Water Resources Research Act Program

Details for Project ID 2018KY275B

Assessment of MRSA presence in suburban WWTPs effluent in Lexington, Kentucky

Institute: Kentucky
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $10,000 Total Non-Federal Funds: $20,100

Principal Investigators: Gail Brion, Atena Amirsoleimani

Project Summary: Antibiotic resistant bacteria are winning the war against humanity, adapting faster than we can create new antibiotics, spreading farther, persisting longer in the environment, and becoming an expensive source of endemic disease in the USA, and worldwide. Engineers may have unwittingly encouraged the adaptation of pathogenic bacteria through extended contact with rich sludge microbiomes that contain multiple antimicrobial resistance genes, mobile genetic elements, and bacteriophage vectors required for transport between bacteria. Staphylococcus aureus (SA) has adapted to selective environmental pressures by acquiring extra genes that have increased its virulence, conferred resistance to a wide range of antimicrobials, and allowed SA to expand beyond its normal niche in the nose and throat of animals, into our rivers, beaches, and oceans. SA passage through WWTPs is thought to have resulted in divergent stains of hardier and more virulent pathogens, such as community-acquired, Methicillin-Resistant SA (CA-MRSA), which have supplanted hospital-acquired Methicillin-Resistant SA (HA-MRSA) to become the dominant cause of reported SA infections in the USA. Environmental persistence of SA has been documented in multiple media, as well as a consistent presence of SA in wastewater influents and sludges. However, the presence of MRSA may be overstated due to problems with co-culture of S. epidermidis (SE), a closely related organisms that shares the antibiotic resistant protein of MRSA, causing a number of false positives with current clinical methods for culture of SA. We have developed new media that suppresses the growth of SE, and allows for the selective growth of SA from messy environmental samples. The overall objective of the proposed plan of research is to investigate the presence, fate, and potential transport into watershed sediments of Methicillin Resistant Staphylococcus aureus (MRSA) bacteria in treated sewage effluent and receiving stream sediments employing our newly developed, SE suppressive, SA enrichment and isolation method, followed by culture typing of clones for penicillin binding protein and coagulase to determine which are MRSA. The MRSA isolates will have their genetic material harvested in preparation for whole genome sequencing for typing and virulence factors. This project seeks to provide insight into the prevalence of SA and MRSA, and genomic content of MRSA, in the effluent from two, activated-sludge-based, wastewater treatment plants by collecting large volume samples at the effluent and in the river sediment collecting in pools downstream of the effluent, enriching SA in selective culture, isolating and identifying viable, clean MRSA clones, extracting the genetic material from the isolate clones, and sequencing a few of their genomes for typing and virulence gene comparison. It is expected that we will isolate MRSA from sewage effluent, and the sediments below the effluent. What remains to be seen is if these isolates prove to have adaptations that allow them to persist and spread further through our watershed environments.