E. De Vecchi

Effects of Lactobacillus salivarius LS01 (DSM 22775) treatment on adult atopic dermatitis: a randomized placebo-controlled study.

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by xerosis, pruritus and eczema. The role of probiotics in the prevention and the treatment of AD have been extensively studied in children with controversial results while there are few studies on an adult population. The aim of this randomized, double-blind, placebo-controlled study is to evaluate the clinical efficacy of the intake of a probiotic strain (Lactobacillus salivarius LS01) in the treatment of adult patients with AD. A group of 38 patients was treated with probiotics or placebo (maltodextrin) for 16 weeks. The study was performed from January (T0) to May, 2009 (T16). The assessment of efficacy was based on change in SCORAD (SCORing Atopic Dermatitis) index, dermatology life quality index (DLQI) improvement, cytokine production by PBMCs and ability to modify faecal microbial flora. No significant adverse events were recorded during the study. Patients treated with probiotics showed a statistically improvement of both clinical parameters (SCORAD p< 0.0001 and DLQI p= 0.021) at the end of treatment (T16) compared with the placebo group. Furthermore, after four months of treatment there was a significant reduction of Th1 cytokines (IL-12+IFNγ) (p= 0.03) and Th1/Th2 ratio (IL-12+IFNγ/IL-4+IL-5) (p= 0.019) only in placebo-treated patients. A statistically relevant decrease of staphylococci in faeces of the probiotic-treated group was also observed at the end of treatment. In our study, the administration of L. salivarius LS01 was well tolerated and was associated with a significant improvement of clinical manifestation and QoL. This probiotic strain could have an important role in modulating Th1/Th2 cytokine profiles and could be considered as an important adjunctive therapy in the treatment of adult AD.

In vitro antimicrobial activity of a novel propolis formulation (Actichelated propolis)

Aims: This study compared in vitro activities of Actichelated® propolis (a multicomposite material obtained with mechano‐chemichal activation) and of a hydroalcoholic extract of propolis.

Microbiological Evaluation of Commercial Probiotic Products Available in the USA in 2009

Abstract Probiotics are widely used to prevent and treat several diseases. Many commercial products are available worldwide. However, there is no clear international or local legislation about them and previous studies showed that most of the tested products are not in conformity with international guidelines. The aim of this study was to determine if products available in the USA market in 2009 were correctly labeled in terms of quantity of viable bacteria, identification of species and cross contamination by species not on the label. Disturbingly, we found that only 4 of 13 products (31%) were in accordance with label claims. Our results suggest the need for adequate control of probiotic production as well as periodical screenings by competent organizations to monitor the effect of storage on product quality.

Microbiological Evaluation of Commercial Probiotic products available in Italy

Abstract Scientific evidence of the prevention and therapy of some intestinal diseases is accumulating in regard to probiotic products. However, sufficient information on the use of probiotics in specific therapies is not yet available and, above all, there is no clear legislation about these products in Europe. In this study, we evaluated five different probiotic products commercially available in Italy for their qualitative and quantitative microbial content after about 12 and 22 months of storage. We also evaluated the stability of lactobacilli to 0.3% bile salts and to pH of 3.58 and 7.98. There were discrepancies between the declared content and our results found after storage for 4 of the tested products. Bile salts and basic pH did not affect the growth of the lactobacilli tested, while for 2 tested products 6 hours at acid pH produced a complete inhibition of bacterial growth. Our results suggest the need for clear legislation and adequate control of the manufacturing of probiotic products.

Comparative evaluation of synergy of combinations of β-lactams with fluoroquinolones or a macrolide in Streptococcus pneumoniae

OBJECTIVES Streptococcus pneumoniae has shown a great ability to develop efficacious mechanisms of resistance to the main drugs for the treatment of pneumonia, such as β-lactams, macrolides and fluoroquinolones. The present study aimed to compare the antipneumococcal activity of combinations of respiratory fluoroquinolones with cephalosporins (either parenteral or oral) or protected penicillin versus the standard combinations (i.e. a macrolide with a protected penicillin or cephalosporin) against 100 isolates with different susceptibilities to macrolides and/or penicillin. METHODS Chequerboard assays for all isolates and time-kill curves for nine isolates with different patterns of susceptibility were performed. Synergy between antibiotics at serum peak concentrations was also determined. RESULTS The combination of levofloxacin with ceftriaxone produced the highest rate of synergy (54/100), mainly against macrolide-resistant strains (22/30). Antagonism was not observed for any tested combination apart from clarithromycin with amoxicillin/clavulanic acid (22/100 isolates). Although the killing activities of all antibiotics improved when they were tested in combination, synergy was observed only for some combinations after 12 and/or 24 h. Serum concentrations were effective in inhibiting the growth of the tested strains. CONCLUSIONS Combinations of levofloxacin with parenteral cephalosporins were the most active among all the tested combinations, while antagonism occurred when clarithromycin and amoxicillin/clavulanic acid were tested.

In vitro selection of resistance in Streptococcus pneumoniae at in vivo fluoroquinolone concentrations

OBJECTIVES To compare the ability to select for resistance in Streptococcus pneumoniae of levofloxacin, moxifloxacin, ciprofloxacin and prulifloxacin. METHODS Twenty strains of S. pneumoniae susceptible to fluoroquinolones were used. The frequencies of spontaneous single-step mutations at plasma and epithelial lining fluid (ELF) peak and trough antibiotic concentrations were calculated. Multi-step selection of resistance was evaluated by performing 10 serial subcultures on agar plates containing a linear gradient from peak to trough antimicrobial concentrations, followed by 10 subcultures on antibiotic-free agar. Resistant strains selected after multi-step selection were characterized for DNA mutations by sequencing gyrA, gyrB, parC and parE genes. RESULTS Levofloxacin and moxifloxacin showed the lowest frequencies of mutations (median <10(-11)) at plasma peak and at ELF concentrations, while medians ranging from 10(-8) to 10(-6) were observed for ciprofloxacin and prulifloxacin. In a multi-step selection assay, ciprofloxacin and prulifloxacin selected for the highest number of resistant strains (19 and 31, respectively). No selection of resistance was observed for levofloxacin at ELF concentrations and for moxifloxacin at plasma and ELF concentrations. Mutations in parC, parE and gyrA genes were found in ciprofloxacin- and prulifloxacin-resistant strains, while only parC mutations were found for levofloxacin. CONCLUSIONS Levofloxacin and moxifloxacin are characterized by a lower propensity to select in vitro for resistance in S. pneumoniae than ciprofloxacin and prulifloxacin, when tested at plasma and lung concentrations.

In Vitro Synergy and Selection of Resistance by Fluoroquinolones Plus Amikacin or β-Lactams Against Extended-Spectrum β-Lactamase-Producing Escherichia coli

Abstract This study compared the potential synergy of levofloxacin and ciprofloxacin in combination with cefepime, ceftazidime, imipenem, piperacillin/tazobactam or amikacin, against extended-spectrum β-lactamase (ESBL)-producing Escherichia coliby using checkerboard and time kill studies. Moreover, selection of resistance was determined by frequency of mutations and by calculating the increase in minimum inhibitory concentrations (MICs) after five serial subcultures on antibiotic-containing plates. Synergy occurred more often with levofloxacin combined with imipenem (7/10 strains) and with levofloxacin or ciprofloxacin with amikacin (10/10) than for the other combinations. Time kill studies showed synergy for levofloxacin combined with amikacin, ceftazidime, imipenem or piperacillin/tazobactam, and for ciprofloxacin combined with amikacin, cefepime or imipenem. Antibiotic combinations selected for resistance less frequently than antibiotics alone. Mutation frequency was <10−12 for all combinations. In conclusion, the combination of a fluoroquinolone with a β-lactam or amikacin may provide improved antimicrobial activity and help limit the occurrence of resistance in ESBL-producing E. colistrains.

Should Lactobacillus sporogenes and Bacillus coagulans have a future

Abstract Probiotics are gaining increasing scientific and commercial interest as functional foods. Their success has led to the development and marketing of a broad range of products based on probiotics. In this context, resolution of the taxonomy of microbial species remains a key point, since different species belonging to the same genus may have different beneficial properties. Lactobacillus sporogenes, which should be correctly classified as Bacillus coagulans, represents the archetypal misidentified probiotic and its inclusion among probiotics has often been a matter of debate. Since this bacterium shows characteristics of both genera Lactobacillus and Bacillus, its taxonomic position between the families lactobacillaceae and bacillaceae has often been discussed. This review summarizes the salient probiotic features of L. sporogenes/B. coagulans by examining currently available information. Although the use of L. sporogenes spores as a probiotic has increased in recent years, clinical evidence of its benefits are limited to only a few studies involving small patient populations.

In Vitro Antiviral Activity of Resveratrol Against Respiratory Viruses

Resveratrol (trans-3,5,4 -trihydroxystilbene), a non-flavonoid polyphenol, is an antibacterial and antifungal chemical produced by plants as a defense against infection 1. In recent decades resveratrol has been associated with a surprising number of health benefits, most notably the mitigation of age-related diseases, including neurodegeneration, carcinogenesis and atherosclerosis 2-8. Moreover, it has been shown to promote survival and longevity by activating sirtuins, thus extending the lifespan of various organisms from yeasts to vertebrates 9,10. Its powerful antioxidant property and its ability to mediate important cellular signaling pathways, such as those activated by caloric restriction in mammals, seem to be pivotal for resveratrol activity 9,11-14. The increasing evidence in the involvement of oxidoreductive cellular balance in viral infections and the potent antiviral activities exhibited by certain antioxidant molecules have led to evaluation of the antiviral potential of resveratrol. It has been shown to block the nuclear-cytoplasmic translocation of viral ribonucleoproteins and reduced expression of late viral proteins of influenza A virus 15; to prolong the S phase of the cell cycle, thus allowing a more potent antiviral activity of some anti-HIV drugs 16,17. Resveratrol has been shown to interfere with the first stage of varicella zoster virus replication and to impair expression of essential immediate-early, early and late HSV genes and synthesis of viral DNA 18,19. In this study the antiviral activity of resveratrol water solution (Noos, Rome, Italy) was tested against one strain each of adenovirus, influenza virus A and respiratory syncytial virus from our laboratory collection. Isolates were maintained in MEM medium supplemented with 10% fetal calf serum (FCS) and 1% Lglutamine at –80° C prior to the study. Once thawed, isolates were inoculated onto Hep-2 cell monolayer until 75% or more of the monolayer showed a cytopathic effect (CPE). Then they were centrifuged and the supernatant used for the susceptibility study. Antiviral activity of resveratrol was evaluated according to the cytopathic effect inhibition assay as described by Cotarelo et al. 20. The assay is characterized by sensitivity and specificity comparable to the plaque reduction assay. To this purpose, serial ten-fold dilutions of the viral isolates were inoculated onto Hep-2 cell monolayers growing in 24-well plates, containing MEM (Euroclone, Pero, Italy) with 2% FCS, and 1% glutamine. Antiviral activity of resveratrol was assessed at concentrations of 2, 1, 0.5, 0.25 and 0.125 mg/mL. A positive control with virus but not resveratrol and a growth control with cells alone were also included. The lack of cytotoxicity of resveratrol on the Hep-2 cells was tested by incubating cells with the same amounts of compound but without viral isolates. Plates were then incubated at 37°C with 5% CO2 for at least 48 h. After this incubation period, formation of a cytopathic effect (CPE) was observed using an inverted light microscope at 400 X magnification. If the viral dilution in the set without resveratrol was at least one log10 greater than that obtained in the wells containing it, then that resveratrol concentration was considered able to reduce viral growth. If viral dilutions obtained with and without resveratrol were equal then that concentration was considered unable to inhibit that particular virus. Each virus was tested in triplicate. Resveratrol active concentrations are reported in Table 1. Resveratrol activity against some viruses has been previously demonstrated in a few studies. This compound inhibited replication of some herpesviruses such as herpes simplex 1 and 2, cytomegalovirus and varicella zoster virus, while it seemed not to be active against herpes virus 6 18,21-23. Influenza A, an orthomyxovirus, was also inhibited by resveratrol 15. Synergy between resveratrol and nucleoside analogs has been observed against HIV-1 17. Together with our findings, these reports suggest that resveratrol is characterized by a broad spectrum of anti-viral activities and may inhibit replication of some viruses.

Effect of Moxifloxacin on Bacterial Pathogenicity Factors in Comparison with Amoxicillin, Clarithromycin and Ceftriaxone

Abstract Moxifloxacin is a recent fluoroquinolone with an antibacterial spectrum encompassing both aerobic Gram-negative and Gram-positive strains, as well as anaerobic bacteria. In this study the activity of moxifloxacin against Streptococcus pneumoniae, Staphylococcus aureus, Moraxella catarrhalis, Haemophilus influenzae, Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa, and effects of subinhibitory concentrations on bacterial morphology and adhesion properties were compared with those of amoxicillin, clarithromycin and ceftriaxone. The in vitro activity of moxifloxacin against Gram-positive and Gram-negative pathogens was equal to or better than that of comparators. Subinhibitory concentrations of moxifloxacin significantly affected bacterial morphology of S. pneumoniae, M. catarrhalis, H. influenzae and P. aeruginosa, leading to formation of spherical forms and filaments. Moreover, bacterial adhesion to buccal cells and fibroblasts was reduced after treatment with 1/4 and 1/8 X MIC of moxifloxacin. In conclusion, subinhibitory concentrations of moxifloxacin remarkably interfere with some bacterial pathogenic factors, thereby contributing to its antimicrobial activity.