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Biomedical subjects

H L Dupont

Publications and source records attributed to H L Dupont.

At least 19 recordsLinked to original sources
PubMed2006

Epidemiology and incidence of Clostridium difficile-associated diarrhoea diagnosed upon admission to a university hospital.

Patients with Clostridium difficile-associated diarrhoea (CDAD) may initially develop symptoms in the community and be subsequently diagnosed at hospital admission. At the present time there is no national surveillance system and no standardized case definition of CDAD in the USA, and baseline data on the incidence and epidemiology of CDAD are scarce. The objective of this study was to report the incidence of CDAD at a tertiary care hospital, and to determine the epidemiology of cases diagnosed within 48h of hospital admission, compared with cases of nosocomial CDAD diagnosed 48h or more after hospitalization. The average incidence was 4.0 cases/10 000 patient-days for CDAD on admission and 7.0 cases/10 000 patient-days for nosocomial CDAD. A significant difference was observed in CDAD rates on admission compared with nosocomial CDAD rates (P=0.017), but no differences were observed over time for either rate. Overall, 44% of cases had CDAD on admission and 56% of cases had nosocomial CDAD. Fifty-six (62%) patients with CDAD on admission had been admitted to the same hospital and 24 (27%) had been admitted to another hospital within the previous 90 days. Only eight (9%) patients had not been exposed to any healthcare services in the 90 days preceding hospital admission. A standardized case definition of healthcare-associated CDAD should include previous hospitalizations. Admitting physicians should consider C. difficile in the differential diagnosis of patients admitted with diarrhoea, with or without a history of admission to healthcare facilities.

Adult↗
PubMed2001

Emergence of trimethoprim-resistant Escherichia coli in healthy persons in the absence of prophylactic or therapeutic antibiotics during travel to Guadalajara, Mexico.

Thirty-nine healthy US students without diarrheal disease and who had not received prophylactic or therapeutic antibiotics were monitored for emergence of trimethoprim-resistant gram-negative fecal flora for a 3-week period after arrival in Guadalajara, Mexico. During this time period, most students showed no change in total fecal gram-negative bacteria (p > 0.05) but showed an increasing level of trimethoprim (TMP) resistance (p < 0.01) among fecal coliforms. Escherichia coli was the TMP-resistant organism isolated in 18 of 39 (46%) healthy students. These 18 TMP-resistant E. coli were also resistant to ampicillin (44%), azithromycin (11%), chloramphenicol (39%), ciprofloxacin (11%), doxycycline (89%), erythromycin (100%), furazolidone (72%), levofloxacin (17%), trimethoprim-sulfamethoxazole (89%) and trovafloxacin (17%). In the absence of prophylactic and therapeutic antibiotics, increased acquisition of TMP-resistant gram-negative fecal flora in this developing country is probably due to poor sanitary conditions and the recurrent and heavy exposure to antimicrobial-resistant indigenous flora as a result of contaminated food and drink.

Adolescent↗
PubMed2000

Markers of enteric inflammation in enteroaggregative Escherichia coli diarrhea in travelers.

As part of a traveler's diarrhea study carried out in Guadalajara, Mexico, and Goa, India, we conducted a case control study to evaluate fecal markers of enteric inflammation in three groups. Forty-five cases of enteroaggregative Escherichia coli (EAEC) diarrhea were compared to 56 controls with enterotoxigenic E. coli (ETEC) diarrhea, and 126 controls with diarrhea without identifiable pathogens. For EAEC cases we found fecal leukocytes, occult blood, and lactoferrin in 13 (28.9%), 14 (31.1%), and 27 (60.0%) patients, respectively; for ETEC controls they were 15 (26.8%), 16 (28.6%), and 15 (26.8%) respectively; and for patients without identifiable pathogens 19 (15.1%), 34 (27.0%) and 27 (21.4%) were seen for the presence of a positive fecal lactoferrin test in EAEC cases was statistically significant compared to both control groups. The study provides evidence that EAEC infection is associated with an intestinal inflammatory response.

Adolescent↗
PubMed1999

Etiology of outpatient pediatric nondysenteric diarrhea: a multicenter study in the United States.

BACKGROUND: Few data have been published recently on the etiology of outpatient pediatric diarrhea in the US. METHODS: We determined the etiology of acute, nondysenteric diarrhea among 147 children between 2 and 11 years old presenting to 9 outpatient clinics in various regions of the US between August, 1991, and August, 1993. Enteropathogens were sought by conventional laboratory methods. The various diarrheagenic Escherichia coli were sought. RESULTS: A recognized etiologic agent was detected in the stools of 89 (60.5%) children and 15 (10) patients had multiple agents detected. Rotavirus was found in 43 (29.3%) of the children, with a spring and winter peak in occurrence. Giardia lamblia was identified in 22 (15%) cases with a spring peak. HEp-2 cell-adherent E. coli were found in 15 (10.2%). Other agents found included: enteric adenovirus in 7 (4.8%); Salmonella in 5 (3.4%); enterohemorrhagic E. coli in 5 (3.4%); enteropathogenic E. coli in 2 (1.4%); enterotoxigenic E. coli in 2 (1.4%); Entamoeba histolytica in 1 (0.70%); and Campylobacter jejuni in 1 (0.7%). CONCLUSIONS: In addition to the presence of conventional enteropathogens, diarrheagenic E. coli (HEp-2 cell-adherent E. coli, enterohemorrhagic E. coli, enteropathogenic E. coli and enterotoxigenic E. coli) were associated with endemic pediatric diarrhea in the US.

Acute Disease↗
PubMed1999

Infectivity of Cryptosporidium parvum in healthy adults with pre-existing anti-C. parvum serum immunoglobulin G.

A 50% infectious dose (ID50) of 132 Cryptosporidium parvum oocysts was previously determined in serologically negative individuals (ELISA). In this study, 17 healthy adults with pre-existing anti-C. parvum serum IgG were challenged with 500-50,000 oocysts. Infection and diarrhea were associated with the higher challenge doses. The ID50 was 1,880 oocysts, > 20-fold higher than in seronegative volunteers. Fecal oocysts were detected in only seven (53.8%) of 13 individuals with clinical cryptosporidiosis, indicating that the host response may effectively decrease the number of oocysts produced. Subjects with the highest absorbances prior to challenge had little to no increase in IgG following challenge, whereas volunteers with lower reactivities showed significant postchallenge increases. This suggests that an upper limit of serum IgG was present in some subjects, while others were further stimulated by an additional exposure. These data indicate that prior exposure to C. parvum provides protection from infection and illness at low oocyst doses.

Adult↗
PubMed1998

Human immunodeficiency virus-associated diarrhea and wasting in Zambia: selected risk factors and clinical associations.

A significant association was observed among human immunodeficiency virus (HIV)-positive adult cases in Lusaka, Zambia compared with HIV-negative controls for chronic diarrhea (68% versus 22%; P < 0.05), weight loss (54% versus 30%; P < 0.05), lymphadenopathy (44% versus 15%; P < 0.05), and skin eruption (33% versus 7%; P < 0.05). Among the HIV-positive children, a higher proportion had clinical evidence of tuberculosis when compared with HIV-negative children (8% versus 1%; P < 0.05). The study demonstrated an association between weight loss in HIV-positive adults and children and chronic diarrhea (odds ratio [OR] = 12.7, 95% confidence interval [CI] = 6.4-25.5; P < 0.001), persistent cough (OR = 7.2, 95% CI = 2.9-14.5; P < 0.001), and an age of 31-45 years (OR = 3.8, 95% CI = 1.8-8.3; P < 0.01). The factors associated with mortality in HIV positive patients included chronic diarrhea (OR = 7.4, 95% CI = 1.6-34; P < 0.01), and lymphadenopathy (OR = 3.89, 95% CI = 1.2-12.2; P < 0.04).

Adolescent↗
PubMed1996

Occult blood versus fecal leukocytes in the diagnosis of bacterial diarrhea: a study of U.S. travelers to Mexico and Mexican children.

A study was done to test the effectiveness of fecal occult blood as a screening test for invasive bacterial pathogens and as a substitute for the fecal leukocyte examination in adult and pediatric cases of acute diarrhea. United States citizens studying in Mexico and Mexican children, both with acute diarrhea had their stools cultured, examined for fecal leukocytes, and tested for occult blood. Using culture results as the criterion standard for detection of bacterial agents, and fecal leukocytes for diarrhea associated with diffuse colonic inflammation, occult blood was tested for its sensitivity, specificity, and predictive value using 2 x 2 tables. Analysis of the data found that occult blood negative samples were reliable indicators of a lack of invasive bacteria in both adult and pediatric patients (negative predictive values of 87% and 96%, respectively). Positive results for either test were not reliably predictive as indicators of invasive bacteria among adults. A positive occult blood test result was significantly more sensitive than a positive fecal leukocyte test result (79% versus 42%) in detecting invasive bacteria in the pediatric patients; however, the positive predictive value was only 24%. The fecal occult blood test is an uncomplicated, low-cost test that was reliable when giving a negative result in detecting a lack of invasive bacteria in adult and pediatric patients with diarrhea. In children, a positive result on a fecal occult blood test is sensitive but not specific in detecting invasive bacterial enteropathogens. These data also indicate that a commercially available test for occult blood represents a suitable alternative to microscopic examination of fecal samples for leukocytes obtained from patients with acute diarrhea.

Acute Disease↗
PubMed1996

Isolation of Campylobacter species from Zambian patients with acute diarrhoea.

Four hundred and one consecutive diarrhoea patients and 101 adult patients without diarrhoea were enrolled for this study from a health centre in Lusaka. Campylobacter was isolated from 6% of patients with acute diarrhoea. However, non of these were seen in control group. Further studies are being carried out to determine the importance of Campylobacter species with other bacterial pathogens. It will also be interesting to see its impact and association with human immuno deficiency virus in this region.

Acute Disease↗
PubMed1995

Risk factors for development of first symptomatic Giardia infection among infants of a birth cohort in rural Egypt.

Giardia infection is associated with diarrheal diseases among infants and young children in both industrialized and developing countries. A study was conducted to demonstrate the predisposing factors for occurrence of the first symptomatic Giardia infection among infants in rural Egypt. The study cohort was followed from birth through the first year of life. Univariate and multivariate analyses of data revealed that infants less than six months of age were at special risk for developing their first symptomatic infection compared with infants more than six months of age. Analysis of the data, furthermore, revealed an increased risk of infant Giardia infection associated with living in a household without a latrine (relative risk [RR] = 2.63, confidence interval [CI] = 1.4-4.9, P < 0.05), a mud floor in the sleeping rooms (RR = 1.79, CI = 1.O30-3.0, P < 0.05), and household exposure to more than 10 chickens (RR = 2.5, CI = 1.13-5.56, P < 0.05). In contrast, the mother's education beyond the primary level (RR = 0.28, CI = 0.09-0.85, P < 0.05), drinking water stored in metallic containers (RR = 0.33, CI = 0.11-0.98, P < 0.05), and male sex (RR = 0.52, CI = 0.3-0.89, P < 0.05) were associated with decreased risk of Giardia infection. These data suggest that in addition to age of infants, poverty, low education, gender discrimination, and certain environmental conditions potentiated the risk for developing the first symptomatic infection.

Animals↗
PubMed1993

Seroprevalence of human immunodeficiency virus type 1 infection in Zambian children with tuberculosis.

Descriptions in the medical literature of human immunodeficiency virus type 1 (HIV-1) in children with tuberculosis (TB) are scanty. This study determined the seroprevalence of HIV-1 in 237 hospitalized children between the ages of 1 month and 14 years with a clinical diagnosis of TB (125 males and 112 females) and in 242 control children (149 males and 93 females). The overall HIV-1 seroprevalence rate in patients with TB was 37% (88 of 237) compared with 10.7% (26 of 242) among the control group (P < 0.00001: odds ratio 5.37, 95% confidence interval = 3.21 < 5.37 < 9.47). HIV-1 seropositivity in children with TB ranged from 53% (31 of 58) in the 12- to 18-month age group to 14% (9 of 61) in the 10- to 14-year-olds. The risk of TB attributable to HIV infection was 29%. The predominant clinical presentation in both seronegative (84.6%) and seropositive (89.7%) groups was that of pulmonary TB and there were no significant differences in clinical presentation between the two groups of patients. Only 54.8% of the patients attended follow-up clinics regularly whereas 32% were lost to follow-up within 3 months. Bacillus Calmette-Guérin vaccination coverage was 87.3% among TB patients and 90.5% in the controls. No significant differences in B. Calmette-Guérin vaccination rates between the seronegative and seropositive children were seen. Coinfection with HIV and TB in children is now one of the major public health problems in Zambian children.

AIDS-Related Opportunistic Infections↗
PubMed1992

Trimethoprim/sulfamethoxazole remains active against enterotoxigenic Escherichia coli and Shigella species in Guadalajara, Mexico.

Bacterial isolates obtained from fecal cultures of U.S. adults in Guadalajara, Mexico, with diarrhea developing during the summers of 1987, 1988, and 1989 were tested for in vitro antimicrobial susceptibility. No resistance was seen among 220 enterotoxigenic Escherichia coli isolates nor among 89 Shigella strains to aztreonam, norfloxacin, ciprofloxacin, gentamicin, or furazolidone. High level (greater than 1000 micrograms/ml) resistance to trimethoprim/sulfamethoxazole (TMP/SMX) was found in 7% of E. coli and 3% of Shigella strains. Susceptibility patterns of 27 E. coli strains derived from fecal cultures of Mexican infants in Guadalajara with diarrhea during the same time period showed similar results, possibly reflecting the presence of a common microbial reservoir. The study serves as a baseline for newer antimicrobials (fluoroquinolones and aztreonam) where no resistance is currently seen and provides evidence of the continuing value of TMP/SMX for therapy of diarrhea among travelers to Gudalajara and perhaps other areas of Mexico.

Diarrhea↗
PubMed1988

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, 6.8% of the subjects had elevated levels of antibody to the enterotoxin of V. cholerae O1 by the immunoglobulin G enzyme-linked immunosorbent assay. Recent infection, defined on the basis of elevations in both vibriocidal and antitoxin antibodies, had occurred in 1.3% of the subjects. When subjects who reported Brucella infection, travel to a cholera-endemic area, and/or cholera vaccination within a year of the study were removed from the analysis, a prevalence of recent infection of 0.89% was obtained. Significantly higher titers of vibriocidal antibody were found in those with exposure to seawater (fishermen, shrimpers, merchant marines, and dock workers) than in those without such exposure (P less than 0.005). Furthermore, titers of antitoxin antibody were significantly higher in those who consumed shellfish than in nonconsumers. Finally, titers of vibriocidal antibody were significantly higher in Vietnamese subjects than in non-Vietnamese subjects. The results of this study indicate that an endemic focus of infection with V. cholerae occurs in this area.

Antibodies, Bacterial↗
PubMed1987

Use of norfloxacin in the treatment of acute diarrheal disease.

In studies conducted in seven countries, 392 persons with acute diarrhea were enrolled and randomly assigned to one of three regimens. In order to compare the effectiveness of various therapies for acute gastroenteritis, patients were treated for five days with either norfloxacin, 400 mg twice daily, norfloxacin, 400 mg three times a day, or trimethoprim/sulfamethoxazole, (160 mg/800 mg) twice daily. Clinical cure occurred in 89 percent (lower dose) and 91 percent (higher dose) of those treated with norfloxacin, compared with 78 percent of those receiving trimethoprim/sulfamethoxazole; cure rates in each treatment group were greater when the patient's stool contained fecal leukocytes. In 105 of 106 (99 percent) patients treated with either dose of norfloxacin and in 49 of 52 (94 percent) trimethoprim/sulfamethoxazole-treated subjects, the bacterial enteropathogen identified in the pretreatment stool was eradicated on the posttreatment specimen. Two percent (two patients) of those receiving the lower dose of norfloxacin, 3 percent (two patients) of those receiving trimethoprim/sulfamethoxazole, and 4 percent (three patients) of those receiving the higher dose of norfloxacin experienced minor and transient adverse hematologic or blood chemistry reactions. In addition, mild cutaneous reactions that were attributed to the study medications developed in two patients receiving the higher dose of norfloxacin and in three patients who received trimethoprim/sulfamethoxazole. These studies indicate that norfloxacin is safe and effective therapy for bacterial diarrhea.

Acute Disease↗
PubMed1987

Clinical presentation as a guide to therapy for travelers' diarrhea.

To better define the role of antimicrobial therapy among U.S. travelers in Mexico, clinical and nonculture laboratory parameters were compared for 56 patients with shigellosis and 204 others with diarrhea of other causes. The presence of fever, stool mucus and blood, and fecal leukocytes were significantly more common among patients with shigellosis (p less than 0.001) who also tended not to present with mild diarrhea (p less than 0.05). However, clinical and laboratory parameters were either too insensitive or too nonspecific to be useful in identifying most cases of shigellosis or in excluding the likelihood of its presence. Patients with mild clinical presentations, regardless of etiology, experienced resolution of disease sooner than those with moderate to severe presentations (p less than 0.01), but withholding therapy from patients with mild presentations resulted in 48% of these patients remaining ill at the end of 48 hours. Based on these findings, the authors advise empiric use of antimicrobial agents in travelers with diarrhea associated with fever, bloody stools, or fecal leukocytes, and for all travelers with moderate and severe diarrhea. If therapy is withheld from patients with initially mild presentations, a proportion might still require therapy, possibly an antimicrobial agent, for optimal control of symptoms.

Diarrhea↗
PubMed1987

Enteroadherent Escherichia coli as a cause of diarrhea among children in Mexico.

Enteropathogenic Escherichia coli (EPEC) often exhibits localized adherence or diffuse adherence to HEp-2 cells. We recently provided evidence that HEp-2 cell-adherent or enteroadherent E. coli (EAEC) not belonging to EPEC serogroups was the cause of diarrhea among U.S. travelers to Mexico. In the present study, we looked for EAEC and EPEC in stool specimens from 154 children with acute diarrhea and 137 well children seen at several outpatient clinics in Guadalajara, Mexico. EAEC showing localized adherence (EAEC-L) was isolated from 13.0% of the patients and 0.7% of the controls (P less than 0.0001). EAEC showing diffuse adherence (EAEC-D) was recovered from 20.8% of the patients and 7.3% of the controls (P less than 0.001). EPEC was isolated from 4.5 and 6.7% of the patients and controls, respectively. Among all enteropathogens, only enterotoxigenic E. coli occurred as commonly (21.4%) as EAEC-D and EAEC-L did in children with diarrhea. Of the EAEC-L strains isolated from children with diarrhea, 20% belonged to recognized EPEC serogroups, and 3.1% of EAEC-D strains belonged to recognized EPEC serogroups. This study suggests that EAEC may be an important pediatric enteropathogen in Mexican children with diarrhea and further supports the observation that adherence to HEp-2 cells may be a marker of virulence independent of EPEC serogroup among E. coli strains.

Bacterial Adhesion↗
PubMed1987

Ciprofloxacin or trimethoprim-sulfamethoxazole as initial therapy for travelers' diarrhea. A placebo-controlled, randomized trial.

The efficacy of ciprofloxacin was compared with that of trimethoprim-sulfamethoxazole in a placebo-controlled trial of the 5-day treatment of acute diarrhea among 181 adults recently arrived in Guadalajara, Mexico. Both antimicrobial agents were significantly (p less than 0.0001) more efficacious than placebo in the treatment of diarrhea, with the average duration of diarrhea being 29, 20, and 81 hours, respectively, in the ciprofloxacin, trimethoprim-sulfamethoxazole, and placebo treatment groups. The antimicrobial agents were also more efficacious than placebo in treating diarrhea caused by enterotoxigenic Escherichia coli, invasive enteropathogens, and unknown pathogens. Both antimicrobials were effective in treating mild-to-moderate and moderate-to-severe disease, and both were well tolerated. Ciprofloxacin appears to be a logical alternative to trimethoprim-sulfamethoxazole in the initial treatment of acute travelers' diarrhea.

Adult↗
PubMed1986

Lack of emergence of resistant fecal flora during successful prophylaxis of traveler's diarrhea with norfloxacin.

Norfloxacin, a new quinolone carboxylic acid derivative, was compared with an identical-appearing placebo preparation in a prospective, randomized, double-blind trial for prevention of traveler's diarrhea among 120 U.S. students arriving in Mexico. Prophylaxis was continued for 2 weeks. Diarrhea was defined as four unformed stools in 24 h plus an additional symptom of enteric disease. In the norfloxacin prophylaxis group, 4 of 56 subjects (7%) experienced diarrhea, compared with 36 of 59 subjects (61%) in the placebo group. The difference was significant (P less than 0.0001). In contrast to our previous experience with use of trimethoprim-sulfamethoxazole to prevent traveler's diarrhea, quantitative stool cultures in the norfloxacin-treated group revealed a significant decline of normal aerobic fecal flora during prophylaxis (P less than 0.0005). Among stool samples from norfloxacin-treated subjects, 32 of 38 (84%) cultured on day 7 and 34 of 37 (92%) cultured on day 14 had no gram-negative bacilli. After norfloxacin was discontinued, fecal flora returned to pretreatment levels. No gram-negative aerobic flora resistant to norfloxacin were found during weekly quantitative cultures before, during, or after therapy.

Bacteria↗