteria occurred at 2.0 mg Cl(2)/L for 10 min; specifically, chloramphenicol-, ampicillin-, and penicillin-resistant bacteria were the three prevalent groups present, and the reactivation of chloramphenicol-resistant bacteria exceeded 50%. Regrowth and reactivation of antibiotic-resistant bacteria in secondary effluents after chlorination with a long retention time could threaten public health security during wastewater reuse. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Mitochondrial inheritance and disease.

    PubMed

    Fine, P E

    1978-09-23

    Spontaneously occurring variants of the D.N.A. content of mitochondria may be responsible for human disease. Among the prime candidates for such a mitochondrial aetiology are certain drug-induced blood dyscrasias, particularly that due to chloramphenicol. Because mitochondria are generally inherited from the female parent, such disorders should be clustered among matroclinally related individuals. The clinical manifestations of such diseases are a function of the manner in which mitochondria are allocated to somatic cells and tissues during development.

  17. [Transport of phenylalanine and tyrosine in Brevibacterium linens: specificity and incorporation into proteins].

    PubMed

    Boyaval, P; Moreira, E; Desmazeaud, M J

    1984-04-01

    The specificity of phenylalanine and tyrosine carriers was investigated using actively metabolizing cells of Brevibacterium linens. The cellular protein synthesis of resting cells was very weakly inhibited, even with high concentrations of chloramphenicol or tetracycline. The nonaromatic amino acids were weak inhibitors for these carriers, while fluorinate analogues of phenylalanine and tyrosine were very potent competitive inhibitors. In practice these analogues cannot be used to replace amino acids to evaluate transport without incorporation because they are incorporated in cellular proteins.

  18. Antibiotic sensitivities of enterococci isolated from treated root canals.

    PubMed

    Heintz, C E; Deblinger, R; Oliet, S

    1975-11-01

    Enterococci that persisted in debrided, medicated root canals were tested by the Kirby-Bauer procedure for sensitivity to various antibiotics. The 50 strains tested were uniformly sensitive to ampicillin and vancomycin. More than 90% were also sensitive to erythromycin. Varying degrees of sensitivity and resistance were noted to bacitracin, cephaloridine, cephalothin, chloramphenicol, gentamicin, and tetracycline. All organisms were either partly or wholly resistant to clindamycin; penicillin; streptomycin; and sulfadiazine, sulfamerazine, and sulfamethazine (triple sulfas).

  19. Demodicosis Treatment with Systemic Ivermectin.

    PubMed

    da Rocha, Manuel Coelho; Travassos, Ana Rita; Uva, Luís; Sequeira, Hortênsia; Filipe, Paulo

    2017-01-01

    A 23-year-old white man presented to our dermatology department complaining of pruriginous and erythematous papulopustules on the right cheek that had developed 6 months previously. He had a history of chronic blepharitis, complicated by a recurrent hordeolum that had been treated with warm compresses and topical antibiotic ointment (chloramphenicol) for approximately 2 years. The patient had oily skin and atopy (allergic rhinitis) and did not experience photosensitivity or flushing or have previous exposure to immunosuppressants or topical/systemic corticosteroids.

  20. The Biochemistry and Physiology of Bacterial Adhesion to Surfaces

    DTIC Science & Technology

    1984-01-20

    proteins may be similar to the "adhesins" employed by enterotoxigenic E. coli strains to adhere to intestinal epithelium (Vosbeck et al., 1979; 1982...chloramphenicol, tetracycline) reduced the adhesiveness of several E. coli strains to intestine monolayer cells. The DNA synthesis inhibitor nalidxic acid made... strains are not encapsulated, since glycocalyces and capsules make bacteria hydrophilic (Hogt et al. 1982). The nature of the hydrophobic moiety at the

  1. Wound infection by multiresistant Staphylococcus sciuri identified by molecular methods.

    PubMed

    Coimbra, Daniel G; Almeida, Alda G C S; Jùnior, Jorge B O; da Silva, Luiz A F; Pimentel, Beatriz J; Gitaì, Daniel L G; Moreira, Luciana S; Silva-Filho, Eurìpedes A; de Andrade, Tiago G

    2011-10-01

    We describe a case of wound infection by multidrug-resistant Staphylococcus sciuri in a patient admitted to hospital for injuries in Agreste Alagoas, Brazil, identified through broad-spectrum PCR and sequencing of 16S rDNA gene. Due to its high resistance profile, the infection was characterized as methicillin-resistant Staphylococcus presenting sensitive only to vancomycin and chloramphenicol. The injury resulting from trauma associated with infection resulted in amputation of the infected limb.

  2. Nodular panniculitis in a female toy poodle.

    PubMed

    Post, K

    1983-05-01

    A four month old female toy Poodle showing multiple nodules 2 to 3 cm in diameter, some of which had ruptured over the neck and trunk area, was diagnosed as having nodular panniculitis. The animal had been treated with a course of chloramphenicol and ampicillin for one month with no response. The diagnosis was based on history, clinical signs, laboratory data and dramatic response to the addition of corticosteroid to the antibiotic therapy.

  3. The Viral and Eukaryotic Distribution of the Internal Ribosome Entry Site (IRES) and its Potential as an Anti-Viral Translation Target

    DTIC Science & Technology

    1998-12-16

    binding protein bovine viral diarrhea virus chloramphenicol acetyl transferase human proto·oncogene classical swine fever virus coxs.ackievirus BI...C virus (HCV) and the pestiviruses. which include bovine viral diarrhea (BVDV), hog cholera virus (HChV). and classical swine fever virus (CSFV...hepatitis C virus and classical swine fever virus RNAs. J. Virol. 72:4775-4782. 109. Sonenberg. N. 1990. Poliovirus translation. Curro Top

  4. Draft Genome Sequence of the First NDM-1-Producing Providencia stuartii Strain Isolated in Portugal.

    PubMed

    Manageiro, Vera; Sampaio, Daniel A; Pereira, Patrícia; Rodrigues, Paulo; Vieira, Luís; Palos, Carlos; Caniça, Manuela

    2015-09-24

    We report here the draft genome sequence of the first NDM-1-producing Providencia stuartii strain isolated in Portugal. Sequence analyses revealed the presence of an incompatibility group A/C2 (IncA/C2) plasmid and of diverse acquired genes conferring resistance to β-lactams, aminoglycosides, tetracycline, macrolides, chloramphenicol, and sulfonamides. This sequence contributes to the evaluation of the spread of NDM-1 producers. Copyright © 2015 Manageiro et al.

  5. Draft Genome Sequence of the First NDM-1-Producing Providencia stuartii Strain Isolated in Portugal

    PubMed Central

    Sampaio, Daniel A.; Pereira, Patrícia; Rodrigues, Paulo; Vieira, Luís; Palos, Carlos

    2015-01-01

    We report here the draft genome sequence of the first NDM-1-producing Providencia stuartii strain isolated in Portugal. Sequence analyses revealed the presence of an incompatibility group A/C2 (IncA/C2) plasmid and of diverse acquired genes conferring resistance to β-lactams, aminoglycosides, tetracycline, macrolides, chloramphenicol, and sulfonamides. This sequence contributes to the evaluation of the spread of NDM-1 producers. PMID:26404603

  6. Doctor T. E. Woodward's legacy: from typhus to typhoid fever.

    PubMed

    Hornick, Richard B; Woodward, William E; Greisman, Sheldon E

    2007-07-15

    Dr. Theodore E. Woodward was one of the early giants of infectious diseases research who set the groundwork for the field. He was the first to evaluate vaccines against typhus, employing volunteers to test the effectiveness of the vaccines. This led to the evaluation of chloramphenicol for the treatment of rickettsial diseases and typhoid fever. Subsequently, he was influential in establishing a unique volunteer unit in Maryland in which a wide range of vaccines were evaluated.

  7. Mycotic keratitis due to Engyodontium album: first case report from India.

    PubMed

    Thamke, D C; Mendiratta, D K; Dhabarde, A; Shukla, A K

    2015-01-01

    Engyodontium album is a rare and an unusual human pathogen. It is a common inhabitant of waste and moist material and frequently isolated from substrates such as paper, jute, linen and painted walls. This fungus grew within 3 days on SDA with chloramphenicol from corneal scrapping of a 70-year-old male farmer with a history of trauma by unknown vegetative matter. The fungus can be confused with Tritirachium sp and Beauveria sp.

  8. Identification of a TAAT-containing motif required for high level expression of the COL1A1 promoter in differentiated osteoblasts of transgenic mice

    NASA Technical Reports Server (NTRS)

    Dodig, M.; Kronenberg, M. S.; Bedalov, A.; Kream, B. E.; Gronowicz, G.; Clark, S. H.; Mack, K.; Liu, Y. H.; Maxon, R.; Pan, Z. Z.; Upholt, W. B.; Rowe, D. W.; Lichtler, A. C.

    1996-01-01

    Our previous studies have shown that the 49-base pair region of promoter DNA between -1719 and -1670 base pairs is necessary for transcription of the rat COL1A1 gene in transgenic mouse calvariae. In this study, we further define this element to the 13-base pair region between -1683 and -1670. This element contains a TAAT motif that binds homeodomain-containing proteins. Site-directed mutagenesis of this element in the context of a COL1A1-chloramphenicol acetyltransferase construct extending to -3518 base pairs decreased the ratio of reporter gene activity in calvariae to tendon from 3:1 to 1:1, suggesting a preferential effect on activity in calvariae. Moreover, chloramphenicol acetyltransferase-specific immunofluorescence microscopy of transgenic calvariae showed that the mutation preferentially reduced levels of chloramphenicol acetyltransferase protein in differentiated osteoblasts. Gel mobility shift assays demonstrate that differentiated osteoblasts contain a nuclear factor that binds to this site. This binding activity is not present in undifferentiated osteoblasts. We show that Msx2, a homeodomain protein, binds to this motif; however, Northern blot analysis revealed that Msx2 mRNA is present in undifferentiated bone cells but not in fully differentiated osteoblasts. In addition, cotransfection studies in ROS 17/2.8 osteosarcoma cells using an Msx2 expression vector showed that Msx2 inhibits a COL1A1 promoter-chloramphenicol acetyltransferase construct. Our results suggest that high COL1A1 expression in bone is mediated by a protein that is induced during osteoblast differentiation. This protein may contain a homeodomain; however, it is distinct from homeodomain proteins reported previously to be present in bone.

  9. Possible Application of Biotechnology to the Development of Biological Agents by Potential Enemies

    DTIC Science & Technology

    1987-06-01

    for -28- t-: & penicillinase (bcta-lactamasc). Other plasmids carry resistance to heavy metals , erythromycin, chloramphenicol, tetracyclines...to conduct BW research for defensive purposes only and to limit studies to those that would protect the soldier from the effects of BW agents...resulting effect on the infected troops reduced the tactical value. Also, the impossibility of controlling the spread of the organisms following

  10. Coagulase-negative Staphylococcus sp septicemia in a lovebird.

    PubMed

    Bounous, D I; Schaeffer, D O; Roy, A

    1989-10-15

    Gram-positive cocci were observed within phagocytes in the blood of a psittacine with clinical signs of blindness and CNS disease. A coagulase-negative Staphylococcus sp was isolated from blood cultures, and the bird was successfully treated with chloramphenicol. Although the primary route of infection was not determined, the infection spread secondarily via the hematogenous route and localized intraocularly. Usually, only coagulase-positive strains of Staphylococcus are considered pathogenic, and are seldom diagnosed before death.

  11. Antibiotics induce mitonuclear protein imbalance but fail to inhibit respiration and nutrient activation in pancreatic β-cells.

    PubMed

    Santo-Domingo, Jaime; Chareyron, Isabelle; Broenimann, Charlotte; Lassueur, Steve; Wiederkehr, Andreas

    2017-08-15

    Chloramphenicol and several other antibiotics targeting bacterial ribosomes inhibit mitochondrial protein translation. Inhibition of mitochondrial protein synthesis leads to mitonuclear protein imbalance and reduced respiratory rates as confirmed here in HeLa and PC12 cells. Unexpectedly, respiration in INS-1E insulinoma cells and primary human islets was unaltered in the presence of chloramphenicol. Resting respiratory rates and glucose stimulated acceleration of respiration were also not lowered when a range of antibiotics including, thiamphenicol, streptomycin, gentamycin and doxycycline known to interfere with bacterial protein synthesis were tested. However, chloramphenicol efficiently reduced mitochondrial protein synthesis in INS-1E cells, lowering expression of the mtDNA encoded COX1 subunit of the respiratory chain but not the nuclear encoded ATP-synthase subunit ATP5A. Despite a marked reduction of the essential respiratory chain subunit COX1, normal respiratory rates were maintained in INS-1E cells. ATP-synthase dependent respiration was even elevated in chloramphenicol treated INS-1E cells. Consistent with these findings, glucose-dependent calcium signaling reflecting metabolism-secretion coupling in beta-cells, was augmented. We conclude that antibiotics targeting mitochondria are able to cause mitonuclear protein imbalance in insulin secreting cells. We hypothesize that in contrast to other cell types, compensatory mechanisms are sufficiently strong to maintain normal respiratory rates and surprisingly even result in augmented ATP-synthase dependent respiration and calcium signaling following glucose stimulation. The result suggests that in insulin secreting cells only lowering COX1 below a threshold level may result in a measurable impairment of respiration. When focusing on mitochondrial function, care should be taken when including antibiotics targeting translation for long-term cell culture as depending on the sensitivity of the cell type analyzed

  12. Effect of cooking and cold storage on biologically active antibiotic residues in meat.

    PubMed Central

    O'Brien, J. J.; Campbell, N.; Conaghan, T.

    1981-01-01

    An investigation was undertaken to see if cooking or cold storage would destroy or decrease the level of biologically active antibiotic in tissues from animals given therapeutic doses of antibiotic on three occasions prior to slaughter. The effects of cooking and cold storage on the biological activity of the residues of ampicillin, chloramphenicol, oxytetracycline, streptomycin and sulphadimidine were varied; in some instances the effects were minimal, in others nil. PMID:7310129

  13. A Literature Review - Problem Definition Studies on Selected Toxic Chemicals. Volume 6. Occupational Health and Safety and Environmental Aspects of Urea-Formaldehyde Resins

    DTIC Science & Technology

    1978-04-01

    such as penicillin, streptomycin, chloramphenicol, tetracycline, erythromycin, neomycin, polymyxin, chlor- tetracycline, oxytetracycline , novobi’ocin...so=-e nitrogen in the polymers was converted to nitrogen gas (N2 ) by the flaming coabustion. The stability of urea-form.aldehyde resins against...armonia (12). The stability of urea-formaldehyde resins against ultraviolet irradiation was studied by applying a film of the resin on the i•r plate

  14. Risk of Relapse Associated with Doxycycline Therapy for Scrub Typhus

    DTIC Science & Technology

    1981-01-01

    143150-9 202 Rickettsiae ard Rickettsial Diseases I. INTRODUCTION Chloramphenicol (Chloromycetin) or oxytetracycline (Terra- mycin) are the drugs...doses of oxytetracycline in a double blind, randomized trial conducted in a population of scrub typhus patients who were exposed in the Pescadores... oxytetracycline , 500 mg every 6 hrs for 7 days (OXY, 23 patients). Drug and placebo were manufactured in such a way and administered every 6 hrs for 7

  15. The Influence of Primary and Secondary DNA Structure in Deletion and Duplication between Direct Repeats in Escherichia Coli

    PubMed Central

    Trinh, T. Q.; Sinden, R. R.

    1993-01-01

    We describe a system to measure the frequency of both deletions and duplications between direct repeats. Short 17- and 18-bp palindromic and nonpalindromic DNA sequences were cloned into the EcoRI site within the chloramphenicol acetyltransferase gene of plasmids pBR325 and pJT7. This creates an insert between direct repeated EcoRI sites and results in a chloramphenicol-sensitive phenotype. Selection for chloramphenicol resistance was utilized to select chloramphenicol resistant revertants that included those with precise deletion of the insert from plasmid pBR325 and duplication of the insert in plasmid pJT7. The frequency of deletion or duplication varied more than 500-fold depending on the sequence of the short sequence inserted into the EcoRI site. For the nonpalindromic inserts, multiple internal direct repeats and the length of the direct repeats appear to influence the frequency of deletion. Certain palindromic DNA sequences with the potential to form DNA hairpin structures that might stabilize the misalignment of direct repeats had a high frequency of deletion. Other DNA sequences with the potential to form structures that might destabilize misalignment of direct repeats had a very low frequency of deletion. Duplication mutations occurred at the highest frequency when the DNA between the direct repeats contained no direct or inverted repeats. The presence of inverted repeats dramatically reduced the frequency of duplications. The results support the slippage-misalignment model, suggesting that misalignment occurring during DNA replication leads to deletion and duplication mutations. The results also support the idea that the formation of DNA secondary structures during DNA replication can facilitate and direct specific mutagenic events. PMID:8325478

  16. Tsutsugamushi disease presenting with aortic valve endocarditis: a case report and literature review

    PubMed Central

    Yu, Shujie; Yu, Xianguan; Zhou, Bin; Liu, Dinghui; Wang, Min; Zhang, Hui; Qian, Xiaoxian

    2016-01-01

    Tsutsugamushi disease is a zoonotic disease caused by Orientia tsutsugamushi in which humans are accidental hosts. Infective endocarditis associated with Tsutsugamushi disease has not been previously reported. We are describing a case of Tsutsugamushi disease presenting with aortic valve endocarditis. The clinical data of a 67-year-old female with O. tsutsugamushi-induced aortic valve endocarditis was summarized retrospectively and analyzed with a literature review. Treatment of O. tsutsugamushi-induced aortic valve endocarditis with chloramphenicol is recommended. PMID:28078179

  17. Multiple Clones within Multidrug-Resistant Salmonella enterica Serotype Typhimurium Phage Type DT104

    PubMed Central

    Markogiannakis, Antonis; Tassios, Panayotis T.; Lambiri, Maria; Ward, Linda R.; Kourea-Kremastinou, Jenny; Legakis, Nicholas J.; Vatopoulos, Alkiviadis C.

    2000-01-01

    Six distinct clones were present among Greek multidrug-resistant Salmonella enterica serotype Typhimurium phage type DT104, since isolates belonging to resistance phenotypes including the ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) core could be distinguished with respect to their pulsed-field gel electrophoresis patterns, int1 integron structures, and presence or absence of antibiotic resistance genes ant(3")-Ia, pse-1, and tem-1. PMID:10699039

  18. First description of an RND-type multidrug efflux pump in Achromobacter xylosoxidans, AxyABM.

    PubMed

    Bador, Julien; Amoureux, Lucie; Duez, Jean-Marie; Drabowicz, Anthony; Siebor, Eliane; Llanes, Catherine; Neuwirth, Catherine

    2011-10-01

    Achromobacter xylosoxidans is an emerging pathogen in cystic fibrosis patients. The multidrug resistance of these bacteria remains poorly understood. We have characterized in a clinical strain the first resistance-nodulation-cell division (RND)-type multidrug efflux pump in this species: AxyABM. The inactivation of the transporter component axyB gene led to decreased MICs of cephalosporins (except cefepime), aztreonam, nalidixic acid, fluoroquinolones, and chloramphenicol.

  19. First Description of an RND-Type Multidrug Efflux Pump in Achromobacter xylosoxidans, AxyABM▿

    PubMed Central

    Bador, Julien; Amoureux, Lucie; Duez, Jean-Marie; Drabowicz, Anthony; Siebor, Eliane; Llanes, Catherine; Neuwirth, Catherine

    2011-01-01

    Achromobacter xylosoxidans is an emerging pathogen in cystic fibrosis patients. The multidrug resistance of these bacteria remains poorly understood. We have characterized in a clinical strain the first resistance-nodulation-cell division (RND)-type multidrug efflux pump in this species: AxyABM. The inactivation of the transporter component axyB gene led to decreased MICs of cephalosporins (except cefepime), aztreonam, nalidixic acid, fluoroquinolones, and chloramphenicol. PMID:21807978

  20. Melibiose is hydrolyzed exocellularly by an inducible exo-alpha-galactosidase in Azotobacter vinelandii.

    PubMed

    Wong, T Y

    1990-07-01

    Azotobacter vinelandii hydrolyzed melibiose exocellularly, leading to an accumulation of free glucose and galactose in the medium. This enzyme could also be induced by galactose, raffinose, and stachyose. The alpha-galactosidase activity could be detected quantitatively by using p-nitrophenyl-alpha-galactopyranoside as a substrate for intact cells. Chloramphenicol totally inhibited the induction of this enzyme. However, benzyl alcohol inhibited the secretion of this enzyme but did not inhibit the biosynthesis of the enzyme.

  1. Toward an Inexpensive Test for Vitamin D Levels in Blood

    DTIC Science & Technology

    2013-10-01

    respectively. The cells containing both CYP-pET20b and pGro7 were inoculated in 5 mL TB broth containing 100 µg/mL ampicillin and 35 µg/mL chloramphenicol...and incubated overnight at 37 C with shaking. The overnight culture was diluted into 2 x 1 L TB broth containing 100 µg/mL ampicillin and 35 µg/mL

  2. Scrub typhus in Korea: importance of early clinical diagnosis in this newly recognized endemic area.

    PubMed

    Yi, K S; Chong, Y; Covington, S C; Donahue, B J; Rothen, R L; Rodriguez, J; Arthur, J D

    1993-04-01

    Scrub typhus became a well recognized infectious disease threat to military operations in the Pacific Theater during World War II. Early diagnosis and treatment with tetracycline or chloramphenicol dramatically reduces the mortality and morbidity of this disease. Korea is a newly recognized scrub typhus endemic country. We report our experience with 189 scrub typhus patients seen at a civilian outpatient clinic in Chinhae, Republic of Korea, from 1985 through 1990, and verify the accuracy of clinical diagnosis by serologic tests.

  3. Regulation of nitrate reductase at the transcriptional and translational levels in Escherichia coli.

    PubMed

    Ruiz-Herrera, J; Salas-Vargas, I

    1976-04-02

    Nitrate reductase from Escherichia coli is induced by nitrate and derepressed by oxygen removal after a lag phase. Elimination of inducer, shift to aerobic conditions and addition of actinomycin D causes the decline in the rate of its synthesis, which eventually may stop. Kinetic analysis of the sensitivity of the biosynthetic process to oxygen, chloramphenicol, actinomycin D and rifampicin gave results which we interprete as evidence that oxygen (and possibly nitrate) affect simultaneously both the transcriptional and translational processes.

  4. Role of OmpA in the Multidrug Resistance Phenotype of Acinetobacter baumannii

    PubMed Central

    Fàbrega, Anna; Roca, Ignasi; Sánchez-Encinales, Viviana; Vila, Jordi; Pachón, Jerónimo

    2014-01-01

    Acinetobacter baumannii has emerged as a nosocomial pathogen with an increased prevalence of multidrug-resistant strains. The role of the outer membrane protein A (OmpA) in antimicrobial resistance remains poorly understood. In this report, disruption of the ompA gene led to decreased MICs of chloramphenicol, aztreonam, and nalidixic acid. We have characterized, for the first time, the contribution of OmpA in the antimicrobial resistance phenotype of A. baumannii. PMID:24379205

  5. ANTIBACTERIAL ACTIVITY OF ROOT EXTRACT OF TRIANTHEMA DECANDRA

    PubMed Central

    Jaswanth, A.; Jagannathan, K.; Heisonrobert, S. Jerry; Loganathan, V.; Manimaran, S.; Ruckmani, K.

    2002-01-01

    Methanolic extract of Trianthema decandra was investigated for its antibacterial activity against staphylococcus aureus (NCIM 2079), Escherichia coli (NCIM 2065), Bacillus subtilis (NCIM 2063), Pseudomonas aeruginosa (NICIM 2036) and Proteus vulgaris (NICIM 2027) at 100 μg/disc using disc diffusion method. The extract showed significant antibacterial activity and were comparable to Chloramphenicol (30/ μg/disc). Our findings confirm the traditional therapeutic claims for this herb. PMID:22557045

  6. The Armed Forces Epidemiological Board: Its First Fifty Years, 1940-1990

    DTIC Science & Technology

    1990-02-01

    sufficient evidence to establish the cause of th:s peculiar disease, it became apparent to the research team that urothelial cancers of the renal pelvis...Forces Epidenh:ogicai Board - Reported the first therapeutic efficacy of chloramphenicol and tetracycline in bubonic, septicemic, and pulmonic plague...a fibroma or a papilloma. The adses carry his name, and have had very important implications in understanding the pathogeniesis oif cancer . Dick had a

  7. Outcome in three groups of patients with typhoid fever in Indonesia between 1948 and 1990.

    PubMed

    van den Bergh, E T; Gasem, M H; Keuter, M; Dolmans, M V

    1999-03-01

    The outcome in three groups of patients with bacteriologically confirmed typhoid fever caused by Salmonella typhi, treated during three episodes between 1948 and 1990 in Java, Indonesia, was compared by retrospective analysis of hospital records. The study population consisted of three groups of patients. Group I (n = 50) was treated in Batavia (the present Jakarta) from 1948 to 1950, Group II (n = 61) in Yogyakarta from 1952 to 1956, Group III (n = 105) in Semarang from 1989 to 1990. Main outcome measures were days until defervescence, early relapses during hospitalization, duration of hospital stay, complications and mortality. Group I received supportive treatment only, Group II low doses of chloramphenicol (total 12.5 g) and Group III full doses of chloramphenicol (total 27 g); occasionally other antibiotics were used. In Group I, II and III the mean number of days until defervescence was 16, 8 and 6 and the mean number of days in hospital 43, 47 and 15, respectively. Mortality was 26%, 10% and 5% and complications occurred in 38%, 18% and 13%, respectively. Between Group I and Group II the differences in mortality and complications were statistically significant (P < 0.05). Compared to Group I the proportion of early relapses was higher in Group II, but was zero in Group III. There were significantly fewer gastrointestinal complications in Group II than in Group I (P < 0.01) and even fewer in Group III. When no antibiotic against S. typhi was available, typhoid fever had a protracted course, and only 74% of patients survived. Even with low dosages of chloramphenicol, defervescence was earlier and mortality and complications decreased dramatically, but early relapses were frequent. Full doses of chloramphenicol for a sufficient period of time only slightly reduced mortality and complications further, but eliminated early relapses completely.

  8. Salmonella enterica Typhimurium fljBA operon stability: implications regarding the origin of Salmonella enterica I 4,[5],12:i:.

    PubMed

    Tomiyama, M P O; Werle, C H; Milanez, G P; Nóbrega, D B; Pereira, J P; Calarga, A P; Flores, F; Brocchi, M

    2015-12-29

    Salmonella enterica subsp enterica serovar 4,5,12:i:- has been responsible for many recent Salmonella outbreaks worldwide. Several studies indicate that this serovar originated from S. enterica subsp enterica serovar Typhimurium, by the loss of the flagellar phase II gene (fljB) and adjacent sequences. However, at least two different clones of S. enterica 4,5,12:i:- exist that differs in the molecular events responsible for fljB deletion. The aim of this study was to test the stability of the fljBA operon responsible for the flagellar phase variation under different growth conditions in order to verify if its deletion is a frequent event that could explain the origin and dissemination of this serovar. In fact, coding sequences for transposons are present near this operon and in some strains, such as S. enterica Typhimurium LT2, the Fels-2 prophage gene is inserted near this operon. The presence of mobile DNA could confer instability to this region. In order to examine this, the cat (chloramphenicol acetyltransferase) gene was inserted adjacent to the fljBA operon so that deletions involving this genomic region could be identified. After growing S. enterica chloramphenicol-resistant strains under different conditions, more than 104 colonies were tested for the loss of chloramphenicol resistance. However, none of the colonies were sensitive to chloramphenicol. These data suggest that the origin of S. enterica serovar 4,5,12:i:- from Typhimurium by fljBA deletion is not a frequent event. The origin and dissemination of 4,5,12:i:- raise several questions about the role of flagellar phase variation in virulence.

  9. Effects of antibiotics on UV-stimulated tube growth of Pinus silvestris pollen.

    PubMed

    Zelles, L

    1977-12-12

    Studies were made to investigate the effects of different antibiotics on unirradiated pollen and on pollen with enhanced tube growth, stimulated by low doses of UV-light. The antibiotics mitomycin, chloramphenicol, tetracyclin, penicillin, nystatin and carbony-cyanid phenylhydrazon were not able to suppress tube growth stimulation of pine pollen. The data obtained are discussed in view of the stimulation mechanism of low doses of UVP-light.

  10. In Vivo Transcription Studies of Coliphage 186

    PubMed Central

    Finnegan, Jean; Egan, J. Barry

    1981-01-01

    The temporal apperance of transcripts from the 186 chromosome has been determined by pulse-labeling at different times after prophage induction and hybridization of RNA extracts to cloned restriction fragments of 186. Studies with different mutants and induction in the presence of chloramphenicol suggested a controlled pattern of transcription and led us to propose the existence of a primary control gene analogous to the λ gene N. PMID:6165842

  11. Salmonellosis in Indonesia: Phage-Type of Salmonella oranienburg Obtained from Hospitalized Patients in Jakarta, Indonesia

    DTIC Science & Technology

    1980-09-15

    difference of two proportions) and greater overall reistance (all antibiotics combined P = 0.-001, even when tetracycline isI excluded; P = 0-022 ((’hi...susceptible to dehydration. Phage type I was sig- nificantly more resistant than phage type II to the individual antibiotics : tetra- cycline, chloramphenicol...kanamycin and neomycin. However, there was no difference in their respective antibiotic resistance patterns as measured by disk and MIC assay. All

  12. Synthesis of novel quinoxalinone derivatives by conventional and microwave methods and assessing their biological activity.

    PubMed

    Nasir, Waqar; Munawar, Munawar Ali; Ahmed, Ejaz; Sharif, Ahsan; Ahmed, Saeed; Ayub, Amjad; Khan, Misbahul Ain; Nasim, Faizul Hassan

    2011-10-01

    In this study, twenty-one arylaminoquinoxalinone derivatives were synthesized and their antibacterial activities against Staphylococci aureus, Pseudomonas aureus, Escherichia coli, Bacillus subtilis, Salmonella typhi, and Shigella pneumoniae were evaluated relative to known antibiotics; augmentin, ampicillin, and chloramphenicol. The insecticidal activities of the prepared compounds were also investigated against Tribolium castaneum using permethrin as a standard insecticide. The derivatives were synthesized using both conventional and microwave techniques. Their structures were confirmed using spectral techniques and elemental analysis.

  13. Relative impact of clinical evidence and over-the-counter prescribing on topical antibiotic use for acute infective conjunctivitis.

    PubMed

    Davis, Helen; Mant, David; Scott, Caroline; Lasserson, Daniel; Rose, Peter W

    2009-12-01

    Acute infective conjunctivitis is a common presentation in general practice. In 2005, three placebo-controlled clinical trials showed that use of topical antibiotics had a small effect on time to clinical resolution. In the same year, chloramphenicol eye drops were made available for sale over the counter. To compare the relative impact of clinical trial evidence and a change to over-the-counter availability on community use of topical chloramphenicol. Observational study using mainly routinely collected data for England. National prescribing data for England and local data from general practices in Oxfordshire, England. Data were collated from three sources: GP prescriptions from the Prescription Pricing Authority, wholesale supply to pharmacists from IMS Health, and an audit of delayed prescribing and non-prescribing from electronic consultation records for acute conjunctivitis, in four general practices. The number of general practice prescriptions for topical chloramphenicol fell from 2.3 million in 2004 to 1.9 million in 2007, a reduction of 15.5%. In contrast, over-the-counter sales by pharmacists have increased steadily. The net effect of these changes has been a 47.8% increase in total chloramphenicol use during 2005-2007, with 1.1 million additional packs being used in 2007 compared to 2004. Making an antibiotic available over the counter increases its use substantially. This is in conflict with the important public health message that antibiotic use needs to be reduced to combat resistance. These findings support the views of the Chief Medical Officer that no more antibiotics should currently be made available over the counter.

  14. Determination of asymptomatic carrier rate of beta-haemolytic group B Streptococcus in vaginas of pregnant women in Ibadan, Nigeria.

    PubMed

    Olanisebe, S B; Adetosoye, A I

    1986-04-01

    Bacteriological studies of 500 vaginal swabs from pregnant women in second and third trimester from 4 government hospitals in Ibadan showed that 8 (1.6 per cent) were found to be culture-positive for Group B Streptococcus. Five (1.0 per cent) were found to harbour group D streptococci. All the 8 group B Streptococcus isolates were sensitive to erythromycin, methicillin, penicillin G, ampicillin and chloramphenicol in decreasing order. They were resistant to tetracycline, sulphafurazole and streptomycin.

  15. [Distribution and changes of antibiotic susceptibility of genus Haemophilus (author's transl)].

    PubMed

    Kosakai, N; Oguri, T

    1976-02-01

    We studied on the distribution and changes of antibiotic susceptibility of H. influenzae, H. parainfluenzae and H. parahaemolyticus isolated from clinical materials, mainly from sputum and pharyngeal swabs. In this study we used 132 strains of H. influenzae, 89 strains of H. parainfluenzae and 43 strains of H. parahaemolyticus isolated during January and June of 1975, and estimated the susceptibility for the following eighteen antibiotics by the agar plate dilution method: ampicillin, amoxicillin, ciclacillin, sulbenicillin, carbenicillin, cephalothin, cefazolin, ceftezole, cephalexin, streptomycin, kanamycin, gentamicin, dibekacin, tetracycline, doxycycline, chloramphenicol, thiamphenicol and colistin. We compared these with previously reported results and observed the changes of antibiotic susceptibility. Ampicillin has the strongest antibiotic activity on three species of Haemophilus and the activity of four cephalosporins was weakest. Among three species H. parahaemolyticus was most susceptible and H. influenzae least susceptible to cephalosporins. Antibiotic activity of cyclacillin was rather weak. Other twelve antibiotics have good activity on Haemophilus. We could not find any ampicillin-resistant strain, but found five (3.8%) streptomycin-resistant, one (0.8%) kanamycin-resistant, eleven (8.3%) tetracycline-resistant, and seven (5.3%) chloramphenicol-resistant strains of H. influenzae. Six years ago we found five (9.6%) streptomycin-resistant and one (1.9%) tetracycline-resistant strains, but no resistant strain to other antibiotics. Tetracycline- and chloramphenicol-resistant strains are supposed to have a tendency to increase. There were very few strains which were resistant to more than two antibiotics among H. influenzae. We found a few strains resistant to tetracycline or chloramphenicol among H. parainfluenzae and H. parahaemolyticus, and one strain of H. parainfluenzae was less susceptible to ampicillin.

  16. Development and characterisation of highly antibiotic resistant Bartonella bacilliformis mutants.

    PubMed

    Gomes, Cláudia; Martínez-Puchol, Sandra; Ruiz-Roldán, Lidia; Pons, Maria J; Del Valle Mendoza, Juana; Ruiz, Joaquim

    2016-09-26

    The objective was to develop and characterise in vitro Bartonella bacilliformis antibiotic resistant mutants. Three B. bacilliformis strains were plated 35 or 40 times with azithromycin, chloramphenicol, ciprofloxacin or rifampicin discs. Resistance-stability was assessed performing 5 serial passages without antibiotic pressure. MICs were determined with/without Phe-Arg-β-Napthylamide and artesunate. Target alterations were screened in the 23S rRNA, rplD, rplV, gyrA, gyrB, parC, parE and rpoB genes. Chloramphenicol and ciprofloxacin resistance were the most difficult and easiest (>37.3 and 10.6 passages) to be selected, respectively. All mutants but one selected with chloramphenicol achieved high resistance levels. All rifampicin, one azithromycin and one ciprofloxacin mutants did not totally revert when cultured without antibiotic pressure. Azithromycin resistance was related to L4 substitutions Gln-66 → Lys or Gly-70 → Arg; L4 deletion Δ62-65 (Lys-Met-Tyr-Lys) or L22 insertion 83::Val-Ser-Glu-Ala-His-Val-Gly-Lys-Ser; in two chloramphenicol-resistant mutants the 23S rRNA mutation G2372A was detected. GyrA Ala-91 → Val and Asp-95 → Gly and GyrB Glu474 → Lys were detected in ciprofloxacin-resistant mutants. RpoB substitutions Gln-527 → Arg, His-540 → Tyr and Ser-545 → Phe plus Ser-588 → Tyr were detected in rifampicin-resistant mutants. In 5 mutants the effect of efflux pumps on resistance was observed. Antibiotic resistance was mainly related to target mutations and overexpression of efflux pumps, which might underlie microbiological failures during treatments.

  17. Intermediate Susceptibility to Ciprofloxacin among Salmonella enterica Serovar Typhi Isolates in Lima, Peru

    PubMed Central

    Lejon, Veerle; Horna, Gertrudis; Astocondor, Lizeth; Vanhoof, Raymond; Bertrand, Sophie; Jacobs, Jan

    2014-01-01

    Thirty-three Salmonella enterica serovar Typhi blood isolates from Lima, Peru (2008 to 2012), were fully susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, ceftriaxone, and tetracycline; 8/33 (24.2%) showed intermediate susceptibility to ciprofloxacin carrying mutations in the quinolone resistance-determining region of the gyrA gene (Ser83-Phe and Asp87-Asn) and in the gyrB gene (Ser464-Phe). PMID:24371234

  18. Multiple antibiotic resistance among gram negative bacteria isolated from poultry.

    PubMed

    Ansari, F A; Khatoon, H

    1994-03-01

    Gram negative bacteria, including species of Salmonella, Escherichia, Pseudomonas and Klebsiella, isolated from poultry, were screened for their resistance to the commonly used antibiotics: ampicillin, chloramphenicol, gentamycin, kanamycin, neomycin, polymyxin B, streptomycin and tetracycline. Of the 500 bacteria screened, 351 were found to be resistant to one or more antibiotics at the level of 50 micrograms/ml. Various patterns of antibiotic resistance observed during these studies have been reported.

  19. Development and characterisation of highly antibiotic resistant Bartonella bacilliformis mutants

    PubMed Central

    Gomes, Cláudia; Martínez-Puchol, Sandra; Ruiz-Roldán, Lidia; Pons, Maria J.; del Valle Mendoza, Juana; Ruiz, Joaquim

    2016-01-01

    The objective was to develop and characterise in vitro Bartonella bacilliformis antibiotic resistant mutants. Three B. bacilliformis strains were plated 35 or 40 times with azithromycin, chloramphenicol, ciprofloxacin or rifampicin discs. Resistance-stability was assessed performing 5 serial passages without antibiotic pressure. MICs were determined with/without Phe-Arg-β-Napthylamide and artesunate. Target alterations were screened in the 23S rRNA, rplD, rplV, gyrA, gyrB, parC, parE and rpoB genes. Chloramphenicol and ciprofloxacin resistance were the most difficult and easiest (>37.3 and 10.6 passages) to be selected, respectively. All mutants but one selected with chloramphenicol achieved high resistance levels. All rifampicin, one azithromycin and one ciprofloxacin mutants did not totally revert when cultured without antibiotic pressure. Azithromycin resistance was related to L4 substitutions Gln-66 → Lys or Gly-70 → Arg; L4 deletion Δ62–65 (Lys-Met-Tyr-Lys) or L22 insertion 83::Val-Ser-Glu-Ala-His-Val-Gly-Lys-Ser; in two chloramphenicol-resistant mutants the 23S rRNA mutation G2372A was detected. GyrA Ala-91 → Val and Asp-95 → Gly and GyrB Glu474 → Lys were detected in ciprofloxacin-resistant mutants. RpoB substitutions Gln-527 → Arg, His-540 → Tyr and Ser-545 → Phe plus Ser-588 → Tyr were detected in rifampicin-resistant mutants. In 5 mutants the effect of efflux pumps on resistance was observed. Antibiotic resistance was mainly related to target mutations and overexpression of efflux pumps, which might underlie microbiological failures during treatments. PMID:27667026

  20. Prevalence, antibiotic resistance and RAPD typing of Campylobacter species isolated from ducks, their rearing and processing environments in Penang, Malaysia.

    PubMed

    Adzitey, Frederick; Rusul, Gulam; Huda, Nurul; Cogan, Tristan; Corry, Janet

    2012-03-15

    We report for the first time on the prevalence, antibiotic resistance and RAPD types of Campylobacter species in ducks and duck related environmental samples in Malaysia. Samples were examined by enrichment in Bolton Broth followed by plating onto modified Charcoal Cefoperazone Deoxycholate agar (mCCDA) and/or plating directly onto mCCDA. A total of 643 samples were screened, and the prevalence of Campylobacter spp. in samples from different sources ranged from 0% to 85%. The method of isolation had a significant (P<0.05) effect on the isolation rate. One hundred and sixteen Campylobacter isolates, comprising of 94 Campylobacter jejuni, 19 Campylobacter coli and three Campylobacter lari, were examined for their sensitivity to 13 antibiotics. Majority of the C. jejuni isolates were resistant to cephalothin (99%), tetracycline (96%), suphamethoxazole/trimethoprim (96%), and very few were resistant to gentamicin (5%), chloramphenicol (7%) and erythromycin (1%). All C. coli isolates were resistant to cephalothin, nalidixic acid, norfloxacin and tetracycline but susceptible to chloramphenicol, erythromycin and gentamicin. The three C. lari isolates were resistant to all the antibiotics tested except chloramphenicol and gentamicin (1/3 and 2/3 susceptible, respectively). Genetic diversity of Campylobacter isolates were determined using random amplification of polymorphic DNA (RAPD). C. jejuni and C. coli isolates belong to fifty-eight and twelve RAPD types, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Characterization of antimicrobial-resistant phenotypes and genotypes among Salmonella enterica recovered from pigs on farms, from transport trucks, and from pigs after slaughter.

    PubMed

    Gebreyes, Wondwossen A; Davies, Peter R; Turkson, Paa-Kobina; Morrow, W E; Funk, Julie A; Altier, Craig; Thakur, Siddhartha

    2004-04-01

    The main objectives of this study were to determine antimicrobial resistance patterns among Salmonella serotypes and to evaluate the role of transport trucks in dissemination of antimicrobial-resistant strains of Salmonella. Salmonella from groups of nursery and finishing pigs on farms, from trucks, and from pigs after slaughter were compared using serotyping, patterns of antimicrobial resistance, and pulsed-field gel electrophoresis patterns. The five farms included in the study yielded 858 isolates representing 27 Salmonella serovars. The most common resistance observed (80% of all isolates) was to tetracycline; resistance to ampicillin (42%), chloramphenicol (31%), amoxicillin/clavulanic acid (30%), and piperacillin (31%) also were common. We found a correlation between serovar and antimicrobial resistance. High correlation was found between Salmonella Typhimurium var. Copenhagen and chloramphenicol resistance (Spearman rank correlation, rho = 0.7). Multidrug resistance was observed primarily in Salmonella Typhimurium var. Copenhagen (94%) and Salmonella Typhimurium (93%) and was much less common in the other common serovars, including Salmonella Derby (7%) and Salmonella Heidelberg (8%). Of the 225 isolates exhibiting the most common pentaresistance pattern in this study, amoxicillin/clavulanic acid-ampicillin-chloramphenicol-piperacillin-tetracycline, 220 (98%) were Salmonella Typhimurium var. Copenhagen, and 86% of the isolates of this serovar had this pattern. Isolates from the trucks were similar, based on pulsed-field gel electrophoresis patterns, to those from the cecum and mesenteric lymph nodes of pigs on two of the farms, suggesting the probable infection of pigs during transport. Class I integrons were also common among various serovars.

  2. Inactivation and regrowth of antibiotic-resistant bacteria by PAA disinfection in the secondary effluent of a municipal wastewater treatment plant.

    PubMed

    Huang, Jing Jing; Xi, Jing Ying; Hu, Hong Ying; Tang, Fang; Pang, Yu Chen

    2013-10-01

    Inactivation and microbial regrowth of penicillin-, ampicillin-, cefalexin-, tetracycline-, chloramphenicol-, and rifampicin-resistant bacteria were studied to explore risks associated with selection and regrowth of antibiotic-resistant bacteria after PAA disinfection. The results showed that after exposure to 20 mg/L PAA for 10 min, inactivation of ampicillin-resistant bacteria reached 2.3-log, which was significantly higher than that of total heterotrophic bacteria with a decrease of 2.0-log. In contrast, inactivation of tetracycline- resistant bacteria was significantly less efficient, reaching only 1.1-log. Chloramphenicol-and tetracycline-resistant bacteria, as well as total heterotrophic bacteria regrew more than 10 fold compared to those in the untreated wastewater sample with 22 h stilling culture after exposure to 2 or 5 mg/L PAA as for 10 min. Selection and potential regrowth of tetracycline-and chloramphenicol-resistant bacteria are potential risks when utilizing PAA disinfection, which may induce the spread of specific antibiotic-resistant bacteria in reclaimed water.

  3. Adverse Effects of Antimicrobials via Predictable or Idiosyncratic Inhibition of Host Mitochondrial Components

    PubMed Central

    Barnhill, Alison E.; Brewer, Matt T.

    2012-01-01

    This minireview explores mitochondria as a site for antibiotic-host interactions that lead to pathophysiologic responses manifested as nonantibacterial side effects. Mitochondrion-based side effects are possibly related to the notion that these organelles are archaic bacterial ancestors or commandeered remnants that have co-evolved in eukaryotic cells; thus, this minireview focuses on mitochondrial damage that may be analogous to the antibacterial effects of the drugs. Special attention is devoted to aminoglycosides, chloramphenicol, and fluoroquinolones and their respective single side effects related to mitochondrial disturbances. Linezolid/oxazolidinone multisystemic toxicity is also discussed. Aminoglycosides and oxazolidinones are inhibitors of bacterial ribosomes, and some of their side effects appear to be based on direct inhibition of mitochondrial ribosomes. Chloramphenicol and fluoroquinolones target bacterial ribosomes and gyrases/topoisomerases, respectively, both of which are present in mitochondria. However, the side effects of chloramphenicol and the fluoroquinolones appear to be based on idiosyncratic damage to host mitochondria. Nonetheless, it appears that mitochondrion-associated side effects are a potential aspect of antibiotics whose targets are shared by prokaryotes and mitochondria—an important consideration for future drug design. PMID:22615289

  4. Antibiotic combinations for controlling colistin-resistant Enterobacter cloacae.

    PubMed

    Lima, Thais Bergamin; Silva, Osmar Nascimento; de Almeida, Keyla Caroline; Ribeiro, Suzana Meira; Motta, Dielle de Oliveira; Maria-Neto, Simone; Lara, Michelle Brizolla; Filho, Carlos Roberto Souza; Ombredane, Alicia Simalie; de Faria Junior, Celio; Parachin, Nadia Skorupa; Magalhães, Beatriz Simas; Franco, Octávio Luiz

    2017-02-01

    Enterobacter cloacae is a Gram-negative bacterium associated with high morbidity and mortality in intensive care patients due to its resistance to multiple antibiotics. Currently, therapy against multi-resistant bacteria consists of using colistin, in spite of its toxic effects at higher concentrations. In this context, colistin-resistant E. cloacae strains were challenged with lower levels of colistin combined with other antibiotics to reduce colistin-associated side effects. Colistin-resistant E. cloacae (ATCC 49141) strains were generated by serial propagation in subinhibitory colistin concentrations. After this, three colistin-resistant and three nonresistant replicates were isolated. The identity of all the strains was confirmed by MALDI-TOF MS, VITEK 2 and MicroScan analysis. Furthermore, cross-resistance to other antibiotics was checked by disk diffusion and automated systems. The synergistic effects of the combined use of colistin and chloramphenicol were observed via the broth microdilution checkerboard method. First, data here reported showed that all strains presented intrinsic resistance to penicillin, cephalosporin (except fourth generation), monobactam, and some associations of penicillin and β-lactamase inhibitors. Moreover, a chloramphenicol and colistin combination was capable of inhibiting the induced colistin-resistant strains as well as two colistin-resistant clinical strains. Furthermore, no cytotoxic effect was observed by using such concentrations. In summary, the data reported here showed for the first time the possible therapeutic use of colistin-chloramphenicol for infections caused by colistin-resistant E. cloacae.

  5. Synthesis and evaluation of inhibitors of bacterial drug efflux pumps of the major facilitator superfamily.

    PubMed

    Okandeji, Babajide O; Greenwald, Daniel M; Wroten, Jessica; Sello, Jason K

    2011-12-15

    Inhibitors of drug efflux pumps have great potential as pharmacological agents that restore the drug susceptibility of multidrug resistant bacterial pathogens. Most attention has been focused on the discovery of small molecules that inhibit the resistance nodulation division (RND) family drug efflux pumps in Gram-negative bacteria. The prototypical inhibitor of RND-family efflux pumps in Gram-negative bacteria is MC-207,110 (Phe-Arg-β-naphthylamide), a C-capped dipeptide. Here, we report that C-capped dipeptides inhibit two chloramphenicol-specific efflux pumps in Streptomyces coelicolor, a Gram-positive bacterium that is a relative of the human pathogen Mycobacterium tuberculosis. Diversity-oriented synthesis of a library of structurally related C-capped dipeptides via an Ugi four component reaction and screening of the resulting compounds resulted in the discovery of a compound that is threefold more potent as a suppressor of chloramphenicol resistance in S. coelicolor than MC-207,110. Since chloramphenicol resistance in S. coelicolor is mediated by major facilitator superfamily drug efflux pumps, our findings provide the first evidence that C-capped dipeptides can inhibit drug efflux pumps outside of the RND superfamily.

  6. Antibiotic-dependent induction of Pseudomonas putida DOT-T1E TtgABC efflux pump is mediated by the drug binding repressor TtgR.

    PubMed

    Terán, Wilson; Felipe, Antonia; Segura, Ana; Rojas, Antonia; Ramos, Juan-Luis; Gallegos, María-Trinidad

    2003-10-01

    Pseudomonas putida is well known for its metabolic capabilities, but recently, it has been shown to exhibit resistance to a wide range of antibiotics. In P. putida DOT-T1E, the TtgABC efflux pump, which has a broad substrate specificity, extrudes antibiotics such as ampicillin, carbenicillin, tetracycline, nalidixic acid, and chloramphenicol. We have analyzed the expression of the ttgABC efflux pump operon and its regulatory gene, ttgR, in response to several structurally unrelated antibiotics at the transcriptional level and investigated the role of the TtgR protein in this process. ttgABC and ttgR are expressed in vivo at a moderate basal level, which increases in the presence of hydrophobic antibiotics like chloramphenicol and tetracycline. In vitro experiments show that, in the absence of inducers, TtgR binds to a palindromic operator site which overlaps both ttgABC and ttgR promoters and dissociates from it in the presence of chloramphenicol and tetracycline. These results suggest that the TtgR repressor is able to bind to structurally different antibiotics, which allows induction of TtgABC multidrug efflux pump expression in response to these antimicrobial agents. This is the first case in which the expression of a drug transporter of the resistance-nodulation-division family has been shown to be regulated directly by antibiotics.

  7. Physiological Aspects of Modification and Restoration of Chromosomal Synthesis in Bacteria After X Irradiation

    PubMed Central

    Billen, Daniel; Hewitt, Roger

    1965-01-01

    Billen, Daniel (The University of Texas, Houston), and Roger Hewitt. Physiological aspects of modification and restoration of chromosomal synthesis in bacteria after X irradiation. J. Bacteriol. 90:1218–1225. 1965.—A study was made of the effect of amino acid deprivation or chloramphenicol on the character of postirradiation deoxyribonucleic acid (DNA) replication in bacteria with the use of radioisotopes and 5-bromouracil as a density label. CsCl density-gradient studies of DNA showed that postirradiation incubation of amino acid-requiring Escherichia coli in an amino acid-free medium interfered with continued linear chromosomal replication. In the presence of the required amino acids, linear chromosomal replication was shown to resume. Addition of chloramphenicol was found to prevent this resumption. Deletion of the required amino acids or the presence of chloramphenicol in a fully supplemented medium allowed the detection of altered DNA synthesis in bacteria at X-ray doses as low as 500 r. The character of the limited DNA made in the presence of the density label after irradiation is described. The results are interpreted as showing that the synthesis of a protein(s) is required for restoration of linear chromosomal replication in the irradiated cells. PMID:5321477

  8. Synthesis and Assessment of Antibacterial Activities of Ruthenium(III) Mixed Ligand Complexes Containing 1,10-Phenanthroline and Guanide

    PubMed Central

    Hailemariam, Tizazu

    2016-01-01

    In this work, two complexes of ruthenium(III) ([Ru(phen)2Cl2]Cl·2H2O and [Ru(phen)2(G)Cl]2Cl·H2O) were synthesized from 1,10-phenanthroline alone as well as from both 1,10-phenanthroline and guanide. The synthesis was checked using halide test, conductance measurement, and spectroscopic (ICP-OES, FTIR, and UV/Vis) analysis. Their in vitro antibacterial activities were also investigated on two Gram-positive (Staphylococcus aureus (S. aureus) and methicillin resistant Staphylococcus aureus (MRSA)) and two Gram-negative (Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae)) bacteria. These complexes showed wide-range better activities than the commercially available controls (Chloramphenicol and Ciprofloxacin) against even the most drug resistant K. pneumoniae. [Ru(phen)2(G)Cl]2Cl·H2O inhibited S. aureus, MRSA, E. coli, and K. pneumoniae by 17.5%, 27.4%, 16%, and 52%, respectively, better than Chloramphenicol. It also inhibited these pathogens by 5.9%, 5.1%, 2.3%, and 17.2%, respectively, better than Ciprofloxacin. Similarly, [Ru(Phen)2(Cl)2]Cl·2H2O inhibited these pathogens by 11%, 8.7%, 0.1%, and 31.2%, respectively, better than Chloramphenicol. Therefore, after in vivo cytotoxicity investigations, these compounds can be considered as potential antibiotic drugs. PMID:27833473

  9. Influence of antibiotics on formylmethionyl-leucyl-phenylalanine-induced leukocyte chemiluminescence.

    PubMed Central

    Briheim, G; Dahlgren, C

    1987-01-01

    The effect of three antimicrobial agents, penicillin G, ampicillin, and chloramphenicol, on luminol-enhanced chemiluminescence of polymorphonuclear leukocytes stimulated by the chemoattractant formylmethionyl-leucyl-phenylalanine was studied. An inhibitory effect of penicillin G and of ampicillin was demonstrated, whereas chloramphenicol gave rise to an enhancement of the chemiluminescence response from polymorphonuclear leukocytes. These effects could be due to interaction between the drugs and the polymorphonuclear leukocytes, but they could also be the result of interference with the generation of light without any effect on the cells. Therefore, the effects of the same antimicrobial agents on the chemiluminescence generated from a cell-free system consisting of myeloperoxidase and hydrogen peroxide were investigated in parallel. The results obtained in the cell-free system were almost identical to those obtained in the cell system; i.e., penicillin G and ampicillin caused an inhibition and chloramphenicol caused an enhancement of the light emission. These results indicate that observed effects induced by drugs in a chemiluminescence assay are not necessarily due to interaction between the drug and polymorphonuclear leukocytes but may be caused by interference with other components of the assay. In view of these findings, the conflicting data reported in the literature on the effects of antimicrobial agents on phagocyte function are discussed. PMID:3606075

  10. PubMed Central

    Archimbault, P.; Boutier, C.; Fellous, R.

    1980-01-01

    Serum concentrations and factors affecting the blood bioavailability of chloramphenicol in bovine The authors have compared the serum concentrations and the factors affecting blood bioavailability of chloramphenicol after intramuscular administration of canadian commercial preparations containing 500 mg/mL of antibiotic. The animals (dairy cows and heifers) received each drug (20 mg/kg) in one or two injection sites. The serum samples, analysed by colorimetric or microbiological methods, showed that considerable differences in concentration exist between the two methods. The evolution of biodisponibility factors proved identical in both cases. It appears that therapeutic levels of chloramphenicol are reached only by drug A for four to five hours. The usual dosage (2-10 mg/kg), by intramuscular route, is not sufficient to attain these active concentrations using the other drugs. However, the important variability obtained during the experiment and reflected in the standard deviation values, has not proved that drug A has a better bioavailability based on the criteria of the only microbiological analysis. PMID:7260826

  11. Mediterranean spotted fever: clinical and laboratory characteristics of 415 Sicilian children

    PubMed Central

    Colomba, Claudia; Saporito, Laura; Polara, Valentina Frasca; Rubino, Raffaella; Titone, Lucina

    2006-01-01

    Background Mediterranean spotted fever (MSF) is an acute febrile, zoonotic disease caused by Rickettsia conorii and transmitted to humans by the brown dogtick Rhipicephalus sanguineus. Nearly four hundred cases are reported every year (mainly from June to September) on the Italian island of Sicily. The aim of the study was to analyze the clinical and laboratory characteristics of patients with MSF and the efficacy of the drugs administered. Methods Our study was carried out on 415 children with MSF, during the period January 1997 – December 2004, at the "G. Di Cristina" Children's hospital in Palermo, Sicily, Italy. On admission patients' clinical history, physical and laboratory examination and indirect immunofluorescence antibody test (IFAT) for Rickettsia conorii were performed. Diagnosis was considered confirmed if the patients had an MSF diagnostic score greater than or equal to 25 according to the Raoult's scoring system. All patients were treated with chloramphenicol or with macrolides (clarithromycin or azithromycin). Results Fever, rash and tache noire were present in 386 (93%), 392 (94.5%) and 263 (63.4%) cases respectively. Eighteen (4.6%) children showed atypical exanthema. Chloramphenicol and newer macrolides all appeared to be effective and safe therapies. Conclusion Clinical features of 415 children with MSF were similar to those reported by other authors except for a lower incidence of headache, arthralgia and myalgia and a higher frequency of epato-splenomegaly. Concerning therapy, clarithromycin can be considered a valid alternative therapy to tetracyclines or chloramphenicol especially for children aged < eight years. PMID:16553943

  12. Comparison of antimicrobial resistance in Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes strains isolated from organic and conventional poultry meat.

    PubMed

    Miranda, J M; Vázquez, B I; Fente, C A; Calo-Mata, P; Cepeda, A; Franco, C M

    2008-12-01

    The presence of Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes was determined in 55 samples of organic poultry meat and in 61 samples of conventional poultry meat. A total of 220 E. coli, 192 S. aureus, and 71 L. monocytogenes strains were analyzed by an agar disk diffusion assay for their resistance to ampicillin, cephalothin, chloramphenicol, ciprofloxacin, doxycycline, fosfomycin, gentamicin, nitrofurantoin, streptomycin, and sulfisoxazole (E. coli); chloramphenicol, ciprofloxacin, clindamycin, doxycycline, erythromycin, gentamicin, nitrofurantoin, oxacillin, and sulfisoxazole (S. aureus); and chloramphenicol, doxycycline, erythromycin, gentamicin, sulfisoxazole, and vancomycin (L. monocytogenes). The results indicated a significantly higher (P < 0.0001) prevalence of E. coli but not of S. aureus and L. monocytogenes in organic poultry meat as compared with conventional poultry meat. E. coli isolated from organic poultry meat exhibited lower levels of antimicrobial resistance against 7 of the 10 antimicrobials tested as compared with isolates recovered from conventional meat. In the case of S. aureus and L. monocytogenes isolated from conventional poultry, antimicrobial resistance was significantly higher only for doxycycline as compared with strains isolated from organic poultry. In the case of E. coli, the presence of multiresistant strains was significantly higher (P < 0.0001) in conventional poultry meat as compared with organic poultry meat. Organically farmed poultry samples showed significantly lower development of antimicrobial resistance in intestinal bacteria such as E. coli.

  13. Breath hydrogen concentration and small intestinal malabsorption in calves.

    PubMed

    Holland, R E; Herdt, T H; Refsal, K R

    1986-09-01

    Breath hydrogen concentrations were measured to assess intestinal carbohydrate malabsorption in preruminating calves. Oral administration of 1.25 g of lactulose (a nonabsorbable carbohydrate)/kg to calves produced breath hydrogen concentrations significantly (P less than 0.001) higher than values determined after calves were fed milk and before the treatment was given. This indicates that, in the calf, fermentation of nonabsorbed carbohydrates results in increased breath hydrogen values. To induce small intestinal malabsorption, chloramphenicol was administered orally at 50 mg/kg, 2 times a day, to 5 calves for 3 days. Before therapy was started, each calf was fitted with a duodenal cannula to facilitate collection of intestinal mucosal biopsy samples during treatment. Chloramphenicol therapy significantly (P less than 0.001) increased breath hydrogen concentrations from those values measured after calves were fed milk alone. Concurrently, chloramphenicol administration significantly decreased intestinal villous length (P less than 0.001) and D-xylose absorption (P less than 0.05), compared with those values before treatment was given. These results demonstrate that decreased intestinal absorptive capacity is associated with an increase in breath hydrogen concentrations and that breath hydrogen may be useful in evaluating malabsorption in calves with naturally occurring enteric disease.

  14. Human Immunodeficiency Virus Tat-Activated Expression of Poliovirus Protein 2A Inhibits mRNA Translation

    NASA Astrophysics Data System (ADS)

    Sun, Xiao-Hong; Baltimore, David

    1989-04-01

    To study the effect of poliovirus protein 2A on cellular RNA translation, the tat control system of human immunodeficiency virus (HIV) was used. Protein 2A was expressed from a plasmid construct (pHIV/2A) incorporating the HIV long terminal repeat. Protein synthesis was measured by using chloramphenicol acetyltransferase as a reporter gene driven by the Rous sarcoma virus long terminal repeat. When HIV/2A was contransfected with the reporter, addition of a tat-producing plasmid caused at least a 50-fold drop in chloramphenicol acetyltransferase synthesis. A HeLa cell line carrying HIV/2A was established. In it, tat expression caused more than a 10-fold drop in chloramphenicol acetyltransferase synthesis from the reporter plasmid. Furthermore, 2A induction by tat caused cleavage of the cellular translation factor P220, a part of eukaryotic translation initiation factor 4F. Thus protein 2A can, by itself, carry out the inhibition of cellular protein synthesis characteristic of a poliovirus infection. Also, the HIV tat activation provides a very effective method to control gene expression in mammalian cells.

  15. Studies of the development of congenital anomalies in rats. III. Effects of inhibition of mitochondrial energy systems on embryonic development.

    PubMed

    Mackler, B; Grace, R; Tippit, D F; Lemire, R J; Shepard, T H; Kelley, V C

    1975-12-01

    Pregnant rats were treated with various inhibitors of mitochondrial oxidative energy metabolism and with lowered oxygen tension, and the embryo fetuses examined for the occurrence of congenital malformations and for changes in enzymatic activities. Treatment with all agents tested resulted in the production of skeletal anomalies. Sodium phenobarbital was the most teratogenic of the drugs tested and produced a high incidence of malformations which included cleft palate, tail anomalies, spinal retroflexion, domed head, and facial hypoplasia. Diphenylhydantoin produced a low incidence of syndactyly and oligodactyly. In addition to its effects on fetal growth and development chloramphenicol appeared to interfere with implantation. Tissue preparations from embryos exposed to sodium phenobarbital and chloramphenicol showed markedly lowered levels of DPNH oxidase activity. Cytochrome oxidase activity was also markedly lowered in the preparations from chloramphenicol-exposed embryos. Enzyme activities in preparations from embryos exposed to malonate and diphenylhydantoin appeared unaffected, although the drugs are strong inhibitors of electron transport in vitro; the lack of apparent effect may be due to the fact that both drugs do not bind to the enzyme preparations and were diluted 100- to 200-fold during preparation and assay of the tissue homogenates.

  16. Antimicrobial susceptibility of Escherichia coli isolated from shrimp (Litopenaeus vannamei) and pond environment in northeastern Brazil.

    PubMed

    Vieira, Regine H S Dos F; Carvalho, Edirsana M R; Carvalho, Fatima C T; Silva, Camila M; Sousa, Oscarina V; Rodrigues, Dalia P

    2010-04-01

    This study aimed to test the susceptibility of Escherichia coli strains isolated from the water, bottom sediments and individuals cultivated in shrimp farm ponds, to antibiotics belonging to different families, namely B-Lactams: Imipenem (IPM; 10 micro g), Ampicillin (AMP; 10 micro g), Cephalothin (CEP; 30 micro g), Cefoxitin (FOX; 30 micro g), Ceftriaxone (CRO; 30 micro g); Tetracycline: Tetracycline (TCY; 30 micro g); Aminoglycosides: Gentamicin (GEN; 10 micro g), Amikacin (AMK; 30 micro g); Chloramphenicol: Chloramphenicol (CHO; 30 micro g); Fluoroquinolones: Ciprofloxacin (CIP; 5 micro g); Nitrofurans: Nitrofurantoin (NIT; 300 micro g); Sulfonamides: Trimethoprim-Sulfamethoxazole (SXT; 30 micro g); Quilononas: Nalidixic Acid (NAL; 30 micro g). In the laboratory, the method of dissemination (Test Kirby-Bauer) was performed in order to fulfill the antibiogram tests. The results showed high indices of resistance to Imipenem, Cephalothin and Ampicillin. Chloramphenicol, Nitrofurantoin, Cefoxitin, Ceftiaxone and Ciprofloxacin have displayed the highest index of sensitive strains. The antibiotic resistance index (ARI) and the multiple resistance index (MAR) varied within the ranges of 0.068-0.077 and 0.15-0.39, respectively. More than 90.5% of strains of Escherichia coli showed a variety of resistance profiles to the tested antibiotics. The high indices of resistance may be a consequence of indiscriminate use of antibiotics, but also the transfer of resistance through mobile genetic elements found in shrimp farms.

  17. Concurrence of cat and tet genes in multiple antibiotic-resistant bacteria isolated from a sea cucumber and sea urchin mariculture farm in China.

    PubMed

    Dang, Hongyue; Song, Linsheng; Chen, Mingna; Chang, Yaqing

    2006-11-01

    A basic understanding of abundance and diversity of antibiotic-resistant microbes and their genetic determinants is necessary for finding a way to prevent and control the spread of antibiotic resistance. For this purpose, chloramphenicol and multiple antibiotic-resistant bacteria were screened from a mariculture farm in northern China. Both sea cucumber and sea urchin rearing ponds were populated with abundant antibiotic-resistant bacteria, especially marine vibrios. Sixty-five percent chloramphenicol-resistant isolates from sea cucumber harbored a cat gene, either cat IV or cat II, whereas 35% sea urchin isolates harbored a cat gene, actually cat II. The predominant resistance determinant cat IV gene mainly occurred in isolates related to Vibrio tasmaniensis or Pseudoalteromonas atlantica, and the cat II gene mainly occurred in Vibrio splendidus-like isolates. All the cat-positive isolates also harbored one or two of the tet genes, tet(D), tet(B), or tet(A). As no chloramphenicol-related antibiotic was ever used, coselection of the cat genes by other antibiotics, especially oxytetracycline, might be the cause of the high incidence of cat genes in the mariculture farm studied.

  18. Effect of drug loading on the transformation of vesicular into cubic nanoparticles during heat treatment of aqueous monoolein/poloxamer dispersions.

    PubMed

    Wörle, Gert; Siekmann, Britta; Bunjes, Heike

    2006-06-01

    Colloidal dispersions of the pre-equilibrated cubic phase in the monoolein/poloxamer 407/water system, which are under investigation as potential drug carriers, often contain a considerable fraction of undesired non-cubic particles, particularly when prepared with high concentrations of poloxamer. Recent investigations revealed that the non-cubic particles can be transformed into particles of cubic internal structure by heat treatment. The present study investigates the effect of drug loading on the non-cubic to cubic transformation process during autoclaving of the dispersions. The results indicate that the process can also proceed in dispersions loaded with different concentrations of ubidecarenone, tocopheryl acetate, betamethasone-17-valerate, chloramphenicol or miconazole. At low concentration, none of the drugs had pronounced influence on the autoclaved dispersions whereas with increasing drug concentration different effects were observed. Depending on the type of drug no effects (betamethasone-17-valerate), increasing particle size of the dispersions (chloramphenicol, miconazole) or phase separation upon autoclaving (high load of miconazole) was observed. Except for loading with high amounts of chloramphenicol, which led to the formation of cubic phase particles already without additional heat treatment, the properties of the thermally untreated dispersions were virtually unaffected by drug incorporation.

  19. [Changes of resistant phenotype and CRISPR/Cas system of four Shigella strains passaged for 90 times without antibiotics].

    PubMed

    Zhang, B; Hong, L J; Duan, G C; Liang, W J; Yang, H Y; Xi, Y L

    2017-02-10

    Objective: To explore the stability of resistant phenotypes and changes of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) gene system on four Shigella strains in the absence of antibiotics. Methods: Four clinical isolated Shigella strains that resistant to different antibiotics were consecutive passaged for 90 times without antibiotics. Agar dilution method was used to determine the minimum inhibitory concentration of Shigella strains. After sequence analysis with PCR, CRISPR Finder and Clustal X 2.1 were applied to identify the changes of CRISPR loci in the Shigella strains. Results: After the consecutive transfer of 90 generations, sensitivity to certain antibiotics of four Shigella strains with different drug resistant spectrums increased. Mel-sf1998024/zz resistance to ampicillin, cephalexin, cefotaxime, chloramphenicol decreased, mel-s2014026/sx resistance to norfloxacin, trimethoprim decreased, mel-sf2004004/sx drug resistance to ampicillin, cefuroxime, cefotaxime, chloramphenicol, trimethoprim decreased and mel-sf2013004/bj resistance to chloramphenicol decreased. The spacer of which matched gene codes Cas and its upstream repeat in 3'end of CRISPR3 got lost in mel-sf1998024/zz and mel-sf2013004/bj. Conclusions:Shigella strains could reduce or lose their resistance to some antibiotics after consecutive transfers, without the interference of antibiotics. CRISPR3 locus had dynamic spacers in Shigella strains while CRISPR3 locus and cas genes might have been co-evolved.

  20. AmpC promoter and attenuator mutations affect function of three Escherichia coli strains.

    PubMed

    Yu, Wang; Bing, Liu; Zhenhua, Li

    2009-09-01

    To investigate the correlation between mutations in promoter, attenuator, and the AmpC enzyme overproduction in Escherichia coli. ampC Promoters from 4 Escherichia coli clinical isolates were cloned upstream to the chloramphenicol acetyltransferase (CAT) gene in pCAT3 reporter plasmid. Promoter strengths were measured by chloramphenicol MIC and gene sequencing was done on the cloned ampC promoter and attenuator. The strength of promoters from AmpC hyperproducers were 8- to 64-fold higher than those from a low-level AmpC producers. In one of the high-strength promoters, the mutations were located at positions -32, +22, +26, +32 (attenuator), -76, and +79. In another promoter, the mutations were located at positions -88, -82, -18, -1, and +58. In the third promoter, mutations were found at positions -1, +58, -80, -73, -28, and +82. Mutations in Escherichia coli promoter and attenuator sequences promoted Chloramphenicol MICs, which may be the primary causal mechanism for resistance to beta-lactams antibiotics.