2025/07/07 by Roberta Sauerborn Klobučar, Maja Kovačević, Ema Svetličić +15 · 1 voice
Biochemistry, Genetics and Molecular Biology · Dentistry · #Bacterial biofilms and quorum sensing #Legionella and Acanthamoeba research #Oral microbiology and periodontitis research
paper · doi:10.1099/ijsem.0.006813
openalex created_date 2025/07/07 · openalex publication_date 2025/07/07 · openalex updated_date 2026/06/11
Legionella- like isolates, HB10 and PATHC038 T , were isolated from a cold water distribution system on a cruise ship in 2017. The strains have been characterized by employing discriminatory genome typing, matrix-assisted laser desorption/ionization time-of-flight MS technique, fatty acid profiling and biochemical tests, thus identifying a new species in the genus Legionella . Colonies displayed phenotypic characteristics typical of the family Legionellaceae , including a requirement for l -cysteine and testing catalase positive. Fatty acid methyl ester analysis showed that the predominant fatty acids detected in the studied strains are C16:0 iso, C16:1 ω 7 c , C16:0 and C15:0 anteiso. The obtained MIC values showed antimicrobial susceptibility to the antimicrobial drugs ciprofloxacin and erythromycin (0.8 and 2 µg ml −1 , respectively). The bacteria were also Gram-negative, rod-shaped, grew aerobically on buffered charcoal yeast extract agar and weakly grew on glycine-vancomycin-polymyxin-cycloheximide media at 36 °C with the ability to autofluoresce a blue-white colour when placed under a long-wavelength UV light (365 nm). The whole-genome sequencing performed displayed a G+C content of 38.2 mol%. The digital DNA–DNA hybridization analysis demonstrated a separation from the phylogenetically most related Legionella cherrii , with 54.7% DNA–DNA relatedness. The identity percentage measured by average nucleotide identity between the PATHC038 T strain and its respective closest species, L. cherrii , was 93.9%, also confirming the distinctiveness of the novel species. The 16S rRNA gene, mip and rpoB sequences showed a similarity of 98.7, 98.4 and 96.2%, respectively, with L. cherrii NCTC 11976 T . Additionally, average amino acid identity and percentage of conserved proteins analyses further supported their classification as a novel species. The results obtained in this study confirm the status of an independent species. The name proposed for this species is Legionella sheltonii sp. nov. with PATHC038 T (CCUG 76918T, ATCC TSD-370) as the type strain.