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Background: Although the use of the antimicrobial, trimethoprim-sulfamethoxazole, in combination with the antisecretory and antimotility agent, loperamide, has been shown to be efficacious in the treatment of traveler's diarrhea, the use of fluoroquinolone antimicrobials in combination with loperamide has less support in the literature. The present study was designed to compare the efficacy of ofloxacin versus ofloxacin plus loperamide in the treatment of acute traveler's diarrhea. Method: This prospective, randomized, evaluator-blinded treatment trial was conducted in Guadalajara, Mexico, during the summers of 1992-1994. Adults newly arrived in Mexico from the United States who developed acute diarrhea of less than 2 weeks' duration were randomized to receive orally either: A) ofloxacin, 400 mg once; B) ofloxacin, 200 mg twice a day for six doses; or C) ofloxacin, 400 mg once, plus loperamide, 4 mg once followed by 2 mg after each loose stool, not to exceed 16 mg per day, for 3 days. The duration of illness was the number of hours elapsed from the beginning of therapy to the passage of the last unformed stool. Results: Ofloxacin and loperamide were well tolerated. Combination therapy with single dose ofloxacin plus loperamide was significantly more efficacious in reducing the duration of diarrhea than single dose ofloxacin or ofloxacin given for 3 days (p <.00001). Furthermore, combination therapy was more efficacious when enterotoxigenic Escherichia coli (ETEC) was the pathogen (p <.01) or when no pathogen was isolated (p <.001). Sixty-three percent of subjects passed no further unformed stools after the initial doses of combination therapy, and 91% were well by the end of the first 24 hours. Conclusions: The combined use of a single dose of ofloxacin with loperamide is safe and more efficacious in the treatment of traveler's diarrhea than use of ofloxacin alone.
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Background: Medical charts of subjects treated with placebo from five double-blinded placebo-controlled clinical trials were reviewed to determine pre-enrollment prognostic factors related to later recovery from diarrhea. Method: Recovery or time from initiation of a placebo until passage of the last unformed stool after being declared well was calculated for each subject. Results: A longer duration of diarrhea was associated with presence of fever (rate ratio = 0.34; 95% CI = 0.2-0.9), presence of an invasive pathogen in the stool (rate ratio = 0.35; 95% CI = 0.2-0.7) or a noninvasive pathogen in stool (rate ratio = 0.7; 95% CI = 0.6-1.0), severe abdominal pain or cramps (rate ratio = 0.5; 95% CI = 0.3-0.9), passage of more than five watery stools per 24 hours (rate ratio = 0.58; 95% CI = 0.4-0.8). Severe vomiting predicted a shorter duration of post-enrollment diarrhea (rate ratio = 2.43; 95% CI = 1.1-5.6). Conclusion: A number of clinical and microbiologic factors found in travelers with diarrhea in the present study predicted duration of untreated diarrhea. The authors suggest the use of antimicrobial therapy in travelers with predictors of a long duration of diarrhea. Data developed in the present study may be used to create a historical control for clinical trials of antidiarrheal compounds using the same study criteria.
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Background: Immune protection against cholera infection is probably mediated in part by locally produced, intestinal secretory IgA (sIgA) antibodies. We study the kinetics of intestinal (sIgA) and systemic (serum IgG) antitoxin antibody responses after immunization with whole-cell/recombinant B subunit oral cholera vaccine (WC/rBS) in U.S. travelers to Mexico and Mexican volunteers. Methods: Two doses of WC/rBS were administered 10 days apart to ten U.S. adults, newly arrived in Mexico, and 18 Mexican nationals. Serum IgG and intestinal secretory IgA (sIgA) antibodies to the B subunit of cholera toxin were measured from day 0 to day 21 by a direct enzyme-linked immunosorbent assay (ELISA). Results: Positive serum IgG responses to vaccination were detected in 80% of U.S. adults and in 59% of Mexican adults. All volunteers, regardless of nationality, developed a positive sIgA antibody response to WC/rBS. No differences were observed between U.S. and Mexican volunteers in the magnitude and kinetics of serum IgG responses. We recorded differences in the kinetics of sIgA antibody, with early and late peak sIgA antitoxin responses demonstrated in the Mexican and U.S. volunteer groups, respectively. Although the presence or absence of antitoxin sIgA antibodies prevaccination (sIgA titer > 1:4) did not interfere with the final postimmunization magnitude of the antibody responses (sIgA measurements days 14 and 21), the initial measurement curves showed differences (sIgA measurements days 0 and 3). Conclusions: The WC/rBS vaccine stimulated antitoxin antibody formation both in serum and locally in the intestine. The presence or absence of specific sIgA antibodies prevaccination did not seem to interfere with the magnitude of the antibody responses postvaccination (days 14, 21). The measurement of sIgA responses in fecal extracts appears to provide a simple and sensitive method to assess the intestinal immune response to orally administered vaccines.
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Both the presence of fecal leukocytes and occult blood in stool specimens of travelers with diarrhea have been used as indicators of colonic inflammation due to bacterial infection. This study was conducted to determine if storage temperature of stool specimens can affect the detection of leukocytes and occult blood. Sixteen specimens positive for occult blood and 23 specimens positive for leukocytes were divided into two aliquots. Each aliquot was held at 4 degreesC or 25 degreesC and reexamined daily for fecal leukocytes or occult blood. Four percent of the positive leukocytes specimens and 56% of the occult blood positive specimens were still positive on the fifth day when they were held at 4 degreesC. When the samples were held at 25 degreesC, leukocytes could not be detected after 3 days, but 19% were positive for occult blood on the fifth day. The results indicate that storage temperature of stool specimens was associated with a difference in detection rate.
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The detection and diagnosis of travelers' diarrhea by fecal culture method, often insensitive, expensive, and time consuming, could well be replaced with the latex agglutination test to detect fecal lactoferrin. As an initial screening, this test could be useful to differentiate between those patients who are more likely to have an invasive enteropathogen and those patients requiring antidiarrheal chemotherapy only. Fecal samples from 92 patients with travelers' diarrhea were tested for occult blood, fecal leukocytes, and fecal lactoferrin at stool dilutions of 1:50 and 1:200. The results were compared with findings from fecal cultures for enteropathogens. Statistical analyses were performed measuring the performance of the latex agglutination test for fecal lactoferrin to calculate its sensitivity, specificity, and positive and negative predictive values. Invasive pathogens were identified in 36 (39%), and a noninvasive pathogen was found in 18, or 20%, of the cases. At the stool dilution of 1:50, fecal lactoferrin showed more sensitivity than did leukocytes or occult blood in detecting the presence of invasive enteropathogens and, with a negative predictive value of 94%, was superior in predicting their absence. At the 1:200 dilution, a lower sensitivity of 55%, but a higher specificity of 82%, compared to 55% with the 1:50 dilution, was demonstrated. The determination of fecal lactoferrin might prove to be more useful and less expensive and time consuming as an initial screening for patients presenting with travelers' diarrhea. Further evaluation and antibacterial treatment could, therefore, be reserved for those with a positive lactoferrin test.