Document Type


Publication Date

October 2014


Identification and characterization of viable-culturable bacteria (VCB) associated with soils from Africa and the Americas is significant for environmental and battlefield security. Such analyses are scarce and their evaluation using traditional microbiological methods do not fully elucidate the structure and chemotaxonomic characteristics of the microbial community. In this study, matrix assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS) spectrometry in addition to 16S rRNA sequencing, and diversity indices were employed to characterize VCB and their associated biomarkers. Nineteen genera were identified across all sample locations, but only four (Bacillus, Brevibacillus, Paenibacillus and Terribacillus) confirmed by ClustalW2 as being 98-99% similar among locations. Further evaluation of soils showed bacteria diversity (H) of (1.0-8.4), evenness (EH), (0.14-0.72), similarity (Sj), (0.0-0.38) and cfu/g soil (2.5 × 101 - 2.2 × 107). Analysis of representative bacteria using MALDI-TOF MS identified biomarkers for the following genera: Bacillus, m/z 6778 (75%), 9437 (100%); Brevibacillus, m/z 7381 (86%); Paenibacillus, 5473 (63%) and Terribacillus, 4517, 6532, 7574 (67%). Peptide mass fingerprinting (PMF) of biomarkers identified partial peptide maps for several potential virulence factors such as hemagglutinin (HA) from a Brevibacillus spp. The data indicates an east (Sudan) to west (Jamaica; Mexico; Washington, DC; Baltimore) trend of potentially pathogenic endospore-forming-bacteria.

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