Journal of Bacteriology & Parasitology

Characterization of novel Bacillus Thuringiensis strains native to Saudi Arabia with enhanced larvicidaltoxicity against the malaria mosquito Anopheles Gambiae S.L

3^rd International Congress on Bacteriology and Infectious Diseases

August 04-06, 2015 Valencia, Spain

Talat A El-kersh1, Ashraf M Ahmed1, Yazeed A Al-sheikh1, Frédéric Tripet2, Mohamed S Ibrahim1 and Fahd A Al-Mekhlafi1

Posters-Accepted Abstracts: J Bacteriol Parasitol

Abstract:

The bacterium Bacillus thuringiensis(Bt) is a safe eco-friend entomopathogenicbiocontrol agent widely used to complement
chemical control. Hence there is an urgent need for characterizing novel isolates with potent larvicidal activity against
mosquito vectors.The present study was initiated to characterize new native Bt isolates with mosquitocidal activity from various
samples from 16 regions across the Saudi Arabia.Various samples were collected from mosquito breeding sites across different
regions in in the country and screened for Bt isolation. Bt isolates were characterized on the basis of colony morphology, shape
of spores and parasporal crystals and through comparisons of biochemical profiles. The larvicidal activity (LC50& LC95) of
standardized spore/crystal mixtures of Bt isolates were tested against larvae of Anopheles gambiae. At24hour post-treatment
and compared with that of the Bt.israelensis (Bti-H14).A total of 23 (out of 68 native Bt isolates) were mosquitocidal. Larvicidal
strains were similar in terms of colony morphology, hemolytic and motile. Out of the 23 isolates, 9 showed significantly higher
activity (LC50 range from 3.90 to 9.5μg/ml) than the Bti-H14 (LC50 of 13.33 μg/ml) with one strain having as much as 3.4-fold
higher activity than the Bti-H14. This is the first report of Bt strains native to Saudi Arabia with significantly enhanced larvicidal
efficacy against the malaria mosquito An. gambiae. These novel Bt strains may therefore contribute to novel potent biopesticides
and help mitigate the risk of Bt resistance emergence in bio-control programs targeting malaria vector populations.