Lysinibacillus sphaericus (reclassified - previously known as Bacillus sphaericus) is a Gram-positive, mesophilic, rod-shaped bacterium commonly found on soil. It can form resistant endospores that are tolerant to high temperatures, chemicals and ultraviolet light and can remain viable for long periods of time. It is of particular interest to the World Health Organization due to the larvicide effect against some mosquitoes genera (Culex and Anopheles), more effective than Bacillus thuringiensis, frequently used as a biological pest control. It's important to highlight that it's uneffective against Aedes aegypti, an important vector of yellow fever and dengue viruses.
Within the species L. sphaericus it exists five homology groups (I-V), with group II further dividing into subgroups IIA and IIB. Due to the low levels of homology between groups, it has been suggested that each might represent a distinct species but owing to a lack of research on this topic, all remain designated as L. sphaericus.
The reclassification is based on the fact that the Lysinibacillus genus, in contrast to the type species of the genus Bacillus, contains peptidoglycan with lysine, aspartic acid, alanine and glutamic acide. 
Biological Pest Control
The insecticidal activity of L. sphaericus was first discovered in 1965 and further studies have shown mosquitoes to be the major target of this bacterium. There are reports of activity against other organisms such as the nematode Trichostrongylus colubriformis to which it has lethal effects on the eggs. It is of important use in mosquito control programs worldwide and has high specificity against mosquito larvae in addition to being safe for mammals, fish, birds and nondipterean insects. L. sphaericus is ineffective against Aedes aegypti, on the principal vector for many viral diseases, such as yellow fever and dengue.
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