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Environmental Effects Triggering Antibiotic Resistance in Bacteria
BROOKE SMITH, Maria King, Texas A&M University
Abstract Number: 201
Working Group: Bioaerosols
Abstract
The world is currently in an antibiotic crisis due to the development of antibiotic resistance in bacteria. Antibiotic resistance poses a threat in many institutions such as hospitals, meat processing units and other agricultural and occupational entities. This study focuses on the environmental factors that may cause Escherichia coli (E. coli) MG 1655 to express antibiotic resistance genes (ARGs). These conditions include temperature, relative humidity, the absence or presence of light, airflow and duration of aerosolization. The fresh mid-log phase bacterial suspensions were aerosolized by the 6-jet Collison atomizer for 5, 10, 15, 30 and 45 minute periods into a 27 L sterile box at constant airflow of 80 L/min and collected using the 100 L/min wetted wall cyclone bioaerosol collector that maintains the culturability of the bacteria. Each sample was analyzed and compared based its response to each environmental factor by susceptibility testing and polymerase chain reaction using specific primers to target different ARGs (marR, rfaC, katE). The goal of this research is to uncover how bacteria react to certain environmental conditions, and delineate the factors that may trigger resistance. The Kirby Bauer susceptibility test results indicated the strongest resistant response to ampicillin, cephalothin, and gentamicin, which are cell wall or protein synthesis inhibitors. More resistance was detected in E. coli aerosolized for 5 minutes versus 45 minutes, but a similar number of resistant E. coli was found in the 15 minute and 30 minute aerosolizations indicating that after 30 min period the bacterium didn’t respond further to the increased amount of aerosolization stress. However, high susceptibility was maintained to imipenem and cefoperazone, both cell wall synthesis inhibitors, in all nebulization durations. This information will help mitigating antibiotic resistance in bacteria by optimizing environmental conditions to prevent the development of ARGs.