RESUMEN
The microbiota of the Amazon River basin has been little studied. We compared the structure of bacterial communities of the Solimões and Negro Rivers, the main Amazon River tributaries, based on analysis of 16S rRNA gene sequences. Water was sampled with a 3-L Van Dorn collection bottle; samples were collected at nine different points/depths totaling 27 L of water from each river. Total DNA was extracted from biomass retained by a 0.22-µm filter after sequential filtration of the water through 0.8- and 0.22-µm filters. The 16S rRNA gene was amplified by PCR, cloned and sequenced, and the sequences were analyzed with the PHYLIP and DOTUR programs to obtain the operational taxonomic units (OTUs) and to calculate the diversity and richness indices using the SPADE program. Taxonomic affiliation was determined using the naive Bayesian rRNA Classifier of the RDP II (Ribosomal Database Project). We recovered 158 sequences from the Solimões River grouped into 103 OTUs, and 197 sequences from the Negro River library grouped into 90 OTUs by the DOTUR program. The Solimões River was found to have a greater diversity of bacterial genera, and greater estimated richness of 446 OTUs, compared with 242 OTUs from the Negro River, as calculated by ACE estimator. The Negro River has less bacterial diversity, but more 16S rRNA gene sequences belonging to the bacterial genus Polynucleobacter were detected; 56 sequences from this genus were found (about 30% of the total sequences). We suggest that a more in-depth investigation be made to elucidate the role played by these bacteria in the river environment. These differences in bacterial diversity between Solimões and Negro Rivers could be explained by differences in organic matter content and pH of the rivers.
Asunto(s)
Bacterias/genética , Genes Bacterianos/genética , Genes de ARNr/genética , ARN Ribosómico/genética , Subunidades Ribosómicas Pequeñas Bacterianas/genética , Ríos/microbiología , Bacterias/clasificación , Secuencia de Bases , Brasil , Biblioteca de GenesRESUMEN
Feces of 70 diarrhoeic and 230 non-diarrhoeic domestic cats from Sao Paulo, Brazil were investigated for enteropathogenic (EPEC), enterohaemorrhagic (EHEC) and enterotoxigenic (ETEC) Escherichia coli types. While ETEC and EHEC strains were not found, 15 EPEC strains were isolated from 14 cats, of which 13 were non-diarrhoeic, and one diarrhoeic. None of 15 EPEC strains carried the bfpA gene or the EPEC adherence factor plasmid, indicating atypical EPEC types. The EPEC strains were heterogeneous with regard to intimin types, such as eae-theta (three strains), eae-kappa (n = 3), eae-alpha1 (n = 2), eae-iota (n = 2), one eae-alpha2, eae-beta1 and eae-eta each, and two were not typeable. The majority of the EPEC isolates adhered to HEp-2 cells in a localized adherence-like pattern and were positive for fluorescence actin staining. The EPEC strains belonged to 12 different serotypes, including O111:H25 and O125:H6, which are known to be pathogens in humans. Multi locus sequence typing revealed a close genetic similarity between the O111:H25 and O125:H6 strains from cats, dogs and humans. Our results show that domestic cats are colonized by EPEC, including serotypes previously described as human pathogens. As these EPEC strains are also isolated from humans, a cycle of mutual infection by EPEC between cats and its households cannot be ruled out, though the transmission dynamics among the reservoirs are not yet understood clearly.
Asunto(s)
Enfermedades de los Gatos/microbiología , Reservorios de Enfermedades/veterinaria , Escherichia coli Enteropatógena/aislamiento & purificación , Adhesinas Bacterianas/genética , Animales , Brasil , Gatos , Diarrea/microbiología , Diarrea/veterinaria , Escherichia coli Enteropatógena/genética , Proteínas de Escherichia coli/genética , Heces/microbiología , Humanos , FilogeniaRESUMEN
Shiga toxin-producing Escherichia coli (STEC), is the most important recently emerged group of foodborne pathogens. Ruminants, especially cattle, have been implicated as a principal reservoir of STEC, undercooked ground beef and raw milk being the major vehicles of foodborne outbreaks. Enteropathogenic E. coli (EPEC) strains are defined as eae-harboring diarrheagenic E. coli that possess the ability to form A/E lesions on intestinal cells and that do not possess Shiga toxin genes. In order to determine the occurrence, serotypes and virulence markers of STEC and EPEC strains, 546 fecal samples from 264 diarrheic calves and 282 healthy calves in beef farms in São Paulo, Brazil, were screened by PCR. STEC and EPEC were isolated in 10% and 2.7% of the 546 animals, respectively. Although IMS test was used, the STEC serotype O157:H7 was not detected. The most frequent serotypes among STEC strains were O7:H10, O22:H16, O111:H(-), O119:H(-) and O174:H21, whereas O26:H11, O123:H11 and O177:H11 were the most prevalent among EPEC strains. In this study, serotypes not previously reported were found among STEC strains: O7:H7, O7:H10, O48:H7, O111:H19, O123:H2, O132:H51, O173:H(-), and O175:H49. The eae gene was detected in 25% of the STEC and 100% of EPEC strains. The intimin type theta/gamma2 was the most frequent among STEC, whereas the intimin beta1 was the most frequent intimin type among EPEC strains. To our knowledge, this is the first report of the occurrence of the new intimin muB in one strain of animal origin. This new intimin was detected in one atypical EPEC strain of serotype O123:H? isolated from diarrheic cattle. The enterohemolysin (ehxA) was detected in 51% of the STEC and 80% of the EPEC strains, whereas STEC autoagglutinating adhesin (saa) virulence gene was detected only in those STEC strains negative for eae gene. All 15 bovine EPEC strains isolated in this study were negative for both eaf and bfp genes. Our data shows that in Brazil cattle are not only a reservoir of STEC and atypical EPEC, but also a potential source of infection in humans, since the important STEC serotypes previously described and associated with severe diseases in humans, such as O111:H(-), O113:H21, O118:H16, and O174:H21 were isolated.
Asunto(s)
Enfermedades de los Bovinos/microbiología , Infecciones por Escherichia coli/veterinaria , Escherichia coli/clasificación , Escherichia coli/patogenicidad , Toxinas Shiga/biosíntesis , Adhesinas Bacterianas/genética , Animales , Brasil , Bovinos , Enfermedades de los Bovinos/epidemiología , Reservorios de Enfermedades/veterinaria , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Proteínas de Escherichia coli , Heces/microbiología , Humanos , Carne/microbiología , Filogenia , Reacción en Cadena de la Polimerasa , Serotipificación , Virulencia/genéticaRESUMEN
The occurrence of Shiga toxin (Stx) gene sequences was examined in 344 fecal samples from diarrheic (n=139) and non-diarrheic (n=205) calves from 12 beef farms in São Paulo State, Brazil to study the prevalence of Shiga toxin-producing Escherichia coli (STEC) strains. Forty-four (12.7%) animals were found to be positive for stx. The frequency of carriage of stx was higher in diarrheic calves (28/139, 20%) than in non-diarrheic animals (16/205, 7.8%) (P<0.001). Among the 24 STEC strains recovered from the animals, 12 isolates carried stx1, four stx2, and 8 carried both stx1 and stx2 genes. The eae and the enterohaemolysin (Ehly) gene sequences occurred at high frequencies in these STEC strains (41.6 and 50.0%, respectively). A total of 16 serotypes were identified. The serotypes O111:NM (four isolates), O111:H8 (two) and O118:H16 (one), currently described as enterohaemorrhagic E. coli (EHEC), were isolated from cattle in Brazil for the first time. These findings reinforce the importance of cattle as a reservoir of EHEC strains in Brazil.
Asunto(s)
Enfermedades de los Bovinos/microbiología , Infecciones por Escherichia coli/veterinaria , Proteínas de Escherichia coli , Escherichia coli/aislamiento & purificación , Toxinas Shiga/biosíntesis , Animales , Antígenos Bacterianos/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/metabolismo , Brasil/epidemiología , Bovinos , Enfermedades de los Bovinos/epidemiología , Chlorocebus aethiops , Pruebas Inmunológicas de Citotoxicidad , ADN Bacteriano/química , ADN Bacteriano/genética , Diarrea/microbiología , Diarrea/veterinaria , Escherichia coli/genética , Escherichia coli/metabolismo , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Antígenos O/metabolismo , Reacción en Cadena de la Polimerasa , Prevalencia , Toxinas Shiga/genética , Células VeroRESUMEN
Fecal samples from 48 sheep from two farms in São Paulo, SP, Brazil, were examined to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC). Forty-two STEC strains were isolated from 25 (52.1%) of 48 sheep feces, and were examined for the presence of genes encoding STEC-related virulence factors. Twenty-one (50.0%) of the 42 STEC isolates were positive for stx(1) and stx(2), 16 isolates (38.1%) were stx(1), and five (11.9%) were stx(2). Expression of Shiga toxins was demonstrated by the Vero cell toxicity test for all the strains carrying stx. Fourteen of the STEC strains (33.3%) carried the enterohemolysin gene (ehly) and presented the enterohemolytic phenotype, and five (11.9%) were positive for the plasmid encoded katP gene. The eae gene was not present in any of the isolates. STEC strains presenting stx(1), stx(2) and ehly were most commonly (23.8%) recovered from these sheep. The predominant STEC serotype found was ONT:H8, and others included O5:H-, O16:H-, O75:H-, O75:H8, O87:H16, O91:H-, O146:H21, O172:H-, OR:H-, ONT:H- and ONT:H16. This is the first report on ovine STEC in South America, and identifies a number of ovine non-O157 STEC that belong to serotypes implicated in human disease.
Asunto(s)
Infecciones por Escherichia coli/veterinaria , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Enfermedades de las Ovejas/microbiología , Toxinas Shiga/metabolismo , Animales , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Brasil , Chlorocebus aethiops , ADN Bacteriano/química , ADN Bacteriano/genética , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Infecciones por Escherichia coli/microbiología , Heces/microbiología , Antígenos O/genética , Antígenos O/metabolismo , Reacción en Cadena de la Polimerasa/veterinaria , Serotipificación , Ovinos , Toxinas Shiga/genética , Células VeroRESUMEN
This study investigated the antibacterial activity of propolis produced by A. mellifera and Brazilian stingless bees, called "meliponíneos". Susceptibility tests to ethanolic extracts of propolis (EEP) were performed using bacterial strains (Staphylococcus aureus, Enterococcus sp, and Escherichia coli) isolated from human infections. Dilution of EEP in agar (per cent v/v) was used for determination of minimal inhibitory concentration (MIC). The stingless bee species (and common names) were: Nannotrigona testaceicornis ("Irai"), Tetragonisca angustula ("Jataí"), Trigona spinipes ("Arapuá"), Scaptotrigona sp ("Tiúba"), Partamona sp ("Cupira"), Melipona scutellaris ("Uruçu"), Melipona sp ("Manduri"), and Melipona mandaçaia ("Mandaçaia"). EEP inhibitory efficiencies according to bacterial strains were: S. aureus - "Cupira" > "Manduri" = A. mellifera > "Uruçu" > "Mandaçaia" > "Iraí" > "Tiúba" > "Jataí" > "Arapuá" = Ethanol; Enterococcus sp - "Cupira" > "Manduri" > A. mellifera > "Mandaçaia" > "Uruçu" > "Tiúba" > "Jataí" > "Arapuá" = Ethanol; E. coli - "Manduri" > "Jataí" > Ethanol > A.mellifera > "Uruçu" > "Cupira" > "Iraí". Propolis produced by "Cupira" and "Manduri" bees showed higher antibacterial activity than A. mellifera.