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1.
BMC Biotechnol ; 20(1): 39, 2020 07 25.
Article En | MEDLINE | ID: mdl-32711499

BACKGROUND: With the high demand for diesel across the world, environmental decontamination from its improper usage, storage and accidental spills becomes necessary. One highly environmentally friendly and cost-effective decontamination method is to utilize diesel-degrading microbes as a means for bioremediation. Here, we present a newly isolated and identified strain of Acinetobacter calcoaceticus ('CA16') as a candidate for the bioremediation of diesel-contaminated areas. RESULTS: Acinetobacter calcoaceticus CA16 was able to survive and grow in minimal medium with diesel as the only source of carbon. We determined through metabolomics that A. calcoaceticus CA16 appears to be efficient at diesel degradation. Specifically, CA16 is able to degrade 82 to 92% of aliphatic alkane hydrocarbons (CnHn + 2; where n = 12-18) in 28 days. Several diesel-degrading genes (such as alkM and xcpR) that are present in other microbes were also found to be activated in CA16. CONCLUSIONS: The results presented here suggest that Acinetobacter strain CA16 has good potential in the bioremediation of diesel-polluted environments.


Acinetobacter calcoaceticus/genetics , Acinetobacter calcoaceticus/isolation & purification , Acinetobacter calcoaceticus/metabolism , Gasoline , Genomics , Soil Microbiology , Acinetobacter calcoaceticus/classification , Alkanes , Bacteria/classification , Bacteria/genetics , Bacteria/isolation & purification , Biodegradation, Environmental , Canada , Carbon/metabolism , Gene Expression Regulation, Bacterial , Hydrocarbons , Metabolomics , Phylogeny , Soil
2.
Molecules ; 24(1)2019 Jan 04.
Article En | MEDLINE | ID: mdl-30621147

In recent years, several efforts have been made to develop quick and low cost bacterial identification methods. Genotypic methods, despite their accuracy, are laborious and time consuming, leaving spectroscopic methods as a potential alternative. Mass and infrared spectroscopy are among the most reconnoitered techniques for this purpose, with Raman having been practically unexplored. Some species of the bacterial genus Acinetobacter are recognized as etiological agents of nosocomial infections associated with high rates of mortality and morbidity, which makes their accurate identification important. The goal of this study was to assess the ability of Raman spectroscopy to discriminate between 16 Acinetobacter species belonging to two phylogroups containing taxonomically closely related species, that is, the Acinetobacter baumannii-Acinetobacter calcoaceticus complex (six species) and haemolytic clade (10 species). Bacterial spectra were acquired without the need for any sample pre-treatment and were further analyzed with multivariate data analysis, namely partial least squares discriminant analysis (PLSDA). Species discrimination was achieved through a series of sequential PLSDA models, with the percentage of correct species assignments ranging from 72.1% to 98.7%. The obtained results suggest that Raman spectroscopy is a promising alternative for identification of Acinetobacter species.


Acinetobacter baumannii/chemistry , Acinetobacter calcoaceticus/chemistry , Cross Infection/diagnosis , Spectrum Analysis, Raman , Acinetobacter baumannii/classification , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/isolation & purification , Bacteriological Techniques , Classification , Cross Infection/microbiology , Humans
3.
Article En | MEDLINE | ID: mdl-29344351

Background: Carbapenem-nonsusceptible A. baumannii-calcoaceticus complex have emerged worldwide, but the epidemiology in Indonesian hospitals has not been studied. Methods: A prospective observational study was performed on the intensive care units (ICUs) of the national referral hospital in Jakarta-Indonesia, in 2013 and 2014. All consecutive adult patients admitted and hospitalized for >48 h in ICUs were included. Basic and clinical data at admission were recorded. Carbapenem-nonsusceptible A. baumannii-calcoaceticus complex from clinical cultures and standardized screening were included. Environmental niches and healthcare workers (HCWs) were also screened. PCR was used to detect carbapenemase genes, and Raman spectroscopy as well as multilocus sequence typing (MLST) for typing. Results: Of 412 included patients, 69 (16.7%) carried carbapenem-nonsusceptible A. baumannii-calcoaceticus complex on admission, and 89 (25.9%) became positive during ICU stay. The acquisition rate was 43 per 1000 patient-days at risk. Six isolates were cultured from environment and one from a HCW. Acquisition of carbapenem-nonsusceptible A. baumannii-calcoaceticus complex was associated with longer ICU stay (median interquartile range [IQR]: 11 days [5-18], adjusted hazard ratio [aHR]: 2.56 [99% confidence interval (CI):1.76-3.70]), but not with mortality (adjusted odds ratio: 1.59 [99%CI: 0.74-3.40] at the chosen level of significance). The blaOXA-23-like gene was detected in 292/318 (91.8%) isolates, including isolates from the environment and HCW. Typing revealed five major clusters. Sequence types (ST)195, ST208, ST218, ST642 as well as new STs were found. The dominant clone consisted of isolates from patients and environment throughout the study period. Conclusions: Carbapenem-nonsusceptible A. baumannii-calcoaceticus complex are endemic in this setting. Prevention requires source control and limiting transmission of strains. Trial registration: The study was retrospectively registered at www.trialregister.nl (No:5541). Candidate number: 23,527, NTR number: NTR5541, Date registered NTR: 22nd December 2015.


Acinetobacter Infections/epidemiology , Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/genetics , Carbapenems/pharmacology , Intensive Care Units , Molecular Epidemiology , Referral and Consultation , Acinetobacter Infections/microbiology , Acinetobacter baumannii/classification , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/drug effects , Acinetobacter calcoaceticus/isolation & purification , Adult , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , DNA, Bacterial , Drug Resistance, Bacterial/genetics , Female , Health Personnel , Humans , Indonesia/epidemiology , Male , Microbial Sensitivity Tests , Middle Aged , Multilocus Sequence Typing/methods , Polymerase Chain Reaction/methods , Prevalence , Prospective Studies , Retrospective Studies , beta-Lactamases/genetics
4.
Eur J Clin Microbiol Infect Dis ; 36(2): 219-225, 2017 Feb.
Article En | MEDLINE | ID: mdl-27714593

Acinetobacter baumannii is an important cause of multidrug-resistant hospital acquired infections in the world. Here, we investigate the presence of NDM-1 and other carbapenemases among carbapenem-resistant A. baumannii isolated between August 2010 and December 2014 from three large hospitals in Hanoi, Vietnam. We identified 23/582 isolates (4 %) (11 from hospital A, five from hospital B, and seven from hospital C) that were NDM-1 positive, and among them 18 carried additional carbapenemase genes, including seven isolates carrying NDM-1, IMP-1, and OXA-58 with high MICs for carbapenems. Genotyping indicated that NDM-1 carrying A. baumannii have expanded clonally in these hospitals. Five new STs (ST1135, ST1136, ST1137, ST1138, and ST1139) were identified. One isolate carried NDM-1 on a plasmid belonging to the N-repA replicon type; no NDM-1-positive plasmids were identified in the other isolates. We have shown the extent of the carbapenem resistance and the local clonal spread of A. baumannii carrying NDM-1 in these hospitals; coexistence of NDM-1 and IMP-1 is reported for the first time from Vietnam here, and this will further seriously limit future therapeutic options.


Acinetobacter Infections/microbiology , Acinetobacter baumannii/enzymology , Acinetobacter calcoaceticus/enzymology , Bacterial Proteins/metabolism , beta-Lactamases/metabolism , Acinetobacter Infections/epidemiology , Acinetobacter baumannii/classification , Acinetobacter baumannii/genetics , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/genetics , Acinetobacter calcoaceticus/isolation & purification , Adolescent , Adult , Aged , Carbapenems/pharmacology , Child , Child, Preschool , Female , Genotype , Hospitals , Humans , Infant , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Typing , Plasmids/analysis , Prospective Studies , Vietnam/epidemiology , Young Adult , beta-Lactam Resistance
5.
J Small Anim Pract ; 57(11): 617-625, 2016 Nov.
Article En | MEDLINE | ID: mdl-27709647

BACKGROUND: Members of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex cause severe outbreaks in humans, and are increasingly reported in animals. OBJECTIVE AND METHODS: A retrospective study, describing a severe outbreak in dogs and cats caused by a multidrug resistant member of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex in a veterinary hospital, between July 2010 and November 2012. RESULTS: The study included 19 dogs and 4 cats. Acinetobacter calcoaceticus-Acinetobacter baumannii complex bacteria were isolated from urine (9 animals), respiratory tract (11), tissues (3) and blood (1). The most common infection-associated findings included fever, purulent discharge from endotracheal tubes, hypotension, and neutropaenia. Infections led to pneumonia, urinary tract infection, cellulitis and sepsis. Infection was transmitted in the intensive care unit, where 22 of 23 animals were initially hospitalised. The mortality rate was 70% (16 of 23 animals), and was higher in cases of respiratory infection compared to other infections. Aggressive environmental cleaning and disinfection, with staff education for personal hygiene and antisepsis, sharply decreased the infection incidence. CLINICAL SIGNIFICANCE: Health care-associated outbreaks with multidrug resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex in dogs and cats are potentially highly fatal and difficult to eradicate, warranting monitoring, antiseptic techniques and judicious antibiotic use.


Acinetobacter Infections/veterinary , Acinetobacter/isolation & purification , Cat Diseases/epidemiology , Disease Outbreaks/veterinary , Dog Diseases/epidemiology , Acinetobacter/classification , Acinetobacter/drug effects , Acinetobacter Infections/epidemiology , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/drug effects , Acinetobacter calcoaceticus/isolation & purification , Animals , Cat Diseases/drug therapy , Cat Diseases/microbiology , Cats , Dog Diseases/drug therapy , Dog Diseases/microbiology , Dogs , Drug Resistance, Multiple, Bacterial , Female , Hospitals, Animal , Israel/epidemiology , Male , Retrospective Studies
6.
Microb Drug Resist ; 22(8): 655-661, 2016 Dec.
Article En | MEDLINE | ID: mdl-27082787

Acinetobacter calcoaceticus-A. baumannii complex (ACB complex) is a nosocomial pathogen. Due to its high ability to develop antibiotic resistance, it has become a problematic challenge in the modern healthcare system. The molecular and genetic mechanisms of gaining multidrug resistance in ACB complex are well known. This study focuses on providing an overview of the antibiotic resistance profiles, genetic similarities and resistotypes, and general characteristics of carbapenem-resistant ACB complex (CRACB) in Bosnia and Herzegovina (BiH). In light of the data collected in this study, together with the already known information concerning antibiotic resistance of ACB complex, we intend to further elucidate the antibiotic therapy for CRACB strain resistotypes in BiH.


Acinetobacter Infections/epidemiology , Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/genetics , Cross Infection/epidemiology , Drug Resistance, Multiple, Bacterial/genetics , beta-Lactam Resistance/genetics , Acinetobacter Infections/drug therapy , Acinetobacter Infections/microbiology , Acinetobacter baumannii/classification , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/drug effects , Acinetobacter calcoaceticus/isolation & purification , Aminoglycosides/pharmacology , Anti-Bacterial Agents/pharmacology , Bacterial Typing Techniques , Bosnia and Herzegovina/epidemiology , Carbapenems/pharmacology , Clone Cells , Cross Infection/drug therapy , Cross Infection/microbiology , Humans , Phylogeny , Trimethoprim, Sulfamethoxazole Drug Combination/pharmacology
7.
Microb Drug Resist ; 22(8): 627-637, 2016 Dec.
Article En | MEDLINE | ID: mdl-27003287

In addition to intrinsic resistance in Acinetobacter baumannii, many different types of acquired resistance mechanisms have been reported, including the presence of VIM and IMP metallo ß-lactamases and also of blaOXA-23-like and blaOXA-58-like enzymes. In the Kurdistan region of Iraq, the multiresistant A. baumannii-calcoaceticus complex is prevalent. We characterized the different mechanisms of resistance present in clinical isolates collected from different wards and different hospitals from the Kurdistan region. One hundred twenty clinical nonduplicate A. baumannii-calcoaceticus complex isolates were collected from four hospitals between January 2012 and October 2013. The identification of the isolates was confirmed by MALDI-TOF. The susceptibility to different antibiotics was determined by disk diffusion and analyzed in accordance to EUCAST guidelines. By PCR, the presence of blaOXA-51-like, blaOXA-23-like, blaOXA-24-like, and blaOXA-58-like genes was determined as well as the presence of the insertion element ISAba1. Clonal diversity was analyzed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme ApaI and, in addition, multilocus sequence typing (MLST) was performed on a selected subset of 15 isolates. All 120 A. baumannii isolates harbored blaOXA-51-like genes. One hundred one out of 110 (92%) imipenem (IMP)-resistant A. baumannii-calcoaceticus complex isolates additionally carried the blaOXA-23-like gene and four isolates (3%) were positive for blaOXA-24-like. All 101 blaOXA-23-like-positive isolates had the ISAba1 insertion sequence, 1,600 bp upstream of the blaOXA-23-like gene. The blaOXA-58-like gene was not detected in any of the 110 IMP-resistant strains. Eight different PFGE clusters were identified and distributed over the different hospitals. MLST analysis performed on a subset of 15 representative isolates revealed the presence of the international clone ST2 (Pasteur). Besides ST2 (Pasteur), also many other STs (Pasteur) were encountered such as ST136, ST94, ST623, ST792, and ST793, all carrying the blaOXA-23 gene. In clinical A. baumannii-calcoaceticus complex isolates from Kurdistan-Iraq, the blaOXA-23 gene in combination with the upstream ISAba1 insertion element is largely responsible for carbapenem resistance. Several small clusters of identical genotypes were found from patients admitted to the same ward and during overlapping time periods, suggesting transmission within the hospital. Identification of source(s) and limiting the transmission of these strains to patients needs to be prioritized.


Acinetobacter Infections/epidemiology , Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/genetics , Bacterial Proteins/genetics , Cross Infection/epidemiology , Drug Resistance, Multiple, Bacterial/genetics , Gene Expression Regulation, Bacterial , beta-Lactamases/genetics , Acinetobacter Infections/drug therapy , Acinetobacter Infections/microbiology , Acinetobacter baumannii/classification , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/drug effects , Acinetobacter calcoaceticus/isolation & purification , Adolescent , Adult , Aged , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/classification , Bacterial Proteins/metabolism , Child , Child, Preschool , Clone Cells , Cross Infection/drug therapy , Cross Infection/microbiology , Disk Diffusion Antimicrobial Tests , Electrophoresis, Gel, Pulsed-Field , Female , Humans , Imipenem/pharmacology , Iraq/epidemiology , Male , Middle Aged , Multilocus Sequence Typing , Phylogeny , Plasmids/chemistry , Plasmids/metabolism , Polymerase Chain Reaction , Prevalence , beta-Lactamases/classification , beta-Lactamases/metabolism
8.
Medicine (Baltimore) ; 95(9): e2937, 2016 Mar.
Article En | MEDLINE | ID: mdl-26945401

Clinical infections caused by Acinetobacter spp. have increasing public health concerns because of their global occurrence and ability to acquire multidrug resistance. Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex encompasses A. calcoaceticus, A. baumannii, A. pittii (formerly genomic species 3), and A nosocomial (formerly genomic species 13TU), which are predominantly responsible for clinical pathogenesis in the Acinetobacter genus. In our previous study, a putative novel species isolated from 385 non-A. baumannii spp. strains based on the rpoB gene phylogenetic tree was reported. Here, the putative novel species was identified as A. seifertii based on the whole-genome phylogenetic tree. A. seifertii was recognized as a novel member of the ACB complex and close to A. baumannii and A. nosocomials. Furthermore, we studied the characteristics of 10 A. seifertii isolates, which were distributed widely in 6 provinces in China and mainly caused infections in the elderly or children. To define the taxonomic status and characteristics, the biochemical reactions, antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequence analysis were performed. The phenotypic characteristics failed to distinguish A. serfertii from other species in the ACB complex. Most of the A. seifertii isolates were susceptible to antibiotics commonly used for nosocomial Acinetobacter spp. infections, but one isolate (strain A362) was resistant to ampicillin/sulbactam, ceftazidime and amikacin. The different patterns of MLST and PFGE suggested that the 10 isolates were not identical and lacked clonal relatedness. Our study reported for the first time the molecular epidemiological and genomic features of widely disseminated A. seifertii in China. These observations could enrich the knowledge of infections caused by non-A. baumannii and may provide a scientific basis for future clinical treatment.


Acinetobacter/isolation & purification , Acinetobacter/classification , Acinetobacter/drug effects , Acinetobacter Infections/microbiology , Acinetobacter baumannii/classification , Acinetobacter calcoaceticus/classification , Aged , Anti-Bacterial Agents/pharmacology , Child , China , Drug Resistance, Bacterial , Electrophoresis, Gel, Pulsed-Field , Humans , Molecular Epidemiology , Multilocus Sequence Typing , Phylogeny , Sequence Analysis
9.
Diagn Microbiol Infect Dis ; 83(2): 99-104, 2015 Oct.
Article En | MEDLINE | ID: mdl-26198329

Acinetobacter baumannii belongs to the Acinetobacter calcoaceticus-baumannii complex (Acb) containing 2 other pathogenic species: Acinetobacter pittii and Acinetobacter nosocomialis. Identification of these bacteria remains problematic despite the use of matrix-assisted laser ionization time-of-flight mass spectrometry (MALDI-TOF MS). Here, we enriched the SARAMIS™ database of the Vitek MS® plus mass spectrometer to improve the identification of species of the Acb complex. For each species, we incremented reference spectra. Then, a SuperSpectrum was created based on the selection of 40 specific masses. In a second step, we validated reference spectra and SuperSpectra with 100 isolates identified by rpoB gene sequencing. All the isolates were correctly identified by MALDI-TOF MS with the database we created as compared to the identifications obtained by rpoB sequencing. Our database enabled rapid and reliable identification of the pathogen species belonging to the Acb complex. Identification by MALDI-TOF MS with our database is a good alternative to molecular biology.


Acinetobacter baumannii/classification , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/isolation & purification , Bacteriological Techniques/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Acinetobacter baumannii/chemistry , Acinetobacter calcoaceticus/chemistry , Humans , Time Factors
10.
Genet Mol Res ; 14(1): 2793-8, 2015 Mar 31.
Article En | MEDLINE | ID: mdl-25867428

One of the main limitations in intensive crop production in Northwestern Mexico is the dependence on the use of phosphate fertilizer. In this study, we isolated indigenous microorganisms with phosphate solubilization capacities from mesquite (Prosopis glandulosa) present in the Mexicali valley. In total, 4 bacteria were isolated from the rhizosphere of mesquite, including ICA01, ICA02Ba, ICA03Bs, and ICA04Ma. The bacterial isolates were identified based on their phenotypic and 16S rRNA gene sequencing data to be Acinetobacter calcoaceticus. The results showed that ICA01 was the most efficient in solubilizing phosphate, followed by ICA02Ba and ICA03Bs, while ICA04Ma showed the lowest phosphate-solubilizing activity. The pH value of the culture medium decreased with bacterial growth, suggesting that these strains produce organic acids that solubilize phosphorus. These results will be useful for biotechnological studies and A. calcoaceticus may be employed for biofertilization programs in northwest Mexico.


Bacteria/genetics , Bacteria/metabolism , Phosphates/metabolism , Prosopis/microbiology , Rhizosphere , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/genetics , Acinetobacter calcoaceticus/metabolism , Bacteria/classification , Hydrogen-Ion Concentration , Mexico , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Solubility , Species Specificity
11.
Curr Microbiol ; 70(1): 75-84, 2015 Jan.
Article En | MEDLINE | ID: mdl-25194282

The pyrethroid insecticide cypermethrin is in extensive use since 1980s for insect control. However, its toxicity toward aquatic animals and humans requires its complete removal from contaminated areas that can be done using indigenous microbes through bioremediation. In this study, three bacterial strains isolated from agricultural soil and identified as Acinetobacter calcoaceticus MCm5, Brevibacillus parabrevis FCm9, and Sphingomonas sp. RCm6 were found highly efficient in degrading cypermethrin and other pyrethroids. These bacterial strains were able to degrade more than 85 % of cypermethrin (100 mg L(-1)) within 10 days. Degradation kinetics of cypermethrin (200 mg kg(-1)) in soils inoculated with isolates MCm5, FCm9, and RCm6 suggested time-dependent disappearance of cypermethrin with rate constants of 0.0406, 0.0722, and 0.0483 d(-1) following first-order rate kinetics. Enzyme assays for Carboxylesterase, 3-PBA dioxygenase, Phenol hydroxylase, and Catechol-1,2 dioxygenase showed higher activities with cypermethrin treated cell-free extracts compared to non-treated cell-free extracts. Meanwhile, SDS-PAGE analysis showed upregulation of some bands in cypermethrin-treated cells. This might suggest that cypermethrin degradation in these strains involves inducible enzymes. Besides, the isolates displayed substantial plant growth-promoting traits such as phosphate solubilization, Indole acetic acid production, and ammonia production. Implying the efficient biodegradation potential along with multiple biological properties, these isolates can be valuable candidates for the development of bioremediation strategies.


Acinetobacter calcoaceticus/metabolism , Brevibacillus/metabolism , Insecticides/metabolism , Plants/microbiology , Pyrethrins/metabolism , Sphingomonas/metabolism , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/genetics , Acinetobacter calcoaceticus/isolation & purification , Biodegradation, Environmental , Brevibacillus/classification , Brevibacillus/genetics , Brevibacillus/isolation & purification , Insecticides/chemistry , Kinetics , Molecular Sequence Data , Phylogeny , Plant Development , Pyrethrins/chemistry , Soil Microbiology , Sphingomonas/classification , Sphingomonas/genetics , Sphingomonas/isolation & purification
13.
PLoS One ; 9(8): e105390, 2014.
Article En | MEDLINE | ID: mdl-25141005

To determine whether ITS sequences in the rrn operon are suitable for identifying individual Acinetobacter Acb complex members, we analysed length and sequence differences between multiple ITS copies within the genomes of individual strains. Length differences in ITS reported previously between A. nosocomialis BCRC15417T (615 bp) and other strains (607 bp) can be explained by presence of an insertion (indel 13i/1) in the longer ITS variant. The same Indel 13i/1 was also found in ITS sequences of ten strains of A. calcoaceticus, all 639 bp long, and the 628 bp ITS of Acinetobacter strain BENAB127. Four additional indels (13i/2-13i/5) were detected in Acinetobacter strain c/t13TU 10090 ITS length variants (608, 609, 620, 621 and 630 bp). These ITS variants appear to have resulted from horizontal gene transfer involving other Acinetobacter species or in some cases unrelated bacteria. Although some ITS copies in strain c/t13TU 10090 are of the same length (620 bp) as those in Acinetobacter strains b/n1&3, A. pittii (10 strains), A. calcoaceticus and A. oleivorans (not currently acknowledged as an Acb member), their individual ITS sequences differ. Thus ITS length by itself can not by itself be used to identify Acb complex strains. A shared indel in ITS copies in two separate Acinetobacter species compromises the specificity of ITS targeted probes, as shown with the Aun-3 probe designed to target the ITS in A. pitti. The presence of indel 13i/5 in the ITS of Acinetobacter strain c/t13TU means it too responded positively to this probe. Thus, neither ITS sequencing nor the currently available ITS targeted probes can distinguish reliably between Acb member species.


Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/genetics , DNA, Ribosomal Spacer/genetics , INDEL Mutation , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 23S/genetics , Acinetobacter baumannii/classification , Acinetobacter calcoaceticus/classification , Phylogeny
14.
Int J Med Microbiol ; 304(5-6): 669-77, 2014 Jul.
Article En | MEDLINE | ID: mdl-24877727

MALDI-TOF MS is becoming the technique of choice for rapid bacterial identification at species level in routine diagnostics. However, some drawbacks concerning the identification of closely related species such as those belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii (Acb) complex lead to high rates of misidentifications. In this work we successfully developed an approach that combines MALDI-TOF MS and chemometric tools to discriminate the six Acb complex species (A. baumannii, Acinetobacter nosocomialis, Acinetobacter pittii, A. calcoaceticus, genomic species "Close to 13TU" and genomic species "Between 1 and 3"). Mass spectra of 83 taxonomically well characterized clinical strains, reflecting the breadth of currently known phenetic diversity within the Acb complex, were achieved from intact cells and cell extracts and analyzed with hierarchical cluster analysis (HCA) and partial least squares discriminant analysis (PLSDA). This combined approach lead to 100% of correct species identification using mass spectra obtained from intact cells. Moreover, it was possible to discriminate two Acb complex species (genomic species "Close to 13TU" and genomic species "Between 1 and 3") not included in the MALDI Biotyper database.


Acinetobacter Infections/diagnosis , Acinetobacter baumannii/chemistry , Acinetobacter baumannii/classification , Acinetobacter calcoaceticus/chemistry , Acinetobacter calcoaceticus/classification , Bacteriological Techniques/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Acinetobacter Infections/microbiology , Humans
15.
J Basic Microbiol ; 54(5): 457-63, 2014 May.
Article En | MEDLINE | ID: mdl-23712768

A bacterial strain D10 with strong ability of degrading chlorpyrifos was isolated from rhizosphere of chives contaminated with pesticide. It was found that it's capable of utilizing chlorpyrifos as the sole source of carbon for growth, and within the first 4 days the extent of degradation at initial concentration of 100 mg L(-1) was 60.0%. It also showed a high ability of degrading chlorpyrifos in sterilized soil, and the degradation reached up to 60.2% after 18 days. In addition, the strain D10 also showed multiple plant growth-promoting traits of phosphate solubilization, indole-3-acetic acid and siderophore production. The results indicate that the strain D10 has potential in the application of pesticide-degrading and plant growth promotion. Strain D10 was identified as Acinetobacter calcoaceticus based on its morphological, physiological-biochemical properties and the 16S rRNA sequence analysis.


Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/isolation & purification , Chlorpyrifos/metabolism , Acinetobacter calcoaceticus/genetics , Acinetobacter calcoaceticus/metabolism , Bacterial Typing Techniques , Biotransformation , Carbon/metabolism , Cluster Analysis , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Indoleacetic Acids/metabolism , Molecular Sequence Data , Phosphates/metabolism , Phylogeny , Plant Growth Regulators/metabolism , RNA, Ribosomal, 16S/genetics , Rhizosphere , Sequence Analysis, DNA , Siderophores/metabolism , Soil Microbiology
16.
Scand J Infect Dis ; 45(6): 446-52, 2013 Jun.
Article En | MEDLINE | ID: mdl-23317168

BACKGROUND: Acinetobacter baumannii-calcoaceticus complex (ABC) isolates are often multidrug-resistant, including to carbapenems. Chromogenic media can facilitate the rapid detection of Gram-negative bacteria, often with the addition of supplements to a base chromogenic medium to detect resistance. We examined various combinations of available media to detect imipenem resistance among 107 ABC clinical isolates. METHODS: CHROMagar Orientation, CHROMagar KPC, and CHROMagar Acinetobacter, by itself, with Acinetobacter supplement, with KPC supplement, or CHROMagar Acinetobacter with increasing concentrations (1, 2.5, and 5 ml/l) of a new CR102 supplement, were examined. RESULTS: Sensitivity for the detection of isolates was high (> 98%) for all formulations. Specificity was high for CHROMagar Acinetobacter with 2.5 ml/l and 5 ml/l of the CR102 supplement, at 95.3% and 97.7%, respectively, with positive predictive values of 97% and 98.5%. Negative predictive values of these 2 formulations were 100%. CONCLUSIONS: CHROMagar Acinetobacter with the addition of the CR102 supplement at 2.5 ml/l and 5ml/l is highly sensitive and specific for the detection of imipenem-resistant ABC, and may be useful for the rapid detection of imipenem-resistant ABC in clinical samples.


Acinetobacter Infections/microbiology , Acinetobacter baumannii/drug effects , Acinetobacter calcoaceticus/drug effects , Anti-Bacterial Agents/pharmacology , Bacterial Typing Techniques/methods , Imipenem/pharmacology , Acinetobacter baumannii/classification , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/isolation & purification , Culture Media , Humans , Microbial Sensitivity Tests , Predictive Value of Tests , beta-Lactam Resistance
17.
Biomed Environ Sci ; 25(6): 711-7, 2012 Dec.
Article En | MEDLINE | ID: mdl-23228842

OBJECTIVE: Gas chromatography (GC) was used to investigate the cellular fatty acid (CFA) composition of 141 Acinetobacter baumannii and 32 A. calcoaceticus isolates from different locations in China and to find chemical markers to differentiate these two closely related bacteria. METHODS: Whole cell fatty acid methyl esters (FAMEs) were obtained by saponification, methylation, and extraction for GC analysis, followed by a standardized Microbial Identification System (MIS) analysis. RESULTS: All A. baumannii and A. calcoaceticus strains contained some major fatty acids, namely, 18:1 ω9c, 16:0, Sum In Feature 3, 12:0, 17:1ω8c, 3-OH-12:0, 17:0, Sum In Feature 2, 2-OH-12:0, and 18:0 compounds. Although most of the total CFAs are similar between A. baumannii and A. calcoaceticus strains, the ratios of two pairs of CFAs, i.e., Sum In Feature 3/18:1 ω9c versus 16:0/18:1 ω9c and Sum In Feature 3/18:1 ω9c versus unknown 12.484/18:1 ω9c fatty acids, could differentiate these two closely related bacteria. A. baumannii could be easily classified into two subgroups by plotting some ratios such as Sum In Feature 3/16:0 versus 17:0 and Sum In Feature 3/2-OH-12:0 versus 17:0 fatty acids. CONCLUSION: The ratios of some CFAs could be used as chemical markers to distinguish A. baumannii from A. calcoaceticus.


Acinetobacter baumannii/classification , Acinetobacter calcoaceticus/classification , Fatty Acids/metabolism , Acinetobacter baumannii/cytology , Acinetobacter baumannii/metabolism , Acinetobacter calcoaceticus/cytology , Acinetobacter calcoaceticus/metabolism , Biomarkers/metabolism , Species Specificity
18.
J Clin Microbiol ; 50(9): 2982-6, 2012 Sep.
Article En | MEDLINE | ID: mdl-22760035

This study investigated the clinical and microbiological characteristics of patients with recurrent bacteremia caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex at a medical center. All ACB complex isolates associated with recurrent bacteremia were identified to the genomic species level using a 16S-23S rRNA gene intergenic spacer sequence-based method. Genotypes were determined by the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR and by pulsotypes generated by pulsed-field gel electrophoresis. Relapse of infection was defined as when the genotype of the recurrent isolate was identical to that of the original infecting strain. Reinfection was defined as when the genospecies or genotype of the recurrent isolate differed from that of the original isolate. From 2006 to 2008, 446 patients had ACB complex bacteremia and 25 (5.6%) had recurrent bacteremia caused by the ACB complex. Among the 25 patients, 12 (48%) had relapse of bacteremia caused by A. nosocomialis (n = 7) or A. baumannii (n = 5). Among the 13 patients with reinfection, 5 (38.5%) had reinfection caused by different genospecies of the ACB complex. Most of the patients were immunocompromised, and most of the infection foci were catheter-related bloodstream infections. The overall in-hospital mortality rate was 33.3%. A. baumannii isolates had lower antimicrobial susceptibility rates than A. nosocomialis and A. pittii isolates. In conclusion, relapse of ACB complex bacteremia can develop in immunocompromised patients, especially those with central venous catheters. Molecular methods to identify the ACB complex to the genospecies level are essential for differentiating between reinfection and relapse of bacteremia caused by the ACB complex.


Acinetobacter Infections/microbiology , Acinetobacter baumannii/isolation & purification , Acinetobacter calcoaceticus/isolation & purification , Bacteremia/microbiology , Academic Medical Centers , Acinetobacter Infections/epidemiology , Acinetobacter Infections/mortality , Acinetobacter baumannii/classification , Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/genetics , Adult , Aged , Anti-Bacterial Agents/pharmacology , Bacteremia/epidemiology , Bacteremia/mortality , Female , Genotype , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Molecular Typing , Random Amplified Polymorphic DNA Technique , Recurrence , Sequence Analysis, DNA , Survival Analysis , Taiwan/epidemiology
19.
Diagn Microbiol Infect Dis ; 73(3): 284-6, 2012 Jul.
Article En | MEDLINE | ID: mdl-22595610

During multilocus sequence analysis of Acinetobacter calcoaceticus-Acinetobacter baumannii complex, we identified the evidence of recent genetic recombination between 2 Acinetobacter species. While 3 isolates belonged to A. nosocomialis based on 16S rRNA, gyrB, fusA, gdhB, and rplB gene sequences, they showed close relationships with Acinetobacter genomic species 'close to 13TU' in rpoB, recA, cpn60, rpoD, and gltA gene trees.


Acinetobacter baumannii/classification , Acinetobacter baumannii/genetics , Acinetobacter calcoaceticus/classification , Acinetobacter calcoaceticus/genetics , DNA, Bacterial/genetics , Multilocus Sequence Typing , Recombination, Genetic , Bacterial Proteins/genetics , DNA, Bacterial/chemistry , Humans , Molecular Sequence Data , RNA, Ribosomal, 16S/genetics
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