Robert V. Tauxe

Symptoms and risk factors of Helicobacter pylori infection in a cohort of epidemiologists

To identify symptoms and risk factors associated with Helicobacter pylori infection, a cohort of 341 epidemiologists was studied. All subjects had one banked serum (collected between 1969 and 1987) and one recent serum sample (collected in 1988) evaluated for H. pylori immunoglobulin G by enzyme-linked immunosorbent assay; subjects provided information on gastrointestinal symptoms and risk factors for gastritis and peptic ulcer disease. Prevalence of infection decreased from the early 1970s to the present. Eleven subjects (3% of the total cohort) seroconverted during the interval between serum samples, giving a crude conversion rate of 0.49% per person-year (95% confidence interval, 0.3-0.9). Nonreactors on the 1988 serum sample described similar symptoms to reactors. However, subjects who seroconverted in the interval between the two serum samples were more likely than either persistent nonreactors [relative risk (RR), 4.1] or persistent reactors (RR, 3.7) to have experienced upper gastrointestinal symptoms in the interval years. Consumption of caffeinated beverages (RR, 4.6) and residence in the northeastern United States (RR, 5.3) seemed to increase risk for infection. Because pain was similarly common in H. pylori-positive and -negative patients, H. pylori cannot be summarily accepted as the cause of dyspeptic symptoms even when infection is confirmed.

Hemolytic-uremic syndrome during an outbreak of Escherichia coli O157:H7 infections in institutions for mentally retarded persons: Clinical and epidemiologic observations

PURPOSE To describe an outbreak of Escherichia coli O175:H7 infection resulting in a high rate of progression to hemolytic-uremic syndrome, and to attempt to identify predictors of and risk factors for progression. DESIGN Case-control study among employees and comparison of daily clinical features in two groups: infected residents with subsequent development of HUS and those who had no complications. SETTING Two institutions for retarded persons in Utah. PATIENTS Twenty residents with E. coli O157:H7 infection (13 culture confirmed, 2 probable, and 5 possible); HUS developed in 8, and 4 died. Thirty-one infected employees (3 with culture-confirmed, 6 with probable, and 22 with possible infection). MEASUREMENTS AND MAIN RESULTS In a case-control study among employees, infection was independently associated with eating ground beef from a single lot prepared at several barbecues and with close contact with a resident who had diarrhea. Five of eight residents in whom HUS developed had received trimethoprim-sulfamethoxazole, compared with none of seven who had no subsequent complications (p = 0.026); this finding may reflect antimicrobial treatment of patients with more severe illness. Compared with infected residents without complications, persons with HUS were younger (median age 13 vs 27 years, p = 0.043) and, by the third day of illness, had higher leukocyte counts (median 23.7 X 10(9)/L vs 9.1 X 10(9)/L, p = 0.018) and temperature (median 38.5 degrees C vs 37.0 degrees C, p = 0.016). Leukocytosis peaked on day 4, more than 24 hours before signs of HUS appeared. CONCLUSIONS Food-borne outbreaks of E. coli O157:H7 in institutions may have devastating effects. Leukocytosis and fever may precede and predict HUS in patients with E. coli O157:H7 infection.