Publicaciones

Agreement between methods using 4-Methylumberlifery1-B-glucuronice and conventional biochemical methods to identify E.coli.

Fecha Resumen Autores Publicación
1990-01-01 Agreement between methods using 4-Methylumberlifery1-B-glucuronice and conventional biochemical methods to identify E.coli. G.I. Ramírez Toro, H.A. Minnigh and Eva Rivera. 1994. Agreement between methods using 4-Methylumberlifery1-B-glucuronice and conventional biochemical methods to identify E.coli.Abstr. Ann.Mtgs ASM. Paper Q216.  

A low-cost community educational intervention to improve potable water quality and health

Fecha Resumen Autores Publicación
2008-10-14 Presentación Oral. XXXI Congreso Interamericano de Ingeniería Sanitaria y Ambiental. 1 Foro Interamericano sobre Servicios de Agua y Saneamiento. Santiago-Chile 12-15 de octubre de 2008. H. Minnigh, G. I. Ramírez, P. Hunter 2008  

Bacteriological Water Quality Indicators in Natural Water

Fecha Resumen Autores Publicación
1990-01-01 Presentación Oral Ramirez, G.I, Minnigh H.A, Troche F; Ramos Morales Larry & Rivera Matos, Odriel. 1997. Bacteriological Water Quality Indicators in Natural Water. III Regional AIDIS Congress for North America and the Caribbean. June 8-12,1997.  

Microbiological Indicators, Frank Pathogens and Disease in Small Potable Water System

Fecha Resumen Autores Publicación
2013-06-12 Presentación Oral H.Minnigh, G.I Ramírez, P. Hunter, D. Herson, D. Verville. 2008. (Oral Presentation). Microbiological Indicators, Frank Pathogens and Disease in Small Potable Water System. AWRA 2008 Annual Conference. New Orleans, Louisiana.  

Bacterial Indicators in Experimental Slow Sand Filters in Puerto Rico

Fecha Resumen Autores Publicación
2013-06-12 Presentación Oral W.O. Pipes, Minnigh H.A, Ramírez-Toro G.I., Rivera Mérida & Rivera Eva. 1993. Bacterial Indicators in Experimental Slow Sand Filters in Puerto Rico. Conference on Water Quality in the Wstern Hemisphere  

The Struggle to make water and health for rural America a priority; the case of PR

Fecha Resumen Autores Publicación
2013-06-05 Presentado Reunión de Sistemas Non-Prasa el 5 de junio de 2013 Dra. Graciela Ramírez  

Microbial Contaminants in Shellfish Harvesting Areas Puerto Rico

Fecha Resumen Autores Publicación
2013-09-19 AIMS In Puerto Rico oysters and clams are harvested from near-shore areas of different bays in the southwest and south of Puerto Rico and sold in local markets. During moderate to heavy rains surface waters feeding these growing and harvesting areas routinely receive effluents containing fecal waste from residential, municipal, agricultural and wildlife origins. These shellfish are harvested from areas where there is no shellfish sanitation program or controlled mariculture for this product. This surface water contamination was thought likely to contribute to the burden of shellfish-associated gastroenteritis. Little is actively being done to ensure the sanitary quality of shellfish being consumed on the island. There is a lack of trained laboratory workers to conduct surveys of shellfish culture areas, limited public or, more importantly food handlers’ awareness of the risks of consuming raw shellfish as well as an almost total lack of epidemiologic records specific to illness due to consumption of shellfish. We hypothesize that molluscan shellfish harvested from local surface waters pose a health risk for island residents and travelers visiting the island. We anticipate that the establishment of a shellfish sanitation program and the increased awareness of food-borne illnesses will reduce the incidence of shellfish-associated illness in Puerto Rico, as it has in other locations. This study was initiated to estimate the prevalence of enteric pathogens in molluscan shellfish harvested and sold locally to provide evidence of that contamination and to engender support for a shellfish sanitation program in Puerto Rico in agencies and, more importantly, among vendors. In addition, these data will help prioritize on-shore actions to reduce these inflows into waters where shellfish grow and are harvested. Other objectives were assessment of shellfish vendor and consumer knowledge of the risks posed by consuming raw shellfish and training of state, and federal workers in the design, and implementation of shellfish sanitation programs. Shellfish, mostly mangrove oysters (Crassostrea rhozophorea) and – in much smaller numbers – clams (Mercenaria mercenaria) are harvested from four areas in Puerto Rico; Boquerón Bay, Puerto Real, Santa Isabel and Jobos Bay. Most oysters come from and are sold adjacent to Boquerón Bay where we sampled 3 sites. The other sites had one station each. Clams are geographically more distributed but the beds are less abundant. The harvesting and sampling sites are shown at Figure 1. METHODS Standard sampling protocols developed by the Interstate Shellfish Sanitation Conference (ISSC) were used to conduct a survey of Puerto Rico’s four primary shellfish rearing areas. At each of the area sites water, sediment, and bivalves were sampled bimonthly and after five storm events during an 18 month period. Each matrix was analyzed for the detection of total coliform (TC), Thermotolerant coliforms (ThC), E. coli (Ec), Enterococcus spp., Salmonella spp., in bivalve, water and sediment samples and Hepatitis A virus and Norovirus in bivalve samples. For each sample site a single 1-L water sample, three approximately 30-gr sediment samples and approximately 15-50 animals were collected. Aliquots of all three matrices were analyzed. Oysters and clams were stomached and the slurry collected aseptically. Bacterial methods were according to Standard Methods and for viruses RNA was extracted from the bivalve’s stomach with a proteinase K based protocol and by means of the Biomeriux® Nuclisens EasyMag which is an apparatus that automatically performs RNA or DNA extraction. Later, real-time PCR was conducted on the samples with appropriate internal amplification positive control in each sample. RESULTS AND CONCLUSIONS A total of 72 pooled samples (15 individuals each) were tested for viruses and 15% of the samples were positive for the viruses tested. Norovirus GI and GII were both found as well Hepatites A. Bacterial concentrations found in the samples ranged from 15-25 CFU ThC/g, 15-25 CFU E. coli/g, and 30-145 Enterococci/g in bivalves; 30-875 CFU ThC/g, 250-550 CFU E. coli/g, and 30-145 Enterococci/g in sediments; and 60-1100 CFU ThC/ml, 60-1250 CFU E. coli/ml, and 14-23 Enterococci/ml in water. Data from this study suggests that water and sediment quality indicators correlate well with microbial occurrence in bivalves and that molluscs harvested from surface waters not specifically approved for shellfish harvesting pose a health risk for consumers. Surveys of vendors and customers showed very little understanding of the risks of consuming nor handling raw shellfish nor means to reduce those risks. Several educational activities focused on vendors and agency personnel and to garner support for the implementation of a shellfish sanitation program were conducted. Among these was an experiment to demonstrate preferences of customers – vendors had believed that consumers would not purchase iced shellfish – and a pilot mariculture program with oysters moved to cleaner waters is underway and will be reported. Ramírez G, K. Ballester, H.A. Minnigh, J. Levine. Presentado en 17th International Symposium on Health Related Water Microbiology WaterMicro 2013 Florianopolis. TL67. 15-20 de septiembre 2013.  

Which Faecal indictor organisms are indicators of health risk P.R

Fecha Resumen Autores Publicación
2013-09-19 AIMS The use of faecal indicator bacteria in the assurance of the safety of drinking water has a long and valuable history that extends for over a 100 years. Although ideally one would want to test water samples for the presence of pathogenic micro-organisms such pathogen detection can be very costly and time consuming. Faecal indictor bacteria are used because their presence is thought to indicate the presence of faecal material and, so the argument goes, if faecal material is present then there is a risk of faecal pathogens being present. In recent years confidence on faecal indicators as measures of drinking water safety has been dented by outbreaks of cryptosporidiosis and viral pathogens where such indicators were not detected. Nevertheless, indicator testing of drinking water remains one of the most commonly performed microbiological tests undertaken globally. The issue remains which of the three indicators listed above gives the most useful information. This paper reports on the outcome of three studies that used a variety of indicators to determine the relationship with illness with drinking water or the presence of pathogens in water. METHODS Data from three studies two of which have been reported in the literature. The first study was of self-reported diarrhoea in people living in households being supplied with drinking water from very small supplies (Risebro H et al. Risk of infectious intestinal disease in consumers drinking from private water supplies: A prospective cohort study. PLOS One 2012; 7(8): e42762). The second was a study of the presence of Cryptosporidium and Giardia in larger private water supplies (Kay D et al. The microbiological quality of seven large commercial private water supplies in the United Kingdom. J Water Hlth 2007; 5: 523-538). The third study was of the presence of Salmonella in small supplies in Puerto Rico. Data analysis was done in STATA version 11.2. For each study we calculated the association between indicator presence/counts with the presence or absence of the outcome variable using logistic regression analysis with robust standard errors to account for repeat samples from the same water source. Where appropriate, we adjusted for potential cofounding variables within the study. In addition we calculated the area under each Receiver operating characteristics (ROC) curve to determine which indicator was the best predictor in each context RESULTS For the Puerto Rico study we had 102 data points of which 57% were positive for Salmonella. Associations were controlled for whether the samples were from source water or tap water and period of sampling. The model with total coliform (Pseudo R2=0.235) and p=0.0055, thermo-tolerant coliforms (Pseudo R2=0.232) and p=0.0073, E. coli (Pseudo R2=0.310) and p=0.047, Enterococci (Pseudo R2=0.318) and p<0.0001. Enterococci had the highest area under the ROC (0.804) and this was significantly greater than those of the other indicators (p=0.015). By contrast for the UK Cryptosporidium study E. coli gave the highest area under the ROC for both Cryptosporidium (0.67) and Giardia (0.71) and in both cases this was statistically significant (P=0.001 and p=0.006). However, in neither case was the relationship between E. coli and pathogen presence strong. For the study of self-reported diarrhoea, as reported previously, Enterocococci were more strongly associated with prevalence than E. coli or Total coliforms. Where there was a strong association with enterococci the models for E. coli were re-run after exclusion of enterococci positives and there was no apparent trend between E. coli positive Enterococci negative samples and Salmonella presence or indeed illness. CONCLUSIONS There has quite appropriately been a shift towards Water Safety Plans and away from simple reliance microbiological testing. However, faecal indicator organisms still have great value in the assurance of drinking water safety, especially in small and very small systems which are less likely to have expert oversight. We have shown that faecal indicator bacteria are predictors of the presence of enteric pathogens in water and also are predictors of illness in children. The strongest evidence of value is in favour of Enterococci. Hunter.P, G. Ramírez, H.A. Minnigh, D. Kays. Presentado en 17th International Symposium on Health Related Water Microbiology WaterMicro 2013. TL74. 15-20 de septiembre de 2013.  

Ocurrence of Cryptosporidium and Other Frank Pathogens and Indicators in Small Rural Water System Waters in Puerto Rico

Fecha Resumen Autores Publicación
2013-11-05 Waters used as sources for five small potable water systems in Puerto Rico were sam-pled over a period of about 4 years. Samples were analyzed for total (TC) and thermo-tolerant (TC) coliforms, E. coli (Ec), enterococci (Ent), Salmonella (Salm), Cryptosporid-ium (Cryp) and Cyclospora as well as pH, turbidity. Distributed water was also ana-lyzed for free and total chlorine (FCl and TCl). In these systems the only difference be-tween raw and distributed water is chlorination. A subset of four systems was also analyzed for Bacteroides by molecular techniques in December, 2011. These data were generated to illustrate the incidence of Cryp in natural waters in Puerto Rico and as baseline data for treatments to be applied subsequently. For the normal indicators (TC, TTC, Ec & Ent), had arithmetic means of 1,300, 850, 500 and 460 CFU/ mL, respectively. Of 52 samples 18 were positive for Cryp and of these, only one was Salmonella negative and Cryp positive while 25 samples were Salm posi-tive and Cryp negative (McNemar’s test 4.707, p < 0.0001) suggesting a co-incidence of Salm and Cryp. Of 52 samples, as noted, 18 (35%) were positive for Cryp while 42 (81%) were positive for Salm. None of the 21 presumptive Cyclospora positives were verified. None of the distributed samples was Cryp positive. 0f the 94 distributed samples 31 (33%) were positive. Of the common indicators only TTC and Ec were sig-nificantly related to Salm and neither TCl nor FCl were related. Of the Bacteroides samples, only one was positive for the human specific marker. However, peafowl (3), chicken (3), cow (3), pig (4), dog (4), rabbit (5) and horse (1) droppings from the watersheds were collected and all the rabbit and one peafowl samples were positive for the human specific marker. Normalized, the peafowl sample was removed, so all rabbit and no other animal fecal samples were positive. All the rabbits were reported to be domesticated by residents. * Se prohibe el uso de fotografia e Información sin la autorización del Programa CECIA *Copyright CECIA Dra. Graciela Ramírez- Universidad Interamericana de Puerto Rico; Harvey Minnigh- Gabriella and Paul Rosenbaum Foundation; Michael Ryan- Drexel University Philadelphia; Presentado en 2013 Annual Water Resources Conferences- American Water Resources Association (AWRA)- Portland, Oregon- November 4-7,2013.  

The Role of attachment in the colonization and resistence of chlorine of fungi in potable water distribution systems.

Fecha Resumen Autores Publicación
1998-01-01 The Role of attachment in the colonization and resistence of chlorine of fungi in potable water distribution systems. Ramirez G.I, MInnigh H.A, Pipes, W.O & Roseinweig, W.D (1998). Eight International Symposium on Microbilogy Halifax, Canada.  

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