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PubMed1980

Clinical and laboratory characteristics of Achromobacter xylosoxidans infection.

Achromobacter xylosoxidans was isolated from six patients. The organism causes opportunistic infections in patients who are compromised. A. xylosoxidans is a catalase- and oxidase-positive, motile, gram-negative rod that oxidizes xylose and glucose. The organism exists in a water environment and may be confused with Pseudomonas species. Unlike pseudomonas, achromobacter has peritrichous flagella. The clinical and laboratory characteristics of A. xylosoxidans are presented.

Adolescent↗
PubMed1993

Cellular fatty acid compositions of "Achromobacter groups B and E".

Strains of "Achromobacter groups B and E" were examined for cellular fatty acid (CFA) composition to evaluate their chemical relatedness to known bacterial species and groups. The CFAs were liberated from whole cells by base hydrolysis, methylated, and analyzed by capillary gas-liquid chromatography. The CFA profiles of the two groups were identical and were distinct from CFA profiles of all other bacteria we have previously tested. These data provide support for results from whole-cell protein pattern analysis and DNA-DNA and rRNA-DNA hybridization studies, which show that "Achromobacter groups B and E" are biotypes of a single new genus and species.

Alcaligenes↗
PubMed1979

Achromobacter species (CDC group Vd): morphological and biochemical characterization.

Twenty-three isolates of Achromobacter species (CDC group Vd) were examined morphologically and biochemically. Gram stains revealed gram-variable bacilli frequently curved or hooked at one pole and often coryneform in shape and arrangement. Electron microscopy revealed the presence of extracellular material in polar accumulations and demonstrated the polar flagella arrangement seen by light microscopy to be lateral. Two colony types were produced; one was minute and watery at 24 h (35 degrees C) progressing to large, mucoid colonies at 48 h, and the other type was shiny, glistening, opaque but nonmucoid. All isolates grew on MacConkey agar and produced catalase, oxidase, and urease. Most grew on salmonella-shigella agar, reduced nitrate to nitrite and gas, hydrolyzed esculin, deaminated phenylalanine (2 to 4 days) and produced H2S in triple sugar iron agar (4 to 12 days). Oxidation of carbohydrates was weak, delayed, and limited to glucose and xylose. Two isolates also oxidized maltose, mannitol, and sucrose. The ability of miniaturized "nonfermenter" kits to identify Achromobacter species was tested. The Minitek (Baltimore Biological Laboratory, Cockeysville, Md.) and N/F (Corning, Roslyn, N.Y.) systems, respectively, identified 21 and 19 of the 23 isolates, whereas the Oxi/Ferm (Roche, Nutley, N.J.) identified 13 and the API 20E (Analytab Products, Plainview, N.Y.) identified only 3.

Alcaligenes↗
PubMed1983

Comparative study of the beta-lactamase activity found in Achromobacter.

A survey of 21 clinical isolates of Achromobacter species demonstrated a high level of beta-lactamase activity in all strains tested. The beta-lactamases were characterized by isoelectric focusing, purification by affinity chromatography, determination of molecular weight, immunological identity, and genetic analysis. At least three distinct patterns of beta-lactamases were found in 19 strains. The kinetic values Km and Vmax measured by a microacidimetric method showed that all three types of enzymes are cephalosporinases and did not hydrolyse oxacillin, cloxacillin, and methicillin. Two of the three types of cephalosporinases studied, namely MULB 901 (isoelectric point (pI)7.4) and MULB 905(pI 9.3) are enzymes mediated by genes of chromosomal origin. The MULB 906 (pI 8.1) enzyme, however, which has been previously shown to be mediated by an 8.2 MDal nonconjugative plasmid, showed hydrolysis of cefoxitime, cefotaxin, and moxalactam by the bioassay. In all cases, beta-lactamase synthesis appeared constitutive. This study confirms that beta-lactamase activity is commonly found in Achromobacter and that these enzymes are different and of clinical interest when compared with those observed in other Gram-negative bacteria.

Alcaligenes↗
PubMed1992

Inhibition of Achromobacter protease I by lysinal derivatives.

Z-Val-, Z-Pro-, Z-Leu-Leu-, and Z-Leu-Pro-lysinals and BZ-DL-lysinal were chemically synthesized and tested as novel inhibitors for Achromobacter protease I (API), a lysine-specific serine protease. Among the lysinal derivatives tested, Z-Val-lysinal was the most potent competitive inhibitor, its Ki being estimated as 6.5 nM in an esterolytic assay with Tos-Lys-OMe. In an amidolytic assay, Z-Leu-Leu-lysinal was the most potent inhibitor and the apparent mode of inhibition was non-competitive. The Kis of the other lysinal derivatives in both esterolytic and amidolytic assays were more than 10(3) times lower than that of leupeptin. Z-Val-lysinol, lacking the aldehyde group, was a poor competitive inhibitor. These results suggest that acyl-, acylaminoacyl-, and acylpeptidyllysinals function as a transition-state inhibitor for Achromobacter protease I.

Alcaligenes↗
PubMed1992

Prosthetic knee infection due to Achromobacter xylosoxidans.

Achromobacter xylosoxidans is an aerobic gram negative organism that has been infrequently implicated in clinical infections in a variety of anatomical sites. We describe a case of a prosthetic knee infection due to Achromobacter xylosoxidans in a patient with rheumatoid arthritis receiving high dose prednisone.

Alcaligenes↗
PubMed1989

Cloning, nucleotide sequence, and expression of Achromobacter protease I gene.

Achromobacter protease I (API) is a lysine-specific serine protease which hydrolyzes specifically the lysyl peptide bond. A gene coding for API was cloned from Achromobacter lyticus M497-1. Nucleotide sequence of the cloned DNA fragment revealed that the gene coded for a single polypeptide chain of 653 amino acids. The N-terminal 205 amino acids, including signal peptide and the threonine/serine-rich C-terminal 180 amino acids are flanking the 268 amino acid-mature protein which was identified by protein sequencing. Escherichia coli carrying a plasmid containing the cloned API gene overproduced and secreted a protein of Mr 50,000 (API') into the periplasm. This protein exhibited a distinct endopeptidase activity specific for lysyl bonds as well. The N-terminal amino acid sequence of API' was the same as mature API, suggesting that the enzyme retained the C-terminal extended peptide chain. The present experiments indicate that API, an extracellular protease produced by gram-negative bacteria, is synthesized in vivo as a precursor protein bearing long extended peptide chains at both N and C termini.

Alcaligenes↗
PubMed1983

Cultivation of the bacterial strain Achromobacter delicatulus, producing an exocellular polyglucan-type polysaccharide in the fermentation tank FU-6.

Growth processes and biosynthesis of the exocellular polyglucan-type polysaccharide, produced by the bacteria Achromobacter delicatulus, were studied in the laboratory fermentation apparatus FU-6 under three completely different aeration systems. The purpose of this study was to find the most economical way of the polysaccharide biosynthesis. The growth rate and the synthesis of the exopolysaccharide were not limited either by the oxygen transfer or glucose content under the conditions examined. The best construction proved to be the fermentation tank with the lowspeed agitation system. In the case of the bacterial strain Achromobacter delicatulus, producing huge amounts of the thick slimy polyglucan exopolysaccharide, the industrial production may develop without any principal technical difficulties.

Alcaligenes↗
PubMed1964

FURTHER OBSERVATIONS ON MIMA POLYMORPHA AND ACHROMOBACTER (BACTERIUM) ANITRATUM.

Further investigations on the morphology, biochemical reactions, and serological relationships of strains of Mima polymorpha and Achromobacter (Bacterium) anitratum are reported. The results seem to indicate such a close relationship that it may yet be necessary to reconsider the nomenclature of these organisms.

Achromobacter↗
PubMed2003

Isolation and characterization of a new strain of Achromobacter sp. with beta-lactam antibiotic acylase activity.

A bacterial strain producing a beta-lactam antibiotic acylase, able to hydrolyze ampicillin to 6-aminopenicillanic acid more efficiently than penicillin G, was isolated from soil and characterized. The isolate was identified as Achromobacter sp. using the phenotypic characteristics, composition of cellular fatty acids and 16S rRNA gene sequence. The enzyme synthesis was fully induced by phenylacetic acid (PAA) at a concentration of 2 g l(-1). PAA at concentrations up to 12 g l(-1) had no negative effect on the specific activity of acylase and biomass production, but slowed down the specific growth rate. Benzoic or 4-hydroxyphenylacetic acids can also induce synthesis of the enzyme. The inducers were metabolized in all cases. Acylase activity in cell-free extracts was determined with various substrates; ampicillin, cephalexin and amoxicillin were hydrolyzed 1.5- and 2-times faster than penicillin G. A high stability of acylase activity was observed over a wide range of pH (5.0-8.5) and at temperatures above 55 degrees C.

Achromobacter↗
PubMed2005

Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit.

Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under XbaI restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine atomizers. The use of diluted chlorhexidine via atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.

Achromobacter denitrificans↗
PubMed2006

Direct estimation of the oxygen requirements of Achromobacter xylosoxidans for aerobic degradation of monoaromatic hydrocarbons (BTEX) in a bioscrubber.

The O2 requirements for biomass production and supplying maintenance energy demands during the degradation of both benzene and ethylbenzene by Achromobacter xylosoxidans Y234 were measured using a newly proposed technique involving a bioscrubber. Using this approach, relevant microbial parameter estimates were directly and simultaneously obtained via linear regression of pseudo steady-state data. For benzene and ethylbenzene, the biomass yield on O2, Y(X/O2), was estimated on a cell dry weight (CDW) basis as 1.96 +/- 0.25 mg CDW mgO2(-1) and 0.98 +/- 0.17 mg CDW mgO2(-1), while the specific rate of O2 consumption for maintenance, m(O2), was estimated as 0.041 +/- 0.008 mgO(2) mg CDW(-1) h(-1) and 0.053 +/- 0.022 mgO(2) mg CDW(-1) h(-1), respectively.

Achromobacter↗
PubMed2004

pH-profile crystal structure studies of C-terminal despentapeptide nitrite reductase from Achromobacter cycloclastes.

Crystal structures of C-terminal despentapeptide nitrite reductase (NiRc-5) from Achromobacter cycloclastes were determined from 1.9 to 2.3A at pH 5.0, 5.4, and 6.2. NiRc-5, that has lost about 30% activity, is found to possess quite similar trimeric structures as the native enzyme. Electron density and copper content measurements indicate that the activity loss is not caused by the release of type 2 copper (T2Cu). pH-profile structural comparisons with native enzyme reveal that the T2Cu active center in NiRc-5 is perturbed, accounting for the partial loss of enzyme activity. This perturbation likely results from the less constrained conformations of two catalytic residues, Asp98 and His255. Hydrogen bonding analysis shows that the deletion of five residues causes a loss of more than half the intersubunit hydrogen bonds mediated by C-terminal tail. This study shows that the C-terminal tail plays an important role in controlling the conformations around the T2Cu site at the subunit interface, and helps keep the optimum microenvironment of active center for the full enzyme activity of AcNiR.

Achromobacter cycloclastes↗
PubMed2005

Roles of Trp144 and Tyr203 in copper-containing nitrite reductase from Achromobacter cycloclastes IAM1013.

The roles of the Trp144 and Tyr203 residues near the type 1 Cu site of Achromobacter cycloclastes nitrite reductase (AcNIR) have been examined with mutants of AcNIR. Tyr203 is located on the protein surface near the type 1 Cu site of AcNIR, and Trp144 is between the Tyr203 and the type 1 Cu center in AcNIR. Single mutation of Trp144 or Tyr203 in AcNIR to Leu resulted in decreased rate constants of intermolecular electron transfer from its cognate pseudoazurin (AcPAZ) (k(ET)=1.9x10(5), 2.2x10(5), and 7.3x10(5)M(-1)s(-1) for W144L, Y203L, and wild-type AcNIR, respectively). The intermolecular electron transfer rate constant of double mutant AcNIR (W144L/Y203L) was the same as those of single mutants (k(ET)=1.9x10(5)M(-1)s(-1) for W144L/Y203L). The redox potentials, coordination structures of the type 1 Cu, and the enzyme activities of AcNIR were affected little by the mutation.

Achromobacter cycloclastes↗
PubMed2005

Crystal structure of C-terminal desundecapeptide nitrite reductase from Achromobacter cycloclastes.

Monoclinic crystal structure of C-terminal desundecapeptide nitrite reductase (NiRc-11) from Achromobacter cycloclastes was determined at 2.6A. NiRc-11 exists as a loose trimer in the crystal. Deletion of 11 residues eliminates all intersubunit hydrogen bonds mediated by the C-terminal tail. The rigid irregular coil 105-112, which constitutes part of the sidewall of the active site pocket, undergoes conformational changes and becomes highly flexible in NiRc-11. Correspondingly, the linker segments between the two copper sites 95-100 and 135-136 are partly relaxed in conformation, which leads to disrupted active site microenvironments responsible for the activity loss and spectral change of NiRc-11. Comparison with the native structure revealed a bulky residue Met331 fastened by hydrogen bonding, which may play a direct role in keeping the right copper site geometry by protruding its side chain against the irregular coil 105-112. Sequence alignment showed that the bulky residue is conserved at position 331, indicating an equal importance of C-terminal segment in other copper-containing nitrite reductases.

Achromobacter cycloclastes↗
PubMed2005

Imipenem-resistant Achromobacter xylosoxidans carrying blaVIM-2-containing class 1 integron.

We characterized seven isolates of imipenem-resistant Achromobacter xylosoxidans that were isolated from patients hospitalized in the intensive care unit at a tertiary hospital in Korea during 2001 to 2003. From the analysis with an isoelectric focusing, polymerase chain reaction, and sequencing methods, all isolates were found to produce VIM-2, OXA-30, and chromosomal AmpC beta-lactamase with a pI of 8.4. They showed a similar antibiogram, which were resistant to all tested aminoglycosides as well as beta-lactams including imipenem (16-32 mg/L) and aztreonam (128 mg/L), and a same DNA fingerprinting pattern by random amplified polymorphic DNA analysis, suggesting that these originated from a single clone. From the analysis of integron structure carried by an isolate of A. xylosoxidans CBU1760, bla(VIM-2) was found to be part of a gene cassette carried on a class 1 integron (3.4 kb) containing three aacA4 gene cassettes. This is the first report of bla(VIM-2) in A. xylosoxidans.

Achromobacter denitrificans↗
PubMed2005

Cloning, sequence analysis and expression of the gene encoding a novel wide-spectrum amidase belonging to the amidase signature superfamily from Achromobacter xylosoxidans.

Amidases are very important enzymes for industrial biocatalysis. We scored a novel amidase by screening the Achromobacter xylosoxidans gene library with cephalosporin analogous amides. The gene coding for the enzyme, designated ana, was cloned, sequenced and overexpressed in Escherichia coli. Sequence analysis of ana showed it to be an amidase signature family member. Interestingly, we noted that almost all Ana homologous amidases are from human pathogens responsible for chronic lung infections. Knowing the genetic context of Ana and its homologous amidases, we suggest that they could be a part of transposon structure. Ana can efficiently hydrolyze a series of cephalosporin analogous amides, including amides with an aninine, p-nitro-aninine, and beta-naphthylamine moiety, while cephalosporin could not serve as its substrate.

Achromobacter denitrificans↗
PubMed2006

Chronic infection with Achromobacter xylosoxidans in cystic fibrosis patients; a retrospective case control study.

BACKGROUND: In cystic fibrosis (CF), chronic infection of the airways with Achromobacter xylosoxidans have become more frequent. The pathogenic role of this is yet unclear. METHODS: A retrospective case-control study of all patients chronically infected with A. xylosoxidans for at least 3 years. 15 patients (6 males) with chronic A. xylosoxidans infection were matched by age, FEV(1) and body mass index z-score to 15 controls (7 males) at the time of establishment of chronic infection. Clinical parameters of the groups were compared from the time of establishment of chronic infection until spring 2006, giving a follow-up time of 3-11 years. Chest X-rays taken 3 years prior to establishment of chronic infection and after 3 years of chronic infection were compared using a modified Brasfield score. Finally, strains from individual patients were analysed using PFGE to investigate possible cross-infection. RESULTS: The median slope of decline of FEV(1) in the case group changed from +3.1% to -0.5% predicted/year (p<0.002). In the control group, median slope of decline in FEV(1) changed from +1.5% to -0.4% predicted/year (n.s.). Median slope of decline in FVC in the case group changed from +3.5% to -0.5% predicted/year (p<0.002). In the control group, median slope of decline in FVC changed from +1.7% to +0.4% predicted/year (n.s.). No significant difference in the slopes of decline of FEV(1) or FVC was found between the case group and the control group at either time. Change in BMI z-score was calculated for each group before and during chronic infection. No difference was found between the groups at any time or within a group. Specific antibodies against A. xylosoxidans were measured in patients with chronic infection. Patients with rapidly increasing antibody levels showed significantly faster deterioration in FEV(1) (p<0.05) and FVC (p<0.02). Chest X-ray scores increased in 6 of 10 chronically infected patients and in 3 of 10 controls (n.s.). Eight patients harboured a common A. xylosoxidans strain, indicating either cross-infection or a common source. CONCLUSION: A. xylosoxidans may lead to a decline in lung function in a subgroup of chronically infected CF patients characterised by a rapid increase in specific precipitating antibodies. Cross-infection may possibly occur.

Achromobacter denitrificans↗