Browsing by Autor "Sanguino-Jorquera, Diego Gastón"

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Acanthamoeba and a bacterial endocytobiont isolated from recreational freshwaters.
(2022) Sanguino-Jorquera, Diego Gastón; Rajal, Verónica Beatriz; Juárez, María Mercedes; Poma, Hugo Ramiro; Irazusta, Verónica Patricia
The quality of many freshwater environments is impacted by human activities, so that many rivers may represent a vehicle for the transmission of health-related microorganisms. This work aimed to isolate and identify genetically free-living amoeba (FLA) of the genus Acanthamoeba from a recreational river in Salta, Argentina, and isolate, if possible, an endocytobiont. Sampling took place at four points (P1-P4) throughout the river in the winter and the summer seasons. Free-living amoebae and Acanthamoeba were recovered from 20-L water concentrated through an ultrafiltration system. Isolation was performed in agar plates, confirmation of Acanthamoeba genus by PCR, and fellow identification and classification based on their sequence analyses. High concentrations of indicator bacteria were found especially in P2, which is intensively used for recreation. Out of a total of 29 FLA isolations, 9 were identified as Acanthamoeba genotype T4 subtype A, the most frequent genotype found in nature and associated with causing human disease. From an axenic culture of Acanthamoeba spp. (KY751412), a bacterial endocytobiont was isolated, and identified as Stenotrophomonas maltophilia. The endocytobiont showed resistance and intermediate resistance to a wide range of widely used antibiotics. Results were in concordance with the cosmopolitan behavior of Acanthamoeba, and showed the importance of studying this group of amoebae and related microorganisms in recreational environments.
An integrative analysis of SARS-CoV 2 during the first and second waves of COVID-19 in Salta, Argentina.
(2024) Sanguino-Jorquera, Diego Gastón; Mainardi-Remis, Juan Martín; Maidana-Kulesza, María Noel; Cruz, Mercedes Cecilia; Poma, Hugo Ramiro; González, Mónica Aparicio; Irazusta, Verónica Patricia; Rajal, Verónica Beatriz
Wastewater surveillance has been extensively applied to provide information about SARS-CoV-2 circulation in the community. However, its applicability is limited in regions lacking adequate sewerage infrastructure, without wastewater treatment plants (WWTP) or with insufficient coverage. During the COVID-19 pandemic, from July 2020 to September 2021, comprehensive epidemiological data encompassing positive, recovered, and deceased cases were collected alongside precipitation records. Additionally, wastewater samples from 13 main sewersheds and river water from two points (up- and downstream the main WWTP), in the city of Salta, were gathered. A total of 452 water samples were analyzed for quantitative detection of SARS-CoV-2 using reverse transcription real-time PCR. Across the 62-week study period, two distinct waves of COVID-19 were identified. The dynamics of deceased cases showed peaks 10 and 28 days after the peaks of positive cases in the first and second waves, respectively. Downstream river water exhibited higher fecal contamination than the upstream samples, evincing the impact of the WWTP discharges. Viral concentration in river waters mirrored those from wastewater, reflecting the progression of cases. Despite the lower reported number of cases during the first wave in comparison to the second (5420 vs. 8516 cases at the respective peaks), higher viral concentrations were detected in water samples (1.97 × 107 vs. 2.36 × 106 gc/L, respectively), suggesting underreporting during the first wave, and highlighting the positive effect of vaccination during the second. To the best of our knowledge, this is the first study that simultaneously and systematically analyzed surface water and wastewater over a prolonged period, the effect of precipitations were considered for the variations in the concentrations, and the findings compared with epidemiological information. Environmental surveillance was demonstrated to be a great tool to obtain valuable information about the circulation patterns of SARS-CoV-2, especially under resource constraints to massively test the population, thus, underreporting cases. Furthermore, the methodology employed herein can be easily expanded to the community-level surveillance of other pathogens excreted in urine and feces, encompassing viruses, bacteria, and protozoa.
Tracking SARS-CoV-2 in rivers as a tool for epidemiological surveillance.
(2022) Maidana-Kulesza, María Noel; Poma, Hugo Ramiro; Sanguino-Jorquera, Diego Gastón; Reyes, Sarita Isabel; Del Milagro Said-Adamo, María; Mainardi-Remis, Juan Martín; Gutiérrez-Cacciabue, Dolores; Cristóbal, Héctor Antonio; Cruz, Mercedes Cecilia; Aparicio González, Mónica; Rajal, Verónica Beatriz
The aim of this work was to evaluate if rivers could be used for SARS-CoV-2 surveillance. Five sampling points from three rivers (AR-1 and AR-2 in Arenales River, MR-1 and MR-2 in Mojotoro River, and CR in La Caldera River) from Salta (Argentina), two of them receiving discharges from wastewater plants (WWTP), were monitored from July to December 2020. Fifteen water samples from each point (75 in total) were collected and characterized physico-chemically and microbiologically and SARS-CoV-2 was quantified by RT-qPCR. Also, two targets linked to human contributions, human polyomavirus (HPyV) and RNase P, were quantified and used to normalize SARS-CoV-2 concentration, which was compared to reported COVID-19 cases. Statistical analyses allowed us to verify the correlation between SARS-CoV-2 and the concentration of fecal indicator bacteria (FIB), as well as to find similarities and differences between sampling points. La Caldera River showed the best water quality; FIBs were within acceptable limits for recreational activities. Mojotoro River's water quality was not affected by the northern WWTP of the city. Instead, Arenales River presented the poorest water quality; at AR-2 was negatively affected by the discharges of the southern WWTP, which contributed to significant increase of fecal contamination. SARS-CoV-2 was found in about half of samples in low concentrations in La Caldera and Mojotoro Rivers, while it was high and persistent in Arenales River. No human tracers were detected in CR, only HPyV was found in MR-1, MR-2 and AR-1, and both were quantified in AR-2. The experimental and normalized viral concentrations strongly correlated with reported COVID-19 cases; thus, Arenales River at AR-2 reflected the epidemiological situation of the city. This is the first study showing the dynamic of SARS-CoV-2 concentration in an urban river highly impacted by wastewater and proved that can be used for SARS-CoV-2 surveillance to support health authorities.