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Waterborne diseases can have different origins, micro-organisms such as bacteria and parasites being the most important ones. In this study, two recreational aquatic environments were studied in the province of Salta, Argentina. Water samples collected from three different locations, two from a creek and one from the outlet of a thermal complex, were monitored at four time points. Physicochemical and microbiological characterization of each point was conducted, as well as a search for parasites and amebae. Parasites were identified through optical microscopy observations and free-living amebae (FLA) were isolated by spiking in Petri dishes followed by subsequent molecular identification. Water samples from the outlet of the thermal complex showed different physicochemical characteristics from those of the creek. Bacterial indicators of contamination were detected at all points; however, the creek water had a significantly higher concentration of Pseudomonas sp. Sporadically, creek samples exhibited Ascaris spp. eggs, Giardia sp. cysts, and ancylostomid eggs. The presence of FLA was observed in all samples, 15 of which were isolated and identified as Acanthamoeba sp., mostly belonging to the T4 genotype. Parasite surveillance in recreational aquatic environments is an important complement to traditional microbial indicators for assessing water quality. The identified parasites represent a potential health risk for people using these environments., (Copyright © 2023 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

In lentic water bodies as reservoirs occur eutrophication processes, originated mainly from human activities (i.e. agriculture, animal exploitation). This influx of nutrients in aquatic ecosystems could promote blooms of potentially toxic cyanobacteria. The purpose of this work is to detect the presence of cyanobacteria strains in water samples, using molecular techniques to help in preventive management of reservoirs dedicated to water purification. We used two molecular techniques to detect genes implied with the synthesis of hepatotoxic microcystins from potentially toxic cyanobacteria strains, and to evaluate the molecular diversity of cyanobacteria in water samples from two high-mountain reservoirs used for purification of drinking water for the metropolitan area of Medellin, Colombia. Between 2010-2011 collections of 12 water samples were taken and DNA extraction together with PCR and DGGE analyses where carried out. We amplified 22 sequences between 250-300bp of the genes mcyA and mcyE, and these sequences were related with several strains and cyanobacteria genera accessions from NCBI-GenBank databases. Moreover, sequence amplifications of the 16S small ribosomal RNA subunit - 16S rRNA- between 400-800bp were also performed in order to use them for the DGGE technique. The amplification products of DGGE were set in polyacrilamide gel with posterior denaturing electrophoresis, and the scanned images of the gel bands were analysed with the software GelCompar II. For Riogrande II and La Fe reservoirs we found 35 and 30 different DGGE bands, respectively, as a measurement of molecular diversity in these artificial ecosystems. Here, we demonstrated the utility of two molecular techniques for the detection of genes associated with toxicity and molecular diversity of cyanobacteria in reservoirs destined for drinking water in urban centers. We recommend strongly following with periodically molecular biology studies in these ecosystems combined with limnological and ecological data, as new tools for management of plants of water purification and for the prevention of potentially public health concerns.

Introduction: Antimicrobial resistance is one of the biggest problems facing global public health. The emergence of resistant clinical and environmental strains worsens the situation. Among the microorganisms with antimicrobial resistance, Escherichia coil species stands out due to its dual role as fecal contamination indicator and pathogen., Objectives: To isolate and identify Escherichia coil isolates from water samples from polluted rivers located in La Habana, and to determine their antimicrobial in vitro susceptibility., Methods: One hundred thirteen isolates of coliform bacteria isolated from 10 sampling stations in the capital's urban areas near Almendares, Quibú and Luyanó rivers were studied in the period of February 2008 to June 2010. The identification of isolates, the determination of antimicrobial susceptibility and the search for extended-spectrum beta-lactamase were all performed using VITEK automated method., Results: One hundred thirteen environmental strains of Escherichia coli were identified. It showed that 23% of the isolates were resistant to at least one of the tested antimicrobials. The highest percentages of resistance were observed to ampicilline, sulfamethoxazole-trimethoprim and ciprofloxacin., Conclusions: The presence of E. coil isolates with multiple antimicrobial resistances in these rivers clearly indicates the biological risk involving the use of their waters.

Objective: Determining the frequency of pesticide use in agricultural, pig and poultry production to understand its influence on water resources in the village of Monterredondo in the municipality of San Pedro de Los Milagros (Antioquia) and diagnosing its quality., Methods: 100 % of the households in the village were surveyed regarding chemical use. Physicochemical and microbiological analysis of three water samples was carried out in the Universidad de Antioquia's Environmental Engineering laboratory using standardised methods., Results: The Hato stream was contaminated by 1,600 x 103 NMP/100ml coliforms and 220 x 10 NMP/100 ml E. coli. The Fray Juana stream had 1,600 x 103 NMP/100ml coliform contamination. Water sources were also contaminated by the use of pesticides such as Lorsban (chlorpyriphs), Burst (chlorpyriphs), Whip (chlorpyriphs), Neguvon (metriphonate) and Furadan (carbophuran) and insecticides like Ganabaño (cypermethryn) and disinfectants and Limpido (6 % sodium hypochlorite)., Conclusion: Agricultural, pig and poultry production in the village has been producing a negative impact on water resources due to its reduced availability and pollution. The water from the samples analysed here was not suitable for human consumption.

The introduction of antibiotic-resistant bacteria to the environment, affects its hygienic-sanitary quality. The objective of this work is to study the prevalence and the antibiotic resistance patterns of enterococci species isolated from Bahía Blanca estuarine waters. One hundred and three isolates were biochemically identified as Enterococcus spp. The diffusion technique was implemented, by using disks of: vancomycin (Van 30 microg), gentamicin (GenH 120 microg), streptomycin (StrH 300 microg), teicoplanin (T 30 microg), ampicillin (Am 10 microg) and ciprofloxacin (CIP 5 microg) according to the Clinical and Laboratory Standards Institute. Seven Enterococcus species were identified, being Enterococcus faecium and Enterococcus faecalis the most frequent. High level resistance to aminoglycosides was shown by 1.9% of the enterococci whereas 12.6% of the isolates were resistant to CIP. No isolates showed simultaneous resistance to StrH and GenH. Neither resistance to glycopeptides nor to Am was detected. Thirty four per cent of the isolates exhibited susceptibility to all antibiotics tested. Surveillance studies on antimicrobial resistance are usually based upon microorganisms isolated from clinical samples. The findings of this work constitute relevant data for the control of resistant strains, which were believed to be circumscribed to the hospital environment, but are also widespread in the natural sites.

Bacterial diversity in a fluidized bed bioreactor (FBR) treating gasoline-contaminated groundwater. The main objective of this research project was to determine the bacterial diversity during the process of bioremediation of water contaminated with gasoline in a fluidized bed reactor at Mayagüez, PR. Isolation and characterization of bacterial populations from the bioremediation system was performed on R2A medium. Morphological tests included cellular and colonial shape and reaction to Gram coloration. Physiological properties were determined by using carbon utilization profiles (Biolog) and by the ability of axenic cultures to use gasoline as the sole carbon source. Molecular characterization was performed by BOX-PCR and 16S rDNA sequence analysis (ARDRA). From a total of 162 distinctive isolates, 75% were gram-negative bacilli, 19% gram-positive bacilli, 5% gram-negative cocci and 1% gram-positive cocci. The 162 axenic cultures corresponded to 90 different genetic groups; 53% of which included strains with growth in gasoline as sole carbon source. The 86 strains capable of growing in gasoline corresponded to 52 different amplification patterns in BOX-PCR; which were not metabolically related (Biolog system). The high degree of microbial diversity in the FBR allowed efficient and stable hydrocarbon removal throughout the operation of the system.

We measured microcystin levels in water of the Metropolitan Area of Costa Rica by competitive inhibition ELISA and we quantified total coliforms, fecal coliforms, Escherichia coli (by a Most Probable Number method) and aerobic count. We wanted to identify any cyanotoxin correlation with these parameters, as a public health risk. We sampled in the rainy season of 2003 (April-October) and in the dry season of 2004 (February-March) (30 samples/season). We sampled pre-treated, semi-treated and treated water. Microcystin levels < 0.5 ppb were found in the rainy season (and > 0.5 ppb in the dry season). Dry season levels exceeded World Health Organization limits (1.0 ppb). Cyanotoxins occurred in the Tres Rios plant. We did not find a correlation between these microbiologic parameters of water quality and microcystin levels in water.

The objectives of the present study are to describe the clinics view of acute infectious gastroenteritis (GE) at the community, in primary and secondary attention health centers, with special references to viral aetiology (VIGE); to correlate with drinkable water and excrete treatment; to develop for the first time a fast diagnostic using electron microscopy in Río Cuarto, Córdoba, Argentina, considering the university and community collaboration in the viral diagnostic. It has been during one year, 122 cases of acute GE, over its clinics epidemiology and diagnostic aspects (1999-2000). With conventional laboratory methods, it has been determined the bacteria and micotic aetiology (NOVIGE); the virology diagnostic with electron microscopy; and the use of the statistics for the data analysis. The microbial findings has been: pathogenics bacteria (31.7%), fungus (17%), parasites (1.2%), rotavirus (16.4%), calicivirus (1.6%), adenovirus and coronavirus (1.6%). The clinics findings are presents like digestive and extra-digestive signs, separated in NOVIGE (and no-diagnosticated) and VIGE groups. The seasonal viral and no-viral distributions are present in fig. 5. There are statistics signification: the NOVIGE in summer period (49%) against the VIGE (12.5%) (p < 0.0003); the VIGE in winter period (87.5%) against the VIGE in summer period (12.5%) (p < 0.0003); the GE aetiology (VIGE and NOVIGE) in associated with age groups (p < 0.0003); the vomits preceding diarrhoea in VIGE was 58% and in NOVIGE (19.5%) (P < 0.001). It has been presented without significative differences all the clinics signs and laboratory examinations; the breeding signs for the younger 2 years group compared with the 2 years older; the age correlation (< and > 2 years) and season (winter-summer) with the 16% for the first in VIGE (62.5% rotavirus); the absence of health systems at the NOVIGE (70%) and with both (29%); and others epidemiology considerations of the sequence. With came to conclusion that in our city: 1. there are VIGE with signficative participation of rotavirus; 2. its distribution are winter and age group, also considering the other age groups and virosis; 3. the NOVIGE may difference at the clinic sign like vomit, between all the possible sintomatology; 4. the principal cause of diarrhoea and the no seasonal distribution are the NOVIGE; 5. there are not a strong relationship of diarrhoea by shortage environmental health in this study; 6. it's possible in Río Cuarto to made a fast and direct virology diagnostic using an electron microscopy.

Pollution due to urban-agricultural and urban-industrial activities, on the enzymatic activity of two microorganisms was evaluated. The zones under study are located in the Caltongo "embarcadero", in Xochimilco, D.F., and the basin of Lerma-Santiago river, State of Mexico. Nine and ten stations were established, respectively. Samples of water and sediment were taken, in order to determine their pH, salinity, organic matter, as well as the toxic effect produced on Escherichia coli beta-galactosidase activity and on Bacillus cereus hydrogenase activity. Fecal coliforms and anionic detergents were quantified on the water samples. A correlation analysis was applied to results of chemical variables and microbiotest performed. In Xochimilco were found six stations over 50% of inhibition of the enzymatic activities evaluated, in Lerma-Santiago were only four stations. The correlation coefficient found was between -0.95 and 0.53. In general, the zones under study showed a pollution degree and toxic effect moderate, as well as a minimum correlation between chemical variables and the response of microorganisms used as indicators.

There are no standards accepted by all the countries to fix top concentrations of microbiological indicators in recreational waters. Even now there is still a considerable discussion either in USA as in Europe. The universal application of a bacteriological quality criterion is hard due to several environmental factors that affect the relation between the indicator, the exposition and the health risks. Our purpose was to present a case study as an example of the influence of the climatic conditions in the application of the most known standards (Environmental Protection Agency of USA, Council of European Communities, World Organization of Health, and others from Canada, South Africa and Hong Kong). The pluvial rainfall increased the number of E. coli, thermotolerant coliforms (C Te), and total coliforms (CT) 6-10 fold, in comparison to the number registered during the steady-state conditions of the system. However, not all the standards included that factor. In Summer, hourly, daily and weekly variations were proved, therefore the standards that suggest fortnightly sampling frequencies would not be convenient in that system. Although the main source of variation was time, spatial variability was also detected. The percentage of E. coli among the C Te was very variable, but the average resulted low (26%) compared to the levels in temperate regions of other countries (> 90%). According to the directives proposed by the Commission of European Communities, the parameter has been changed (C Te for E. coli), but the standard has remained (2000/100 ml). Thus, the directive would be more permissive.

In this work, the serotypes of Salmonella genus polluting the waters of Lujan River, situated in the north east of the province of Buenos Aires, Argentina, were studied. A total of 690 samples of water were collected and analysed from February 1988 through December 1989, at three different sites. They were obtained according to the Moore technique and then preenriched in buffered peptone water and enriched in Rappaport-Vassiliadis Soya peptone broth was carried out. The isolations were realised in brilliant green-desoxycholate agar and bismuth sulphite agar and the presumptive colonies to be Salmonella were tested by the standard biochemical identification. Salmonella spp. was isolated in 434 samples (62.9%). The predominant serotype was S. Anatum, followed in a decreasing order by S. Montevideo, S. Newport and S. Bredeney. A large amount of serotypes that are isolated with very low frequency and very rarely in other hidric courses in the country were: S. Westhampton, S. Poona and S. Saintpaul were found.

Among 3 varieties of Xanthomonas campestris, the variety ocumo (X. campestris pv. ocumo), showed the greatest capacity for producing xanthan. This bacteria grows appropriately and produces this polysaccharide in a wide diversity of carbohydrate sources. However, this strain does not produce xanthan when the carbohydrate comes from lignocellulosic materials. The glucose syrup FAVEPRO was the carbon source that showed the best yield (23 g/l) with the greatest viscosity (7000 cps) of xanthan. The optimum production conditions in 1 L erlenmeyer flasks, with a working volume of 0.2 L and in a 14 L (stirred tank type bioreactor) with a working volume of 10 L, were the following: total sugar 5%, urea 0.05%, di-potassium hydrogen phosphate 0.5%, pH 7.5, inoculum 10%, temperature 30 degrees C, agitation 250-1000 rpm and aereation 0.3-1.0 vvm. This strain of X. campestris pv. ocumo was able to produce xanthan (10 g/l) in a culture medium based on a previously treated agricultural waste, called soluble acid extract of cassava bark. The viscosity of this medium increased up to 1500 cps.

When an ecosystem is disturbed, it reverts to an early successional state, characterized by changes in community structure and function, that can be anticipated as response to stress. The purpose of this paper was to check the effect of a disturbance caused by application of chemical compound (Copper Sulfate, to 100 micrograms L-1 granular of 92%) on the phytoplankton community in a pond located in Guaicaipuro, Edo. Miranda (Venezuela), and compare the diversity and composition of the community before and after the chemical application. An additional purpose was, to test the Odum's hypothesis about the community response to chemical stress. The chemical compound was apply in different random points to assure homogeneous distribution in the water body. Only one application of the chemical was used 6 hours after the first sample was taken. Dissolved oxygen in surface and depth were measured. In order to estimate the diversity and composition of phytoplankton community, samples were taken in 5 random points of the pond, until a 2 liter sample was completed in an intermediary basis, during 30 days in the beginning of rainy season, between june and july of 1994. Oxygen showed a maximum value at surface of 9.3 mg O2/L and minimal value at depth (2.3 mg O2/L). Species richness varied between 4 and 18. Phytoplankton community varied between 7.1 x 10(4) and 7.8 x 10(6) cel/L, and diversity index between 0.12 and 1.39. Oxygen, species richness and phytoplankton minimal values were noticed at the fifth day after chemical application. Before chemical application, phytoplankton community was dominated by filamentous microalgae, especially Chlorophyta. After the fifth day, this group decreased in abundance and species number. On the seventh day small-size Cyanobacteria became dominant, particularly Chroococcoid forms. The community reverted to an early stage of ecological succession. Since the ninth day, community showed the following abundance sequence: Chrysophyta, Pyrrophyta, Bacillariophyta, and Euglenophyta, with an increased species richness. At the end of the study period, filamentous Chlorophyta species appeared. These results support Odum's hypothesis.

The main objective was to determine the bacteriological quality of a shallow lake in the lower Salado River Basin (Bedetti, 31 degrees 40' S and 60 degrees 45' W). Seventy samples were tested by the most probable number (MPN) method, throughout three years. The number of thermotolerant coliforms was very variable: from 20 MPN/100 ml to 130,000 MPN/100 ml. These variations were mainly associated to the local rains (rs = 0.4853, p = 0.0001) and to the hydrometric level-h-(rs = 0.3835, p = 0.008). Statistically significant correlations between coliform bacteria and other variables (temperature, oxygen, pH, conductivity and transparency) were not found. The increase of coliforms associated to the increase of the hydrometric level indicates the presence of diffuse contamination sources. It was found that the rains affected the bacteriological quality, specially during the low water periods (h < 3.60). During the high water periods (h > 4.70) one of the main coliform contributor was represented by the incoming floating islans and aquatic macrophyte, from allochthonous fluvial systems. The coliform concentrations between the Bedetti lake and the Salado river were compared. The results show a better bacteriological quality of the lake (geometric average = 1,990/100 ml vs. 420/100 ml, n = 56) so that, connecting them by the construction of an artificial channel is not advisable.