A Nonlive Preparation of Chromobacterium sp. Panama (Csp_P) Is a Highly Effective Larval Mosquito Biopesticide

Abstract

Given the continued high prevalence of mosquito-transmitted diseases, there is a clear need to develop novel disease and vector control strategies. Biopesticides of microbial origin represent a promising source of new approaches to target disease-transmitting mosquito populations. Here, we describe the development and characterization of a novel mosquito biopesticide, derived from an air-dried, nonlive preparation of the bacterium Chromobacterium sp. Panama (family: Neisseriaceae). This preparation rapidly and effectively kills the larvae of prominent mosquito vectors, including the dengue and Zika vector Aedes aegypti and the human malaria vector Anopheles gambiae. During semi-field trials in Puerto Rico, we observed high efficacy of the biopesticide against field-derived A. aegypti populations, and against A. aegypti and Culex species larvae in natural breeding water, indicating the suitability of the biopesticide for use under more natural conditions. In addition to high efficacy, the nonlive Csp_P biopesticide has a low effective dose, a long shelf life, and high heat stability and can be incorporated into attractive larval baits, all of which are desirable characteristics for a biopesticide. IMPORTANCE We have developed a novel preparation to kill mosquitoes from an abundant soil bacterium, Chromobacterium sp. Panama. This preparation is an air-dried powder containing no live bacteria, and it can be incorporated into an attractive bait and fed directly to mosquito larvae. We demonstrate that the preparation has broad spectrum activity against the larval form of the mosquitoes responsible for the transmission of malaria and the dengue, chikungunya, yellow fever, West Nile, and Zika viruses, as well as mosquito larvae that are already resistant to commonly used mosquitocidal chemicals. Our preparation possesses many favorable traits: it kills at a low dosage, and it does not lose activity when exposed to high temperatures, all of which suggest that this preparation could eventually become an effective new tool for controlling mosquitoes and the diseases they spread.

The Axenic and Gnotobiotic Mosquito: Emerging Models for Microbiome Host Interactions

“…In the adult mosquito, C. violaceum exposure decreased the proportion of females seeking a blood meal, significantly reduced the numbers of eggs laid, and reduced hatches from the resulting eggs ( Gnambani et al, 2020 ). A preparation of a strain of Chromobacterium with no living cells maintained strong lethal effects in mosquitoes, indicating this bacterium was producing one or several bioactive compounds ( Caragata et al, 2020 ). Transcriptional analysis of mosquitoes with chromobacterium exposure revealed gene expression changes in pathways related to detoxification, xenobiotic response, and stress response, similar to that of an insecticide exposure ( Short et al, 2018b ).…”

Lipases secreted by a gut bacterium inhibit arbovirus transmission in mosquitoes

“…A soil bacterium named Chromobacterium sp . Panama ( Csp_P ) identified from the midgut of a field-caught Aedes aegypti showed strong virucidal activity against DENV [ 12 – 14 ]. In this study, we first identified a Chromobacterium from the gut of A .…”

Comprehensive Ecological and Geographic Characterization of Eukaryotic and Prokaryotic Microbiomes in African Anopheles

“…Current vector control tools are being challenged by insecticide resistance and vector behavioral shifts. In the past decade, studies of the mosquito prokaryotic microbiome have led to potential new vector control approaches, including bacteria exhibiting Plasmodium -blocking phenotypes ( Wang et al, 2017 ; Shane et al, 2018 ), the development of biopesticides from mosquito associated bacteria ( Lacey, 2007 ; Caragata et al, 2020 ), or population replacement using Wolbachia ( Ryan et al, 2019 ; Zheng et al, 2019 ). The eukaryotic members of the microbiome could also be useful to design similar or new approaches, such as interference or competition with Plasmodium superinfection, or as biological control agents.…”