A new study published on March 27 in the Journal of Economic Entomology reveals that bed bugs undergo metabolic detoxification where they break down insecticides using the enzymes esterases and oxidases. Apparently, these two enzymes change the insecticides’ chemical composition, making pyrethroid insecticides less harmful to the bugs.
The researchers had to use chemicals called synergists to determine which enzymes provide the bed bugs’ resistance. They used two types; one was chemical called piperonyl butoxide (or PBO) and the other one was EN16/5-1, a new type of synergist.
These chemicals can reduce the levels of the detoxifying enzymes, making the insecticides more effective. Specifically, the piperonyl butoxide lowers both esterases and oxidases while the EN16/5-1 only inhibits oxidases and not esterases.
The research team studied 200 bed bugs and exposed these two six different treatments. These treatments included using each of the synergist, as well as a combination of insecticide and synergist.
The researchers observed that presence of both PBO and EN16/5-1 significantly enhanced the efficacy of the insecticide in many bed bugs strains. On the other hand, adding only EN16/5-1 did not work in some strains.
This suggested that different bed bugs strains have different metabolic enzymes, with some having only oxidases, some only esterases and others with both. The findings may have many consequences in the fight against bed bug infestation in the future.
“The findings of this research are particularly important, as metabolic resistance is often known to confer ‘cross resistance,’ whereby resistance to one chemical group can result in resistance to a whole range of different insecticides, which limits what we can use now and even in the future for controlling bed bugs,” says co-author Stephen Doggett. “This emphasises the need for an integrated approach to bed bug control using all of the available tools, both chemical and non-chemical.”