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PubMed2006

[Does pre-incubation period affect detection of Pseudomonas aeruginosa and Acinetobacter baumannii species with automatized BACTEC 9120 blood culture system?].

In this study, the effect of the pre-incubation period on detection of non-fermentative species in blood culture system was investigated. Different concentrations of Pseudomonas aeruginosa and Acinetobacter strains were inoculated into BACTEC-9120 plus+Aerobic/F bottles and incubated for 0, 4, 8, 16 hours at 36 dgerees C and then were loaded to the system. Both P. aeruginosa and A.baumannii strains yielded positive signals within 24 hours after loading. In all preincubation periods, as the concentration of P. aeruginosa strains decreased, the detection time was increased. The higher the concentration of A.baumannii strains, is the longer the signalling time as the pre-incubation period is increased, whereas the lower the concentration of A. baumannii strains, is the shorter the signalling time as the preincubation period is increased. Our study indicated that the BACTEC-9120 blood culture system determined non-fermentative bacteria after a pre-incubation time of 16 hours.

Acinetobacter baumannii↗
PubMed1991

Fatal septicaemia with Selenomonas sputigena and Acinetobacter calcoaceticus. A case report.

A 38-year-old man with a history of alcohol abuse developed rapidly fulminating septicaemia and died. Selenomonas sputigena and Acinetobacter calcoaceticus were isolated from a blood culture. Selenomonas sputigena is a motile anaerobic gram-negative rod rarely associated with systemic disease. Difficulties in isolation and taxonomic identification are discussed.

Acinetobacter↗
PubMed1991

Cellular fatty acid composition of Acinetobacter strains.

The cellular fatty acids of the different biotypes of Acinetobacter calcoaceticus were determined by high resolution gas-liquid chromatography. While all strains exhibited, qualitatively, similar fatty acid compositions, quantitative differences were observed in strains belonging to defined phenotypic subgroups which can be used for differentiation.

Acinetobacter↗
PubMed1990

[Clinical importance of bacteremias caused by Acinetobacter calcoaceticus].

Clinical data from patients with Acinetobacter calcoaceticus bacteremia observed during a period of 10 years were retrospectively reviewed. These bacteremias represent the 0.66% of the total number of positive blood cultures observed during the same period of time. The type anitratus was the most common (79.4%) although there were no significant differences in epidemiology, sensitivity, or clinical significance between both types. Only in 55.8% of the cases bacteremia was considered of clinical relevance. Multiple intravenous catheters represented the most important risk factor for bacteremia and site of infection origin (42%). Mortality in this series was about 30% of the cases. Contributions to the high mortality rate were the impossibility to establish an appropriate antimicrobial treatment in most of the cases and the existence of severe underlying diseases. The presence of immunosuppressive therapy or the existence of polymicrobial sepsis did not alter the prognosis. We conclude that once the presence of a blood culture positive to A. calcoaceticus is detected, antimicrobial treatment should be immediately established and investigation on the origin sites should be directed to the existing intravascular catheters.

Acinetobacter Infections↗
PubMed1990

Removal of lead from aqueous solution by Acinetobacter calcoaceticus.

A bacterial strain tolerant to the presence of 400 ppm lead was isolated from digested sewage sludge. The organism was identified as Acinetobacter calcoaceticus var: anitraus (98% confidence). Both viable and formalin-inactivated bacterial cells could remove Pb from an aqueous solution. The Pb-binding ability of inactivated cells was compared with that of a commercial ion-exchange resin. Amberlite IR-120. The metal-binding ability of A. calcoaceticus followed the sequence Pb greater than or equal to Cu greater than or equal to Cr greater than or equal to (Cd, Ni, and Zn) greater than or equal to Co. The ability of the inactivated cells to remove Pb was pH sensitive, and the adsorption process was slightly affected at high temperature (70 degrees C). The adsorption and desorption process worked equally well with A. calcoaceticus embedded in a polyacrylamide gel matrix.

Acinetobacter↗
PubMed1979

NADH and NADPH-viologen reductases from Acinetobacter calcoaceticus.

Three pyridine nucleotide-dependent diaphorases have been isolated from Acinetobacter calcoaceticus cells and partially characterized. Two of them, with molecular weights of 165,000 and 57,000, utilize NADPH as electron donor whereas the third one (MW = 57,000) is specific for NADH. Oxidized viologen dyes, flavin nucleotides, dichlorophenol indophenol and ferricyanide can act with efficiency as acceptors in the reaction mediated by these diaphorases. The diaphorase activities have been characterized kinetically, and the effect of different inhibitors and cofactors has been also studied. The diaphorases seem to be subjected to metabolic control by oxidation and reduction.

Acinetobacter↗
PubMed1990

Evidence of protein-tyrosine kinase activity in the bacterium Acinetobacter calcoaceticus.

Protein phosphorylation was investigated in the bacterium Acinetobacter calcoaceticus both in vivo and in vitro. In cells grown with [32P]orthophosphate, several radioactive phosphoproteins were detected by gel electrophoresis and autoradiography. These proteins were shown to contain phosphoserine, phosphothreonine, and a relatively large proportion of phosphotyrosine residues. Incubation of cellular extracts with [gamma-32P] ATP also resulted in the phosphorylation of several proteins. At least four of them, namely an 81-kDa protein, were modified at tyrosine. No protein labeling occurred when extracts were incubated with [gamma-32P] ATP or [14C]ATP. Moreover, phosphoproteins were insensitive to snake venom phosphodiesterase. All together these results indicate that A. calcoaceticus harbors different protein kinases including a protein-tyrosine kinase activity. Further analysis of this activity showed that it has little, if any, functional similarity with eukaryotic protein-tyrosine kinases.

Acinetobacter↗
PubMed1990

[Degradation of acetonitrile by Acinetobacter sp. 51-2].

A strain of Acinetobacter sp. 51-2 was capable of degrading acetonitrile and utilizing various nitrile compounds, such as propionitrile, butyronitrile, acrylonitrile and so on. The ability and speed of degrading acetonitrile were quite strong and fast. Strain 51-2 could degrade 25 g/L acetonitrile in 48 h by adapted cells. The efficiency of degrading acetonitrile was closely related to the conditions of culturing bacterial cells. The reaction temperature and present metals appeared to have a little effect on degradation of acetonitrile.

Acetonitriles↗
PubMed1989

Purification of cytochrome P-450 from n-hexadecane-grown Acinetobacter calcoaceticus.

A convenient procedure for the purification of cytochrome P-450 from an n-alkane-assimilating strain of the bacterial species Acinetobacter calcoaceticus has been elaborated. The cytochrome P-450 of n-hexadecane-grown cells was found to be distributed in cell-free extracts among particulate and soluble subcellular fractions. For isolation, cytochrome P-450 was extracted from particulate fractions by addition of Triton X-100 to the buffer. Subsequently, purification to an apparently homogeneous state was achieved by chromatography on DEAE-cellulose, Sepharose CL-6B and hydroxylapatite cellulose. A Mr of 52,000, an isoelectric point of 4.7 and the amino acid composition were determined. The Soret bands of absolute absorption spectra showed maxima at 417 nm for the oxidized form, at 408 nm for the reduced form and at 448 nm for the carbon monoxide compound of the reduced cytochrome. Difference spectra with octylamine showed maxima at 432 nm and minima at 410 nm indicating the predominance of the low-spin state. Conversion to the high-spin state could not be obtained. The isolated cytochrome P-450 was stable in the presence of Triton X-100 under neutral pH conditions. Removal of the detergent or change of the pH to values higher than 8.0 or lower than 6.0 resulted in the destruction of the cytochrome P-450.

Acinetobacter↗
PubMed1989

[A membrane-bound alanine aminopeptidase from Acinetobacter calcoaceticus. 1. Isolation and purification of the enzyme].

The alanine aminopeptidase of Acinetobacter calcoaceticus was found to be bound to the inner membranes only. The enzyme was solubilized by Triton X-100 and purified approximately 480-fold by gel filtration and affinity chromatography on alanine methyl ketone-AH-Sepharose 4B. The purified alanine aminopeptidase has a molecular mass of 212 kDa, estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme selectively catalyses the hydrolysis of N-terminal alanine residues of peptides. The enzyme is inhibited by p-hydroxy-mercuribenzoate, 1,10-phenanthroline, and puromycin, but was activated by CO2(+)-ions.

Acinetobacter↗
PubMed1989

[Enterobacter, Serratia, Acinetobacter or Pseudomonas septicemias].

During 1985 and 1986, 48 bacteremias due to Enterobacter spp, Acinetobacter spp, Serratia spp or Pseudomonas spp were collected by the SES Group. The mortality rate of those infections due to multiresistant organisms appeared high (27.9%). Among all factors influencing the prognosis, the following, age over 75 years, hospital-acquired infections, occurrence of shock and single antimicrobial therapy, are those associated with a high fatality rate. Given that clinical signs are not specific, nosocomial bacteremias should be treated by antimicrobial agents having wide spectrum, rapid onset of action and most often in combination.

Acinetobacter Infections↗
PubMed1989

[Identification and localization of exopeptidase activities bound to membranes of Acinetobacter calcoaceticus].

After gel filtration the supernatant of Triton X-100 treated membrane sediments of Acinetobacter calcoaceticus shows activities for alanyl aminopeptidase, leucyl aminopeptidase, glutamyl aminopeptidase, prolyl aminopeptidase, aminopeptidase My, gamma-glutamyl arylamidase, dipeptidylpeptidase IV and prolyl carboxypeptidase. The intracellular localization of the enzymes was analyzed by sucrose density gradient centrifugation of the DNase/RNase pretreated membrane sediments. Most of the exopeptidases are located in the inner membrane fractions (band L). Only gamma-glutamyl arylamidase is located with its main activity in the cytoplasmic membrane (band M). Only small exopeptidase activities could be found in the outer membrane (band H).

Acinetobacter↗
PubMed1989

[In vitro effect of antibiotics against hospital strains of Acinetobacter baumanii].

A total of 142 Acinetobacter baumanii strains isolated from hospital patients were biotyped according to the scheme of Bouvet and Grimont. Most of the strains belonged to biotype 9 and were highly resistant to antibiotics including cephalosporins and amikacin. Imipenem and ticarcillin were the only drugs having a bactericidal activity against A. baumanii. The combination imipenem-netilmicin and ticarcillin-netilmicin were more rapidly bactericidal than imipenem or ticarcillin alone. No resistant strain to imipenem was isolated.

Acinetobacter↗
PubMed1988

Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase II from Acinetobacter calcoaceticus. Substrate specificities and inhibition studies.

The apparent Km and maximum velocity values of benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase II from Acinetobacter calcoaceticus were determined for a range of alcohols and aldehydes and the corresponding turnover numbers and specificity constants were calculated. Benzyl alcohol was the most effective alcohol substrate for benzyl alcohol dehydrogenase. Perillyl alcohol was the second most effective substrate, and was the only non-aromatic alcohol oxidized. The other substrates of benzyl alcohol dehydrogenase were all aromatic in nature, with para-substituted derivatives of benzyl alcohol being better substrates than other derivatives. Coniferyl alcohol and cinnamyl alcohol were also substrates. Benzaldehyde was much the most effective substrate for benzaldehyde dehydrogenase II. Benzaldehydes with a single small substituent group in the meta or para position were better substrates than any other benzaldehyde derivatives. Benzaldehyde dehydrogenase II could also oxidize the aliphatic aldehydes hexan-1-al and octan-1-al, although poorly. Benzaldehyde dehydrogenase II was substrate-inhibited by benzaldehyde when the assay concentration exceeded approx. 10 microM. Benzaldehyde dehydrogenase II, but not benzyl alcohol dehydrogenase, exhibited esterase activity with 4-nitrophenyl acetate as substrate. Both benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase II were inhibited by the thiol-blocking reagents iodoacetate, iodoacetamide, 4-chloromercuribenzoate and N-ethylmaleimide. Benzyl alcohol or benzaldehyde respectively protected against these inhibitions. NAD+ also gave some protection. Neither benzyl alcohol dehydrogenase nor benzaldehyde dehydrogenase II was inhibited by the metal-ion-chelating agents EDTA, 2,2'-bipyridyl, pyrazole or 2-phenanthroline. Neither enzyme was inhibited by a range of plausible metabolic inhibitors such as mandelate, phenylglyoxylate, benzoate, succinate, acetyl-CoA, ATP or ADP. Benzaldehyde dehydrogenase II was sensitive to inhibition by several aromatic aldehydes; in particular, ortho-substituted benzaldehydes such as 2-bromo-, 2-chloro- and 2-fluoro-benzaldehydes were potent inhibitors of the enzyme.

Acinetobacter↗
PubMed1988

Preliminary crystal structure of Acinetobacter glutaminasificans glutaminase-asparaginase.

The preliminary structure of a glutaminase-asparaginase from Acinetobacter glutaminasificans is reported. The structure was determined at 3.0-A resolution with a combination of phase information from multiple isomorphous replacement at 4-5-A resolution and phase improvement and extension by two density modification techniques. The electron density map was fitted by a polypeptide chain that was initially polyalanine. This was subsequently replaced by a polypeptide with an amino acid sequence in agreement with the sizes and shapes of the side chain electron densities. The crystallographic R factor is 0.300 following restrained least squares refinement with data to 2.9-A resolution. The A. glutaminasificans glutaminase-asparaginase subunit folds into two domains: the aminoterminal domain contains a five-stranded beta sheet surrounded by five alpha helices, while the carboxyl-terminal domain contains three alpha helices and less regular structure. The connectivity is not fully determined at present, due in part to the lack of a complete amino acid sequence. The A. glutaminasificans glutaminase-asparaginase structure has been used successfully to determine the relative orientations of the molecules in crystals of Pseudomonas 7A glutaminase-asparaginase, in crystals of Vibrio succinogenes asparaginase, and in a new crystal form of Escherichia coli asparaginase (space group 1222, one subunit per asymmetric unit).

Acinetobacter↗
PubMed1987

[Evaluation of the ATB system and the 32 GN tests for the identification and determination of the antibiotic sensitivity of Acinetobacter calcoaceticus var. anitratum. Comparison with the reference dilution method in a gel medium].

The authors determined the susceptibility to 24 antibiotics of 95 strains of Acinetobacter calcoaceticus variety anitratum with the automated API ATB System in comparison with the agar dilution method for MIC measurement. The strains have been identified with API 32 GN (automated system) and API NE. There was a good agreement between the two sets of identification results. In susceptibility tests the discrepancies ranged from 0.86% to 3% with a mean value of 1.8%. The overall agreement was 95% between the two methods. This study allowed the authors to define susceptibility phenotypes to the three major antibiotic classes: beta-lactams, aminoglycosides and quinolones. The use of 32 GN tests and ATB in the automated system seems very useful, especially in epidemiologic studies in order to analyse numerous data in a short time.

Acinetobacter↗
PubMed1988

Structures of amidohydrolases. Amino acid sequence of a glutaminase-asparaginase from Acinetobacter glutaminasificans and preliminary crystallographic data for an asparaginase from Erwinia chrysanthemi.

The complete amino acid sequence of a glutaminase-asparaginase from Acinetobacter glutaminasificans, for which a preliminary tertiary structure is available from crystallographic analysis, has been determined by automated Edman degradation of fragments produced by chemical and proteolytic cleavages. The protein consists of 331 amino acid residues and has a molecular weight of 35,500. The pattern of hydrophilic and hydrophobic regions is typical of a globular protein. A new crystal form of an Erwinia chrysanthemi 1125 asparaginase is reported. The space group is monoclinic C2, with unit cell parameters of: a = 107.8, b = 91.7, c = 129.2 A and beta = 91.7 degrees. A Vm of 2.25 A3/dalton was calculated for one tetramer of 35,100-dalton subunits per asymmetric unit. X-ray intensity data have been obtained to 2.2 A resolution. The point group symmetry of the Er. chrysanthemi tetramer is 222 from self-rotation function calculations. The relative orientations of an A. glutaminasificans glutaminase-asparaginase model and the Er. chrysanthemi asparaginase tetramer have been determined with the cross-rotation function, and translation function calculations have revealed a plausible location for the asparaginase tetramer in the crystal.

Acinetobacter↗