Occurrence of pathogenic microorganisms in small drinking-water systems in Costa Rica.

This study describes the quality of drinking water sampled over 2 years (2018 and 2019) from 20 ASADAS (Spanish acronym for Administrative Associations for Water and Sewer Systems) in Costa Rica. The analysis included Rotavirus (RV), somatic coliphages, fecal coliforms, and Escherichia coli. The ASADAS were categorized into three regions as temperate rainy (region 1), tropical rainy (region 2), and tropical rainy and dry (region 3) according to biogeographic classification. The concentrations of fecal coliforms and E. coli were higher in samples from surface water sources from the ASADAS in region 3 compared to regions 1 and 2. RV-positive samples (24/296) were detected in drinking-water samples from regions 2 and 3 during dry and transition seasons, with higher concentrations more frequently in the dry season. In addition, somatic coliphages were detected in samples from the three regions, with higher concentrations in region 2. Furthermore, a statistically significant relationship was found between somatic coliphages and diarrheal cases, classified as outbreaks or alerts in the region. Thus, the results confirmed that somatic coliphages are a good indicator of the presence of diarrhea cases in a specific region.

Short-term exposure to benzalkonium chloride in bacteria from activated sludge alters the community diversity and the antibiotic resistance profile.

The continuous introduction of cleaning products containing benzalkonium chloride (BAC) from household discharges can mold the microbial communities in wastewater treatment plants (WWTPs) in a way still poorly understood. In this study, we performed an in vitro exposure of activated sludge from a WWTP in Costa Rica to BAC, quantified the changes in intI1, sul2, and qacE/qacEΔ1 gene profiles, and determined alterations in the bacterial community composition. The analysis of the qPCR data revealed elevated charges of antibiotic resistance genes in the microbial community; after BAC's exposure, a significant increase in the qacE/qacEΔ1 gene, which is related to ammonium quaternary resistance, was observed. The 16S rRNA gene sequences' analysis showed pronounced variations in the structure of the bacterial communities, including reduction of the alpha diversity values and an increase of the relative abundance of Alphaproteobacteria, particularly of Rhodospseudomonas and Rhodobacter. We confirmed that the microbial communities presented high resilience to BAC at the mg/mL concentration, probably due to constant exposure to this pollutant. They also presented antibiotic resistance-related genes with similar mechanisms to tolerate this substance. These mechanisms should be explored more thoroughly, especially in the context of high use of disinfectant.

A Somatic Coliphage Threshold Approach To Improve the Management of Activated Sludge Wastewater Treatment Plant Effluents in Resource-Limited Regions.

Effective wastewater management is crucial to ensure the safety of water reuse projects and effluent discharge into surface waters. Multiple studies have demonstrated that municipal wastewater treatment with conventional activated sludge processes is inefficient for the removal of a wide spectrum of viruses in sewage. In this study, a well-accepted statistical approach was used to investigate the relationship between viral indicators and human enteric viruses during wastewater treatment in a resource-limited region. Influent and effluent samples from five urban wastewater treatment plants (WWTPs) in Costa Rica were analyzed for somatic coliphage and human enterovirus, hepatitis A virus, norovirus genotypes I and II, and rotavirus. All WWTPs provide primary treatment followed by conventional activated sludge treatment prior to discharge into surface waters that are indirectly used for agricultural irrigation. The results revealed a statistically significant relationship between the detection of at least one of the five human enteric viruses and somatic coliphage. Multiple logistic regression and receiver operating characteristic curve analysis identified a threshold of 3.0 × 103 (3.5 log10) somatic coliphage PFU per 100 ml, which corresponded to an increased likelihood of encountering enteric viruses above the limit of detection (>1.83 × 102 virus targets/100 ml). Additionally, quantitative microbial risk assessment was executed for farmers indirectly reusing WWTP effluent that met the proposed threshold. The resulting estimated median cumulative annual disease burden complied with World Health Organization recommendations. Future studies are needed to validate the proposed threshold for use in Costa Rica and other regions.IMPORTANCE Effective wastewater management is crucial to ensure safe direct and indirect water reuse; nevertheless, few countries have adopted the virus log reduction value management approach established by the World Health Organization. In this study, we investigated an alternative and/or complementary approach to the virus log reduction value framework for the indirect reuse of activated sludge-treated wastewater effluent. Specifically, we employed a well-accepted statistical approach to identify a statistically sound somatic coliphage threshold value which corresponded to an increased likelihood of human enteric virus detection. This study demonstrates an alternative approach to the virus log reduction value framework which can be applied to improve wastewater reuse practices and effluent management.

Enterococci as a key parameter for water quality index: Purires River, Costa Rica.

This study used the Canadian Water Quality Index (CWI) to characterize water sampled at three points within the Purires River micro basin, Costa Rica. The first sampling point is located in a high zone with domestic agricultural activities, the second point around the mid-point of the flow of the river, and the third point at the lowest zone with extensive agricultural activities mainly centered on the production of fresh vegetables. Eleven physicochemical parameters (As, Cd, Cr, biochemical oxygen demand (BOD), chemical oxygen demand (COD), NH4 +, NO3 -, Pb, pH, percent saturation of dissolved oxygen (PSO), and total suspended solids (TSS)) and two microbiological parameters (fecal coliforms and enterococci) were evaluated. We evaluated three different Canadian Water Quality Indexes (CWIs): CWI-1 included only physicochemical parameters, CWI-2 included CWI-1 parameters plus fecal coliforms, and CWI-3 included CWI-2 in addition to enterococci. Statistical analysis of individual parameters showed significant differences between sampling sites. CWI-1 was unable to discriminate between the three sampling points, and characterized the water quality as 'fair'. CWI-2 was only able to discriminate when the water contained high levels of chemical and microbiological contaminants, while CWI-3 adequately discriminated water quality at each of the sampling points. The evaluation of enterococci together with more traditional water quality parameters enabled better categorization of surface water quality.

Mechanisms of low susceptibility to the disinfectant benzalkonium chloride in a multidrug-resistant environmental isolate of Aeromonas hydrophila.

Excessive discharge of quaternary ammonium disinfectants such as benzalkonium chloride (BAC) into aquatic systems can trigger several physiological responses in environmental microorganisms. In this study, we isolated a less-susceptible strain of Aeromonas hydrophila to BAC, designated as INISA09, from a wastewater treatment plant in Costa Rica. We characterized its phenotypic response upon exposure to three different concentrations of BAC and characterized mechanisms related to its resistance using genomic and proteomic approaches. The genome of the strain, mapped against 52 different sequenced A. hydrophila strains, consists of approximately 4.6 Mb with 4,273 genes. We found a massive genome rearrangement and thousands of missense mutations compared to the reference strain A. hydrophila ATCC 7966. We identified 15,762 missense mutations mainly associated with transport, antimicrobial resistance, and outer membrane proteins. In addition, a quantitative proteomic analysis revealed a significant upregulation of several efflux pumps and the downregulation of porins when the strain was exposed to three BAC concentrations. Other genes related to membrane fatty acid metabolism and redox metabolic reactions also showed an altered expression. Our findings indicate that the response of A. hydrophila INISA09 to BAC primarily occurs at the envelop level, which is the primary target of BAC. Our study elucidates the mechanisms of antimicrobial susceptibility in aquatic environments against a widely used disinfectant and will help better understand how bacteria can adapt to biocide pollution. To our knowledge, this is the first study addressing the resistance to BAC in an environmental A. hydrophila isolate. We propose that this bacterial species could also serve as a new model to study antimicrobial pollution in aquatic environments.

Cocoa Polyphenol Extract Inhibits Cellular Senescence via Modulation of SIRT1 and SIRT3 in Auditory Cells.

Cocoa, rich in polyphenols, has been reported to provide many health benefits due to its antioxidant properties. In this study, we investigated the effect of Cocoa polyphenols extract (CPE) against oxidative stress-induced cellular senescence using a hydrogen peroxide (H2O2)-induced cellular senescence model in three auditory cells lines derived from the auditory organ of a transgenic mouse: House Ear Institute-Organ of Corti 1 (HEI-OC1), Organ of Corti-3 (OC-k3), and Stria Vascularis (SV-k1) cells. Our results showed that CPE attenuated senescent phenotypes, including senescence-associated ß-galactosidase expression, cell proliferation, alterations of morphology, oxidative DNA damage, mitochondrial dysfunction by inhibiting mitochondrial reactive oxygen species (mtROS) generation, and related molecules expressions such as forkhead box O3 (FOXO3) and p53. In addition, we determined that CPE induces expression of sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3), and it has a protective role against cellular senescence by upregulation of SIRT1 and SIRT3. These data indicate that CPE protects against senescence through SIRT1, SIRT3, FOXO3, and p53 in auditory cells. In conclusion, these results suggest that Cocoa has therapeutic potential against age-related hearing loss (ARHL).

Preventive Effect of Cocoa Flavonoids via Suppression of Oxidative Stress-Induced Apoptosis in Auditory Senescent Cells.

Presbycusis or Age-related hearing loss (ARHL) is a sensorineural hearing loss that affects communication, leading to depression and social isolation. Currently, there are no effective treatments against ARHL. It is known that cocoa products have high levels of polyphenol content (mainly flavonoids), that are potent anti-inflammatory and antioxidant agents with proven benefits for health. The objective is to determine the protective effect of cocoa at the cellular and molecular levels in Presbycusis. For in vitro study, we used House Ear Institute-Organ of Corti 1 (HEI-OC1), stria vascularis (SV-k1), and organ of Corti (OC-k3) cells (derived from the auditory organ of a transgenic mouse). Each cell line was divided into a control group (CTR) and an H2O2 group (induction of senescence by an oxygen radical). Additionally, every group of every cell line was treated with the cocoa polyphenolic extract (CPE), measuring different markers of apoptosis, viability, the activity of antioxidant enzymes, and oxidative/nitrosative stress. The data show an increase of reactive oxidative and nitrogen species (ROS and RNS, respectively) in senescent cells compared to control ones. CPE treatment effectively reduced these high levels and correlated with a significant reduction in apoptosis cells by inhibiting the mitochondrial-apoptotic pathway. Furthermore, in senescence cells, the activity of antioxidant enzymes (Superoxide dismutase, SOD; Catalase, CAT; and Glutathione peroxidase, GPx) was recovered after CPE treatment. Administration of CPE also decreased oxidative DNA damage in the auditory senescent cells. In conclusion, CPE inhibits the activation of senescence-related apoptotic signaling by decreasing oxidative stress in auditory senescent cells.

Wastewater-Based Epidemiology of Enteric Viruses and Surveillance of Acute Gastrointestinal Illness Outbreaks in a Resource-Limited Region.

Acute gastrointestinal illness (AGI) continues to be an important cause of morbidity and mortality among all ages. This study applied the principles of wastewater-based epidemiology for the preventive identification of potential outbreaks of acute viral gastroenteritis and hepatitis A by analyzing the presence of human enteric viruses in influents of small municipal wastewater treatment plants (WWTPs) handling domestic sewage, together with public health reports of acute diarrheal and hepatitis A disease in Costa Rica during 2013. Raw wastewater samples were collected during four seasonal periods with different rainfall levels. The presence of five human enteric viruses (rotavirus A, norovirus GI, norovirus GII, enterovirus, and hepatitis A virus) was studied by endpoint and real-time polymerase chain reaction in influents of five WWTPs. Cases of AGI were analyzed using historical public health reports of endemic levels and quartile ranges for each administrative and territorial area where the WWTPs are located and for its surrounding counties. A tendency for a higher rate of positive viral tests was present 1 week before an increase of AGI cases. Epidemiological weeks categorized as Outbreak (above the 75th percentile) and Success (below the 25th percentile) showed statistically significant differences in terms of positive viral test rates (Wilcoxon test, P = 0.05). Virological monitoring of wastewater in small WWTPs is an appropriate model for epidemiological surveillance of diarrheal and hepatitis A diseases in low- and middle-resource countries.

Role of Oxidative Stress in the Senescence Pattern of Auditory Cells in Age-Related Hearing Loss.

Age-related hearing loss (ARHL) is an increasing and gradual sensorineural hearing dysfunction. Oxidative stress is an essential factor in developing ARHL; additionally, premature senescence of auditory cells induced by oxidative stress can produce hearing loss. Hydrogen peroxide (H2O2) represents a method commonly used to generate cellular senescence in vitro. The objective of the present paper is to study H2O2-induced senescence patterns in three auditory cell lines (House Ear Institute-Organ of Corti 1, HEI-OC1; organ of Corti, OC-k3, and stria vascularis, SV-k1 cells) to elucidate the intrinsic mechanisms responsible for ARHL. The auditory cells were exposed to H2O2 at different concentrations and times. The results obtained show different responses of the hearing cells concerning cell growth, ß-galactosidase activity, morphological changes, mitochondrial activation, levels of oxidative stress, and other markers of cell damage (Forkhead box O3a, FoxO3a, and 8-oxoguanine, 8-oxoG). Comparison between the responses of these auditory cells to H2O2 is a helpful method to evaluate the molecular mechanisms responsible for these auditory cells' senescence. Furthermore, this in vitro model could help develop anti-senescent therapeutic strategies for the treatment of AHRL.

Draft Genome Sequence of an Escherichia coli Strain Harboring bla CTX-M-115, bla CMY-2, Aminoglycoside, Tetracycline, and Sulfonamide Resistance Genes, Isolated from a Costa Rican Wastewater Treatment Plant.

We report the draft genome sequence of the multidrug-resistant Escherichia coli strain PTA A1517-5, isolated from a wastewater treatment plant in Costa Rica. The genome consists of 4,927,375 bp with a GC content of 50.57% and a total of 4,853 genes. This strain harbors bla CTX-M-115, bla CMY-2, aminoglycoside, tetracycline, and sulfonamide resistance genes.

Evaluación de la influencia de la estacionalidad climática en calidad del agua de consumo humano en un sistema de abastecimiento en San José, Costa Rica, periodo 2017-2018 / Evaluation of climatic seasonal influence on the quality of water for human consumption in a San José (Costa Rica) supply system, 2017-2018

Resumen Objetivo: Analizar el estado y la influencia de la variabilidad climática en la calidad del agua de un sistema de abastecimiento para consumo humano en San José, Costa Rica, captado en cuatro microcuencas del cantón Vásquez de Coronado, en el periodo 2017-2018, para brindar recomendaciones al operador y promover la protección de la población abastecida Métodos: Estudio descriptivo de los parámetros de calidad básicos de agua para consumo humano (Escherichia coli, coliformes fecales, turbidez, conductividad, pH, color, temperatura y cloro residual). Los análisis se realizaron siguiendo el Standard Methods for the Examination of Water and Wastewater. Se delimitaron las zonas de captación utilizando sistemas de información geográfica. Se utilizó estadística descriptiva e inferencial para describir la calidad del agua y su variabilidad espacial y estacional. Resultados: La concentración de coliformes fecales en el agua superficial fue > 103 NMP/100 mL y la turbidez >5 UTN en el 76% de las muestras. En la red de distribución se encontraron concentraciones de cloro residual y turbidez (>5 UTN) por encima de los límites recomendados para agua de consumo humano. Se encontró diferencias significativas en todos los parámetros básicos de calidad de agua entre las distintas zonas de captación (p<0,05 en todos los casos), así como entre épocas climáticas por zona de captación. Conclusión: Estos resultados indican que se está utilizando agua de calidad inadecuada para uso y consumo humano, por lo cual se recomienda un monitoreo intensivo y sectorizado de las fuentes para localizar puntos de contaminación.

Abstract Objective: Analyze the water quality and the influence of the climatic variability in supply system for the human consume in San José, Costa Rica, in four catchment areas in Vasquez of Coronado in the period 2017-2018 to give recommendations to the operator and promote the protection of the supplied population. Methods: Descriptive study of the basic parameters of the drinking water (Escherichia coli, fecal coliforms, turbidity, conductivity, pH, color, temperature, and residual chlorine). The analyses were done following Standard Methods for the examination of Water and Wastewater. The catchment areas were delimited using geographic information systems (GIS). Descriptive and inferential statistic was used to describe the water quality, spatial and seasonal variability. Results: The concentration of fecal coliforms in the catchment areas was >10 3 NMP/100 mL and the turbidity >5 UTN in 76% of the samples. In the distribution system were found concentrations of the residual chlorine and turbidity (>5 UTN) above according to recommended limits for drinking water in the country. The results showed significant differences in all of the basic parameters of the water quality between catchment areas (p<0, 05 in all cases) and between climatic periods for catchment areas. Conclusion: These results indicate that water of inadequate quality is being used for human use and consumption, for which reason intensive and sectorized source monitoring is recommended to locate contamination points.

Contaminación fecal del agua superficial de la microcuenca del río Purires, Costa Rica, 2010-2011 / Fecal contamination of the superficial water of the microbasin of Rio Purires, Costa Rica, 2010-2011

La contaminación fecal de las aguas superficiales es un problema importante para la salud pública, dada la transmisión de microorganismos patógenos. Se estima que las poblaciones ubicadas cerca de costas, ríos o lagos con elevada contaminación fecal, tienen mayor riesgo de desarrollar enfermedades infecciosas gastrointestinales. En esta investigación se analizó durante un año, la contaminación fecal en las aguas superficiales de la microcuenca del río Purires, ubicada en una zona de alta densidad poblacional en Costa Rica. En el 100% de las muestras se detectó contaminación fecal, siendo el punto de muestreo 3 el que mostró los niveles más altos, en promedio 2,2 x 10(4) Número Más Probable(NMP)/100()mL. Aunque los puntos 1 y 2 presentaron menor contaminación fecal, en promedio 6,4 x 10² NMP/100 mL y 6,3 x 10³ NMP/100 mL respectivamente, estos valores indican también mala calidad de las aguas. Con estos resultados se pretende llamar la atención sobre la problemática ambiental de alta contaminación fecal en las aguas superficiales de esta microcuenca. Esta información es un insumo para desarrollar acciones de control sobre las fuentes de contaminación que afectan la calidad de las aguas y por ende, la salud de las poblaciones ubicadas en su cercanía.

Fecal contamination of the superficial waters is an important public health problem due to the presence of pathogenic microorganisms- It has been estimated that populations located close to coasts, rivers of lakes with an elevated fecal contamination have a higher risk of developing communicable gastrointestinal diseases. This investigation analyzed the fecal contamination of the superficial waters of the microbasin of the Rio Purires, located in a highly populated area of Costa Rica. Fecal contamination was detected in 100% of the samples, and sample point 3 was the one that showed the highest levels, with an average of 2.2 x 10(4) Most Probable Number (MPN)/100mL. Even thought points 1 and 2 presented a lower fecal contamination, an average of 6.4 x 10² MPN/100mL and 6.3 x 10³ MPN/100mL, respectively, these values also indicate low quality water. With these results we intend to alert regarding the problem of a high fecal contamination of superficial waters of this microbasin. This information is an input for developing control actions over the contamination sources which compromise the quality of water and, therefore, the health of the populations located in its vicinity.

Estandarización de una PCR para la detección del gen invA de Salmonella spp. en lechuga / Standardization of a PRC method for the detection of the Salmonella spp. invA gene in lettuce

Salmonella spp. es un patógeno bacteriano muy importante causante de diarreas, que es transmitido tanto por la vía fecal-oral, como por alimentos y agua contaminados. En este trabajo se estandarizó una técnica de PCR en lechuga para la detección del gen invA de Salmonella spp.; dicho gen se relaciona con el proceso de invasión al epitelio intestinal. Con la PCR desarrollada en este trabajo se logró estandarizar un método que permite la amplificación del gen invA con una detección de 10² UFC/25 g. Este método acorta los tiempos de respuesta de los resultados presuntivos y brinda información complementaria al cultivo tradicional del patógeno. El estudio del gen invA establece el potencial patógeno del microorganismo presente en la muestra, lo que puede ser de utilidad para la salud pública.

Salmonella spp. is a very important bacterial pathogen that causes diarrhea and which is transmitted both through the fecal-oral pathway, as by contaminated food and water. In this study we standardized a PCR method in lettuce for the detection of the Salmonella spp. invA gene. This gene is related to the invasion of the intestinal epithelium process. With the PCR method developed in this study we were able to standardize a method which permits the amplification of the invA gene with a 10² CFU/25 g detection. This method shortens the response times of the presumptive results and gives complementary information to the traditional culture of the pathogen. The study of the invA gene establishes the pathogenic potential of the microorganism present in the sample, which can be useful for public health purposes.

Factores socioculturales que influen en la solicitud oportuna de servicios de salud oral en la Unidad de Odontologia del Hospital Local San Jose de Guaduas / Sociocultural factors that influence timely solicitute of oral health services in the dentistry unit from the local Hosipital San Jose de Guaduas

Este estudio identifica los factores socioculturales relacionados con la prevencion de caries dental en ninos de 7-14 anos que determinan la solicitud oportuna de los servicios odontologicos del hospital. Para ello se entrevistaron 106 ninos con base en un cuestionario previamente elaborado durante el perido comprendido entre el 1 de septiembre y el 30 de octubre de 1982, que acudieron a la unidad odontologica del Hospital San Jose de Guaduas encontrandose que el nivel eoconomico de la familia no influye en la oprtunidad de la solicitud mientras que si lo hacen las actividades negativas de la familia que los lleva a recurrir a practicas empriricas para aliviar los sintomas antes de solicitar el servicio odontologico. Se sugiere establecer programas educativos integrales de salud oral mejorando el personal, la dotacion y el mantenimiento de la unidad odontologica del Hosptial e integrar el componente de salud oral a los programas de salud infantil..