[Virulence factor of Escherichia coli strains isolated during asymptomatic bacteriura among patients treated by drugs with acetylcholine antagonistic activity in a psychiatric institute]. / Infections urinaires par Escherichia coli sous anticholinergiques.

In two successive investigations on nosocomial infections in our hospital, wa have found that asymptomatic bacteriuria is closely related to age (over 50 years) and to treatment with acetylcholine antagonistic activity. We therefore searched for the presence and expression of genes coding for the virulence factors usually present in uropathogenic E. coli in our strains, in strains isolated during asymptomatic bacteriura related to neurologic bladder, and in strains isolated during symptomatic bacteriura. We found that strains from neurologic bladders rarely carried one or two virulence factors while 50% of our strains isolated from asymptomatic bacteriuria carriea at least 3 virulence factors commonly found in strains isolated from symptomatic urinary tract infection. Consequently, it appears important to look for urinary tract infection in patients (over 50 years of age) treated with such drugs, and to look for virulence factors in case of asymptomatic bacteriura. If the stains carry no virulence factors, no antibiotic treatment shoud be instituted but the patients should be invited to drink more water than usual in order to promote elimination of the strains in the urine. Inversely, if the strains carry virulence factors, an adpted antibiotic treatment should be started.

[Detection of trypanosomes in blood by the Quantitative Buffy Coat (QBC) technique: experimental evaluation]. / Détection des trypanosomes dans le sang par la technique du Quantitative Buffy Coat (QBC): évaluation expérimentale.

Microhematocrit centrifugation (Woo test) and miniature anion exchange are the most widely used techniques for routine detection of Trypanosoma brucei gambiense in endemic areas. The QBC technique developed for diagnosis of malaria has been successfully used for detection of trypanosoma in blood. The purpose of this laboratory study was to evaluate the end-point sensitivity of the QBC test in comparison with the Woo test. Decreasing concentrations from 15 x 10(5) to 15 trypanosomes/ml of human blood were tested using the two techniques. Sensitivity was calculated in function of reading time at each concentration. Results showed that the sensitivity of the QBC test was 95% down to a concentration of 450 trypanosomes/ml. In comparison 95% sensitivity of the Woo test was observed only down to 7500 trypanosomes/ml and reading time was twofold longer. These findings were reproducible for two hours after sample preparation but deterioration was rapid thereafter. Given its simplicity and sensitivity, QBC test would appear to be a suitable technique for in-field screening programs for human African trypanosomiasis.