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PubMed1969

Interacting factors that influence long-term storage of live Pasteurella tularensis vaccine and Rift Valley fever virus.

Studies were conducted on the interaction of various parameters which affect the storage stability and growth potential of liquid cultures of Pasteurella tularensis live vaccine strain (LVS) and Rift Valley fever virus Van Wyk strain (RVFV). Storage variables studied with LVS included four storage temperatures (4, -20, -65, -175 C), single and multiple freeze-thaw cycles, two freezing and two thawing rates (slow and fast), various inoculum levels (1, 3, 5, and 10%) for the determination of growth potential, and the retention of immunizing potential (mice and guinea pig) after storage. Neither the freezing rate nor the number of freeze-thaw cycles seriously affected the growth of LVS after storage at -175C; however, the slow rate of thaw proved deleterious as were all temperatures of storage except -175 C after 1 year of storage, as shown by both criteria of evaluation. RVFV produced in two combinations of cell lines and media (LM cell line-199 peptone medium and LDR cell line-Eagle's minimum essential medium) was stored at three serum levels (10, 20, 40%), three pH values (6.2., 7.0, 7.8), and three temperatures (-20, -65, -175 C). These studies indicated: (i) virus produced in the LDR cell line and Eagle's medium was more stable than that produced in the LM cell line and 199 peptone medium for either short- or long-term storage; (ii) serum levels did not affect stability; and (iii) low pH resulted in losses during long-term storage under all conditions tested. Thus, cryogenic storage is advantageous for stock culture maintenance of bacteria and viruses and for other similar applications.

Animals↗
PubMed1969

Role of alcoholic intermediates in formation of isomeric ketones from n-hexadecane by a soil Arthrobacter.

A soil Arthrobacter species isolated from an Oregon soil was capable of transforming n-hexadecane to a series of ketonic products, the 2-,3-, and 4-hexadecanones, with evidence for accumulation of 2- and 3-hexadecanols as oxidative intermediates when yeast extract or peptone was used as a growth substrate. The accumulation and participation of internal alcohols in this type of hydrocarbon transformation has not been previously reported. In the absence of yeast extract or peptone, growth from low-level inocula was not observed when n-hexadecane or two oxidation products, 2-hexadecanol and 3-hexadecanone, were used as substrates. However, washed resting cell suspensions of the organism transformed 2-hexadecanol, or a mixture of 2-,3-, and 4-hexadecanols, to the corresponding ketones without lag, indicating the possible constitutive nature of the alcohol dehydrogenase enzyme(s) carrying out this reaction. The addition of glucose to these resting cells stimulated transformation of n-hexadecane to alcoholic and ketonic oxidation products. Formation of isomeric internal alcohols appears to be a limiting step in ketone formation by this Arthrobacter isolate.

Alcohols↗
PubMed1972

Characterization of the repair of injury induced by freezing Salmonella anatum.

Fast freezing and slow thawing of Salmonella anatum cells suspended in water resulted in injury of more than 90% of the cells that survived the treatment. The injured cells failed to form colonies on the selective medium (xyloselysine-peptone-agar with 0.2% sodium deoxycholate) but did form colonies on a nonselective (xylose-lysine-peptone-agar) plating medium. In Tryptic soy plus 0.3% yeast extract broth or minimal broth, most of the injured cells repaired within 1 to 2 hr at 25 C. Tryptic soy plus yeast extract broth supported repair to a greater extent than minimal broth. Phosphate or citrate at concentrations found in minimal broth supported repair of some cells. MgSO(4), when present with inorganic phosphate or citrate or both, increased the extent of repair. The repair process in the presence of phosphate was not prevented by actinomycin D, chloramphenicol, and D-cycloserine, but was prevented by cyanide and 2,4-dinitrophenol (only at pH 6). This suggested that the repair process might involve energy metabolism in the form of adenosine triphosphate. The freeze-injured cells were highly sensitive to lysozyme, whereas unfrozen fresh cells were not. In the presence of phosphate or minimal broth this sensitivity was greatly reduced. This suggested that, at least in some of the cells, the injury involved the lipopolysaccharide of the cell wall and adenosine triphosphate synthesis was required for repair.

Adenosine Triphosphate↗
PubMed1973

Influence of milk components on the injury, repair of injury, and death of Salmonella anatum cells subjected to freezing and thawing.

Fast freezing and slow thawing Salmonella anatum cells in various milk components inactivated from 20 to 98% of the cells and damaged 40 to 90% of the cells surviving the treatments. Injured cells failed to form colonies on a selective medium (xylose-lysine-peptone agar with 0.2% sodium deoxycholate) but did form colonies on a nonselective plating medium (xylose-lysine-peptone agar). The major milk components-lactose, milk salts, casein, and whey proteins-influenced the extent of injury, repair of injury, and death. The percentages of cells injured and inactivated were decreased by the presence of any milk components except whey proteins. Also, repair of injury was promoted by the presence of each milk component except whey proteins, which in contrast inhibited repair. Phosphate was the most influential milk salts component that protected the cells and promoted repair of injury. These individual milk components may have decreased the extent of freezing-induced death and cellular damage by stabilizing the S. anatum cell envelope.

Animals↗
PubMed1985

Macrophage-related fibrinolysis in experimental disseminated histoplasmosis.

A model of disseminated histoplasmosis in CBA/J mice was developed. Cultures of Histoplasma capsulatum from the spleens of infected mice suggested almost complete clearance of fungi by week 3. The adherent spleen cells from infected mice showed a 2- to 20-fold increase in fibrinolysis. The increase in activity was maximal around 1 to 2 weeks and disappeared after week 3 of infection, and this paralleled the progressively decreasing number of culturable fungi from the spleen. In vitro coculture of infected spleen cells or nylon wool-purified immune T cells and proteose peptone-induced macrophages resulted in increased fibrinolysis. Peritoneal exudate cells from infected mice also showed increased fibrinolysis. The addition of soluble antigen to an in vitro culture system resulted not only in an increase in fibrinolytic activity of peritoneal exudate cells derived from infected mice but also of proteose peptone-induced macrophages. These observations suggest that spleen and peritoneal macrophages from H. capsulatum-infected mice exhibit increased fibrinolysis which in turn is indicative of macrophage activation. The mechanism of activation occurs as a result of immunologically specific T cell-macrophage interaction and by the action of histoplasma products on the macrophages. The significance of these findings and the role of the plasminogen activator assay in studies of disseminated fungal infection are discussed.

Animals↗
PubMed1996

Induction of an extracellular esterase from Candida albicans and some of its properties.

An extracellular esterase from Candida albicans A-714 was found to be induced in a medium containing 0.7% yeast nitrogen base and 2.5% Tween 80 (polyoxyethylenesorbitan compounds). Enzyme activity, which exists predominantly in the extracellular space, was measured by a colorimetric method using alpha-naphthyl palmitate as a substrate. The induction level of the esterase activity was found to be well correlated with fungal growth and was dependent on the Tween 80 concentration. Such esterase activity was observed only in medium containing Tween 80 or other Tweens as the sole carbon source and therefore was not observed in either peptone-glucose medium or peptone-glucose medium supplemented with Tween 80. The induced esterase was heat labile and had maximum activity at pH 5.5. Enzyme activity was stimulated by the addition of sodium taurocholate, an activator of lipase. Thin-layer chromatography revealed that this enzyme does not hydrolyze triolein and L-alpha-lecithin, suggesting that it is a monoester hydrolase (not a lipase in the strict sense of the word). Esterase activity was examined in 85 clinical isolates of Candida species; C. albicans, C. tropicalis, and C. parapsilosis tended to have higher enzyme activities than C. kefyr, C. krusei, C. glabrata, and C. guilliermondii. Although the physiological properties of this esterase are not clear at present, it was found to be crucial for fungal growth under specific conditions.

Candida albicans↗
PubMed2000

Host and bacterial factors involved in the innate ability of mouse macrophages to eliminate internalized unopsonized Escherichia coli.

In an effort to better understand genetic and cellular factors that influence innate immunity, we examined host and bacterial factors involved in the nonopsonic phagocytosis and killing of Escherichia coli K-12 by mouse macrophages. Unelicited (resident) peritoneal macrophages from five different mouse strains, BALB/c, C57BL/6, CD-1, C3H/HeJ, and C3H/HeN, were employed. Additional macrophage populations were obtained from CD-1 mice (bone marrow-derived macrophages). Also, for BALB/c and C57BL/6 mice, peritoneal macrophages elicited with either thioglycolate or proteose peptone, bone marrow-derived macrophages, and macrophage-like cell lines derived from the two strains were employed. Two E. coli K-12 strains that differed specifically in their abilities to produce type 1 pili containing the adhesive protein FimH were examined. The parameters used to assess macrophage bacteriocidal activity were (i) the killing of internalized (gentamicin-protected) E. coli during the approximately 4-h assay and (ii) the initial rate at which internalized E. coli were eliminated. Data on these parameters allowed the following conclusions: (i) unelicited or proteose peptone-elicited peritoneal macrophages were significantly better at eliminating internalized bacteria than thioglycolate-elicited peritoneal macrophages, bone marrow-derived macrophages, or macrophage cell lines; (ii) the host genetic background had no significant effect upon the ability of unelicited peritoneal macrophages to kill E. coli (even though the mouse strains differ widely in their in vivo susceptibilities to bacterial infection); and (iii) the FimH phenotype had no significant effect upon E. coli survival once the bacterium was inside a macrophage. Additionally, there was no correlation between the bacteriocidal effectiveness of a macrophage population and the number of bacteria bound per macrophage. However, macrophage populations that were the least bacteriocidal tended to bind higher ratios of FimH(+) to FimH(-) E. coli. The effect of gamma interferon, fetal calf serum, and the recombination proficiency of E. coli were examined as factors predicted to influence intracellular bacterial killing. These had no effect upon the rate of E. coli elimination by unelicited peritoneal macrophages.

Adhesins, Bacterial↗
PubMed1969

Cholera toxins: immunogenicity of the rabbit ileal loop toxin and related antigens.

A method of assay of immunogenic potency of the cholera gut toxin is described; it is based on the relation of dose of antigen to neutralizing antibody titer produced in the rabbit under defined conditions and allows quantification of immunogenicity as immunogenic units per milligram of protein. Evidence, based on immunogenicity and rabbit ileal loop toxicity, is presented which indicates that the positively charged fraction of liquid-culture supernatant fluid eluted in deionized water from diethylaminoethyl Sephadex, or in electrolyte from carboxymethyl Sephadex, is a complex made up of a nonantigenic toxic moiety, a nontoxic protein component which elicits the formation of toxin-neutralizing antibody, and an inactive fraction. The complex may also be dissociated in high-salt concentrations with apparent recombination of the toxic moiety with a nondialyzable constituent of peptone to give a negatively charged complex. The immunogenic component is found in nontoxic supernatant fluids of cultures grown at pH 6.5 or in media deficient in peptone. It is also present in the nontoxic fraction eluted from diethylaminoethyl Sephadex in electrolyte or in deionized water from carboxymethyl Sephadex. When separated from the positively charged toxic moiety, the net charge of the antigen is reduced as shown by immunoelectrophoresis. On primary fractionation, the antigen may be associated with a minor antigenic component of the negatively charged complex containing a major antigen eliciting vibriocidal antibody formation, but antisera to the toxin antigen preparations, either in this form or freed of antigenic contamination by recycling, do not contain vibriocidal antibody. It is suggested that this antigen be designated the T (toxin) antigen, and the antigen producing vibriocidal antibody the V antigen. These two antigens would appear to represent the major antigenic specificities associated with the antitoxic and antibacterial elements of the immune response to infection.

Animals↗
PubMed1971

Production and repair of radiochemical damage in Escherichia coli deoxyribonucleic acid; its modification by culture conditions and relation to survival.

Late log-phase Escherichia coli B/r cells are 1.6 times more sensitive to killing by X rays than are stationary-phase cells when grown in Brain Heart Infusion (BHI) + glucose. The number of single-chain breaks formed per krad is the same for log- and stationary-phase cells. Stationary-phase cells show a somewhat greater ability to repair single-chain breaks (especially after high doses of X rays) than do log-phase cells. The rapidity and extent of postirradiation deoxyribonucleic acid (DNA) degradation are greater in log-phase cells than in stationary-phase cells. The enhanced viability exhibited by stationary-phase cells thus appears to correlate both with enhanced single-chain break repair and the reduced degradation of DNA. Cells grown to stationary phase in peptone medium (PO cells) are 3.4 times more sensitive to killing by X rays than cells grown to stationary phase in peptone medium supplemented with glucose and phosphate buffer (PG cells). The yield of single-strand breaks is the same for both types of cells (but the absolute yield is about two times higher than in the cells grown in BHI + glucose). The kinetics for the repair of single-chain breaks are the same for both types of cells for about 30 min. After this time period, further repair ceases in the PO cells but continues in the PG cells, provided that glucose is present in the medium. Postirradiation DNA degradation is both more rapid and more extensive in PO cells than in PG cells whether or not glucose is present in the postirradiation incubation medium. The survival of stationary-phase E. coli B/r grown in PO or PG medium is likewise unaffected by the presence of glucose in the plating medium, and thus correlates better with the lower DNA degradation seen in the PG cells than with the increased strand rejoining, since this latter process requires the presence of glucose.

Carbon Isotopes↗
PubMed1975

Sporulation in D-glucosamine auxotrophs of Saccharomyces cerevisiae: meiosis with defective ascospore wall formation.

Mutants that require exogenous D-glucosamine for growth were isolated from Saccharomyces cerevisiae X2180-1A after ethyl methane sulfonate mutagenesis. Class A auxotrophs fail to grow on yeast extract-peptone-dextrose and minimal media, whereas class B auxotrophs grow on minimal medium and readily revert to grow on yeast extract-peptone-dextrose medium. Class B auxotrophs are suppressible by a class of suppressors distinct from nonsense suppressors, and their properties suggest that they are defective in a regulatory function. All 23 mutants studied were recessive and allelic, and they define a new gene designated gcn1. An analysis of a class A auxotroph revealed that it lacked L-glutamine:D-fructose 6-phosphate amidotransferase (EC 2.6.1.16) activity and indicates that GCN1 codes the amino acid sequence of this enzyme. The finding that all mutants were allelic indicates that the amidotransferase is the only enzyme responsible for D-glucosamine synthesis in S. cerevisiae. The occurrence of allelic complementation and media-conditional mutants suggests that the amidotransferase is a multimeric enzyme with an activity subject to metabolic control. Diploids homozygous for gcn1 fail to complete sporulation. They proceed through meiosis normally, as judged by the occurrence of meiotic recombination, the production of haploid nuclei, and the formation of multinucleate cells visible after Giemsa staining. However, the formation of glusulase-resistant ascospores is blocked, and deformed spores lacking the electron-dense outer layer characteristic of the normal spore wall are observed by electron microscopy. Cells that acquire the ability to synthesize D-glucosamine, because of gene conversion during meiosis, complete sporulation in a normal fashion. Thus, the GCN1 gene product appears to be synthesized late in sporulation and may prove to be a useful developmental landmark for the termination of ascospore development.

Alleles↗
PubMed1980

Glyoxylate cycle in Mucor racemosus.

The dimorphic phycomycete Mucor racemosus was grown in media containing acetate, glutamate, and peptone as carbon sources. The component enzymes of the glyoxylate bypass, isocitrate lyase and malate synthase, were present under these conditions throughout the growth cycles. Highest specific activities for each enzyme were found in media with acetate as the carbon source. In an enriched peptone medium containing glucose, neither activity was detected until glucose was exhausted from the medium. Treatment of acetate-grown cells with glucose resulted in a rapid decline in the specific activities of both enzymes. The importance of this cycle in acetate-grown cells was indicated by the ability of itaconic acid (100 mM) to inhibit the growth of M. racemosus in acetate but not glutamate media. Itaconate was also shown to be a potent inhibitor of isocitrate lyase activity in vitro.

Acetates↗
PubMed1961

Some factors which affect the initiation of growth of Cryptococcus neoformans.

Howard, Dexter H. (University of California, Los Angeles). Some factors which affect the initiation of growth of Cryptococcus neoformans. J. Bacteriol. 82:430-435. 1961.-The observation that a strain of Cryptococcus neoformans failed to grow in a medium containing normal human serum led to an investigation of some of the physiological factors controlling initiation of growth by this fungus. The data presented show that the growth of C. neoformans is markedly inhibited in media with initial pH values slightly above neutrality. The growth of four strains of the fungus was completely suppressed in peptone broth at pH values above 8. The growth of two strains was partially inhibited at a pH of 7.3. Two other strains grew well at 7.3, but were partially inhibited at pH 7.5. The growth in media at pH values which partially inhibited multiplication was granular in appearance. Microscopically the granules were composed of clumps of yeast cells. The possibility is suggested that pH may exert a portion of its effect on the growth of C. neoformans by influencing those factors which affect the stability of the cells in suspension. At a temperature of 25 C, growth of the fungus was initiated in media with a pH which suppressed growth at a temperature of 37 C. Under the experimental conditions employed in these studies, proteose peptone no. 3 (Difco) serves as both a carbon and a nitrogen source. However, glucose, which is assimilated by C. neoformans in contrast to lactose, permitted the growth of the fungus at pH values which suppressed growth in the absence of the sugar. Since weakly buffered media, containing filtered, normal human serum, have an alkaline reaction higher than that shown to suppress the growth of C. neoformans, it was concluded that this factor was primarily responsible for the failure of the fungus to reproduce in tissue culture media. However, it is also possible to show that even under optimal pH conditions normal human serum exerts an anticryptococcal effect. This activity of human serum was relatively heat-stable and was expressed only in high concentrations of serum. Serum adsorbed with viable cells of C. neoformans also inhibited the growth of the fungus, but a partially purified globulin fraction of serum was not inhibitory. The data are discussed in relation to the work of other investigators.

Cryptococcus↗
PubMed1961

Factors affecting the elaboration by Clostridium histolyticum of proteinases capable of debriding third degree burn eschars on guinea pigs.

Berman, Sanford (Walter Reed Army Institute of Research, Washington, D. C.), Joseph P. Lowenthal, Marion E. Webster, Patricia L. Altieri, and Raymond B. Gochenour. Factors affecting the elaboration by Clostridium histolyticum of proteinases capable of debriding third degree burn eschars on guinea pigs. J. Bacteriol. 82:582-588. 1961.-A comparison of three strains of Clostridium histolyticum grown in two different media indicated that the H-4 strain produced the greatest yield of enzyme(s) capable of debriding third degree burn eschars on guinea pigs. Some of the nutritional and physiological factors affecting the elaboration of enzymes by this strain have been investigated. Maximal yields have been obtained after incubation for 14 to 16 hr at 30 C in a medium consisting of 5% proteose-peptone, 1.5% trypticase soy broth, and vitamins; pH 7.5. A medium consisting of 2% proteose-peptone and 2% Casamino acids yields somewhat lower enzyme titers, but has the compensating advantage of being less costly and may be more amenable to purification and concentration procedures because of its reduced precipitable nitrogen content.

Amino Acids↗
PubMed1963

Respiratory systems in the hemin-requiring Haemophilus species.

White, D. C. (Rockefeller Institute, New York, N.Y.). Respiratory systems in hemin-requiring Haemophilus species. J. Bacteriol. 85:84-96. 1963.-If grown in Levinthal's medium or in proteose peptone medium with excess hemin, Haemophilus influenzae, H. aegyptius, and H. canis (H. haemoglobinophilus) form an electron-transport system consisting of six cytochromes and two respiratory flavoproteins. In proteose peptone, these species can greatly modify the composition of their electron-transport complex. With anaerobic incubation in the presence of nitrate, they produce increased amounts of cytochrome c(1) and the cytochrome oxidases a(1) and o. This anaerobic pattern is greatly exaggerated by growth under carbon monoxide, in which case large concentrations of cytochrome oxidase are produced. In the presence of the inhibitor secobarbital or of growth-limiting amounts of hemin, intermediate amounts of cytochromes and respiratory flavoproteins are formed. When only small amounts of hemin are present, these species grow but form no detectable cytochrome system. Catalase is the only hemoprotein found. Under these conditions, the addition of glucose induces the formation of a lactate oxidase flavoprotein if the system is incubated aerobically. This cytochromeless state also occurs when these species are grown in KCN or anaerobically without nitrate and with excess hemin. The ability of these species to modify the composition of the electron-transport system strongly suggests that this function unit is formed from individual components. Hemin-requiring Haemophilus species have a hemin-sparing compensatory mechanism that allows growth under conditions under which hemin-independent Haemophilus species will not grow.

Catalase↗
PubMed1968

Thiamine-induced formation of the monopyrrole moiety of prodigiosin.

Thiamine stimulates the production of a red pigment, which is chromatographically and spectrophotometrically identical to prodigiosin, by growing cultures of Serratia marcescens mutant 9-3-3. This mutant is blocked in the formation of 2-methyl-3-amylpyrrole (MAP), the monopyrrole moiety of prodigiosin, but accumulates 4-methoxy-2,2,'-bipyrrole-5-carboxaldehyde (MBC) and can couple this compound with MAP to form prodigiosin. Addition of thiamine caused production of MAP, and as little as 0.02 mg of thiamine per ml in a peptone-glycerol medium stimulated production of measurable amounts of prodigiosin. Phosphate salts and another type of peptone decreased the thiamine-induced formation of prodigiosin; yeast extract and glycerol enhanced the formation of this substance. Thiamine also enhanced production of prodigiosin by wild-type strain Nima of S. marcescens. The thiamine antagonists, oxythiamine and pyrithiamine, inhibited thiamine-induced production of MAP and of prodigiosin by the mutant strain 9-3-3, formation of prodigiosin by the wild-type strain Nima, and production of MAP by another mutant, strain WF. The pyrimidine moiety of thiamine was only 10% as effective as the vitamin; the thiazole moiety, only 4%; and the two moieties together, 25%. Various other vitamins tested did not stimulate formation of prodigiosin by strain 9-3-3. Thiamine did not stimulate production of prodigiosin by a single-step mutant that showed the same phenotypic block in prodigiosin biosynthesis as strain 9-3-3. This is not surprising since strain 9-3-3 originated as a result of two mutational events. One event may involve thiamine directly, and the other may involve the biosynthesis of MAP. Thiamine is probably involved in the regulation of the biosynthesis of MAP, because the vitamin or inhibitory antagonists must be added during the early phases of growth in order to be effective.

Anti-Bacterial Agents↗
PubMed1969

Effects of oleate starvation in a fatty acid auxotroph of Escherichia coli K-12.

The effects of oleate starvation on an oleate auxotroph of Escherichia coli K-12 were investigated. Following removal of oleate from the mutant growing in a minimal glycerol-peptone medium, the cells stopped making deoxyribonucleic acid, ribonucleic acid, protein, and phospholipids; they began to die exponentially and finally lysed. During oleate starvation in minimal medium minus peptone, inhibition of macromolecular syntheses and death occurred; however, lysis did not follow. When growth ceased, no further dying was observed. It is shown that none of the early effects (inhibition of macromolecular syntheses and death) can be due to leakiness of the cells, induction of a prophage or a colicin, or lack of energy sources. The cause of inhibition of macromolecular syntheses remained unknown. Since the rate of death was the same as the generation time under different conditions, it appears that death is due to the defective synthesis of some cellular structure (quite possibly, cytoplasmic membrane) during phospholipid deficiency. Lysis was found to require protein synthesis; electron microscopy revealed a peculiar type of "lysis from within"; i.e., the shape of the cells did not change but fragmentation of the inner layer of the cell envelope occurred. The murein was found to be unaltered. Most likely, lysis was a consequence of the cell's attempt to synthesize cytoplasmic membrane with altered phospholipid composition or during phospholipid deficiency. Several membrane functions (respiration, adenosine triphosphate formation, permeability) existing before oleate removal were not lost during starvation. Therefore, general damage to the membrane did not occur, and it could be that most, if not all, described effects were due to defective de novo membrane synthesis.

Adenosine Triphosphate↗
PubMed1981

Evaluation of transport and storage techniques for isolation of Campylobacter fetus subsp. jejuni from turkey cecal specimens.

Immediate culturing of fecal specimens is not always possible, and appropriate methods for transport and storage of Campylobacter fetus subsp. jejuni specimens have not been fully evaluated. Using nine techniques, we studied the survival of C. fetus subsp. jejuni in cecal specimens from infected turkeys. The organisms survived in specimens held without transport medium for 3 to 15 days (median, 9 days) at 4 degrees C, and 2 to 9 days (median, 4 days) at 25 degrees C. Only 20% of specimens frozen for 24 h at either -20 or -70 degrees C yielded C. fetus subsp. jejuni. Specimens dried on filter paper strips were negative for C. fetus subsp. jejuni within 1.5 h. Cary-Blair medium with decreased agar was the best of the six transport media tested, it enabled recovery of the organism from 100% (3 days) and 71% (7 days) of cecal samples held at 4 degrees C and 94% (3 days) and 85% (7 days) of cecal specimens held at 25 degrees C. In contrast, more than half of all cecal specimens held at 4 or 25 degrees C in Culturettes or buffered glycerol saline were negative by 3 days, and all were negative at 7 days. Results with the other three media studied (Campy-thio, thioglycolate medium, and alkaline peptone water) were intermediate. Overnight incubation of specimens in alkaline peptone water at 37 or 42 degrees C did not enhance recovery of C. fetus subsp. jejuni. Therefore, refrigeration without a transport medium is satisfactory for up to 3 days for recovery of C. fetus subsp. jejuni from specimens, however, we recommend the use of Cary-Blair medium with decreased agar for specimens that must be transported or stored for longer than 3 days and for rectal swabs, to prevent drying.

Animals↗
PubMed1983

Evaluation of differential and selective media for isolation of Aeromonas and Plesiomonas spp. from human feces.

We studied nine solid and two liquid media for their suitability to select Aeromonas and Plesiomonas spp. from human stools, using artificially contaminated samples as well as 254 samples from outpatients with and without diarrhea. Media with optimal sensitivity and specificity for Aeromonas spp. were alkaline peptone-water, Trypticase soy broth with ampicillin, inositol-brilliant green-bile salts agar, dextrin-fuchsin-sulfite agar, xylose-sodium desoxycholate-citrate agar, and Pril-xylose-ampicillin agar. For Plesiomonas sp., alkaline peptone-water and inositol-brilliant green-bile salts agar were optimal. Four strains of Aeromonas spp. were detected in patient samples with these media.

Aeromonas↗