Surface properties of Vibrio vulnificus.

AIMS: Vibrio vulnificus adheres to a diverse range of surfaces, ranging from the chitinous exoskeleton of mollusks to human tissue. To determine whether environmental and human clinical isolates exhibit different adhesion traits, we studied the ability of 10 environmental isolates and 10 clinical isolates to adhere to human epithelial cells and hydrocarbons with log P values ranging from 3.1 to 8.2. METHODS AND RESULTS: All isolates adhered to varying levels to epithelial cells, and were inhibited to various extents from adherence by mannose and fructose. There was a lack of correlation between adherence to either hydrocarbons or cells and colony opacity. Adherence to hydrocarbons was optimal for solvents with a log P < 8.2. CONCLUSIONS: Vibrio vulnificus clinical and environmental isolates exhibit differential adherence to epithelial cells and hydrocarbons. SIGNIFICANCE AND IMPACT OF THE STUDY: The differential adherence of organisms to hydrocarbons based on log P may have utility in drug design and enhancement of food safety.

Dehydroepiandosterone induction of increased resistance to vancomycin in Staphylococcus aureus clinical isolates (MSSA, MRSA).

AIMS: To investigate whether dehydroepiandosterone (DHEA), an androgen present throughout life, alters the response of Staphylococcus aureus clinical isolates to vancomycin. METHODS AND RESULTS: DHEA in physiologically relevant concentrations (0.1, 0.5, 1.0 and 5.0 micromol l(-1)) was tested for its effect on methicillin-sensitive S. aureus (MSSA, n = 53) and methicillin-resistant S. aureus (MRSA, n = 73) response to vancomycin using standard protocols. Mutant selection was determined by serial transfer of selected isolates (n = 5). DHEA-mediated at least a fourfold increase in vancomycin MIC for 42% of MSSA and 21% of MRSA. For five of the isolates (0.1 and 0.5 micromol l(-1) DHEA) the MIC was increased to levels (8 microg ml(-1)) defined as vancomycin-intermediate resistance. CONCLUSION: Resistance was detected only in the presence of DHEA, and was not related to altered generation time, indicating induction of phenotypic resistance. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings require further investigation to determine what role DHEA plays in clinical vancomycin treatment failure that has been reported in the absence of vancomycin genotypic resistance or heteroresistance.

Adjunctive osteopathic manipulative treatment in women with depression: a pilot study.

The authors assessed the impact of osteopathic manipulative treatment (OMT) as an adjunct to standard psychiatric treatment of women with depression. Premenopausal women with newly diagnosed depression were randomly assigned to either control (osteopathic structural examination only; n = 9) or treatment group (OMT; n = 8). Both groups received conventional therapy consisting of the antidepressant paroxetine (Paxil) hydrochloride plus weekly psychotherapy for 8 weeks. Attending psychiatrists and psychologists were blinded to group assignments. No significant differences existed between groups for age or severity of disease. After 8 weeks, 100% of the OMT treatment group and 33% of the control group tested normal by psychometric evaluation. No significant differences or trends were observed between groups in levels of cytokine production (IL-1, IL-10, IL-2, IL-4, and IL-6) or in levels of anti-HSV-1, anti-HSV-2, and anti-EBV antibody. There was no pattern to the osteopathic manipulative structural dysfunctions recorded. The findings of this pilot study indicate that OMT may be a useful adjunctive treatment for alleviating depression in women.

Effect of Sub-MICs of antibiotics on the hydrophobicity and production of acidic polysaccharide by Vibrio vulnificus.

BACKGROUND: Subinhibitory concentrations of antibiotics, which can occur in vivo, have been demonstrated to alter the production of bacterial virulence factors, including the capsule, or the interaction between microorganism and phagocyte by affecting surface hydrophobicity. METHODS: Using a microtiter assay system, the effect of subinhibitory concentrations of amikacin, gentamicin, cephalothin and doxycycline on the surface hydrophobicity and production of acidic polysaccharide by Vibrio vulnificus (8 human isolates, 8 environmental isolates) was determined. RESULTS: All four drugs, in a dose-dependent manner, caused alterations in adherence to polystyrene, a measure of surface hydrophobicity, and the production of acidic polysaccharides, as determined by Alcian blue staining. CONCLUSION: The changes in capsule production and surface hydrophobicity measured in response to sub-MICs of antibiotics appear to be independent variables.

Effect of insulin on microbial growth.

The ability of insulin to affect the growth kinetics of Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa was measured. For all organisms, insulin, in the absence of a metabolizable sugar source, i.e., glucose or starch in Mueller-Hinton medium, had no effect on generation time as compared with a homologous control. Response to insulin, in the form of increased or decreased generation times, for both Gram-positive and Gram-negative bacteria, was dependent on the concentration of insulin, the concentration of glucose present, and the initial concentration of bacteria exposed to the glucose and insulin.

Carbon source utilisation by Bordetella bronchiseptica.

Bordetella bronchiseptica isolates utilised tricarboxylic acid cycle intermediates -- succinate, citrate, alpha-ketoglutarate, fumarate, lactate and oxalo-acetate; the organic acids pyruvate, acetate and lactate; and the amino acids proline, glutamate, glutamine and tyrosine -- as sole sources of carbon and energy. The inability of B. bronchiseptica isolates, representing the three phase types and from different animal hosts, to utilise carbohydrates and sugar alcohols as sole carbon and energy sources was confirmed and extended. The influence of the carbon substrate on doubling time, piliation, flagellation, motility, capsule production and adherence to mammalian cells was also measured.

Designing an international policy and legal framework for the control of emerging infectious diseases: first steps.

As the pace of emergence and reemergence of infectious diseases quickens, the International Health Regulations, which have served as the legal and policy framework of epidemic control for 45 years, are being revised by the World Health Organization (WHO). In this article, we review the recent history, legal construction, and application of these regulations and related international treaty-based sanitary measures, especially the General Agreement on Tariffs and Trade and the Agreement on the Application of Sanitary and Phytosanitary Measures, and the history of applying the regulations in the maritime and aviation industries. This review indicates that revision efforts should address 1) the limited scope of disease syndromes (and reporters of these syndromes) now in the regulations and 2) the mismatch between multisectoral factors causing disease emergence and the single agency (WHO) administering the regulations. The revised regulations should expand the scope of reporting and simultaneously broaden international agency coordination.

Immune responsiveness in a rat model for type II diabetes (Zucker rat, fa/fa): susceptibility to Candida albicans infection and leucocyte function.

There is a causal relationship between obesity-associated diabetes and an increased risk of infection. The ability of obese (fa/fa) Zucker rats, a model for non-insulin-dependent diabetes mellitus (NIDDM), to clear Candida albicans from the circulation and tissues was compared to that of lean (Fa/fa, Fa/Fa) Zucker rat controls as a measure of immune function. The ID50 necessary to establish tissue colonisation in lean Zucker rats was 1.18 log10 times greater than that determined for the obese Zucker rats. Nine days after intravenous (i.v.) injection of a yeast suspension, the organs of obese rats had a 10-fold greater yeast/g organ burden than did lean rats. The kidney was determined to be the primary target organ for colonisation. Germ-tube formation by C. albicans occurred at a rate 1.5 times faster in serum from obese rats than in serum from lean rats. Peritoneal polymorphonuclear leucocytes, resident macrophages and thioglycollate-elicited macrophages from lean Zucker rats displayed a significantly higher ability to kill ingested yeast cells than analogous cell populations from obese Zucker rats.

Effect of abnormal levels of serum components on antibiotic activity.

Antibiotic activity in serum from a model for type II diabetes was similar to that in normal sera or media containing cholesterol but lacking glucose, insulin, or both. The ratio of effects of broth plus obese-rat serum to effects of broth plus lean-rat serum supplemented with cholesterol approached or equaled 1.

Influence of growth conditions on cell surface hydrophobicity of Candida albicans and Candida glabrata.

The effect of cultural conditions on cell surface hydrophobicity of Candida albicans and Candida glabrata was tested. C. albicans cells grown at room temperature were more hydrophobic than cells grown at 37 degrees C. No consistent pattern was observed with C. glabrata. Relative hydrophobicity was found to vary with the growth phase and growth medium for both species. The implications for pathogenesis studies are discussed.

Adherence of Bordetella bronchiseptica to hamster lung fibroblasts.

The adherence of Bordetella bronchiseptica smooth-, intermediate-, and rough-phase isolates to hamster lung fibroblasts (HLF) (Don line) was characterized by competitive inhibition studies and enzyme and chemical treatments of both the bacteria and the HLF. The adherence of the rough- and intermediate-phase isolates (n = 13) was altered by coincubation of the bacteria and HLF with cationic chelators, including EGTA and citrate. EGTA inhibition of the adherence of the rough- and intermediate-phase isolates could be overcome by the addition of Ca2+, Mn2+, Cd2+, or Sr2+ to the reaction mixture. In addition, citrate released bound bacteria from the HLF. Although the adherence of the smooth-phase isolates (n = 4) was unaltered by cationic chelators, binding was inhibited by N-acetylated amino sugars, with N-acetylglucosamine inhibiting 98% of the adherence of the smooth-phase isolates. Homogenization, protease K, and heat treatment (60 min, 60 degrees C) of the bacteria also resulted in a loss of adherence. It was concluded that B. bronchiseptica can adhere to HLF by at least two mechanisms and that the ligand responsible appears to be a proteinacious, heat labile cell surface component.

Spectral heterogeneity in protein fluorescence of bacteriorhodopsin: evidence for intraprotein aqueous regions.

By the use of derivative spectral analysis, the broad tryptophan (Trp) fluorescence emission from aqueous suspensions of bacteriorhodopsin in its native purple membrane may be resolved into contributions from buried, surface, and exposed residues. Addition of glycerol produces a progressive enhancement of the fluorescence yield to a limiting value at about 70% v/v glycerol. Glycerol enhancement of fluorescence is also observed for monomeric Trp, and a good correlation exists between this effect and literature estimates of the fractional degree of Trp exposure in nine globular proteins. The estimate of fractional Trp exposure in bacteriorhodopsin from this correlation (50 +/- 15%) is in agreement with the value obtained by spectral differentiation and also by modified Stern-Volmer curves for quenching by water-soluble acrylamide. The absence of significant quenching by Tb(III) or Eu(III) ions, which may be expected to bind to the purple membrane surface, shows that the exposed Trp residues are in contact with water in intraprotein regions of the membrane and may be the first direct evidence for a transmembrane aqueous channel by which protons are actively transported during the bacteriorhodopsin photochemical cycle.

Effect of D-mannose and D-glucose on Escherichia coli bacteriuria in rats.

The effect of D-mannose and D-glucose on bacteriuria due to Escherichia coli with mannose-sensitive adhesins was investigated in adult male Sprague-Dawley rats undergoing diuresis. Inocula of 10(5), 10(7), or 10(8) bacteria in 0.1 ml of normal saline or 2.5% or 10% D-mannose or D-glucose were injected intravesically and urine was cultured 1, 3, 5, 7 and 9 days later. The levels of bacteriuria on days 1 and 5 were significantly lower in rats inoculated with 10(5) E coli and 10% D-mannose than in controls (p less than 0.05 and 0.01 respectively) and the percentages of rats with less than 100 bacteria/ml were higher on days 1 and 3 (p = 0.05 and 0.02 respectively). Bacteriuria was significantly lower in rats inoculated with 10(7) bacteria and 10% D-mannose than in controls on days 5 and 7 (p less than 0.01 for each day) and the percentage of rats with less than 100 bacteria/ml was higher on day 7 (p = 0.01). D-glucose reduced bacteriuria significantly only with a concentration of 10% after instillation of 10(5) E. coli (p less than 0.05, day 1). The results indicate that D-mannose and D-glucose can significantly reduce bacteriuria within 1 day and that their efficacy is dependent upon the concentration of both saccharide and bacteria.

Variable adherence of uropathogenic Escherichia coli to epithelial cells from women with recurrent urinary tract infection.

The adherence of 74 Escherichia coli strains to vaginal and buccal epithelial cells from women with recurrent urinary tract infections was studied. The strains were isolated from the urine, vaginal introitus or anal mucosa of women with recurrent bacteriuria. Vaginal and anal isolates were judged to be associated with urinary tract infection if they had the same biotype and serotype as the strain isolated subsequently from the urine. Adherence levels of urinary and anal isolates, and vaginal isolates associated with urinary tract infection were similar for vaginal and buccal cells. Adherence of vaginal isolates not associated with urinary tract infection was significantly lower than adherence of urinary isolates for vaginal (p less than 0.001) and buccal (p less than 0.005) epithelial cells. A positive nonlinear correlation between vaginal and buccal adherence was observed for urinary (r equals 0.87, p less than 0.0001), vaginal (r equals 0.70, p less than 0.0005) and anal (r equals 0.32, p equals 0.047) isolates. Strains of O-serogroups commonly and less commonly associated with bacteriuria had similar adherence. The results suggest that adherence of vaginal isolates is associated with the ability to cause urinary tract infections. The strong correlation between vaginal and buccal cell receptivity suggests that susceptibility to such infections may be controlled by genotypic traits.

Hemagglutination by Bordetella bronchiseptica.

A total of 53 isolates of Bordetella bronchiseptica from dogs and pigs were tested for their ability to agglutinate chicken, horse, sheep, dog, pig, and guinea pig erythrocytes. No differences in hemagglutinating activity were attributed to the animal origin of the bordetella isolates. Horse and dog erythrocytes consistently resulted in the strongest hemagglutination reactions, whereas only 4% of the B. bronchiseptica isolates produced weak agglutination of chicken erythrocytes. A total of 85% of the isolates agglutinated horse, sheep, dog, pig, and guinea pig erythrocytes. One canine isolate with hemagglutinating activity, strain 110H, was examined to determine the nature of the hemagglutinin(s) involved. Hemagglutination was always accompanied by hemadsorption, as determined by dark-field or phase-contrast microscopy. Treatment of cells and cell extracts with heat or protease K inhibited the hemagglutination reaction. Sonicated bacterial cells had a greater hemagglutinating ability than did unsonicated live bacteria. The hemagglutination reaction was not inhibited by any of 17 sugars nor by N- acetylglucosamine or ethylene glycol-bis-(beta-aminoethyl ether)-N, N-tetraacetic acid. Hemagglutinins were not detected in sonic extracts nor in several bacterial subunit fractions, including isolated pili. Antigens in some of these preparations were, however, detectable by indirect hemagglutination with anti-B. bronchiseptica serum. Isolated pili could not be detected on the erythrocyte surface by electron microscopy; however, serial sections of erythrocytes agglutinated by the live Bordetella organisms showed that the bacterial outer membrane and the erythrocyte surface were separated by a space of approximately 20 nm. This study provided additional circumstantial evidence that B. bronchiseptica pili or at least heat-labile surface proteins which extend some distance from the bacterial surface are involved in hemagglutination. Multiple hemagglutinins are likely to exist within this species since one isolate lacking pili also agglutinated canine erthyrocytes. The hemagglutinins of B. bronchiseptica need to be isolated and characterized before the hemagglutination reaction can be applied to studies of attachment.

Adhesion of uropathogenic Escherichia coli to epithelial cells from women with recurrent urinary tract infection.

Adherence of Escherichia coli to human uroepithelial cells obtained from the midstream urine of healthy women, nd to vaginal and buccal cells obtained from 11 healthy women and 24 patients who had had at least three urinary tract infections in the preceding year was studied. Bacteria labeled with [3H] uridine were used, and unattached organisms were separated from the epithelial cells by vacuum filtration through a polycarbonate membrane filter (5-micrometers-pore-size). A day-to-day variation in the receptivity of uroepithelial cells was noted. The range and rapidity of change in adherence to both vaginal and buccal cells were greater in patients than in controls. Adherence to vaginal cells was greater in patients than in controls (10.1 +/- 0.92 vs. 3.8 +/- 0.47 bacteria per cell [mean +/- S. E.], P less than 0.001), as was adherence to buccal cells (1.7 +/- 1.29 vs. 7.1 +/- 0.49, P = 0.002). There was a very strong, positive non-linear correlation between vaginal and buccal cell receptivity (R = 0.87, P less than 0.0001). The data suggest that susceptibility in women to urinary-tract infections is associated with widespread, fluctuating changes in the adhesive characteristics of epithelial cells.