Isolation and characterization of entomopathogenic bacteria from soil samples from the western region of Cuba

Abstract

The use of insect pathogens is a viable alternative for insect control because of their relative specificity and lower environmental impact. The search for wild strains against dipterans could have an impact on mosquito control programs. We have made an extensive screening of soil in western Cuba to find bacteria with larvicidal activity against mosquitoes. A total of 150 soil samples were collected and isolates were identifying using the API 50 CHB gallery. Phenotypic characteristics were analyzed by hierarchical ascending classification. Quantitative bioassays were conducted under laboratory conditions following the World Health Organization protocol in order to ascertain the toxicity and efficacy of isolates. The protein profiles of the crystal components were determined by SDS-PAGE. Eight hundred and eighty-one bacterial isolates were obtained, and 13 isolates with entomopathogenic activity were isolated from nine samples. Nine isolates displayed higher entomopathogenic activity against both Cx. quinquefasciatus and Ae. aegypti compared with the reference strain 266/2. All toxic isolates showed higher biological potency than the 266/2 strain. These isolates with high entomopathogenic activity displayed a protein pattern similar to the B. thuringiensis var. israelensis IPS-82 and 266/2 strains. These results are a valuable tool for the control of Diptera of medical importance. Journal of Vector Ecology 38 (1): 46-52. 2013.

Effect of Chlorine and Temperature on Larvicidal Activity of Cuban Bacillus thuringiensis Isolates

“…A21, A51, L95, L910, M29, R84, R85, R87, R89, U81, X48 Cuban native isolates from soil samples of Cuba collected between 2007 and 2009 (8, 9). These isolates belongs to the entomopathogenic bacteria collection from the biological control laboratory of the Tropical Medicine Institute, “Pedro Kourí”, IPK, Cuba.…”

“…This lack of residual activity is due to the low stability of its Cry and Cyt toxins and the poor recycling of spores under field conditions (6, 7). Therefore the present study assessed the influence of temperature and water chlorination on the larvicidal activity of eleven B. thuringiensis Cuban native isolates (8, 9) in order to select the better isolates to control Ae. aegypti larvae in breeding sites.…”

Isolation, identification and evaluation of mosquito entomopathogenic Bacillus species and related genera from randomly selected sites in Kenya

“…However soil samples have shown greater richness in the diversity of Bacillus species and related genera compared to other sources making it the most preferred substrate for isolation (González et al, 2013;Lobo et al, 2017;Suryadi et al, 2016). In this study, 453 Bacillus strains and related genera were isolated from 100 soil samples collected from random Strain PCR results 16s rRNA binA binB mtx1 mtx2 mtx3 cry48A cry49A cry4A cry11A cyt1A Ls C3-41 Positive; -, Negative. sites in Kenya.…”

“…During the past decades, synthetic insecticides such as organophosphate insecticides have been used to control mosquito populations, but their wide application has been greatly obstructed due to environmental pollution, resistance in the vectors and harmful effects on beneficial non-target animals (González et al, 2013;Irungu et al, 2016;Peralta and Palma, 2017).…”

“…israelensis are currently the most commonly and widely used mosquito control agents due to their specific toxicity against mosquitoes and the compatibility in the environment (Pei et al, 2002;Yuan et al, 2003;González et al, 2013;Suryadi et al, 2015). The pathogenicity of L. sphaericus and B. thuringiensis var.…”