Bed bugs modify microbiome of homes they infest

Microbes can affect indoor air quality. So NC State entomologists Coby Schal and Madhavi Kakumanu wanted to learn more about the microbiomes of bed bugs, whether bed bugs can shape the microbial community in homes they infest, and whether eliminating bed bugs changes the microbiome of homes that were once infested.

The study, held in an apartment complex in Raleigh, compared the microbiomes of bed bugs with the microbiomes in the household dust of infested homes as well as the microbiomes in apartments that had no bed bugs. Nineteen infested homes were studied over the course of four months; seven were treated with heat to eliminate bed bugs after the initial sample was taken, while 12 infested homes were treated after one month. These homes were compared with 11 homes that had no bed bugs.

The results showed similarities between the microbiomes of bed bugs and the dust-associated microbiomes of infested homes, mostly through the presence of Wolbachia, a symbiotic bacterium that comprises the majority of the bacterial abundance in bed bugs. Bed bug and infested home microbiomes differed significantly from the microbial communities of uninfested homes.

"There is a link between the microbiome of bed bugs and the microbiome of household dust in bed bug infested homes," said Schal, the Blanton J. Whitmire Distinguished Professor of Entomology at NC State and co-corresponding author of the paper. "No previous study has reported the impact of chronic pest infestations on indoor microbial diversity."

The study also showed that, after bed bugs were eliminated, infested home microbiomes gradually became more like those in homes without bed bugs.

"The elimination of the bed bugs resulted in gradual shifts in the home microbial communities toward those of uninfested homes," Kakumanu, an NC State research scholar in Schal's lab and co-corresponding author of the study, said. "This paper is the first experimental demonstration that eliminating an indoor pest alters the indoor microbiome toward that of uninfested homes."

"Bed bug infestations are problematic in many homes in both developed and developing countries," Schal said. "There is a critical need to investigate infestations from the perspective of indoor environmental quality, and this paper represents a first step toward this end."