RESUMO
Hepatitis C (HCV)-infected patients are treated with direct-acting antiviral agents (DAAs) in highly effective, well-tolerated, all-oral regimens. However, naturally occurring resistance-associated amino acid substitutions (RASs) may be selected during treatment. This study aimed to screen naturally occurring RASs NS3/NS4A inhibitors (PIs). Samples were obtained from DAA naïve patients, living in São Paulo state, Brazil. Screening for RASs in the HCV NS3 region was conducted in 859 samples from HCV-infected patients, of which 425 and 434 samples were subtype 1a and 1b, respectively. HCV-RNA was extracted, amplified, and sequenced. The overall prevalence of RASs to HCV PIs was 9.4%. The following RASs were observed in HCV-1a subtype infected patients: V36L (2.6%), T54S (1.6%), V55I/A (1.2% / 8.9%, respectively), Q80K (2.1%), R155K (0.5%), and D168E (0.2%); and in HCV-1b infected patients: V36L (0.7%), T54A/S (0.2% and 0.5%, respectively), V55A (0.5%), Q80K (0.2%), D168E (1.6%), and M175L (0.5%). HCV 1a infected subjects had higher serum viral load than that seen in patients infected with HCV 1b. There was no difference between the proportions of NS3 RASs with regards to geographic distribution within the investigated areas. These findings should be supported by additional studies in Brazil to help in the formation of local clinical guidelines for managing hepatitis C.
Assuntos
Antivirais/administração & dosagem , Proteínas de Transporte/antagonistas & inibidores , Farmacorresistência Viral , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Hepatite C/tratamento farmacológico , Inibidores de Proteases/administração & dosagem , Proteínas não Estruturais Virais/antagonistas & inibidores , Adulto , Substituição de Aminoácidos , Brasil/epidemiologia , Proteínas de Transporte/metabolismo , Feminino , Genótipo , Hepacivirus/isolamento & purificação , Hepacivirus/metabolismo , Hepatite C/epidemiologia , Hepatite C/virologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto/efeitos dos fármacos , Prevalência , Proteínas não Estruturais Virais/metabolismo , Adulto JovemRESUMO
This study aimed to investigate the properties of mutations of the active efflux pump genes acrA/B and tolC in Escherichia coli CVCC 1547 when induced by different drugs. The mutations were isolated in vitro by exposing E. coli CVCC 1547 to stepwise increases in the concentration of ceftriaxone (CRO), amikacin (AMK), or ciprofloxacin. The results showed that the minimum inhibitory concentrations for the corresponding drugs increased, as did the minimum inhibitory concentrations for other fluoroquinolones and ß-lactam drugs that were not inducers. DNA sequence analyses of the acrA/B and tolC genes of the mutants and comparison with the parent strain revealed that genetic variations had occurred. Three point mutations resulted in amino acid changes in the proteins expressed. Specifically, strain CRO10 had a mutation in acrA, A309G, that resulted in a Thr-103 to Ala substitution, and a mutation in tolC, G735A, that changed Ala-245 to Thr; strain AMK20 (and AMK30) had a Val-447 to Ile amino acid change in acrB. In addition to the missense mutations in these strains, we detected 7, 20, and 15 nonsense mutations in acrA, acrB, and tolC, respectively. To sum up, multiple genetic sequence variations and some changes in amino acid sequences were detected when E. coli CVCC 1547 was challenged in vitro with CRO, AMK, or ciprofloxacin. These changes may have given rise to multidrug-resistant strains.