Fabrizio Pregliasco

Probiotics and health: An evidence-based review

The intestinal microbiota is an ecosystem formed by a variety of ecological niches, made of several bacterial species and a very large amount of strains. The microbiota is in close contact with the intestinal mucosa or epithelial interface which is, after the respiratory area, the largest surface of the body, occupying approximately 250-400 m(2). The physiological activities of the microbiota are manifold and are just being unraveled. Based on the observations of the multiple roles played by the microbiota in health and disease, the notion of modifying it with appropriate formulations, i.e. probiotics, is being tested in several settings. This review summarizes the current knowledge on probiotics and discusses both limitations and acquired evidence to support their use in preventive and therapeutic medicine.

A New Chance of Preventing Winter Diseases by the Administration of Synbiotic Formulations

Background The efficacy of probiotics is currently well documented with regard to the improvement of gastrointestinal functions, whereas their potential role in the prevention of infectious respiratory diseases has not been sufficiently analyzed. Purpose of the Study and Methods A 3-stage prospective, randomized, double blind, placebo-controlled study was carried out with several synbiotic preparations containing 3 to 5 strains of Lactobacillus plantarum, Lactobacillus rhamnosus, and Bifidobacterium lactis, lactoferrin and prebiotics such as either FOS (short-chain fructooligosaccharides) or GOS (galactooligosaccharides). The study was performed over 3 different winter seasons between 2003 and 2007, and was aimed at assessing the ability of the different preparations to improve intestinal functions and to increase the bodys defences against respiratory infections. In 2003/04 (stage 1; 237 healthy volunteers) an active formulation (A) containing 3 probiotic strains and FOS was used versus placebo; in 2005/06 (stage 2; 234 healthy volunteers) the same formulation versus a similar preparation enriched with lactoferrin (B), and versus placebo; in 2006/07 (stage 3; 250 healthy volunteers), 2 new synbiotic formulations each containing 5 probiotics and FOS (C) or GOS (D), respectively, versus placebo. Results In stage 1, bowel functions improved (P=0.004) in terms of reduced bloating and more regular intestinal motility. The length of acute respiratory infection episodes considered as a whole (−0.97 d; P=0.007) and upper respiratory tract infections (URTIs, −1.96 d; P=0.044) were significantly decreased in the synbiotic group. The severity of episodes recorded a statistically significant drop in both episodes considered as a whole (3.21 average score vs. 3.98 in the placebo group, P<0.001) and in URTI (2.56 vs. 3.82; P=0.004) and flu classes (3.80 vs. 4.67, P=0.001). In stage 2, improvement of bowel functions was statistically significant (P=0.005) in synbiotic preparation A. A statistically significant reduction in the number of respiratory tract infections episodes was noted with both the two active formulations (P=0.002 in group A and P=0.003 in group B). The duration of episodes considered as a whole (−1.12 d in one of the 2 active formulation groups; P=0.005), URTIs (−2.08 d in group A; P=0.036) and influenza-like illness episodes (−1.40 d in group A; P=0.049) was significantly decreased in the synbiotic group. A reduction trend in cold episodes was also recorded. The severity of episodes recorded a statistically significant drop in episodes considered as a whole (−0.73 in group A, P=0.003; −0.65 in group B, P=0.004) and in the case of flu (−1.25 in group A, P<0.001; −1.18 in group B, P<0.001). In stage 3, the improvement of bowel functions was confirmed for both active formulations (P<0.001). A significant decrease in the total length of respiratory episodes (−1.51 d; P<0.001 in the group C and −1.39 d; P<0.001 in the group D) and in the length of cough (−3.08 d; P<0.001 in group C; −2.83 d; P<0.001 in group D), cold (−1.02 d; P=0.019 in group C; −1.32 d; P=0.001 in group D) and flu episodes was reported. The severity of episodes recorded a statistically significant drop in regard to episodes considered as a whole, the cold and flu classes in both groups and for cough too in group C. The number of episodes also dropped considerably in terms of overall episodes, cold (group C) and flu. Conclusions These results demonstrate that a regular, long-term intake of various synbiotics may improve health by reducing the incidence and severity of respiratory diseases during the cold season.

Comparison of RT‐PCR with other diagnostic assays for rapid detection of influenza viruses

To compare the effectiveness of reverse transcription‐polymerase chain reaction (RT‐PCR), shell vial culture and cytospin assay as laboratory techniques for rapid diagnosis of influenza infections, a retrospective study was carried out on 270 aliquots of oropharyngeal swabs collected from October 1993 to March 1996 and already characterized by standard isolation procedures, and a prospective study in which 65 clinical samples taken from patients with influenza‐like syndrome between October 1996 and March 1997 were tested. In the retrospective study, using conventional isolation as the gold standard, the sensitivity of RT‐PCR and cytospin assay for virus A was 100% (95% confidence interval (CI), 89.1–100) and for virus B it was 100% (95% CI, 56.1–100) compared with 77.5% (95% CI, 61.1–88.6) and 71.4% (95% CI, 30.3–94.9) for shell vial culture. The specificity of all the three assays was 100% (95% CI, 98.0–100) for virus A and 100% (95% CI, 98.2–100) for virus B. In the prospective study the sensitivity of RT‐PCR was greater than that of the other tests considered, both rapid and standard. It is suggested that RT‐PCR should be employed in combination with conventional culture techniques in routine diagnosis of influenza infections in order to obtain results more rapidly and to improve virus detection even in circumstances in which standard isolation could be problematic. J. Med. Virol. 56: 168–173, 1998.

Antibodies to hepatitis C virus in community-acquired acute non-A, non-B hepatitis

Circulating antibodies to the recently identified hepatitis C virus (anti-HCV) have been investigated by ELISA in a series of 129 adult Italian patients with acute, community-acquired non-A, non-B hepatitis. Anti-HCV was detected in 50 (38%) cases with a prevalence rate which increased from 19%, in sera taken during the first 2 weeks of illness to 52% in samples obtained 5-6 weeks after onset, indicating a rather late appearance of the antibody. Anti-HCV positivity was independent of risk factors in the clinical history, but correlated with the outcome of the disease. Eighteen (26%) of 68 patients who recovered were anti-HCV positive compared to 10 of 14 (71%) who progressed to chronicity (p less than 0.01). In this latter group the antibody persisted for more than 12 months after the onset of the illness. Conversely, in 12 (85%) of 14 serially tested patients who recovered, anti-HCV positivity was transient, lasting from a few weeks to a few months. These findings indicate that HCV is implicated in a consistent proportion of acute community-acquired non-A, non-B hepatitis cases, particularly cases which progress to chronicity. A large proportion of cases remained unclassified, however, and it will be important to define whether they represent cases of HCV infection with poor serologic response, or are due instead to other, as yet unidentified, non-A, non-B agents.

Immunization in children with HIV seropositivity at birth : antibody response to polio vaccine and tetanus toxoid

ObjectiveTo evaluate the humoral response to routine childhood immunization of HIV-infected children. DesignResponse rate, antibody titres and persistence after polio and tetanus vaccination were compared in 72 children with HIV seropositivity at birth and divided according to HIV infection status as determined by clinical and laboratory tests. MethodsPolio antibodies were titred in a microneutralization test (positive titres, ≥1:4), and antibody to tetanus toxoid with a passive haemagglutination method (protective titres, ≥1:1024). ResultsThe response rates to polio and tetanus vaccination (>80 and >75%) were similar in the HIV-infected and non-infected children, as were antibody levels. In the subgroup with sera obtained some months after the last dose of vaccine, polio antibody levels decreased in all four HIV-infected and in three of the seven non-infected children; protective tetanus antitoxin levels were detected in three of the six infected and in all three non-infected children. ConclusionsThis study demonstrates the ability of children with HIV infection to respond adequately to the two vaccines considered, although tetanus antitoxin levels were inferior, compared with those in the seroreverted children. The unsatisfactory antibody levels observed in the admittedly few HIV-positive children studied some months after the last vaccination could be the result of a lower initial protective level and not necessarily an expression of severely impaired immunocompetence. The administration of booster doses in addition to the traditional immunization schedule could be useful in children with HIV infection.

Simultaneous influenza and pneumococcal vaccination in elderly individuals.

The study was performed to evaluate the effects of influenza and pneumococcal vaccines administered alone or in combination. 124 elderly subjects living in community were vaccinated either with influenza split vaccine or with pneumococcal 23-valent or with both vaccines at the same time in different sites. Sera were tested for hemoagglutination inhibiting antibodies for influenza and for antibodies against 23-valent vaccine for streptococcus pneumoniae. No side effects were observed in the vaccinated population. Serological results indicated that influenza vaccine increased significantly antibody levels. No difference was observed between the group which received influenza vaccine alone and that which received influenza and pneumococcal vaccines associated, considering either G.M.T or the percentages of protected individuals or the percentages of subjects who seroconverted. When pneumococcal vaccine was administered at the same time with influenza vaccine, there was a not statistically significant reduction in both mean antibody concentration and mean fold increase. It is concluded that the simultaneous administration of influenza and pneumococcal vaccines to elderly individuals, including subjects at risk, is safe, effective and economically advantageous.

Does immunoglobulin interfere with the immunogenicity to Pasteur Mérieux inactivated hepatitis A vaccine

BACKGROUND/AIMS The aim of this study was to compare the immunogenicity of Pasteur Mérieux (P.M. s.v.) inactivated hepatitis A vaccine when given alone with its immunogenicity when given in combination with immunoglobulin. METHODS We enrolled 80 healthy volunteers who were seronegative for anti-HAV. Forty subjects (group A) were given two doses of vaccine at 0 and 6 months plus 4 ml of immunoglobulin given simultaneously with the first vaccine injection; and 40 subjects (group B) were given vaccine alone. The population characteristics (age, sex, height and weight) of the two groups were comparable. RESULTS Anti-HAV antibody was detectable at week 1 in 100% of group A and in 5.7% of group B, and in 100% of both groups at 4 and 8 weeks. Seroconversion rates (> or = 20 mIU/ml) were 97.4% in group A and 100% in group B at week 24 and were 100% in both groups 4 weeks after a booster injection at 6 months. The antibody response level was lower after concomitant administration of vaccine with immunoglobulin. The antibody geometric mean titer was higher at week 1 in subjects who had been given vaccine and immunoglobulin, but nearly 50% lower at week 4 and thereafter, indicating inhibition of the vaccine-induced immune response by immunoglobulin. At week 28, i.e. 4 weeks after the booster injection, geometric mean titers had increased about 13-15 times in both groups, reaching highly protective antibody levels (3351 mIU/ml in group A and 5843 mIU/ml in group B). No serious adverse effects were observed during the follow-up. CONCLUSIONS These data indicate that P.M. s.v. hepatitis A vaccine is highly immunogenic and safe, even when given simultaneously with immunoglobulin. Despite the interference of the immunoglobulin with the active immune response, individuals who were immunized passively plus actively also developed high titers of anti-HAV antibody. It is therefore reasonable to expect that this inhibition will not affect the overall protection conferred by the vaccine.

Environmental surveillance of Legionella pneumophila in two Italian hospitals

The aim of this study was to identify the most effective disinfection protocol to reduce the presence of Legionella pneumophila in the water system of two Italian hospitals. From 2004 to 2009, 271 samplings of hot water were carried out in 11 hospital units to detect the presence of L. pneumophila. Additionally, water samples collected from one boiler outlet and the hot water recirculation were tested. From 2004 to 2009, L. pneumophila was present in 37% of the samples. Of these, 68.3% and 18.8% were positive for serogroups 2-14 and 1, respectively. Furthermore, 12.9% of the samples were positive for both serogroups. Finally, a maximal count of 10(4) CFU/L was measured in the most distal sites. To reduce L. pneumophila colonization, a two-year long hyperchlorination (2004-2006) was carried out. Moreover, from June 2005 until now, continuous maintenance of boilers and tanks, substitution of the shower heads and increase of the boiler outlet temperature to 60 °C were performed. All these treatments led to a marked reduction of L. pneumophila colonization in the short but not in the medium-long term. Only the use of chlorine dioxide led, after four years, to a reduction of the loads of L. pneumophila to values below 100 CFU/L. However, in the distal sites a persistent degree of colonization (maximum value 700 CFU/L, average 600 CFU/L) was observed probably due to the presence of L. pneumophila in the stagnant water in dead legs. In conclusion, data show that long-term chlorination of hot water sources together with carefully aimed maintenance of water pipes can lead to an effective reduction of L. pneumophila concentration in hospital water systems.

A seroepidemiologic survey of immunity against poliomyelitis in a group of HIV positive and HIV negative drug addicts.

In a seroepidemiological study performed to investigate immunity against poliomyelitis in a population of drug addicts in a rehabilitative residential centre we demonstrated a widespread lack of poliovirus neutralizing antibodies. This was more evident in the HIV positive subjects, 27% of whom were seronegative for poliovirus type 1, 27% for type 2 and 34% for type 3, with 11% seronegative for all three types. These results indicate a gap in immunity to poliomyelitis in the examined population.

Human Herpesvirus-8 Infection Leads to Expansion of the Preimmune/Natural Effector B Cell Compartment

Background Human herpesvirus-8 (HHV-8) is the etiological agent of Kaposis sarcoma (KS) and of some lymphoproliferative disorders of B cells. Most malignancies develop after long-lasting viral dormancy, and a preventing role for both humoral and cellular immune control is suggested by the high frequency of these pathologies in immunosuppressed patients. B cells, macrophages and dendritic cells of peripheral lymphoid organs and blood represent the major reservoir of HHV-8. Due to the dual role of B cells in HHV-8 infection, both as virus reservoir and as agents of humoral immune control, we analyzed the subset distribution and the functional state of peripheral blood B cells in HHV-8-infected individuals with and without cKS. Methodology/Principal Findings Circulating B cells and their subsets were analyzed by 6-color flow cytometry in the following groups: 1- patients HHV-8 positive with classic KS (cKS) (n = 47); 2- subjects HHV-8 positive and cKS negative (HSP) (n = 10); 3- healthy controls, HHV-8 negative and cKS negative (HC) (n = 43). The number of B cells belonging to the preimmune/natural effector compartment, including transitional, pre-naïve, naïve and MZ-like subsets, was significantly higher among HHV-8 positive subjects, with or without cKS, while was comparable to healthy controls in the antigen-experienced T-cell dependent compartment. The increased number of preimmune/natural effector B cells was associated with increased resistance to spontaneous apoptosis, while it did not correlate with HHV-8 viral load. Conclusions/Significance Our results indicate that long-lasting HHV-8 infection promotes an imbalance in peripheral B cell subsets, perturbing the equilibrium between earlier and later steps of maturation and activation processes. This observation may broaden our understanding of the complex interplay between viral and immune factors leading HHV-8-infected individuals to develop HHV-8-associated malignancies.