Relating Antimicrobial Resistance and Virulence in Surface-Water E. coli.

The role of the environment in the emergence and spread of antimicrobial resistance (AMR) is being increasingly recognized, raising questions about the public health risks associated with environmental AMR. Yet, little is known about pathogenicity among resistant bacteria in environmental systems. Existing studies on the association between AMR and virulence are contradictory, as fitness costs and genetic co-occurrence can be opposing influences. Using Escherichia coli isolated from surface waters in eastern North Carolina, we compared virulence gene prevalence between isolates resistant and susceptible to antibiotics. We also compared the prevalence of isolates from sub-watersheds with or without commercial hog operations (CHOs). Isolates that had previously been evaluated for phenotypic AMR were paired by matching isolates resistant to any tested antibiotic with fully susceptible isolates from the same sample date and site, forming 87 pairs. These 174 isolates were evaluated by conventional PCR for seven virulence genes (bfp, fimH, cnf-1, STa (estA), EAST-1 (astA), eae, and hlyA). One gene, fimH, was found in 93.1% of isolates. Excluding fimH, at least one virulence gene was detected in 24.7% of isolates. Significant negative associations were found between resistance to at least one antibiotic and presence of at least one virulence gene, tetracycline resistance and presence of a virulence gene, resistance and STa presence, and tetracycline resistance and STa presence. No significant associations were found between CHO presence and virulence, though some sub-significant associations merit further study. This work builds our understanding of factors controlling AMR dissemination through the environment and potential health risks.

Evidence Map and Systematic Review of Disinfection Efficacy on Environmental Surfaces in Healthcare Facilities.

Healthcare-associated infections (HAIs) contribute to patient morbidity and mortality with an estimated 1.7 million infections and 99,000 deaths costing USD $28-34 billion annually in the United States alone. There is little understanding as to if current environmental surface disinfection practices reduce pathogen load, and subsequently HAIs, in critical care settings. This evidence map includes a systematic review on the efficacy of disinfecting environmental surfaces in healthcare facilities. We screened 17,064 abstracts, 635 full texts, and included 181 articles for data extraction and study quality assessment. We reviewed ten disinfectant types and compared disinfectants with respect to study design, outcome organism, and fourteen indictors of study quality. We found important areas for improvement and gaps in the research related to study design, implementation, and analysis. Implementation of disinfection, a determinant of disinfection outcomes, was not measured in most studies and few studies assessed fungi or viruses. Assessing and comparing disinfection efficacy was impeded by study heterogeneity; however, we catalogued the outcomes and results for each disinfection type. We concluded that guidelines for disinfectant use are primarily based on laboratory data rather than a systematic review of in situ disinfection efficacy. It is critically important for practitioners and researchers to consider system-level efficacy and not just the efficacy of the disinfectant.

Integrating remote sensing with nutrient management plans to calculate nitrogen parameters for swine CAFOs at the sprayfield and sub-watershed scales.

North Carolina (NC) regulates swine concentrated animal feeding operations (CAFOs) using five-year nutrient management plans (NMPs) requiring the plant available nitrogen sprayed (PANspray) to be less than that utilized by crops (PANcrops), i.e. the PAN balance (defined as PANbal=PANspray-PANcrops) remains negative, which avoids over-spraying liquid effluent onto crops. Objectives of this research are first to characterize Duplin County sprayfields and PANbal by creating the first, open-source sprayfield spatial database created for swine CAFOs in NC (for Duplin County). Second, this paper finds that for two sub-watershed scales 199 additional catchments and 1 additional HUC12 were identified as having permitted lagoon effluent applied compared to using CAFO point locations for a total of 510 catchments and 34 HUC12s with swine CAFO sprayfields. Third, a new method disaggregates annual PANbal from NMPs using remote sensing crop data. And finally, probability that sprayfields have excess PANbal is estimated due to k, a PAN availability coefficient. The remote sensing approach finds that 9-14% of catchments in a given year and 24% of catchments over a five year period have a positive PANbal. An additional 3-4% of catchments have probability of a positive PANbal due to variability in k. This work quantifies the impact of crop rotations on of sprayfields at the catchment spatial scale with respect to PANbal and highlights some of the limitations of NMPs have for estimation of PANbal. We recommend that NMPs be permitted based on the crop rotation scenario utilizing the least PAN and that swine producer compliance to manure management practice be encouraged.