More Like this

1. Detection of Salmonella enterica and Listeria monocytogenes in alternative irrigation water by culture and qPCR-based methods in the Mid-Atlantic U.S.

   https://doi.org/10.1128/spectrum.03536-23  

   Acheamfour, Chanelle L; Parveen, Salina; Gutierrez, Alan; Handy, Eric T; Behal, Sara; Kim, Donghyun; Kim, Seongyun; East, Cheryl; Xiong, Ray; Haymaker, Joseph R; et al (April 2024, Microbiology Spectrum)

   Wang, Luxin (Ed.)

   ABSTRACT Alternative irrigation waters (rivers, ponds, and reclaimed water) can harbor bacterial foodborne pathogens likeSalmonella entericaandListeria monocytogenes, potentially contaminating fruit and vegetable commodities. Detecting foodborne pathogens using qPCR-based methods may accelerate testing methods and procedures compared to culture-based methods. This study compared detectionof S. enterica and L. monocytogenesby qPCR (real-time PCR) and culture methods in irrigation waters to determine the influence of water type (river, pond, and reclaimed water), season (winter, spring, summer, and fall), or volume (0.1, 1, and 10 L) on sensitivity, accuracy, specificity, and positive (PPV), and negative (NPV) predictive values of these methods. Water samples were collected by filtration through modified Moore swabs (MMS) over a 2-year period at 11 sites in the Mid-Atlantic U.S. on a bi-weekly or monthly schedule. For qPCR, bacterial DNA from culture-enriched samples (n= 1,990) was analyzed by multiplex qPCR specific forS. entericaandL. monocytogenes. For culture detection, enriched samples were selectively enriched, isolated, and PCR confirmed. PPVs for qPCR detection ofS. entericaandL. monocytogeneswere 68% and 67%, respectively. The NPV were 87% (S. enterica) and 85% (L. monocytogenes). Higher levels of qPCR/culture agreement were observed in spring and summer compared to fall and winter forS. enterica; forL. monocytogenes, lower levels of agreement were observed in winter compared to spring, summer, and fall. Reclaimed and pond water supported higher levels of qPCR/culture agreement compared to river water for bothS. entericaandL. monocytogenes, indicating that water type may influence the agreement of these results. IMPORTANCEDetecting foodborne pathogens in irrigation water can inform interventions and management strategies to reduce risk of contamination and illness associated with fresh and fresh-cut fruits and vegetables. The use of non-culture methods like qPCR has the potential to accelerate the testing process. Results indicated that pond and reclaimed water showed higher levels of agreement between culture and qPCR methods than river water, perhaps due to specific physiochemical characteristics of the water. These findings also show that season and sample volume affect the agreement of qPCR and culture results. Overall, qPCR methods could be more confidently utilized to determine the absence ofSalmonella entericaandListeria monocytogenesin irrigation water samples examined in this study. 

   more » « less
2. Extended Spectrum β-Lactamase Activity and Cephalosporin Resistance in Escherichia coli from U.S. Mid-Atlantic Surface and Reclaimed Water

   https://doi.org/10.1128/aem.00837-22  

   Solaiman, Sultana; Handy, Eric; Brinks, Taylor; Goon, Kasey; Bollinger, Chris; Sapkota, Amy R.; Sharma, Manan; Micallef, Shirley A. (August 2022, Applied and Environmental Microbiology)

   Villanueva, Laura (Ed.)

   ABSTRACT Phylogenetic distribution and extended spectrum β-lactamase (ESBL) activity of Escherichia coli recovered from surface and reclaimed water in the mid-Atlantic U.S. were evaluated. Among 488 isolates, phylogroups B1 and A were the most and least prevalent, respectively. Water type, but not season, affected phylogroup distribution. The likelihood of detecting group A isolates was higher in reclaimed than pond ( P <  0.01), freshwater river ( P <  0.01) or brackish river (P <  0.05) water. Homogeneity in group distribution was lowest in pond water, where group B1 comprised 50% of isolates. Only 16 (3.3%) isolates exhibited phenotypic resistance to one or more cephalosporins tested and only four had ESBL activity, representing groups B1, B2 isolates, and D. Phylogroup was a factor in antimicrobial resistance ( P <  0.05), with group A (8.7%) and D (1.6%) exhibiting the highest and lowest rates. Resistance to cefoxitin was the most prevalent. Multi- versus single drug resistance was affected by phylogroup ( P <  0.05) and more likely in groups D and B1 than A which carried resistance to cefoxitin only. The most detected β-lactam resistance genes were bla CMY-2 and bla TEM . Water type was a factor for bla CTX-M gene detection ( P <  0.05). Phenotypic resistance to cefotaxime, ceftriaxone, cefuroxime and ceftazidime, and genetic determinants for ESBL-mediated resistance were found predominantly in B2 and D isolates from rivers and reclaimed water. Overall, ESBL activity and cephalosporin resistance in reclaimed and surface water isolates were low. Integrating data on ESBL activity and β-lactam resistance among E. coli populations can inform decisions on safety of irrigation water sources and One Health. IMPORTANCE Extended spectrum β-lactamase (ESBL) producing bacteria, that are resistant to a broad range of antimicrobial agents, are spreading in the environment but data remain scarce. ESBL-producing Escherichia coli infections in the community are on the rise. This work was conducted to assess presence of ESBL-producing E. coli in water that could be used for irrigation of fresh produce. The study provides the most extensive evaluation of ESBL-producing E. coli in surface and reclaimed water in the mid-Atlantic United States. The prevalence of ESBL producers was low and phenotypic resistance to cephalosporins (types of β-lactam antibiotics) was affected by season but not water type. Data on antimicrobial resistance among E. coli populations in water can inform decisions on safety of irrigation water sources and One Health. 

   more » « less
3. Investigating water safety in multi-purpose buildings used as an elementary school and plumbing remediation effectiveness

   https://doi.org/10.1371/journal.pwat.0000141  

   Ra, Kyungyeon; Proctor, Caitlin; Ley, Christian; Angert, Danielle; Noh, Yoorae; Isaacson, Kristofer; Shah, Amisha; Whelton, Andrew J. (July 2023, PLOS Water)

   Herrera, Manuel (Ed.)

   Three buildings that were repurposed for use as an elementary school were shutdown for three months in response to the pandemic. Building cold and hot water quality was monitored before reopening to detect and resolve chemical and microbiological problems. The authors collected first draw pre-flush and post-flush water samples. First draw water samples did not contain detectable disinfectant residual, but nickel and lead sometimes exceeded the health-based action limits for cold water (max. 144 μg Ni/L, 3.4 μg Pb/L). Stagnant cold water at a bathroom sink (188 MPN/100 mL) and drinking water fountain (141.6 MPN/100 mL), in the same building, exceeded the L . pneumophila thresholds advised by the World Health Organization (WHO) (10 CFU/mL) and American Industrial Hygiene Association (AIHA) (100 CFU/mL). Fixture flushing was conducted to remove cold and hot stagnant water and no L . pneumophila was detected immediately after flushing. Two weeks after no subsequent building water use, chemical and microbiological contaminant levels were found to be similar to levels prior to flushing with one exception. The maximum L . pneumophila level (kitchen sink, hot water: 61.1 MPN/100 mL) was found in a different building than the prior maximum detections. No repeat positive locations for L . pneumophila were found during the second visit, but new fixtures were positive the organism. When this study was conducted no evidence-based guidelines for plumbing recommissioning were available. A single plumbing flush reduced heavy metal and L . pneumophila levels below WHO and AIHA thresholds in all three buildings. Additional work is needed to examine the role of building size, type and plumbing design on fixture water quality in shutdown buildings. 

   more » « less
4. Developing a Multicriteria Decision Analysis Framework to Evaluate Reclaimed Wastewater Use for Agricultural Irrigation: The Case Study of Maryland

   https://doi.org/10.3390/hydrology8010004  

   Paul, Manashi; Negahban-Azar, Masoud; Shirmohammadi, Adel; Montas, Hubert (March 2021, Hydrology)

   null (Ed.)

   Groundwater is the main source of irrigation and residential use in the Eastern Shore Maryland, which is experiencing challenges regarding overuse, saltwater intrusion, and diminishing productivity. The Chesapeake Bay is also facing the problem of water pollution due to pollutant loading from agricultural fields and wastewater treatment plants (WWTPs). Using recycled water for irrigation has the potential to alleviate the pressure on groundwater and reduce pollutant loading. The objective of this study was to develop a decision tool to explore the use of recycled water for agricultural irrigation in Maryland using Multicriteria Decision Analysis (MCDA) integrated with Geographical Information Systems (GIS). Four main evaluation criteria were included in the GIS-MCDA framework: agricultural land cover, climate, groundwater vulnerability, and characteristics of the WWTPs as sources of recycled water. Groundwater vulnerability zones were developed using the groundwater well density, water extraction data, and the aquifer information. Then, the most suitable areas for irrigation using recycled water were identified. About 13.5% and 32.9% of agricultural land was, respectively, found to be “highly” and “moderately” suitable for irrigation with recycled water when WWTPs were categorized based on their treatment process information. The results provide a useful decision tool to promote the use of recycled water for agricultural irrigation. 

   more » « less
5. Photoactivated Carbon Dots for Inactivation of Foodborne Pathogens Listeria and Salmonella

   https://doi.org/10.1128/AEM.01042-21  

   Dong, Xiuli; Wang, Ping; Darby, Jasmine P.; Tang, Yongan; Overton, Christopher M.; Kathariou, Sophia; Sun, Ya-Ping; Yang, Liju (November 2021, Applied and Environmental Microbiology)

   Björkroth, Johanna (Ed.)

   ABSTRACT Foodborne pathogens have long been recognized as major challenges for the food industry and repeatedly implicated in food product recalls and outbreaks of foodborne diseases. This study demonstrated the application of a recently discovered class of visible-light-activated carbon-based nanoparticles, namely, carbon dots (CDots), for photodynamic inactivation of foodborne pathogens. The results demonstrated that CDots were highly effective in the photoinactivation of Listeria monocytogenes in suspensions and on stainless steel surfaces. However, it was much less effective for Salmonella cells, but treatments with higher CDot concentrations and longer times were still able to inactivate Salmonella cells. The mechanistic implications of the observed different antibacterial effects on the two types of cells were assessed, and the associated generation of intracellular reactive oxygen species (ROS), the resulting lipid peroxidation, and the leakage of nucleic acid and proteins from the treated cells were analyzed, with the results collectively suggesting CDots as a class of promising photodynamic inactivation agents for foodborne pathogens. IMPORTANCE Foodborne infectious diseases have long been recognized as major challenges in public health. Contaminations of food processing facilities and equipment with foodborne pathogens occur often. There is a critical need for new tools/approaches to control the pathogens and prevent such contaminations in food processing facilities and other settings. This study reports a newly established antimicrobial nanomaterials platform, CDots coupled with visible/natural light, for effective and efficient inactivation of representative foodborne bacterial pathogens. The study will contribute to promoting the practical application of CDots as a new class of promising nanomaterial-based photodynamic inactivation agents for foodborne pathogens. 

   more » « less