Sarah Lowry

Bio: Sarah Lowry is an academic researcher from Georgia Institute of Technology. The author has contributed to research in topics: Airborne transmission & Viral shedding. The author has an hindex of 2, co-authored 5 publications receiving 19 citations.

Detection and Quantification of Enteric Pathogens in Aerosols Near Open Wastewater Canals in Cities with Poor Sanitation.

Abstract: Urban sanitation infrastructure is inadequate in many low-income countries, leading to the presence of highly concentrated, uncontained fecal waste streams in densely populated areas. Combined with mechanisms of aerosolization, airborne transport of enteric microbes and their genetic material is possible in such settings but remains poorly characterized. We detected and quantified enteric pathogen-associated gene targets in aerosol samples near open wastewater canals (OWCs) or impacted (receiving sewage or wastewater) surface waters and control sites in La Paz, Bolivia; Kanpur, India; and Atlanta, USA, via multiplex reverse-transcription qPCR (37 targets) and ddPCR (13 targets). We detected a wide range of enteric targets, some not previously reported in extramural urban aerosols, with more frequent detections of all enteric targets at higher densities in La Paz and Kanpur near OWCs. We report density estimates ranging up to 4.7 × 102 gc per mair3 across all targets including heat-stable enterotoxigenic Escherichia coli, Campylobacter jejuni, enteroinvasive E. coli/Shigella spp., Salmonella spp., norovirus, and Cryptosporidium spp. Estimated 25, 76, and 0% of samples containing positive pathogen detects were accompanied by culturable E. coli in La Paz, Kanpur, and Atlanta, respectively, suggesting potential for viability of enteric microbes at the point of sampling. Airborne transmission of enteric pathogens merits further investigation in cities with poor sanitation.

Waterborne pathogen monitoring in Jaipur, India reveals potential microbial risks of urban groundwater supply

Abstract: The Sustainable Development Goals require that 100 mL water samples contain no culturable E. coli to classify a water supply as “safely managed” from a microbial perspective. But small volume sampling is often insufficient for detecting microbial risks. We used culture-based measures of total coliforms and E. coli along with dead-end ultrafiltration (DEUF) and droplet digital PCR (ddPCR) to assess the microbial water quality of an urban water supply in Jaipur, India. Despite the absence of culturable E. coli in 90% of the 100 mL grab samples (n = 20) during the 10-day sampling period, we detected genes associated with protozoan and bacterial pathogens (Giardia, Cryptosporidium, and enterotoxigenic E. coli) in 3 DEUF samples of groundwater (n = 9; volume 59 to 122.4 liters). Of the three groundwater samples positive for waterborne pathogens, two were associated with 100 mL grab samples that were negative for culturable E. coli. Methods with improved analytical sensitivity, such as DEUF and ddPCR, can detect evidence of pathogens in drinking water supplies and supplement conventional culture-based methods to better inform pathogen-specific risk assessment and management.

Detection and quantification of enteric pathogens in aerosols near uncontained fecal waste streams in cities with poor sanitation

Abstract: Urban sanitation infrastructure is inadequate in many low-income countries, leading to the presence of highly concentrated, uncontained fecal waste streams in densely populated areas. Combined with mechanisms of aerosolization, airborne transport of enteric microbes and their genetic material is possible in such settings but remains poorly characterized. We detected and quantified enteric pathogen-associated gene targets in aerosol samples near open wastewater canals (OWCs) or impacted surface waters and control sites in La Paz, Bolivia; Kanpur, India; and Atlanta, USA via multiplex qPCR (37 targets) and ddPCR (13 targets). We detected a wide range enteric pathogen-specific targets, some not previously reported in extramural urban aerosols, with more frequent detections of all enteric targets at higher densities in La Paz and Kanpur near OWCs. We report density estimates ranging from non-detects to 4.7 [x] 102 gc per m3air for targets including ST-ETEC, C. jejuni, EIEC/Shigella spp., Salmonella spp., adenovirus, and Cryptosporidium spp. An estimated 25%, 76%, and 0% of samples containing positive pathogen detects were accompanied by culturable E. coli in La Paz, Kanpur, and Atlanta, respectively, suggesting potential for viability of enteric microbes at the point of sampling. Airborne transmission of enteric pathogens merits further investigation in cities with poor sanitation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/21251650v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@13c817borg.highwire.dtl.DTLVardef@158e108org.highwire.dtl.DTLVardef@1e0626org.highwire.dtl.DTLVardef@125b214_HPS_FORMAT_FIGEXP M_FIG C_FIG SYNOPSISWe detect and quantify molecular targets associated with important enteric pathogens in outdoor aerosols from cities with poor sanitation to assess the potential role of the aeromicrobiological pathway in enteric infection transmission in such settings.

Within- and between-Day Variability of SARS-CoV-2 RNA in Municipal Wastewater during Periods of Varying COVID-19 Prevalence and Positivity

Abstract: Wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA is being used to monitor Coronavirus Disease 2019 (COVID-19) trends in communities;however, within- and between-day variation of SARS-CoV-2 RNA concentration in primary influent remains largely uncharacterized. In the current study, grab sampling of primary influent was performed every 2 h over two 24-h periods at two wastewater treatment plants (WWTPs) in northern Indiana, USA. The recovery efficiency of endogenous SARS-CoV-2 RNA in wastewater was confirmed to be similar to the recovery efficiency of the process control, bovine respiratory syncytial virus (BRSV). Recovery-corrected SARS-CoV-2 RNA concentrations in primary influent indicate diurnal loading patterns and confirm monitoring dependent on grab samples should target daytime periods with high fecal loading. Importantly, manual compositing performed at the WWTP resulted in concentrations that were consistently lower than grab sample averages indicating potential bias. Uncorrected, recovery-corrected, and pepper mild mottle virus (PMMoV)-normalized SARS-CoV-2 RNA concentrations demonstrated an ordinal agreement with increasing clinical COVID-19 positivity but not COVID-19 cases. In areas where geolocated COVID-19 case data are not available, the COVID-19 positivity rate could provide a useful county-level metric for comparison with wastewater. Nonetheless, large variation both within- and between-days may preclude robust quantitative analyses beyond correlation.