The development of a formulation for radiation-sterilizable urea broth

Urea broth, a medium used for the identification of the genus Proteus, was sterilized by gamma radiation, using radiation doses of 1-1.5 Mrad. The radiation-sterilized medium, modified by adding sodium ascorbate and increasing its phenol red and yeast extract content, performed as well as the commercial formulation prepared aseptically, when tested with different Proteus and non-Proteus species. Gamma-irradiation appears to be an attractive and economical method for sterilizing nutrient media in sealed tubes, avoiding the risk of contamination during processing.     

Diagnostic value of a novel nutrient medium for isolation and cultivation of pathogens causing enteric yersiniosis and pseudotuberculosis

A new nutrient medium for isolation and cultivation of the causative agents of enteric yersiniosis and pseudotuberculosis was found to have advantages over Endo medium in its differentiating and inhibiting properties. This medium permitted the easy differentiation of Yersinia pseudotuberculosis from Y. enterocolitica, as well as from Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, K. rhinoscleromatis, Hafnia, Enterobacter and Citrobacter by color; from Proteus inconstans by swarming. In addition, weakly swarming of P. vulgaris differed by their light bluish color and Pseudomonas aeruginosa, by the brilliance and size of colonies. Endo medium could be used only for differentiation of E. coli from lactose-negative Yersinia colonies, Klebsiella (by mucous growth) and, to a certain extent, all Proteus species (by swarming). The medium under test and the control medium inhibited the growth of Staphylococcus aureus. In contrast to Endo medium, the medium under test partially inhibited the growth of K. rhinoscleromatis and the swarming of P. inconstans. The new medium is now introduced into practice.     

New plate medium for facilitated differentiation of Salmonella spp. from Proteus spp. and other enteric bacteria

A new agar medium for the differentiation of Salmonella spp. from other members of the family Enterobacteriaceae is described. This medium exploits a novel phenotypic characteristic of Salmonella spp.: the formation of acid from propylene glycol. This characteristic may be used in combination with a chromogenic indicator of beta-galactosidase to differentiate Salmonella spp. from Proteus spp. and the other members of the Enterobacteriaceae. Desoxycholate may be included in the plate medium as an inhibitor of gram-positive organisms. Non-typhi Salmonella spp. yield distinct, bright red colonies on this medium, allowing facilitated identification and unambiguous differentiation from Proteus spp.     

New plate medium for facilitated differentiation of Salmonella spp. from Proteus spp. and other enteric bacteria.

A new agar medium for the differentiation of Salmonella spp. from other members of the family Enterobacteriaceae is described. This medium exploits a novel phenotypic characteristic of Salmonella spp.: the formation of acid from propylene glycol. This characteristic may be used in combination with a chromogenic indicator of beta-galactosidase to differentiate Salmonella spp. from Proteus spp. and the other members of the Enterobacteriaceae. Desoxycholate may be included in the plate medium as an inhibitor of gram-positive organisms. Non-typhi Salmonella spp. yield distinct, bright red colonies on this medium, allowing facilitated identification and unambiguous differentiation from Proteus spp.     

Sensitivity of Proteus hauseri bacteria to chemotherapeutic preparations depending on the cultivation conditions and on the composition of the nutrient medium]

Sensitivity of 227 Proteus strains isolated from patients was studied comparatively using the agar-diffusion method (disks) and the method of serial dilutions. Marked differences in the numbers of the strains resistant to benzylpenicillin and chloramphenicol were found with the above methods. It was shown that the ingredients of Ploskirev's medium significantly (by 2.8--13.5 times) inhibited the antibacterial activity of streptomycin, neomycin, monomycin, kanamycin, ampicillin and nalidixic acid and had practically no effect on the activity of benzylpenicillin, chloramphenicol and furazolidone. The values of the MIC of the drugs used in the experiment with liquid media correlated with those obtained with Sabouro's medium, which provided recommendation of the latter for determination of Proteus sensitivity by the method of serial dilutions in the solid medium, Cultivation of Proteus at a temperature of 40 degrees C resulted in a decrease of the resistance to most of the drugs tested by (by 3--12.4 times).     

Effect of the proteolytic enzymes of Bacillus licheniformis and the lysoamidase of Lysobacter sp. XL1 on Proteus vulgaris and Proteus mirabilis

Preparations of culture liquid of three Bacullus licheniformis strains (S, 103, and 60.4) and the enzymatic preparation lysoamidase from culture liquid of Lysobacter sp. strain XL1 actively lysed preliminarily autoclaved cells of gram-negative bacteria Proteus vulgaris and P. mirabilis. Living Proteus cells treated with these enzymatic preparations were lysed during their subsequent autoclaving. Inoculation of enzyme-treated Proteus cells, taken either separately or in combination with one another and polymyxin B, into a rich medium led to cell repair and restoration of viability of culture.     

Antagonistic interrelationships of Bifidobacterium bifidum i Proteus vulgaris in vitro in the digestive tract of gnotobiotic chicks]

The antagonistic relations between Bacterium bifidum, strain I/850 phi, and Proteus vulgaris, strain F-30, were studied. These organisms, when introduced together in equal doses into the digestive tract of gnotobiotic chickens in a single administration, were shown to create certain ecological correlations in various organs with the prevalence of bifidobacteria which exerted no negative influence on Proteus vulgaris. The additional daily administration of bifidobacteria for 3 days running in doses 1000 times as great as the initial dose, the content of both dibifobacteria and Proteus vulgaris in the intestine being at that time at its maximum, resulted in the suppression of the growth of Proteus vulgaris. Our findings indicate that the influence of the pH of the medium should be considered in order to obtain the evidence of significantly pronounced antagonistic relations between the two organisms in vitro.     

Effects of Related Anionic Detergents on Flagellation, Motility, Swarming, and Growth of Proteus

The effects of a series of sodium alkyl sulfates (C(4) to C(16)) on flagellation, motility, swarming, and growth of Proteus were examined. The concentrations of the various sodium alkyl sulfates completely inhibiting the swarming phenomenon (on solid medium) and motility (in liquid medium) were in the same order of magnitude. The inhibiting effect of the detergents examined increased from sodium hexyl sulfate (inhibitory concentration, 20 to 30 mmoles per liter) to sodium tetradecyl sulfate (inhibitory concentration, 0.1 to 0.5 mmoles per liter). Flagella were produced neither in liquid nor on solid medium at these concentrations as could be observed by electron microscopy. At concentrations where motility was not impaired, intact flagellation could be observed. At a concentration of 0.1 mmole per liter, sodium tetradecyl sulfate completely inhibited the motility of Proteus in the liquid medium employed without impairing growth.     

Molecular Nature of the Deoxyribonucleic Acid of a Thermosensitive R Factor, Rts1

The deoxyribonucleic acid of the thermosensitive R factor, Rts1, has been examined by the technique of sedimentation in alkaline sucrose, electron microscopy, and radiation target size. All these methods yielded a molecular weight of approximately 120 million for Rts1 deoxyribonucleic acid in Escherichia coli. Sedimentation analysis revealed that Rts1 deoxyribonucleic acid in Proteus mirabilis was also 120 million daltons. Rts1 did not segregate into E. coli minicells under the conditions where another smaller non-thermosensitive R factor could.     

产胞外黑色素菌株的筛选*

对不同来源获得的47株菌株在酪素培养基上生长、产色素情况进行了对比研究。从中选取了T4和Neurospora crassa AS3．1602,比较了二利用5种不同培养基产黑色素的能力。对T4菌株产生的黑色素做了初步研究,并初步鉴定T4菌株为奇异变形杆菌(Proteus mirabilis）。     

Development of an improved medium for the isolation of 'Haemophilus somnus'

A medium containing lincomycin (3 μg/ml), cycloheximide (100 μg/ml) and chloral hydrate (0–1 %) was superior to all others examined for the isolation of 'Haemophilus somnus' from material contaminated with Proteus species.     

Effect of immunization on the radioresistance of mice to the action of 90Sr]

The preliminary immunization with heated Proteus vulgaris culture introduced in a single injection was found to have a positive influence on the resistance of white mice to radiation emitted by incorporated 90Sr. This effect was manifested by an increase in the survival rate and the mean survival time of the animals, as well as by their increased physical endurance, and the stimulation of recovery process in the spleen.     

The expression of a highly expressed Bacillus subtilis gene is not reduced by introduction of multiple codons normally not present in such genes

A recombinant DNA Proteus mirabilis L-form expression system, LVI (pJS127), was used to synthesize human fusion interferon alpha 1 (f-IFN-alpha 1). In the expression plasmid used, the complete coding sequence of IFN-alpha 1 was linked to the streptococcal speA promoter and the 5' end of the speA structural gene including its signal sequence coding region. LVI (pJS127) was capable of complete secretion into the culture medium of biologically active f-IFN-alpha 1 whose identity was confirmed by immunological and chemical evidence. In particular, bacterial L-forms were for the first time shown to be capable of correct signal peptide processing, as determined by N-terminal sequencing of the secreted f-IFN.     

Inhibition of Swarming in Proteus spp. by Tannic Acid

Swarming in all 27 strains of Proteus spp. tested was inhibited by the presence of 0.02% (w/v) tannic acid in the nutrient medium. Cells from colonies on this medium were nearly all short forms but were motile and piliated. The swarm-inhibition effect was not reversed by the addition of calcium chloride. The growth of other bacterial species was inhibited to varying extents by tannic acid: Gram positive cocci ( Micrococcus, Sarcina , and Staphylococcus spp.) were particularly sensitive. The relative resistance of Gram negative bacteria and the swarm-inhibition of Proteus spp. could be due to binding of tannic acid to proteins in the outer membrane of the cell wall.     

The Use of Sulphamezathine for Inhibiting Proteus Spp. on Baird-Parker's Isolation Medium for Staphylococcus aureus

S ummary : The addition of 50 μg of sulphamezathine/ml to egg-tellurite-glycine-pyruvate agar was effective in suppressing the growth and swarming of Proteus spp. Small numbers of Staphylococcus aureus (10³/g) could be recovered quantitatively on the modified medium in the presence of up to 10⁶/g of mixed Proteus vulgaris and Proteus mirabilis strains.     

Growth inhibition of Proteus mirabilis by cyclic adenosine 3''-5''-monophosphate.

Growth of Proteus mirabilis on a synthetic agar medium containing either glycerol, galactose, or trehalose as the sole source is inhibited by 5 mM cyclic adenosine 3',5'-monophosphate (cAMP). Inhibition on an agar medium is evident as loss of viability, but in broth cAMP only slightly inhibits growth rate. Inhibition is associated with the accumulation of methylglyoxal in the medium. A nonswarming mutant of P. mirabilis is not inhibited by cAMP on either of the three carbon sources, but it is sensitive to exogenous methylglyoxal.     

Siderophore production by Proteus mirabilis

Studies on the isolation and characterization of Proteus mirabilis siderophores provided no evidence that these bacteria synthesize catechol- or hydroxamate-type siderophores. However, gas chromatograph analysis in conjunction with mass spectroscopy revealed the presence of alpha-hydroxyisovaleric acid, a previously unknown metabolite. Additional substantiating evidence for the presence of alpha-hydroxyisovaleric acid in these bacteria was obtained from experiments involving the use of thin-layer chromatography and an ultraviolet absorption spectrum. This compound was found to be capable of removing iron from the synthetic chelator, ethylene-diamine-di-orthohydroxyphenyl acetic acid, and supplying that iron to the bacteria both in a solid agar medium and in a liquid medium. Proteus mirabilis was found to possess an enzyme capable of catalyzing the reaction by which alpha-hydroxyisovaleric acid is converted to alpha-ketoisovaleric acid, an intermediate in the valine biosynthetic pathway.     

Some properties of cefoxitin-induced spheroplasts of Proteus species, including sensitivity to colistin

Spheroplasts of various Proteus species could be induced by cefoxitin in nutrient broth alone or in broth containing 0–33 mol/l sucrose and 4 times 10^-3 mol/l magnesium sulphate. Spheroplasts induced in the latter medium were lysed when diluted into water, but osmotically stable if transferred to broth or other appropriate menstrua. High concentrations of colistin were needed to induce lysis of cefoxitin-induced spheroplasts and it was concluded that, contrary to earlier findings with benzylpenicillin-induced spheroplasts, peptidoglycan had little, if any, role to play in acting as a barrier to the entry of polymyxins into Proteus cells.     

Effect of chlorhexidine/EDTA/Tris against bacterial isolates from clinical specimens

Chlorhexidine/EDTA/Tris was more active compared with chlorhexidine against the following species of organisms: Acinetobacter species, Citrobacter species, Enterobacter species, Escherichia coli, Proteus mirabilis, Providence species, Pseudomonas species, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus faecalis, when tested in isosensitest agar. The addition of 20% serum to the medium reduced its effectiveness mainly against Providence species, Proteus species, and Streptococcus faecalis. However, the potential for this solution as a bladder instillation or topical antiseptic should be considered because of its reduced side effects compared with chlorhexidine alone, and its increased general effectiveness against all isolates tested.     

Trimethylamine oxide: a terminal electron acceptor in anaerobic respiration of bacteria.

Trimethylamine oxide (TMAO) stimulated both the anaerobic growth rate and the growth yield of Proteus NTHC 153. The molar growth yield from glucose and pyruvate in tryptone/yeast extract medium doubled in the presence of TMAO, and the organism grew anaerobically on the non-fermentable substrates L-lactate and formate when TMAO was added to the medium. We conclude that TMAO stimulated growth by serving as a terminal electron acceptor in an oxidative phosphorylation process.