Waterborne Pathogens Research Articles

Combatting biofilms in potable water systems: A comprehensive overview to ensuring industrial water safety.

Biofilm formation in industrial potable water systems, encompassing applications such as drinking, emergency showers, firefighting and sanitary appliances, presents a multifaceted challenge that has significant implications for both equipment efficiency and human health. These microbial communities, comprised of bacteria, fungi and protozoa, adhere to surfaces and are embedded within an extracellular matrix, primarily of polysaccharide origin. The formation and persistence of these biofilms can lead to reduced system efficiency and potential health risks due to microbial-induced corrosion, contamination and waterborne pathogens. This review delves into the physicochemical and microbial factors promoting biofilm growth in these systems and elucidates contemporary strategies for their control and eradication. By harnessing advanced methodologies, including state-of-the-art filtration, disinfection techniques and predictive monitoring, stakeholders can proactively address biofilm-related challenges. The emphasis of this comprehensive overview is on the interdisciplinary nature of biofilm growth, combining insights from microbiology, engineering and water chemistry to pave the way for an integrative approach to ensuring consistent industrial water quality.

Emerging Applications of Nanobiosensors in Pathogen Detection in Water and Food.

Food and waterborne illnesses are still a major concern in health and food safety areas. Every year, almost 0.42 million and 2.2 million deaths related to food and waterborne illness are reported worldwide, respectively. In foodborne pathogens, bacteria such as Salmonella, Shiga-toxin producer Escherichia coli, Campylobacter, and Listeria monocytogenes are considered to be high-concern pathogens. High-concern waterborne pathogens are Vibrio cholerae, leptospirosis, Schistosoma mansoni, and Schistosima japonicum, among others. Despite the major efforts of food and water quality control to monitor the presence of these pathogens of concern in these kinds of sources, foodborne and waterborne illness occurrence is still high globally. For these reasons, the development of novel and faster pathogen-detection methods applicable to real-time surveillance strategies are required. Methods based on biosensor devices have emerged as novel tools for faster detection of food and water pathogens, in contrast to traditional methods that are usually time-consuming and are unsuitable for large-scale monitoring. Biosensor devices can be summarized as devices that use biochemical reactions with a biorecognition section (isolated enzymes, antibodies, tissues, genetic materials, or aptamers) to detect pathogens. In most cases, biosensors are based on the correlation of electrical, thermal, or optical signals in the presence of pathogen biomarkers. The application of nano and molecular technologies allows the identification of pathogens in a faster and high-sensibility manner, at extremely low-pathogen concentrations. In fact, the integration of gold, silver, iron, and magnetic nanoparticles (NP) in biosensors has demonstrated an improvement in their detection functionality. The present review summarizes the principal application of nanomaterials and biosensor-based devices for the detection of pathogens in food and water samples. Additionally, it highlights the improvement of biosensor devices through nanomaterials. Nanomaterials offer unique advantages for pathogen detection. The nanoscale and high specific surface area allows for more effective interaction with pathogenic agents, enhancing the sensitivity and selectivity of the biosensors. Finally, biosensors' capability to functionalize with specific molecules such as antibodies or nucleic acids facilitates the specific detection of the target pathogens.

Building Water Quality Commissioning in Healthcare Settings: Reducing Legionella and Water Contaminants Utilizing a Construction Scheduling Method

Construction activities in healthcare settings potentially expose building occupants to life-threatening waterborne pathogens, including Legionella. The lack of a building water quality commissioning (BWQC) process has been identified as a substantial construction risk factor associated with disease cases and deaths. A BWQC schedule method was developed as a technical note to address gaps between the construction, commissioning, and operation phases of work to establish water quality and safety for a building water distribution system. The BWQC schedule method enables healthcare organizations to meet commissioning criteria set forth in guidelines and regulatory requirements for implementing a water management program (WMP) prior to initiating patient care operations. The authors used Office Timeline® Pro+Edition V7.02, Office Timeline LLC, Bellevue WA 98004, USA to depict a Gantt chart as a BWQC schedule listing key project tasks and milestones of construction and water management activities. Design and construction professionals, in conjunction with healthcare organizations, should examine the BWQC construction schedule method and customize it for project-specific implementation. Additionally, building owners should consider incorporating the method into an organization’s construction policies for a standardized approach to BWQC practices.

Assessment of solar water disinfection enhancement with H2O2 and dissolved oxygen on inactivating different waterborne pathogens

Water scarcity has been growing for the last decades and one feasible solution for water-deprived areas is the storage and treatment of roof-harvested rainwater. Solar disinfection (SODIS) is a proven water treatment procedure, but several drawbacks still need assessing, such as increasing the output volume of treated water, reducing the treatment time and/or increasing the inactivation efficiency performance. In this study, the addition of low concentrations (1–5 mg/L) of H2O2 and/or the increment of dissolved oxygen (DO) has been tested at a pilot plant scale using a solar Compound Parabolic Collector photo-reactor with the aim of enhancing the disinfection efficiency of SODIS. Their performance has been assessed against a consortium of five pathogens normally found in rainwater: E. coli, E. faecalis, S. enteritidis, P. aeruginosa and MS2 bacteriophage. The addition of DO and/or H2O2 to solar photo-inactivation (SP-I) proved to enhance pathogens’ inactivation kinetics. Results have shown that O2 supply affects E. coli, P, aeruginosa and E. faecalis as their kinetic constants increase 1.48, 1.17 and 1.6 times, respectively. On the other hand, H2O2 addition enhances the inactivation of all pathogens. being the most noteworthy MS2 inactivation as > 5 Log Reduction Values (LRV) were reduced for all concentrations between 99% and 95% of the energy required for SP-I. Finally, the combination of both agents is also effective but can only be noted in E. faecalis inactivation, which is better than with only H2O2 addition. The findings obtained in this study show that from the perspective of implementing solar technologies in the field, the addition of DO sparging can be discarded due to a slightly enhanced disinfection performance, while the use of low H2O2 concentrations can be envisaged due to both, the enhancement of the disinfection performance and the competitive cost estimated (0.0025 €/L) in comparison with only SODIS (0.002 €/L).

C2 (Clinical Case) Complicated Sinusitis in an Adolescent Swimmer in the COVID-19 Pandemic: An Unexpected Microbial Player

Abstract Introduction/Background There are increasing reports of complicated sinusitis following post-pandemic viral surges. Streptococcus anginosus and Staphylococcus aureus (SA) are common causes. However, unusual pathogens may need to be considered in the face of inadequate therapeutic response. Case Description A previously healthy 13-year-old boy presented with fever, facial pain, and headache two weeks following presumed COVID-19 infection based on exposure history and symptoms. While recovering, he had been swimming daily and recalled inhaling pool water. On examination he was febrile with a tender mid-forehead swelling and left periorbital swelling without features of orbital cellulitis. There was no meningism or focal neurological deficits. Investigations revealed leukocytosis (19.1 x109/L), elevated CRP (156.8 mg/L) and sterile blood cultures. Head imaging confirmed sinusitis complicated by Pott’s puffy tumor, a small subdural empyema and sinus venous thrombosis. Ceftriaxone, metronidazole, and vancomycin were initiated with de-escalation of the latter to cloxacillin after sinus cultures grew methicillin-sensitive SA. Despite broadening to meropenem and vancomycin, he progressed to develop cerebritis. Legionella species identified from intracranial sampling using 16s RNA, allowed targeted therapy with levofloxacin and successful resolution after six weeks of therapy. Discussion The development of this patient’s Pott’s puffy tumor and intracranial complications seemed consistent with post-viral sinusitis in terms of onset and growth of SA. However, his inadequate response to broad-spectrum therapy and sterile cultures from intracranial sampling prompted request for 16sRNA testing. Subsequent disclosure of freshwater swimming exposure with aspiration event raised concerns for water-borne pathogens such as Legionella. The aspiration event occurring in presence of persisting congestion, resulted in Legionella species seeding already inflamed sinuses and further tracking intracranially. Without special cultures required to recover Legionella, this pathogen was initially missed, resulting in disease progression and delayed targeted therapy. Fluroquinolones or macrolides are required for treatment of this pathogen. Conclusion Given that post-viral sinusitis may be anticipated during viral surges, practitioners should consider the role of waterborne pathogens in hosts with significant swimming exposure who worsen on usual therapy. Microbiology and infectious diseases involvement is encouraged to optimize detection and management of waterborne infection. Practitioners are reminded that in the face of therapeutic failure, it is critical to revisit the history for unusual exposures, determine immunocompetence, and explore potential bug-drug mismatch.

Physicochemical and Microbiological Assessment of Utaewa Estuary Water

Most communities in the oil rich Niger Delta find it difficult to access to potable water due to constant pollution of their natural water sources. The sole aim of this study was to examine the microbiological and physicochemical qualities of the Estuary water at Utaewa to ascertain its suitability for potable use. Standard culture dependent techniques as well as metagenomics approach using Next Generation Sequencing (NGS) on Illumina Miseq platform was used to determine the microbiological characteristics while standard analytical procedures were employed to ascertain the physicochemical properties of Utaewa in Imo River. The average microbial counts ranged as follows: Total Heterotrophic Bacteria; 2.17±0.08x106 to 2.23±0.08x106 cfu/ml, Hydrocarbon Utilizing Bacteria; 1.03±0.06x105 to 1.39±0.08x105 cfu/ml, Total Heterotrophic Fungi; 1.23±0.13x105 to 1.64±0.09x105 cfu/ml, Hydrocarbon Utilizing Fungi; 7.9±0.21x103 to 8.6±1.00x103 cfu/ml. Bacterial isolates belonging to the genera Escherichia, Citrobacter, Bacillus, Salmonella, Shigella, Proteus, Flavobacterium, Vibrio, Micrococcus and Pseudomonas. were isolated and identified. The fungal isolates belonged to the genera Aspergillus, Rhizopus, Fusarium, Penicillium, Saccharomyces and Candida. On the other hand, Unknown (50.16%), Acinetobacter (8.34%), Ignatzschineria (4.73%), Planctomyces (3.28%), Anaerospora (3.27%), RS62 (2.73%), Methylophaga (1.64%), Wohlfahrtiimonas (1.31%), Myroides (1.23%) and Candidatus (0.95%) were captured by metagenomics analysis at the generic level. All the physicochemical parameters conformed to WHO and NIS standards for potable water except for Turbidity and Magnesium. Cultural methods used in this study were able to identify many potential water borne pathogens, metagenomics captured more microbial groups and give a better insight to bacterial composition and diversity. The presence of theses pathogenic bacteria underlies poor water quality and can pose public health threat to man and aquatic fauna. There is need to adhere to good hygienic practices and minimize the direct discharge of waste without proper treatment.

Detection and Isolation of Escherichia coli O157:H7 in Beef from Food Markets and Fecal Samples of Dairy Calves in the Peruvian Central Highlands.

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a food and waterborne pathogen with severe public health implications. We report the first-time isolation of this pathogen in the Central Highlands of Peru through standardized culture procedures and polymerase chain reaction (PCR). Escherichia coli strains were cultured from rectal-anal swabs from dairy calves and beef from food markets. The latex agglutination test was used to detect O157 and H7 antigens, and multiplex real-time PCR was carried out to detect virulence-related genes. The STEC O157:H7 strains were isolated from 3.5% (1/28) of beef samples and from 6.0% (3/50) of dairy calves that also carried both eaeA and stx1 genes. Therefore, this pathogen is a potential cause of food/waterborne disease in the region, and its surveillance in both livestock and their products should be improved to characterize the impact of its zoonotic transmission. From 2010 to 2020, E. coli was suspected in 10 outbreaks reported to the Peruvian Ministry of Health. Isolates from future outbreaks should be characterized to assess the burden posed by STEC O157:H7 in Peru.

A novel culture-enriched metagenomic sequencing strategy effectively guarantee the microbial safety of drinking water by uncovering the low abundance pathogens

Assessing the presence of waterborne pathogens and antibiotic resistance genes (ARGs) is crucial for managing the environmental quality of drinking water sources. However, detecting low abundance pathogens in such settings is challenging. In this study, a workflow was developed to enrich for broad spectrum pathogens from drinking water samples. A mock community was used to evaluate the effectiveness of various enrichment broths in detecting low-abundance pathogens. Monthly metagenomic surveillance was conducted in a drinking water source from May to September 2021, and water samples were subjected to five enrichment procedures for 6 h to recover the majority of waterborne bacterial pathogens. Oxford Nanopore Technology (ONT) was used for metagenomic sequencing of enriched samples to obtain high-quality pathogen genomes. The results showed that selective enrichment significantly increased the proportions of targeted bacterial pathogens. Compared to direct metagenomic sequencing of untreated water samples, targeted enrichment followed by ONT sequencing significantly improved the detection of waterborne pathogens and the quality of metagenome-assembled genomes (MAGs). Eighty-six high-quality MAGs, including 70 pathogen MAGs, were obtained from ONT sequencing, while only 12 MAGs representing 10 species were obtained from direct metagenomic sequencing of untreated water samples. In addition, ONT sequencing improved the recovery of mobile genetic elements and the accuracy of phylogenetic analysis. This study highlights the urgent need for efficient methodologies to detect and manage microbial risks in drinking water sources. The developed workflow provides a cost-effective approach for environmental management of drinking water sources with microbial risks. The study also uncovered pathogens that were not detected by traditional methods, thereby advancing microbial risk management of drinking water sources.

A 3D printed microfluidic device for scalable multiplexed CRISPR-cas12a biosensing.

Accurate, rapid, and multiplexed nucleic acid detection is critical for environmental and biomedical monitoring. In recent years, CRISPR-Cas12a has shown great potential in improving the performance of DNA biosensing. However, the nonspecific trans-cleavage activity of Cas12a complicates the multiplexing capability of Cas12a biosensing. We report a 3D-printed composable microfluidic plate (cPlate) device that utilizes miniaturized wells and microfluidic loading for a multiplexed CRISPR-Cas12a assay. The device easily combines loop-mediated isothermal amplification (LAMP) and CRISPR-Cas12a readout in a simple and high-throughput workflow with low reagent consumption. To ensure the maximum performance of the device, the concentration of Cas12a and detection probe was optimized, which yielded a four-fold sensitivity improvement. Our device demonstrates sensitive detection to the fg mL- 1 level for four waterborne pathogens including shigella, campylobacter, cholera, and legionella within 1h, making it suitable for low-resource settings.

Fate of Cryptosporidium and Giardia through conventional and compact drinking water treatment plants

Over the past three decades, a notable rise in the occurrence of enteric protozoan pathogens, especially Giardia and Cryptosporidium spp., in drinking water sources has been observed. This rise could be attributed not only to an actual increase in water contamination but also to improvements in detection methods. These waterborne pathogens have played a pivotal role in disease outbreaks and the overall escalation of disease rates in both developed and developing nations worldwide. Consequently, the control of waterborne diseases has become a vital component of public health policies and a primary objective of drinking water treatment plants (DWTPs). Limited studies applied real-time PCR (qPCR) and/or immunofluorescence assay (IFA) for monitoring Giardia and Cryptosporidium spp., particularly in developing countries like Egypt. Water samples from two conventional drinking water treatment plants and two compact units (CUs) were analyzed using both IFA and qPCR methods to detect Giardia and Cryptosporidium. Using qPCR and IFA, the conventional DWTPs showed complete removal of Giardia and Cryptosporidium, whereas Mansheyat Alqanater and Niklah CUs achieved only partial removal. Specifically, Cryptosporidium gene copies removal rates were 33.33% and 60% for Mansheyat Alqanater and Niklah CUs, respectively. Niklah CU also removed 50% of Giardia gene copies, but no Giardia gene copies were removed by Mansheyat Alqanater CU. Using IFA, both Mansheyat Alqanater and Niklah CUs showed a similar removal rate of 50% for Giardia cysts. Additionally, Niklah CU achieved a 50% removal of Cryptosporidium oocysts, whereas Mansheyat Alqanater CU did not show any removal of Cryptosporidium oocysts. Conventional DWTPs were more effective than CUs in removing enteric protozoa. The contamination of drinking water by enteric pathogenic protozoa remains a significant issue globally, leading to increased disease rates. Infectious disease surveillance in drinking water is an important epidemiological tool to monitor the health of a population.

Control of water-borne diseases via awareness and vaccination using multilayer networks

Communicable diseases are one of the challenges to people’s health and fitness. Consuming contaminated water or food and inhaling contaminated water droplets are the main causes of water-borne pathogens spread. This paper studies the spreading dynamics of water-borne diseases with vaccination and preventive measures over a multilayer network. SVIR-process for disease spread over humans and SIS-process for disease spread over water supply mediums and UAU-process for awareness diffusion over humans via social media are taken to study the spreading dynamics. The Discrete-time Markov chain approach is used to frame and analyse the model. The optimal value corresponding to the vaccination parameter is found to control the disease spread. The impact of awareness and vaccination over disease spread and the characteristics of basic reproduction number are found via numerical simulation.

The potential risks of Legionella arising from ligature-resistant fixtures

To provide a safe environment, behavioral health settings must adhere to "ligature-resistant" protocols for patients at risk of harm to themselves or others. However, certain bathroom ligature-resistant fixtures alter environmental controls, such as sinks and showerheads, and increase the risk of water-borne pathogens due to low water output settings, highlighting the importance of an interdisciplinary water management program. We describe how ligature-resistant water fixtures may have been associated with a possible case of hospital-associated Legionellosis.

Waterborne viruses in urban groundwater environments

The proportion of global population using urban aquifers as drinking water sources increases every year and indeed the groundwater quality is not monitored adequately. Although norovirus has been identified as the first cause of groundwater-related outbreaks, the surveillance of waterborne viruses has been rather neglected. From ageing or disrupted sewer systems, occasional sewer discharges (e.g. combined sewer overflows, storm runoff), to poorly managed reclaimed water infiltration practices, multiple are the pathways that cause groundwater quality deterioration. This study revises the main viral contamination sources and the factors affecting viral contamination of groundwater bodies in terms of transport, inactivation, and survival of the viral particles. It also summarizes the methods used for those reporting the presence of human viruses in urban groundwaters. A total of 36 articles have been included in the method survey spanning a period of 24 years (1999–2022). There is a need of systematic monitoring considering representative set of waterborne pathogens. The evaluation of the presence of human adenovirus seems a useful tool to predict the presence of other waterborne pathogens in groundwater. Large volume sampling methods, but also new passive sampling methodologies applied to groundwater, coupled to target massive sequencing approaches may elucidate the range of pathogens capable of contaminating urban groundwaters for further evaluation of risk.

Differences in pathogenic community assembly processes and their interactions with bacterial communities in river and lake ecosystems

Pathogenic bacterial infections caused by water quality degradation are one of the most widespread environmental problems. Clarifying the structure of pathogens and their assembly mechanisms in lake ecosystems is vital to prevent the infestation of waterborne pathogens and maintain human health. However, the composition and assembly mechanisms of pathogenic bacterial communities in river and lake ecosystems are still poorly understood. In this study, we collected 17 water and 17 sediment samples from Lake Chaohu and its 11 inflow rivers. Sequencing of 16S rRNA genes was used to study bacterial pathogen communities. The results of the study showed that there was a significant difference (P < 0.05) in the composition of the pathogen community between riverine and lake habitats. Acinetobacter (36.49%) was the dominant bacterium in the river, whereas Flavobacterium (21.6%) was the most abundant bacterium in the lake. Deterministic processes (i.e., environmental filtering and species interaction) drove the assembly of pathogenic bacterial communities in the lake habitat, while stochastic processes shaped river pathogenic bacterial communities. Spearman correlation analysis showed that the α-diversity of bacterial communities was linearly and negatively linked to the relative abundance of pathogens. Having a higher bacterial community diversity had a suppressive effect on pathogen abundance. In addition, co-occurrence network analysis showed that bacterial communities were tightly linked to pathogenic bacteria. Pseudomonas aeruginosa and Salmonella enterica were identified as keystone species in an inflow water sampling network (W_FR), reducing the complexity of the network. These results provide a reference for assessments of water quality safety and pathogenic bacteria posing risks to human health in large freshwater lakes.

Material-engineered bioartificial microorganisms enabling efficient scavenging of waterborne viruses

Material-based tactics have attracted extensive attention in driving the functional evolution of organisms. In aiming to design steerable bioartificial organisms to scavenge pathogenic waterborne viruses, we engineer Paramecium caudatum (Para), single-celled microorganisms, with a semiartificial and specific virus-scavenging organelle (VSO). Fe3O4 magnetic nanoparticles modified with a virus-capture antibody (MNPs@Ab) are integrated into the vacuoles of Para during feeding to produce VSOs, which persist inside Para without impairing their swimming ability. Compared with natural Para, which has no capture specificity and shows inefficient inactivation, the VSO-engineered Para (E-Para) specifically gathers waterborne viruses and confines them inside the VSOs, where the captured viruses are completely deactivated because the peroxidase-like nano-Fe3O4 produces virus-killing hydroxyl radicals (•OH) within acidic environment of VSO. After treatment, magnetized E-Para is readily recycled and reused, avoiding further contamination. Materials-based artificial organelles convert natural Para into a living virus scavenger, facilitating waterborne virus clearance without extra energy consumption.

Engineered multi-walled carbon nanotubes for disinfecting wastewater

Discharging a considerable amount of untreated effluent directly into a water body significantly impacts water quality. Contaminated water can spread waterborne infections, resulting in exponentially high death rates worldwide. Although carbon nanotubes are frequently employed in industry, little is understood about how they may affect aquatic microbial ecosystems. Therefore, the present investigation aimed to exploit multi-walled carbon nanotubes (MWCNTs) as a potential disinfectant to eliminate waterborne bacteria during wastewater treatment. The current study utilized six different microbial strains, including Escherichia coli O157, Salmonella enterica, Staphylococcus aureus, Enterococcus faecalis, Risopus oryzae, and Rhizomucor miehei, to examine the antimicrobial properties of MWCNTs. The physical and morphological properties of MWCNTs were characterized using transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), and zeta potential. The FTIR spectra of MWCNTs have appeared at 11,029 cm−1, and the zeta potential and particle size recorded at −28.89 mV and 425 nm, respectively. On the other hand, the results indicated that the width of the inhibition zone varied between 11 and 29 mm for E. coli O157, 11–31 mm for S. enterica, 16–37 mm for S. aureus, 14–34 mm for E.faecalis, 10–26 mm for R. oryzae, and 10–24 mm for Rh. miehei. The reduction rate of disinfection was estimated. The effective dose of MWCNTs (4xMIC) in a disinfection experiment could all selectedpathogens after 125 min exposure time. This study provided an overview of the antimicrobial properties of MWCNTs, their multiple modes of action against pathogens, and their usefulness in wastewater disinfection and microbial control. Thus, this current research work can also recommend MWCNTs as a good solution and beneficial disinfecting agent for inactivating waterborne pathogens within wastewater handling.

Oriented porous hydrogel with excellent anti-salt and antibacterial properties for high-performance interfacial solar steam generation

In recent years, solar interfacial evaporation has drawn substantial attention in wastewater and seawater treatment, but it still requires intensive development in high-performance evaporators, particularly simultaneous with high anti-salt and antibacterial abilities to supply freshwater. In this work, a directionally channeled evaporator with excellent resistance to salt crystallization and microbial was designed and synthesized by using silver nanoparticles (AgNPs) / polydopamine (PDA) hydrogel via a simple freeze-dried method. The novel structure was proposed to enhance convection and accelerate water transport that prevents salt crystallization. PDA and AgNPs were deposited to achieve superb optical absorption, photothermal conversion and anti-biofouling ability. Therefore, the evaporation rate of the AgNPs-PDA hydrogel achieved 1.70 kg m−2 h−1 with a light-to-heat conversion efficiency of 90.3 %. Based on the efficient evaporation ability and especially structure of the AgNPs-PDA hydrogel, the evaporator presented a tolerance to high salt water and the stable evaporation performance of actual seawater evaporation during long-time application. Simultaneously, the addition of AgNPs endowed the AgNPs-PDA hydrogel evaporator with excellent antibacterial ability. Thus, these favorable properties endowed the special AgNPs-PDA hydrogel evaporator a great potential for obtaining efficient evaporation and simultaneously solving the fouling problem, especially to waterborne pathogens and salt crystallization in tanglesome applications.

A method of recovering the very low concentration of pathogens in river water by combining centrifugation and membrane filtration

Waterborne pathogens present major public health concerns because of the associated high mortality, morbidity and cost of treatment. Consumption of and contact with water contaminated by faeces is a significant risk factor for transmitting these organisms to humans. Their detection in a water sample is critical to ascertain potential risks to humans. They are relatively low in concentrations in surface waters, making their detection a challenge. Campylobacter is targeted here because it is one of the leading causes of enteric diseases globally, and consensus on the superiority of centrifugation over filtration, and vice versa, to recover Campylobacter spp. from river water samples for detection, has yet to be. Therefore, for this study river water sample was processed by combining both methods in a single set-up to concentrate Campylobacter spp. cells from water samples. This method of combining centrifugation and filtration can be expanded to other bacterial waterborne pathogens of public health importance.•Concentrating cells by centrifugation (14,000 × g for 30 min) to collect the pellets, followed by membrane filtration (using 0.45 µm) of the supernatant to trap any remaining suspended cells, and then pooling both pellet and residue presents an effective method for obtaining a satisfactory quantitative recovery of waterborne pathogens, such as Campylobacter spp. from environmental waters.•This is a critical need for quantitative microbial risk assessment studies.

Nanotherapeutic delivery of antibiotic cocktail enhances intra-macrophage killing of Mycobacterium marinum

Mycobacterium marinum is a waterborne pathogen responsible for tuberculosis-like infections in cold-blooded animals and is an opportunistic pathogen in humans. M. marinum is the closest genetic relative of the Mycobacterium tuberculosis complex and is a reliable surrogate for drug susceptibility testing. We synthesized and evaluated two nanoparticle (NP) formulations for compatibility with rifampicin, isoniazid, pyrazinamide, and ethambutol (PIRE), the front-line antimycobacterial drugs used in combination against active tuberculosis infections. Improved in vitro antimicrobial activity was observed with encapsulated rifampicin alone or in a cocktail of drugs formulated through co-encapsulation in amphiphilic polyanhydride NPs. Broth antimicrobial testing revealed that the encapsulation of PIRE in NP resulted in a significant increase in antimicrobial activity, with the benefit over soluble formulations at biologically relevant concentrations ranging from &amp;gt;10 to &amp;gt;3,000 fold. M. marinum-infected human macrophages treated with NP-PIRE were cleared of viable bacteria in 48 h following a single treatment, representing a &amp;gt;4 log reduction in colony-forming units and a &amp;gt;2,000-fold increase in antimicrobial activity. The amphiphilic polyanhydride nanoparticles demonstrated the ability to co-encapsulate PIRE antibiotics and enhance their antimicrobial activity against M. marinum in infected macrophages in culture and in vitro. These data suggest that polyanhydride nanoparticles are a promising nanotherapeutic for combatting Mycobacterium infections through improved intracellular targeting of encapsulated antibiotics.

Traveling waves of a discrete diffusive waterborne pathogen model with general incidence

We study traveling waves of a discrete diffusive waterborne pathogen model with general incidence. The existence and non-existence of traveling waves depend on the basic reproduction number R0 and minimum wave speed c∗. When R0>1 and c≥c∗, applying the Schauder fixed point theorem, technique of Lyapunov function and the limiting argument, we establish the traveling waves connecting the disease-free equilibrium and endemic equilibrium. If R0≤1 or R0>1 and c<c∗, the non-existence of traveling waves can be verified by using the comparison principle and the method of Laplace transform. From our result one can see the diffusion rates of infectious individuals and bacteria in water can increase the minimum wave speed.