RESUMO
BACKGROUND: The importance of Mycobacterium tuberculosis strains with disputed rpoB mutations remains to be defined. This study aimed to assess the frequency and types of rpoB mutations in M. tuberculosis isolates from Cubal, Angola, a country with a high incidence of tuberculosis. METHODS: All isolates included (n = 308) were analyzed using phenotypic drug susceptibility testing and GenoType MTBDRplus assay. DNA sequencing of the rpoB gene and determination of rifampicin MIC by macrodilution method were additionally performed on isolates yielding discordant results (n = 12) and those in which the mutation detected was not characterized (n = 8). RESULTS: In total, 85.1% (74/87) of rifampicin-resistant strains had undisputed rpoB mutations -S450L (49), D435V (15), H445D (3), H445Y (2), Q432ins (1), L449M plus S450F (1), S450F (1), S450W (1) and S450Y (1)-; 10.3% (9/87) had disputed rpoB mutations-L430P plus S493L (1), N437del (1), H445L (3), D435Y (2), L452P (2)-, 2.3% (2.3%) showed no rpoB mutations and 2.3% (2/87) showed heteroresistance-D435Y plus L452P and L430P plus S493L-. CONCLUSION: Disputed rpoB mutations were common, occurring in 10.3% of rifampicin resistant isolates. Current phenotyping techniques may be unable to detect this resistance pattern. To increase their sensitivity, a lower concentration of RIF could be used in these tests or alternatively, rpoB mutations could be screened and characterized in all M. tuberculosis strains.
Assuntos
Mycobacterium tuberculosis , Tuberculose , Angola/epidemiologia , Proteínas de Bactérias/genética , RNA Polimerases Dirigidas por DNA/genética , Farmacorresistência Bacteriana/genética , Humanos , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/genética , Tuberculose/epidemiologiaRESUMO
Diagnosis and clinical management of people infected with hepatitis C virus (HCV) relies on results from a combination of serological and virological tests. The aim of this study was to compare the performance of dried plasma spots (DPS), prepared using the cobas® Plasma Separation Card (PSC), to plasma and serum from venipuncture, for HCV diagnosis. We carried out a prospective study using DPS and paired plasma or serum samples. Serum and DPS samples were analyzed by immunoassay using Elecsys® Anti-HCV II (Roche). Plasma and DPS samples were analyzed using the cobas® HCV viral load and cobas® HCV genotyping tests (Roche). All DPS samples that had high anti-HCV antibody titers in serum were also antibody-positive, as were five of eight samples with moderate titers. Eight samples with low titers in serum were negative with DPS. Among 80 samples with plasma HCV viral loads between 61.5 and 2.2 × 108 IU/mL, 74 were RNA-positive in DPS. The mean viral load difference between plasma and DPS was 2.65 log10 IU/mL. The performance of DPS for detection of serological and virological markers of hepatitis C virus infection was comparable to that of the conventional specimen types. However, the limits of detection were higher for DPS.
Assuntos
Influenza Humana/epidemiologia , Pandemias , Animais , Aves , China/epidemiologia , Europa (Continente)/epidemiologia , Variação Genética , Humanos , Incidência , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Vacinas contra Influenza , Influenza Aviária/virologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Estações do AnoRESUMO
BACKGROUND: To determine the prevalence of Chlamydia trachomatis infection in our area by molecular methods. METHODS: We describe the combined results of three studies carried out in the city of Barcelona including a total of 408 women considered to be at high risk for acquiring a sexually transmitted disease (STD). The first study was performed in 94 women attended at a public STD clinic located downtown, the second in 112 women attended at the Hospital Clinic and the third in 202 women attended at Hospital Vall d'Hebron (both third-level hospitals). In the first and third study endocervical exudate was tested with a PCR technique, and in the second study LCR was performed in 20-ml urine samples. RESULTS: Chlamydia trachomatis was detected in 1 woman in the first study, in no women in the second and in 3 women in the third. The prevalence of Chlamydia trachomatis infection detected in the three studies using molecular biology techniques was 1.06%, 0% and 1.48% respectively, giving an overall prevalence of 0.98%. CONCLUSION: The prevalence of Chlamydia trachomatis infection in our geographic area is surprisingly low.