Reservoir of Bacterial Exotoxin Genes in the Environment

Abstract

This is the first report of an environmental reservoir of a bacterial exotoxin gene harbored in an atypical host in the environment. Screening bacterial isolates from the environment via seaspecific PCR identified an isolate with a DNA sequence >95% identical to the Staphylococcus aureus enterotoxin A gene (sea). 16S DNA sequence comparisons identified the environmental isolate as a Pseusodomonad. Laboratory studies confirmed that this Pseudomonad is psychrophilic. The results indicate that the sea gene is present in an alternative bacterial host, providing the first evidence for an environmental reservoir of exotoxin genes in bacteria. Transfer of these genes between phage and alternative bacterial hosts may promote the evolution of novel human diseases.

Occurrence and expression of bacterial human virulence gene homologues in natural soil bacteria

“…Casas et al . () cultured bacteria from ambient air and screened these for the presence of the Staphylococcus aureus exotoxin A gene, sea . In one isolate, a Pseudomonas , the sea gene was detected.…”

Caenorhabditis elegans: a model to monitor bacterial air quality

“…However, the identification of microbial species and strain is not sufficient to extrapolate at the sanitary risk level, as many different parameters may affect virulence. Indeed, both contact mediated and toxin dependent virulence are regulated by environmental conditions including temperature [ 15 ], bacteriophages [ 16 ] and of course microbial communication factors [ 17 ]. Sometimes bacterial strains are generally considered safe and devoid of pathogenic potential and, however, induce clinical infections [ 18 , 19 ].…”