| Summary: | Aflatoxins are carcinogenic chemical metabolites produced by <i>Aspergillus</i> spp. of the section <i>Flavi.</i> In Kenya, <i>Aspergillus flavus</i> is the most prevalent and has been associated with several acute and chronic aflatoxin outbreaks in the past. In this study, we evaluated the occurrence of <i>A. flavus</i> in soils from two agro-ecological regions with contrasting climatic conditions, aflatoxin contamination histories and cropping systems. <i>Aspergillus</i> spp. were first isolated from soils before the identification and determination of their aflatoxigenicity. Further, we determined the occurrence of <i>Pseudomonas</i> and <i>Bacillus</i> spp. in soils from the two regions. These bacterial species have long been associated with biological control of several plant pathogens including <i>Aspergillus</i> spp. Our results show that <i>A. flavus</i> occurred widely and produced comparatively higher total aflatoxin levels in all (100%) study sites from the eastern to the western regions of Kenya. For the western region, <i>A. flavus</i> was detected in 4 locations (66.7%) that were previously under maize cultivation with the isolates showing low aflatoxigenicity. <i>A. flavus</i> was not isolated from soils under sugarcane cultivation. Distribution of the two bacterial species varied across the regions but we detected a weak relationship between occurrence of bacterial species and <i>A. flavus</i>. We discuss these findings in the context of the influence of climate, microbial profiles, cropping systems and applicability in the deployment of biological control remedies against aflatoxin contamination.
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