Legionella bononiensis sp. nov., isolated from a hotel water distribution system in northern Italy.

Legionella -like isolates, strains 27fs60, 30fs61 and 30cs62 ^T , were isolated from a hotel water distribution system in the Emilia-Romagna region, Italy. Isolates were Gram- and Ziehl Neelsen-stain-negative, rod-shaped, with transitory flagella presence and able to grow at 32-37 °C (with an optimum at 32 °C) on buffered charcoal-yeast extract agar with l-cysteine, glycine-vancomycin-polymyxin B-cycloheximide agar and Wadowsky-Yee medium agar. The strains showed positive reactions for oxidase, hippurate and gelatinase and a weakly positive reaction for catalase. Based on the EUCAST cut-off, strain 30cs62 ^T was resistant to ciprofloxacin (5 mg l ^-1 ). The mip and rpoB gene sequences of the three strains showed close matches to those of Legionella quateirensis ATCC 49507 ^T with similarity values of 98.2 and 94.5 %, respectively. Whole genome sequencing of the three strains was performed, resulting in G+C contents of 39.0, 39.1 and 39.0 mol%, respectively. The identity percentage measured by average nucleotide identity between the three strains and their respective closest strains were: 91.32 % L . quateirensis NCTC 12376 ^T , 91.45 % L . quateirensis ATCC 49507 ^T and 91.45 % L . quateirensis ATCC 49507 ^T , respectively. The digital DNA-DNA hybridization analysis demonstrated how the isolates were separated from the most related phylogenetic Legionella species ( L. quateirensis ATCC 49507 ^T , ≤40.10 % DNA-DNA relatedness). The concatenated phylogenetic tree based on 16S rRNA , mip, rpoB and rnpB genes, shows a close relationship with L. quateirensis ATCC 49507 ^T . The results obtained confirm the status of an independent species. The name proposed for this species is Legionella bononiensis sp. nov. with 30cs62 ^T (=ATCC TSD-262 ^T =DSM 112526 ^T ) as the type strain.