Biomedical subjects
E Yourassowsky
Publications and source records attributed to E Yourassowsky.
[Haemophilus influenzae-Moraxella lacunata. Isolation of a beta-lactamase-positive dual association].
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Cross-reactivity of environmental bacteria with fluorescent-antibody conjugates for Legionella pneumophila.
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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.
In vitro activity of teicoplanin and vancomycin against anaerobes.
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Is rust a growth promoting factor for Legionella pneumophila?
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Human fascioliasis (distomatosis)
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Infective endocarditis due to Actinobacillus actinomycetemcomitans.
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Flavobacterium multivorum septicemia in a hemodialyzed patient.
A case of Flavobacterium multivorum septicemia in a hemodialyzed patient is reported. Two blood cultures were positive at 48 h, and the patient became afebrile only after antimicrobial therapy. The origin of the septicemia could not be determined.
Detection of beta-glucuronidase in lactose-fermenting members of the family Enterobacteriaceae and its presence in bacterial urine cultures.
Four hundred strains of lactose-fermenting Enterobacteriaceae were tested for hydrolysis of p-nitrophenyl-beta-D-glucopyranosiduronic acid, the chromogenic enzyme substrate of beta-glucuronidase. Escherichia coli was found to be homogeneous with respect to beta-glucuronidase: more than 94% of the examined E. coli strains were positive, whereas none of the other lactose-fermenting strains possessed beta-glucuronidase activity. The qualitative beta-glucuronidase test, as rapid and simple as the o-nitrophenyl-beta-D-galactopyranosidase test, proved to be of diagnostic value, especially in the identification of E. coli in primary urine cultures. No significant differences were observed in the results of experiments in which either substrate-impregnated disks prepared in the laboratory or commercially available tablets were used.
Pseudomonas paucimobilis peritonitis in patients treated by peritoneal dialysis.
Pseudomonas paucimobilis has rarely been reported as an opportunistic human pathogen. We report the isolation of this organism in two patients who developed peritonitis during the course of intermittent or continuous ambulatory peritoneal dialysis. The origin of the infection was related to contamination of the dialysate in the first patient but could not be determined in the second case.
Amikacin concentrations in uninfected postthoracotomy pleural fluid and in serum after intravenous and intrapleural injection.
The pharmacokinetics of amikacin after intravenous (IV) and intrapleural injection was compared in 25 patients with pleural drainage after lung resection. In ten patients 7.5 mg/kg of the drug was injected IV; the mean peak concentrations were 31.2 +/- 2.3 micrograms/ml in the serum and 13.3 +/- 3.8 micrograms/ml in the pleural fluid. The penetration of amikacin in the pleural space was 80 percent. After the intrapleural injection of the same dose of amikacin in 15 patients, the pleural fluid concentrations of the drug were extremely high and well sustained during eight hours; however, serum concentrations reached maximal values of 14.1 +/- 4.7 micrograms/ml, indicating a substantial diffusion of amikacin from the pleural space to the blood. In the case of treatment of pleural infections by local injection of aminoglycosides, the serum concentrations must be kept in mind to avoid systemic intoxication from these drugs.
[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.
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.
Susceptibility of Streptococcus pneumoniae to chloramphenicol and thiamphenicol.
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Late prosthetic valve endocarditis: review of 19 cases and treatment.
Eighteen out of 1606 patients treated by valve replacement between January 1971 to June 1979 were admitted in Brugmann University Hospital for late prosthetic valve endocarditis. Of the 19 episodes (one patient had two distinct episodes four years apart), nine (group I) were treated medically and 10 (group II) by combined medical and surgical therapy. The infective organism was Staphylococcus epidermidis in two-thirds of our cases. Two cases in group I (22.2%) were long-term survivors. In group II, all 10 patients survived reoperation. There were four late deaths; six patients (60%) were still alive 1.8 to 4.4 years later (mean survival three years). Prompt prosthetic valve replacement is recommended in the presence of systemic emboli, evolving murmurs, uncontrolled sepsis or congestive heart failures (especially if the infective organism is a fungus or a staphylococcus), in late prosthetic valve endocarditis.
[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.
[Gas-phase chromatography in the rapid bacteriological diagnosis of infections. Contributions and limitations of this technic].
Gas-liquid chromatography has been used directly on clinical specimens as a method for presumptive diagnosis of anaerobic infections. This technique proved to be valuable and reliable. Combined with a Gram stain, it offers the possibility to differentiate in less than 1 hour aerobic from anaerobic infections by means of detection of volatile fatty acids (short chain monocarboxylic acids) others than acetic acid.