In 1989, Bouvet and Jeanjean delineated five proteolytic genomic species (GS) of Acinetobacter, each with two to four human isolates. Three were later validly named, whereas the remaining two (GS15 and GS16) have been awaiting nomenclatural clarification. Here we present the results of the genus-wide taxonomic study of 13 human strains classified as GS16 (n=10) or GS15 (n=3). Based on core genome phylogenetic analysis, the strains formed two respective but closely related phylogroups within the Acinetobacter haemolytic clade. The intraspecies genomic average nucleotide identity based on blast (ANIb) values for GS16 and GS15 reached ≥94.9 % and ≥98.7, respectively, whereas ANIb values between them were 92.5-93.5% and those between them and the known species were ≤91.5 %. GS16 and GS15 could be differentiated from the other Acinetobacter species by their ability to lyse gelatin and sheep blood and to assimilate d,l-lactate, along with their inability to acidify d-glucose and assimilate glutarate. In contrast, GS16 and GS15 were indistinguishable from one another by metabolic/physiological features or whole-cell MALDI-TOF mass spectra. All the GS15/GS16 genomes contained genes encoding a class D β-lactamase, Acinetobacter-derived cephalosporinase and aminoglycoside 6'-N-acetyltransferase. Searching NCBI databases revealed genome sequences of three additional isolates of GS16, but none of GS15. We conclude that our data support GS16 as representing a novel species, but leave the question of the taxonomic status of GS15 open, given its close relatedness to GS16 and the small number of available strains. We propose the name Acinetobacter higginsii sp. nov. for GS16, with the type strain NIPH 1872T (CCM 9243T=CIP 70.18T=ATCC 17988T).

• Klíčová slova
• MALDI-TOF MS, carbon source assimilation, core genome phylogeny, whole genome sequence,
• MeSH
• Acinetobacter * MeSH
• DNA bakterií genetika   MeSH
• fylogeneze MeSH
• genomika MeSH
• hybridizace nukleových kyselin MeSH
• lidé MeSH
• mastné kyseliny chemie   MeSH
• ovce MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• techniky typizace bakterií MeSH
• zastoupení bazí MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• mastné kyseliny MeSH
• RNA ribozomální 16S MeSH

We studied the taxonomic position of six phenetically related strains of the genus Acinetobacter, which were recovered from hospital sewage in China and showed different patterns of resistance to clinically important antibiotics. Whole-genome sequencing of these strains and genus-wide phylogeny reconstruction based on a set of 107 Acinetobacter core genes indicated that they formed a separate and internally cohesive clade within the genus. The average nucleotide identity based on BLAST and digital DNA-DNA hybridization values between the six new genomes were 97.25-98.67% and 79.2-89.3%, respectively, whereas those between them and the genomes of the known species were ≤78.57% and ≤28.5%, respectively. The distinctness of the strains at the species level was also supported by the results of the cluster analysis of the whole-cell protein fingerprints generated by MALDI-TOF MS. Moreover, the strains displayed a catabolically unique profile and could be differentiated from the phylogenetically closest species at least by their inability to grow on d,l-lactate. A total of 18 different genes were found in the six genome sequences which encode resistance to seven classes of antimicrobial agents, including clinically important carbapenems, oxyimino-cephalosporins, or aminoglycosides. These genes occurred in five different combinations, with three to 10 different genes per strain. We conclude that the six strains represent a novel Acinetobacter species, for which we propose the name Acinetobacter cumulans sp. nov. to reflect its ability to acquire and cumulate diverse resistance determinants. The type strain is WCHAc060092T (ANC 5797T=CCTCC AB 2018119T=GDMCC 1.1380T=KCTC 62576T).

• Klíčová slova
• Carbon source assimilation, Core genome phylogeny, MALDI-TOF MS, Whole genome sequence,
• MeSH
• Acinetobacter chemie   klasifikace   účinky léků   genetika   MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální geny * MeSH
• DNA bakterií genetika   MeSH
• fylogeneze MeSH
• genom bakteriální genetika   MeSH
• hybridizace nukleových kyselin MeSH
• mnohočetná bakteriální léková rezistence genetika   MeSH
• nemocnice * MeSH
• odpadní vody mikrobiologie   MeSH
• peptidové mapování MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Čína MeSH
• Názvy látek
• antibakteriální látky MeSH
• DNA bakterií MeSH
• odpadní vody MeSH
• RNA ribozomální 16S MeSH

We recovered eight strains of the genus Acinetobacter from hospital sewage at West China Hospital in Chengdu, China. Based on the comparative analysis of the rpoB sequence, these strains formed a strongly supported and internally coherent cluster (intra-cluster identity of ≥98.0 %), which was clearly separated from all known Acinetobacter species (≤91.1 %). The eight strains also formed a tight and distinct cluster based on the genus-wide comparison of whole-cell mass fingerprints generated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In addition, the combination of their ability to assimilate 2,3-butanediol and phenylacetate, but not 4-hydroxybenzoate, and the inability to grow at 37 °C could distinguish these eight strains from all known Acinetobacter species. Whole-genomic sequencing has been performed for two selected strains, WCHA60T and WCHA62. There were 96.65 % average nucleotide identity (ANI) and 72 % in silico DNA-DNA hybridization (isDDH) values between WCHA60T and WCHA62, suggesting that the two strains indeed belonged to the same species. In contrast, the ANI and isDDH values between the two strains and the known Acinetobacter species were <83 and <30 %, respectively; both of which were far below the cut-off to define a bacterial species. Therefore, the eight strains should be considered to represent a novel species of the genus Acinetobacter, for which the name Acinetobacterwuhouensis sp. nov. is proposed. The type strain is WCHA60T (=CCTCC AB 2016204T=GDMCC 1.1100T=KCTC 52505T).

• Klíčová slova
• MALDI-TOF MS, metabolic properties, multilocus sequence analysis,
• MeSH
• Acinetobacter klasifikace   genetika   izolace a purifikace   MeSH
• DNA bakterií genetika   MeSH
• fylogeneze * MeSH
• hybridizace nukleových kyselin MeSH
• mastné kyseliny chemie   MeSH
• nemocnice * MeSH
• odpadní vody mikrobiologie   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• techniky typizace bakterií MeSH
• zastoupení bazí MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Čína MeSH
• Názvy látek
• DNA bakterií MeSH
• mastné kyseliny MeSH
• odpadní vody MeSH
• RNA ribozomální 16S MeSH

The bla(CTX-M-15) gene, encoding the globally dominant CTX-M-15 extended-spectrum β-lactamase, has generally been found in a 2.971-kb ISEcp1-bla(CTX-M-15)-orf477Δ transposition unit, with ISEcp1 providing a promoter. In available IncF plasmid sequences from Escherichia coli, this transposition unit interrupts a truncated copy of transposon Tn2 that lies within larger multiresistance regions. In E. coli, bla(CTX-M-15) is also commonly associated with IncI1 plasmids and here three such plasmids from E. coli clinical isolates from western Sydney 2006-2007 have been sequenced. The plasmid backbones are organised similarly to those of other IncI1 plasmids, but have insertions and/or deletions and sequence differences. Each plasmid also has a different insertion carrying bla(CTX-M-15). pJIE113 (IncI1 sequence type ST31) is almost identical to plasmids isolated from the 2011 E. coli O104:H4 outbreak in Europe, where the typical bla(CTX-M-15) transposition unit interrupts a complete Tn2 inserted directly in the plasmid backbone. In the novel plasmid pJIE139 (ST88), ISEcp1-blaC(TX-M-15)-orf477Δ lies within a Tn2/3 hybrid transposon. Homologous recombination could explain movement of ISEcp1-bla(CTX-M-15)-orf477Δ between copies of Tn2 on IncF and IncI1 plasmids and generation of the Tn2/3 hybrid. pJIE174 (ST37) is almost identical to pESBL-12 from the Netherlands and in these plasmids bla(CTX-M-15) is flanked by two copies of IS26 that truncate the transposition unit within a larger region bounded by the ends of Tn2. bla(CTX-M-15) and the associated ISEcp1-derived promoter may be able to move from this structure by the actions of IS26, independently of both ISEcp1 and Tn2.

• Klíčová slova
• IS26, ISEcp1, IncI1, Recombination, Tn2, bla(CTX-M-15),
• MeSH
• anotace sekvence MeSH
• beta-laktamasy genetika   MeSH
• beta-laktamová rezistence genetika   MeSH
• Escherichia coli enzymologie   genetika   MeSH
• plazmidy genetika   MeSH
• proteiny z Escherichia coli genetika   MeSH
• regulační oblasti nukleových kyselin MeSH
• replikace DNA MeSH
• sekvenční analýza DNA MeSH
• transpozibilní elementy DNA MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• beta-laktamasy MeSH
• proteiny z Escherichia coli MeSH
• transpozibilní elementy DNA MeSH