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Antibiotic resistance is a growing epidemic from excessive use of available antibiotics that is leading to a global health crisis. As more antibiotics are being misused, killing susceptible bacteria, more resistant bacteria grow to be prominent in the population. Given the ability of bacteria to exchange genetic information, high prevalence of antibiotic resistance poses a great threat to make killers out of bacteria that were formerly treatable. Grasshoppers are critical players in the ecosystem serving as a connector between soil, plant, and animal. Grasshoppers are also the most consumed insect by humans. Therefore, if grasshoppers can serve as a vector to spread antibiotic resistance in the environment, they might provide a potential target to halt the antibiotic resistance epidemic. In this study, we examined whether antibiotic resistant bacteria are present in a wild grasshopper. A male grasshopper was dissected and its gut content was diluted and plated on LB agar. Different bacterial isolates were obtained. To test for antibiotic susceptibility in these bacteria, disc diffusion assays were performed by spreading the bacterial isolate on LB agar and placing discs that contain antibiotics Rifampin, Streptomycin, and Penicillin on the agar. After 24 and 48 hours, the diameter of the growth inhibition zone was measured in mm. The bigger the diameter, the more susceptible the bacteria are to the antibiotic. Out of the 17 isolates, only three were susceptible to Penicillin, demonstrating that there was a high level of Penicillin resistance. In contrast, 16 out of 17 isolates show susceptibility to Rifampin. Fewer isolates are susceptible to Streptomycin but the diameter for the zone of inhibition was larger. From these results, it is clear that antibiotic resistant bacteria are indeed present in the grasshopper, potentiating grasshoppers as a vehicle of antibiotic resistance transmission.

Publication Date


Project Designation

Independent Research

Primary Advisor

Yvonne Y Sun

Primary Advisor's Department



Stander Symposium poster


Presenters: Lauryn E Brasch, Melani Muratore

Antibiotic Resistance to Rifampin, Streptomycin, and Penicillin in Grasshopper Bacterial Isolates