[1] Univ Zaragoza, Med Prevent & Salud Publ, Dept Microbiol, Zaragoza, Spain
[2] Grp Invest Serv Sanitarios Aragon GRISSA, Santa Eulalia del Campo, Teruel, Spain
[3] Hosp San Jose, Serv Geriatria, Teruel, Spain
[4] Ctr Salud Santa Eulalia Campo, Teruel, Spain