Phylogenetic Diversity of Bacterial Communities Associated with Sulfurous Karstic Well Waters of a Hungarian Spa

Abstract

The composition of bacterial communities associated with waters of one thermal and three sulfurous lukewarm wells of cavernous limestone aquifers in the Southwestern part of Hungary was studied in 2007 and 2008 by microscopy and culture-independent clone library analysis targeting the 16S rRNA gene. The presence of Thiothrix-like filamentous bacteria was observed by microscopy in the lukewarm samples. From the clone libraries, a high proportion of phylotypes belonging to Proteobacteria (Rhodobacter, Sphingopyxis, Phenylobacterium, Ochrobactrum, Methylobacterium, Sulfuritalea, Thiobacillus, Limnobacter, Acidovorax, Xanthomonadaceae, Thiothrix, Lysobacter, Pseudoxanthomonas, Desulfopila, Desulfocapsa, Desulforhopalus, Sulfuricurvum, Sulfurimonas, Sulfurospirillum) was revealed. In addition, phylotypes of Acidobacteria, Chloroflexi, Sphingobacteria, Clostridia, Aquificae, Deferribacteres and Chlorobi were detected. On the basis of their habitat preference 21 out of a total of 39 different phylotypes represented mesophilic and thermophilic sulfur bacteria. From the lukewarm samples large numbers of clones were affiliated with uncultured Epsilonproteobacteria clones common in sulfurous hydrothermal vents. From the thermal sample, several clones were in the closest relationship to the Sulfuritalea hydrogenivorans, a novel sulfur-oxidizing Betaproteobacterium.

Keywords:

• sulfurous well water
• bacterial diversity
• clone library
• 16S rDNA sequence analysis

Acknowledgments

We would like to thank the management of Harkány Spa for providing physical and chemical data. We are indebted to the members of the Microbiology Laboratory of the National Health Service in Pécs for laboratory support. In addition, we would like to thank the technical crew of Harkány Spa for the help in sampling.