Collateral Sensitivity-Informed Antibiotic Combinations for Klebsiella pneumoniae infections

Abstract

The resistance of Klebsiella pneumoniae to third-generation cephalosporins is a serious issue in public health and calls for novel approaches to treatment. The possibility of using antibiotic combinations that are informed by collateral sensitivity as a treatment strategy is investigated in the present study. Collateral sensitivity is defined as the process where the acquisition of resistance to one antibiotic produces increased susceptibility to a second antibiotic. Through two-step conjugations, we inserted seven IncF plasmids into K. pneumoniae ATCC43816 and evaluated the effect of horizontal gene transfer on antibiotic susceptibility and bacterial fitness. The MICs of ten distinct antibiotics were determined by comparing plasmid-carrying strains with the wild type. After we determine which IncF harboring KP strains present collateral sensitivity responses to specific antibiotics, we will exploit these findings to inform effective treatment. Therefore, the concentration of antibiotics that will be used to treat infection caused by IncF harboring KP will be lower than the one used for infection caused by KP WT. Our results showed major shifts in susceptibility profiles towards chloramphenicol, colistin, fusidic acid, nitrofurantoin and rifampicin, with these antibiotics showing improved efficiency against bacteria carrying plasmids, indicating collateral sensitivity effects. Furthermore, time-kill assays showed that the usage of concentration equal to the MIC of IncF harboring KP resulted in eliminating this strain while KP WT was not affected in the same way, as far as their growth curves and bactericidal or bacteriostatic dynamics over time are concerned. Whereas fitness assays revealed varying influences on bacterial growth dynamics, indicating the fitness cost of harboring IncF megaplasmids. In all, these findings demonstrate the potential of using collateral sensitivity to create treatment plans which are more effective than existing conventional ones.