Delineation of a novel environmental phylogroup of the genus Acinetobacter encompassing Acinetobacter terrae sp. nov., Acinetobacter terrestris sp. nov. and three other tentative species

Alexandr Nemec, Lenka Radolfová-Křížová, Martina Maixnerová, Matěj Nemec, Petra Španělová, Renata Šafránková, Ondrej Šedo, Bruno S. Lopes, Paul G. Higgins

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2 Citations (Scopus)


This study aimed to define the taxonomic position and structure of a novel, taxonomically unique group of 26 Acinetobacter strains, provisionally designated Taxon 24 (T24). The strains were recovered from soil and freshwater ecosystems (n = 21) or animals (n = 5) in Czechia, Scotland, Germany, the Netherlands and Turkey between 1993 and 2015. They were non-glucose-acidifying, nonhemolytic, nonproteolytic, growing at 32 °C and on acetate and ethanol as single carbon sources, but not on 4-hydroxybenzoate and mostly not at 37 °C. Their whole-genome sequences were 3.0–3.7 Mb in size, with GC contents of 39.8–41.3%. Based on core genome phylogenetic analysis, the 26 strains formed a distinct clade within the genus Acinetobacter, with strongly supported subclades termed T24A (n = 11), T24B (n = 8), T24C (n = 2), T24D (n = 3) and T24E (n = 2). The internal genomic ANIb values for these subclades were >94.8%, while the ANIb values between them were <92.5%. The results of MALDI-TOF MS-based analyses agreed with this classification. The five subclades differed from each other in the results of one to six carbon source assimilation tests. Given the genomic and phenotypic distinctness, internal coherence, numbers of available strains and geographically diverse origin of T24A and T24B, we propose the names Acinetobacter terrae sp. nov. and Acinetobacter terrestris sp. nov. for these two taxa, respectively. The type strains are ANC 4282v (= CCM 8986T = CCUG 73811T = CNCTC 8082T) and ANC 4471T (= CCM 8985T = CCUG 73812T = CNCTC 8093T), respectively. We conclude that these two species together with the other T24 strains represent a widely dispersed Acinetobacter clade primarily associated with terrestrial ecosystems.

Original languageEnglish
Article number126217
JournalSystematic and Applied Microbiology
Issue number4
Early online date24 May 2021
Publication statusPublished - 6 Jun 2021

Bibliographical note

Funding Information:
The work was partially supported by MH CZDRO (National Institute of Public Health – NIPH, 75010330). CIISB, Instruct-CZ Centre of Instruct-ERIC EU consortium, funded by MEYS CR infrastructure project LM2018127, is gratefully acknowledged for the financial support of the measurements at the CEITEC Proteomics Core Facility. Computational resources for genomic analysis were supplied by the project "e-Infrastruktura CZ" (e-INFRA LM2018140) provided within the program Projects of Large Research, Development and Innovations Infrastructures.

Funding Information:
We thank Lenie Dijkshoorn (Leiden Medical Centre, the Netherlands) and Harald Seifert (University of Cologne, Germany) for generous provision of strains and Eva Kodytkov? (National Institute of Public Health, Prague, Czechia) for linguistic revision of the manuscript.

Publisher Copyright:
© 2021 Elsevier GmbH


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