Numerical Taxonomy of Moderately Halophilic Gram-negative Rods

TLDR

The authors examined 516 isolates from solar salterns, selected 106 for detailed cytological, physiological, biochemical, nutritional, and antibiotic‑sensitivity profiling, and applied Jaccard similarity and UPGMA clustering to classify the strains. Clustering revealed nine major phenons at 72.5 % similarity, most strains affiliating with marine genera and many tentatively assigned to Vibrio, indicating that Vibrio may be a dominant moderately halophilic Gram‑negative rod in solar salterns.

Abstract

A study was made of 516 randomly selected isolates of moderately halophilic bacteria from solar salterns showing salinities between 8·8 and 40·0% (w/v) total salts, located in S.E. Spain. After purification, many cytological, physiological, biochemical, nutritional and antibiotic sensitivity characters were determined for 106 selected saltern isolates and two reference strains. Data were coded and analysed by numerical techniques using the Jaccard coefficient (SJ ), and clusters of strains were obtained by average linkage (UPGMA) analysis. Nine major phenons were found at the 72·5% similarity level. The properties of each phenon are given, their taxonomic affinities are discussed, and typical reference strains are suggested. Almost all the strains were related to genera known to contain marine species. A large number of the strains could be tentatively assigned to the genus Vibrio, suggesting that this may be an abundant taxon of moderately halophilic Gram-negative rods in solar salterns.