RESUMEN
BACKGROUND: Traveler's diarrhea is the most common medical complaint of international visitors to developing regions. Previous findings suggested that noroviruses (NoVs) are an underappreciated cause of traveler's diarrhea. METHODS. In the present study, we sought to define the presence of NoVs in 320 acute diarrheic stool samples collected from 299 US students who traveled to Guadalajara, Cuernavaca, or Puerto Vallarta, Mexico, during the period from 2007 through 2008. Conventional and quantitative real-time polymerase chain reaction assays were used to detect and determine NoV loads in stool samples. NoV strains were characterized by purification of viral RNA followed by sequencing of the viral capsid protein 1 gene. Sequences were compared using multiple sequence alignment, and phylogenetic trees were generated to evaluate the evolutionary relatedness of the viral strains associated with cases of traveler's diarrhea. RESULTS: NoV RNA was detected in 30 (9.4%) of 320 samples. Twelve strains belonged to genogroup I, and 18 strains belonged to genogroup II. NoV prevalence was higher in the winter season than in the summer season (23% vs 7%, respectively; P = .001). The cDNA viral loads of genogroup I viruses were found to be 500-fold higher than those of genogroup II strains. Phylogenetic analysis revealed a diverse population of NoV strains over different locations and years. CONCLUSIONS: NoV strains are important causes of traveler's diarrhea in Mexico, especially during the wintertime, and US students in Mexico may represent a suitable group for future NoV vaccine efficacy trials.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Infecciones por Caliciviridae/virología , Gastroenteritis/epidemiología , Gastroenteritis/virología , Norovirus/aislamiento & purificación , Viaje , Adulto , Infecciones por Caliciviridae/patología , Proteínas de la Cápside/genética , Análisis por Conglomerados , Diarrea/epidemiología , Diarrea/patología , Diarrea/virología , Heces/virología , Femenino , Gastroenteritis/patología , Genotipo , Humanos , Masculino , México , Persona de Mediana Edad , Epidemiología Molecular , Norovirus/clasificación , Norovirus/genética , Filogenia , Reacción en Cadena de la Polimerasa , ARN Viral/genética , Análisis de Secuencia de ADN , Homología de Secuencia , Estados Unidos , Carga Viral , Adulto JovenRESUMEN
BACKGROUND: Simple methods for detecting secretory immunoglobulin A (sIgA) immune responses following natural enteric infection and oral immunization are needed. METHODS: Fourteen students from the United States acquiring enterotoxigenic Escherichia coli (ETEC) diarrhea in Mexico were studied for fecal immunoglobulin A (IgA) response to their homologous infecting ETEC and to heat-labile (LT) toxin of ETEC using Dot-Blot microfiltration and enzyme-linked immunosorbent assay (ELISA) methods. Paired stool samples were collected on the day of presentation and 5 days later. RESULTS: Twelve of 14 (86%) patients with ETEC diarrhea (5 heat-stable [ST]/LT positive, 4 LT-only, and 5 ST-only) developed sIgA antibodies directed against their homologous ETEC and 6 (66%) of the 9 patients harboring ST/LT or LT-only strains developed sIgA LT-antibody responses. Single fecal samples from 9 healthy controls were negative for ETEC specific antibodies. CONCLUSIONS: Patients with diarrhea due to noninvasive ST/LT ETEC and LT ETEC commonly produce a specific sIgA antibody response early in the illness. We feel that the methods employed will be useful to detect antibodies during natural infection by enteric pathogens and following oral enteric vaccine administration.
Asunto(s)
Diarrea/inmunología , Infecciones por Escherichia coli/inmunología , Inmunoglobulina A/inmunología , Viaje , Formación de Anticuerpos , Antígenos Bacterianos/inmunología , Diarrea/microbiología , Enterotoxinas/inmunología , Ensayo de Inmunoadsorción Enzimática , Humanos , México/epidemiología , Estados UnidosAsunto(s)
Antiinfecciosos/administración & dosificación , Antidiarreicos/administración & dosificación , Diarrea/tratamiento farmacológico , Loperamida/administración & dosificación , Ofloxacino/administración & dosificación , Viaje , Adulto , Esquema de Medicación , Quimioterapia Combinada , Femenino , Humanos , Masculino , MéxicoRESUMEN
Enteroaggregative Escherichia coli (EAEC) has been reported to cause traveler's diarrhea and persistent diarrhea in children in developing countries and in immunocompromised patients. To clarify the prevalence of EAEC in traveler's diarrhea, we studied 636 US, Canadian, or European travelers with diarrhea: 218 in Guadalajara, Mexico (June--August 1997 and 1998), 125 in Ocho Rios, Jamaica (September 1997--May 1998), and 293 in Goa, India (January 1997--April 1997 and October 1997--February 1998). Stool samples were tested for conventional enteropathogens. EAEC strains were identified by use of the HEp-2 assay. EAEC was isolated in 26% of cases of traveler's diarrhea (ranging from 19% in Goa to 33% in Guadalajara) and was second only to enterotoxigenic E. coli as the most common enteropathogen in all areas. Identification of EAEC reduced the number of cases for which the pathogen was unknown from 327 (51%) to 237 (37%) and explained 28% of cases with unknown etiology. EAEC was a major cause of traveler's diarrhea in 3 geographically distinct study areas.
Asunto(s)
Diarrea/microbiología , Infecciones por Escherichia coli/microbiología , Salud Global , Viaje , Adulto , Diarrea/epidemiología , Escherichia coli/clasificación , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Femenino , Humanos , India/epidemiología , Jamaica/epidemiología , Masculino , México/epidemiología , Prevalencia , Células Tumorales CultivadasRESUMEN
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.
Asunto(s)
Escherichia coli/efectos de los fármacos , Heces/microbiología , Resistencia al Trimetoprim , Adolescente , Adulto , Antibacterianos/uso terapéutico , Profilaxis Antibiótica , Farmacorresistencia Microbiana , Escherichia coli/aislamiento & purificación , Femenino , Humanos , Masculino , México , ViajeRESUMEN
The emergence of resistant enteropathogens has been reported worldwide. Few data are available on the contemporary in vitro activities of commonly used antimicrobial agents against enteropathogens causing traveler's diarrhea (TD). The susceptibility patterns of antimicrobial agents currently available or under evaluation against pathogens causing TD in four different areas of the world were evaluated. Pathogens were identified in stool samples from U.S., Canadian, or European adults (18 years of age or older) with TD during 1997, visiting India, Mexico, Jamaica, or Kenya. MICs of 11different antimicrobials were determined against 284 bacterial enteropathogens by the agar dilution method. Ciprofloxacin, levofloxacin, ceftriaxone, and azithromycin were highly active in vitro against the enteropathogens, while traditional antimicrobials such as ampicillin, trimethoprim, and trimethoprim/sulfamethoxazole showed high levels and high frequencies of resistance. Rifaximin, a promising and poorly absorbable drug, had an MIC at which 90% of the strains tested were inhibited of 32 microg/ml, 250 times lower than the concentration of this drug in the stools. Amdinocillin, nalidixic acid, and doxycycline showed moderate activity. Fluoroquinolones are still the drugs of choice for TD in most regions of the world, although our study has a limitation due to the lack of Escherichia coli samples from Kenya and possible bias in selection of the patients for evaluation. Azithromycin and rifaximin should be considered as promising new agents. The widespread in vitro resistance of the traditional antimicrobial agents reported since the 1980s and the new finding of resistance to fluoroquinolones in Southeast Asia are the main reasons for monitoring carefully the antimicrobial susceptibility patterns worldwide and for developing and evaluating new antimicrobial agents for the treatment of TD.
Asunto(s)
Antibacterianos/farmacología , Diarrea/microbiología , Enterobacteriaceae/efectos de los fármacos , Viaje , India , Jamaica , Kenia , México , Pruebas de Sensibilidad MicrobianaRESUMEN
Almost two of three tourists developed traveller's diarrhoea during 2-week stays at high-risk destinations. Large differences in infection rates between hotels were seen. Patients with milder forms of diarrhoea show a similar chronology to those more severely affected. Although enterotoxigenic Escherichia coil was the most frequent cause, viral pathogens were detected more often than in other studies.
Asunto(s)
Diarrea/epidemiología , Diarrea/etiología , Viaje , Brasil/epidemiología , Culinaria , Estudios Transversales , Diarrea/clasificación , Diarrea/prevención & control , Heces/microbiología , Microbiología de Alimentos , Humanos , India/epidemiología , Jamaica/epidemiología , Kenia/epidemiología , Factores de Riesgo , Índice de Severidad de la Enfermedad , Encuestas y CuestionariosRESUMEN
We examined stool samples from travelers for secretory immunoglobulin A (sIgA) to enteroaggregative Escherichia coli (EAEC) during episodes of acute diarrhea. Ten paired samples from 10 patients with diarrhea caused by EAEC were examined for the presence of specific sIgA by dot blot and Western blot immunoassays. Five samples were positive by dot blotting, and two samples were positive by Western blotting.
Asunto(s)
Diarrea/diagnóstico , Infecciones por Escherichia coli/diagnóstico , Inmunoglobulina A/análisis , Adulto , Antígenos Bacterianos/análisis , Antígenos Bacterianos/inmunología , Western Blotting , Enfermedad Crónica , Diarrea/inmunología , Infecciones por Escherichia coli/inmunología , Heces/microbiología , Humanos , Immunoblotting , Intestinos/inmunología , México , ViajeRESUMEN
BACKGROUND: Between December 6, 1994 and March 10, 1996, a study of the etiology of diarrhea was carried out among 332 travelers to five all-inclusive hotels in Negril, Jamaica. METHODS: Stool specimens were collected and sent to Montego Bay for laboratory analysis. Escherichia coli strains isolated at the Jamaican laboratory were sent to Houston for toxin testing. RESULTS: A recognized enteropathogen was found in 118 of the 332 (35.5%) cases. Enterotoxigenic E. coli (ETEC) were the most commonly identified pathogen (87/332; 26.2%) followed by Salmonella (4.2%) and Shigella (4.2%). Clustering of etiologically defined cases was studied at each hotel. A cluster was defined as 2 or more cases with the same pathogen identified in the same hotel within 7 days. In the 3 hotels with the highest number of cases of diarrhea, enteropathogens were part of a cluster in 65 of 99 cases (65.7%) of diarrhea of which an etiologic agent was identified. In the other 2 hotels, only 4 of 20 cases (20%) occurred in clusters. CONCLUSIONS: A total of 25 clusters of travelers' diarrhea cases was detected at the five hotels during the study period. Seventeen of 25 (68%) ETEC isolations occurred as part of a clustering of diarrhea cases. The largest outbreak of pathogen-identified diarrhea consisted of 7 cases of ETEC producing both heat-stable and heat-labile enterotoxins. In the Jamaican hotels with all inclusive meal packages most diarrhea cases occurred as small clusters, presumably as the result of foodborne outbreaks.
Asunto(s)
Diarrea/epidemiología , Diarrea/microbiología , Infecciones por Escherichia coli/epidemiología , Escherichia coli/aislamiento & purificación , Viaje , Infecciones por Campylobacter/epidemiología , Campylobacter jejuni/aislamiento & purificación , Análisis por Conglomerados , Diarrea/parasitología , Brotes de Enfermedades , Disentería Bacilar/epidemiología , Heces/microbiología , Heces/parasitología , Enfermedades Transmitidas por los Alimentos/epidemiología , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/parasitología , Giardiasis/epidemiología , Humanos , Jamaica/epidemiología , Infecciones por Salmonella/epidemiología , Encuestas y CuestionariosRESUMEN
The relationship between enterotoxigenic Escherichia coli (ETEC) and travelers' diarrhea was examined in a high-risk area in 1992-1997. Toxin patterns, colonization-factor antigens (CFAs), and in vitro antimicrobial susceptibility were determined. In total, 928 US students with diarrhea acquired in Guadalajara, Mexico, were screened for enteric pathogens. Diagnosis of ETEC infection was done with oligonucleotide probes. ETEC was isolated in 19.9% of the travelers with diarrhea. CFAs were identified in 51% of the ETEC strains. The highest CFA frequency was observed among heat-stable isolates. Ampicillin, furazolidone, and sulfisoxazole resistance of ETEC increased during the study period. ETEC isolation rates and CFA patterns varied little during the 6 years of the study, which has implications for immunoprophylactic strategies. The finding that differences in the results of ribotyping and plasmid analysis change over time suggests that multiple strains of ETEC were responsible for the illness in the region studied.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/biosíntesis , Diarrea/microbiología , Enterotoxinas/biosíntesis , Infecciones por Escherichia coli/microbiología , Escherichia coli/fisiología , Proteínas Fimbrias , Adolescente , Adulto , ADN Ribosómico/análisis , Diarrea/epidemiología , Enterobacteriaceae/aislamiento & purificación , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Heces/microbiología , Humanos , México , Pruebas de Sensibilidad Microbiana , Plásmidos/genética , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , ARN Ribosómico 23S/genética , Estudiantes , ViajeRESUMEN
CONTEXT: Traveler's diarrhea (TD) can incapacitate travelers. Characteristics of TD could be helpful in identifying individuals who might benefit from a vaccine against TD. OBJECTIVE: To determine epidemiology, etiology, and impact of TD in Jamaica. Design Two-armed, cross-sectional survey conducted between March 1996 and May 1997. SETTING: Sangster International Airport and 10 hotels in Montego Bay area, Jamaica. SUBJECTS: To investigate epidemiology and impact, 30369 short-term visitors completed a questionnaire just before boarding their homebound aircrafts. To investigate etiology, 322 patients (hotel guests) with TD provided stool samples. MAIN OUTCOME MEASURES: Attack and incidence rates of reported diarrhea and of classically defined TD (> or =3 unformed stool samples in 24 hours and > or =1 accompanying symptom), incapacity, risk factors, and etiology. RESULTS: The attack rate for diarrhea was 23.6% overall, with 11.7% having classically defined TD. For a mean duration of stay of 4 to 7 days, the incidence rate was 20.9% (all TD) and 10.0% (classic TD). Among airport respondents, the incapacity lasted a mean of 11.6 hours. Less than 3% of all travelers avoided potentially high-risk food and beverages. The most frequently detected pathogens were enterotoxigenic Escherichia coli, Rotavirus, and Salmonella species. CONCLUSIONS: A realistic plan for reducing TD is needed. Preventive measures such as the improvement of hygienic conditions at the destination, and/or the development of vaccines against the most frequent pathogens associated with TD may contribute toward achieving this goal.
Asunto(s)
Diarrea/epidemiología , Viaje , Adolescente , Adulto , Costo de Enfermedad , Estudios Transversales , Diarrea/economía , Diarrea/etiología , Diarrea/terapia , Femenino , Humanos , Incidencia , Jamaica/epidemiología , Masculino , Persona de Mediana Edad , Calidad de Vida , Factores de Riesgo , Encuestas y CuestionariosAsunto(s)
Diarrea/prevención & control , Lactobacillus , Probióticos/uso terapéutico , Preescolar , Países en Desarrollo , Humanos , Lactante , Perú , ViajeRESUMEN
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.
Asunto(s)
Infecciones Bacterianas/diagnóstico , Diarrea Infantil/diagnóstico , Diarrea/diagnóstico , Heces/citología , Leucocitos , Sangre Oculta , Enfermedad Aguda , Adulto , Niño , Preescolar , Humanos , Lactante , México , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Viaje , Estados UnidosRESUMEN
Cholera is a dramatic clinical illness that requires rapid diagnosis and aggressive therapy. Clinical signs and symptoms of mild, moderate and severe dehydration must be determined, before beginning fluid therapy. Fluid therapy has 2 phases: rehydration (first 3 to 4 hours to correct deficits) and maintenance (to match continuing losses). The route and speed of fluid administration will depend on the degree of dehydration. Patients with severe dehydration should be treated intravenously, as should those patients who do not tolerate oral rehydration solution (ORS). Ringer's lactate is the preferred intravenous solution, although normal saline may be used along with ORS. For most patients with cholera, an ORS using one of the higher sodium-containing solutions and plain water optimally provide the fluid and salt needed. Close monitoring of intake, outputs and hydration status should be performed for all patients. Antimicrobial therapy should be given to moderately and severely ill patients in order to decrease the volume of fluids lost and to shorten the period of excretion of vibrios.
Asunto(s)
Antiinfecciosos/administración & dosificación , Cólera/terapia , Fluidoterapia/métodos , Humanos , Guías de Práctica Clínica como AsuntoRESUMEN
The present study was undertaken to compare the efficacy of a new calmodulin antagonist, zaldaride maleate, with that of placebo or loperamide in persons with traveler's diarrhea. One hundred seventy-nine patients were randomized to receive loperamide (4 mg followed by 2 mg after each unformed stool), zaldaride maleate (20 mg four times per day), or placebo. During the initial 48 hours of therapy, zaldaride maleate decreased the number of unformed stools by 30% and the duration of illness by 23% when compared with placebo. Loperamide was superior to both zaldaride maleate and placebo during the initial hours of treatment. However, after 48 hours of treatment, loperamide and zaldaride maleate were equally efficacious, decreasing by > 50% the number of unformed stools passed in a 24-hour interval (P, not significant), and were both superior when compared with placebo (P < .0001 and P = .0048, respectively). The apparent superiority of loperamide early in the course of therapy appeared to be related to a loading-dose effect and not to any differences in antidiarrheal properties.
Asunto(s)
Antidiarreicos/uso terapéutico , Bencimidazoles/uso terapéutico , Calmodulina/antagonistas & inhibidores , Diarrea/tratamiento farmacológico , Loperamida/uso terapéutico , Enfermedad Aguda , Adulto , Bacterias/aislamiento & purificación , Diarrea/microbiología , Método Doble Ciego , Heces/microbiología , Femenino , Humanos , Masculino , México , Viaje , Resultado del TratamientoRESUMEN
Plasmid DNA analysis and antibiotic susceptibilities were used to study strains of Shigella sonnei isolated from U.S. travelers to Guadalajara, Mexico, over a period of seven years (1986 to 1992). One hundred sixty-one isolates were analyzed. By the use of cluster analysis, eight different plasmid profiles were identified during this interval. At any point in time, three to seven different plasmid profiles were present in this population. The introduction of strains that carried a new plasmid with a molecular mass of 5.1 MDa was coincidental with an increase in isolation of S. sonnei in 1988. This new plasmid was present in 87.5% of the isolates that were resistant to chloramphenicol. Shigellosis in Guadalajara follows a pattern of hyperendemic transmission with transient peaks of high-frequency isolation of S. sonnei. This pattern results from the concurrent presence of a heterogeneous group of strains as opposed to the widespread transmission of one or a few clones.
Asunto(s)
Diarrea/microbiología , Shigella sonnei/aislamiento & purificación , Viaje , Humanos , México , Pruebas de Sensibilidad Microbiana , Plásmidos , Shigella sonnei/efectos de los fármacos , Estudiantes , Factores de TiempoRESUMEN
Ninety-eight women-infant pairs were followed for up to 50 weeks in the northern part of Guadalajara, Mexico, from August 1986 to July 1987 as part of a community-based, prospective study of the relation between infant feeding patterns and enterotoxigenic Escherichia coli producing heat-labile toxin (LT-ETEC) diarrheal disease. Strictly formula-fed children had an incidence of diarrhea over three times that of strictly breast-fed infants and twice that of breast-fed and supplementally fed children. Strictly formula-fed infants colonized by LT-ETEC were symptomatic for diarrhea nearly three times as often as strictly breast-fed infants and twice as often as infants receiving a mixed diet. The fitting of parametric hazard models to durations until LT-ETEC colonization revealed that the hazard for the first colonization was time invariant. The hazard of diarrhea increased by 400-500% during the rainy season or among children 3 months of age or older who received avena, a barley drink. The best-fitting hazard models to durations until symptomatic expression of LT-ETEC infection all increased through time. This hazard was inversely impacted by the overall amount of LT-ETEC-specific, immunoglobulin A antibodies the infant received via the mother's breast milk and by the provision of traditional medicinal teas.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Lactancia Materna , Diarrea Infantil/epidemiología , Enterotoxinas/biosíntesis , Infecciones por Escherichia coli/epidemiología , Proteínas de Escherichia coli , Salud Urbana , Toxinas Bacterianas/análisis , Estudios de Cohortes , Diarrea Infantil/microbiología , Enterotoxinas/análisis , Escherichia coli/metabolismo , Infecciones por Escherichia coli/microbiología , Femenino , Humanos , Inmunoglobulina A/análisis , Lactante , Alimentos Infantiles , Recién Nacido , México/epidemiología , Leche Humana/inmunología , Leche Humana/microbiología , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo , Estaciones del Año , Factores SocioeconómicosRESUMEN
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.