Toxocara canis: anthelmintic activity of quinone derivatives in murine toxocarosis.

Human toxocarosis is a chronic tissue parasitosis most often caused by Toxocara canis. The seroprevalence can reach up to 50%, especially among children and adolescents. The anthelmintics used in the treatment have moderate efficacy. The aim of this study was to evaluate the in vitro and in vivo anthelmintic activity of quinones and their derivatives against T. canis larvae and the cytotoxicity of the larvicidal compounds. The compounds were evaluated at 1 mg mL(-1) concentration in microculture plates containing third stage larvae in an Roswell Park Memorial Institute (RPMI) 1640 environment, incubated at 37 °C in 5% CO2 tension for 48 h. Five naphthoxiranes were selected for the cytotoxicity analysis. The cell viability evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays using murine peritoneal macrophages isolated from C57BL/6 mice revealed that the naphthoxiranes (1 and 3) were less cytotoxic at a concentration of 0.05 mg mL(-1). The efficacy of naphthoxiranes (1 and 3) was examined in murine toxocarosis also. The anthelmintic activity was examined by evaluating the number of larvae in the brain, carcass, liver, lungs, heart, kidneys and eyes. Compound (3) demonstrated anthelmintic activity similar to that of albendazole by decreasing the number of larvae in the organs of mice and thus could form the basis of the development of a new anthelmintic drug.

Antimicrobial susceptibility of rapidly growing mycobacteria using the rapid colorimetric method.

Drug susceptibility testing (DST) of rapidly growing mycobacteria (RGM) are recommended for guiding the antimicrobial therapy. We have evaluated the use of resazurin in Mueller-Hinton medium (MHR) for MIC determination of RGM and compared the results with those obtained with the reference standard broth microdilution in Mueller-Hinton (MH) and with the resazurin microtiter assay (REMA) in 7H9 broth. The MIC of eight drugs: amikacin (AMI), cefoxitin (FOX), ciprofloxacin (CIP), clarithromycin (CLA), doxycycline (DOX), linezolid (LZD), moxifloxacin (MXF) and trimethoprim-sulfamethoxazole (TMP-SMX) were evaluated against 76 RGM (18 species) using three methods (MH, MHR, and REMA) in a 96-well plate format incubated at 37 °C over 3-5 days. Results obtained in the MH plates were interpreted by the appearance of turbidity at the bottom of the well before adding the resazurin. MHR and 7H9-REMA plates were read by visual observation for a change in color from blue to pink. The majority of results were obtained at day 5 for MH and 1 day after for MHR and 7H9-REMA. However, the preliminary experiment on time to positivity results using the reference strain showed that the resazurin can be added to the MH at day 2 to produce the results at day 3, but future studies with large sets of strains are required to confirm this suggestion. A high level of agreement (kappa 1.000-0.884) was obtained between the MH and the MHR. Comparison of results obtained with 7H9-REMA, on the other hand, revealed several discrepancies and a lower level of agreement (kappa 1.000-0.111). The majority of the strains were resistant to DOX and TMP-SMX, and the most active antimicrobials for RGM were AMI and FOX. In the present study, MHR represented an excellent alternative for MIC determination of RGM. The results could be read reliably, more easily, and more quickly than with the classical MH method.

The laboratory as a tool to qualify tuberculosis diagnosis.

OBJECTIVES: To evaluate the performance of laboratory diagnosis of tuberculosis, clinical samples underwent culture, species identification and drug susceptibility testing (DST). METHODS: A total of 554 samples from 269 patients were tested for smear microscopy using Kinyoun stain. Culture was performed in Ogawa-Kudoh medium and species identification was performed using the IS6110 amplified region. DST for rifampicin, isoniazid (INH) and streptomycin were carried out using the Resazurin assay. RESULTS: Cultures augmented the number of cases diagnosed by 22.1%, IS6110 amplification identified all Mycobacterium tuberculosis strains thus isolated and DST detected three strains resistant to INH and one multidrug-resistant strain. CONCLUSION: Simultaneous use of different techniques enhanced culture yield, species identification and detection of drug resistance even in a laboratory with limited facilities.