Exposure to commercial formulation of the Pesticide Carbofuran induces resistance to Cephalosporin drug in Pseudomonas aeruginosa: an in vitro study

Abstract

Antibiotic resistance occurs when pathogenic bacteria acquire the mechanism to persist in a higher concentration of bactericidal or bacteriostatic substances. Misuse and overuse of antibiotics are assumed to be responsible for emergence of antibiotic resistance for decades. Recently, scientists suggested that the selective pressure of pesticides in the natural environment may play a strong role in the emergence of antibiotic resistance. In this study, we intend to understand the effect of pesticide carbofuran on antibiotic resistance. Pseudomonas aeruginosa was used as a model organism for the experiments. The strain was exposed to commercial formulation of the pesticide carbofuran in four different concentrations according to environmental residual value. Following five days of exposure, antibiotic susceptibility testing of the exposed strains was done. The reference strain was previously resistant to antibiotics from six major classes of antibiotics: doxycycline, amoxycillin, co-trimoxazole, erythromycin, clindamycin, and vancomycin. Susceptibility against other three antibiotics remained unaffected including streptomycin, moxifloxacin, and meropenem. Only antibiotic susceptibility against antibiotic cefepime was affected by the exposure of carbofuran. The exposure to commercial formulation of carbofuran increased minimum inhibitory concentration of cefepime up to 150-folds. Additionally, the strain conferred resistance against antibiotic ceftriaxone which indicates the capacity of carbofuran to induce cephalosporin drug resistance in Pseudomonas aeruginosa. The resistance mechanism is subject to further analysis.