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F Crokaert

Publications and source records attributed to F Crokaert.

At least 55 records · Page 3Linked to original sources
PubMed1987

Detection of Gardnerella vaginalis in vaginal specimens by direct immunofluorescence.

The preparation of a fluorescein-labeled Gardnerella vaginalis polyclonal antibody is described, and its usefulness is assessed for the detection of this microorganism in vaginal samples obtained from 263 women attending the gynecological department of a general hospital, 66 of whom harbored an intrauterine device. The direct immunofluorescence technique was positive for G. vaginalis in 21% of the specimens, whereas only 12.5% of the total bacteriological cultures were positive. The frequency was higher in patients harboring intrauterine devices since 34.8% exhibited positive immunofluorescence and 30.3% exhibited positive cultures.

Animals↗
PubMed1987

[Measure by turbidimetry and bactericidal effect of the speed of action of clavulanic acid, amoxicillin and their combinations on a Haemophilus influenzae producer of beta-lactamase].

The amoxicillin-acid clavulanic acid combination is known to be active on H. influenzae beta-lactamase producer. Clavulanic acid possesses its own antibacterial activity at high concentrations. As the combination of two beta-lactams is sometimes antagonist, we studied the action of amoxicillin, clavulanic acid alone and in combination on H. influenzae beta-lactamase producer by kinetic turbidimetry and time-kill curve. Clavulanic acid alone has slowed down the growth at 8 micrograms/ml, has inhibited at 32 micrograms/ml and was bactericidal at 128 micrograms/ml. The amoxicillin-clavulanic acid combination (proportion 4/1) was bactericidal at 2-0.5 micrograms/ml. The speed of bactericidal activity was only slightly dependent on concentrations. The increase in biomass measured by turbidimetry has been important. As for all beta-lactams it was due to the formation of spheroplasts, non viable after 24 h.

Amoxicillin↗
PubMed1986

In-vitro activity of pefloxacin compared to other antibiotics.

Pefloxacin is a new quinolone carboxylic acid with a broad spectrum of antibacterial activity. A comparison was made of the in-vitro activity of pefloxacin and that of nine other antibiotics (ampicillin, ticarcillin, piperacillin, cefazolin, cefotaxime, ceftazidime, gentamicin, amikacin and norfloxacin). The MIC90 of pefloxacin against 500 strains of Enterobacteriaceae ranged from 0.25 mg/l (Escherichia coli, indole + Proteus spp., Enterobacter cloacae, Salmonella spp. and Shigella spp.) to 1 mg/l (Klebsiella pneumoniae). Pefloxacin inhibited 90% of 52 strains of Pseudomonas aeruginosa at 2.5 mg/l (range 0.25 mg/l-4 mg/l). The MIC90 of pefloxacin against 100 Staphylococcus aureus strains (78 oxacillin resistant strains) was 0.4 mg/l (range 0.12-0.5 mg/l). It was markedly less active against Streptococcus faecalis and Str. pneumoniae (37 strains of each species) the MIC90 being 4 mg/l against both species. Overall, pefloxacin was at least as active as the third-generation cephalosporins against Enterobacteriaceae and was more active than any other antibiotic tested against P. aeruginosa, S. epidermidis, and S. aureus. Against E. coli, pefloxacin had a more rapid anti-bacterial activity than piperacillin. A paradoxical effect was observed with pefloxacin. An optimal killing rate was observed at concentrations of pefloxacin compatible with those one can expect in blood of patients treated with this drug.

Anti-Bacterial Agents↗
PubMed1986

Effect on growth curves and killing curves of brief exposure of Escherichia coli to imipenem and piperacillin.

Escherichia coli was exposed to various concentrations of imipenem and piperacillin. As with the majority of beta-lactam antibiotics, the kinetic turbidometric growth curves showed, during the first few hours, an increase in optical density (OD) before lysis. This increase in OD depended on the concentration of imipenem and was independent of the concentration of piperacillin. A good correlation was found between the pre-lytic increase in OD and the killing curve. The bactericidal activity rate of imipenem was concentration-dependent. Imipenem was rapidly bactericidal, in contrast to piperacillin.

Bacterial Proteins↗
PubMed1986

Clinical evaluation of teicoplanin for therapy of severe infections caused by gram-positive bacteria.

Teicoplanin was evaluated in 47 patients with severe infections, including 14 patients with bone infections, 11 patients with soft-tissue infections, 7 patients with endocarditis, 5 patients with pneumonia, 3 patients with septic thrombophlebitis, 3 patients with septicemia of unknown origin, and 4 patients with miscellaneous infections. Overall, bacteremia was documented in 24 patients. The pathogens isolated were 35 strains of Staphylococcus aureus (including 8 methicillin-resistant strains), 4 strains of Staphylococcus epidermidis, 4 strains of Streptococcus faecalis, 2 strains of Streptococcus pneumoniae, 5 strains of other streptococci, and 1 Micrococcus luteus strain. A total of 22 patients (46.8%) were clinically cured, 8 patients (17.0%) improved, 2 patients (4.3%) had relapses after initial improvement, and 15 patients (31.9%) failed to respond. The results were better in nonbacteremic patients (19 of 23 patients [82.6%] were cured or improved) than in patients with bacteremia (12 of 24 patients [50%] were cured or improved). Bacteriological cure occurred in 25 patients (53.2%), and superinfections were documented in 6 patients (12.8%). No major adverse effects were observed. We conclude that teicoplanin is a potentially effective and well-tolerated antimicrobial agent for therapy of nonbacteremic infections caused by gram-positive bacteria.

Adult↗
PubMed1986

Rate of bactericidal activity for Streptococcus faecalis of a new quinolone, CI-934, compared with that of amoxicillin.

The rate of bactericidal activity of a new quinolone, CI-934, was compared with that of amoxicillin for 20 strains of Streptococcus faecalis. At 10 and 100 micrograms/ml, the bactericidal activity of CI-934 was more rapid at 6 h than that of amoxicillin. A paradoxical effect (a killing rate higher at 1 microgram/ml than at 100 micrograms/ml at 6 h) was observed for 19 of the 20 strains with amoxicillin and for 1 of the 20 strains with CI-934. It remains to be demonstrated whether in vivo studies will confirm the results obtained in vitro.

Amoxicillin↗
PubMed1986

Effect of mecillinam on Escherichia coli growth curves when given alone and associated with ampicillin.

The effects on growth curves of strains of Escherichia coli by mecillinam, ampicillin, and combinations of the two antibiotics were investigated using the Abbott-MS-2 system. Maximal increase in optical density in the residual growth phase was found to be concentration dependent for ampicillin and nearly concentration independent for mecillinam. The addition of ampicillin potentiated the effect on mecillinam. However, when mecillinam concentrations were more than 100 times the MIC or when ampicillin was added with a lag time, the growth curves for combinations of mecillinam plus ampicillin showed a mecillinam profile. Killing curves confirmed that the combination of ampicillin and mecillinam acts strongly synergistic and exerts a much faster bactericidal effect.

Amdinocillin↗
PubMed1986

[Growth curves and killing rate of Haemophilus influenzae exposed to amoxicillin, cefaclor and cefotaxime].

The antibacterial activity of beta-lactams against H. influenzae is difficult to evaluate as a result of the osmotic-pressure-dependent formation of filaments and spheroplasts whose viability is still under debate. We compared growth curves obtained by optic density measurements and by UFC/ml counts for H. influenzae in the presence of amoxicillin, cefaclor and cefotaxime in various concentrations. Only the early response to antibiotics, observed during the first six hours of antibiotic-culture contact, was considered. Results showed, for each of the three antibiotics: an increase in optic density with formation of abnormal organisms that correlated poorly with antibiotic concentrations; a stable number of UFC/ml for more than 90 mn, followed by a slow fall reaching at the most 1.5 Log 10 UFC/ml at the sixth hour. We conclude that amoxicillin, cefaclor and cefotaxime in active concentrations rapidly produce the formation of abnormal organisms with an increase in biomass as a result. These abnormal organisms lose their viability slowly, even with concentrations greater than 50 time the MIC. Cefaclor's MIC and MBC are underestimated when results are read only after 24 hours.

Amoxicillin↗
PubMed1985

Effect on growth curve patterns of brief exposure of bacteria to different concentrations of beta-lactam antibiotics.

The effect of a brief beta-lactam action on a bacterial culture has been studied by combining the use of a high performance photometer with phase contrast microscopic examination. After exposure of the culture with the antibiotic, the growth curves presented in logn OD have shown the importance of the pre-lytic increase in OD (PIOD). Using Escherichia coli a study of the PIOD values allowed us to separate the beta-lactam antibiotics studied into two groups: those whose PIOD were concentration-dependent (ampicillin, carbenicillin, ticarcillin, moxalactam, ceftazidime, cefsulodin, cefotaxime) and those whose PIOD were concentration-independent (or weakly dependent) (azlocillin, mezlocillin, piperacillin). When the PIOD was independent of the concentrations, long filaments were observed by phase contrast microscopy. Using Pseudomonas aeruginosa, all the antibiotics studied produced PIOD values that were barely dependent of the concentrations, and long filaments were observed by phase contrast microscopy. Study of the lag of regrowth in the post antibiotic period using a beta-lactamase technique showed that, if the PIOD was hardly concentration dependent, so was the lag of regrowth.

Ampicillin↗
PubMed1985

Correlation between growth curve and killing curve of Escherichia coli after a brief exposure to suprainhibitory concentrations of ampicillin and piperacillin.

Escherichia coli strains that were susceptible to multiple antibiotics were exposed to suprainhibitory concentrations of ampicillin and piperacillin. As with the majority of beta-lactam antibiotics, the growth curves showed an increase in optical density (OD) before lysis during the first hours. This increase in OD depended on the concentration of ampicillin and was independent of the concentration of piperacillin. A good correlation was found between the prelytic increase in OD and the killing curve. During the prelytic increase in OD, the number of CFU per milliliter remained constant. The decrease in the number of CFU per milliliter depended on the concentration of ampicillin and was independent of the concentration of piperacillin. pH variations gave rise to similar effects on growth curves and killing curves.

Ampicillin↗
PubMed1985

[Comparison of the growth curves of Escherichia coli and Haemophilus influenzae subjected to ampicillin and amoxicillin].

Results of conventional techniques indicate that most non-beta-lactamase producing Haemophilus influenzae strains are "susceptible" to ampicillin and amoxicillin. A previous study of growth curves established using the MS-2 system has demonstrated a faster bacteriolytic activity on Escherichia coli of amoxicillin as compared to ampicillin. A similar study on Haemophilus influenzae ATCC 9795 showed a) significant residual growth subsequent to contact of cultures with antibiotics in concentrations approximating minimal inhibitory concentrations; b) persistent residual growth for all concentrations from 1 to 500 micrograms/ml, with little concentration-dependency. Concentrations of amoxicillin needed to achieve identical inhibition of Haemophilus growth curves were twice those of ampicillin.

Amoxicillin↗
PubMed1984

Isolation of Mobiluncus in four cases of extragenital infections in adult women.

In four adult women with various clinical conditions, curved anaerobic bacilli, similar to organisms recently assigned to the new genus Mobiluncus, were isolated from extragenital sources. None of the patients presented symptoms or clinical abnormalities related to the genital tract. The clinical data of these cases are reported and the microbiological findings are briefly described.

Abscess↗