Molecular identification and knockdown resistance mutation of bed bugs involved in 2019 outbreak in Cape Coast, Ghana and Munich, Germany

The worldwide resurgence of bed bug infestations is worrisome, particularly with the co-infestation of the two common bed bug species and emergence of insecticide resistance. For effective management, information on the specific species and their insecticide resistance status is crucial. This study investigated the specific species and knockdown resistance (kdr) gene mutations of the bed bug populations from Cape Coast, Ghana and Munich, Germany evolved in the 2019 infestation outbreak. Bed bugs were collected in households and educational institutions in Cape Coast, Ghana and a refugee shelter in Munich, Germany during the infestation outbreak in 2019. The susceptibility status of the bed bugs to four public health insecticides was determined using the standard WHO bioassay. Polymerase chain reaction (PCR) amplification of cytochrome oxidase subunit I (COI) gene and voltage-gated sodium channel (VGSC) gene followed by Sanger sequencing was used to identify the species and kdr mutations among the bed bugs collected. The bed bugs in Ghana were found to be two subpopulations of C. hemipterus, both of them harboring the M918I and L1014F kdr mutations. In addition, the population was extremely resistant to organochlorine, pyrethroid, carbamate and organophosphate insecticides. The bed bug population in Germany was a single population of C. lectularius with the L925I kdr mutation. This is the first report of the detection of multiple kdr mutations in C. hemipterus from Sub-Saharan Africa. The extreme resistance of the insect to the major classes of insecticides is a cause of concern and could have serious public health implications.