| dc.description.abstract | Escherichia albertii, first observed in 2003 as the causative agent in a diarrheal infection of a child in Bangladesh, is commonly misidentified as other Gram-negative pathogens such as E. coli, Shigella spp., and Salmonella enterica spp. E. albertii misidentification can lead to a mis-estimation of its impact in the food industry and on food safety. The goal of this research was to develop a novel selective enrichment broth to aid in its isolation and recovery from broiler tissue. Isolates underwent a NARMS Panel screening, identifying sulfamethoxazole, piperacillin, and trimethoprim as selective agents to be utilized in a selective enrichment formulation. Growth kinetics of E. albertii isolates 0065, ATCC 10457, 3542, 4085, and 3033 were assessed using varying concentrations of each listed antibiotics, then combinations of each antibiotic and bile salts. Data from growth kinetic experiments were used to plot a growth curve from which isolate doubling times were derived. Doubling times and visual observations of log/exponential phases produced were used to determine two selective enrichment formulations. E. albertii isolates were paired with other pathogens and inoculated into both formulation A (30.0 g dehydrated TSB, 2.5 g of bile salts, 34.0 µg/mL sulfamethoxazole, and 4.0 µg/mL trimethoprim) and formulation B (30.0 g TSB, 2.5 g bile salts, 4.0 µg/mL of piperacillin, and 4.0 µg/mL trimethoprim) to determine which medium produced better recovery. Samples positive for E. albertii were determined by a multiplex-PCR and biochemical assays. Results from multiplex PCR revealed no significant difference between the formulations (p=0.4775), although formulation A produced a higher rate of detection (6.02%) of E. albertii over formulation B. Recovery of E. albertii through biochemical assay resulted in 6.63% more positive E. albertii identifications using formulation A over B. The selective agent combination of sulfamethoxazole and trimethoprim is commonly utilized in clinical treatment for infections caused by enteric pathogens, which could be why formulation A produced better selectivity for E. albertii. The greater utility of selective enrichment formulation A will help in producing better recovery of E. albertii in food vehicles and the environment. | en |
