Citrobacter Intermedius Research Articles

Incidence of Urinary Tract Infections (UTI) amongst Patients Attending Primary Health Centres in Anambra State

Urinary tract infections (UTIs) are one of the most prevalent extra-intestinal bacterial infections. It is a common disease encountered in medical practice affecting people of all ages, from neonate to geriatric age group. These infections are on the increase for outpatients attending Primary Health Centres in Anambra State, Nigeria, therefore the need for this study. The prevalence rate of urinary tract infection, age distribution and influence of sex were determined. Susceptibility pattern of the infectious organisms to antimicrobial agent were examined. Clean-catch midstream urine samples were collected and examined. Out of 3000 urine samples examined, 528 bacterial isolates were recovered and characterized. These include: Escherichia coli (24.2%), Klebsiella spp. (18.2%), Staphylococcus aureus (18.2%), Proteus mirabilis (9.1%), Pseudomonas aeruginosa (9.1%), Enterococcus faecalis (9.1%), Citrobacter intermedius (6.1%) and Staphylococcus saprophyticus (6.1%). More females (52%) were infected than males (48%) and in both sexes, the highest incidence was found amongst the age group, 26 - 38 years. Gram negative rods had the highest incidence in both sexes. Among the towns in Anambra state, Umunya in southern province was observed to have the highest incidence rate of UTI. Susceptibility test of the bacterial isolates to antimicrobial agents showed that Staphylococcus aureus was sensitive to Cephalexin, Penicillin V, Erythromycin and Gentamycin while Pseudomonas aeruginosa was resistant to all the antibiotics. Escherichia coli and Klebsiella spp. were resistant to all the antibiotics except Gentamycin while Citrobacter intermedius was resistant only to Cephalexin and Erythromycin. This study provides the evidence of urinary tract infections amongst outpatients of primary health centres and the drugs for their control.

Characterization of microorganisms from Sitakunda hot spring

Water, leaf, stone and sand samples from Sitakunda hot spring were studied and the microorganisms isolated from these samples were thoroughly characterized. The pH of the collected samples was found to range from 8.5 to 8.9 and the recorded temperature varied from 26.1 to 29.8 ºC during winter season. BOD of the collected water samples ranged from 10 to 92 mg/L, while COD was almost zero. The total alkalinity and chlorine content ranged from 12 to 20 mg/L and 13.9 to 18.3 gm/L respectively. Quantitative enumeration of bacterial population showed the range of 8.0×102 to 3.8×105 cfu/ml or gm sample. All the 9 selected isolates were identified as Bacillus coagulans (S1B4), Bacillus laterosporus (SB18), Bacillus megaterium (S2B11), Bacillus popilliae (S4P1), Bacillus firmus (S5B1), Citrobacter intermedius (S4B17), Listeria monocytogenes (S1B1), Listeria denitrificans (S2B) and Pseudomonas mendocina (S4P3). Bacillus laterosporus, Bacillus megaterium and Listeria denitrificans showed better growth in presence of methane gas in nutrient broth. By direct microscopic observation 7 genera of cyanobacteria (Arthrospria, Microcoleus, Oscillatoria, Schyzothrix, Scytonema, Nostoc and Gloeocapsa) and 4 genera of diatoms (Gomphonema, Melosira, Navicula and Pinnularia) were detected in the water sample DOI: http://dx.doi.org/10.3329/cujbs.v4i1.13394 The Chittagong Univ. J. B. Sci.,Vol. 4(1&2):107-117, 2009

Evaluation of Screening Methods for the Isolation of Biosurfactant Producing Marine Bacteria

Hemolytic assay, bacterial adhesion to hydrocarbons (BATH) assay, drop collapse assay, oil spreading assay, emulsification assay and surface tension measurement were compared for their reliability and ease of use to screen biosurfactant producing bacteria. 105 bacterial strains were screened for their biosurfactant production. Results from screening methods revealed that hemolytic and BATH assays are not reliable methods to check biosurfactant production because hemolytic assay relies on lysis of blood cells, which can be caused by compounds produced by microbes other than the biosurfactants. In that case hemolytic assay may include strains that do not produce biosurfactant. BATH assay relies on hydrophobicity or adherence of cells with hydrophobic compounds. Results obtained in BATH assay for three bacterial isolates, Branhamella catarrhalis, Citrobacter intermedius and Klebsiella ozaenae were positive, but when the same isolates screened for drop collapse, oil spreading, and surface tension measurement the results were negative. This indicates that these bacterial cells are either acting as biosurfactant themselves (cell surface) or they don’t have the ability to produce biosurfactants. In conclusion, drop collapse and oil spreading assays are reliable methods to screen large number of samples. However, for confirmation surface tension measurement can be used at the end. Another interesting finding in this study was the use of crude oil as hydrophobic substrate for the isolation of biosurfactant producing bacterial strains; this approach may be useful during the initial isolation of biosurfactant producing bacteria to reduce the number of strains to be screened.

Methionine γ-lyase: Mechanistic deductions from the kinetic pH-effects: The role of the ionic state of a substrate in the enzymatic activity

We have studied and compared the pH-dependencies of the main kinetic parameters for the α,γ-elimination reactions of methionine γ-lyase (MGL) of Citrobacter intermedius with natural substrate, l-methionine, with its phosphinic analogue, and for α,β-elimination reaction with S-methyl- l-cysteine. From the pH-dependency of k cat/ K m for the reaction with l-methionine we have concluded that MGL is selective with respect to the zwitterionic form of its natural substrate. For the reaction of MGL with 1-amino-3-methylthiopropylphosphinic acid the p K a of the substrate's amino group, equal to 7.55, is not reflected in the pH-profile of k cat/ K m. Consequently, the enzyme does not manifest well-defined selectivity with respect to the zwitterion and anion ionic forms of the substrate. The ascending limbs of pH-dependencies of k cat/ K m for reactions with l-methionine and S-methyl- l-cysteine are controlled by a single p K a equal to 7.1–7.2, while for the reaction with 1-amino-3-methylthiopropylphosphinic acid two equal p K as of 6.2 were found in the respective pH-profile. The descending limbs of pH-dependencies of k cat/ K m for the reactions with S-methyl- l-cysteine and racemic 1-amino-3-methylthiopropylphosphinic acid are very similar and are controlled by two acidic groups having average p K a values of 8.7. On the basis of these results we suggest a mechanism of catalytic action of MGL. According to this mechanism Tyr 113, in its conjugated base form, acts as an acceptor of the proton from the amino group of the substrate upon its binding in the active site. Elimination of the leaving thiol groups during both α,γ- and α,β-elimination reactions is assisted by the acidic groups of Tyr 113 and Tyr 58. Both tyrosyl residues are able to fulfill this catalytic function with different efficiencies depending on the type of elimination reaction. Tyr 113 residue plays the determining role in the α,γ-elimination, and Tyr 58 — in the α,β-elimination process.

ChemInform Abstract: A Phosphinic Analogue of Methionine Is a Substrate of L‐Methionine‐γ‐lyase and Induces the Synthesis of the Enzyme in Citrobacter intermedius Cells.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A phosphinic analogue of methionine is a substrate of L-methionine-γ-lyase and induces the synthesis of the enzyme in Citrobacter intermedius cells

1-Amino-3-(methylthio)propylphosphinic acid likewise methionine, is a substrate in α,γ-elimination and γ-substitution reactions catalysed by pyridoxal-5'-phosphate-dependent L-methionine-γ-lyase and is capable to induce the synthesis of this enzyme inCitrobacter intermediuscells as does L-methionine.

Poly(vinyl alcohol) cryogels employed as matrices for cell immobilization. 2. Entrapped cells resemble porous fillers in their effects on the properties of PVA-cryogel carrier

Poly(vinyl alcohol) cryogels which are prepared by freeze-thawing of concentrated aqueous solutions of the polymer are used as carriers for cell immobilization. Biomass entrapment causes a variation in the mechanical properties of the composites obtained. With rheological testing and scanning electron microscopy, it was shown that cells which manifested the reinforcing action in respect to the carrier resembled in their “physical behavior” simple model inorganic fillers of definite porosity. This porosity allows macromolecules of gel-forming polymer to penetrate into the inner regions of the particles and promote the formation of tight contacts between the matrix and dispersed phase, such as entrapped cells in particular. The immobilized cultures and model fillers were as follows: Citrobacter intermedius, Zymomonasas mobilis, and Pseudomonas sp. bacteria, Saccharomyces cerevisiae native and modified yeast cells, titanium dioxide, silica gels, and controlled pore glass.

L-methionine-γ-lyase in Citrobacter intermedius cells: Stereochemical requirements with respect to the thiol structure

The specificity of l-methionine-γ-lyase with respect to the stereochemical structure of the thiol substrate in the γ-substitution reaction has been demonstrated. Cells of Citrobacter intermedius containing l-methionine-γ-lyase catalyze the exchange reactions between l-methionine and 2-propylthiol or 2-butylthiol which leads to the formation of s-2-propylhomocysteine and s-2-butylhomocysteine, respectively. The yields of these products are comparable to the yield of s-butylhomocysteine in the reaction of normal butylthiol with l-methionine, thus 2-propylthiol and 2-butylthiol are effective substrates of l-methionine-γ-lyase. On the other hand in the reaction of 3-pentylthiol, only traces of the expected product, s-3-pentylhomocysteine, were formed and in the case of 2-methyl-2-butylthiol, the expected product of γ-substitution, s-2-methyl-2-butylhomocysteine, was not formed at all. In the reaction with racemic 2-butylthiol, only one diastereomer of s-2-butylhomocysteine was obtained. The unreacted 2-butylthiol isolated after the reaction catalyzed by partially purified preparation of l-methionine-γ-lyase was enriched with ( R)-enantiomer which indicated the preferential reaction of the ( S)-enantiomer.

The polypeptide chain fold in tyrosine phenol-lyase, a pyridoxal-5′-phosphate-dependent enzyme

The tyrosine phenol lyase (EC 4.1.99.2) from Citrobacter intermedius has been crystallised in the apo form by vapour diffusion. The space group is P2 12 12. The unit cell has dimensions a = 76.0 Å, b = 138.3 Å, c = 93.5 Å and it contains two subunits of the tetrameric molecule in the asymmetric unit, Diffraction data for the native enzyme and two heavy atom derivatives have been collected with synchrotron radiation and an image plate scanners. The structure has been solved at 2.7 Å resolution by isomorphous replacement with subsequent modification of the phases by averaging the density around the non-crystallographic symmetry axis. The electron density maps clearly show the relative orientation of the subunits and most of the trace of the polypeptide chain. Each subunit consists of two domains. The topology of the large domain appears to be similar to that of the aminotransferases.

A weak adaptive response to alkylation damage in Salmonella typhimurium

An efficient adaptive response to alkylation damage was observed in several enterobacterial species, including Klebsiella aerogenes, Shigella sonnei, Shigella boydii, Escherichia alkalescens, Escherichia hermanii, and Escherichia fergusonii. Increased O6-methylguanine-DNA and methylphosphotriester-DNA methyltransferase activities correlated with the induction of a 39-kDa protein recognized by monoclonal antibodies raised against the Escherichia coli Ada protein. Induced methyltransferase activities were similarly observed in Aerobacter aerogenes and Citrobacter intermedius, although no antigenically cross-reacting material was present. Weak induction of a 39-kDa protein immunologically related to the E. coli Ada protein occurred in Salmonella typhimurium. This protein encoded by the cloned S. typhimurium ada gene was shown to be an active methyltransferase which repaired O6-methylguanine and methylphosphotriesters in DNA as efficiently as did the E. coli Ada protein. However, the mehtyltransferase activity of the weakly induced 39-kDa protein in S. typhimurium was not detected, apparently because it was self-methylated and thus inactivated during the adaptive N-methyl-N-nitro-N-nitrosoguanidine pretreatment. In contrast, the E. coli ada gene on a low-copy-number plasmid was efficiently induced in S. typhimurium, and high methyltransferase activities were observed. We concluded that the inefficient induction of the adaptive response in S. typhimurium results from weak transcriptional activation of its ada gene by the self-methylated protein.

Accumulation of silver by growing and non-growing populations of Citrobacter intermedius B6

Accumulation of silver is reported for growing and non-growing populations of Citrobacter intermedius B6. In non-growing cultures a maximum uptake of 4.35% (w/w) was observed at an initial silver concentration of 2111.2 μmol Ag+ l-1. In contrast the maximum uptake of silver by growing bacteria was 2.81% (w/w) at an effective concentration of silver of 217.8 μmol·l-1. Silver accumulation rates in both resting (460 μmol Ag+ g-1 per hour) and continuously grown (41 μmol Ag+ g-1 per hour) bacteria are higher than previously reported. Cell fractionation and electron microscopy of continuously grown bacteria indicated that accumulation of silver was associated with the cell envelope, in the form of dense deposits of macromolecular proportions. This observation discounts simple surface adsorption as the process of accumulation in growing cultures.

The isolation and characterisation of bacteria capable of accumulating silver

The isolation of silver-resistant, silver-accumulating bacteria is reported. Following the screening of a number of environmental sources, silver-resistant Enterobacteriaceae were isolated from both sewage and photographic processing effluent. The level of resistance to silver and other heavy metals was determined for a selection of these isolates and, together with preliminary accumulation data derived from batch culture studies, one isolate, a strain of Citrobacter intermedius, was selected for further examination. The effect of silver concentration on batch culture growth of this organism was also investigated.

Mutagenic DNA repair genes on plasmids from the ‘pre-antibiotic era’

Resistance transfer factors are natural conjugative plasmids encoding antibiotic resistance. Some also encode mutagenic DNA repair genes giving resistance to DNA damage and induced mutagenesis. It has been shown that antibiotic resistance has been acquired by recent transposition events; however, we show here that mutagenic repair genes existed much earlier on these types of plasmids. Conjugative plasmids from eight incompatibility groups from the Murray collection of 'pre-antibiotic era' enterobacteria were tested for complementation of mutagenic repair-deficient Escherichia coli umuC36. Although none of these plasmids carry transposon-encoded drug resistance genes, IncI1 and IncB plasmids were identified which restored ultraviolet resistance and induced mutability to umuC36 mutants. Furthermore they increased the UV resistance and induced mutability of wild-type E. coli, Klebsiella aerogenes and Citrobacter intermedius, thus showing that they could confer a general selective advantage to a variety of hosts. Like known mutagenic repair genes, complementation by these plasmid genes required the SOS response of the host cell. Nucleotide hybridisation showed that these plasmids harboured sequences similar to the impCAB locus, the mutagenic repair operon of modern-day IncI1 plasmids. The evolution of mutagenic repair genes is discussed.

The activity and reaction specificity of tyrosine phenol-lyase regulated by monovalent cations

This work was aimed at studying the effect of monovalent inorganic cations (Li +, Na +, K +, Rb +, Cs +, NH 4 +) on the catalytic and spectral characteristics of tyrosine phenol-lyase from Citrobacter intermedius. These cations were shown to influence the proportion of the ß-elimination reaction rate to the rate of side transamination reaction. Most of the monovalent cations are non-competitive activators of the ß-elimination reaction; Li + exerts no effect on the enzyme activity in this reaction; Na + is an inhibitor of the ß-elimination reaction. The activation of tyrosine phenol-lyase by monovalent cations stems from the creation of an active holoenzyme form (λ max420 nm) due to conformational rearrangements of the protein molecule.

Crystallization and crystal data on tyrosine phenol-lyase

Crystals of the apoenzyme of tyrosine phenol-lyase (EC 4.1.99.2), a pyridoxal 5′-phosphate-dependent enzyme from Citrobacter intermedius, have been grown by vapor diffusion of an ammonium sulfate solution to a protein solution. The crystals belong to space group P2 12 12, with dimensions of a = 75.5 Å, b = 138.4 Å and c = 94.1 Å and diffract up to 2.7 Å resolution. The asymmetric unit contains one half of the enzyme tetrameric molecule. Two heavy-atom derivatives of the crystals have been obtained.

Transamination catalysed by tyrosine phenol-lyase from Citrobacter intermedius.

The interactions of tyrosine phenol-lyase with its substrates: L-tyrosine and L-serine, and the competitive inhibitors: L-alanine, L-phenylalanine, L-m-tyrosine, were studied. It was demonstrated that the enzyme catalyzed a half-transamination reaction between substrates or inhibitors and the protein-bound pyridoxal phosphate. The products of this side-reaction, pyridoxamine phosphate and the respective keto acids, were identified. The kinetic parameters were determined for beta-elimination of L-tyrosine and of L-serine, and for the transamination of L-serine and the inhibitors used. The transfer of the amino group to the coenzyme takes place in the direction from amino acid to pyridoxal phosphate, but not in the opposite direction, i.e. the transamination is irreversible.

Location of tyrosine phenol-lyase in some Gram-negative bacteria

Citrobacter intermedius, Escherichia coli and Proteus morganii were converted into spheroplasts by adding lysozyme and EDTA to the sucrose medium. The periplasmic enzymes alkaline phosphatase and 5′-nucleotidase were released into the medium during spheroplasting, but the inducible tyrosine phenol-lyase and tryptophanase remained in the spheroplasts, as did the cytoplasmic positional markers glutamate dehydrogenase and glucose-6-phosphate dehydrogenase, indicating that both enzymes are located in the cytoplasm.

ChemInform Abstract: Hydrogen‐gas Production with Citrobacter intermedius and Clostridium pasteurianum.

Chemischer InformationsdienstVolume 13, Issue 37 Other Subjects ChemInform Abstract: Hydrogen-gas Production with Citrobacter intermedius and Clostridium pasteurianum. J. D. BROSSEAU, J. D. BROSSEAUSearch for more papers by this authorJ. E. ZAJIC, J. E. ZAJICSearch for more papers by this author J. D. BROSSEAU, J. D. BROSSEAUSearch for more papers by this authorJ. E. ZAJIC, J. E. ZAJICSearch for more papers by this author First published: September 14, 1982 https://doi.org/10.1002/chin.198237347AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume13, Issue37September 14, 1982 RelatedInformation

Agitation effects on hydrogen gas production by Citrobacter intermedius

Agitation effects on hydrogen gas production by <i>Citrobacter intermedius</i>

The effect of temperature on the growth and hydrogen production by Citrobacter intermedius

Citrobacter intermedius was grown batchwise in a mineral salts medium with glucose as a carbon and energy source under anaerobic conditions and at different temperatures. The effect of temperature on the following parameters was studied: maximum specific growth rate, μ max, maximum rate of hydrogen gas production and maximum rate of total gas (H2 + CO2) production. Arrhenius plots were used to determine the activation energies associated with μ max and maximum rates of hydrogen gas production.