Hyperthermophile diversity microbes in the Calientes geothermal field, Tacna, Peru.

Hyperthermophile microorganisms have been discovered worldwide, and several studies regarding biodiversity and the potential biotechnological applications have been reported. In this work, we describe for the first time the diversity of hyperthermophile communities in the Calientes Geothermal Field (CGF) located 4400 m above sea level in Tacna Region, Perú. Three hot springs were monitored and showed a temperature around 84 to 88 °C, for the microbiome analyzed was taken by sampling of sediment and water (pH 7.3-7.6). The hyperthermophile diversity was determined by PCR, DGGE, and DNA sequencing. The sediments analyzed showed a greater diversity than water samples. Sediments showed a more abundant population of bacteria than archaea, with the presence of at least 9 and 5 phylotypes, respectively. Most interestingly, in some taxa of bacteria (Bacillus) and archaea (Haloarcula and Halalkalicoccus), any of operational taxonomic units (OTUs) have not been observed before in hyperthermophile environments. Our results provide insight in the hyperthermophile diversity and reveal the possibility to develop new biotechnological applications based on the kind of environments.

Use of Onion Waste as Fuel for the Generation of Bioelectricity.

The enormous environmental problems that arise from organic waste have increased due to the significant population increase worldwide. Microbial fuel cells provide a novel solution for the use of waste as fuel for electricity generation. In this investigation, onion waste was used, and managed to generate maximum peaks of 4.459 ± 0.0608 mA and 0.991 ± 0.02 V of current and voltage, respectively. The conductivity values increased rapidly to 179,987 ± 2859 mS/cm, while the optimal pH in which the most significant current was generated was 6968 ± 0.286, and the ° Brix values decreased rapidly due to the degradation of organic matter. The microbial fuel cells showed a low internal resistance (154,389 ± 5228 Ω), with a power density of 595.69 ± 15.05 mW/cm2 at a current density of 6.02 A/cm2; these values are higher than those reported by other authors in the literature. The diffractogram spectra of the onion debris from FTIR show a decrease in the most intense peaks, compared to the initial ones with the final ones. It was possible to identify the species Pseudomona eruginosa, Acinetobacter bereziniae, Stenotrophomonas maltophilia, and Yarrowia lipolytica adhered to the anode electrode at the end of the monitoring using the molecular technique.

Effect of CO2 Concentration on Uptake and Assimilation of Inorganic Carbon in the Extreme Acidophile Acidithiobacillus ferrooxidans.

This study was motivated by surprising gaps in the current knowledge of microbial inorganic carbon (Ci) uptake and assimilation at acidic pH values (pH < 3). Particularly striking is the limited understanding of the differences between Ci uptake mechanisms in acidic versus circumneutral environments where the Ci predominantly occurs either as a dissolved gas (CO2) or as bicarbonate (HCO3 -), respectively. In order to gain initial traction on the problem, the relative abundance of transcripts encoding proteins involved in Ci uptake and assimilation was studied in the autotrophic, polyextreme acidophile Acidithiobacillus ferrooxidans whose optimum pH for growth is 2.5 using ferrous iron as an energy source, although they are able to grow at pH 5 when using sulfur as an energy source. The relative abundance of transcripts of five operons (cbb1-5) and one gene cluster (can-sulP) was monitored by RT-qPCR and, in selected cases, at the protein level by Western blotting, when cells were grown under different regimens of CO2 concentration in elemental sulfur. Of particular note was the absence of a classical bicarbonate uptake system in A. ferrooxidans. However, bioinformatic approaches predict that sulP, previously annotated as a sulfate transporter, is a novel type of bicarbonate transporter. A conceptual model of CO2 fixation was constructed from combined bioinformatic and experimental approaches that suggests strategies for providing ecological flexibility under changing concentrations of CO2 and provides a portal to elucidating Ci uptake and regulation in acidic conditions. The results could advance the understanding of industrial bioleaching processes to recover metals such as copper at acidic pH. In addition, they may also shed light on how chemolithoautotrophic acidophiles influence the nutrient and energy balance in naturally occurring low pH environments.

Bioelectrogenesis with microbial fuel cells (MFCs) using the microalga Chlorella vulgaris and bacterial communities

Background: Microbial Fuel Cell (MFC) technology is used in various applications such as wastewater treatment with the production of electrical energy. The objective of this study was to estimate the biodepuration of oils and fats, the elimination of blue dye brl and bioelectro-characterization in MFCs with Chlorella vulgaris and bacterial community. Results: The operation of MFCs at 32 d showed an increase in bioelectrogenic activity (from 23.17 to 327.67 mW/m2 ) and in the potential (from 200 to 954 mV), with biodepuration of fats and oils (95%) in the microalgal cathode, and a removal of the chemical oxygen demand COD (anode, 71%, cathode, 78.6%) and the blue dye brl (73%) at the anode, here biofilms were formed by the bacterial community consisting of Actinobacteria and Deltaproteobacteria. Conclusions: These findings suggest that MFCs with C. vulgaris and bacterial community have a simultaneous efficiency in the production of bioelectricity and bioremediation processes, becoming an important source of bioenergy in the future.

MÉTODOS DE TIPIFICACIÓN Y EPIDEMIOLOGÍA MOLECULAR DE Staphylococcus aureus CON RESISTENCIA A LA METICILINA / TIPIFICATION METHODS AND MOLECULAR EPIDEMIOLOGY OF Staphylocuccus aureus WITH METHICILLIN RESISTANCE

El interés actual del estudio de Staphylococcus aureus deriva de su elevada frecuencia de cepas resistentes a los antibióticos que causa frecuentes brotes de infección, especialmente, el S. aureus con resistencia a meticilina (SARM). El objetivo de esta revisión fue estudiar la estructura genética poblacional y el origen de los aislamientos de SARM. La tipificación del cassette cromosómico mec estafilocócico es el método más importante para identificar y definir la naturaleza clonal del S. aureus con resistencia a meticilina. Los estudios de epidemiología molecular evidencian un patrón de diseminación de unas pocas cepas que son las responsables del importante problema mundial. Existe el predominio de clones pandémicos de SARM asociado a infecciones hospitalarias (SARM-AH), que ha han sido reemplazados en la actualidad por clones de origen comunitario (SARM-AC). En Colombia, predomina el clon pediátrico y el chileno entre los aislamientos hospitalarios. Sin embargo, en la actualidad una variante del clon comunitario USA300 prevalece en las infecciones adquiridas en la comunidad y en el hospital, desplazando los clones hospitalarios como ocurre en el resto de mundo. El entendimiento de la epidemiología y clonalidad de las infecciones por S. aureus tiene importantes implicaciones en el control de la emergencia de cepas con multirresistencia y el esparcimiento de clones resistentes y sensibles a meticilina.

Recent interest in the study of Staphylococcus aureus derives from the high frequency of antibiotic-resistant strains that cause frequent outbreaks of infection, especially Methicillin-resistant S. aureus (MRSA). The objective of this review was to study the population genetic structure and the origin of MRSA isolation. Classification of staphylococcal cassette chromosome mec (SCCmec) is the most important method to identify and define the S. aureus methicillin-resistant clonal nature. Molecular epidemiologic studies have demonstrated dissemination patterns of few strains which are responsible for the important worldwide problem. There is a predominance of pandemic clones of MRSA associated to hospital-acquired infections (HA-MRSA) which has been replaced today by community-acquired strains (CA-MRSA). In Colombia, the pediatric clone and the Chilean clone predominate between hospital isolations. However, currently, there is a variant community clone USA300 prevailing in infections acquired in the community and in the hospital, displacing HA-MRSA as it happens in the rest of world. Understanding the epidemiology and clonality of S. aureus infections has important implications for future efforts to control of the emergence of multidrug-resistant strains and the spread of clones resistant and sensible to methicillin.

Expression and activity of the Calvin-Benson-Bassham cycle transcriptional regulator CbbR from Acidithiobacillus ferrooxidans in Ralstonia eutropha.

Autotrophic fixation of carbon dioxide into cellular carbon occurs via several pathways but quantitatively, the Calvin-Benson-Bassham cycle is the most important. CbbR regulates the expression of the cbb genes involved in CO2 fixation via the Calvin-Benson-Bassham cycle in a number of autotrophic bacteria. A gene potentially encoding CbbR (cbbR(AF)) has been predicted in the genome of the chemolithoautotrophic, extreme acidophile Acidithiobacillus ferrooxidans. However, this microorganism is recalcitrant to genetic manipulation impeding the experimental validation of bioinformatic predictions. Two novel functional assays were devised to advance our understanding of cbbR(AF) function using the mutated facultative autotroph Ralstonia eutropha H14 ΔcbbR as a surrogate host to test gene function: (i) cbbR(AF) was expressed in R. eutropha and was able to complement ΔcbbR; and (ii) CbbR(AF) was able to regulate the in vivo activity of four A. ferrooxidans cbb operon promoters in R. eutropha. These results open up the use of R. eutropha as a surrogate host to explore cbbR(AF) activity.

Cobre antimicrobiano contra patógenos intrahospitalarios en Perú / Antimicrobial copper against nosocomial pathogens in Peru

Las infecciones intrahospitalarias (IIH) constituyen un problema de salud pública que generan grandes gastos por parte de los gobiernos, debido a que los patógenos causantes de IIH presentan resistencia a fármacos y generan una mayor permanencia de los pacientes, pues la infraestructura hospitalaria constituye un reservorio favorable para los patógenos. Las superficies de cobre surgen como opción sanitaria y efectiva para controlar el crecimiento y propagación de estos patógenos. Objetivos: Evaluar la actividad bactericida de las superficies de cobre contra los principales bacterias patógenas causantes de IIH (Escherichia coli, Pseudomonas aeruginosa y Staphylococcus aureus). Diseño: Estudio experimental con muestreo no probabilístico. Lugar: Hospital Regional Docente las Mercedes (HRDLM) y Hospital Provincial Docente Belén (HPDB), Lambayeque, Perú. Materiales: Nueve cepas bacterianas, 3 de E. coli, 3 de P. aeruginosa y 3 de S. aureus; superficies metálicas (1 cm2) de cobre y acero inoxidable (control). Intervenciones: Las 9 cepas bacterianas fueron proporcionadas por los hospitales HRDLM (4 cepas) y HPDB (5 cepas). Los análisis de ANOVA y de Tukey fueron aplicados para evaluar la actividad bactericida de las superficies de cobre y acero inoxidable contra las 9 cepas causantes de IIH, usando los programas estadísticos Minitab y Sigmaplot, respectivamente. Principales medidas de resultados: Diferencias en el crecimiento bacteriano sobre superficies de cobre o acero inoxidable, con respecto al tiempo de exposición. Resultados: Las 9 cepas -3 de P. aeruginosa, 3 de E. coli y 3 de S. aureus- expuestas a superficies de cobre fueron eliminadas en 10, 15 y 60 minutos, respectivamente. La carga bacteriana de las células expuestas en superficies de acero inoxidable permaneció constante y viable por periodos mayores a 60 minutos. Además, las superficies de cobre eliminaron más rápido a las bacterias Gram negativas (P. aeruginosa y E. coli) con respecto...

Nosocomial infections (NI) generate large expenditures by governments, as NI pathogens are resistant to drugs and increase hospital stay. Copper surfaces seem a promising alternative to control growth and spread of these pathogens. Objectives: To evaluate copper surfaces bactericidal activity against pathogenic bacteria causing NI (E. coli, P. aeruginosa and S. aureus). Design: Experimental study with non-probability sampling. Institutions: Hospital Regional Docente las Mercedes (HRDLM) and Hospital Provincial Docente Belen (HPDB), Lambayeque, Peru. Materials: Nine bacterial strains of E. coli, P. aeruginosa and S. aureus, metal surfaces (1 cm2) of copper and stainless steel (control). Interventions: Bacterial strains were provided by HRDLM (4 strains) and HPDB (5 strains). ANOVA and Tukey analysis were applied to evaluate copper and stainless steel surfacesÆ bactericidal activity to strains causing NI; Minitab statistical software and Sigmaplot were used. Main outcome measures: Differences in bacterial growth on metal surfaces (copper or stainless steel) with respect to exposure time. Results: The nine strains of P. aeruginosa (3), E. coli (3) and S. aureus (3) exposed to copper surfaces were inactivated after 10, 15, and 60 minutes respectively. The bacterial load of cells exposed to stainless steel surfaces remained constant and viable for periods longer than 60 minutes. Copper surfaces removed Gram-negative bacteria (E. coli and P. aeruginosa) faster than Gram-positive bacteria (S. aureus). Conclusions: Copper surfaces completely eliminated studied nosocomial bacteria. Thus they could replace steel as contact surfaces in Peruvian health facilities with high incidence of NI...

Patrones de resistencia a antibióticos de Acinetobacter baumannii en un hospital de Colombia / Patterns of Acinetobacter baumannii resistance to antibiotics in a Colombian hospital

Identificar patrones de resistencia en los aislamientos de A. baumannii obtenidos en una unidad de cuidados intensivos de Cali, Colombia. Diseño: Estudio descriptivo, prospectivo de corte transversal. Institución: Clínica Universitaria Rafael Uribe Uribe, Cali, Colombia. Materiales: Los aislamientos se obtuvieron de cultivos de muestras de sangre, heridas quirúrgicas, secreción nasal, orina, secreción uretral y puntas de catéter. Intervenciones: Se recolectaron 52 aislamientos durante los años 2009 y 2010. Mediante el análisis del antibiograma se identificaron patrones de resistencia (antibiotipos), se realizó antibiograma cuantitativo y se construyó un cladograma basado en el agrupamiento por el método de promedios aritméticos de grupos apareados no ponderados (conocido en inglés como UPGMA). Principales medidas de resultados: Medida de la concentración mínima inhibitoria (CMI) y el coeficiente de similitud generado por las distancias de los diámetros de los halos de inhibición entre dos aislamientos (antibiograma cuantitativo). Resultados: Se identificaron 5 antibiotipos; el 50 por ciento de los aislamientos se agruparon en el antibiotipo 1, con resistencia a todos los antibióticos y sensibilidad a tigeciclina y sulperazona; el antibiotipo 4 agrupó los aislamientos con resistencia a todos los antibióticos (19,3 por ciento). En el antibiograma cuantitativo se identificaron dos clados con 5 y 47 aislamientos, respectivamente. Conclusiones: Los aislamientos de Acinetobacter baumannii tuvieron pocas diferencias fenotípicas y es probable que presenten alguna de las ß-lactamasas tipo OXA...

To identify patterns of resistance in A. baumannii isolates obtained from an intensive care unit in Cali, Colombia. Design: Prospective cross-sectional descriptive study. Institution: Clínica Universitaria Rafael Uribe Uribe, Cali, Colombia. Materials: Isolates were obtained from cultures of blood, surgical wounds, nasal secretion, urine, urethral discharge and catheter tip samples. Interventions: Fifty-two isolates were collected between 2009 and 2010. Antibiogram analysis was done to identify resistance patterns (antibiotypes), a quantitative susceptibility testing was conducted, and a cladogram based on unweighted pair group method average (UPGMA) was constructed. Main outcome measures: Minimum inhibitory concentration (MIC) and similarity coefficient generated by diameters distances between two isolated inhibition zones (quantitative antibiogram). Results: Five antibiotypes were identified; 50 per cent of isolates were grouped in antibiotype 1, were resistant to all antibiotics, and susceptible to tigecycline and sulperazone; antibiotype 4 grouped isolates resistant to all antibiotics (19.3 per cent). In the quantitative antibiogram two clades with 5 and 47 isolates were identified respectively. Conclusions: Acinetobacter baumannii isolates showed few phenotypic differences and probably present some of ß-lactamases OXA type...

Anaerobic sulfur metabolism coupled to dissimilatory iron reduction in the extremophile Acidithiobacillus ferrooxidans.

Gene transcription (microarrays) and protein levels (proteomics) were compared in cultures of the acidophilic chemolithotroph Acidithiobacillus ferrooxidans grown on elemental sulfur as the electron donor under aerobic and anaerobic conditions, using either molecular oxygen or ferric iron as the electron acceptor, respectively. No evidence supporting the role of either tetrathionate hydrolase or arsenic reductase in mediating the transfer of electrons to ferric iron (as suggested by previous studies) was obtained. In addition, no novel ferric iron reductase was identified. However, data suggested that sulfur was disproportionated under anaerobic conditions, forming hydrogen sulfide via sulfur reductase and sulfate via heterodisulfide reductase and ATP sulfurylase. Supporting physiological evidence for H2S production came from the observation that soluble Cu(2+) included in anaerobically incubated cultures was precipitated (seemingly as CuS). Since H(2)S reduces ferric iron to ferrous in acidic medium, its production under anaerobic conditions indicates that anaerobic iron reduction is mediated, at least in part, by an indirect mechanism. Evidence was obtained for an alternative model implicating the transfer of electrons from S(0) to Fe(3+) via a respiratory chain that includes a bc(1) complex and a cytochrome c. Central carbon pathways were upregulated under aerobic conditions, correlating with higher growth rates, while many Calvin-Benson-Bassham cycle components were upregulated during anaerobic growth, probably as a result of more limited access to carbon dioxide. These results are important for understanding the role of A. ferrooxidans in environmental biogeochemical metal cycling and in industrial bioleaching operations.

Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, carbon fixation in A. ferrooxidans.

BACKGROUND: Acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2). Although a substantial amount of information is available regarding CO2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. RESULTS: Four gene clusters (termed cbb1-4) in the A. ferrooxidans genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB) cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39) and the CO2-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon cbb1 is divergently transcribed from a gene, cbbR, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma70-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N11-A/TNA-N7TNA) were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs) confirmed that purified CbbR is able to bind to the upstream regions of the cbb1, cbb2 and cbb3 operons, demonstrating that the predicted CbbR-binding sites are functional in vitro. However, CbbR failed to bind the upstream region of the cbb4 operon that contains cbbP, encoding phosphoribulokinase (EC 2.7.1.19). Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The cbb3 operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO2 fixation and tryptophan biosynthesis. The presence of a form II RubisCO could promote the ability of A. ferrooxidans to fix CO2 at different concentrations of CO2. CONCLUSIONS: A. ferrooxidans has features of cbb gene organization for CO2-assimilating functions that are characteristic of obligate chemolithoautotrophs and distinguish this group from facultative autotrophs. The most conspicuous difference is a separate operon for the cbbP gene. It is hypothesized that this organization may provide greater flexibility in the regulation of expression of genes involved in inorganic carbon assimilation.

Characterization of the most prevalent colonization factor antigens present in Chilean clinical enterotoxigenic Escherichia coli strains using a new multiplex polymerase chain reaction.

Current methods to detect the colonization factor antigens (CFAs) associated with enterotoxigenic Escherichia coli (ETEC) strains are cumbersome, with some methods requiring antibodies that are not readily available. To achieve a gene-based method, we designed 2 multiplex polymerase chain reaction reactions to detect genes encoding the most common ETEC fimbrial colonization factors, including CFA/I and coli surface (CS) antigens CS1, CS2, CS3, CS4, CS5, and CS6. Analysis of 183 clinical ETEC strains shows that the most prevalent colonization factors were CFA/I only, CS1 and CS3, CS2 and CS3, and CS6 only. Interestingly, we identified 3 clinical isolates expressing CS1 only without its regulator rns. The method described here proved to be rapid and robust and correlates well with phenotypic expression of the CFAs, becoming a novel molecular diagnostic and research tool for future epidemiologic studies.

HPLC-fluorescence detection and adsorption of bisphenol A, 17beta-estradiol, and 17alpha-ethynyl estradiol on powdered activated carbon.

The adsorption of three estrogenic compounds (bisphenol A (BPA), 17beta-estradiol (E2), and 17alpha-ethynyl estradiol (EE2)) on several powdered activated carbons (PAC) was investigated. Without preconcentration, method detection limits (MDL) using high-performance liquid chromatography (HPLC) with fluorescence detection at an excitation wavelength of 280 nm and an emission wavelength of 310 nm were 0.88, 1.15, and 0.96 nM for BPA, E2, and EE2, respectively. Compound recoveries were >90% in raw drinking water matrices. PAC screening studies (six PAC brands) indicated all three compounds were removed by PAC, but the percentage removal ranged from 31% to >99% based upon PAC type/dosage and presence/absence of natural organic matter. The order of removal (E2>EE2>BPA) corresponded with logK(ow) values for the compounds (3.1-4.0, 3.7-3.9, 3.3, respectively). Kinetic and PAC dose-response experiments were conducted with the two best performing PACs. Increasing contact time and PAC dose improved compound removal. Freundlich isotherm parameters were fit to the experimental data. This study confirms that PAC treatment is feasible for >99% removal of three estrogenic compounds from raw drinking waters that may be at risk for containing such compounds, at least at initial concentration of 500 ng/l and higher.