Alcaligenes faecalis BUMCn01: a new bacterial isolate larvicide against filarial vector Culex quinquefasciatus.

backgroundMosquito-borne diseases continue to pose major public health challenges, necessitating the development of environmentally safe biological control agents. Although several bacterial larvicides are currently used, novel gut-associated bacteria with high specificity and low non-target toxicity remain under-explored. This study (This is the first report demonstrating mosquito larvicidal activity of Alcaligenes faecalis against Culex quinquefasciatus larvae.) reports, for the first time, the mosquito larvicidal potential of Alcaligenes faecalis against Culex quinquefasciatus larvae.

methodsA bacterial (This is the first report demonstrating mosquito larvicidal activity of Alcaligenes faecalisagainst Culex quinquefasciatus larvae.) isolate, obtained from the midgut of naturally dead and moribund Cx. quinquefasciatus larvae, was identified as Alcaligenes faecalis strain BUMCn01 (GenBank accession: PX526002) based on morphological, biochemical, physiological, and 16S rRNA gene analyses. Larvicidal bioassays using A. faecalis strain BUMCn01 formulation were performed against all four larval instars. Bacterial localization and aggregation in the larval midgut following exposure to A. faecalis strain BUMCn01 were examined by scanning electron microscopy. Field efficacy was evaluated in sewage drains of different depths. Laboratory evaluations of the A. faecalis strain BUMCn01 formulation was also conducted on non-target aquatic organisms (Chironomus circumdatus larvae, Daphnia spp., Poecilia reticulata, and tadpoles of Bufo spp.). Furthermore, bacterial proteins were isolated and assessed for larvicidal efficacy against 3

resultsThe isolate was identified as Alcaligenes faecalis strain BUMCn01 using a polyphasic approach including morphological, biochemical, physiological and 16S rRNA gene sequence analysis (GenBank accession: PX526002).The Alcaligenes faecalis BUMCn01 formulation resulted in clear dose-response relationship. 100% mortality was recorded in 1

conclusionsThis study provides the first evidence that (The isolate was identified as Alcaligenes faecalis strain BUMCn01 using a polyphasic approach including morphological, biochemical, physiological, and 16S rRNA gene sequence analysis (GenBank accession: PX526002).) Alcaligenes faecalis strain BUMCn01 exhibits significant larvicidal activity against Culex quinquefasciatus. Bacterial proteins appear to be the primary toxic agent. The Alcaligenes faecalis BUMCn01 formulation showed significant efficacy in laboratory and field trials with minimal non-target toxicity, supporting its potential use as a microbial larvicide in integrated mosquito management.