Identification of Biological Contaminants Isolated From Waste Water Treatment Process
Board Location: #7
Discipline: Biological Sciences
Subcategory: biochemistry
Session: 1
Cassandra Naomi Palacios - Arizona State University
Co-Author(s): Hannah Harvey, Phoenix College, Andrea Rodriguez, Phoenix College, Olneya Fong, Phoenix College, Luis Saucedo, Arizona State University, Jonathan Wisman, Phoenix College, Evelyn Rivera, Phoenix College
Research has shown that water and microplastics contain trace amounts of substances known as contaminants of emerging concern (CECs). A few of these contaminants of Emerging Concern (CEC) frequently found in water include chemicals like prescription and non-prescription drugs microplastics, and biological contaminants, all of which pose global potential threats to the environment and health of humans. Some prevalent biological contaminants include Escherichia coli, Shigella, Salmonella, and Pseudomonas species. Pseudomonas aeruginosa can be found in the environment and has been capable of developing antibiotic resistance. According to the Centers for Disease Control and Prevention (CDC), multi-drug-resistant Pseudomonas aeruginosa led to over 32,000 hospitalizations, with 2,700 deaths in the United States in 2017 (CDC, 2019). As certain bacteria are naturally occurring flora that can be found in the environment and the gastrointestinal tract, it is hypothesized that biological contaminants, such as coliform bacteria and Pseudomonas species can persist throughout the water treatment process. To test this hypothesis, water samples were collected from 5 different stages of the wastewater treatment process at a Maricopa County wastewater treatment facility. The methodology used for this work consisted of collection, filtration, and quantitative analysis of biological contaminants using selective and differential media. Incubation of filtered samples on Maconkey and E. coli and Coliform (ECC) agar supported the hypothesis that gram-negative bacteria are present in wastewater samples. Additionally, to specifically identify the genus species of the selected isolates, additional biochemical analysis was performed using the GENIII Biolog MicroStation. This method compares the metabolic profile of the selected isolates to known aerobic and anaerobic bacteria, yeast, and fungi in the Biolog database. Preliminary data showed the presence of Serratia ficaria, Raultella, Klebsiella aerogenes, and Enterococcus canintestini in the wastewater samples. Species of the Raoultella bacteria have been discovered to cause food poisoning, acute gastroenteritis, and histamine poisoning. Klebsiella aerogenes and Enterococcus canintestini have been observed to cause urinary tract infections and meningitis, while Serra ficaria causes urinary and respiratory tract infections and sepsis. Additionally, FTIR analysis indicated antibiotic presence in the samples, raising concern about environmental microbes acquiring drug resistance. The determination of antibiotic susceptibility in the collected samples was conducted through drug resistance testing utilizing the Kirby-Bauer method. Observational data indicated resistance amongst stages. These preliminary findings warrant further investigation as these microbes have the potential to impact human health if not removed during the water treatment process.
Funder Acknowledgement(s): National Science Foundation (NSF), Arizona Department of Health Services, Phoenix College Bioscience Department, Arizona State University
Faculty Advisor: Robin Cotter, robin.cotter@phoenixcollege.edu
Role: My contribution to the research involved chemical and biological analysis over the course of a year. The chemical examinations included the filtration of samples, where filters were analyzed for microplastics using Nile Red dye, and chemicals were identified using FTIR (Fourier Transform Infrared Spectroscopy). In regard to the biological contaminants, I was made the lead researcher, overseeing the processing of all five stages of water samples on selective and differential media. Additionally, the identification of genus species through biochemical analysis facilitated by the Microstation Biolog system and the assessment of antibiotic resistance were conducted using the Kirby-Bauer method.