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PubMed1989

Flavobacterium meningosepticum infections in a neonatal intensive care unit.

An outbreak of nosocomial infections by Flavobacterium meningosepticum in a neonatal intensive care unit is described. During a period of eleven weeks two patients presented with septicaemia and meningitis. In addition, nine patients were found to be colonized and three of these neonates developed septicaemia. The infected patients were treated with clindamycin and piperacillin. All the patients survived, but the neonates with meningitis developed hydrocephalus. An extensive bacteriological screening of the staff was negative, but in the ward environment, F. meningosepticum was found around sinks, on rubber stoppers for milk bottles and on "cleaned" teats. Several infection control measures were instituted. Established routines were revised, with particular emphasis on the handling of objects containing or in regular contact with water.

Anti-Bacterial Agents↗
PubMed1987

Genetic heterogeneity of Flavobacterium meningosepticum demonstrated by DNA-DNA hybridization.

DNA-DNA reassociation studies on 52 strains of Flavobacterium meningosepticum showed two main hybridization groups about 40-55% interrelated and comprising 4 and 48 strains respectively. The larger group could be further divided into four subgroups if differences in thermal stability of the reassociated duplexes were taken into consideration. Of a total of 20 strains isolated from cerebrospinal fluid, 18 were found in one subgroup of 28 strains, which also contained seven blood isolates. The results indicate that genetically defined subgroups within the species might differ with regard to pathogenic significance.

DNA, Bacterial↗
PubMed1987

Antimicrobial susceptibility of Flavobacterium meningosepticum strains identified by DNA-DNA hybridization.

Antimicrobial susceptibilities of 52 strains of Flavobacterium meningosepticum were determined by an agar plate dilution technique and by a tablet diffusion method. No useful susceptibility differences between the two main DNA relatedness groups within F. meningosepticum were found. All strains produced beta-lactamase and were resistant to most beta-lactam antibiotics. Ciprofloxacin, rifampicin and clindamycin appear to be the most promising for treating infections caused by F. meningosepticum.

Anti-Bacterial Agents↗
PubMed1989

Crossed immunoelectrophoretic analysis of Flavobacterium meningosepticum DNA hybridization groups I and II.

By means of crossed immunoelectrophoresis and crossed-line immunoelectrophoresis, antigens were compared from four strains and five strains, respectively, of Flavobacterium meningosepticum DNA hybridization groups I and II. Two reference antisera raised against the pooled antigens of each of the two DNA groups were used. The two reference antigen-antibody systems produced 81 and 51 immunoprecipitates, respectively, and within each group nearly all antigens were common to all strains, giving matching coefficients of 0.98-1.00. Group specific antigens were not detected. When antigens from individual strains from each group were compared to individual strains of the other group, however, 5-15 of the antigens were not cross-reactive, giving matching coefficients of 0.83-0.94. The antigenic relatedness between strains belonging to the two different groups was, therefore, just below the level commonly found for strains belonging to the same species. The results thus confirm the previously published differences detected by a DNA hybridization technique.

Antigens, Bacterial↗
PubMed1978

Flavobacterium meningosepticum meningitis: report of selected aspects.

Two patients developed meningitis due to Flavobacterium meningosepticum. Because of resistance to most available antimicrobial agents, intravenous and intraventricular erythromycin was administered to one patient. Subsequent development of resistance to erythromycin prompted the use of intravenous and intraventricular rifamycin, which eventually resulted in cure. Diagnosis of F. meningosepticum meningitis in the second patient was delayed, and appropriate therapy was not administered until 4 days prior to the patient's death. Of 82 previously published cases, only 4 occurred in adults. Therapy of meningitis due to this organism has been a difficult problem, and we suggest possible modes of therapy, based on our experience and a review of the literature.

Aged↗
PubMed1985

Biochemical properties of beta-lactamase produced by Flavobacterium odoratum.

A constitutively produced beta-lactamase was purified from Flavobacterium odoratum GN14053. The purified enzyme gave a single protein band on polyacrylamide gel electrophoresis. The isoelectric point was 5.8, and the molecular weight was estimated to be about 26,000. The enzyme activity was inhibited by EDTA, iodine, p-chloromercuribenzoate, HgCl2, and CuSO4 but not by clavulanic acid, sulbactam, imipenem, and cephamycin derivatives. The enzyme showed a broad substrate profile, hydrolyzing oxyiminocephalosporins, cephamycins, imipenem, and some penicillins.

Anti-Bacterial Agents↗
PubMed1999

Cloning of a Chryseobacterium (Flavobacterium) meningosepticum chromosomal gene (blaA(CME)) encoding an extended-spectrum class A beta-lactamase related to the Bacteroides cephalosporinases and the VEB-1 and PER beta-lactamases.

In addition to the BlaB metallo-beta-lactamase, Chryseobacterium (Flavobacterium) meningosepticum CCUG 4310 (NCTC 10585) constitutively produces a 31-kDa active-site serine beta-lactamase, named CME-1, with an alkaline isoelectric pH. The blaA(CME) gene that encodes the latter enzyme was isolated from a genomic library constructed in the Escherichia coli plasmid vector pACYC184 by screening for cefuroxime-resistant clones. Sequence analysis revealed that the CME-1 enzyme is a new class A beta-lactamase structurally divergent from the other members of this class, being most closely related to the VEB-1 (also named CEF-1) and PER beta-lactamases and the Bacteroides chromosomal cephalosporinases. The blaA(CME) determinant is located on the chromosome and exhibits features typical of those of C. meningosepticum resident genes. The CME-1 protein was purified from an E. coli strain that overexpresses the cloned gene via a T7-based expression system by means of an anion-exchange chromatography step followed by a gel permeation chromatography step. Kinetic parameters for several substrates were determined. CME-1 is a clavulanic acid-susceptible extended-spectrum beta-lactamase that hydrolyzes most cephalosporins, penicillins, and monobactams but that does not hydrolyze cephamycins and carbapenems. The enzyme exhibits strikingly different kinetic parameters for different classes of beta-lactams, with both K(m) and k(cat) values much higher for cephalosporins than for penicillins and monobactams. However, the variability of both kinetic parameters resulted in overall similar acylation rates (k(cat)/K(m) ratios) for all types of beta-lactam substrates.

Base Sequence↗
PubMed2000

Carbapenemases of Chryseobacterium (Flavobacterium) meningosepticum: distribution of blaB and characterization of a novel metallo-beta-lactamase gene, blaB3, in the type strain, NCTC 10016.

Genes encoding carbapenemases in 15 reference strains of Chryseobacterium (Flavobacterium) meningosepticum from the United Kingdom National Collection of Type Cultures and in one recent clinical isolate were investigated. All the strains hydrolyzed imipenem, but their levels of resistance to carbapenems varied, with imipenem and meropenem MICs ranging from 2 to >32 microg/ml. The blaB gene, which encodes a molecular-class B carbapenemase, was detected in only six reference strains and in clinical isolate 97/P/5448. The gene from 97/P/5448 had 98% nucleotide identity with the published sequence of blaB (from strain NCTC 10585) and was designated blaB2. A distinct carbapenemase gene, designated blaB3, was cloned from the type strain of C. meningosepticum, NCTC 10016. blaB3 had an open reading frame of 750 bp with 82% nucleotide identity to blaB and blaB2 and encoded a beta-lactamase of 249 amino acids, including the putative signal peptide. This beta-lactamase showed 87.6 and 86.7% amino acid homology with BlaB and BlaB2, respectively. blaB3 was detected in one other reference strain besides NCTC 10016, but the genetic basis of the carbapenemase activity detected in the other seven reference strains was not defined. Thus, neither blaB nor blaB3 was ubiquitous in the strains of C. meningosepticum studied, indicating that the reference strains may represent more than one bacterial species, each with its own intrinsic metallo-beta-lactamase. Further taxonomic studies of C. meningosepticum are necessary to resolve this topic. Chryseobacterium spp. are environmental organisms and occasional opportunist pathogens. They apparently represent a reservoir of diverse metallo-beta-lactamases, which potentially spread to gram-negative bacteria of greater clinical significance.

Amino Acid Sequence↗
PubMed2006

A protective immune response is generated in rainbow trout by an OmpH-like surface antigen (P18) of Flavobacterium psychrophilum.

Investigations of the surface characteristics of Flavobacterium psychrophilum, an important pathogen of fish, assisted us in identifying a surface protein termed P18. In the current study, we developed a simple and efficient procedure for the purification of this protein by a two-step method. First, P18 was selectively released from flavobacteria by a heat-HEPES treatment of the cells and then subjected to anion-exchange high-performance liquid chromatography. De novo sequencing was used to generate a fragmented peptide spectrum from purified P18. Comparison of two obtained peptide sequences with a partial genome sequence of F. psychrophilum (INRA, Jouy-en-Josas, France) identified one gene encoding a 166-amino-acid OmpH-like protein that mostly likely undergoes N-terminal cleavage of the 23-residue signal peptide. The susceptibility of the OmpH-like protein to proteinase K treatment and the bacteriostatic/bactericidal activities of anti-OmpH-like protein antibodies indicated that this protein is actually exposed on the surface of F. psychrophilum. Vaccination trials showed that the OmpH-like protein can induce a high titer of anti-OmpH-like protein antibodies which are protective. Taken together, these results suggest that this surface protein produced by F. psychrophilum could be used in future vaccine development as a promising candidate antigen.

Amino Acid Sequence↗
PubMed1978

Extracellular accumulation of a new amino acid, O-2-hydroxypropylhomoserine, from 1,2-propanediol by flavobacterium rigense.

During an investigation of microorganisms utilizing petrochemicals, a strain identified as Flavobacterium rigense was found to accumulate a new amino acid in a medium containing 1,2-propanediol as the sole carbon source. Cultural conditions for the accumulation of the product were investigated, and as a result, the yield was increased to 2.8 mg/ml after a 5-day incubation in a medium containing 8% 1,2-propanediol. The pure amino acid was isolated, and its structure was investigated. Elemental analysis and infrared, nuclear magnetic resonance, and mass spectral analyses indicated that the amino acids is O-2-hydroxypropylhomoserine.

Culture Media↗
PubMed1979

L-Glutamine formation by Flavobacterium rigense.

A penicillin-resistant mutant of Flavobacterium rigense designated as strain 703, FERM-P no. 3628, was obtained after ultraviolet treatment of F. rigense FERM-P no. 3556. The parent strain produces 0-2-hydroxypropylhomoserine from 1,2-propanediol. The mutant was found to be a good producer of L-glutamine. The physiological characteristics of strain 703 were different from the general group of L-glutamic acid-producing bacteria. Strain 703 required L-tryptophan and thiamine but not biotin for its growth. L-Glutamine formation on a specific basis, however, was independent of L-tryptophan and thiamine. Biotin and penicillin were also not effective. Only ammonium fumarate acted as an effective factor on L-glutamine formation. Accumulation of L-glutamine by strain 703 was 10 mg/ml at 30 degrees C for 48 h in a chemically defined medium containing 3% diammonium fumarate.

Flavobacterium↗
PubMed1981

Heparinase production by Flavobacterium heparinum.

Heparinase production by Flavobacterium heparinum in complex protein digest medium, with heparin employed as the inducer, has been studied and improved. The maximum productivity of heparinase has been increased 156-fold over that achieved by previously published methods to 375 U/liter per h in the complex medium. Rapid deactivation of heparinase activity, both specific and total, was observed at the onset of the stationary phase. Nutritional studies on growth and heparinase production showed an obligate requirement for L-histidine and no vitamin requirement. L-Methionine partially relieved the L-histidine requirement. A defined medium containing glucose, ammonium sulfate, basal salts, L-methionine, and L-histidine was developed for growth and heparinase production. The growth rate in this medium was 0.21 h-1, which is 40%, higher than that in complex medium. The maximum volumetric productivity of heparinase in the defined medium was increased to 1,475 U/liter per h, providing a 640-fold increase over that achieved by previously published methods. No rapid deactivation was observed. An examination of alternate inducers for heparinase showed that heparin degradation products, hyaluronic acid, heparin monosulfate, N-acetyl-D-glucosamine, and maltose, induce heparinase in complex medium. An Azure A assay was modified and fully developed to measure the heparin concentration during fermentation and the heparinase specific activity of crude extracts of F. heparinum obtained from sonication, thus negating the need for further purification to measure activity."

Culture Media↗
PubMed1983

Nutritional versatility of a starch-utilizing Flavobacterium at low substrate concentrations.

A starch-utilizing yellow-pigmented bacterium, isolated from tap water, was tested for the utilization of 64 natural compounds at a concentration of 1 g/liter by measuring colony growth on agar media. Only 12 carbohydrates and glycerol promoted growth. Growth experiments with the organism in pasteurized tap water supplied with mixtures of substrates at concentrations of 1 or 10 micrograms of C of each substrate per liter, followed by separate experiments with a number of carbohydrates at 10 micrograms of C per liter showed that of these 64 natural compounds only sucrose, maltose, raffinose, starch, and glycerol promoted growth at very low concentrations. Also maltotriose, -tetraose, -pentaose, -hexaose, and stachyose, which were not included in the mixtures, enhanced growth, and generation times of 3 to 5 h at 10 micrograms of C per liter were observed. The organism, which was tentatively identified as a Flavobacterium species, thus appeared to be highly specialized in the utilization of glycerol and a number of oligo- and polysaccharides at very low concentrations.

Flavobacterium↗
PubMed1985

Determination of the concentration of maltose- and starch-like compounds in drinking water by growth measurements with a well-defined strain of a Flavobacterium species.

The growth kinetics of Flavobacterium sp. strain S12 specialized in the utilization of glycerol, and a number of oligo- and polysaccharides were determined in batch-culture experiments at 15 degrees C in pasteurized tap water supplied with very low amounts of substrates. Kss for the growth on maltotriose, maltotetraose, maltopentaose, and maltohexaose were 0.03 microM or less and below those for glucose (1.5 microM) and maltose (0.16 microM). Kss for starch, amylose, and amylopectin were 8.4, 25.6, and 11.0 micrograms of C per liter, respectively. A yield of 2.3 X 10(7) CFU/micrograms of C on the oligo- and polysaccharides was calculated from the linear relationships observed between maximum colony counts in pasteurized tap water and the concentrations (usually below 25 micrograms of C per liter) of supplied compounds. The maximum colony counts of strain S12 grown in various types of raw water and tap water revealed that raw water contained only a few micrograms of maltose- and starch-like compounds per liter; in tap water the concentrations were all below 1 microgram of C and usually below 0.1 microgram of C per liter. The application of starch-based coagulant aids gave increased concentrations of maltose- and starch-like compounds in the water during treatment, but these concentrations were greatly reduced by coagulation and sedimentation, rapid sand filtration, and slow sand filtration.

Flavobacterium↗
PubMed1985

Isolation and characterization of Flavobacterium strains that degrade pentachlorophenol.

Bacteria able to mineralize 100 to 200 ppm of pentachlorophenol (PCP) were isolated by selective enrichment from PCP-contaminated soils from three geographic areas of Minnesota. Although differing somewhat in their responses to various biochemical and biophysical tests, all strains were assigned to the genus Flavobacterium. Five representative strains were examined in detail. All strains metabolized PCP as a sole source of carbon and energy; 73 to 83% of all carbon in the form of [U-14C]PCP was returned as 14CO2, with full liberation of chlorine as chloride. A comparison between strains in their ability to metabolize PCP showed some strains to be more efficient than others. Guanine-plus-cytosine contents of DNA ranged from 58.8 to 63.8%, and DNA/DNA hybridization studies with total DNA digests suggested substantial genetic homology between strains. All strains were shown to possess an 80- to 100-kilobase plasmid, and evidence suggested the presence of a larger plasmid (greater than 200 kilobases).

Chlorophenols↗
PubMed1986

Sulfur regulation of heparinase and sulfatases in Flavobacterium heparinum.

Sulfur regulation of heparinase synthesis and sulfatase synthesis was studied in Flavobacterium heparinum. Heparinase synthesis was strongly repressed by sulfate and L-cysteine, while the activity of this enzyme showed little or no inhibition by these compounds. Heparinase was synthesized in the absence of heparin when L-methionine was used as the sole sulfur source. The sulfatases produced by F. heparinum, which include the sulfatases involved in heparin catabolism, were also studied. At least some of the sulfatase activity was regulated by sulfur compounds in a manner similar to heparinase regulation. L-Cysteic acid and taurine were not suitable sulfur sources to support the growth of F. heparinum.

Ammonium Sulfate↗
PubMed1988

Dissimilar plasmids isolated from Pseudomonas diminuta MG and a Flavobacterium sp. (ATCC 27551) contain identical opd genes.

The opd (organophosphate-degrading) gene derived from a 43-kilobase-pair plasmid (pSM55) of a Flavobacterium sp. (ATCC 27551) has a sequence identical to that of the plasmid-borne gene of Pseudomonas diminuta. Hybridization studies with DNA fragments obtained by restriction endonuclease digestion of plasmid DNAs demonstrated that the identical opd sequences were encoded on dissimilar plasmids from the two sources.

Base Sequence↗