S100A8 and Peptic ulcer: cagA+ strains were found in 74 % of the isolated strains, a frequency similar to that found by Reyes-Leon et al. in 2008 (78.6 %) in strains from pediatric patients with chronic abdominal pain and adults with non-ulcerous dyspepsia or peptic ulcer [43], but higher than that found by Paniagua et al. in 2009 (52.4 %) by multiplex PCR [29].