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PubMed1978

[Arginine metabolism in Citrobacter].

The authors studied ways of utilization of arginine and of the products of its metabolism (ornithine, agmatine, and urea) in the microoganisms of Citrobacter genus. Arginine- and ornithine-decarboxylase activity was revealed by spectrophotometric method of decarboxylation products in the form of dinitrophenyl-derivatives in a small number of strains. Almost all the strains studied demonstrated a sufficiently high agmatine-ureohydrolase reaction. Arginase was constantly revealed. These microbes were capable of urea utilization in prolonged incubation.

Agmatine↗
PubMedDate not supplied

[Taxonomic study of "Citrobacter freundii" biochemical variants (author's transl)].

Biochemical variants (ornithine-decarboxylase-positive and beta-galactosidase-negative) of Citrobacter freundii were characterized using numerical taxonomy, determination of deoxyribonucleic acid (DNA) base composition and DNA-DNA hybridization. Three clusters were detected by numerical taxonomy based on the assimilation of 146 carbohydrates. The atypical strains were dispersed into two clusters along with typical C. freundii strains. Furthermore, m-hydroxybenzoate metabolism, determination of base composition and DNA reassociation show that all three clusters are closely related. Therefore, the biochemical variants form a biogroup within C. freundii rather than a separate species.

Base Composition↗
PubMed1983

[Characteristics of Proteus, Klebsiella, Enterobacter and Citrobacter strains isolated in urological infections].

The comparative study of more than 300 Proteus, Klebsiella, Enterobacter and Citrobacter strains isolated from patients with urological infections and parenteral infections of other localization, as well as from the feces of healthy persons has been carried out. The strains causing inflammatory processes in the urinary tract have been shown to possess no strict specificity. The ability of opportunistic enterobacteria to cause urinary tract lesions is their polydeterminant property ensured by the combination of different factors. A number of characteristics which can be considered as the markers of "nephritogenic" strains have been revealed. Thus, among Proteus mirabilis strains the largest percentage is constituted by strains fermenting sucrose and producing hemolysin. The urological pathogenicity of "nephritogenic" strains belonging to the genera Proteus, Klebsiella and Enterobacter has been found to be linked with their resistance to complement and their capacity for producing substances increasing capillary permeability. In C. freundii strains differences in O serogroups and a number of markers (the fermentation of raffinose, the formation of hemolysin and permeability factor) have been revealed. These data may be useful for the prognosis and evaluation of the course of urological infections.

Animals↗
PubMedDate not supplied

[Cytochrome composition and content of Citrobacter freundii].

Citrobacter freundii, strain 62, produces considerable amounts of cytochromes c and b when it grows in media with different carbon compounds under both aerobic anc anaerobic conditions. The content of cytochromes c increases under anaerobic conditions, particularly in the presence of formate or DMSO, and under aerobic conditions if formate is added. In contrast, the amount of cytochromes b decreased when the culture is grown in media with formate under anaerobic conditions. Cytochrome o is principal terminal oxidase in C. freundii. Under certain growth conditions, the microorganism, just as E. coli, produced also cytochromes a and d.

Aerobiosis↗
PubMed1981

Citrobacter diversus brain abscess and meningitis in neonates.

Brain abscess is an infrequent complication of meningitis, including cases caused by Gram-negative enteric bacteria in neonates. Because brain abscesses recently developed in four of five neonates with Citrobacter diversus meningitis at one institution, we reviewed cases of C diversus meningitis reported in the literature and those enrolled in the Neonatal Meningitis Cooperative Study Groups and reported to the Centers for Disease Control. Seventy-four cases in neonates were identified, and a brain abscess had developed in 41 (77%) of 53 patients for whom the information was available. This high frequency indicates the need for rapid diagnosis of this complication of C diversus meningitis.

Brain Abscess↗
PubMed1981

Fatal neonatal central nervous system infection caused by Citrobacter diversus.

Citrobacter diversus is a serious, albeit rare, offender of the central nervous system (CNS) in the neonatal period and in early infancy. We report here a case of neonatal CNS infection caused by C. diversus. The course of the illness was one of rapid deterioration, leading to recurrent seizures, coma and death. Since neonatal C. diversus CNS infection carries a grave prognosis, intraventricular administration of gentamicin should be considered.

Citrobacter↗
PubMedDate not supplied

[Conditions for the formation of molecular hydrogen by Citrobacter freundii].

Cell suspensions of Citrobacter freundii grown under anaerobic and aerobic conditions are capable of evolving molecular hydrogen. Hydrogen evolution is more active by the cells of anaerobic cultures in the exponential growth phase in the presence of reduced methylviologen or formate. The optimal temperature for hydrogen evolution from formate is about 40 degrees C, the optimal pH is 6.2 to 6.4. The presence of O2 in the gaseous phase inhibits hydrogen evolution by the cells; however the inhibition is incomplete and reversible. Nitrate also inhibits H2 formation from formate while fumarate does not inhibit the process.

Aerobiosis↗
PubMed1993

Structure and antigenic properties of Citrobacter freundii lipopolysaccharides.

Citrobacter freundii strain E69366 was detected in a colony immunoassay with a rabbit antiserum prepared to a strain of Escherichia coli belonging to serogroup O157. Lipopolysaccharide (LPS) was shown to contain the epitope(s) involved in antibody binding. LPS prepared from strain E69366, with hot phenol contained core-LPS that migrated to the water-phase and long-chain LPS that separated into the phenol-phase. A total of 36 strains of Cit. freundii were analysed for their LPS profiles by SDS-PAGE. Sixteen could be allocated into five groups (A(3), B(7), C(2), D(2) and E(2)) based on similarities in LPS profile. The remaining strains either expressed unique SDS-PAGE profiles (18) or did not express long-chain LPS (2). All strains with a profile 'A' reacted with the antiserum prepared to E. coli O157, whereas those with other profiles did not. The two strains of Cit. freundii expressing LPS profiles designated 'E' reacted with an antiserum prepared in rabbits to E. coli O45.

Adult↗
PubMed1995

Structural elucidation of the biological repeating unit of O-specific polysaccharide from Citrobacter serotype O41.

Sugar analysis of the O-specific polysaccharide produced by Citrobacter serotype O41 revealed the presence of a hexasaccharide repeating unit, which includes the unusual 3-amino-N-(D-3'-hydroxybutyryl)-3,6-dideoxy-D-galactosyl residue (Fuc3NAcyl). The structure of the repeating unit was determined by extensive use of homo- and heteronuclear two-dimensional NMR spectroscopy, including the application of long-range 1H-13C correlation experiments and NOE studies to establish the sequence of sugar units. Indentification of the Glc beta 1-->2Fuc3NAcyl beta 1-->6GlcNAc alpha 1-->sequence at the non-reducing terminus establishes the biological repeating unit of this O-specific polysaccharide as: -->2Glc beta 1-->Fuc3NAcyl-beta 1-->6GlcNAc alpha 1-->(Glc alpha 1-->2) 4Gal beta 1-->3GalNAc beta 1-->. This structure is similar to that found for the O-specific polysaccharide isolated from Hafnia alvei strain 1211 [Katzenellenbogen, E., Romanowska, E., Dabrowski, U. & Dabrowski, J. (1991) Eur. J. Biochem. 200, 401-407], which differs in having an acetyl substituent at O4 of the Fuc3NAcyl residue and a branch point of GalNAc alpha substituted by Glc beta at O3; these differences are responsible for the only weak serological cross-reactivity of the two strains.

Carbohydrate Sequence↗
PubMed1995

Site-directed mutagenesis of His343-->Ala in Citrobacter freundii tyrosine phenol-lyase. Effects on the kinetic mechanism and rate-determining step.

His343 in Citrobacter freundii tyrosine phenol-lyase is conserved in all known sequences of both tyrosine phenol-lyase and tryptophan indole-lyase; it is located near the active-site Lys257 in C. freundii tyrosine phenol-lyase [Antson, A. A., Demidkina, T. V., Gollnick, P., Danter, Z., Von Tersch, R.L., Long, J., Berezhnoy, S. N., Phillips, R. S., Harutyunyan, E. H. & Wilson, K. S. (1993) Biochemistry 32, 4195--4206]. In order to evaluate the role of His343 in the reaction mechanism of tyrosine phenol-lyase and tryptophan indole-lyase, we have mutated it to Ala; the former mutant is referred to as [H343A]tyrosine phenol lyase. All substrates for alpha, beta-elimination (except S-ethyl-L-cysteine) exhibited lower kcat (10-30%) and kcat/Km (1-10%) values with [H343A]tyrosine phenol-lyase than with the wild-type enzyme. The mutant also shows slower rates of deuterium isotope exchange for L-phenylalanine and L-methionine than does the wild type. The pH-dependent behavior in the reaction of 3-fluoro-L-tyrosine with wild-type tyrosine phenol-lyase is identical to that of L-tyrosine described previously [Kiick, D. M. & Phillips, R. S. (1988) Biochemistry 27, 7333-7338]. The pH profile of kcat/Km for this reaction exhibits two pKa values with an average of 7.7 +/- 0.2, indicating that the catalytic mechanism requires two essential basic groups. The pH profile of kcat/Km for 3-fluoro-L-tyrosine with [H343A]tyrosine phenol-lyase also exhibits two pKa values with an average of 7.8 +/- 0.3. However, kcat for 3-fluoro-L-tyrosine is pH-dependent for the mutant, exhibiting two pKa values with an average of about 7.8, whereas it is pH-independent for the wild type. Steady-state kinetic isotope effects on the reactions with wild-type and [H343A]tyrosine phenol-lyase were examined at various pH values. For the wild type, the values of the isotope effects on kcat and kcat/Km for 3-fluoro-L-[alpha-2H]-tyrosine are independent of pH and equal to 3.9 +/- 0.2 and 2.2 +/- 0.3, respectively, while the corresponding values for [H343A]tyrosine phenol-lyase are 5.4 +/- 0.2 and 3.8 +/- 0.3, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Alanine↗
PubMed1993

[Clonal spreading of a multidrug resistance Citrobacter freundii strain at a neonatal intensive care unit].

This paper reports on the epidemic spreading of a multiresistant Citrobacter (C.) freundii strain at a neonatal intensive care unit. A premature baby of the 27th week of pregnancy died from septic shock caused by this strain. According to the result of a statistical analysis of risk factors a connection between the colonization of neonates and the feeding with an enteral feeding tube was probably. This suspicion could be confirmed by the detection of the multiresistant strain in the infant formula. Plasmid analysis, examination of outer membrane proteins and lipopolysaccharides of these C. freundii strains demonstrated the identity of all isolates. The resistance to antibiotics of this multiresistant C. freundii clone was determined by a plasmid belonging to incompatibility group C with a molecular weight of 110 MDa. This plasmid was involved also in other nosocomial outbreaks. It persisted more than 7 years in the hospital flora of the intensive care unit.

Anti-Bacterial Agents↗
PubMed1996

Affinity purification and binding characteristics of Citrobacter freundii AmpR, the transcriptional regulator of the ampC beta-lactamase gene.

The transcriptional regulator of the Citrobacter freundii ampC beta-lactamase gene, AmpR, was purified as a single SDS/PAGE-gel band by using various techniques, including DNA-Sepharose 4B affinity chromatography. The purified AmpR consisted of a 32.5 kDa monomer that interacted with three operator sequences: two binding sequences, at positions -75 to -70 and -67 to -51 with respect to the transcriptional start site, were located in the LysR motif (-72 to -60), and the third sequence was at position -43 to -38. Equilibrium binding studies raise the possibility that the adjacent operator sequence could exert a positive influence on the ability of AmpR to bind to these sites.

Bacterial Proteins↗
PubMed1977

[Characteristics of bacteria of the genus Citrobacter, isolated from healthy children and children with different acute gastrointestinal diseases].

The authors examined 250 children suffering from various acute gastrointestinal diseases, and 100 healthy children. Positive cultures of bacteria belonging to the Citrobacter genus were obtained in 38% of the patients and in 20% of the healthy persons. There were revealed no cultural or biochemical differences between the strains isolated from the sick and healthy individuals. There were revealed no cultural or biochemical differences between the strains isolated from the sich and healthy persons. A total of 189 strains were identified serologically. Serological types 01, 03, 04, 08, 021, 022, the ones most frequently encountered in sick children, were absent or rarely found in the healthy. Sensitivity of the majority of the strians to the main antibiotics used in medical practice was weak; the strain isolated from the sick and healthy children failed to differ by the antibiotic sensitivity.

Acute Disease↗
PubMed1977

Morphogenesis of early 1, 2-dimethylhydrazine-induced lesions and latent period reduction of colon carcinogenesis in mice by a variant of Citrobacter freundii.

The morphogenesis of 1, 2-dimethylhydrazine (DMH)-induced lesions in the colon of outbred NIH Swiss mice was determined for up to 5 months of treatment. The effect of hyperplasia on DMH carcinogenesis was also evaluated by introducing a transient hyperplastic stimulus to the colon during the chronic weekly treatment regimen of DMH. The hyperplastic stimulus was a naturally occurring disease of mice, transmissible murine colonic hyperplasia, which is caused by a variant of Citrobacter freundii. In control mice, those not receiving the bacterium, weekly injections of the carcinogen induced neoplastic changes first detectable at two months of treatment in all segments of the colon and in both sexes. The changes increased in frequency and severity with time. Diffuse mucosal hyperpladia and chronic inflammatory and degenerative changes were also associated with DMH after prolonged treatment. The hyperplastic stimulus of C. freundii reduced the latent period for appearance of early DMH tumors, but it had no influence on already established DMH tumors.

Animals↗
PubMedDate not supplied

Neonatal meningitis and multiple brain abscesses due to Citrobacter diversus.

We report a fatal sporadic case of neonatal Citrobacter diversus meningitis with rapid clinical progression. At autopsy, multiple brain abscesses and abscesses in the spinal cord had complicated purulent meningitis. Septic omphalitis was identified as the most likely portal of entry.

Brain Abscess↗
PubMed1998

Cellulitis caused by Citrobacter diversus in a patient with multiple myeloma.

The most common cause of cellulitis is streptococci. Coagulase-negative staphylococci and gram-negative bacteria, such as Serratia spp., Proteus spp., and other Enterobacteriaceae may produce cellulitis in the immunocompromised patient. We report a case of Citrobacter diversus-induced cellulitis, resembling streptococcal infection, in a patient with multiple myeloma.

Anti-Infective Agents↗
PubMed1976

[Characteristics of strains of Citrobacter 037 (5396/38) isolated from guinea pigs in a gnotobiologic experiment].

No changes in the principal biochemical properties characteristic of the given genus occurred in a gnotobiological experiment of passing Citrobacter bacteria through microbe free and exmicrobe-free animals. Of 28 strains of this genus isolated in the course of investigation two strains lost their arginine-decarboxylase activity. In the cultures studied the quantitative content of the Vi-antigen had a tendency to reduction in comparison with the initial culture used for the association. some of the strains studied had one more common antigen with typhoid bacilli (strain Ty2-4446) along with theknown cross by the Vi-antigen. Bacteria of the Enterobacter and Excherichia genus isolated after the conventionalization had common antigens with typhoid bacilli (Ty2-4446).

Animals↗
PubMedDate not supplied

[Taxonomic positions of H2S-Enterobacteria in relation to the genus (Citrobacter) (author's transl)].

This work studies the classification, by numerical procedure, of 111 strains belonging to the family Enterobacteriaceae. Their taxonomic position is discussed, in relation to the genus Citrobacter, Levinea, Enterobacter, to which some appear to be closely associated. The study is based on the usual biochemical and nutritional characters as shown by the utilisation of substrates tested as sole sources of carbon and energy. Six hierarchical classes can thus be defined. Their degree of affinity with members of the Enterobacteriaceae groups or genera is discussed. The diverse origins of the strains examined (human, soil, aquatic) are certainly the cause for the individualization of the new classes.

Alcohols↗