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International Journal of Medical... Dec 2012Clinicians are generally familiar with Acinetobacter baumannii as an aetiological agent of serious nosocomial infections in intensive care units. Other Acinetobacter...
Clinicians are generally familiar with Acinetobacter baumannii as an aetiological agent of serious nosocomial infections in intensive care units. Other Acinetobacter species can also be responsible for life-threatening sepsis. Here, we report about a bacteraemia caused by Acinetobacter parvus, community-acquired, identified with a 16S rRNA gene sequence analysis and the MALDI-TOF mass spectrometry system.
Topics: Acinetobacter; Acinetobacter Infections; Aged, 80 and over; Bacteremia; Community-Acquired Infections; DNA, Bacterial; DNA, Ribosomal; Humans; Male; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 23182682
DOI: 10.1016/j.ijmm.2012.10.002 -
International Journal of Systematic and... Sep 2003The taxonomic status of seven glucose-non-acidifying, non-proteolytic Acinetobacter strains characterized by forming small colonies on agar media was studied. With one...
The taxonomic status of seven glucose-non-acidifying, non-proteolytic Acinetobacter strains characterized by forming small colonies on agar media was studied. With one exception, all strains were from human specimens. They could be distinguished from all described Acinetobacter (genomic) species by their ability to grow on ethanol and acetate as sole sources of carbon but not on 22 other substrates tested including DL-lactate or DL-4-aminobutyrate. DNA-DNA hybridization studies, 16S rRNA gene sequence analysis, amplified rDNA restriction analysis and DNA polymorphism analysis by AFLP showed that these strains represent a hitherto unknown species of the genus Acinetobacter, for which the name Acinetobacter parvus (type strain LMG 21765(T)=LUH 4616(T)=NIPH 384(T)=CCM 7030(T)) is proposed.
Topics: Acinetobacter; Animals; DNA, Bacterial; DNA, Ribosomal; Dogs; Humans; Molecular Sequence Data; Phenotype; Phylogeny; RNA, Bacterial; RNA, Ribosomal, 16S
PubMed: 13130049
DOI: 10.1099/ijs.0.02631-0 -
Biotechnology For Biofuels 2017-acetyl-β-d-glucosamine (GlcNAc) is extensively used as an important bio-agent and a functional food additive. The traditional chemical process for GlcNAc production...
BACKGROUND
-acetyl-β-d-glucosamine (GlcNAc) is extensively used as an important bio-agent and a functional food additive. The traditional chemical process for GlcNAc production has some problems such as high production cost, low yield, and acidic pollution. Therefore, to discover a novel chitinase that is suitable for bioconversion of chitin to GlcNAc would be of great value.
RESULTS
Here, we describe the complete isolation and functional characterization of a novel exo-chitinase from HANDI 309 for the conversion of chitin. The identified exo-chitinase mainly produced -acetyl-d-glucosamine, using chitin as a substrate by submerged fermentation. The HANDI 309 biofuels producing exo-chitinase were characterized by TLC, and was further validated and quantified by HPLC. Furthermore, the optimal temperature and pH for the exo-chitinase activity was obtained in the culture conditions of 30 °C and 7.0, respectively. The maximum growth of the stationary phase was reached in 24 h after incubation. These results suggest that HANDI 309 biofuels producing exo-chitinases may have great potential in chitin to -acetyl-d-glucosamine conversion.
CONCLUSIONS
The excellent thermostability and hydrolytic properties may give the exo-chitinase great potential in chitin to GlcNAc conversion in industry. This is the first report that HANDI 309 is a novel bacterial strain that has the ability to produce an enormous amount of exo-chitinase-producing bio-agents in a short time on an industrial scale without any pretreatment, as well as being potentially valuable in the food and pharmaceutical industries.
PubMed: 28293289
DOI: 10.1186/s13068-017-0740-1 -
Genome Announcements Oct 2015Here, we report three genome sequences of bacteria isolated from murine proximal colonic tissue and identified as Acinetobacter parvus CM11, Acinetobacter radioresistens...
Draft Genome Sequences of Acinetobacter parvus CM11, Acinetobacter radioresistens CM38, and Stenotrophomonas maltophilia BR12, Isolated from Murine Proximal Colonic Tissue.
Here, we report three genome sequences of bacteria isolated from murine proximal colonic tissue and identified as Acinetobacter parvus CM11, Acinetobacter radioresistens CM38, and Stenotrophomonas maltophilia BR12.
PubMed: 26472823
DOI: 10.1128/genomeA.01089-15 -
Diagnostic Microbiology and Infectious... Oct 2012Acinetobacter species isolates from a range of environments, including soil, were investigated. We determined 16S rRNA and rpoB gene sequences for species identification...
Acinetobacter species isolates from a range of environments, including soil, were investigated. We determined 16S rRNA and rpoB gene sequences for species identification and performed tests of antimicrobial resistance susceptibility. Twenty-nine of the isolates (8 from soil and 21 from life environment) belonged to the genus Acinetobacter. Fourteen Acinetobacter species were identified among 29 isolates: 4 A. baumannii, 3 A. calcoaceticus, 1 A. nosocomialis, 2 A. pittii, and 2 Acinetobacter gen. sp. 'close to 13TU' as A. calcoaceticus-baumannii complex. Three Acinetobacter species isolates were identified as novel species candidates. Three Acinetobacter species isolates were resistant to imipenem: 1 A. parvus and 2 novel species candidates of Acinetobacter. Eight isolates showed resistance to colistin: all Acinetobacter gen. sp. 'close to 13TU' (2 isolates) and A. parvus isolates (3 isolates) were resistant to colistin. Although the genotypes of A. baumannii isolates from various natural environments were different from those of clinical isolates, the presence of clinically important and antimicrobial resistant Acinetobacter species in the natural environment may represent a threat to public health.
Topics: Acinetobacter; Anti-Bacterial Agents; DNA, Bacterial; DNA, Ribosomal; DNA-Directed RNA Polymerases; Drug Resistance, Bacterial; Environmental Microbiology; Humans; Microbial Sensitivity Tests; Molecular Typing; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 22902160
DOI: 10.1016/j.diagmicrobio.2012.06.023 -
MBio Oct 2014The amikacin resistance gene aphA6 was first detected in the nosocomial pathogen Acinetobacter baumannii and subsequently in other genera. Analysis of 133 whole-genome...
The amikacin resistance gene aphA6 was first detected in the nosocomial pathogen Acinetobacter baumannii and subsequently in other genera. Analysis of 133 whole-genome sequences covering the taxonomic diversity of Acinetobacter spp. detected aphA6 in the chromosome of 2 isolates of A. guillouiae, which is an environmental species, 1 of 8 A. parvus isolates, and 5 of 34 A. baumannii isolates. The gene was also present in 29 out of 36 A. guillouiae isolates screened by PCR, indicating that it is ancestral to this species. The Pnative promoter for aphA6 in A. guillouiae and A. parvus was replaced in A. baumannii by PaphA6, which was generated by use of the insertion sequence ISAba125, which brought a -35 sequence. Study of promoter strength in Escherichia coli and A. baumannii indicated that PaphA6 was four times more potent than Pnative. There was a good correlation between aminoglycoside MICs and aphA6 transcription in A. guillouiae isolates that remained susceptible to amikacin. The marked topology differences of the phylogenetic trees of aphA6 and of the hosts strongly support its recent direct transfer within Acinetobacter spp. and also to evolutionarily remote bacterial genera. Concomitant expression of aphA6 must have occurred because, contrary to the donors, it can confer resistance to the new hosts. Mobilization and expression of aphA6 via composite transposons and the upstream IS-generating hybrid PaphA6, followed by conjugation, seems the most plausible mechanism. This is in agreement with the observation that, in the recipients, aphA6 is carried by conjugative plasmids and flanked by IS that are common in Acinetobacter spp. Our data indicate that resistance genes can also be found in susceptible environmental bacteria. Importance: We speculated that the aphA6 gene for an enzyme that confers resistance to amikacin, the most active aminoglycoside for the treatment of nosocomial infections due to Acinetobacter spp., originated in this genus before disseminating to phylogenetically distant genera pathogenic for humans. Using a combination of whole-genome sequencing of a collection of Acinetobacter spp. covering the breadth of the known taxonomic diversity of the genus, gene cloning, detailed promoter analysis, study of heterologous gene expression, and comparative analysis of the phylogenetic trees of aphA6 and of the bacterial hosts, we found that aphA6 originated in Acinetobacter guillouiae, an amikacin-susceptible environmental species. The gene conferred, upon mobilization, high-level resistance to the new hosts. This work stresses that nonpathogenic bacteria can act as reservoirs of resistance determinants, and it provides an example of the use of a genomic library to study the origin and dissemination of an antibiotic resistance gene to human pathogens.
Topics: Acinetobacter; Amino Acid Sequence; Aminoglycosides; Anti-Bacterial Agents; Base Sequence; Cluster Analysis; Conjugation, Genetic; Drug Resistance, Bacterial; Environmental Microbiology; Escherichia coli; Evolution, Molecular; Gene Transfer, Horizontal; Interspersed Repetitive Sequences; Kanamycin Kinase; Microbial Sensitivity Tests; Molecular Sequence Data; Phylogeny; Promoter Regions, Genetic; Sequence Homology
PubMed: 25336457
DOI: 10.1128/mBio.01972-14 -
International Journal of Systematic and... Dec 2012The taxonomic position of a Gram-negative, non-motile, oxidase negative and catalase positive strain, A648(T), isolated from a hexachlorocyclohexane (HCH) dump site...
The taxonomic position of a Gram-negative, non-motile, oxidase negative and catalase positive strain, A648(T), isolated from a hexachlorocyclohexane (HCH) dump site located in Lucknow, India, was ascertained by using a polyphasic approach. A comparative analysis of a partial sequence of the rpoB gene and the 16S rRNA gene sequence revealed that strain A648(T) belonged to the genus Acinetobacter. DNA-DNA relatedness values between strain A648(T) and other closely related members (16S rRNA gene sequence similarity greater than 97%), namely Acinetobacter radioresistens DSM 6976(T), A. venetianus ATCC 31012(T), A. baumannii LMG 1041(T), A. parvus LMG 21765(T) A. junii LMG 998(T) and A. soli JCM 15062(T), were found to be less than 8%. The major cellular fatty acids of strain A648(T) were 18:1ω9c (19.6%), summed feature 3 (15.9%), 16:0 (10.6%) and 12:0 (6.4%). The DNA G+C content was 40.4 mol%. The polar lipid profile of strain A648(T) indicated the presence of diphosphatidylglycerol, phosphatidylethanolamine, followed by phosphatidylglycerol and phosphatidylcholine. The predominant polyamine of strain A648(T) was 1,3-diaminopropane and moderate amounts of putrescine, spermidine and spermine were also detected. The respiratory quinone consisted of ubiquinone with nine isoprene units (Q-9). On the basis of DNA-DNA hybridization, phenotypic characteristics and chemotaxonomic and phylogenetic comparisons with other members of the genus Acinetobacter, strain A648(T) is found to be a novel species of the genus Acinetobacter, for which the name Acinetobacter indicus sp. nov. is proposed. The type strain is A648(T) ( = DSM 25388(T) = CCM 7832(T)).
Topics: Acinetobacter; Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Hexachlorocyclohexane; India; Molecular Sequence Data; Nucleic Acid Hybridization; Phylogeny; Polyamines; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology; Soil Pollutants; Ubiquinone
PubMed: 22247213
DOI: 10.1099/ijs.0.037721-0 -
Antimicrobial Agents and Chemotherapy 2014Whole-genome sequencing of a collection of 103 Acinetobacter strains belonging to 22 validly named species and another 16 putative species allowed detection of genes for...
Whole-genome sequencing of a collection of 103 Acinetobacter strains belonging to 22 validly named species and another 16 putative species allowed detection of genes for 50 new class D β-lactamases and 65 new Acinetobacter-derived cephalosporinases (ADC). All oxacillinases (OXA) contained the three typical motifs of class D β-lactamases, STFK, (F/Y)GN, and K(S/T)G. The phylogenetic tree drawn from the OXA sequences led to an increase in the number of OXA groups from 7 to 18. The topologies of the OXA and RpoB phylogenetic trees were similar, supporting the ancient acquisition of blaOXA genes by Acinetobacter species. The class D β-lactamase genes appeared to be intrinsic to several species, such as Acinetobacter baumannii, Acinetobacter pittii, Acinetobacter calcoaceticus, and Acinetobacter lwoffii. Neither blaOXA-40/143- nor blaOXA-58-like genes were detected, and their origin remains therefore unknown. The phylogenetic tree analysis based on the alignment of the sequences deduced from blaADC revealed five main clusters, one containing ADC belonging to species closely related to A. baumannii and the others composed of cephalosporinases from the remaining species. No indication of blaOXA or blaADC transfer was observed between distantly related species, except for blaOXA-279, possibly transferred from Acinetobacter genomic species 6 to Acinetobacter parvus. Analysis of β-lactam susceptibility of seven strains harboring new oxacillinases and cloning of the corresponding genes in Escherichia coli and in a susceptible A. baumannii strain indicated very weak hydrolysis of carbapenems. Overall, this study reveals a large pool of β-lactamases in different Acinetobacter spp., potentially transferable to pathogenic strains of the genus.
Topics: Acinetobacter; Amino Acid Motifs; Anti-Bacterial Agents; Cephalosporinase; Escherichia coli; Gene Expression; Molecular Sequence Data; Phylogeny; Plasmids; Recombinant Proteins; Sequence Alignment; beta-Lactams
PubMed: 24277043
DOI: 10.1128/AAC.01261-13 -
Journal of Microbiological Methods Nov 2018A set of 204 taxonomically well-defined strains belonging to 17 Acinetobacter spp., including 11 recently described species (A. albensis, A. bohemicus, A....
A set of 204 taxonomically well-defined strains belonging to 17 Acinetobacter spp., including 11 recently described species (A. albensis, A. bohemicus, A. colistiniresistens, A. courvalinii. A. dispersus, A. gandensis, A. modestus, A. proteolyticus, A. seifertii, A. variabilis, and A. vivianii) and six species of the so-called haemolytic clade (A. beijerinckii, A. gyllenbergii, A. haemolyticus, A. junii, A. parvus, and A. venetianus), were subjected to MALDI-TOF mass spectrometric profiling. The identification outputs were evaluated using the current version (8.0.0.0) of the commercially available Bruker Daltonics, Biotyper database, which does not contain reference entries for six of the species tested. Up to 29% of the strains were falsely identified as different Acinetobacter spp. present in the Biotyper database, resulting mostly from the close phylogenetic relationship of species of the haemolytic clade. To obtain more reliable identification, extending the commercial database showed only partial improvement, while the use of an alternative MALDI matrix solution (strongly acidified ferulic acid) allowed correct identification of nearly all problematic strains.
Topics: Acinetobacter; Acinetobacter Infections; Bacterial Typing Techniques; Databases, Genetic; Genes, Bacterial; Limit of Detection; Phylogeny; RNA, Ribosomal, 16S; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 30332615
DOI: 10.1016/j.mimet.2018.10.009 -
Journal of the American Society For... Jul 2018Currently, the capability of identification for Acinetobacter species using MALDI-TOF MS still remains unclear in clinical laboratories due to certain elusory phenomena....
Insight into Identification of Acinetobacter Species by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) in the Clinical Laboratory.
Currently, the capability of identification for Acinetobacter species using MALDI-TOF MS still remains unclear in clinical laboratories due to certain elusory phenomena. Thus, we conducted this research to evaluate this technique and reveal the causes of misidentification. Briefly, a total of 788 Acinetobacter strains were collected and confirmed at the species level by 16S rDNA and rpoB sequencing, and subsequently compared to the identification by MALDI-TOF MS using direct smear and bacterial extraction pretreatments. Cluster analysis was performed based on the mass spectra and 16S rDNA to reflect the diversity among different species. Eventually, 19 Acinetobacter species were confirmed, including 6 species unavailable in Biotyper 3.0 database. Another novel species was observed, temporarily named A. corallinus. The accuracy of identification for Acinetobacter species using MALDI-TOF MS was 97.08% (765/788), regardless of which pretreatment was applied. The misidentification only occurred on 3 A. parvus strains and 20 strains of species unavailable in the database. The proportions of strains with identification score ≥ 2.000 using direct smear and bacterial extraction pretreatments were 86.04% (678/788) and 95.43% (752/788), χ = 41.336, P < 0.001. The species similar in 16 rDNA were discriminative from the mass spectra, such as A. baumannii & A. junii, A. pittii & A. calcoaceticus, and A. nosocomialis & A. seifertii. Therefore, using MALDI-TOF MS to identify Acinetobacter strains isolated from clinical samples was deemed reliable. Misidentification occurred occasionally due to the insufficiency of the database rather than sample extraction failure. We suggest gene sequencing should be performed when the identification score is under 2.000 even when using bacterial extraction pretreatment. Graphical Abstract ᅟ.
Topics: Acinetobacter; Acinetobacter Infections; Bacterial Typing Techniques; Cluster Analysis; Databases, Factual; Humans; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 29633221
DOI: 10.1007/s13361-018-1911-4