ABSTRACT
The impact of hepatitis B virus (HBV) genotypes on the sensitivity of surface antigen (HBsAg) detection assays has been poorly investigated. Here, plasmids carrying consensus or variant coding sequences for HBV surface proteins from genotypes A, D and F, were constructed. HBsAg levels were evaluated in medium and extracts of transfected CHO cells by a commercial polyclonal-based assay. We show that HBsAg detection values of consensus forms from genotypes D and F were, respectively, 37 percent and 30 percent lower than those obtained by genotype A. However, the presence of two single variations, T143M in genotype A, and T125M in genotype D, produced a decrease of 44 percent and an increase of 34 percent, respectively, on HBsAg mean values in comparison with their consensus forms. In conclusion, HBsAg detection levels varied among HBV genotypes. However, unique amino acid substitutions not linked to genotypes, such as T125M and T143M described here, should have more implications in HBV immunological diagnostics than the set of variations characteristic of each HBV genotype.
Subject(s)
Animals , Cricetinae , DNA, Viral/analysis , Hepatitis B Surface Antigens , Hepatitis B virus/genetics , Hepatitis B virus/immunology , Hepatitis B/virology , Amino Acid Sequence , Cricetulus , Enzyme-Linked Immunosorbent Assay , Genotype , Molecular Sequence DataABSTRACT
A total of 74 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from three government hospitals in 2002 and 2003 were examined concerning the distribution of qacA/B gene, which is the determinant of resistance to quaternary ammonium compounds largely employed in hospital disinfection. By polymerase chain reaction the qacA/B gene was found in 80 percent of the isolates, which is a significant result considering it is the first time that qacA/B gene is being reported for Brazilian MRSA strains and it is presented at a high rate.
Subject(s)
Humans , Bacterial Proteins/genetics , Membrane Transport Proteins/genetics , Methicillin Resistance/genetics , Quaternary Ammonium Compounds/pharmacology , Staphylococcus aureus/drug effects , Staphylococcus aureus/genetics , Base Sequence , Polymerase Chain Reaction , Staphylococcus aureus/isolation & purificationABSTRACT
During an epidemiological survey of acute respiratory infection in Rio de Janeiro, among 208 adenovirus isolates, we found two strains that we were not able, by a standard neutralization procedure, to distinguish between type 3 or 7. However, DNA restriction pattern for the two strains with different enzymes were analysed and showed a typical Ad3h profile. Using a cross-neutralization test in which both Ad3p and Ad7p antisera were used in different concentration against 100 TCID 50 of each adenovirus standard and both isolates, we were able to confirm that the two isolates belong to serotype 3. An hemagglutination inhibition test also corroborated the identification of both strains as adenovirus type 3. Comparing Ad3h and Ad3p genome, we observed 16 different restriction enzyme sites, three of which were located in genomic regions encoding polypeptides involved in neutralization sites.
Subject(s)
Humans , Adenoviruses, Human/genetics , Neutralization TestsABSTRACT
Quarenta amostras de Adenovirus tipo 7 foram analisadas por digestao com as enzimas de restricao BamHI, SmaI, EcoRI e HindIII. Estas amostras foram coletadas de pacientes apresentando doenca respiratoria aguda durante os anos de 1980 a 1991. Somente dois tipos genomicos foram encontrados: Ad7b e Ad7e, sendo que Ad7b (87,5 por cento) foi mais frequente que Ad7e (12,5 por cento). O tipo genomico Ad7e apareceu nos anos 1980, 1981 e 1983. Ad7b apareceu durante 1982 e seguiu sendo o unico tipo genomico encontrado de 1984 a 1991. Ambos os tipos genomicos foram responsaveis por infeccoes do trato respiratorio superior (ITRS) e inferior (ITRI), porem a proporcao ITRI/ITRS e mais alta para Ad7b (25/6) que para Ad7e (1/4)