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1.
Poult Sci ; 95(7): 1702-1708, 2016 Jul 01.
Article in English | MEDLINE | ID: mdl-27118861

ABSTRACT

Purified egg white is an important ingredient in a number of baked and confectionary foods because of its foaming properties. However, yolk contamination in amounts as low as 0.01% can impede the foaming ability of egg white. In this study, we used Raman spectroscopy to evaluate the hypothesis that yolk contamination in egg white could be detected based on its molecular optical properties. Yolk contaminated egg white samples (n = 115) with contamination levels ranging from 0% to 0.25% (on weight basis) were prepared. The samples were excited with a 785 nm laser and Raman spectra from 250 to 3,200 cm(-1) were recorded. The Raman spectra were baseline corrected using an optimized piecewise cubic interpolation on each spectrum and then normalized with a standard normal variate transformation. Samples were randomly divided into calibration (n = 77) and validation (n = 38) data sets. A partial least squares regression (PLSR) model was developed to predict yolk contamination levels, based on the Raman spectral fingerprint. Raman spectral peaks, in the spectral region of 1,080 and 1,666 cm(-1), had the largest influence on detecting yolk contamination in egg white. The PLSR model was able to correctly predict yolk contamination levels with an R(2) = 0.90 in the validation data set. These results demonstrate the capability of Raman spectroscopy for detection of yolk contamination at very low levels in egg white and present a strong case for development of an on-line system to be deployed in egg processing plants.


Subject(s)
Chickens , Egg White/analysis , Egg Yolk/chemistry , Food Handling , Animals , Least-Squares Analysis , Spectrum Analysis, Raman
3.
J Antimicrob Chemother ; 40(2): 241-9, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9301990

ABSTRACT

The efficacy of 19 agar diffusion methods for the detection of methicillin resistance among coagulase-negative staphylococci (CoNS) within 24 h was evaluated. A total of 359 CoNS isolates were tested, of which 204 were Staphylococcus epidermidis. In 164 isolates, the presence of mecA was investigated; 61 strains were mecA-positive and 103 were mecA-negative by Southern blot analysis. Based on the best agreement shown with the mecA determination (94%) among four agar dilution assays for determining methicillin MIC, an assay with Columbia agar supplemented with NaCl and incubation with a heavy bacterial inoculum of 10(5)-10(6) cfu/spot was used as the reference MIC method. The best agar diffusion results were obtained with a 1 microg oxacillin disc on Columbia agar with 4.5% NaCl supplement. With this method, 99% of S. epidermidis and 94% of non-S. epidermidis were in agreement with the MIC determination. However, Columbia (without NaCl), Mueller-Hinton and Isosensitest agars were almost as useful when a 1 microg oxacillin disc was used. The zone breakpoints for S. epidermidis were, in general, considerably larger than those for other CoNS species and, consequently, differentiation according to species is recommended. Furthermore, resistance to other antibiotics, such as gentamicin and erythromycin, makes methicillin resistance highly likely.


Subject(s)
Bacterial Proteins , Hexosyltransferases , Methicillin Resistance , Methicillin/pharmacology , Microbial Sensitivity Tests , Penicillins/pharmacology , Peptidyl Transferases , Staphylococcus/drug effects , beta-Lactamases/metabolism , Carrier Proteins/genetics , Coagulase/metabolism , Evaluation Studies as Topic , Genes, Bacterial/genetics , Methicillin Resistance/genetics , Muramoylpentapeptide Carboxypeptidase/genetics , Penicillin-Binding Proteins , Staphylococcus/enzymology , Staphylococcus/genetics , Staphylococcus epidermidis/drug effects
4.
APMIS ; 104(2): 108-14, 1996 Feb.
Article in English | MEDLINE | ID: mdl-8619912

ABSTRACT

The in vitro susceptibility of 124 Xanthomonas maltophilia isolates was tested by four methods: Agar dilution (reference method), E-test, a disk diffusion and a tablet diffusion method. Trimethoprim-sulfamethoxazole had the highest activity against X. maltophilia, followed by a combination of aztreonam-clavulanic acid at different ratios, the ratio 1:1 being the most active with a susceptibility rate of 85% as compared to 2% for aztreonam alone. Addition of the beta-lactamase inhibitor tazobactam to piperacillin enhanced the rate of susceptible isolates from 31% to 53%, Relatively few isolates were susceptible to ciprofloxacin (27%) and gentamicin (9%). Generally, the disk diffusion method had a considerably higher frequency of "very major" discrepancies when compared with the agar dilution method than with the other methods. The susceptibility of X. maltophilia to trimethoprim-sulfamethoxazole and ciprofloxacin could reliably be determined by all the diffusion methods tested, but otherwise the agar dilution method is to be preferred. A standardized and reliable diffusion method for susceptibility testing of X. maltophilia remains to be found. Trimethoprim-sulfamethoxazole must be considered the drug of choice in the treatment of severe X. maltophilia infections. The combination aztreonam-clavulanic acid is promising, but must be proved in a clinical setting.


Subject(s)
Anti-Bacterial Agents/pharmacology , Xanthomonas/drug effects , Ceftazidime/pharmacology , Ciprofloxacin/pharmacology , Enzyme Inhibitors/pharmacology , Escherichia coli/drug effects , Gentamicins/pharmacology , Humans , Microbial Sensitivity Tests , Penicillanic Acid/analogs & derivatives , Penicillanic Acid/pharmacology , Piperacillin/pharmacology , Pseudomonas aeruginosa/drug effects , Staphylococcus aureus/drug effects , Tazobactam , Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology , Xanthomonas/isolation & purification , beta-Lactamase Inhibitors
5.
Pharmacol Toxicol ; 71(6): 449-51, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1362269

ABSTRACT

Eighty-two strains of bacteria (Neisseria meningitidis, Haemophilus influenzae, Enterobacteriaceae, Streptococcus pneumoniae, group B streptococci and Listeria monocytogenes) were examined for their in vitro susceptibility to eight drugs, seven neuroleptics (perphenazine, fluphenazine, cis(Z)-clopenthixol, haloperidol, clozapine, clebopride and SCH 23390), and the neuroleptically inactive trans(E)-clopenthixol. The phenothiazines and the thioxanthenes were, on the whole, the most active drugs when measured, the IC50(50) for each group of bacteria being 7.4 to 84 mg/l (with the exception of the activity against the enterobacteriaceae). The antibacterial potency of clozapine, which has an atypical neuroleptic profile, was between 50 and 140 mg/l. Haloperidol also showed an antibacterial activity in the concentration range 35-140 mg/l. The selective D1 antagonist, SCH 23390 and the selective D2 antagonist, clebopride, inhibited only few of the bacteria in the concentration range investigated.


Subject(s)
Antipsychotic Agents/pharmacology , Haemophilus influenzae/drug effects , Neisseria meningitidis/drug effects , Humans , Meningitis, Bacterial/cerebrospinal fluid , Meningitis, Bacterial/microbiology , Microbial Sensitivity Tests
6.
APMIS ; 99(6): 537-40, 1991 Jun.
Article in English | MEDLINE | ID: mdl-2054171

ABSTRACT

A total of 49 gentamicin-resistant strains of Staphylococcus aureus isolated from blood (n = 26) or from other sites (n = 23) during the years 1979 to 1987 were evaluated for the presence of aminoglycoside-inactivating enzymes on the basis of minimum inhibitory concentrations measured by agar dilution as well as inhibition zone diameters determined by disc diffusion. Enzymatic activity was caused by AAC (6')III/APH (2") in 45 strains, and by AAC (6')III/APH (2") + APH (3') in four strains. No changes in the distribution of enzymatic activity were observed during the eight years.


Subject(s)
Anti-Bacterial Agents/pharmacology , Staphylococcus aureus/drug effects , Aminoglycosides , Denmark , Drug Resistance, Microbial , Time Factors
7.
Scand J Infect Dis ; 23(3): 337-40, 1991.
Article in English | MEDLINE | ID: mdl-1882199

ABSTRACT

A system for surveillance of invasive Haemophilus influenzae type b infections in Denmark yielded 135 strains isolated from blood or cerebrospinal fluid from August 1988 through December 1989. The susceptibility of the strains to 7 antibiotics was investigated by an agar dilution method. Ceftriaxone was found to be the most active drug followed by cefotaxime, ceftazidime, rifampicin, ampicillin, cefuroxime, and chloramphenicol. Except for ampicillin the MICs for the individual antibiotics were similar. Seven strains (5.2%), which all produced beta-lactamase, were resistant to ampicillin. Since H. influenzae type b meningitis in otherwise healthy individuals almost exclusively occurs in children aged 2 months to 4 years, a third generation cephalosporin such as ceftriaxone or cefotaxime may be considered the drug of choice for initial therapy of meningitis in this age group.


Subject(s)
Anti-Bacterial Agents/pharmacology , Haemophilus influenzae/drug effects , Ampicillin Resistance , Bacterial Typing Techniques , Cephalosporins/pharmacology , Child, Preschool , Denmark , Haemophilus influenzae/enzymology , Humans , Infant , Meningitis, Haemophilus/microbiology , Microbial Sensitivity Tests , beta-Lactamases/metabolism
8.
J Antimicrob Chemother ; 22(2): 119-25, 1988 Aug.
Article in English | MEDLINE | ID: mdl-3263351

ABSTRACT

Forty-nine clinical strains of coagulase-negative staphylococci were investigated for susceptibility to methicillin, oxacillin, cloxacillin, dicloxacillin, flucloxacillin and cephalothin. The highest level of resistance was found to methicillin and the lowest to cephalothin. The resistance-level of the isoxazolyl penicillins showed a high degree of uniformity. However more strains were resistant to cloxacillin and oxacillin than to dicloxacillin and flucloxacillin. Only a weak correlation was found between beta-lactamase production, and resistance to the six antibiotics. Methicillin was the most stable. The inactivation of cephalothin differed from that of the other antibiotics.


Subject(s)
Cephalothin/pharmacology , Coagulase/metabolism , Methicillin/pharmacology , Penicillins/pharmacology , Staphylococcus/drug effects , beta-Lactamases/metabolism , Drug Resistance, Microbial , Staphylococcus/enzymology
10.
Acta Pathol Microbiol Immunol Scand B ; 95(6): 355-9, 1987 Dec.
Article in English | MEDLINE | ID: mdl-3439463

ABSTRACT

The antibacterial effect of the stereo-isomeric compounds cis(Z)- and trans(E)-clopenthixol and the two main metabolites of clopenthixol in man, N-dealkyl-clopenthixol and clopenthixol sulfoxide, was examined in 24 Gram-positive and 37 Gram-negative bacterial strains in vitro. The antibacterial potency of the drugs towards the Gram-positive strains, measured as IC50, was: N-dealkyl-clopenthixol, 6.2 microM (3.7 micrograms/ml), trans(E)-clopenthixol, 16 microM (7.6 micrograms/ml) and cis(Z)-clopenthixol, 37 microM (17.5 micrograms/ml), and clopenthixol sulfoxide was inactive in the investigated area. Against the Gram-negative strains the drugs are less potent. A therapeutic application of these results, especially in the case of trans(E)-clopenthixol, which possesses no neuroleptic activity, requires in vivo testing in an animal model. However, the in vitro model employed might also be useful in the study of such agents and other membrane-active compounds with regard to their interaction with biological membranes.


Subject(s)
Anti-Bacterial Agents , Clopenthixol/analogs & derivatives , Clopenthixol/pharmacology , Thioxanthenes/pharmacology , Gram-Negative Bacteria/drug effects , Microbial Sensitivity Tests , Species Specificity , Stereoisomerism , Structure-Activity Relationship
11.
Pharmacol Toxicol ; 60(2): 100-3, 1987 Feb.
Article in English | MEDLINE | ID: mdl-2883644

ABSTRACT

Various types of phenothiazines were examined for antibacterial effect on 61 Gram-positive and Gram-negative bacterial strains in vitro. The investigated phenothiazines were two neuroleptic drugs, fluphenazine and chlorpromazine, and two antihistaminic drugs, alimemazine and promethazine. All four drugs have antibacterial effects in vitro, the phenothiazines being more potent against the Gram-positive microorganisms. The antibacterial potency of the drugs was measured as IC50: Fluphenazine 29 microM (15 micrograms/ml), alimemzaine 49 microM (37 micrograms/ml), promethazine 88 microM (28 micrograms/ml) and chlorpromazine 92 microM (29 micrograms/ml). The antibacterial potency of the drugs was linked neither to the neuroleptic nor the antihistaminic potency of the drugs, which is in agreement with results of earlier stereoisomeric investigations. Thus, the known phenothiazines may represent a pool of potentially new antimicrobial drugs. A therapeutic application of these results, however, requires additional in vitro an in vivo testing in an animal model. The bacterial model might be of value as a model system in the study of the interaction of neuropharmacological agents and other membrane active compounds on biological membranes.


Subject(s)
Anti-Bacterial Agents , Phenothiazines/pharmacology , Antipsychotic Agents/pharmacology , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Histamine H1 Antagonists/pharmacology , Microbial Sensitivity Tests
12.
Acta Pathol Microbiol Immunol Scand B ; 94(3): 159-66, 1986 Jun.
Article in English | MEDLINE | ID: mdl-3090857

ABSTRACT

The purpose of the present study was to investigate the effect of 20-hour pre-diffusion, i.e. placing the antibiotic-containing discs on the agar for 20 hours prior to inoculation, as compared to direct diffusion, i.e. placing the discs on the agar immediately after inoculation, for the newer 3. generation cephalosporins as represented by ceftazidime and ceftriaxone. Regression lines (zone sizes vs. inhibitory concentrations, as measured by plate-dilution) were constructed for three groups of bacteria chosen because of their differences in growth characteristics on agar: E. coli (n = 50), Enterobacter sp. (n = 35), and streptococci (n = 51). The results for both cephalosporins were: 20-hour pre-diffusion produced larger zones than direct diffusion, regression studies for 20-hour pre-diffusion as compared to direct diffusion resulted in greater variation in zone sizes, numerically lower slopes, lower residual variances and higher correlation coefficients, and regression lines were significantly different for the 3 groups of bacteria with direct diffusion but not so with 20-hour pre-diffusion. Considering the interpretation of zone sizes with disc diffusion for the cephalosporins tested, 20-hour pre-diffusion was superior to direct diffusion.


Subject(s)
Ceftazidime/pharmacology , Ceftriaxone/pharmacology , Enterobacter/drug effects , Enterobacteriaceae/drug effects , Escherichia coli/drug effects , Streptococcus/drug effects , Enterococcus faecalis/drug effects , Microbial Sensitivity Tests , Regression Analysis , Streptococcus pneumoniae/drug effects
13.
Acta Pathol Microbiol Immunol Scand B ; 94(2): 103-6, 1986 Apr.
Article in English | MEDLINE | ID: mdl-3728025

ABSTRACT

The present investigation has been undertaken to illustrate the antibacterial effect on 20 diarrhoea producing enterobacteriaceae of an anti-depressive drug available as femoxetine and its three analogs. It has been shown that the stereo-isomeric trans forms of femoxetine are more than twice as active as the cis forms and inhibited all the strains below 400 microgram/ml (1.2 mM). The two cis compounds only inhibited 11 and 9 of the 20 strains respectively in the investigated area 100 microgram/ml - 800 microgram/ml (0.3 mM - 2.4 mM). Our investigations point out that the bacterial cell has a target for psychopharmacologically active agents. Thus the known psychopharmaca and their stereo-isomeric analogs may represent a pool of potentially new antimicrobial drugs. Furthermore the bacterial model may be useful as a model system in the study of the interaction of neuropharmacological agents and other membrane active compounds with biological membranes.


Subject(s)
Anti-Bacterial Agents , Enterobacteriaceae/drug effects , Piperidines/pharmacology , Diarrhea/microbiology , Humans , Stereoisomerism , Structure-Activity Relationship
14.
Acta Pathol Microbiol Immunol Scand B ; 93(3): 181-8, 1985 Jun.
Article in English | MEDLINE | ID: mdl-3929558

ABSTRACT

The antibacterial activity in vitro of ceftazidime and ceftriaxone was investigated against 575 recent clinical isolates. Both cephalosporins displayed excellent activity against most of the pathogens tested, in particular Gram-negative bacteria, including Pseudomonas aeruginosa. Apart from the Pseudomonas group, Acinetobacter calcoaceticus and Campylobacter jejuni ceftriaxone was slightly to moderately more active than ceftazidime overall. Ceftriaxone was moderately active against Streptococcus faecalis. Regression lines for the two antibiotics were almost identical. Corresponding to differences in susceptibility, the zone sizes differed for the two drugs with respect to certain bacterial groups, e.g. Pseudomonas sp. and enterococci. Therefore, the two cephalosporins cannot substitute for each other in disc susceptibility testing. Breakpoints for disc tests around 8-16 micrograms/ml, as suggested in the literature, appear too high considering the beneficial pharmacokinetic properties of the two drugs.


Subject(s)
Cefotaxime/analogs & derivatives , Ceftazidime/pharmacology , Enterobacteriaceae/drug effects , Pseudomonas aeruginosa/drug effects , Streptococcus/drug effects , Acinetobacter/drug effects , Acinetobacter/growth & development , Campylobacter fetus/drug effects , Campylobacter fetus/growth & development , Cefotaxime/pharmacology , Ceftriaxone , Cephalosporins/pharmacology , Enterobacteriaceae/growth & development , Enterococcus faecalis/drug effects , Enterococcus faecalis/growth & development , Microbial Sensitivity Tests , Pseudomonas aeruginosa/growth & development , Regression Analysis
15.
Biochim Biophys Acta ; 685(3): 379-82, 1982 Mar 08.
Article in English | MEDLINE | ID: mdl-7066316

ABSTRACT

The effect of different categories of membrane stabilizers on K+ loss and growth has been characterized in a culture of Staphylococcus aureus. Chlorpromazine, thiopental and tetracaine at low concentrations produced a marked inhibition of K+ loss and an equivalent increase in the K+ contents of S. aureus. Whereas the inhibitory effect of chlorpromazine on K+ loss was observed at lower than bacteriostatic concentrations of the drug, thiopental had no effect on growth in the concentration range where K+ loss was maximally inhibited. It is concluded that the bacteriostatic action of chlorpromazine is probably not related to its membrane stabilizing effect only.


Subject(s)
Chlorpromazine/pharmacology , Potassium/metabolism , Staphylococcus aureus/metabolism , Tetracaine/pharmacology , Thiopental/pharmacology , Cell Membrane/drug effects , Cell Membrane/metabolism , Kinetics , Staphylococcus aureus/drug effects
16.
Acta Pathol Microbiol Immunol Scand B ; 90(1): 25-35, 1982 Feb.
Article in English | MEDLINE | ID: mdl-6805249

ABSTRACT

A previously described model of experimental Streptococcus faecalis endocarditis in rabbits without an indwelling catheter during the infectious processes was used to study the effect of long-term treatment with antibiotics. Groups of animals infected with six different strains were treated for four weeks and the following parameters were determined: survival rate, bacterial concentration in blood and vegetations, signs at autopsy indicating congestive heart failure. Before the therapeutic experiments, the tolerance of the rabbit to long-term exposure of the drugs penicillin and streptomycin was considered in a group of non-infected animals. Two out of 20 rabbits died with enteritis during the penicillin exposure, and a general weight reduction was observed. Streptomycin was apparently completely harmless. There was no therapeutic effect of streptomycin on S. faecalis endocarditis due to strains all designated resistant to streptomycin by MIC, except in rabbits infected with a strain, which showed partial susceptibility to the drug by IC50. Regardless of the therapeutic effect, evidence was obtained for rapid development of increased resistance of the infecting strains towards streptomycin. After long-term treatment with penicillin in either low or high dose some of the animals survived and the valves were sterilized in 37% of the animals after low-dose and in 39% after high-dose. It was observed that congestive heart failure occurred with the greatest frequency and intensity after infection with proteolytic strains.


Subject(s)
Endocarditis, Bacterial/drug therapy , Penicillins/therapeutic use , Streptococcal Infections/drug therapy , Streptomycin/therapeutic use , Animals , Enterococcus faecalis/drug effects , Heart/microbiology , Microbial Sensitivity Tests , Organ Size , Penicillins/toxicity , Rabbits , Streptomycin/toxicity
18.
Acta Pathol Microbiol Scand B ; 89(6): 437-8, 1981 Dec.
Article in English | MEDLINE | ID: mdl-6121444

ABSTRACT

Measurement of the IC50 of cis(Z)-clopenthixol and trans(E)-clopenthixol on 188 bacterial strains from human clinical specimens shows that the antibacterial activity of clopenthixol is exerted by both isomerical components and trans(E)-clopenthixol is the most active antibiotic of the two drugs against the sensitive strains. It is known that the trans(E)-clopenthixol isomere is without neuroleptic effect. The possibility of creating new antibiotics by e.g. steric alteration of neuroleptical agents is stressed. These drugs have different antibiotic patterns from those of classical antibiotics. It seems particularly promising that Pseudomonas aeruginosa is sensitive to these drugs.


Subject(s)
Clopenthixol/pharmacology , Thioxanthenes/pharmacology , Anti-Bacterial Agents , Antipsychotic Agents , Microbial Sensitivity Tests , Pseudomonas aeruginosa/drug effects , Stereoisomerism
19.
J Toxicol Environ Health ; 8(5-6): 787-93, 1981.
Article in English | MEDLINE | ID: mdl-7338941

ABSTRACT

Two groups of Mongolian gerbils (Meriones unguiculatus) were continuously exposed to 150 ppm trichloroethylene (TCE) for 71 and 106 d, respectively. The behavior of the animals was tested in a symmetrical maze baited with sunflower seeds during a period of 23 d, beginning at the end of exposure. One additional group was exposed for 150 d and then allowed 40 d free from exposure before the start of the maze test. Comparisons between the TCE- and air-exposed animals showed differences in the number of correct choices and the number of seeds consumed in the maze, both after 71 and 106 d of exposure and at the end of the 40-d rehabilitation period that followed the 150-d exposure. The results were interpreted in terms of the "emotionality" of the animals.


Subject(s)
Behavior, Animal/drug effects , Trichloroethylene/toxicity , Animals , Eating/drug effects , Female , Gerbillinae , Male
20.
Toxicology ; 21(2): 105-15, 1981.
Article in English | MEDLINE | ID: mdl-7281199

ABSTRACT

The influence of continuous inhalation of 150 ppm trichloroethylene (TCE) on body, liver, spleen, and kidney weights in rats, mice, and mongolian gerbils was tested. An age dependent decrease in body weight gain was observed in female rats exposed to TCE. All 3 species showed liver enlargement caused by the exposure. The effect was much more pronounced in mice, in which the increase was 60--80%, than in rats and gerbils where it was only 20--30%. After the end of the TCE-exposure the liver weights of the mice decreased rapidly. After 5 days of rehabilitation the weight was only 10--20% higher than that of the controls. This difference persisted for at least 25 days. The spleen weight appeared unaffected or somewhat smaller in TCE-exposed animals of all species. An increased kidney weight (15%) was observe din TCE-exposed gerbils. This effect was less pronounced in mice and rats. Effects on the liver have earlier been seen only after exposure to concentrations much higher than that used in the present study. This difference in results is proposed to be due to the different schedules used for the exposure.


Subject(s)
Trichloroethylene/pharmacology , Animals , Body Weight/drug effects , Female , Gerbillinae , Male , Mice , Organ Size/drug effects , Rats , Rats, Inbred Strains , Sex Factors , Species Specificity
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