Bacteria In Water Samples Research Articles

Relationships between fecal indicator abundance in water and sand and the presence of pathogenic genes in sand of recreational beaches.

For decades, the risk of exposure to infectious diseases in recreational beaches has been evaluated through the quantification of fecal indicator bacteria in water samples using culture methods. The analyses of sand samples have recently been developed as a complement to the monitoring of recreational waters in beach quality assessments. The growing use of molecular techniques for environmental monitoring allows for the rapid detection of pathogenic genes, thus providing more accurate information regarding the health risk of exposure to contaminated sand. The aim of this work was to determine the relationship between the fecal indicators abundance in water and sand and the presence of Shiga toxin-producer Escherichia coli (STEC) in sand by analyzing samples from touristic beaches using culture-dependent (fecal coliforms assay) and culture-independent (real-time PCR of stx1, stx2, and eae genes) techniques. We found a high concentration of coliform bacteria in water and sand in several beaches in eastern Uruguay, with different levels of sanitation networks and levels of urbanization. The presence of STEC virulence genes (mainly stx1) was confirmed in 8 out of 20 sand samples. The recreational use of sandy beaches may imply a risk to the health of its users, especially near streams and creek outflows, thus highlighting the need of monitoring sand bacteriological quality and pathogens using molecular tools.

Impedimetric Gram-Positive Bacteria Biosensor Using Vancomycin-Coated Silica Nanoparticles with a Gold Nanocluster-Deposited Electrode.

We introduce a swift, label-free electrochemical biosensor designed for the precise on-site detection of Gram-positive bacteria via electrochemical impedance spectroscopy. The biosensor was prepared by electroplating the electrode surface with gold nanoclusters (AuNCs) on the gold-interdigitated wave-shaped electrode with a printed circuit board (Au-PCB) electrode, which plays a role in cost-effective and promising lab-on-a-chip microsystems and integrated biosensing systems. This was followed by the application of silica nanoparticle-modified vancomycin (SiNPs-VAN) that binds to Gram-positive bacteria and facilitates their detection on the AuNC-coated surface. The biosensor demonstrated remarkable sensitivity and specificity. It could detect as few as 102 colony-forming units (CFU)/mL of Staphylococcus aureus, 101 CFU/mL of Bacillus cereus, and 102 CFU/mL of Micrococcus luteus within 20 min. Additionally, SiNPs-VAN is also known for its high stability, low cost, and ease of preparation. It is effective in identifying Gram-positive bacteria in water samples across a concentration range of 102-105 CFU/mL and shows selective identification of Gram-positive bacteria with minimal interference from Gram-negative bacteria like Escherichia coli. The ability of the biosensor to quantify Gram-positive bacteria aligns well with the results obtained from the quantitative real-time polymerase chain reaction (qRT-PCR). These findings highlight the potential of electrochemical biosensors for the detection of pathogens and other biological entities, marking a significant advancement in this field.

The impact of DNA extraction on the quantification of Legionella, with implications for ecological studies.

Monitoring the levels of opportunistic pathogens in drinking water is important to plan interventions and understand the ecological niches that allow them to proliferate. Quantitative PCR is an established alternative to culture methods that can provide a faster, higher-throughput, and more precise enumeration of the bacteria in water samples. However, PCR-based methods are still not routinely applied for Legionella monitoring, and techniques, such as DNA extraction, differ notably between laboratories. Here, we quantify the impact that DNA extraction methods had on downstream PCR quantification and community sequencing. Through a community science campaign, we collected 50 water samples and corresponding shower hoses, and compared two commonly used DNA extraction methodologies to the same biofilm and water phase samples. The two methods showed clearly different extraction efficacies, which were reflected in both the quantity of DNA extracted and the concentrations of Legionella enumerated in both the matrices. Notably, one method resulted in higher enumeration in nearly all samples by about one order of magnitude and detected Legionella in 21 samples that remained undetected by the other method. 16S rRNA amplicon sequencing revealed that the relative abundance of individual taxa, including sequence variants of Legionella, significantly varied depending on the extraction method employed. Given the implications of these findings, we advocate for improvement in documentation of the performance of DNA extraction methods used in drinking water to detect and quantify Legionella, and characterize the associated microbial community.IMPORTANCEMonitoring for the presence of the waterborne opportunistic pathogen Legionella is important to assess the risk of infection and plan remediation actions. While monitoring is traditionally carried on through cultivation, there is an ever-increasing demand for rapid and high-throughput molecular-based approaches for Legionella detection. This paper provides valuable insights on how DNA extraction affects downstream molecular analysis such as the quantification of Legionella through droplet digital PCR and the characterization of natural microbial communities through sequencing analysis. We analyze the results from a risk-assessment, legislative, and ecological perspective, showing how initial DNA processing is an important step to take into account when shifting to molecular-based routine monitoring and discuss the central role of consistent and detailed reporting of the methods used.

Drinking Water Sources Feasibility Test Based On Escherichia Coli As an Indicator Of Pollutant In Sultan Village Stunting Locus Of

Introduction: Water quality parameters are indicated by the presence of E. coli bacteria. These bacteria come from human feces, warm-blooded animals, and non-fecal coliforms. Decree of the Health Minister of the Republic of Indonesia Number 907/MENKES/VII/2002 concerning requirements and supervision of drinking water quality states that good drinking water has a zero total coliform and fecal coliform. Methods: This research uses a descriptive approach with a cross-sectional design. It aims to determine the quality of water sources in Sulkatan village. Ten (10) water sources were used as the samples using total sampling method. The collected samples were then taken to the laboratory to be tested with a series of MPN tests Results and Discussion: The results show that the amount of Escherichia coli bacteria in water samples in Sulkatan Village is 0MPN/100 ml. It is owing to the location of the water source that is far from industrial activities, household waste and residential areas. Conclusion: The quality of the tested well-water samples is good and within normal limits in accordance with the Decree of the Health Minister of the Republic of Indonesia Number 907/MENKES/VII/2002

Metagenomics analysis of water samples collected from the Yamuna River of Agra city, India.

Yamuna River water in Agra city of India is contaminated with toxic pollutants, including heavy metals that cause damage to the environment and human health. At present, the direct use of river water for drinking purposes and household activities lead to the direct exposure of society to the contaminants. In this study, Yamuna River water samples were collected from three different sites in Agra city during the monsoon, summer, and winter seasons. The physico-chemical parameters were estimated along with heavy metals. In physico-chemical parameter, the values found were mostly above the permissible limits. The results water samples contain high levels of cadmium, chromium, lead, and nickel above the desirable levels in most cases. The metagenomic analysis revealed that Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, and Planctobacteria were the most abundant phyla with a relative abundance of 61%, 9.34%, 5.23%, 4.64%, and 4.3%, respectively. The Comamonadaceae, the most abundant family consists of the genera involved in hydrogen oxidation, iron reduction, degraders of polycyclic aromatic hydrocarbons, and fermentation. The presence of Pseudomonas, Nitrosomonas sp., Thauera humireducens and Dechloromonas denitrificans (decomposition of sewage and organic matter) and Pseudomonas aeruginosa indicates the presence of heavy metal degrading bacteria in water sample. Functional prediction showed the presence of genes responsible for different metabolic pathways that could help developing new bioremediation strategies. The study concludes the status of water contamination, the presence of complex microbial community and suggests the futuristic use and their role in bioremediation.

Genomic characterization of a WHO critical priority isolate Enterobacter kobei ST2070 harboring OXA-10, KPC-2, and CTX-M-12 recovered from a water irrigation channel in Ecuador

The discharge of untreated or partially treated wastewater can have detrimental impacts on the quality of water bodies, posing a significant threat to public health and the environment. In Ecuador, previous research indicates a high prevalence of antimicrobial resistant (AMR) bacteria in surface waters affected by human activities, including irrigation channels. In this study, we analyzed sediment samples collected from an irrigation channel utilized for agricultural purposes in northern Ecuador, using microbiological techniques and whole-genome sequencing (WGS). Our investigation revealed the first documented occurrence of E. kobei in Ecuador and the initial report of environmental E. kobei ST2070. Furthermore, we identified the coexistence of OXA-10-type class D β-lactamase and KPC-2-type class A β-lactamase in the E. kobei isolate (UTA41), representing the first report of such a phenomenon in this species. Additionally, we detected various antibiotic resistance genes in the E. kobei UTA41 isolate, including blaCTX-M-12, fosA, aac(6′)-lb, sul2, msr(E), and mph(A), as well as virulence genes such as bacterial efflux pump and siderophore biosynthesis genes. We also identified two intact prophage regions (Entero_186 and Klebsi_phiKO2) in the isolate. Our study presents the first evidence of E. kobei isolate containing two carbapenemase-encoding genes in environmental samples from Latin America. This finding indicates the potential spread of critical-priority bacteria in water samples originating from anthropogenic sources, such as urban wastewater discharges and livestock facilities.

Effect of some physicochemical parameters on the decay rate of enteric bacteria isolated from River Owena, Nigeria

The significance of water in public health cannot be overemphasized. In Nigeria, many people living along the courses of water bodies still source and drink from the rivers and streams. There is, therefore, the need to determine the load of contamination and effect of pH and salinity on the decay rate of enteric bacteria in water samples from River Owena, Owena, Nigeria, in order to develop adequate water quality management. Water samples from River Owena were collected from three sampling points (inflow, middle course and the outflow) along the River Owena, Nigeria. The load of enteric bacteria in the water samples was enumerated using membrane filtration technique. The physicochemical parameters of the water samples were determined using standard methods. The incidence and prevalence of gastroenteritis in the community around River Owena was determined using a structured questionnaire. Microcosm studies were used to determine the decay rate of enteric bacteria at varying salinity and pH. Canonical correlation analysis was used to describe the relationship between the load of enteric bacteria and the incidence and prevalence of gastroenteritis in the community around River Owena. The incidence and prevalence of gastroenteritis in the community around River Owena were estimated to be 0.75 and 0.51, respectively. Escherichia coli had positive relationships with incidence (r = 0.76) and prevalence (r = 0.65). Similarly, faecal coliforms had positive relationships with incidence (r = 0.82) and prevalence of gastroenteritis (r = 0.67), while enterococci showed positive relationship with incidence (r = 0.59) and prevalence of gastroenteritis (r = 0.87). Increase in pH and salinity increased the decay rate of enteric bacteria thereby reducing the growth of enteric bacteria, the optimum pH for the growth and survival of enteric bacteria ranged between pH 5.0 and pH 7.0. The optimum salinity for the growth of enteric bacteria isolated in water samples from River Owena ranged between 10 and 50% salinity. Findings revealed high levels of faecal contamination at the different representative monitoring points on River Owena, pH and salinity influenced the load and decay rate of enteric bacteria in water from River Owena.

Virulence and Antimicrobial Resistance of Escherichia Coli Strains Isolated from The Water of The Amazon River, State of Amapá

Objective: We investigated the identification of E. coli strains in water samples from the Amazon River in the state of Amapá to determine the antimicrobial susceptibility profile and verify the presence of virulence factors and resistance genes. Reference theoretical: Antimicrobial resistance is a global public health concern, and the presence of resistant bacteria in water samples represents an additional risk for the spread of these microorganisms, with great impact on society in general, especially after the discovery of pathogenic strains of Escherichia coli. Method: The bacterial isolates were submitted to the technique of isolation of colonies in selective medium and identification by biochemical tests. Isolates identified as Escherichia coli were submitted to the antimicrobial sensitivity test and the polymerase chain reaction (PCR) technique to search for virulence genes and drug resistance. Results and conclusion: The results showed that the strains of E. coli isolated from the water samples of the Amazon River showed high rates of antimicrobial resistance. In addition, virulence gene markers were detected: eagg, eaeA, stx1, stx2, as well as resistance markers: qnrB and qnrS. Index of resistance to multiple antimicrobials MARI ranged from 0.1 to 0.6. All collection sites of water isolates has the presence of strains with multiresistance. Research implications: This study revealed the importance of monitoring water quality and implementing control measures to prevent the spread of resistant and potentially pathogenic bacteria. Originality/value: The research highlights the importance of implementing policies aimed at conserving Brazil's natural resources.

Multidrug-Resistant Enteric Bacteria in the Water Sources of Kalgo Metropolis, Nigeria

The high incidence of diseases, such as diarrhoea, typhoid fever, cholera, and bacillary dysentery among the populace, especially in remote and developing areas, has been traced to the domestic use of contaminated water. This study aimed to isolate enteric bacteria in major drinking water sources situated within the Kalgo metropolis, Nigeria. Three water samples were aseptically collected in triplicates from three different areas of the city. After serial dilution, the samples were inoculated on nutrient agar and each sample's total viable bacterial count was taken. The enteric bacteria were isolated and identified using standard protocols. The isolates were subjected to antibiotic sensitivity test using the Kirby Bauer disk diffusion method. The inhibition zones were measured in millimeters(mm). Seven (7) different species of bacteria were isolated from the collected water samples.The isolated organisms included Shigella spp., Serratia spp., Klebsiella spp., Escherichia coli, Proteus spp., Yersinia spp., and Salmonella spp. Among these bacterial isolates, E. coli and Salmonella spp.were found to have the highest frequency of 29.63% and 25.93%, respectively. While, Serratia spp.had the lowest frequency of 3.9%. The sensitivity profile showed that E. coli, Salmonella spp.,Klebsiella spp., Shigella spp., and Serratia spp. were resistant to ampicillin. In contrast, Proteus spp. and Yersinia spp. showed high and intermediate susceptibility, respectively.The presence of multidrug-resistant enteric bacteria in water samples suggests the need to improve water quality through its assessment and treatment before use.

Isolation and Characterization of Heavy Metals Resistant Bacteria in Water Samples from Mambilla Artisanal Mining Site, Nguroje, Taraba State

Isolation and Characterization of Heavy Metals Resistant Bacteria in Water Samples from Mambilla Artisanal Mining Site, Nguroje, Taraba State

Unveiling the pollution of bacteria in water samples through optic sensor

This study presents the development of a biomimetic optic sensor for the detection of Enterococcus faecalis, a common fecal contaminant found in drinking water. The sensor utilizes a molecularly imprinted nanofilm, created by combining gold nanoparticles. Extensive characterization and analysis were conducted to evaluate the performance of the optic sensor, including kinetic, selectivity, reusability and real sample studies for real-time detection of Enterococcus faecalis. The results demonstrate that the optic sensor exhibits remarkable detection capabilities, offering a low detection limit of 6.6×103 cfu/mL and a high determination coefficient (R2 = 0.9886) within the Enterococcus faecalis concentration range of 5×104 – 1×108 cfu/mL. Importantly, the sensor proves effective not only in buffer solutions but also in water sample solutions, showcasing its practicality for real-world applications. Based on these findings, it can be concluded that the developed optic sensor shows promising potential for the detection of other bacteria, offering a cost-effective solution with enhanced sensitivity. Its versatility extends across diverse fields, including environmental monitoring and medical diagnosis. With its impressive performance, the optic sensor represents a valuable tool for ensuring water safety and advancing bacterial detection technologies.

Rapid detection of ESKAPE and enteric bacteria using tapered dielectrophoresis and their presence in urban water cycle

ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) and enteric bacteria Shigella dysenteriae, Salmonella typhimurium and Escherichia Coli have been causing increasing nosocomial infections worldwide, contributing to high mortality and morbidity in surgical wards. This study attempts to investigate the feasibility of dieletrophoresis (DEP) electrode in detecting both ESKAPE and enteric bacteria in water samples. The detection is based on the bacteria's response to the non-uniform electric field in micro tapered DEP electrode and microfluidic chamber. Responses of each bacterium were recorded by varying the frequency of sinusoidal 6 voltage (peak to peak) from 10 to 13,000 kHz. Utilising the unique electrokinetic responses of each bacterium, the performance of DEP application is assessed in detecting the ESKAPE and enteric bacteria from samples within the urban water cycle, i.e., wastewater, river, runoff, and treated water from an urbanised developed area. The positive (PDEP), negative (NDEP) and transitional, (denote as the crossover frequency fx0) responses for each bacterium were consistently determined, spanning between 52.3 and 12,000 kHz. DEP technique was successfully able to detect ESKAPE and enteric bacteria from water samples, where water from the river proved to be the most microbially contaminated in urban water cycle.

Molecular identification of a Pseudomonas putida strain isolated from Machángara river (Quito-Ecuador) tolerant to carbamazepine

Carbamazepine is a molecule used to treat specific pathologies; however, it has become an emerging contaminant that is dangerous to the environment. In marine species and humans, it causes cytotoxicity, genotoxicity, reproductive disorders, and infertility. Thus, this pollutant has been subjected to conventional wastewater treatment, achieving low purification. In Ecuador, only some studies are related to emerging contaminants, and these show quantification but not treatment. Therefore, the implementation of biological techniques is necessary. In this sense, the research aimed to identify a bacteria in water samples from the Machangara River with carbamazepine tolerance. Morphological, biochemical, and molecular characteristics identified bacteria. The results indicated the presence of several microorganisms, including molecularly identified Pseudomonas putida. This was tolerant to carbamazepine concentrations of 15, 50, and 100 mg/L, with higher growth at the first concentration. This information can be valuable in wastewater treatment investigations. Keywords: carbamazepine, degradation, Machangara river, Pseudomonas putida.

The efficacy of solar disinfection on cistern water in Anguilla under emergencies such as hurricanes

Background: This study examined the effectiveness of solar water disinfection (SODIS) in removing coliform bacteria from water sources in Anguilla after hurricanes. Aims and Objectives: The objective of this study was to assess the efficacy of SODIS as a low-cost and accessible method for water disinfection in post-disaster scenarios, explicitly focusing on the reduction of coliform bacteria in water samples collected from various cisterns. Materials and Methods: Water samples were collected from different cisterns and tested for the presence of Escherichia coli and total coliforms using filter and plate methods. The samples were divided into three groups: Exposed to 48 h of sunlight, kept in the dark as a control, or tested immediately after collection. The effectiveness of SODIS treatment was evaluated by comparing the coliform bacteria levels before and after exposure to sunlight. Results: Results showed a significant reduction in coliform bacteria levels in the samples exposed to sunlight. Coliform colonies decreased from 724 in the initial samples to three colonies after SODIS treatment. Complete eradication was not achieved in all samples, but a notable decrease was observed in those with initial coliform bacteria. Conclusion: These findings contribute valuable data supporting the efficacy of SODIS as a low-cost and accessible method for water disinfection in post-disaster scenarios. Further, research and improvements are necessary to optimize SODIS methods for cistern water treatment in challenging post-disaster contexts. Continuous exposure to bright and clear sunlight for 48 h may lead to a more substantial reduction in coliform bacteria. However, it is essential to acknowledge that post-hurricane situations rarely offer ideal weather conditions.

Detection and Quantification of Antimicrobial-Resistant Cells in Aquatic Environments by Bioorthogonal Noncanonical Amino Acid Tagging.

Aquatic environments are important reservoirs of antibiotic wastes, antibiotic resistance genes, and bacteria, enabling the persistence and proliferation of antibiotic resistance in different bacterial populations. To prevent the spread of antibiotic resistance, effective approaches to detect antimicrobial susceptibility in aquatic environments are highly desired. In this work, we adopt a metabolism-based bioorthogonal noncanonical amino acid tagging (BONCAT) method to detect, visualize, and quantify active antimicrobial-resistant bacteria in water samples by exploiting the differences in bacterial metabolic responses to antibiotics. The BONCAT approach can be applied to rapidly detect bacterial resistance to multiple antibiotics within 20 min of incubation, regardless of whether they act on proteins or DNA. In addition, the combination of BONCAT with the microscope enables the intuitive characterization of antibiotic-resistant bacteria in mixed systems at single-cell resolution. Furthermore, BONCAT coupled with flow cytometry exhibits good performance in determining bacterial resistance ratios to chloramphenicol and population heterogeneity in hospital wastewater samples. In addition, this approach is also effective in detecting antibiotic-resistant bacteria in natural water samples. Therefore, such a simple, fast, and efficient BONCAT-based approach will be valuable in monitoring the increase and spread of antibiotic resistance within natural and engineered aquatic environments.

Foldscope: Increasing Science Accessibility Worldwide

Abstract:Foldscope Instruments, Inc. creates and distributes low-cost, high-quality scientific tools to communities around the world to help advance education, research, and medical diagnostics. The Foldscope—a high-quality microscope created for less than a dollar in parts—was created in 2015. To date, the Foldscope has reached 1.6 million people worldwide in over 160 countries. A few notable uses for the Foldscope include identification of microscopic eggs of agricultural pests in India, creation of a catalog of the biodiversity of soil arthropods in the Amazon, detection of fake currency and medicine, following toxic blooms, detection of bacteria in water samples, and mapping of pollen diversity in a city landscape.

Rapid Detection of Gram-Positive and -Negative Bacteria in Water Samples Using Mannan-Binding Lectin-Based Visual Biosensor.

Waterborne bacterial infection is a health threat worldwide, making accurate and timely bacteria detection crucial to prevent waterborne disease outbreaks. Inspired by the intrinsic capability of mannan-binding lectin (MBL) in recognizing the pathogen-associated molecular patterns (PAMPs), a visual biosensor is developed here for the on-site detection of both Gram-positive and -negative bacteria. The biosensor was synthesized by immobilization of the MBL protein onto the blue carboxyl-functionalized polystyrene microparticles (PSM), which is then used in a two-step assay to detect bacterial cells in water samples. The first step involved a 20 min incubation following the MBL-PSM and calcium chloride solution addition to the samples. The second step was to add ethanol to the resultant blue mixture and observe the color change with the naked eye after 15 min. The biosensor had a binary (all-or-none) response, which in the presence of bacterial cells kept its blue color, while in their absence the color changed from blue to colorless. Testing the water samples spiked with four Gram-negative bacteria including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and two Gram-positive bacteria of Enterococcus faecalis and Staphylococcus aureus showed that the biosensor could detect all tested bacteria with a concentration as low as 101.5 CFU/ml. The performance of biosensor using the water samples from a water treatment plant also confirmed its capability to detect the pathogens in real-life water samples without the need for instrumentation.

Bacterial diversity analysis of freshwater sources for human use in rural areas of the tropical Andean region of Colombia

Potable water supply and sanitization in rural areas in developing countries are still inadequate. The main risk associated with unsafe drinking water is the infection with pathogenic microorganisms. Objective: In this study, we investigate the bacterial diversity and the potentially pathogenic bacteria in water samples from different points of distribution in three rural villages from the Andean region of Colombia. Methods: Illumina libraries for water samples were prepared and sequenced using 300 bp paired-end MiSeq protocol, the bioinformatic analyses were performed with Mothur pipeline and the phyloseq package in Rstudio. Results: The microbial community composition showed statistically significant differences according to the village and the sample origin. Alpha, Beta, and Gammaproteobacteria were the dominant class detected in all water samples. The most relevant pathogenic genera detected in the surface were Legionella, Mycobacterium, Yersinia, Burkholderia, and Rickettsia. In the tap water samples, potential pathogens like Streptococcus, Staphylococcus, Corynebacterium, Nocardia, and Escherichia/Shigella were detected.

Antibiotics resistance in pathogenic bacteria isolated from water and sediment around the floating fish farms in the Nha Trang bay

To assess the impact of antibiotic use in aquaculture in Nha Trang bay, we conducted this study with the aim of assessing antibiotic resistance of opportunistic pathogenic bacteria isolated from water and sediment around shrimp/fish cages in the Nha Trang bay. 109 strains of Vibrio, Salmonella-Shigella and Aeromonas groups were isolated in the surrounding environment of farming areas in Dam Bay and Hon Mieu. Antimicrobial resistance test of these 109 strains showed that in the water environment in Dam Bay, TET (96.6%) and NIT (92.5%) were the two antibiotics with the highest rates of resistant bacteria while no bacteria were resistant to RIF. All 5 types of antibiotics had a statistically insignificant percentage of antibiotic-resistant bacteria in water samples at Hon Mieu, ranging from 33.3% to 68.9%. Also in the water environment, the rate of antibiotic-resistant bacteria in Dam Bay was not influenced by the distance to the cages (42.5–66.6%). Meanwhile, in Hon Mieu, the highest rate of resistant bacteria was observed at the distance of 200 m (100%) away from cages and the lowest rate at the distance of 100 m (20%). In the sediment environment around the cages, both the Dam Bay and Hon Mieu farming areas showed the highest rates of antibiotic-resistant bacteria against TET, NIF and RIF had the lowest rate of resistant bacteria. Among the total of 109 strains tested for antibiotic resistance, 2 strains labeled TCBS_HM200 m and SS_HM200 m were found to be resistant to all 5 tested antibiotics. These two strains were respectively identified as Vibrio harveyi and Oceanimonas sp.

Evaluation of the occurrence of pathogenic free-living amoeba and bacteria in 20 public indoor swimming pool facilities.

Recently, indoor swimming pool activities have increased to promote health‐enhancing physical activities, which require establishing suitable protocols for disinfection and water quality control. Normally, the assessment of the microbial quality of the water in the pools only considers the presence of different bacteria. However, other less frequent but more resistant pathogens, such as free‐living amoebas (FLA), are not contemplated in both existing recommendation and research activities. FLA represent a relevant human health risk, not only due to their pathogenicity but also due to the ability to act as vehicles of other pathogens, such as bacteria. Therefore, this work aimed to study the physicochemical characteristics and the occurrence of potentially pathogenic FLA and bacteria in water samples from 20 public indoor swimming facilities in Northern Portugal. Our results showed that some swimming pools presented levels of pH, free chlorine, and conductivity out of the recommended limits. Pathogenic FLA species were detected in two of the facilities under study, where we also report the presence of both, FLA and pathogenic bacteria. Our findings evidence the need to assess the occurrence of FLA and their existence in the same environmental niche as pathogenic bacteria in swimming pool facilities worldwide and to establish recommendations to safeguard the health of the users.