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Biomedical subjects

F Crokaert

Publications and source records attributed to F Crokaert.

At least 73 records · Page 4Linked to original sources
PubMed1984

[Relation between PBPs (penicillin-binding proteins) and growth curves of Escherichia coli submitted to ampicillin and oxacillin].

Growth curves recorded by the MS-2 (high performance photometer) provide a new means for studying PBPs. Indeed, the increase in prelytic OD (observed during the first two hours of contact between beta- lactams and cultures) is concentration- independent for antibiotics bound to PBPs3 ( Yourassowsky et al., 1981). Oxacillin has high affinity for PBP3 of E. coli (Curtis et al., 1979). Growth curves confirm biochemical studies: prelytic increase of OD of E. coli cultures is concentration- independent for oxacillin (100-2000 micrograms/ml), conversely to results observed with ampicillin and amoxycillin.

Ampicillin↗
PubMed1983

Growth curve patterns and regrowth in post antibiotic period of Escherichia coli exposed to ampicillin and amoxycillin.

The growth curve patterns of 8 strains of Escherichia coli exposed to amoxycillin or ampicillin were studied in the MS-2 system, which allows an accurate comparison over a wide range of concentrations. The early response (the first 2 h) of the growth curve showed residual growth (increase in OD before lysis) after the introduction of the antibiotics. The maximal value of this residual growth (MRVG) was measured for ampicillin and amoxycillin concentrations from 1 to 500 mg/l. The rate of regrowth in the post antibiotic period was studied by the use of beta-lactamase to eliminate the penicillins. In these experimental conditions the following observations were made: (a) the MVRG dropped more rapidly in amoxycillin-treated than in ampicillin-treated cultures. This effect was observed at concentrations from twice the MIC to 500 mg/l, despite the fact that some strains have a lower susceptibility to amoxycillin in terms of MIC values. (b) neutralization of antibiotic by beta-lactamase caused a longer lag of regrowth in amoxycillin-treated cultures than in ampicillin-exposed cultures.

Amoxicillin↗
PubMed1983

International collaborative study on standardization of bacterial sensitivity to fosfomycin.

An international collaborative study was undertaken involving 6 working groups to correlate the zone sizes obtained with 50 micrograms fosfomycin + 25 micrograms glucose-6-micrograms glucose-6-phosphate (G6P) and 50 micrograms fosfomycin + 50 micrograms G6P/disc with the MICs in the presence of 25 mg G6P/litre. The recommendations of the ICS for the MIC and disc diffusion methods were followed and Oxoid Mueller-Hinton agar was used. The regression lines obtained with the method of least squares show that the best correlation coefficient (r = 0.8227) corresponds to the disc with 50 micrograms fosfomycin + 50 micrograms G6P. Considering both the pharmacokinetics of fosfomycin after intravenous administration of 2 or 4 g and the distribution of sensitive bacterial populations, two breakpoints were established at MIC values of 16 and 64 mg/l corresponding to zone sizes and 18 and 22 mm, respectively.

Anti-Bacterial Agents↗
PubMed1983

[Growth curves of Escherichia coli submitted to fosfomycin].

In the presence of glucose-6-phosphate, the growth curves of Escherichia coli submitted to several concentrations of fosfomycin show: a) a delay of growth of the bacteria at concentrations 16 to 32 times lower than the minimum inhibitory concentration, b) the presence of resistant bacteria in regrowing cultures under subinhibitory concentrations.

Anti-Bacterial Agents↗
PubMed1982

Gallium-67 citrate as an aid to the diagnosis of infection in hip surgery.

We have evaluated the use of Gallium-67 scans as an aid to the diagnosis of infection around the hip joint after operation. We performed 12 gallium-67 scintiscans on six patients with diaphyseal fractures of the femur or tibia reduced by external fixation, and 65 scintiscans on 60 hips after operation, which included 22 Moore's prosthesis, 31 total replacements, three nail-plates and four revisions of total replacements. We also scanned the healing surgical wounds in a further 11 patients. Simple fractures or osteotomies did not lead to abnormal uptake of 67Ga. Although some uptake in the scar was encountered the surgical wound did not complicate the interpretation of the scan. When assessing infection in the hip operations the rate of true-positive was 11/11, or 100%. The false-positive rate could not be assessed until after at least one year's follow-up. It was certainly less than 14% immediately after operation and less than 6% when the scan was performed three months after operation. Four patients were found to have a loose prosthesis but had a normal scintiscan, as had three patients presenting with post-operative pain. It appears that 67Ga is clinically an efficient means for early detection of infection about the operated hip, and is useful in the differential diagnosis of a painful hip after surgery.

Adult↗
PubMed1982

Activities of amoxicillin and clavulanic acid combinations against urinary tract infections.

Urinary tract infection caused by beta-lactamase-producing bacteria were treated with 500 mg of amoxicillin three times daily plus either 250 or 125 mg of clavulanic acid three times daily. The overall cure rate was 63.6%, 77.7% with the high dose of clavulanic acid and 53.8% with the low dose. Gastrointestinal intolerance was common in the high-dose clavulanic acid regimen.

Administration, Oral↗
PubMed1982

[Regrowth in post-antibiotic period. A new approach based on the early response of the growth curve (author's transl)].

Growth curve studies (MS-2 Abbott) of Escherichia coli and Pseudomonas aeruginosa cultures submitted to different beta-lactams concentrations showed that a) the maximal values of residual growth (MVRG) observed in the first hours of contact between antibiotic and bacteria was either concentration dependent (carbenicillin, ticarcillin, moxalactam, ceftazidime, cefsulodin against Escherichia coli) or concentration independent (azlocillin, mezlocillin, piperacillin against E. coli and all beta-lactams against P. aeruginosa) ; b) a relationship was found between MVRG and lag of regrowth in the postantibiotic period ; c) the MVRG independent of antibiotic concentration was associated with filament formation. This observation may contribute to athe best choice of the mode of administration of an antibiotic in therapeutic field (peak level or plateau).

Anti-Bacterial Agents↗