The susceptibilities to three antimicrobials of 195 Helicobacter pylori strains isolated from Mexican patients is reported; 80% of the strains were resistant to metronidazole, 24% were resistant to clarithromycin, and 18% presented a transient resistance to amoxicillin. Resistance to two or more antimicrobials increased significantly from 1995 to 1997.

Studies examining associations between Helicobacter pylori virulence markers and disease have concentrated on adults in developed countries. This study assessed adults and children in Mexico. Ninety patients were recruited, 56 adults (37 with active peptic ulceration and 19 with no ulcers) and 34 children (all with recurrent abdominal pain and no ulcers). H. pylori was cultured from gastric biopsy specimens, and vacA alleles and cagA were typed by use of polymerase chain reaction from multiple colony sweeps. Multiple vacA types were common in single-biopsy isolates and were more frequent in adults with ulcers (95%) than in adults without ulcers (37%; P<.001) or in children (52%; P<.01). vacA s1b and cagA+ strains were more frequent in adults than in children. vacA s1 and cagA+ strains had similar frequencies in adults with and without ulcers. In conclusion, infection with multiple H. pylori strains, defined by different vacA genotypes, is common in Mexico. Such mixed infection is associated with ulcer disease. Strain populations infecting Mexican adults and children differ.

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In this study, we estimated the prevalence of Helicobacter pylon infection and histologic gastritis in 58 asymptomatic Hispanic adult volunteers (mean age, 41 years; 59% male) by endoscopic biopsy of the upper gastrointestinal tract. Forty-six subjects (79%) were found to harbor H. pylori in gastric biopsies, and all had histologic gastritis. Four other subjects were found to have gastritis in the absence of H. pylori. Similar prevalences of H. pylon and gastritis were noted in all age groups and also in American-born and immigrant Hispanics. Biopsy data and serologic studies of H. pylon antibodies correlated well. We conclude that H. pylon infection is an almost universal finding in the gastric mucosa of asymptomatic adult Hispanics, regardless of age. The clinical significance of these findings is unknown, but we speculate that H. pylon and its associated gastritis could have a role in the high incidence of gastric carcinoma in Hispanic populations.

The aim of this study was to compare the oxidation of L-[1-(13)C]phenylalanine ((13)C-PheOx) in patients with chronic liver failure due to different etiologies using L-[1-(13)C]phenylalanine breath test. Breath samples were collected before the administration of 100 mg L-[1-(13)C]phenylalanine, and every 10 min thereafter until completion of 1 h. Control subjects (n=9) presented a larger cumulative percentage of (13)C dose recovery (CPDR) than patients (n=124) with chronic liver disease, regardless of the etiology (7.5+/-0.7 vs. 4.2+/-0.2, p=0.001). No differences in CPDR were found considering the Child-Pugh (CP) class or etiology: alcoholic (CP A=7.7+/-0.7, CP B=4.1+/-0.5, CP C=2.0+/-0.3), hepatitis C virus (CP A=5.4+/-0.5, CP B=4.0+/-0.2, CP C=2.2+/-0.3), hepatocellular carcinoma (CP A=5.5+/-1.6, CP B=3.6+/-1.8, CP C=2.2+/-1.0); or cryptogenic cirrhotic patients (CP A=7.4+/-1.5, CP B=4.4+/-0.4, CP C=2.1+/-0.7). Results confirm that (13)C-PheOx decreases in patients with cirrhosis with respect to controls, notwithstanding the etiology.

Percentage of (13)C-PheOx obtained by (13)C-PheBT is a strong predictor of survival in patients with chronic liver disease.