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PubMed1988

[Nucleotide sequences of mercury resistance determinants in bacteria isolated from mercury mines: detection of a family of recombinant mercury transposons in plasmids from Acinetobacter species].

Partial nucleotide sequences were determined for mer operons located on large and small plasmids previously described in Acinetobacter spp. isolated from different mercury mines of the USSR. Inspection of the sequences shows that: 1. All Acinetobacter mer operons studied belong to a family of transposons homologous to transposons found in clinical isolates. 2. The transposons located on the small plasmids originated by recombinations between the transposons from the large plasmids and Tn501, a transposon found in a Pseudomonas hospital strain isolated in Australia. The left arm of each hybrid transposon was donated by a transposon of a large Acinetobacter plasmid and the right arm - by the Tn501.

Acinetobacter↗
PubMed1989

[Identification and determination of sensitivity to antibiotics of 31 clinical strains of Acinetobacter other than A. baumannii].

Precise identification and determination of MICs of clinical isolates of Acinetobacter identified to other species than the hospital species A. baumannii were carried out. On 260 Acinetobacter strains isolated in an hospital over a 6 months period, 31 strains (12 p. cent) were identified to species other than A. baumannii. Among these 31 strains, A. Iwoffii sensu stricto (16 strains) and A. haemolyticus (6 strains) were mostly recovered. Eight glucose oxidizing strains were identified to A. haemolyticus (6 strains), Acinetobacter genospecies 3 (2 strains), and A. Iwoffii sensu stricto (1 strain). Antibiotic susceptibilities of these strains were greater than those commonly observed with A. baumannii strains.

Acinetobacter↗
PubMed1979

Acinetobacter and E. coli lipopolysaccharide preparations comparative mitogenicity and induction in vitro of immunoglobulin synthesis in adult and neonatal pig lymphocytes.

Lipopolysaccharide (LPS) was prepared by phenol/water extraction of bacterial membranes prepared from Acinetobacter and Escherichia coli. The mitogenicity of laboratory-prepared LPS was significantly greater than that of commercial E. coli LPS for pig, sheep, calf and rat lymphocytes, assayed as [3H]-thymidine incorporation. Mouse lymphocytes responded well to commercial LPS and no greater response was obtained with other LPS preparations. A small proportion (14%) of the Acinetobacter LPS preparations was soluble in aqueous medium, the remainder comprising membraneous fragments of variable form and size. It is suggested that the insoluble presentation of LPS to cells may contribute to the improved mitogenicity compared with wholly soluble LPS. Acinetobacter LPS preparations were used to induce synthesis and secretion in vitro of immunoglobulin by adult blood lymphocytes and pre-suckled, neonatal spleen cells of the pig. IgM was the dominant class of immunoglobulin secreted. This work thus demonstrated that virgin, unprimed B cells could be induced into immunoglobulin secretion by mitogen stimulation.

Acinetobacter↗
PubMed1985

Transferable amikacin and cefamandole resistance: Pseudomonas maltophilia and Acinetobacter strains as possible reservoirs of R plasmids.

Three strains belonging to gramnegative non-fermenting rods, i.e. a Pseudomonas maltophilia strain and two strains of Acinetobacter, were tested, as representatives of different types of nosocomial strains, for transferability of their multiple drug resistance. As all of them posed difficulties in demonstrating the transferability of their resistance by conventional methods, a three-step procedure was developed that includes a transfer to rifampicin-resistant P. aeruginosa recipients, then to susceptible P. aeruginosa intermediate strains, and, finally, from these strains to rifampicin-resistant Enterobacteriaceae. In three strains studied three genetically different types of R plasmids have been demonstrated. P. maltophilia transferred Amikacin resistance, as well as resistance to other antibiotics, to P. aeruginosa and then to Enterobacteria. In contrast, an Amikacin-resistant Acinetobacter with quite identical multiple drug resistance spectrum transferred its resistance to P. aeruginosa only, but not to Enterobacteria. Finally, another Acinetobacter strain, resistant to Gentamicin but susceptible to Amikacin transferred this resistance directly to Enterobacteria (and, separately, to P. aeruginosa, too). All three strains transferred Cefamandole resistance together with other resistances. Non-fermenting rods, thus, might be a source of transmissible resistance to reserve antibiotics as Amikacin, and advanced-type Cephalosporins.

Acinetobacter↗
PubMed1984

[Bioenzymatic and lysotypic study of 200 strains of Acinetobacter calcoaceticus].

Two hundred strains of Acinetobacter calcoaceticus isolated between 1971 and 1978 at the Bichat Hospital were studied by means of a biochemical and enzymatic technique thanks to 150 tests per strain. Most strains (about 60%) were Acinetobacter calcoaceticus variety anitratus which is more frequently isolated than var. lwoffi . Three bioenzymatic groups have been statistically defined. This classification corresponds to the main lines of previous descriptions by Henriksen (1960) and those indicated in the Bergey's Manual (1974). The results of the study do not show any correlation between the clinical origin of the strains, their bioenzymatic profile and their phage-type which was determined for 60 strains. Otherwise, it was to be noted that glucose is not a basic character of this classification which is based on an average profile of strains; some tests are particularly important for the differentiation of species (amino-acids); some characteristics have been observed and have to be related to the enzymatic properties of the strains and their role in the catabolism of some carbohydrates. The results of the study might constitute a new approach of epidemiological criteria to be determined for Acinetobacter strains ( Bergogne -Bér ezin and al., 1970, 1980, Gardner and al., 1970; Glew and al., 1977).

Acinetobacter↗
PubMed1978

[Cytochrome composition of Acinetobacter calcoaceticus].

The qualitative and quantitative composition of cytochromes in intact cells of Acinetobacter calcoaceticus and in particle fractions obtained from cells following ultrasonic treatment by differential centrifugation were studied using spectrophotometric methods. Acinetobacter calcoaceticus contains cytochrome b, cytochrome o and low amounts of cytochrome d. Both the absolute content of cytochrome b and o and the relative composition do not essentially vary with the carbon source used (hexadecane, acetate, succinate, malate, yeast extract). Only bacterial cultivated on yeast extract show, under simultaneous decrease of the content of cytochrome o, an increased formation of cytochrome d. In Acinetobacter, cytochromes appear not to be immediately involved in n-alkane hydroxylation.

Acinetobacter↗
PubMed1993

Acinetobacter sepsis in neonates.

Twenty-six neonates were diagnosed to have acinetobacter sepsis during 1986-90, representing 6.5% of all cases of bacteriologically proven sepsis. Of these 19 neonates were low birth weight (LBW) 12 were small for gestational age (SGA). Nineteen neonates had early-onset sepsis. The male to female ratio was 9:17. The hematological profile was suggestive of sepsis in 17 cases. All infants had clinical evidence of multi system infection. Eleven babies died; the cases-fatality rate was 42.3%. Only 15/25 culture isolates were sensitive to gentamicin and resistance to other antibiotics was even more frequent. Acinetobacter was cultured from other sites: eye swabs, skin pustules and umbilical catheter tips. Environmental nursery surveillance cultures done during the study period yielded Acinetobacter once from a crib, but no cases of sepsis occurred around that time. The epidemiological features of this organism illustrate the value of vigilance and precautionary measures.

Acinetobacter↗
PubMed1993

[Susceptibility to antibiotics and biochemical activity of strains of Acinetobacter sp. isolated from various sources].

The study was performed on 576 Acinetobacter strains isolated from clinical material, objects from hospital, environment, soil, water and from animals. Applying API 20NE system identification was following: A. baumanii (61.1%), A. junii (19.4%), A. haemolyticus (4.3%), A. lwoffii (3.3%), A. johnsonii (0.52%) and not belonging to above genus strains (11.3%). Over 47% strains of Acinetobacter were isolated from clinical material as the only bacteria (mainly from samples received from intensive care units and surgical and urological wards). Out of 23 antibiotics and antimicrobials used for investigation of 535 strains of Acinetobacter, most active were imipenem (99%) of susceptible strains, ofloxacin and ciprofloxacin (95%) and netilmicin (88%). Multiple resistant strains were isolated more frequently from hospital environment than from other sources--these were mostly A. baumanii and A. junii.

Acinetobacter↗
PubMed1996

[Taxonomy of the genus Acinetobacter].

In the last decade the taxonomy of the genus Acinetobacter showed important changes. Since 1986 several classification studies have been published dividing progressively the genus Acinetobacter, originally believed to include a single species, A. calcoaceticus, into 19 genomospecies. The following papers paid attention to practical possibilities of identification and to clinical importance of different species and genomospecies. In the last three years, interesting data on the distribution of different Acinetobacter species in the Czech Republic and on taxonomic position of the multiresistant strains and those isolated from nosocomial outbreaks have been gathered in our laboratory.

Acinetobacter↗
PubMed1996

Changing trends in the antimicrobial susceptibility of clinical isolates of Acinetobacter baumannii.

Acinetobacter baumannii has recently emerged as an important nosocomial pathogen because of its resistance to the majority of commonly used antimicrobial agents. Therefore, the pattern of isolation of Acinetobacter baumannii in our laboratory and the in vitro susceptibilities to various antimicrobial agents were studied. One hundred and two clinical isolates of previously identified Acinetobacter calcoaceticus var. anitratus from different patients were collected from the Diagnostic Bacteriology section of the Department of Pathology, Singapore General Hospital. The strains were reclassified according to recent taxonomic changes using phenotypic tests and tested for beta-lactamase production using Cefinase disks. In vitro sensitivities to various antimicrobial agents were determined using the disk diffusion method. Of the 103 A. calcoaceticus var. anitratus species, 99 were identified as A. baumannii, 2 as A. junii and 1 as A. haemolyticus. Majority of the A. baumannii isolates were from wound sites (63.6%) and from patients in the general wards (70.7%). beta-lactamase activity was present in all these isolates. The most active agent against all A. baumannii isolates was imipenem. However, 14 of the strains were resistant to imipenem, 8 of which came from the burns ward. Two-thirds of isolates from burn patients were completely resistant to all the antimicrobial agents tested. Almost all isolates previously identified as A. calcoaceticus var. anitratus in our laboratory are A. baumannii strains. Imipenem is the most effective antimicrobial agent; however, the high rate of imipenem resistance especially among burn patients is a source of major concern.

Acinetobacter calcoaceticus↗
PubMed1996

A retrospective study of clinical characteristics of acinetobacter bacteremia.

High rates of acinetobacter bacteremia were observed in a large teaching hospital in Hong Kong. A retrospective study of 94 acinetobacter bacteremic episodes in patients in 1993-94 revealed 70 episodes of significant bacteremia. 53% of the patients were over 60 years with a male to female ratio of 1.5:1. Cases were most rare during the fourth quarter. The intensive care unit was the commonest location of acquisition of bacteremia. Most infections were hospital acquired. Intravascular catheters, urinary catheters, antibiotic therapy and respiratory tract manipulations were common risk factors. Lower respiratory tract infections and catheter-related sepsis were predominant foci of bacteremia. One-third of the patients received appropriate antibiotics within 48 hours after bacteremia onset. Mortality attributable to acinetobacter infection was 27%. Prognosis of underlying diseases, location in intensive care unit, lower respiratory tract infection as foci of infection as well as diabetes mellitus were associated with mortality.

Acinetobacter Infections↗
PubMed2006

Epidemiology of multiple Acinetobacter outbreaks in The Netherlands during the period 1999-2001.

An increase in the number of outbreaks of Acinetobacter infection was notified in The Netherlands during 1999-2001. The present study compared the outbreaks at the species and strain levels, and analysed the epidemiology and control measures at the different locations. For each institute, three representative isolates from three patients were identified to the species and strain levels by genotyping methods. A questionnaire investigated the impact of the outbreak, the control measures that were taken, and the possible effects of the measures. Seven outbreaks were associated with Acinetobacter baumannii (three outbreaks with a strain designated strain A, two outbreaks with a strain designated strain B, and one outbreak each with strains designated C and D). An additional outbreak was caused by genomic species 13TU, which is related closely to A. baumannii. Strains B and D were identified as European clones III and II, respectively. Except for two hospitals with outbreaks caused by strain A, there was no known epidemiological link between the participating hospitals. In all hospitals the outbreak occurred on one or several intensive care units, and spread to other departments was noted in two hospitals. The number of patients affected ranged from six to 66 over a period of 2-22 months. In most outbreaks, patients were the likely reservoir from which spread occurred. In all hospitals, a large panel of measures was required to bring the outbreak to an end. Extensive environmental sampling yielded numerous positive samples in most but not all hospitals.

Acinetobacter↗
PubMed2006

Pyrosequencing for rapid identification of carbapenem-hydrolysing OXA-type beta-lactamases in Acinetobacter baumannii.

Carbapenem-resistant Acinetobacter baumannii isolates producing carbapenem-hydrolysing oxacillinases are emerging worldwide. These enzymes are divided into four phylogenetic subgroups: OXA-23-like, OXA-51-like, OXA-24-like and OXA-58-like. A PCR-based approach linked to pyrosequencing analysis was developed to identify the genes for these beta-lactamases. Carbapenem-hydrolysing oxacillinases were rapidly and unambiguously identified in a collection of carbapenem-resistant clinical isolates of A. baumannii and Acinetobacter junii. Pyrosequencing may provide a rapid tool for identification of OXA variants, thus avoiding delays inherent in classical sequencing methods.

Acinetobacter↗
PubMed1997

Phosphate Release and Uptake by Pure Cultures of Acinetobacter sp.: Effect of the Volatile Fatty Acids Concentration

Phosphorus release and uptake by pure cultures of Acinetobacter strains were investigated under anaerobic and aerobic conditions respectively. Tests were performed to study the relationship between phosphorus release-storage reaction and behavior of extracellular organic substrates: acetic, propionic, and butyric acids have been used at four concentrations (50, 100, 500, and 1000 mg · L-1) in the anaerobic step of biological phosphorus removal. The results obtained depend on the strain and the volatile fatty acid (VFA) used. Phosphorus released under anaerobic condition was not always related to the amount of VFA or phosphorus consumed. Phosphorus uptake (P-uptake) in the aerobic step was found to be independent of phosphorus release rates. The best phosphorus uptake rates were obtained by Acinetobacter lwoffi ATCC21130 and Acinetobacter calcoaceticus Genoespecie SUCT-5 with butyric acid as carbon source.

Journal Article↗
PubMed1968

Isolation of Acinetobacter from soil and water.

An enrichment culture procedure for isolating members of the genus Acinetobacter from soil and water is described. It involves the use of vigorously aerated mineral media at relative low pH, supplemented with acetate or other suitable carbon source and nitrate as nitrogen source. With this method, virtually all samples of soil and water yielded representatives of this genus. Semiquantitative comparisons of the numbers of Acinetobacter and of all bacteria capable of aerobic growth in a complex medium revealed that Acinetobacter constituted no less than 0.001% of the total heterotrophic aerobic population in soil and water and was one of the predominant organisms in some water samples.

Bacteriological Techniques↗
PubMed1974

Isolation and characterization of a generalized transducing bacteriophage for Acinetobacter.

A series of bacteriophages which grow in various strains of Acinetobacter have been isolated. One of these, phage P78, which forms turbid plaques on Acinetobacter strain 78 is specific for this particular host and fails to attack 389 other independently isolated strains of Acinetobacter. Phage P78 appears to be a temperate phage which lysogenizes its host. Various agents such as N-methyl-N'-nitro-N-nitrosoguanidine, diethyl sulfate, mitomycin C, and ultraviolet light are effective inducers of the lysogen. Phage lysates of wild-type cells are capable of transducing auxotrophs of strain 78 to prototrophy at frequencies ranging from 0.3 x 10(-7) to 34 x 10(-7) per plaque-forming unit adsorbed. To date, no linkage has been detected between any of the markers studied in two-factor crosses. Donor phage grown in one particular mutant, strain 78 (arg-1), has been shown to give rise to significantly higher transduction frequencies than when phage is grown on wild-type or other auxotrophic strains. Phage P78 is rapidly adsorbed to its bacterial host and has a latent period of 25 min, and infection results in a burst size of approximately 50. Some of the physical properties of phage P78 and its DNA are described.

Adsorption↗
PubMed1990

[A membrane-bound alanine aminopeptidase from Acinetobacter calcoaceticus. 3. Inhibition of the enzyme].

The alanine aminopeptidase from Acinetobacter calcoaceticus is inhibited by SH-reagents like p-hydroxymercuribenzote, Ellman's reagent, N-bromosuccinimide, and metal chelating agents like 1,10-phenanthroline. The AAP is competitively inhibited by L-amino acids such as leucine, phenylalanine, and valine having hydrophobic side chains. Bacitracin (Ki = 2.0.10(-6) mol/l) inhibits AAP stronger than puromycin (Ki = 8.0.10(-6) mol/l). In contrast, the Aeromonas aminopeptidase (EC 3.4.11.10) is stronger inhibited by bestatin (Ki = 1.8.10(-8) mol/l) than the membrane-bound AAP from Acinetobacter calcoaceticus. However, the binding of bestatin by both membrane-bound enzymes. Acinetobacter-AAP and microsomal aminopeptidase M (EC 3.4.11.2), with Ki values of 8.10(-6) mol/l is in the same range.

Actinobacillus↗
PubMed1981

Amino acid utilization and urine protein excretion in children treated with succinylated Acinetobacter glutaminase-asparaginase.

Amino acid utilization was evaluated in seven children with acute lymphocytic leukemia treated with succinylated Acinetobacter glutaminase-asparaginase. All patients received food p.o. ad libitum and glucose-electrolyte solutions i.v.; four patients received an i.v. amino acid supplement (1.5 g/kg/day). Although all patients were in negative energy balance, there was a significant linear regression between nitrogen balance and nitrogen intake during Days 1 to 7 and Days 8 to 14 of the study. The slope of the regression line, reflecting exogenous nitrogen utilization, was not significantly different from that found in healthy young men ingesting adequate or subadequate energy intakes. The Y-intercept (-210 mg/kg/day) indicated an obligatory nitrogen loss that was much greater than normal. Most of the nitrogen loss was due to urinary excretion. Ammonia and urea accounted for 77 to 91% of the urine nitrogen. Urinary glutamate accounted for 4 to 10% of this loss. Urine protein excretion was abnormally high in each of the patients, ranging from 987 to 3440 mg/day. Urine excretion of N-acetyl-beta-glucosaminidase and beta 2-microglobulin was also abnormally high, despite normal blood urea nitrogen and serum creatinine, suggesting that these children had renal tubular dysfunction. The antileukemic effect of succinylated Acinetobacter glutaminase-asparaginase did not appear to be altered by amino acid supplementation. These data indicate that amino acid supplementation can improve nutritional status in patients treated with succinylated Acinetobacter glutaminase-asparaginase.

Acetylglucosaminidase↗