[Direct effect of nitroxoline in the inhibition of bacterial adherence to urinary catheters]. / Rôle direct de la nitroxoline dans l'inhibition de l'adhérence bactérienne sur sonde urinaire.

Nitroxolin or 5-nitro-8-hydroxyquinoline, used in the treatment of acute or recurrent uncomplicated urinary tract infection, has been investigated to demonstrate direct inhibitory effect on Escherichia coli adherence to solid surfaces. First of all, influence of growth medium on bacterial adherence was studied. No relation occurs between growth media enhancing production of adhesins and the ability to adhere to solid surfaces. While bacteria are grown on minimal medium, nitroxolin (MIC/16 to MIC/4) can significantly reduce bacterial adherence to urinary catheter of uropathogenic strains of Escherichia coli AL52 and 382. Increasing the concentration of nitroxolin does not proportionally modify this decrease. When growth is realised on LB broth or agar, nitroxolin does not affect bacterial adherence of strain AL52 and higher doses (8 to 32 mg.l-1) are necessary to obtain the same inhibition of adherence of strain 382. Nitroxolin, in certain conditions, can, directly and rapidly, reduce bacterial adherence to solid surfaces.

[Relation of the chelating property of nitroxoline, the surface hydrophobicity and the inhibition of bacterial adherence]. / Relations entre les propriétés de chélation de la nitroxoline, l'hydrophobicite de surface et l'inhibition de l'adhérence bactérienne.

Nitroxoline or 5-nitro-8-hydroxyquinoline acts by a chelating effect with various metallic divalent cations. The chelating property of nitroxoline has been proposed as an hypothesis to explain the activity of this drug, at sub-MIC, on the inhibition of bacterial adherence. Nitroxoline (MIC/4) does not inhibit fimbriae synthesis but its antibacterial activity on E. coli 387 (MS/MS) was decreased by the addition of MgCl2 (50 mM) and CaCl2 (10 mM). The chelating effect of nitroxoline is mainly due to the presence of the nitrous radical in position 5. Nitroxoline would act at the outer membrane level of the bacterial cell-wall by a chelating effect preferentially with Mg++ than Ca++. Furthermore, nitroxoline (MIC/8) increases the bacterial surface hydrophobicity of E. coli 38 in contrast to EDTA (MIC/4). The both products inhibit the bacterial adherence to cells with the same manner.

[Evaluation of the sensitivity of Haemophilus to antibiotics by the modified API-ATB system]. / Evaluation de la sensibilité des haemophilus aux antibiotiques par le système API-ATB modifié.

A simple micromethod in a liquid medium using the API-ATB system was developed for testing the susceptibility of Haemophilus to antibiotics. To evaluate this method, 50 strains, including 12 beta-lactamase producers, were studied. Results were compared to those obtained using MIC determination in a liquid medium (reference) and an agar diffusion method (routine). For all three techniques, a Mueller-Hinton medium enriched in hemoglobin and NAD was used, and cultures were incubated at 37 degrees C for 24 hours in normal atmosphere. Influence of the inoculum on results was evaluated using the API-ATB method for all antibiotics and MIC determination for ampicillin; the optimal inoculum was found to be 8.10(5) CFU/ml. Beta-lactamase was looked for using the chromogen cephalosporin test associated with the API-ATB system. Values of MICs for the various antibiotics were consistent with previous reports. Paired comparison of techniques showed a 5.3% disagreement rate between API-ATB and MIC, with only 0.5% major discrepancies; in contrast, the disagreement rate exceeded 10% when disk diffusion was compared with the two other techniques. We conclude to the reliability and reproducibility of the API-ATB method which seems capable of improving current routine evaluations of the susceptibility of Haemophilus to antibiotics.

[Characterisation of Corynebacterium vaginale by the fluorescent antibody technic (author's transl)]. / Apport de l'immunofluorescence à la caractérisation de Corynebacterium vaginale.

When using the serum of rabbits immunized against the reference vaginal strain 594 of Gardner and Dukes, the authors tried to find an antigenic identity between this strain and the usual strains that can ordinarily be detected in vaginal samples. The immunizing process that has been used is indirect immunofluorescence. Through these studies, it is possible to conclude that, besides usual strains identical to the reference strain, some specific strains can be detected that have the same microscopic and cultural characteristics as Corynebacterium vaginale but that are deprived of its antigenic characteristics.

[Biochemical characterization of Haemophilus strains with a standardized micromethod (author's transl)]. / Détermination des carcatères biochimiques des germes du genre Haemophilus par l'utilisation d'une microméthode normalisée.

Using a standardized micromethod, the authors aimed at the study of biochemical characterization of 51 Haemophilus strains (influenzae and parainfluenzae). The statistical analysis of the results allowed them to definite a theoretical average outline corresponding to three groups of bacteria :-- group of Haemophilus influenzae, -- group of Haemophilus parainfluenzae, -- group of different Haemophilus. The authors propose some modifications in order to make this identification specifically applicable to diagnose species and biotypes of genus Haemophilus.

[Aminopeptidase activity in "Corynebacterium vaginale" (author's transl)]. / Activité aminopeptidaseique de Corynebacterium vaginale.

Aminopeptidase activity can only be detected in significant amounts in Gram-negative bacteria with a test reaction using L-alanine-4-nitro-anilide as substrate. Corynebacterium vaginale show no aminopeptidase activity even after prolonged reaction times. This indicates surely that this microorganism is nt a Gram-negative bacteria.