RESUMEN
Twenty-two atypical enteroaggregative Escherichia coli isolates from a previous epidemiological study harboring EAEC virulence genes were examined for their adhesion properties. Nine strains showed a typical aggregative adherence (AA) pattern, while 13 strains showed variant AA, such as AA with lined up cells characteristic of the chain-like adhesion (CLA) and AA mainly to HeLa cells characteristic of the diffuse adherence (DA). The aggregative forming pilus (AFP) genes afpA2 and afpR were detected only in strain Q015B, which exhibited an AA/DA pattern. Using Tn5-based transposon mutagenesis on Q015B strain, we identified a 5517-bp open reading frame (ORF) encoding a predicted 1838-amino-acid polypeptide that is genetically related to a putative filamentous hemagglutinin identified in E. coli strain 7-233-03_S3_C2. Therefore, the ORF was named orfHA. The regions flanking orfHA were sequenced and two ORFs were found; upstream, an ORF that encodes a 603-amino-acid polypeptide with 99% identity to hemolysin secretion/activation proteins of the ShlB/FhaC/HecB family, and downstream, another ORF, which encodes a 632-amino-acid polypeptide with 72% identity to the glycosyltransferase EtpC. An orfHA mutant (Q015BΔorfHA) was constructed from strain Q015B. Q015BΔorfHA strain did not adhere to HeLa cells, whereas Q015BΔ orfHA transformed with a pACYC184 plasmid carrying orfHA restored the AA/DA phenotype of strain Q015B. Furthermore, the Q015ΔorfHA mutant had a marked effect on the ability of strain Q015B to kill the larvae of Galleria mellonella. Our results suggest that the AA/DA pattern of strain Q015B is mediated by a hemagglutinin-associated protein which also contributes to its virulence in the G. mellonella model.
Asunto(s)
Infecciones por Escherichia coli , Proteínas de Escherichia coli , Humanos , Escherichia coli/metabolismo , Hemaglutininas/metabolismo , Células HeLa , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Virulencia/genética , Adhesión Celular , Adhesión Bacteriana/genética , Infecciones por Escherichia coli/genética , MutagénesisRESUMEN
BACKGROUND: In previous studies, we have shown that atypical enteropathogenic Escherichia coli (aEPEC) strains are important diarrheal pathogens among Brazilian children. In the characterization of a collection of 126 aEPEC strains, we identified 29 strains expressing the localized-like adherence (LAL) pattern on HEp-2 cells and harboring large plasmids in the range of 60 to 98 MDa. In this study, we examined 18 of these strains for their ability to transfer the LAL phenotype to a E. coli K-12 C600 strain. RESULTS: In conjugation experiments, using eight strains which were resistant to one or more antimicrobials and positive for F-pili genes (traA), we were able to cotransfer antimicrobial resistance markers along with adhesion genes. By transforming E. coli DH5α with plasmid DNA from strains A46 (pIS46), A66 (pIS66) and A102 (pIS102), we were able to demonstrate that genes encoding ampicillin, tetracycline and LAL were encoded on a 98-MDa conjugative plasmid. To identify a gene responsible for LAL, we constructed a transposon mutant library of A102 strain. Among 18 mutants that did not adhere to HeLa cells, four carried insertions within fimbrial genes (fimA and traJ) and agglutinin genes (tia and hek). Using these Tn5 mutants as donors, we were able to obtain kanamycin-resistant E. coli MA3456 transconjugants. Sequence analysis of the plasmid genes revealed a region exhibit to 80 and 73% amino acid similarities to the agglutinins Tia and Hek, respectively. CONCLUSION: In this study, we have identified three large conjugative plasmids, pIS46, pIS66 and pIS102, coding for antimicrobial resistance and localized-like adherence (LAL) to HeLa cells. In addition, we identified a tia/hek homolog encoded on the pIS102 plasmid, which seems to be involved in adhesion of A102 strain.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Escherichia coli Enteropatógena/genética , Proteínas de Escherichia coli/genética , Plásmidos/genética , Ampicilina/farmacología , Adhesión Bacteriana , Conjugación Genética , Escherichia coli Enteropatógena/efectos de los fármacos , Escherichia coli Enteropatógena/aislamiento & purificación , Proteínas Fimbrias/genética , Transferencia de Gen Horizontal , Células HeLa , Humanos , Kanamicina/farmacología , Pruebas de Sensibilidad Microbiana , Mutagénesis Insercional , Tetraciclina/farmacologíaRESUMEN
Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.(AU)
Asunto(s)
Escherichia coli/patogenicidad , Infecciones por Escherichia coli/epidemiología , Diarrea/diagnóstico , Diarrea/epidemiologíaRESUMEN
ABSTRACT Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.
Asunto(s)
Humanos , Diarrea/diagnóstico , Diarrea/microbiología , Escherichia coli/clasificación , Escherichia coli/fisiología , Infecciones por Escherichia coli/diagnóstico , Infecciones por Escherichia coli/microbiología , Prevalencia , Factores de Virulencia/genética , Diarrea/epidemiología , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/epidemiologíaRESUMEN
Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.
Asunto(s)
Diarrea/diagnóstico , Diarrea/epidemiología , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/epidemiologíaRESUMEN
Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.
Asunto(s)
Diarrea/diagnóstico , Diarrea/microbiología , Infecciones por Escherichia coli/diagnóstico , Infecciones por Escherichia coli/microbiología , Escherichia coli/clasificación , Escherichia coli/fisiología , Diarrea/epidemiología , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/epidemiología , Humanos , Prevalencia , Factores de Virulencia/genéticaRESUMEN
ABSTRACT Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.
RESUMEN
BACKGROUND: Enteropathogenic Escherichia coli (EPEC) are classified into typical and atypical strains based on the presence of the E. coli adherence factor (EAF) plasmid. The EAF plasmid contains the bfp (bundle-forming pilus) operon and the perABC (plasmid encoded regulator) gene cluster. A 1-kb cryptic region of EAF plasmid has been widely used as a genetic probe for EPEC detection. However, some EPEC strains may harbor an EAF plasmid lacking the EAF probe sequence, which makes the differentiation between typical and atypical a complex task. In this study, we report the genetic analysis of the EAF plasmid-encoded genes in a collection of EPEC clinical isolates. METHODS: A total of 222 EPEC clinical isolates, which were previously classified as typical (n=70) or atypical (n=152) by EAF probe reactivity, were screened for the presence of different EAF sequences by PCR and DNA hybridization. RESULTS: All typical strains possessed intact bfpA and perA genes, and most of them were positive in the PCR for EAF probe sequence. However, a subset of 30 typical strains, 22 of which belonged to O119 serogroup, presented a 1652 pb deletion in the region between 1093-bp downstream perC and 616-bp of the EAF fragment. The bfpA, bfpG, and per genes were found in all typical strains. In addition, 32 (21%) atypical strains presented the perA gene, and 20 (13.2%) also presented the bfpA gene. Among the 32 strains, 16 belonged to the O119:H2, O119:HND, and ONT:HND serotypes. All 32 atypical strains contained perA mutation frameshifts and possessed an IS1294 element upstream of the per operon as detected by PCR followed by restriction fragment length polymorphism (RFLP) typing and multiplex PCR. Among the 20 bfpA probe-positive strains, eight O119 strains possessed deletion in the bfp operon at the 3'end of bfpA due to an IS66 element. CONCLUSION: Our data show that typical O119 strains may contain a deletion within the EAF probe sequence not previously reported. This new finding suggests that care should be taken when using the previously described EAF PCR assay in epidemiological studies for the detection of typical O119 strains. In addition, we were able to confirm that some atypical strains carry vestiges of the EAF plasmid.
Asunto(s)
Adhesinas Bacterianas/genética , Escherichia coli Enteropatógena/genética , Técnicas de Diagnóstico Molecular/métodos , Sondas de Oligonucleótidos/genética , Plásmidos , Eliminación de Secuencia , Escherichia coli Enteropatógena/aislamiento & purificación , Infecciones por Escherichia coli/diagnóstico , Reacciones Falso Negativas , Datos de Secuencia Molecular , Familia de Multigenes , Hibridación de Ácido Nucleico/métodos , Reacción en Cadena de la Polimerasa/métodos , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Childhood diarrheal diseases remain highly endemic in developing areas of Brazil. The importance of Escherichia coli among children with diarrhea in these areas was unknown. This study determined the prevalence of different E. coli categories in symptomatic and asymptomatic children from low socioeconomic level rural communities in southeastern Brazil. METHODS: A total of 560 stool samples were collected from 141 children with diarrhea (< 10 years) and 419 apparently healthy controls who resided in 23 communities. E. coli isolates (n = 1943) were subjected to two multiplex PCRs developed for the detection of enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and Shiga toxin-producing E. coli (STEC). Strains were also examined for the presence of EPEC, EAEC, and DAEC by assays of adhesion to HEp-2 cells and by hybridization with specific DNA probes. RESULTS: Diarrheagenic E. coli strains were isolated from 253 (45.2%) children, and were associated with diarrhea in children aged < 5 years (p < 0.001). EAEC (20.9%), DAEC (11.6%), EPEC (9.3%) were the most frequent pathotypes, followed by ETEC (2.7%), EIEC (0.5%), and STEC (0.2%). Depending of the assay, EPEC, EAEC, and DAEC (collectively termed enteroadherent E. coli) strains were isolated in 45% to 56% of diarrhea cases, a significantly higher incidence than in controls (P < 0.05). Individually, only DAEC showed significant association with diarrhea (p < 0.05), particularly in children aged 2-5 years. CONCLUSION: This study indicates that enteroadherent E. coli is an important cause of diarrhea in children living in low socioeconomic level communities in southeastern Brazil. Our results reveal that the PCR1 assay is an excellent tool for the identification of EAEC and DAEC.
Asunto(s)
Diarrea/microbiología , Escherichia coli Enteropatógena/aislamiento & purificación , Infecciones por Escherichia coli/microbiología , Brasil/epidemiología , Preescolar , Diarrea/diagnóstico , Diarrea/economía , Diarrea/epidemiología , Escherichia coli Enteropatógena/genética , Infecciones por Escherichia coli/diagnóstico , Infecciones por Escherichia coli/economía , Infecciones por Escherichia coli/epidemiología , Heces/microbiología , Femenino , Genotipo , Humanos , Incidencia , Lactante , Masculino , Fenotipo , PobrezaRESUMEN
AIM: To evaluate the association between Helicobacter pylori (H. pylori) infection and MLH1 and MGMT methylation and its relationship with microsatellite instability (MSI). METHODS: The methylation status of the MLH1 and MGMT promoter region was analysed by methylation specific methylation-polymerase chain reaction (MSP-PCR) in gastric biopsy samples from uninfected or H. pylori-infected children (n = 50), from adults with chronic gastritis (n = 97) and from adults with gastric cancer (n = 92). MLH1 and MGMT mRNA expression were measured by real-time PCR and normalised to a constitutive gene (ß actin). MSI analysis was performed by screening MSI markers at 4 loci (Bat-25, Bat-26, D17S250 and D2S123) with PCR; PCR products were analysed by single strand conformation polymorphism followed by silver staining. Statistical analyses were performed with either the χ(2) test with Yates continuity correction or Fisher's exact test, and statistical significance for expression analysis was assessed using an unpaired Student's t-test. RESULTS: Methylation was not detected in the promoter regions of MLH1 and MGMT in gastric biopsy samples from children, regardless of H. pylori infection status. The MGMT promoter was methylated in 51% of chronic gastritis adult patients and was associated with H. pylori infection (P < 0.05); this region was methylated in 66% of gastric cancer patients, and the difference in the percentage of methylated samples between these patients and those from H. pylori-infected chronic gastritis patients was statistically significant (P < 0.05). MLH1 methylation frequencies among H. pylori-infected and non-infected chronic gastritis adult patients were 13% and 7%, respectively. We observed methylation of the MLH1 promoter (39%) and increased MSI levels (68%) in samples from gastric cancer patients in comparison to samples from H. pylori-infected adult chronic gastritis patients (P < 0.001 and P < 0.01, respectively). The frequency of promoter methylation for both genes was higher in gastric cancer samples than in H. pylori-positive chronic gastritis samples (P < 0.05). The levels of MLH1 and MGMT mRNA were significantly reduced in chronic gastritis samples that were also hypermethylated (P < 0.01). CONCLUSION: In summary, MGMT and MLH1 methylation did not occur in earlier-stage H. pylori infections and thus might depend on the duration of infection.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Metilación de ADN , Metilasas de Modificación del ADN/genética , Enzimas Reparadoras del ADN/genética , Gastritis/genética , Infecciones por Helicobacter/genética , Helicobacter pylori/aislamiento & purificación , Inestabilidad de Microsatélites , Proteínas Nucleares/genética , Neoplasias Gástricas/genética , Proteínas Supresoras de Tumor/genética , Adolescente , Adulto , Factores de Edad , Anciano , Biopsia , Distribución de Chi-Cuadrado , Niño , Preescolar , Enfermedad Crónica , Femenino , Gastritis/diagnóstico , Gastritis/microbiología , Infecciones por Helicobacter/diagnóstico , Infecciones por Helicobacter/microbiología , Humanos , Masculino , Persona de Mediana Edad , Homólogo 1 de la Proteína MutL , Regiones Promotoras Genéticas , Factores de Riesgo , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/microbiología , Factores de Tiempo , Adulto JovenRESUMEN
A real-time multiplex PCR assay was designed to amplify the virulence genes eae, pEAF, aatA, daaC, elt, est, ipaH, stx(1), and stx(2) for the detection of all diarrheagenic Escherichia coli pathotypes. This assay proved to be more sensitive and rapid than a conventional multiplex PCR for diarrheagenic E. coli isolates from children with diarrhea.
Asunto(s)
Técnicas Bacteriológicas/métodos , Escherichia coli/clasificación , Escherichia coli/aislamiento & purificación , Reacción en Cadena de la Polimerasa Multiplex/métodos , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Niño , Diarrea/diagnóstico , Diarrea/microbiología , Escherichia coli/genética , Infecciones por Escherichia coli/diagnóstico , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/genética , Genotipo , Humanos , Técnicas de Diagnóstico Molecular/métodos , Sensibilidad y Especificidad , Temperatura de Transición , Factores de Virulencia/genéticaRESUMEN
BACKGROUND: Helicobacter pylori ClariRes assay is a novel commercially available real-time PCR assay allowing H. pylori detection and clarithromycin susceptibility testing in either gastric biopsy or stool specimens. OBJECTIVE: The aim of this study was to validate the novel biprobe real-time assay in stool specimens from 217 dyspeptic children. METHODS: DNA from gastric biopsies and stool specimens were obtained and submitted to the biprobe real time assay for H. pylori detection and clarithromycin susceptibility testing. RESULTS: The sensitivity, specificity, and test accuracy were 69, 100 and 93.9% for the detection of H. pylori infection and 83.3, 100 and 95.6%, for detection of clarithromycin resistance. CONCLUSION: This assay proved to be appropriate for H. pylori clarithromycin susceptibility testing, particularly in children populations where a high prevalence of clarithromycin-resistant strains is suspected.
Asunto(s)
Claritromicina/farmacología , Infecciones por Helicobacter/diagnóstico , Infecciones por Helicobacter/microbiología , Helicobacter pylori/efectos de los fármacos , Helicobacter pylori/aislamiento & purificación , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa/métodos , Adolescente , Antibacterianos/farmacología , Brasil , Niño , Preescolar , Heces/microbiología , Femenino , Mucosa Gástrica/microbiología , Helicobacter pylori/genética , Humanos , Lactante , Masculino , Pruebas de Sensibilidad Microbiana/métodos , Sensibilidad y EspecificidadRESUMEN
We isolated 45 Helicobacter pylori strains from 217 child patients. Resistance to clarithromycin, metronidazole, amoxicillin, and tetracycline was detected in 27%, 13%, 4%, and 0% of strains, respectively. The A2143G mutation was the most prevalent (67%) among clarithromycin-resistant strains. In addition, strain genotyping revealed a significant association between gastritis severity and the simultaneous presence of cagA, vacA s1m1, iceA2, and babA2 genes.
Asunto(s)
Antibacterianos/farmacología , Claritromicina/farmacología , Farmacorresistencia Bacteriana , Infecciones por Helicobacter/epidemiología , Helicobacter pylori/clasificación , Helicobacter pylori/efectos de los fármacos , Factores de Virulencia/genética , Adhesinas Bacterianas/genética , Adolescente , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Brasil/epidemiología , Niño , Preescolar , Femenino , Genotipo , Infecciones por Helicobacter/microbiología , Infecciones por Helicobacter/patología , Helicobacter pylori/genética , Helicobacter pylori/aislamiento & purificación , Humanos , Lactante , Masculino , Prevalencia , Índice de Severidad de la EnfermedadRESUMEN
BACKGROUND: We recently observed an association of resistance with a certain enteropathogenic Escherichia coli (EPEC) serotypes and identified a conjugative plasmid, similar to plasmid pED208, that was conserved among archival O111:H2/NM and O119:H2 strains of diverse geographical origin. In this study, we sought to determine the prevalence and distribution of this plasmid among a collection of EPEC isolates from Brazil, as well as to study the susceptibilities of these isolates to antimicrobial agents. RESULTS: Resistance was more commonly seen in typical EPEC than atypical strains. The most prevalent resistances were to ampicillin, tetracycline, streptomycin and the sulfonamides. Markers for the EPEC conjugative multiresistance plasmid, were detected in 21 (30%) of typical but only 4 (5%) of atypical strains (p = 0.001, Chi-squared test). This plasmid, previously reported from only O111 and O119 strains was found in O55 and O127 strains and was associated with the presence of class 1 integrons. CONCLUSION: Our data suggest a limited but expanding host range for the EPEC resistance plasmid.
Asunto(s)
Escherichia coli Enteropatógena/efectos de los fármacos , Escherichia coli Enteropatógena/genética , Infecciones por Escherichia coli/microbiología , Antibacterianos/farmacología , Brasil/epidemiología , Distribución de Chi-Cuadrado , Preescolar , Farmacorresistencia Bacteriana Múltiple , Escherichia coli Enteropatógena/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Genes Bacterianos , Humanos , Pruebas de Sensibilidad Microbiana , Plásmidos/genética , PrevalenciaRESUMEN
Although atypical enteropathogenic Escherichia coli (aEPEC) strains are frequently implicated in childhood diarrhea in developing countries, not much is known about their adherence properties. The phenotypic and genotypic characterization of 29 aEPEC strains expressing the localized adherence-like pattern points toward the involvement of E. coli common pilus (ECP), intimins, and other known E. coli adhesins in this pattern.
Asunto(s)
Adhesinas de Escherichia coli/biosíntesis , Escherichia coli Enteropatógena/patogenicidad , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli/biosíntesis , Hepatocitos/microbiología , Factores de Virulencia/biosíntesis , Adhesinas de Escherichia coli/genética , Técnicas de Tipificación Bacteriana , Línea Celular , Niño , Preescolar , Escherichia coli Enteropatógena/clasificación , Escherichia coli Enteropatógena/genética , Escherichia coli Enteropatógena/aislamiento & purificación , Proteínas de Escherichia coli/genética , Humanos , Serotipificación , Factores de Virulencia/genéticaRESUMEN
We describe the characterization of 126 atypical enteropathogenic Escherichia coli (aEPEC) isolates from 1,749 Brazilian children. Classic aEPEC strains were more frequently found in children with diarrhea than in controls (P < 0.001), showing their importance as acute diarrhea agents in our country. Only aEPEC strains carrying either the ehxA or paa gene were significantly associated with diarrhea.
Asunto(s)
Diarrea/microbiología , Escherichia coli Enteropatógena/clasificación , Escherichia coli Enteropatógena/patogenicidad , Infecciones por Escherichia coli/microbiología , Brasil , Cartilla de ADN/genética , ADN Bacteriano/genética , Proteínas de Escherichia coli/genética , Genotipo , Proteínas Hemolisinas/genética , Humanos , Lactante , Serotipificación , Factores de Virulencia/genéticaRESUMEN
PURPOSE: The aim of this study was to investigate the presence of diarrheagenic Escherichia coli and antibiotic resistance in asymptomatic school-age children living in an area with defective environmental sanitation, comparing with children registered at a private school, both in the city of Osasco, Brazil. METHODS: Seventy-nine school-age children between 5 and 10 years living in a slum and 35 children who attended a private school of the same city were included in the study. RESULTS: DEC was found in 58% of the children living in the slum and in 17% of the control group (P=0.001). Resistance to at least one antimicrobial drug was found in 65% of DEC strains; resistant to two or more antimicrobial drugs was found in 46% of strains. CONCLUSION: The high carriage status among the slum children point towards the widespread environment contamination in low socio-economic housing conditions, in conformance with the pediatric population at higher risk for developing DEC diarrhea.
Asunto(s)
Antibacterianos/uso terapéutico , Diarrea/epidemiología , Farmacorresistencia Bacteriana , Infecciones por Escherichia coli/epidemiología , Escherichia coli/aislamiento & purificación , Áreas de Pobreza , Brasil/epidemiología , Niño , Preescolar , Ciudades , Heces/microbiología , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Población , Prevalencia , Factores de Virulencia/análisisRESUMEN
OBJETIVO: Determinar o número de colônias de lactobacilos e bifidobactérias nas fezes de crianças escolares, pertencentes a dois estratos socioeconômicos. MÉTODOS: Foram analisadas amostras de fezes de crianças com idade entre 6 e 10 anos sem sintomas gastrointestinais ou uso recente de antimicrobianos. O primeiro grupo foi constituído por 86 crianças, moradoras em uma favela localizada no município de Osasco (SP). O segundo grupo foi constituído por 36 crianças matriculadas em uma escola particular da mesma cidade. O estado nutricional foi avaliado usando o índice de massa corporal (IMC) de acordo com os valores de referência do National Center for Health Statistics (NCHS). O isolamento das colônias foi realizado em meios de cultura específicos em anaerobiose, durante 48 e 72 horas a 37 °C. A determinação do número foi feita pelo método da contagem em placa. RESULTADOS: A mediana de lactobacilos (1,125 x 10(9) unidades formadoras de colônia, UFC/g) e bifidobactérias (1,675 x 10(9) UFC/g) na escola particular foi superior (p < 0,001) ao do grupo da favela: 0,250 x 10(9) e 0,350 x 10(9) UFC/g, respectivamente. No grupo da favela, crianças com escore z de IMC < -1,0 desvio padrão (n = 28) apresentaram menor mediana (p < 0,05) de lactobacilos (0,100 x 10(9) UFC/g) e bifidobactérias (0,095 x 10(9) UFC/g) em relação às crianças com IMC > -1,0 desvio padrão (n = 57): 0,350 x 10(9) e 0,420 x 10(9) UFC/g, respectivamente. CONCLUSÃO: A microbiota de crianças escolares que moram em condições ambientais desfavoráveis apresenta menor número de colônias de lactobacilos e bifidobactérias nas fezes, especialmente naquelas com menores valores do IMC.
OBJECTIVE: To determine the number of lactobacillus and bifidobacterium colonies in the feces of schoolchildren from two different socioeconomic levels. METHODS: We analyzed fecal samples of children aged 6 to 10 years without gastrointestinal symptoms or recent use of antimicrobials. The first group included 86 children living in a favela in the city of Osasco, state of São Paulo, southeastern Brazil. The second group included 36 children attending a private school in the same city. Body mass index (BMI) was used to assess nutritional status according to the reference values of the National Center for Health Statistics (NCHS). Specific anaerobic culture media were used for isolation of colonies for 48 and 72 hours at 37 °C. The number of colonies was determined using the plate-counting method. RESULTS: The mean lactobacillus (1.125 x 10(9) colony-forming units, CFU/g) and bifidobacterium (1.675 x 10(9) CFU/g) counts in the private school group were higher (p < 0.001) than those in the favela group: 0.250 x 10(9) and 0.350 x 10(9) CFU/g, respectively. In the favela group, children with BMI z score < -1.0 standard deviation (SD) (n = 28) showed lower mean (p < 0.05) lactobacillus (0.100 x 10(9) CFU/g) and bifidobacterium (0.095 x 10(9) CFU/g) counts than the children with BMI > -1.0 SD (n = 57): 0.350 x 10(9) and 0.420 x 10(9) CFU/g, respectively. CONCLUSION: The microbiota of schoolchildren living in unfavorable environmental conditions shows lower numbers of fecal lactobacillus and bifidobacterium colonies, especially in children with lower BMI values.
Asunto(s)
Niño , Femenino , Humanos , Masculino , Bifidobacterium/aislamiento & purificación , Heces/microbiología , Lactobacillus/aislamiento & purificación , Clase Social , Índice de Masa Corporal , Tamaño Corporal , Brasil , Distribución de Chi-Cuadrado , Recuento de Colonia Microbiana , Estudios Transversales , Escherichia coli/aislamiento & purificación , Áreas de Pobreza , Sector Privado , Instituciones AcadémicasRESUMEN
OBJECTIVE: To determine the number of lactobacillus and bifidobacterium colonies in the feces of schoolchildren from two different socioeconomic levels. METHODS: We analyzed fecal samples of children aged 6 to 10 years without gastrointestinal symptoms or recent use of antimicrobials. The first group included 86 children living in a favela in the city of Osasco, state of São Paulo, southeastern Brazil. The second group included 36 children attending a private school in the same city. Body mass index (BMI) was used to assess nutritional status according to the reference values of the National Center for Health Statistics (NCHS). Specific anaerobic culture media were used for isolation of colonies for 48 and 72 hours at 37 degrees C. The number of colonies was determined using the plate-counting method. RESULTS: The mean lactobacillus (1.125 x 10(9) colony-forming units, CFU/g) and bifidobacterium (1.675 x 10(9) CFU/g) counts in the private school group were higher (p < 0.001) than those in the favela group: 0.250 x 10(9) and 0.350 x 10(9) CFU/g, respectively. In the favela group, children with BMI z score < -1.0 standard deviation (SD) (n = 28) showed lower mean (p < 0.05) lactobacillus (0.100 x 10(9) CFU/g) and bifidobacterium (0.095 x 10(9) CFU/g) counts than the children with BMI >or= -1.0 SD (n = 57): 0.350 x 10(9) and 0.420 x 10(9) CFU/g, respectively. CONCLUSION: The microbiota of schoolchildren living in unfavorable environmental conditions shows lower numbers of fecal lactobacillus and bifidobacterium colonies, especially in children with lower BMI values.
Asunto(s)
Bifidobacterium/aislamiento & purificación , Heces/microbiología , Lactobacillus/aislamiento & purificación , Clase Social , Índice de Masa Corporal , Tamaño Corporal , Brasil , Distribución de Chi-Cuadrado , Niño , Recuento de Colonia Microbiana , Estudios Transversales , Escherichia coli/aislamiento & purificación , Femenino , Humanos , Masculino , Áreas de Pobreza , Sector Privado , Instituciones AcadémicasRESUMEN
In a prospective study between February 2003 and June 2004, stool specimens of children less than 2 years of age with diarrhoea (n=218) and without diarrhoea (n=86), living in Vitória, Espírito Santo, Brazil, were examined for the presence of diarrhoeagenic Escherichia coli. E. coli isolates were tested by colony blot hybridization with specific DNA probes designed to detect EPEC, ETEC, EIEC, EAEC, DAEC and EHEC/STEC. Diarrhoeagenic E. coli strains were detected as the sole pathogen in stools of 92 (30.3 %) children, including 72 (33.0 %) with diarrhoea and 20 (23.2 %) without diarrhoea. DAEC was the most frequent pathotype and was found significantly more often from patients (18.3 %) than from controls (8.1 %) (P<0.05), particularly among children more than 1 year of age (P=0.01). Atypical EPEC and EAEC isolates were isolated from both patients (5.5 % and 4.6 %, respectively) and controls (6.9 % and 6.9 %, respectively). ETEC was more frequently isolated from patients (3.2 %) than controls (1.2 %). Typical EPEC (0.9 %) and EIEC (0.4 %) isolates were detected only in children with diarrhoea. In conclusion, our data suggest that DAEC should be considered potential pathogens in the region of Brazil studied.