Genetic characterization of Chromobacterium isolates from black water environments in the Brazilian Amazon.

ABSTRACT

AIMS: To isolate and to characterize the diversity of Chromobacterium violaceum from the Brazilian Amazon region. METHODS AND RESULTS: Twenty-two isolates were obtained from the waters and banks of the river Negro, in the Brazilian Amazon. All isolates were able to grow in vitro at 44 degrees C and pH 4.0, but were adversely affected by temperatures below 15 degrees C, and unable to survive at 4 degrees C, properties that may be related to the adaptation to the ecosystem. The isolates were joined at a final level of similarity of only 13% in the rep-PCR analysis. The analysis of 16S rRNA genes resulted in three main groups clustered at a final level of similarity of 97% and only three isolates were clustered with the type strain. Similar data were obtained for the 23S rRNA gene. CONCLUSIONS: A high level of genetic diversity was verified with indications that the Brazilian isolates would fit into at least two new clusters besides C. violaceum species. SIGNIFICANCE AND IMPACT OF THE STUDY The results show remarkable bacterial adaptability and genetic diversity of C. violaceum in the Amazon region.