[1] Univ Feevale, Inst Hlth Sci, BR-93352000 Novo Hamburgo, RS, Brazil
[2] Univ Fed Rio Grande do Sul, Sch Med, Porto Alegre, RS, Brazil
[3] Univ Austral Chile, Sch Med, Inst Clin Microbiol, Valdivia, Chile
[4] Hosp Clin Porto Alegre, Serv Gastroenterol, Porto Alegre, RS, Brazil
[5] Ctr Univ Metodista, Porto Alegre, RS, Brazil
[6] Univ Fed Rio Grande do Sul, Programa Posgrad Gastroenterol & Hepatol, Porto Alegre, RS, Brazil