Comparison of two assay methods for patterns of adherence to HEp-2 cells of Escherichia coli from patients with diarrhea.

To determine whether methodological differences in the HEp-2 adherence assay could explain conflicting results of field studies, 244 strains of Escherichia coli from Mexican children with diarrhea were tested for patterns of adherence by the method used at the Center for Vaccine Development, University of Maryland (CVD), and at the Center for Infectious Diseases, University of Texas Medical School and School of Public Health (UTH). The CVD assay differentiated three phenotypes of adherent E. coli, including localized, diffuse, or aggregative adherence (LA, DA, or AA, respectively).

Detection of staphylococcal enterotoxin B. A comparative study of ELISA and ELIFA systems.

The enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunofiltration assay (ELIFA) sandwich methods have been compared for their ability to detect staphylococcal enterotoxin B (SEB) in biological samples. Using the avidin-biotin amplification system in the ELISA, high sensitivity was observed and staphylococcal protein A interference was completely prevented. In contrast, ELIFA was less sensitive than ELISA, but very easy to perform, fast and simple to read routinely.

Emergence of resistant fecal Escherichia coli in travelers not taking prophylactic antimicrobial agents.

Fecal specimens from individuals traveling to Mexico were examined before, during, and after travel for the presence of Escherichia coli resistant to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, sulfonamides, trimethoprim (TMP), and TMP-sulfamethoxazole (TMP-SMX). None of these individuals took prophylactic antibiotics, although 4 of 13 took short courses of an antimicrobial agent for therapy of traveler's diarrhea. With an average of 9.

Treatment of traveler's diarrhea with sulfamethoxazole and trimethoprim and loperamide.

In a randomized, double-blind, placebo-controlled trial, 227 US adults with acute diarrhea in Mexico received a single dose of sulfamethoxazole and trimethoprim (1600/320 mg) or 3 days of therapy with loperamide hydrochloride (4-mg loading dose, then 2 mg orally after each loose stool), sulfamethoxazole-trimethoprim (800/160 mg orally twice daily), or the combination of both. Subjects treated with the combination had the shortest average duration of diarrhea compared with the placebo group (1 hour vs 59 hours), took the least amount of loperamide after the loading dose (3.8 mg), and had the shortest duration of diarrhea associated with fecal leukocytes or blood-tinged stools (4.

Use of bismuth subsalicylate for the prevention of travelers' diarrhea.

During the months of July 1977 and July 1985, students from the United States participated in a double-blind, placebo-controlled trial examining the effectiveness of liquid bismuth subsalicylate (BSS) (1977) and two dosages of the tablet formulation of BSS (1985) in preventing diarrhea while in Guadalajara, Mexico. In the first study, 62 subjects received BSS for 3 weeks at a dosage of 60 mL four times daily (4.2 g of BSS/d) compared with 66 students receiving an oral placebo at a similar dosage schedule.

Multiple-challenge study of host susceptibility to Norwalk gastroenteritis in US adults.

In a multiple-challenge study of US adult volunteers with low or high levels of serum antibody to Norwalk virus, Norwalk inoculum 8FIIa was administered to 42 subjects, 22 were challenged 6 months later, and 19 received a third challenge after 6 more months. All 12 with high (greater than or equal to 1:200) but only 19 of 30 with low (less than 1:100) prechallenge titers experienced illness or a fourfold increase in titer after the first challenge (P less than .025).

Rapid detection of proteins by enzyme-linked immunofiltration assay after transfer onto nitrocellulose membranes.

Enzyme-linked immunofiltration assay (ELIFA) for labeling transferred proteins is an interesting and powerful technique for the rapid specific detection (15 min) of proteins immobilized on nitrocellulose or nylon membranes (0.20 and 0.45 micron).

An observational study of naturally acquired immunity to rotaviral diarrhea in a cohort of 363 Egyptian children. Calculation of risk for second episodes using age-specific person-years of observation.

A cohort of 363 rural children in Bilbeis, Egypt, were followed from birth from 1981 to 1983, with twice-weekly home visits made to detect diarrheal illness. Enzyme-linked immunosorbent assay was used for detection of rotavirus in stools collected during episodes of diarrhea. Rotavirus-associated diarrhea was detected once in 74 children and twice in 12 children.

Evaluation of assay systems for the detection of rotavirus in stool specimens.

We tested 41 rotavirus positive and 42 negative specimens as determined by electron microscopy. The assays systems used were an indirect NIH-ELISA, Meritec-Rotavirus, Virogen Rotatest, and Rotazyme II. Meritec and Virogen (latex agglutination assays) were the most sensitive tests, detecting 95% of the positive specimens.

Hormonal influences on the middle-affinity estrogen-binding sites in the liver of the newt Pleurodeles waltl.

The effects of hormonal changes on the male-specific, middle-affinity, estrogen-binding component (MEBC) were investigated in the Pleurodele. Induction of MEBC was shown to be under androgen control, similar to that observed for the cytoplasmic middle-affinity estrogen-binding sites in rat liver and human hepatoma cells. But, in contrast to the male-specific middle-affinity estrogen-binding sites identified in the rat, the administration of estrogen to male Pleurodeles did not lead to the disappearance of MEBC but raised levels significantly.

A comparative study of furazolidone and placebo in addition to oral rehydration in the treatment of acute infantile diarrhea.

Between July and October 1987 an outpatient study of 191 children with acute diarrhea was undertaken in two rural communities in Mexico. Through a double-blind randomization we compared the efficacy of a combination therapy of furazolidone, 7.5 mg/kg/day, plus standard oral rehydration therapy (ORT) (96 patients) versus a placebo plus ORT (95 patients), each given for 5 days.

A cost-effectiveness comparison of the use of antimicrobial agents for treatment or prophylaxis of travelers' diarrhea.

We conducted a decision analysis to compare the cost-effectiveness of antimicrobial agents used for treatment with their use for prophylaxis of travelers' diarrhea. Estimates of the likelihood and the cost of various outcomes were obtained from a panel of experts using the Delphi group opinion technique. Treatment with sulfamethoxazole-trimethoprim for three days was compared with daily prophylaxis with sulfamethoxazole-trimethoprim or doxycycline.

Heat susceptibility of bacterial enteropathogens. Implications for the prevention of travelers' diarrhea.

The heat susceptibility of four bacterial enteropathogens in foods and water was studied to develop effective recommendations for travelers to regions where diarrheal diseases are important health problems. All enteropathogens tested survived well in foods stored at refrigerator temperature (4 degrees C), room temperature (25 degrees C), and 50 degrees C, which is too hot to touch. Tap water had to be heated above 65 degrees C to reliably kill all bacterial enteropathogens.

Shigella.

Shigella strains capable of producing illness possess a 140 megadalton plasmid that determines its property of epithelial cell penetration. In the classic presentation, there is a descending intestinal tract infection beginning with the passage of small numbers of large-volume stools and progressing to the passage of many small-volume stools that contain blood and mucus. Shigellae are efficiently transmitted to contacts in person-to-person spread and only 200 viable cells are sufficient to produce illness in susceptible persons.

Enzyme immunoassay for the detection of Giardia lamblia.

An enzyme immunoassay (EIA) was developed for direct detection of Giardia lamblia antigens in fecal specimens. The EIA was evaluated by testing specimens from 1,331 subjects in the USA and Egypt. For the 353 specimens from human subjects in the USA there was a 97% overall agreement between the results of the EIA and direct microscopic examination, yielding a sensitivity and specificity of 92% and 99% respectively.

Seroepidemiology of cholera in Gulf coastal Texas.

Single serum samples from 559 volunteers from a Texas Gulf Coast area were examined for vibriocidal antibody to Vibrio cholerae O1 (biotype El Tor, serotype Inaba) by a microtiter method. Elevated levels of vibriocidal antibody were present in 14% of the subjects. Also, 6.

Illness and reservoirs associated with Giardia lamblia infection in rural Egypt: the case against treatment in developing world environments of high endemicity.

A longitudinal investigation of the health effects and reservoirs of Giardia was undertaken during 1984-1985 in 40 households located in the rural Nile Delta region of Egypt. Stool specimens obtained once weekly for six months from 2-4-year-old children were cyst- or trophozoite-positive in 42% of the 724 examined. Only one child remained Giardia-negative during the study.

Test-of-cure stool cultures for traveler's diarrhea.

Whether enteropathogens were eradicated or persisted in test-of-cure stool cultures from 251 patients with traveler's diarrhea, the durations of diarrhea were similar within the antimicrobial agent-treated (32 versus 33 h) and placebo-treated (82 versus 96 h) groups. Routine test-of-cure stool cultures can be useful for evaluating treatment failures and for assessing asymptomatic carriage of enteropathogens after treatment, but they are not mandated in the design of placebo-controlled antimicrobial treatment trials in traveler's diarrhea when the focus of the trial is clinical efficacy.