We aimed to define the taxonomic status of 16 strains which were phenetically congruent with Acinetobacter DNA group 15 described by Tjernberg & Ursing in 1989. The strains were isolated from a variety of human and animal specimens in geographically distant places over the last three decades. Taxonomic analysis was based on an Acinetobacter-targeted, genus-wide approach that included the comparative sequence analysis of housekeeping, protein-coding genes, whole-cell profiling based on matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), an array of in-house physiological and metabolic tests, and whole-genome comparative analysis. Based on analyses of the rpoB and gyrB genes, the 16 strains formed respective, strongly supported clusters clearly separated from the other species of the genus Acinetobacter. The distinctness of the group at the species level was indicated by average nucleotide identity values of ≤82 % between the whole genome sequences of two of the 16 strains (NIPH 2171(T) and NIPH 899) and those of the known species. In addition, the coherence of the group was also supported by MALDI-TOF MS. All 16 strains were non-haemolytic and non-gelatinase-producing, grown at 41 °C and utilized a rather limited number of carbon sources. Virtually every strain displayed a unique combination of metabolic and physiological features. We conclude that the 16 strains represent a distinct species of the genus Acinetobacter, for which the name Acinetobacter variabilis sp. nov. is proposed to reflect its marked phenotypic heterogeneity. The type strain is NIPH 2171(T) ( = CIP 110486(T) = CCUG 26390(T) = CCM 8555(T)).

• MeSH
• Acinetobacter klasifikace   genetika   izolace a purifikace   MeSH
• bakteriální geny MeSH
• DNA bakterií genetika   MeSH
• fylogeneze * MeSH
• hybridizace nukleových kyselin MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
• techniky typizace bakterií MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH

OBJECTIVES: Sulbactam is well known to have clinically relevant intrinsic activity against Acinetobacter baumannii. Although secondary resistance to this drug has long been reported in acinetobacters, virtually nothing is known about its molecular basis. The aim of this study was to test the hypothesis that β-lactamase TEM-1 is responsible for sulbactam resistance in A. baumannii. METHODS: Seventeen clinical strains of A. baumannii were selected to represent different combinations of quantitative susceptibilities to sulbactam and molecular typing characteristics. The strains were screened by PCR for the presence of the blaTEM-1 gene and its variants. Amplicons encompassing the blaTEM genes, including their promoters, were sequenced. The expression and copy number of the blaTEM genes were assessed using semi-quantitative real-time PCR. Transfer of the blaTEM-1 gene into a susceptible A. baumannii strain was achieved by electroporation. RESULTS: Six strains were negative for the blaTEM gene and had sulbactam MICs of 0.5-1.0 mg/L, 10 strains harboured blaTEM-1 and showed MICs ≥ 8.0 mg/L, except for one strain with an MIC of 2 mg/L, while the remaining strain carried blaTEM-19 and had an MIC of 1 mg/L. The level of blaTEM-1 expression positively correlated with the MICs of sulbactam (r = 0.92). Promoter P4 was linked to the blaTEM gene in all strains except for a P3-carrying strain (an MIC of 2 mg/L). Transformation of the susceptible A. baumannii strain with blaTEM-1 resulted in a 64-fold increase in sulbactam MIC and in resistance to ticarcillin and piperacillin, but no change in susceptibility to broad-spectrum generation cephalosporins, aztreonam or carbapenems. CONCLUSIONS: The results presented suggest that TEM-1 represents a clinically relevant mechanism of sulbactam resistance in A. baumannii.

• MeSH
• Acinetobacter baumannii účinky léků   enzymologie   izolace a purifikace   MeSH
• bakteriální léková rezistence * MeSH
• beta-laktamasy antagonisté a inhibitory   genetika   sekrece   MeSH
• DNA bakterií genetika   MeSH
• genová dávka MeSH
• infekce bakteriemi rodu Acinetobacter mikrobiologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• lidé MeSH
• polymerázová řetězová reakce MeSH
• sekvenční analýza DNA MeSH
• stanovení celkové genové exprese MeSH
• sulbaktam farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• Acinetobacter baumannii enzymologie   genetika   izolace a purifikace   MeSH
• beta-laktamasy genetika   MeSH
• genotyp MeSH
• infekce bakteriemi rodu Acinetobacter mikrobiologie   MeSH
• lidé MeSH
• mnohočetná bakteriální léková rezistence * MeSH
• molekulární typizace MeSH
• multilokusová sekvenční typizace MeSH
• polymerázová řetězová reakce MeSH
• prospektivní studie MeSH
• sekvenční analýza DNA MeSH
• senioři MeSH
• transpozibilní elementy DNA MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• Publikační typ
• dopisy MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH