Seroprevalence of Toxocara infection in children from southern Brazil.

The seroprevalence of Toxocara canis antibodies in children aged from 1 to 12 yr old was evaluated in Pelotas City, Rio Grande do Sul, Brazil. Human toxocariasis or visceral larva migrans (VLM) was diagnosed with the use of an ELISA based on the T. canis excretory-secretory (TES) antigens; Western blotting was used to confirm the ELISA-positive results. From 427 samples, 50.6% were positive for the presence of anti-TES antibodies. A confirmatory test (Western blot) was carried out on a sample of the ELISA-positive sera (n = 70), and all were positive. The Western blots had specific banding pattern characteristics, where the 30-kDa fraction demonstrated the highest reactivity. This fraction could be important for the specific diagnosis of toxocariasis.

Activity of ß-lapachone derivatives against rifampicin-susceptible and -resistant strains of Mycobacterium tuberculosis.

The increase of incidence of tuberculosis (TB) with resistant strains and HIV co-infection has reinforced the necessity of developing new drugs for its treatment. The reaction of naphthoquinones with aromatic or aliphatic aldehydes in the presence of ammonium acetate led to the synthesis of the three ß-lapachone derivatives (naphthoimidazoles) that were tested in this study. Phenazines were prepared by the reaction of the respective naphtoquinone with o-phenylenediamine in acetic acid under reflux. The antimicrobial activity of the derivatives was evaluated in vitro against Mycobacterium tuberculosis H37Rv (ATCC 27294) and the rifampicin-resistant strain (ATCC 35338) containing a His-526-Tir mutation in the rpoB gene. Using the Resazurin Microtiter Assay (REMA) method, bioactive molecules were observed in the susceptible and resistant strains with MICs ranging from 2.2 µM to 17 µM. The naphthoimidazoles with p-toluyl and indolyl group attached to the imidazole ring were more active against the H37Rv strain (MIC 9.12 µM and 4.2 µM, respectively) than the rifampicin-resistant strain (MIC 8.3 µM and 17 µM, respectively). The phenazine with the allyl-pyran group was most active among the two strains and had an MIC of 2.2 mM. These results show the potential of these molecules as prototypes for future drugs used in treating TB.

Detection of Helicobacter pylori by phenotypic and genotypic methods.

AIMS: This research evaluated the utilization of a urease in-house test, culture and molecular method (ureA PCR) as a diagnostic tool for Helicobacter pylori infection. Furthermore, we assessed the presence of the cagA gene in the specimens and in isolated strains that were positive for ureA by PCR positive. RESULTS: Sensitivity and specificity, respectively, were 100 and 95.8% for the urease in-house test 93.3 and 95.8 for the ureA PCR assay of the specimen and 100 and 100% for the culture. The presence of the cagA gene was observed in eight (53%) ureA-positive samples. CONCLUSIONS: In this study, we found that the PCR technique has applicability in the study of cagA, and other genes related to the H. pylori pathogen. This method can be applied to samples directly from biopsy or isolated from the bacteria.

Comparative evaluation of the Nitrate Reductase Assay and the Resazurin Microtitre Assay for drug susceptibility testing of Mycobacterium tuberculosis against first line anti-tuberculosis drugs

Tuberculosis remains as a serious infection disease of worldwide distribution, with high morbidity and mortality, mainly in low socio-economic condition countries. The state of emergency of tuberculosis caused by the resistant and multidrug-resistant (MDR) strains, became the main threat to the tuberculosis treatment and control programs. A fast detection method for the resistant strains will allow the implementation of an adequate treatment and contribute for controlling the dissemination of these resistant strains. This study evaluated the performance of the nitrate reductase assay in solid (NRA-LJ) and liquid (NRA-7H9) media, to determine the susceptibility to first line anti-tuberculosis drugs: isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and streptomycin (SMR). Both methods NRA-LJ and NRA-7H9 were evaluated among 18 strains with a known susceptibility profile. The resazurin microtiter assay (REMA) was performed as a reference method. One hundred percent of accordance was observed between NRA-7H9 and REMA for the four tested drugs. When the NRA-LJ method was compared to REMA, the sensitivity and the specificity to INH, RMP, EMB and SMR were 100 percent, 100 percent, 85.7 percent, 76.9 percent and 80 percent, 100 percent, 75 percent and 80 percent, respectively. From the 57 clinical isolates of M. tuberculosis evaluated by NRA-7H9 and REMA, 56 (98.2 percent) were sensitive to all antibiotics tested (INH, RMP, EMB and SMR) by the NRA-7H9 method, while three of these strains were resistant to INH by REMA. One strain showed resistance to INH and RMP for both methods, and MIC of 1.0 µg/ml to INH for both methods, while MIC of 1.0 and 2.0 µg/ml to RMP for REMA and NRA-7H9, respectively. The three assays showed a high level of agreement for rapid detection of rifampicin and isoniazid resistance. Regarding rapidness, the detection of color change in the NRA method is within instants as compared to the overnight incubation required...

A tuberculose permanece como uma séria doença infecciosa, com distribuição mundial, alta morbidade e mortalidade, ocorrendo principalmente em paises com baixa condição econômica. O estado de emergência da tuberculose causada por cepas resistentes e multirresistentes tornou-se uma importante ameaça para o tratamento e programas de controle da tuberculose. Uma rápida detecção de cepas resistentes permitirá a implantação de um tratamento adequado e contribuirá para controlar a disseminação destas cepas. Este estudo avaliou a performace do ensaio nitrato redutase em meio sólido (NRA-LJ) e meio líquido (NRA-7H9), para determinar a sensibilidade frente aos fármacos antituberculosos de primeira linha: isoniazida (INH), rifampicina (RMP), etambutol (EMB) and estreptomicina (SMR). Ambos os métodos, NRA-LJ e NRA-7H9, foram avaliados com 18 cepas com conhecido perfil de sensibilidade. O ensaio de microplaca com resazurina (REMA) foi utilizado como método de referência. A concordância observada entre NRA-7H9 and REMA foi de 100 por cento para os quatro fármacos testados. Quando o método NRA-LJ foi comparado com o REMA, a sensibilidade e especificidade para INH RMP e SMR foram de 100 por cento, 100 por cento, 85,7 por cento, 76,9 por cento e 80 por cento, 100 por cento, 75 por cento and 80 por cento, respectivamente. Dos 57 isolados clinicos de M. tuberculosis avaliados por NRA-7H9 e REMA, 56 (98.2 por cento) foram sensíveis a todos antibióticos testados (INH, RMP, EMB e SMR) pelo método NRA-7H9, enquanto três destas cepas foram resistentes para INH pelo REMA. Uma cepa mostrou resistência para INH e RMP por ambos os métodos, e CMI de 1,0 µg/ml para INH para ambos os métodos, enquanto CMI de 1,0 e 2,0 µg/ml para RMP pelo REMA e NRA-7H9, respectivamente. Os três ensaios mostraram um alto nível ded concordância para uma rápida detecção de resistência a rifampicina e isoniazida. Com relação à rapidez na obtenção dos resultados, a detecção na mudança de...

Comparative evaluation of the Nitrate Reductase Assay and the Resazurin Microtitre Assay for drug susceptibility testing of Mycobacterium tuberculosis against first line anti-tuberculosis drugs.

Tuberculosis remains as a serious infection disease of worldwide distribution, with high morbidity and mortality, mainly in low socio-economic condition countries. The state of emergency of tuberculosis caused by the resistant and multidrug-resistant (MDR) strains, became the main threat to the tuberculosis treatment and control programs. A fast detection method for the resistant strains will allow the implementation of an adequate treatment and contribute for controlling the dissemination of these resistant strains. This study evaluated the performance of the nitrate reductase assay in solid (NRA-LJ) and liquid (NRA-7H9) media, to determine the susceptibility to first line anti-tuberculosis drugs: isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and streptomycin (SMR). Both methods NRA-LJ and NRA-7H9 were evaluated among 18 strains with a known susceptibility profile. The resazurin microtiter assay (REMA) was performed as a reference method. One hundred percent of accordance was observed between NRA-7H9 and REMA for the four tested drugs. When the NRA-LJ method was compared to REMA, the sensitivity and the specificity to INH, RMP, EMB and SMR were 100%, 100 %, 85.7%, 76.9% and 80%, 100%, 75% and 80%, respectively. From the 57 clinical isolates of M. tuberculosis evaluated by NRA-7H9 and REMA, 56 (98.2%) were sensitive to all antibiotics tested (INH, RMP, EMB and SMR) by the NRA-7H9 method, while three of these strains were resistant to INH by REMA. One strain showed resistance to INH and RMP for both methods, and MIC of 1.0 µg/ml to INH for both methods, while MIC of 1.0 and 2.0 µg/ml to RMP for REMA and NRA-7H9, respectively. The three assays showed a high level of agreement for rapid detection of rifampicin and isoniazid resistance. Regarding rapidness, the detection of color change in the NRA method is within instants as compared to the overnight incubation required for the REMA test. NRA might represent an inexpensive and alternative assay for rapid detection of resistance in low-income countries.