RESUMO
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.
Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus/isolamento & purificação , Viagem , Adulto , Infecções por Caliciviridae/patologia , Proteínas do Capsídeo/genética , Análise por Conglomerados , Diarreia/epidemiologia , Diarreia/patologia , Diarreia/virologia , Fezes/virologia , Feminino , Gastroenterite/patologia , Genótipo , Humanos , Masculino , México , Pessoa de Meia-Idade , Epidemiologia Molecular , Norovirus/classificação , Norovirus/genética , Filogenia , Reação em Cadeia da Polimerase , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência , Estados Unidos , Carga Viral , Adulto JovemRESUMO
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.
Assuntos
Diarreia/imunologia , Infecções por Escherichia coli/imunologia , Imunoglobulina A/imunologia , Viagem , Formação de Anticorpos , Antígenos de Bactérias/imunologia , Diarreia/microbiologia , Enterotoxinas/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos , México/epidemiologia , Estados UnidosAssuntos
Anti-Infecciosos/administração & dosagem , Antidiarreicos/administração & dosagem , Diarreia/tratamento farmacológico , Loperamida/administração & dosagem , Ofloxacino/administração & dosagem , Viagem , Adulto , Esquema de Medicação , Quimioterapia Combinada , Feminino , Humanos , Masculino , MéxicoRESUMO
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.
Assuntos
Diarreia/microbiologia , Infecções por Escherichia coli/microbiologia , Saúde Global , Viagem , Adulto , Diarreia/epidemiologia , Escherichia coli/classificação , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Feminino , Humanos , Índia/epidemiologia , Jamaica/epidemiologia , Masculino , México/epidemiologia , Prevalência , Células Tumorais CultivadasRESUMO
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.
Assuntos
Escherichia coli/efeitos dos fármacos , Fezes/microbiologia , Resistência a Trimetoprima , Adolescente , Adulto , Antibacterianos/uso terapêutico , Antibioticoprofilaxia , Resistência Microbiana a Medicamentos , Escherichia coli/isolamento & purificação , Feminino , Humanos , Masculino , México , ViagemRESUMO
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.
Assuntos
Antibacterianos/farmacologia , Diarreia/microbiologia , Enterobacteriaceae/efeitos dos fármacos , Viagem , Índia , Jamaica , Quênia , México , Testes de Sensibilidade MicrobianaRESUMO
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.
Assuntos
Diarreia/epidemiologia , Diarreia/etiologia , Viagem , Brasil/epidemiologia , Culinária , Estudos Transversais , Diarreia/classificação , Diarreia/prevenção & controle , Fezes/microbiologia , Microbiologia de Alimentos , Humanos , Índia/epidemiologia , Jamaica/epidemiologia , Quênia/epidemiologia , Fatores de Risco , Índice de Gravidade de Doença , Inquéritos e QuestionáriosRESUMO
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.
Assuntos
Diarreia/diagnóstico , Infecções por Escherichia coli/diagnóstico , Imunoglobulina A/análise , Adulto , Antígenos de Bactérias/análise , Antígenos de Bactérias/imunologia , Western Blotting , Doença Crônica , Diarreia/imunologia , Infecções por Escherichia coli/imunologia , Fezes/microbiologia , Humanos , Immunoblotting , Intestinos/imunologia , México , ViagemRESUMO
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.
Assuntos
Diarreia/epidemiologia , Diarreia/microbiologia , Infecções por Escherichia coli/epidemiologia , Escherichia coli/isolamento & purificação , Viagem , Infecções por Campylobacter/epidemiologia , Campylobacter jejuni/isolamento & purificação , Análise por Conglomerados , Diarreia/parasitologia , Surtos de Doenças , Disenteria Bacilar/epidemiologia , Fezes/microbiologia , Fezes/parasitologia , Doenças Transmitidas por Alimentos/epidemiologia , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/parasitologia , Giardíase/epidemiologia , Humanos , Jamaica/epidemiologia , Infecções por Salmonella/epidemiologia , Inquéritos e QuestionáriosRESUMO
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.