RESUMEN

Aquatic systems have traditionally played a key role in the development of human life, providing multiple ecosystem services to society and being a reservoir for a wide biodiversity of organisms. Among them, bacteria belonging to Legionella stand out, mainly because they are of great interest both in the field of microbial ecology and public health, since some of them turn out to be pathogenic for humans. The aim of this work was to study the monthly temporal dynamics of Legionella spp. and its relationship with the environmental variables measured in two Pampean shallow lakes (Gómez and Carpincho, Buenos Aires Province, Argentina). The analysis was carried out using a quantitative approach by real-time polymerase chain reaction (qPCR) and a non-quantitative approach using bacterial diversity data obtained by next-generation sequencing (NGS), using the Illumina MiSeq platform. Our results showed that the overall Legionella abundance was very high in the studied Pampean shallow lakes. Notably, fluctuations in dissolved organic carbon and temperature influenced the dynamics shifts in Legionella abundances. Correlation analyses between Legionella reads from NGS and copy numbers obtained through qPCR revealed positive relationships, unveiling distinctions attributable to the diverse sequence processing algorithms employed in the analysis of NGS data.

Asunto(s)

RESUMEN

Modern microbial mats are relictual communities mostly found in extreme environments worldwide. Despite their significance as representatives of the ancestral Earth and their important roles in biogeochemical cycling, research on microbial mats has largely been localized, focusing on site-specific descriptions and environmental change experiments. Here, we present a global comparative analysis of non-lithifying microbial mats, integrating environmental measurements with metagenomic data from 62 samples across eight sites, including two new samples from the recently discovered Archaean Domes from Cuatro Ciénegas, Mexico. Our results revealed a notable influence of environmental filtering on both taxonomic and functional compositions of microbial mats. Functional redundancy appears to confer resilience to mats, with essential metabolic pathways conserved across diverse and highly contrasting habitats. We identified six highly correlated clusters of taxa performing similar ecological functions, suggesting niche partitioning and functional specialization as key mechanisms shaping community structure. Our findings provide insights into the ecological principles governing microbial mats, and lay the foundation for future research elucidating the intricate interplay between environmental factors and microbial community dynamics.

Asunto(s)

RESUMEN

Polymerase chain reaction (PCR) assays targeting 16S rRNA genes followed by DNA sequencing are still important tools to characterize microbial communities present in environmental samples. However, despite the crescent number of deposited archaeal DNA sequences in databases, until now we do not have a clear picture of the effectiveness and specificity of the universal primers widely used to describe archaeal communities from different natural habitats. Therefore, in this study, we compared the phylogenetic profile obtained when Cerrado lake sediment DNA samples were submitted to 16S rDNA PCR employing three Archaea-specific primer sets commonly used. Our findings reveal that specificity of primers differed depending on the source of the analyzed DNA. Furthermore, archaeal communities revealed by each primer pair varied greatly, indicating that 16S rRNA gene primer choice affects the community profile obtained, with differences in both taxon detection and operational taxonomic unit (OTU) estimates.(AU)

A amplificação de genes que codificam o rRNA 16S por reação em cadeia da polimerase (PCR) e o seu sub sequentesequenciamento consistem em uma ferramenta importante na caracterização de comunidades microbianas presentes em amostras ambientais. No entanto, apesar do crescente número de sequências de DNA de Archaea depositadas em bancos de dados, a especificidade e efetividade dos iniciadores de PCR descritos como universais e amplamente utilizados na descrição desse grupo ainda não está clara. Neste estudo foram comparados os perfis filogenéticos de comunidades de arqueias obtidos a partir amostras de DNA de sedimentos lacustres do Cerrado submetidas a ensaios de PCR empregando três pares de iniciadores específicos para Archaea, comumente utilizados neste tipo de estudo. Nossos resultados indicam que as comunidades de arqueias detectadas com cada par de iniciadores apresentaram grande variação filogenética, sugerindo que a escolha de iniciadores dirigidos ao gene de rRNA 16S tem efeito significativo no perfil da comunidade descrita, com diferenças tanto em relação aos táxons detectados, como nas estimativas de unidades taxonômicas operacionais (OTU).(AU)

Asunto(s)

RESUMEN

Abstract Polymerase chain reaction (PCR) assays targeting 16S rRNA genes followed by DNA sequencing are still important tools to characterize microbial communities present in environmental samples. However, despite the crescent number of deposited archaeal DNA sequences in databases, until now we do not have a clear picture of the effectiveness and specificity of the universal primers widely used to describe archaeal communities from different natural habitats. Therefore, in this study, we compared the phylogenetic profile obtained when Cerrado lake sediment DNA samples were submitted to 16S rDNA PCR employing three Archaea-specific primer sets commonly used. Our findings reveal that specificity of primers differed depending on the source of the analyzed DNA. Furthermore, archaeal communities revealed by each primer pair varied greatly, indicating that 16S rRNA gene primer choice affects the community profile obtained, with differences in both taxon detection and operational taxonomic unit (OTU) estimates.

Resumo A amplificação de genes que codificam o rRNA 16S por reação em cadeia da polimerase (PCR) e o seu subsequente sequenciamento consistem em uma ferramenta importante na caracterização de comunidades microbianas presentes em amostras ambientais. No entanto, apesar do crescente número de sequências de DNA de Archaea depositadas em bancos de dados, a especificidade e efetividade dos iniciadores de PCR descritos como universais e amplamente utilizados na descrição desse grupo ainda não está clara. Neste estudo foram comparados os perfis filogenéticos de comunidades de arqueias obtidos a partir amostras de DNA de sedimentos lacustres do Cerrado submetidas a ensaios de PCR empregando três pares de iniciadores específicos para Archaea, comumente utilizados neste tipo de estudo. Nossos resultados indicam que as comunidades de arqueias detectadas com cada par de iniciadores apresentaram grande variação filogenética, sugerindo que a escolha de iniciadores dirigidos ao gene de rRNA 16S tem efeito significativo no perfil da comunidade descrita, com diferenças tanto em relação aos táxons detectados, como nas estimativas de unidades taxonômicas operacionais (OTU).

Asunto(s)

RESUMEN

Polymerase chain reaction (PCR) assays targeting 16S rRNA genes followed by DNA sequencing are still important tools to characterize microbial communities present in environmental samples. However, despite the crescent number of deposited archaeal DNA sequences in databases, until now we do not have a clear picture of the effectiveness and specificity of the universal primers widely used to describe archaeal communities from different natural habitats. Therefore, in this study, we compared the phylogenetic profile obtained when Cerrado lake sediment DNA samples were submitted to 16S rDNA PCR employing three Archaea-specific primer sets commonly used. Our findings reveal that specificity of primers differed depending on the source of the analyzed DNA. Furthermore, archaeal communities revealed by each primer pair varied greatly, indicating that 16S rRNA gene primer choice affects the community profile obtained, with differences in both taxon detection and operational taxonomic unit (OTU) estimates.

A amplificação de genes que codificam o rRNA 16S por reação em cadeia da polimerase (PCR) e o seu sub sequentesequenciamento consistem em uma ferramenta importante na caracterização de comunidades microbianas presentes em amostras ambientais. No entanto, apesar do crescente número de sequências de DNA de Archaea depositadas em bancos de dados, a especificidade e efetividade dos iniciadores de PCR descritos como universais e amplamente utilizados na descrição desse grupo ainda não está clara. Neste estudo foram comparados os perfis filogenéticos de comunidades de arqueias obtidos a partir amostras de DNA de sedimentos lacustres do Cerrado submetidas a ensaios de PCR empregando três pares de iniciadores específicos para Archaea, comumente utilizados neste tipo de estudo. Nossos resultados indicam que as comunidades de arqueias detectadas com cada par de iniciadores apresentaram grande variação filogenética, sugerindo que a escolha de iniciadores dirigidos ao gene de rRNA 16S tem efeito significativo no perfil da comunidade descrita, com diferenças tanto em relação aos táxons detectados, como nas estimativas de unidades taxonômicas operacionais (OTU).

Asunto(s)

RESUMEN

Abstract Polymerase chain reaction (PCR) assays targeting 16S rRNA genes followed by DNA sequencing are still important tools to characterize microbial communities present in environmental samples. However, despite the crescent number of deposited archaeal DNA sequences in databases, until now we do not have a clear picture of the effectiveness and specificity of the universal primers widely used to describe archaeal communities from different natural habitats. Therefore, in this study, we compared the phylogenetic profile obtained when Cerrado lake sediment DNA samples were submitted to 16S rDNA PCR employing three Archaea-specific primer sets commonly used. Our findings reveal that specificity of primers differed depending on the source of the analyzed DNA. Furthermore, archaeal communities revealed by each primer pair varied greatly, indicating that 16S rRNA gene primer choice affects the community profile obtained, with differences in both taxon detection and operational taxonomic unit (OTU) estimates.

Resumo A amplificação de genes que codificam o rRNA 16S por reação em cadeia da polimerase (PCR) e o seu subsequente sequenciamento consistem em uma ferramenta importante na caracterização de comunidades microbianas presentes em amostras ambientais. No entanto, apesar do crescente número de sequências de DNA de Archaea depositadas em bancos de dados, a especificidade e efetividade dos iniciadores de PCR descritos como universais e amplamente utilizados na descrição desse grupo ainda não está clara. Neste estudo foram comparados os perfis filogenéticos de comunidades de arqueias obtidos a partir amostras de DNA de sedimentos lacustres do Cerrado submetidas a ensaios de PCR empregando três pares de iniciadores específicos para Archaea, comumente utilizados neste tipo de estudo. Nossos resultados indicam que as comunidades de arqueias detectadas com cada par de iniciadores apresentaram grande variação filogenética, sugerindo que a escolha de iniciadores dirigidos ao gene de rRNA 16S tem efeito significativo no perfil da comunidade descrita, com diferenças tanto em relação aos táxons detectados, como nas estimativas de unidades taxonômicas operacionais (OTU).

RESUMEN

Salmonella enterica is a leading cause of human gastrointestinal disease worldwide. Given that Salmonella is persistent in aquatic environments, this study examined the prevalence, levels and genotypic diversity of Salmonella isolates recovered from major rivers in an important agricultural region in northwestern Mexico. During a 13-month period, a total of 143 river water samples were collected and subjected to size-exclusion ultrafiltration, followed by enrichment, and selective media for Salmonella isolation and quantitation. The recovered Salmonella isolates were examined by next-generation sequencing for genome characterization. Salmonella prevalence in river water was lower in the winter months (0.65 MPN/100 mL) and significantly higher in the summer months (13.98 MPN/100 mL), and a Poisson regression model indicated a negative effect of pH and salinity and a positive effect of river water temperature (p = 0.00) on Salmonella levels. Molecular subtyping revealed Oranienburg, Anatum and Saintpaul were the most predominant Salmonella serovars. Single nucleotide polymorphism (SNP)-based phylogeny revealed that the detected 27 distinct serovars from river water clustered in two major clades. Multiple nonsynonymous SNPs were detected in stiA, sivH, and ratA, genes required for Salmonella fitness and survival, and these findings identified relevant markers to potentially develop improved methods for characterizing this pathogen.

RESUMEN

Objetive: Evaluate an Ozone Generating System (OGS) through of the microorganisms count and identificated in the air of the sanitary environments of the National Institute of Health (INS) from Peru. These were The study:exposed to OGS for 1 min per m2, air samples were collected at volumes of 200L, 500Land 1000Lby impaction, pre and post exposure to OGS, cultures were obtained on Plate Count Agar (PCA) and Oxytetracycline Glucose Agar (OGA) grown at 35°C±2°C for 48 hours and 25°C ± 2°C for 5 days.Adecrease Findings:in the count of fungi after exposure to OGS, the difference being statistically significant for the volumes of 200L(p=0.047) and 1000 L(p<0.005); Aspergillus spp. species were identified in most cultures, in bacteria no significant difference was observed.The OGS is a method that inhibits the Conclusions:growth of most fungi in sanitary environments.

Objetivo: Evaluar un Sistema Generador de Ozono (SGO) a través del recuento e identificación de microorganismos en el aire de los ambientes sanitarios del Instituto Nacional de Salud (INS) del Perú. El estudio: Los ambientes fueron expuestos a SGO por 1 min por m2, se recolectaron muestras de aire en volúmenes de 200L, 500L y 1000L por impactación, pre y post exposición a SGO; los cultivos se obtuvieron en Plate Count Agar (PCA) y Oxitetracicline Glucose Agar (OGA) cultivados a 35 °C ± 2 °C durante 48 horas y 25 °C ± 2 °C durante 5 días. Hallazgos: Disminución del recuento de hongos post exposición a SGO, la diferencia fue estadísticamente significativa para los volúmenes de 200L (p=0.047) y 1000 L (p<0.005); especies de Aspergillus spp. fueron identificados en la mayoría de los cultivos; en bacterias no se observaron diferencias significativas. Conclusiones: El SGO es un método que inhibe el crecimiento de la mayoría de hongos en ambientes sanitarios.

RESUMEN

Resumen Objetivo: describir el perfil microbiológico de las superficies inanimadas en contacto con el paciente en un hospital nivel III de la seguridad social de Chiclayo, Perú. Material y métodos: Se realizó un estudio transversal, con los datos de los informes del Control microbiológico cualitativo de ambientes físicos de 5 servicios de un Hospital de Chiclayo nivel III del Perú. El método para la identificación de microorganismos fue el sistema automatizado VITEK MS. Se presentan análisis des criptivos como frecuencias y porcentajes. Resultados: Se reportaron un total de 177 aislamientos, de los cuales 97,74% (173) fueron positivos, de estos, el 50,87% (88) estuvo conformado por bacilos gram negativos, siendo el microorganismo más aislado Acinetobacter baumannii (17 muestras) seguido de Rhizobium radiobacter (16) y Sphingomonas paucimobilis 13. Conclusiones: El ambiente hospitalario se encuentra altamente contaminado, siendo la mayoría microorganismos patógenos. Estos resultados guardarían relación con el prolongado tiempo de vida de los microorganismos en las superficies inertes y el proceso de limpieza y desinfección del ambiente hospitalario, por lo que la evaluación de su eficacia y el posible desarrollo de nuevas y mejores técnicas de limpieza deben ser motivo de investigación.

Abstract Objective: to describe the microbiological profile of inanimate surfaces in contact with the patient in a social security level III hospital in Chiclayo, Peru. Material and methods: An observational, descriptive, transversal study was carried out with the data from the reports of the Microbiological Qualitative Control of Physical Environments of 5 services of a Chiclayo Hospital level III in Peru. The method for the identification of microorganisms was the automated system VITEK MS. Descriptive analyses such as frequencies and percentages are presented. Results: A total of 177 isolations were reported, from which 97.74% (173) were positive, of these, 50.87% (88) were composed by gram-negative bacilli, being the most isolated microorganism Acinetobacter baumannii (17 samples) followed by Rhizobium radiobacter (16) and Sphingomonas paucimobilis 13. Conclusions: The hospital environment is highly contaminated, being most of them pathogenic microorganisms. These results would be related to the long life of microorganisms on inert surfaces and the process of cleaning and disinfection of the hospital environment, so the evaluation of its effectiveness and the possible development of new and better cleaning techniques should be investigated.

RESUMEN

Background and Objectives: This study aimed to identify the presence of microorganisms in the aesthetic environment and assess professionals' knowledge about relevant infection prevention measures, considering the importance of the issue and the lack of study in the area. Methods: A total of 100 clinics that perform minimally invasive aesthetic procedures in Porto Alegre (RS), Brazil, were visited. Procedures such as botulin-toxin, dermal fillers, collagen biostimulators, thread lift, chemical peels and laser hair removal were considered. A questionnaire about infection prevention measures were answered by 50 professionals. Also, 100 samples were collected from the environment for bacterial identification and antimicrobial susceptibility testing. Results: There was an infection prevention protocol in 40% of clinics, in which 95% of respondents had complete college education. Periodic professional training regarding infection control measures were performed in 72% of clinics. An autoclave was used for sterilization of materials and instruments in 66% of clinics. From the samples collected, 85% showed bacterial growth by microbiological methods. Coagulase-negative Staphylococci was the most prevalent genera found, and 16% of them were resistant to both cefoxitin, erythromycin, and clindamycin. Four isolates were positive for mecA by PCR. Conclusion: The presence of well-trained professionals is critical in aesthetic clinics so that biosafety and infection prevention measures are taken.(AU)

Justificativa e Objetivos: Este estudo teve como objetivo identificar a presença de microrganismos no ambiente estético e avaliar o conhecimento dos profissionais sobre medidas relevantes de prevenção de infecções, considerando a importância do tema e a falta de estudos nesta área. Métodos: Foram visitadas 100 clínicas que realizam procedimentos estéticos minimamente invasivos em Porto Alegre (RS), Brasil. Foram considerados procedimentos injetáveis como aplicação de toxina botulínica, preenchedores faciais, microagulhamento, bioestimuladores de colágeno, fios de sustentação, peelings químicos e depilação a laser. Um questionário sobre medidas de prevenção de infecção foi respondido por 50 profissionais. Além disso, 100 amostras foram coletadas do ambiente para identificação bacteriana e teste de sensibilidade aos antimicrobianos. Resultados: Existia protocolo de prevenção de infecção em 40% dos ambulatórios, no qual 95% dos profissionais entrevistados possuíam ensino superior completo. Treinamento profissional periódico sobre medidas de controle de infecção foi realizado em 72% dos ambulatórios. Autoclave foi utilizada para esterilização de materiais e instrumentais em 66% das clínicas. Das amostras coletadas, 85% apresentaram crescimento bacteriano nas culturas microbiológicas. Staphylococci coagulase-negativo foi o gênero mais prevalente encontrado; e 16% deles eram resistentes à cefoxitina, eritromicina e clindamicina. Quatro isolados foram positivos para mecA por PCR. Conclusão: A presença de profissionais devidamente treinados é fundamental nas clínicas de estética, para que medidas de biossegurança e prevenção de infecções sejam tomadas.(AU)

Justificación y Objetivos: Este estudio tuvo como objetivo identificar la presencia de microorganismos en el entorno estético y evaluar el conocimiento de los profesionales sobre las medidas de prevención de infecciones relevantes, considerando la importancia del tema y la falta de estudios en esta área. Métodos: Se visitaron 100 clínicas que realizan procedimientos estéticos mínimamente invasivos en Porto Alegre (RS), Brasil. Se consideraron procedimientos invasivos, como la aplicación de toxina botulínica, rellenos faciales, microagujas, bioestimuladores de colágeno, hilos de soporte, peelings químicos y depilación láser. Un cuestionario sobre medidas de prevención de infecciones fue respondido por 50 profesionales. Además, se recolectaron 100 muestras del medio ambiente para la identificación bacteriana y las pruebas de susceptibilidad a los antimicrobianos. Resultados: Existía un protocolo de prevención de infecciones en el 40% de las clínicas, en el que el 95% de los profesionales encuestados tenía educación universitaria completa. En el 72% de las clínicas se realizó capacitación profesional periódica sobre medidas de control de infecciones. Se utilizó un autoclave para la esterilización de materiales e instrumentos en el 66% de las clínicas. De las muestras recolectadas, el 85% mostró crecimiento bacteriano por métodos de cultivo microbiologicos. El Staphylococci coagulasa negativo fue el género más prevalente encontrado, y el 16% de ellos eran resistentes tanto a cefoxitina, eritromicina y clindamicina. Cuatro aislamientos fueron positivos para mecA por PCR. Conclusión: La presencia de profesionales debidamente capacitados es fundamental en las clínicas de estética, para la toma medidas de bioseguridad y prevención de infecciones.(AU)

Asunto(s)

RESUMEN

The composition of tick microbiomes varies both within and among tick species. Whether this variation is intrinsic (related to tick characteristics) or extrinsic (related to vertebrate host and habitat) is poorly understood but important, as microbiota can influence the reproductive success and vector competence of ticks. We aimed to uncover what intrinsic and extrinsic factors best explain the microbial composition and taxon richness of 11 species of neotropical ticks collected from eight species of small mammals in 18 forest fragments across central Panama. Microbial richness varied among tick species, life stages, and collection sites but was not related to host blood source. Microbiome composition was best explained by tick life stage, with bacterial assemblages of larvae being a subset of those of nymphs. Collection site explained most of the bacterial taxa with differential abundance across intrinsic and extrinsic factors. Francisella and Rickettsia were highly prevalent, but their proportional abundance differed greatly among tick species, and we found both positive and negative cooccurrence between members of these two genera. Other tick endosymbionts (e.g., Coxiella and Rickettsiella) were associated with specific tick species. In addition, we detected Anaplasma and Bartonella in several tick species. Our results indicate that the microbial composition and richness of neotropical ticks are principally related to intrinsic factors (tick species and life stage) and collection site. Taken together, our analysis informs how tick microbiomes are structured and can help anchor our understanding of tick microbiomes from tropical environments more broadly.IMPORTANCE Blood-feeding arthropod microbiomes often play important roles in disease transmission, yet the factors that structure tick microbial communities in the Neotropics are unknown. Utilizing ticks collected from live animals in neotropical forest fragments, this study teases apart the contributions of intrinsic and extrinsic tick-associated factors on tick microbial composition as well as which specific microbes contribute to differences across tick species, tick life stages, the mammals they fed on, and the locations from where they were sampled. Furthermore, this study provides revelations of how notable tick-associated bacterial genera are interacting with other tick-associated microbes as well as the forest animals they encounter.

Asunto(s)

RESUMEN

Environmental pollution by plastic debris is estimated on a scale of 100 million metric tons, a portion of which is fragmented into micro- and nanoplastics. These fragments are often colonized by bacterial species in marine environments, possibly contributing to the biodegradation of such materials. However, further investigations are necessary to determine the impact of abiotic polymer weathering on biofilm adhesion, as well as the specific biofilm formation strategies employed by marine isolates. Here, we evaluate deep-sea sediment bacterial isolates for biofilm adhesion, extracellular matrix production, and polymer degradation ability. Our study focuses on high-density polyethylene (HDPE) fragments for their high durability and environmental persistence, subjecting fragments to abiotic weathering prior to bacterial colonization. Marine isolates identified as Pseudomonas sp. and Lysinibacillus sp. exhibited decreasing biofilm formation on weathered HDPE, especially over the first 24 h of incubation. This effect was countered by increased extracellular matrix production, likely improving cell adhesion to surfaces roughened by abiotic degradation. These adhesion strategies were contrasted with a reference Pseudomonas aeruginosa strain, which displayed high levels of biofilm formation on non-weathered HDPE and lower extracellular matrix production over the first 24 h of incubation. Furthermore, our results suggest that an increase in biofilm biomass correlated with changes to HDPE structure, indicating that these strains have a potential for biodegradation of plastic fragments. Therefore, this work provides a detailed account of biofilm formation strategies and bacteria-plastic interactions that represent crucial steps in the biodegradation of plastic fragments in marine environments.

Asunto(s)

RESUMEN

The Mearim River Watershed has multiple uses e.g. leisure, navigation, fishing and subsistence agriculture and constitutes the main source of supply for the populations of municipalities situated along its course. In addition to being a water supply source, the existence of the 'pororoca' (tidal bore) effect in a stretch of the lower course of the Mearim River attracts people from several Brazilian states and different countries, as it offers excellent conditions for surfing in fresh water. In this respect, given the importance of the watershed, this study was developed to report the detection of diarrheagenic Escherichia coli pathotypes in a stretch of the lower course of the Mearim River, located in the state of Maranhão, Brazil. Thirty water samples were collected from 10 sampling points. To quantify E. coli, the chromogenic enzymatic system was used and positive samples were isolated and biochemically identified. Pure cultures underwent DNA extraction by heating followed by polymerase chain reaction (PCR) characterization. At the time of the collections, an observation schedule was used to record information on the existence of rearing of livestock and domestic animals; businesses; residences; and fruit and vegetable farming on the riverbanks. The samples were analyzed for the mean populations of E. coli, which ranged from 444 to 2,585 MPN mL-1. Twenty bacterial isolates were identified and the diarrheal pathotypes ETEC, typical EPEC and atypical EPEC were detected. The detection of these pathotypes can represent an epidemiological risk and compromise several uses of this water resource, such as irrigation of fruits and vegetables consumed raw, fishing, animal watering and recreation. Structural investments in basic sanitation are essential to minimize environmental degradation resulting from anthropic activities and to act preventively in public health. In addition, the recovery of riparian forests along the watershed and the maintenance of vegetation in these areas are measures to reduce the transport of particles from the soil to the watercourses, improving the qualitative and quantitative characteristics of this water resource.(AU)

A Bacia Hidrográfica do Rio Mearim apresenta múltiplos usos - lazer, navegação, pesca e agricultura de subsistência - e constitui a principal fonte de abastecimento para as populações dos municípios inseridos em seu curso. Além de fonte hídrica de abastecimento, a existência do efeito pororoca em um trecho do baixo curso do Rio Mearim atrai pessoas de vários estados brasileiros e diferentes países, pois apresenta excelentes condições para a prática de surfe em água doce. Nesse sentido, considerando a importância da Bacia Hidrográfica, objetivou-se relatar a detecção de patótipos diarreiogênicos de Escherichia coli em um trecho do baixo curso do rio Mearim, localizado no estado do Maranhão. Para isso, foram realizadas coletas de 30 amostras de água em 10 pontos amostrais. Para a quantificação de E. coli utilizou-se o sistema cromogênico enzimático e das amostras positivas procedeu-se ao isolamento e identificação bioquímica dos isolados. A extração do DNA das culturas puras foi realizada por aquecimento seguido da caracterização por reação em cadeia da polimerase (PCR). No momento das coletas utilizou-se uma pauta de observação para anotação de informações sobre a existência de criação de animais de interesse pecuário e doméstico, empreendimentos comerciais, residências e cultivo de frutas e hortaliças nas margens do rio. Nas amostras analisadas, foram quantificadas populações médias de E. coli que variaram de 444 a 2.585 NMP.mL-1, identificados 20 isolados bacterianos e detectados os patótipos diarreiogênicos ETEC, EPEC-típica e EPEC-atípica. A detecção destes patótipos pode representar risco epidemiológico e compromete diversos usos desse recurso hídrico, como a irrigação de frutas e hortaliças ingeridas cruas, pesca, dessedentação animal e recreação. Investimentos estruturais em saneamento básico são fundamentais para minimizar a degradação ambiental resultante das atividades antrópicas e para atuar preventivamente na saúde pública. Adicionalmente, a recuperação das matas ciliares ao longo da Bacia Hidrográfica e manutenção da vegetação nestas áreas são medidas para a redução do transporte de partículas do solo para os cursos d'água, e em consequência, acarretará na melhoria das características quali-quantitativas desse recurso hídrico.(AU)

Asunto(s)

RESUMEN

Eusocial animals, such as the termites, often build a nest-like structure called a mound that provides shelter with stable internal conditions and protection against predators. Termites are important components of the Brazilian Cerrado biota. This study aimed to investigate the bacterial community composition and diversity of the Syntermes wheeleri termite-mound soil using culture-independent approaches. We considered the vertical profile by comparing two different mound depths (mound surface and 60 cm) and seasonality with samplings during the rainy and dry seasons. We compared the mound soil microbiota to the adjacent soil without the influence of the mound to test the hypothesis that the Cerrado soil bacterial community was more diverse and more susceptible to seasonality than the mound soil microbiota. The results support the hypothesis that the Cerrado soil bacterial community is more diverse than the mound soil and also has a higher variability among seasons. The number of observed OTUs (Operational Taxonomic Units) was used to express bacterial richness, and it indicates that soil moisture has an effect on the community distribution and richness of the Cerrado samples in comparison to mound samples, which remain stable across seasons. This could be a consequence of the protective role of the mound for the termite colony. The overall community taxonomic profile was similar between soil samples, especially when compared to the taxonomic composition of the Syntermes wheeleri termite's gut, which might be explained by the different characteristics and functionality between the soil and the gut microbial community.

RESUMEN

Hand hygiene interventions are critical for reducing farmworker hand contamination and preventing the spread of produce-associated illness. Hand hygiene effectiveness may be produce-commodity specific, which could influence implementation strategies. This study's goal was to determine if produce commodity influences the ability of handwashing with soap and water or two-step alcohol-based hand sanitizer (ABHS) interventions to reduce soil and bacteria on farmworker hands. Farmworkers (n = 326) harvested produce (cantaloupe, jalapeño, and tomato) for 30 to 90 minutes before engaging in handwashing, two-step ABHS (jalapeño and cantaloupe), or no hand hygiene. Hands were rinsed to measure amounts of soil (absorbance at 600 nm) and indicator bacteria (coliforms, Enterococcus sp., generic Escherichia coli, and Bacteroidales universal [AllBac] and human-specific [BFD] 16S rRNA gene markers). Without hand hygiene, bacterial concentrations (0.88 to 5.1 log10 CFU/hand) on hands significantly differed by the produce commodity harvested. Moderate significant correlations (ρ = -0.41 to 0.56) between soil load and bacterial concentrations were observed. There were significant produce-commodity-specific differences in the ability of handwashing and two-step ABHS interventions to reduce soil (P < 0.0001), coliforms (P = 0.002), and Enterococcus sp. (P = 0.003), but not the Bacteroidales markers AllBac (P = 0.4) or BFD (P = 0.3). Contamination on hands of farmworkers who harvested cantaloupe was more difficult to remove. Overall, we found that a two-step ABHS intervention was similar to handwashing with soap and water at reducing bacteria on farmworker hands. In summary, produce commodity type should be considered when developing hand hygiene interventions on farms.IMPORTANCE This study demonstrated that the type of produce commodity handled influences the ability of handwashing with soap and water or a two-step alcohol-based hand sanitizer (ABHS) intervention to reduce soil and bacterial hand contamination. Handwashing with soap and water, as recommended by the FDA's Produce Safety Rule, when tested in three agricultural environments, does not always reduce bacterial loads. Consistent with past results, we found that the two-step ABHS method performed similarly to handwashing with soap and water but also does not always reduce bacterial loads in these contexts. Given the ease of use of the two-step ABHS method, which may increase compliance, the two-step ABHS method should be further evaluated and possibly considered for implementation in the agricultural environment. Taken together, these results provide important information on hand hygiene effectiveness in three agricultural contexts.

Asunto(s)

RESUMEN

The wide use of pesticides in agriculture expose microbiota to stressful conditions that require the development of survival strategies. The bacterial response to many pollutants has not been elucidated in detail, as well as the evolutionary processes that occur to build adapted communities. The purpose of this study was to evaluate the bacterial population structure and adaptation strategies in planktonic and biofilm communities in limited environments, as tanks containing water used for washing herbicide containers. This biodiversity, with high percentage of nonculturable microorganisms, was characterized based on habitat and abiotic parameters using molecular and bioinformatics tools. According to water and wastewater standards, the physicochemical conditions of the tank water were inadequate for survival of the identified bacteria, which had to develop survival strategies in this hostile environment. The biodiversity decreased in the transition from planktonic to biofilm samples, indicating a possible association between genetic drift and selection of individuals that survive under stressful conditions, such as heating in water and the presence of chlorine, fluorine and agrochemicals over a six-month period. The abundance of Enterobacter, Acinetobacter and Pseudomonas in biofilms from water tanks was linked to essential processes, deduced from the genes attributed to these taxonomic units, and related to biofilm formation, structure and membrane transport, quorum sensing and xenobiotic degradation. These characteristics were randomly combined and fixed in the biofilm community. Thus, communities of biofilm bacteria obtained under these environmental conditions serve as interesting models for studying herbicide biodegradation kinetics and the prospects of consortia suitable for use in bioremediation in reservoirs containing herbicide-contaminated wastewater, as biofilters containing biofilm communities capable of degrading herbicides.

RESUMEN

There is high demand for herbicides based on the necessity to increase crop production to satisfy world-wide demands. Nevertheless, there are negative impacts of herbicide use, manifesting as selection for resistant weeds, production of toxic metabolites from partial degradation of herbicides, changes in soil microbial communities and biogeochemical cycles, alterations in plant nutrition and soil fertility, and persistent environmental contamination. Some herbicides damage non-target microorganisms via directed interference with host metabolism and via oxidative stress mechanisms. For these reasons, it is necessary to identify sustainable, efficient methods to mitigate these environmental liabilities. Before the degradation process can be initiated by microbial enzymes and metabolic pathways, microorganisms need to tolerate the oxidative stresses caused by the herbicides themselves. This can be achieved via a complex system of enzymatic and non-enzymatic antioxidative stress systems. Many of these response systems are not herbicide specific, but rather triggered by a variety of substances. Collectively, these nonspecific response systems enhance the survival and fitness potential of microorganisms. Biodegradation studies and remediation approaches have relied on individually selected strains to effectively remediate herbicides in the environment. Nevertheless, it has been shown that microbial communication systems that modulate social relationships and metabolic pathways inside biofilm structures among microorganisms are complex; therefore, use of isolated strains for xenobiotic degradation needs to be enhanced using a community-based approach with biodegradation pathway integration. Bioremediation efforts can use omics-based technologies to gain a deeper understanding of the molecular complexes of bacterial communities to achieve to more efficient elimination of xenobiotics. With this knowledge, the possibility of altering microbial communities is increased to improve the potential for bioremediation without causing other environmental impacts not anticipated by simpler approaches. The understanding of microbial community dynamics in free-living microbiota and those present in complex communities and in biofilms is paramount to achieving these objectives. It is also essential that non-developed countries, which are major food producers and consumers of pesticides, have access to these techniques to achieve sustainable production, without causing impacts through unknown side effects.

RESUMEN

Abstract Objective: To evaluate the best strategy for pacifier disinfection methods. Material and Methods: The literature search was conducted on MEDLINE/PubMed, Scielo, Lilacs, Web of Science, and Scopus databases to find all relevant articles published over the past 20 years, based on PRISMA guidelines. Two reviewers extracted data independently by using a standardized form. The following factors were recorded: country of study, type of study, pacifier material, sample number, microorganisms analyzed, decontamination methods used, method accessibility and results found. Results: A total of 121 articles were obtained from all databases. The selected documents underwent a final screening, resulting in 8 articles. The method of disinfection analyzed by the literature were: 3.5% neutral detergent, apple cider vinegar 70% spray, boiling water during 15 minutes, sodium hypochlorite 2.5, hydrogen peroxide 70% spray, chlorhexidine 0.12%, Brushtox®, sterile water and microwave. Conclusion: Because of the broad methods for pacifier disinfection and different levels of accessibility to disinfectant agents, the pacifier consensus for decontamination remains unclear. Although the disinfection methods are diverse, the methods suggested to its disinfection were identified and described in this article.

Asunto(s)

RESUMEN

Resumen La biodiversidad de los microorganismos así como la naturaleza única y las capacidades biosintéticas en condiciones ambientales específicas hacen que los microorganismos sean los probables candidatos para resolver problemas de escases de alimentos, contro de plagas, biodegradación de los xenobióticos, descomposición de la basura, las pilas de desechos producidas, entre otros. Los microorganismos ofrecen un gran potencial para la exploración de moléculas y procesos, y el conocimiento de las especies no convencionales, especialmente dentro del grupo Archaea, ha estimulado la investigación molecular de genes de interés. Estos nuevos genes pueden incorporarse mediante tecnología recombinante en especies biológicamente conocidas, como E. coli y S. cerevisiae, para la síntesis a gran escala de productos. La microbiología tecnológica tiene grandes potenciales para explorar y obstáculos por superar. Por lo tanto, solo la investigación en esta área resulta prometedora para científicos en todo el mundo. En la presente revisión se presentan las aplicaciones más significativas de los microorganismos en la industria de alimentos, la agricultura, compuestos químicos, combustibles, farmacología y materiales.

Abstract The biodiversity of microorganisms as well as the unique nature and biosynthetic capabilities in specific environmental conditions make microorganisms the likely candidates to solve problems of food shortages, pest control, biodegradation of xenobiotics, decomposition of garbage, batteries of produced waste, among others. Microorganisms offer great potential for the exploration of molecules and processes, and knowledge of non-conventional species, especially within the Archaea group, has stimulated the molecular investigation of genes of interest. These new genes can be incorporated by recombinant technology into biologically known species, such as E. coli and S. cerevisiae, for the large-scale synthesis of products. Technological microbiology has great potentials to explore and obstacles to overcome. Therefore, only research in this area is promising for scientists around the world. In this review we present the most significant applications of microorganisms in the food industry, agriculture, chemical compounds, fuels, pharmacology and materials.

Asunto(s)

RESUMEN

Mangrove forests are highly productive yet vulnerable ecosystems that act as important carbon sinks ("blue carbon"). The objective of this work was to analyze the impact of anthropogenic activities on microbiome structure and functioning. The metagenomic analysis revealed that the taxonomic compositions were grossly similar across all mangrove microbiomes. Remarkably, these microbiomes, along the gradient of anthropogenic impact, showed fluctuations in the relative abundances of bacterial taxa predicted to be involved in sulfur cycling processes. Functions involved in sulfur metabolism, such as APS pathways (associated with sulfate reduction and sulfur oxidation processes) were prevalent across the microbiomes, being sox and dsrAB genes highly expressed on anthropogenically-impacted areas. Apparently, the oil-impacted microbiomes were more affected in taxonomic than in functional terms, as high functional redundancies were noted across them. The microbial gene diversity found was typical for a functional system, even following the previous disturbance.

Asunto(s)