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Biomedical subjects

J Dankert

Publications and source records attributed to J Dankert.

At least 253 records · Page 14Linked to original sources
PubMed1983

Importance of minimizing carry-over effect at subculture in the detection of penicillin-tolerant viridans group streptococci.

Penicillin susceptibility determinations made for 14 strains of Streptococcus mitior by two different broth dilution tests revealed small numbers of tolerant strains regardless of the volumes (0.01 and 0.1 ml) of subcultured broth. The addition of penicillinase to the subculture medium increased the number of tolerant strains significantly in 0.1 ml of subcultured broth, demonstrating that the detection of penicillin-tolerant viridans group streptococci might be hampered by the carry-over of penicillin.

Microbial Sensitivity Tests↗
PubMed1983

Incidence of postextraction bacteremia under penicillin cover in children with cardiac disease.

To assess the efficacy of penicillin prophylaxis as recommended by the American Heart Association to prevent the onset of bacterial endocarditis, the incidence of postextraction bacteremia was determined in 82 children with cardiac disease who were receiving prophylactic penicillin. Aerobic and anaerobic blood cultures were taken five minutes after dental extraction, as was a blood sample to assay the serum penicillin concentration. The incidence of postextraction bacteremia was 21%. Streptococcal species accounted for half of the number of aerobes isolated. Of the isolated microorganisms, 16% were strict anaerobes. Susceptibility testing of the isolates showed that 24 penicillin-sensitive and eight penicillin-resistant microorganisms caused the bacteremia. There was neither a significant difference between the serum penicillin concentrations of children with and without bacteremia, nor between the serum penicillin concentrations of children with bacteremia due to penicillin-sensitive microorganisms and children with bacteremia due to penicillin-resistant microorganisms. It is concluded that the occurrence of postextraction bacteremia is not prevented by penicillin prophylaxis and that the serum penicillin concentration at extraction is not the discriminating factor in preventing this bacteremia. None of the children developed bacterial endocarditis. It is speculated that mechanisms not thoroughly studied are involved in the prevention of bacterial endocarditis after dental extraction.

Adolescent↗
PubMed1982

Urinary-tract infection and bacteraemia in hospitalized medical patients--a European multicentre prevalence survey on nosocomial infection.

A co-ordinated survey of 3899 medical patients in 169 wards, performed simultaneously in eight countries, showed a point-prevalence of urinary-tract infection (UTI) and bacteraemia of 12.6 and 1.6 per cent, respectively. One-half of the infections were acquired after the patients' admission. The bacteriological patterns of hospital- vs community-acquired infections were different, but showed no unexpected features. Antibiotic treatment was recorded in 22.3 per cent of the patients in this study, urinary-tract disinfectants, sulphonamides or penicillins being used in 95 per cent of those treated for UTI. The overall prevalence of urinary-tract drainage was 11.0 per cent with no significant difference between the two sexes. At ward level the rate of catheterized patients varied from below 5 per cent to more than 25 per cent, indicating--besides variations in the ward populations--differences in policies. The association between nosocomial UTI and the presence of an indwelling catheter and/or female sex was confirmed, while high age appeared to be a secondary risk factor among catheterized patients. The prevalence of nosocomial bacteraemia in patients with UTI was five times higher than in those without urinary-tract involvement, and a significant part of the nosocomial cases of both UTI and bacteraemia was clearly device-related. Guidelines for the use of indwelling catheters should be restrictive and provide for prompt removal. When introduced and followed they will effectively reduce nosocomial UTI and bacteraemia.

Age Factors↗
PubMed1982

Penicillin tolerance in nutritionally variant streptococci.

Eleven strains of nutritionally variant streptococci were tested for their susceptibility to penicillin by a broth dilution method. All minimal inhibitory concentrations were low. It was found that plates containing only vitamin B6 (pyridoxal HCl) and cysteine did not reveal true minimal bactericidal concentrations. When penicillinase was added to the subculture medium and a staphylococcal streak was made across the plates, all 11 strains were found to have high minimal bactericidal concentrations and were shown to be tolerant to penicillin.

Culture Media↗
PubMed1982

Screening for penicillin tolerance in viridans streptococci by a simple disk method.

A disk method was developed for demonstrating penicillin tolerance in viridans streptococci. This was achieved by the substitution of the penicillin disk used for susceptibility testing by a disk containing penicillinase. After reincubation, penicillin-tolerant strains exhibited new growth in the area adjacent to this disk, providing a rapid screening test.

Drug Tolerance↗
PubMed1981

Volatile fatty acids in human peripheral and portal blood: quantitative determination vacuum distillation and gas chromatography.

In order to determine volatile fatty acids (VFA) in human blood, gas chromatographic analyses were performed after blood samples had been pre-treated by a vacuum distillation procedure with subsequent evaporation. Results of the reproducibility study, investigated by pre-treating five aliquots of one human serum sample showed C.V. values ranging from 7.4 to 18.2. Normal serum VFA values were determined in individual serum samples collected from healthy subjects and compared to those present in serum from patients undergoing gall-bladder surgery. The serum VFA values were comparable in the two groups. In the surgical patients, blood was also collected from the portal circulation. All portal serum VFA values, except that of iso-butyric acid, were higher than those found in the samples collected from the peripheral arm vein. VFA values were also determined in serum specimens obtained from blood collected from the arm vein of patients with extensive cirrhosis of the liver. The VFA values showed marked individual variations and were higher than those found in peripheral samples from healthy subjects and patients undergoing gall-bladder surgery, but were lower than those found in samples from the portal circulation from the surgical patients.

Arm↗
PubMed1981

Quantitative measurements of the diffusion in vitro of some aldehydes in root canals of human teeth.

Quantitative measurements with Schiff reagent of the diffusion of aldehydes from endodontically prepared teeth were performed as a function of time, quantity, and concentration of the inserted drug, repeated sealing of the drug in the root canal, the age of the tooth, and the site of the diffusion. The measurements are based on the reaction of aldehydes with Schiff reagent. All teeth were permeable to formaldehyde-containing drugs. Diffusion of the formaldehyde could be detected within 1 minute. The bulk of the inserted formaldehyde diffused through the apical third, but in young teeth (less than 20 years) the whole root surface was permeable. A 2 percent solution of glutaraldehyde, unlike 10 and 25 percent studies, tended to permeate through the dentin and cementum.

Adolescent↗
PubMed1981

Porin from the outer membrane of Escherichia coli: immunological characterization of native and heat-dissociated forms.

Antisera against porin oligomers isolated from the outer membrane of Escherichia coli O26K60 and against porin monomers from the same bacterial strain were elicited in rabbits by intramuscular administration with Freund's complete adjuvant. Antibodies against native porin oligomers reacted strongly with porin oligomers, as revealed by sodium dodecyl sulphate-polyacrylamide gel immunoperoxidase (SGIP) analysis, the enzyme-linked immunosorbent assay (ELISA) and immunodiffusion, but showed no significant reaction with denatured monomers. The antibodies were completely absorbed by the intact outer membrane-peptidoglycan complex, which suggests that they were directed against antigenic determinants expressed on the outside of the intact outer membrane. Antibodies directed against denatured porin monomers reacted strongly with monomers in all tests but reacted only very weakly with porin oligomers. They were not absorbed by the native porin situated in the intact outer membrane. This indicates that the major antigenic determinants of the denatured porin monomer are hardly related to those of the native trimer situated in the intact outer membrane. The antigenic determinants of the denatured monomer seem to become fully expressed only after dissociation and denaturation of the porin. It is concluded that the immunological relationship of denatured porin monomers derived from many strains of E. coli and other Enterobacteriaceae which was reported in previous studies may not indicate that native porin trimers of these strains are also related.

Antibodies, Bacterial↗
PubMed1981

Comparative clinical evaluation of the effect of sucrose in a new anaerobic blood culture medium.

In order to study the effect of excess sucrose on microorganisms, growth curves of 5 anaerobic and 5 aerobic microorganisms were performed in Diagnostic Anaerobic Growth (DAG) medium, and in a variant of DAG supplemented with 200 g/l sucrose (DAG-S). It was found that both aerobes and anaerobes were suppressed by the additional sucrose. In a clinical trial 1,800 blood cultures froms 1,332 patients were simultaneously inoculated into DAG and DAG-S. Results showed that excess sucrose did not improve the yield of anaerobic or aerobic microorganisms and rather tended to inhibit their growth. The only microorganisms which possibly benefitted from DAG-S were some Enterobacteriaceae species.

Bacteria↗