Standardized ginger (Zingiber officinale) extract reduces bacterial load and suppresses acute and chronic inflammation in Mongolian gerbils infected with cagAHelicobacter pylori.

Previous investigations demonstrated that a standardized extract of ginger rhizome inhibited the growth of Helicobacter pylori in vitro with a minimum inhibitory concentration in the range 0.78 to 12.5 mug/mL. In the present work, the extract was tested in a rodent model of H. pylori-induced disease, the Mongolian gerbil, to examine the effects of the extract on both prevention and eradication of infection. The extract was administered to Mongolian gerbils at a daily dose of 100 mg/kg body weight in rations either 3 weeks prior to infection or 6 weeks post-infection. Treatment with the standardized ginger extract reduced H. pylori load as compared with controls and significantly (P<0.05) reduced both acute and chronic muscosal and submucosal inflammation, cryptitis, as well as epithelial cell degeneration and erosion induced by H. pylori. Importantly, the extract did not increase morbidity or mortality. Further investigations of the mechanism demonstrated that the ginger extract inhibited the activity of cyclooxygenase-2, with 50% inhibitory concentration (IC(50)) of 8.5 mug/mL in vitro, inhibited the nuclear factor-kappaB transcriptional response in kBZ Jurkat cells (human T lymphocytes) with an IC(50) of 24.6 mug/mL, and significantly inhibited the release of interleukin (IL)-1beta, IL-6, IL-8, and tumor necrosis factor-alpha from lipopolysaccharide-stimulated human peripheral blood mononuclear cells with IC(50) values of 3.89, 7.7, 8.5, and 8.37 mug/mL, respectively. These results suggest ginger extracts may be useful for development as agents to reduce H. pylori-induced inflammation and as for gastric cancer chemoprevention.

The effect of temperature on the antimicrobial activity of Optisol-GS.

PURPOSE: To determine the survival of different bacteria inoculated in Optisol-GS at refrigerated storage temperature (6 degrees C) and after subsequent warming to room temperature (19-22 degrees C). METHODS: Staphylococcus aureus, Enterococcus faecium, Streptococcus pneumoniae, and Pseudomonas aeruginosa were chosen from stock clinical isolates for inclusion in the study. The first group consisted of 12 Optisol-GS vials. The second group consisted of 12 Optisol-GS vials containing corneas inappropriate for transplantation according to the Eye Bank Association of America (EBAA) protocols. Each group was inoculated with 3 concentrations of approximately 10, 10, and 10 colony-forming units (CFU)/mL of each bacterial species and then refrigerated per EBAA protocol. After 48 hours of refrigeration, all vials were placed at room temperature (RT) and counts were performed at 48, 50 (2 hour RT), 54 (6 hour RT), 60 (12 hour RT), 72 (24 hour RT), and 96 (48 hour RT) hours. At 96 hours, the corneal tissue from 10 and 10 inocula were cultured. All samples underwent serial dilution, spiral plating on blood agar plates, and incubation at 35 degrees C. Viable colony counts were determined at 24 hours. RESULTS: Except for the 10 CFU/mL inocula of P. aeruginosa, all isolates were viable after 48 hours of refrigeration. Rapid bactericidal activity was observed against P. aeruginosa after 2 hours at RT, with complete sterilization by 6 hours. The rate and extent of killing against S. aureus were influenced by the initial inoculum. Bactericidal activity was achieved after 2 hours at RT with 10 CFU/mL of S. aureus versus 24 hours with the 10 inoculum. Of note, bactericidal activity was not observed against S. pneumoniae and E. faecium following 24 hours of storage at RT. The presence of corneal tissue did not affect viable counts, with counts from corneal tissue cultures reflecting the counts seen from Optisol-GS after 48 hours at RT. CONCLUSIONS: The antimicrobial activity of Optisol-GS was reduced at refrigerated temperature and enhanced at RT. Bactericidal activity was not observed against E. faecium at either refrigerated temperature or RT.

Inhibition of uropathogenic Escherichia coli by cranberry juice: a new antiadherence assay.

A combination of microplate technology and turbidity assessment for testing the adherence of P-fimbriated Escherichia coli to human uroepithelial cell line T24, validated with the addition of the known inhibitor 4-O-alpha-D-galactopyranosyl-alpha-D-galactopyranose (galabiose), resulted in a high-throughput, biologically relevant assessment of cranberry (Vaccinium macrocarpon). P-fimbriated ATCC E. coli strains 25922, 29194, and 49161 were inhibited by galabiose. ATCC 29194, a representative urine isolate containing the papGII allele (Class II fimbrial adhesin) and demonstrating the most significant inhibition in the presence of galabiose, was chosen for further testing. In this assay, a low-polarity fraction of cranberry juice cocktail demonstrated dose-dependent inhibition of E. coli adherence. Reported here, for the first time in V. macrocarpon, are 1-O-methylgalactose, prunin, and phlorizin, identified in an active fraction of cranberry juice concentrate. This in vitro assay will be useful for the standardization of cranberry dietary supplements and is currently being used for bioassay-guided fractionation of cranberry juice concentrate.

In vitro synergy testing of levofloxacin, ofloxacin, and ciprofloxacin in combination with aztreonam, ceftazidime, or piperacillin against Pseudomonas aeruginosa.

The synergistic potential of levofloxacin, ofloxacin and ciprofloxacin combined with aztreonam, ceftazidime, or piperacillin was compared using 24 strains of Pseudomonas aeruginosa with varying susceptibility profiles. Levofloxacin and ciprofloxacin demonstrated similar in vitro activity, with ofloxacin demonstrating less activity compared to the other agents. Predominantly additive effects were seen with all combinations, with no significant differences detected between the fluoroquinolone agents.

In vitro bactericidal activity of piperacillin, gentamicin, and metronidazole in a mixed model containing Escherichia coli, Enterococcus faecalis, and Bacteroides fragilis.

An anaerobic, mixed model assay was used to study the bactericidal activities of piperacillin, gentamicin, and metronidazole, alone and in double- and triple-antibiotic combinations against a polymicrobial suspension of E. coli, E. faecalis, and B. fragilis. Only slight differences were noted with the agents when tested against single (10(5) cfu/mL inoculum) versus polymicrobic suspensions (10(6) cfu/mL final inoculum) of susceptible and resistant organisms. Contrary to previous reports in the literature, metronidazole was not active against E. coli in an anaerobic environment (even in the presence of B. fragilis) nor was the activity of metronidazole reduced against B. fragilis in the presence of E. faecalis. Gentamicin demonstrated excellent activity against E. coli when tested in a Bactron anaerobic chamber (5% hydrogen, 5% CO(2,) 90% nitrogen). The pH of the media was only reduced to 6.3-6.7, considerably higher than the pH range of 5-6 needed to significantly reduce the activity of aminoglycosides.

Comparative killing rates of gatifloxacin and ciprofloxacin against 14 clinical isolates: impact of bacterial strain and antibiotic concentration.

The influence of bacterial strain and antibiotic concentration on the time to achieve in vitro bactericidal activity was determined for gatifloxacin and ciprofloxacin using time-kill methodology. Killing rates were significantly affected by bacterial strain, antibiotic concentration, and type of fluoroquinolone. The most rapid bactericidal activity was seen against members of the Enterobacteriaceae and with fluoroquinolone concentrations of 8-16 X MIC. In general, gatifloxacin demonstrated faster killing against Acinetobacter baumanii, Legionella pneumophila, Staphylococcus aureus, and Streptococcus pneumoniae.

Extended-spectrum beta-lactamases: frequency, risk factors, and outcomes.

STUDY OBJECTIVE: To determine epidemiologic factors of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli or Klebsiella pneumoniae in a nonoutbreak setting. DESIGN: Retrospective analysis. SETTING: University teaching hospital. PATIENTS: Fifty-seven patients with cultures of presumed ESBL-producing (i.e., ceftazidime-resistant) E. coli or K. pneumoniae. INTERVENTIONS: To determine overall frequency, institutional antibiograms from 1991-1999 were examined for percentage of isolates with ceftazidime resistance. Medical records from January 1997-June 2000 were reviewed for patient demographics, comorbidities, culture site, antimicrobial therapy, and clinical and microbiologic outcomes. MEASUREMENTS AND MAIN RESULTS: From 1991-1999, frequency increased from undetectable to 4% for ceftazidime-resistant E. coli and from 2% to 6% for ceftazidime-resistant K. pneumoniae. Seventy-one isolates were identified in the 57 patients with presumed ESBL-producing E. coli or K. pneumonia. Fifty-one isolates (72%) were E. coli, with urine the primary site of infection (62%). Eighty-six percent of patients had known risk factors for infection due to ESBL-producing organisms, including hospitalization (37 patients) and residence in long-term care facilities (12 patients). However, in 14% (8 patients), the infection was community acquired in patients who resided at home. CONCLUSION: In addition to known populations at risk, ambulatory patients with chronic conditions represent another patient population that may harbor ESBL-producing organisms.

Ginger (Zingiber officinale Roscoe) and the gingerols inhibit the growth of Cag A+ strains of Helicobacter pylori.

BACKGROUND: Ginger root (Zingiber officinale) has been used traditionally for the treatment of gastrointestinal ailments such as motion sickness, dyspepsia and hyperemesis gravidarum, and is also reported to have chemopreventative activity in animal models. The gingerols are a group of structurally related polyphenolic compounds isolated from ginger and known to be the active constituents. Since Helicobacter pylori (HP) is the primary etiological agent associated with dyspepsia, peptic ulcer disease and the development of gastric and colon cancer, the anti-HP effects of ginger and its constituents were tested in vitro. MATERIALS AND METHODS: A methanol extract of the dried powdered ginger rhizome, fractions of the extract and the isolated constituents, 6-,8-,10-gingerol and 6-shogoal, were tested against 19 strains of HP, including 5 CagA+ strains. RESULTS: The methanol extract of ginger rhizome inhibited the growth of all 19 strains in vitro with a minimum inhibitory concentration range of 6.25-50 micrograms/ml. One fraction of the crude extract, containing the gingerols, was active and inhibited the growth of all HP strains with an MIC range of 0.78 to 12.5 micrograms/ml and with significant activity against the CagA+ strains. CONCLUSION: These data demonstrate that ginger root extracts containing the gingerols inhibit the growth of H. pylori CagA+ strains in vitro and this activity may contribute to its chemopreventative effects.

In vitro susceptibility of Helicobacter pylori to botanical extracts used traditionally for the treatment of gastrointestinal disorders.

The gram-negative bacterium Helicobacter pylori (HP), identified in 1982, is now recognized as the primary etiological factor associated with the development of gastritis and peptic ulcer disease. In addition, HP infections are also associated with chronic gastritis, gastric carcinoma and primary gastric B-cell lymphoma. For centuries, herbals have been used in traditional medicine to treat a wide range of ailments, including gastrointestinal (GI) disorders such as dyspepsia, gastritis and peptic ulcer disease (PUD). However, the mechanism of action by which these botanicals exert their therapeutic effects has not been completely elucidated. As part of an ongoing screening program, the study assessed the in vitro susceptibility of 15 HP strains to botanical extracts, which have a history of traditional use in the treatment of GI disorders. Methanol extracts of Myristica fragrans (seed) had a MIC of 12.5 microg/mL; Zingiber officinale (ginger rhizome/root) and Rosmarinus officinalis (rosemary leaf) had an MIC of 25 microg/mL. Methanol extracts of botanicals with a MIC of 50 microg/mL included Achillea millefolium, Foeniculum vulgare (seed), Passiflora incarnata (herb), Origanum majorana (herb) and a (1:1) combination of Curcuma longa (root) and ginger rhizome. Botanical extracts with a MIC of 100 microg/mL included Carum carvi (seed), Elettaria cardamomum (seed), Gentiana lutea (roots), Juniper communis (berry), Lavandula angustifolia (flowers), Melissa officinalis (leaves), Mentha piperita (leaves) and Pimpinella anisum (seed). Methanol extracts of Matricaria recutita (flowers) and Ginkgo biloba (leaves) had a MIC > 100 microg/mL.

Antifungal susceptibility testing in teaching hospitals.

BACKGROUND: An assessment of antifungal susceptibility testing (AST) has not been conducted since the introduction of the National Committee for Clinical Laboratory Standards (NCCLS) M27-A document. OBJECTIVE: To determine AST practices in teaching hospitals. METHODS: A questionnaire was mailed to the heads of 386 randomly assigned microbiology departments from teaching hospitals identified through the 2000 American Hospital Association Guide. Identifiers were used to delineate responders from nonresponders. A reminder letter was mailed 3 weeks after the initial mailing to all nonresponders. The hospital bed-size and number of inpatient days for respondents were obtained through the American Hospital Directory. RESULTS: The questionnaire was returned by 171 (44.3%) institutions. The total and median (range) number of candida isolates were 137,088 and 8.5 (1-145)/1000 inpatient days for the year 2000, respectively. Approximately 1% (1300) of candida isolates, from predominantly blood specimens, underwent AST. AST was reported by 115 (67.2%) hospitals, with testing on site at 27 hospitals and off site for 88 hospitals. NCCLS methodology (80% broth microdilution) was used by 75% of the hospitals performing on-site AST. The median time to obtain AST results was significantly lower when testing was performed on site (3 d) compared with off site (7-10 d). SUMMARY: A large number of candida bloodstream isolates undergoes AST annually. AST results are obtained sooner when performed on site compared with off site.

Intracellular activity of ABT-773 and other antimicrobial agents against Legionella pneumophila.

The intracellular activity of ABT-773 against Legionella pneumophila was compared with azithromycin and ciprofloxacin using HL-60 cells. Against L. pneumophila ATCC 33152 and three clinical isolates the MICs (mg/L) were ABT-773 0.015, ciprofloxacin 0.03 and azithromycin 0.03. At 48 h, the mean percentage inhibition was as follows: 28.5 +/- 5.9% and 32.6 +/- 4.6% at 8 x and 16 x MIC of ABT-773; 38.1 +/- 8.6% and 48.2 +/- 7.0% at 8 x and 16 x MIC of ciprofloxacin; and 26.3 +/- 9.9% and 28.5 +/- 9.9% at 8 x and 16 x MIC of azithromycin. In this study, all three agents were highly active, with ABT-773 demonstrating similar activity to azithromycin against L. pneumophila.

In vitro bactericidal activity of ABT-773 and amoxicillin against erythromycin-susceptible and -resistant strains of Streptococcus pyogenes.

The bactericidal activity of ABT-773 was compared with amoxicillin against 10 clinical isolates of S. pyogenes (six erythromycin susceptible and four erythromycin resistant). The MIC ranges (mg/L) were 0.004-0.25 of ABT-773 and 0.015-0.12 of amoxicillin. At 24 h, ABT-773 concentrations of 2 x MIC and 8 x MIC were bactericidal against three and six organisms, respectively. In comparison, amoxicillin was bactericidal against all 10 organisms at both test concentrations.

Effect of perfluorooctyl bromide on bacterial growth.

BACKGROUND: Perfluorooctyl bromide (PFOB) is administered directly into the lungs of critically ill patients during partial liquid ventilation. This adjunctive therapy facilitates respiratory support in lung-injured patients and potentially interacts with pathogens in patients with pneumonia. The purpose of this study was to determine the interaction of PFOB with Pseudomonas aeruginosa. METHODS: The antimicrobial activity of PFOB against P. aeruginosa was determined using modified time-kill methods. PFOB concentrations of 25, 50, 75, 90 and 99% were studied. Electron microscopy was used to evaluate morphologic changes following PFOB exposure to the organism. RESULTS: Viable counts at baseline were approximately 1 log(10) lower when P. Aeruginosa was exposed to PFOB compared to controls. Significant bacterial killing occurred over the first 2 h for the 90% (p = 0.023) and 99% (p = 0.045) PFOB concentrations versus control. Electron microscopy demonstrated that PFOB disturbs the bacterial cell wall, and produces vacuolizations within the cell. CONCLUSIONS: PFOB kills P. aeruginosa in a concentration-dependent manner through disruption of the cell architecture.

Combined bactericidal activity of perfluorooctyl bromide and aminoglycosides against Pseudomonas aeruginosa.

UNLABELLED: Perfluorooctyl bromide (PFOB) may be useful as a medium for antibiotic delivery to treat pneumonia during liquid ventilation. OBJECTIVE: The purpose of the study was to determine the antibacterial activity of PFOB either alone or in combination with aminoglycosides against Pseudomonas aeruginosa. DESIGN: Modified time-kill assays were used to determine antibacterial activity: an inoculum of 1 x 10(5) cfu/mL was added to PFOB, or PFOB + an aminoglycoside (1 x MIC). Viable counts were performed at 0, 0.25, 0.5, 0.75, 1, 2, 4 and 6 h. Electron microscopy was used to visualize the effect. Approximately 1.5 x 10(8) cfu/mL of bacteria were added to HEPES buffer (control), PFOB, gentamicin and PFOB + gentamicin. At baseline and 0.5 h, the bacteria were viewed under 20,000x magnification for both negative staining and thin-sectioning experiments. RESULTS: Exposure to PFOB alone resulted immediately in a >90% reduction in the inoculum at baseline compared with control (P = 0.001). Following the initial reduction in colony count, bacteria grew in a similar manner to controls for PFOB-exposed strains. Aminoglycosides, alone at 1 x MIC or with PFOB, produced a bacteriostatic effect over the 6 h period. PFOB-exposed P. aeruginosa showed cell wall irregularity under electron microscopy. The gentamicin-exposed P. aeruginosa showed blebbing. PFOB + gentamicin caused extensive cell wall damage, exhibiting the additive effects of PFOB and gentamicin. CONCLUSION: PFOB appears to affect the cell wall of P. aeruginosa and enhance the bacterial cell destruction caused by aminoglycosides. The combined antibacterial effect of PFOB with the aminoglycosides is greater than that observed with these agents alone.

In vitro bactericidal activities of ABT-773 against ermB strains of Streptococcus pneumoniae.

The bactericidal activities of ABT-773, a new ketolide, were compared to those of cefuroxime and amoxicillin-clavulanate against 10 strains of Streptococcus pneumoniae containing the ermB gene. MICs and time-kill curves were determined in duplicate per NCCLS guidelines with cation-adjusted Mueller-Hinton broth with 3% lysed horse blood. Viable counts were done at 0, 2, 6, and 24 h. Antibiotic concentrations tested were two and eight times the MIC. ABT-773 MICs ranged from 0.008 to 1.0 micro g/ml. Bactericidal activity was observed with ABT-773 at eight times the MIC against 4 of 10 strains at 24 h compared to 10 of 10 strains with the beta-lactam antibiotics.

In vitro susceptibility of Helicobacter pylori to isoquinoline alkaloids from Sanguinaria canadensis and Hydrastis canadensis.

Methanol extracts of the rhizomes of Sanguinaria canadensis, and the roots and rhizomes of Hydrastis canadensis, two plants used traditionally for the treatment of gastrointestinal ailments, were screened for in vitro antibacterial activity against 15 strains of Helicobacter pylori. The rhizome extracts, as well as a methanol extract of S. canadensis suspension-cell cultures inhibited the growth of H. pylori in vitro, with a MIC50 range of 12.5-50.0 microg/ml. Three isoquinoline alkaloids were identified in the active fraction. Sanguinarine and chelerythrine, two benzophenanthridine alkaloids, inhibited the growth of the bacterium, with an MIC50 of 50.0 and 100.0 microg/ml, respectively. Protopine, a protopine alkaloid, also inhibited the growth of the bacterium, with a MIC50 of 100 microg/ml. The crude methanol extract of H. canadensis rhizomes was very active, with an MIC50 of 12.5 microg/ml. Two isoquinoline alkaloids, berberine and beta-hydrastine, were identified as the active constituents, and having an MIC50 of 12.5 and 100.0 microg/ml, respectively.

Antimycobacterial Naphthopyrones from Senna obliqua.

Bioactivity-directed fractionation of the methanolic extract of the stem and fruits of Senna obliqua led to the isolation of two known antimycobacterial natural products, quinquangulin (1) and rubrofusarin (2). Both compounds had minimum inhibitory concentrations (MICs) of 12.0 microg/mL against Mycobacteriatuberculosis in radiometric culture. This is the first report of antimycobacterial activity associated with naphthopyrone compounds. Their structures were determined by spectroscopic means including 1D and 2D NMR techniques and further confirmed by X-ray crystallographic analysis.

Pharmacokinetics and pharmacodynamics of intravenous levofloxacin at 750 milligrams and various doses of metronidazole in healthy adult subjects.

The purpose of this investigation was to evaluate the steady-state pharmacokinetics, pharmacodynamics, and safety of intravenous levofloxacin at 750 mg administered once daily combined with three different dosages of intravenous metronidazole (500 mg every 8 h [q8h], 1,000 mg q24h, and 1,500 mg q24h). Eighteen healthy adult subjects received all three combinations in a randomized, crossover fashion. Serial blood and urine samples were collected on the third day of each study period. The 24-h areas under the inhibitory (AUIC(0-24)) and bactericidal (AUBC(0-24)) curves of these three combination regimens were determined against clinical isolates of Bacteroides fragilis, Bacteroides thetaiotaomicron, Peptostreptococcus asaccharolyticus, and Escherichia coli. The mean concentrations of levofloxacin were not different between study periods and were similar to those previously published. The mean (+/- standard deviation) areas under the metronidazole plasma concentration-time curve (AUC(0-24)) for 1,500-mg q24h (338 +/- 105 mg.h/liter) and 500-mg q8h (356 +/- 68 mg.h/liter) regimens were not different (P > 0.05), but both were significantly higher than the 1,000-mg q24h AUC(0-24) (P < 0.05, 227 +/- 57 mg.h/liter). Mean (+/- standard deviation) total body clearance and renal clearance values were similar among the 500-mg q8h, 1,000-mg q24, and 1,500-mg q24h regimens (62 +/- 7, 67 +/- 13, and 67 +/- 14 and 11 +/- 3, 12 +/- 2, and 12 +/- 5 ml/min/1.73 m2, respectively). Levofloxacin at 750 mg q24h plus metronidazole at 500 mg q8h or 1,500 mg q24h resulted in similar AUIC(0-24) and AUBC(0-24) values with one exception: the AUIC(0-24) for the 1,500-mg q24h regimen against B. thetaiotamicron was significantly higher (P < 0.05) than those of the other regimens. Overall, the combination of levofloxacin at 750 mg once daily and metronidazole at 500 mg q8h or 1,500 mg q24h appeared to have greater AUIC(0-24) and AUBC(0-24) values than did the 1,000-mg q24h regimen. All combination regimens of levofloxacin and metronidazole were well tolerated, and no serious drug-related adverse effects were reported. The pharmacokinetic, safety, and pharmacodynamic data from our study suggest that a once-daily regimen of intravenous levofloxacin at 750 mg and metronidazole at 1,500 mg warrants further clinical investigation.