Protection of chickens vaccinated with combinations of commercial live infectious bronchitis vaccines containing Massachusetts, Dutch and QX-like serotypes against challenge with virulent infectious bronchitis viruses 793B and IS/1494/06 Israel variant 2

Infectious bronchitis virus (IBV) is a coronavirus which affects chickens of all ages. IBV mainly causes respiratory disease but can also result in reduced weight gain, reduced egg production, increased frequency of abnormal eggs and increased rates of mortality. Vaccination is the most important way to control the disease. Nevertheless, novel strains of infectious bronchitis (IB) continue to emerge in the field. In order to respond promptly, combinations of existing IB vaccines are frequently tested to see whether they can provide cross-protection. The efficacy of a combination of vaccines based on Massachusetts, Dutch and QX-like IB strains against emerging IB Israel variant 2 and IB 793B strains was assessed by means of four challenge studies. At least 80% of the birds vaccinated with IB H120 (Mass type) combined with IB D274 (Dutch type) followed by a QX-like IB vaccine booster or vaccinated with a combination of IB H120, IB D274 and QX-like IB were protected against a challenge with IB 793B. In addition, IB 1263 (Mass type) boosted by QX-like IB showed an 85% protection following challenge with IB 793B. A combination of IB H120 and IB D274 boosted by QX-like IB vaccine conferred 70% protection whilst H120 and IB D274 combination on its own showed 61.1% protection against Israel variant 2 challenge. IB 1263 boosted by a QX-like IB vaccine showed 50% protection against IB Israel variant 2. Therefore, it can be concluded that a combination of the IB H120, IB D274 and QX-like IB confers broad protection against different non-related virulent IB strains.

The administration of probiotics and synbiotics in immune compromised adults: is it safe?

This study aimed to systematically evaluate safety of probiotics and synbiotics in immune compromised adults (≥18 years). Safety was analysed using the Common Terminology Clinical Adverse Events (CTCAE version 4.0) classification, thereby providing an update on previous reports using the most recent available clinical data (2008-2013). Safety aspects are represented and related to number of participants per probiotic strain/culture, study duration, dosage, clinical condition and selected afflictions. Analysis of 57 clinical studies indicates that probiotic and/or synbiotic administration in immune compromised adults is safe with regard to the current evaluated probiotic strains, dosages and duration. Individuals were considered immune compromised if HIV-infected, critically ill, underwent surgery or had an organ- or an autoimmune disease. There were no major safety concerns in the study, as none of the serious adverse events (AE)s were related, or suspected to be related, to the probiotic or synbiotic product and the study products were well tolerated. Overall, AEs occurred less frequent in immune compromised subjects receiving probiotics and/or synbiotics compared to the control group. In addition, the results demonstrated a flaw in precise reporting and classification of AE in most studies. Furthermore, generalisability of conclusions are greatly limited by the inconsistent, imprecise and potentially incomplete reporting as well as the variation in probiotic strains, dosages, administration regimes, study populations and reported outcomes. We argue that standardised reporting on adverse events (CTCAE) in 'food' studies should be obligatory, thereby improving reliability of data and re-enforcing the safety profile of probiotics.

Safety of probiotics and synbiotics in children under 18 years of age

This study aimed to systematically evaluate safety of probiotics and synbiotics in children ageing 0-18 years. This study is the third and final part in a safety trilogy and an update is provided using the most recent available clinical data (2008-2013) by means of the Common Terminology Clinical Adverse Events (CTCAE version 4.0) classification. Safety aspects are represented and related to number of participants per probiotic strain/culture, study duration, dosage, clinical condition and selected afflictions. Analysis of 74 clinical studies indicated that probiotic and/or synbiotic administration in children is safe with regard to the specific evaluated strains, dosages and duration. The population of children include healthy, immune compromised and obese subjects, as well as subjects with intestinal disorders, infections and inflammatory disorders. This study revealed no major safety concerns, as the adverse events (AEs) were unrelated, or not suspected to be related, to the probiotic or synbiotic product. In general the study products were well tolerated. Overall, AEs occurred more frequent in the control arm compared to children receiving probiotics and/or synbiotics. Furthermore, the results indicate inadequate reporting and classification of AEs in the majority of the studies. In addition, generalizability of conclusions are greatly limited by the inconsistent, imprecise and potentially incomplete reporting as well as the variation in probiotic strains, dosages, administration regimes, study populations and reported outcomes.

The impact of practice guidelines in the management of Barrett esophagus: a national prospective cohort study of physicians

BACKGROUND

Surveillance of patients with Barrett esophagus (BE) is recommended to detect dysplasia and early cancer. In 1998, practice guidelines for the surveillance of patients with BE were developed under the auspices of the American College of Gastroenterology (ACG). Our objective is to assess physicians' awareness of agreement with and adherence to these guidelines.

METHODS

A national prospective cohort study of practicing gastroenterologists who completed a self-administered questionnaire containing case studies prior to the release of the guidelines and another survey 18 months later. Analysis of adherence to the guidelines was done using the McNemar chi(2) test.

RESULTS

Of the 154 gastroenterologists (66%) who responded to the follow-up survey, more than half (55%) were aware of the guidelines, and members of the ACG were more likely to know of their existence than nonmembers (61% vs 38%; P =.01). Overall, about 27% of physicians reported practicing in accordance with the guidelines at baseline; adherence increased modestly to 38% in the 18-month follow-up (P =.04) and was inversely related to fee-for-service reimbursement. Awareness was not associated with an increased likelihood of adherence, but agreement with the guidelines was strongly correlated with adherence (P<.001). The most frequent reasons for disagreement were concerns about liability, cancer risk, and inadequate evidence.

CONCLUSIONS

Awareness of the guidelines published by the ACG was low. Guideline awareness did not predict adherence. Improvement in guideline adherence will require steps beyond mere dissemination and promotion. Addressing disagreements about liability, disease risk, and scientific evidence as well as restructuring payment incentives may help achieve optimal practice.

A bacteriophage lambda-based genetic screen for characterization of the activity and phenotype of the human immunodeficiency virus type 1 protease

Human immunodeficiency virus type 1 (HIV-1) resistance to antiretroviral drugs is the main cause of patient treatment failure. Despite the problems associated with interpretation of HIV-1 resistance testing, resistance monitoring should help in the rational design of initial or rescue antiretroviral therapies. It has previously been shown that the activity of the HIV-1 protease can be monitored by using a bacteriophage lambda-based genetic assay. This genetic screening system is based on the bacteriophage lambda regulatory circuit in which the viral repressor cI is specifically cleaved to initiate the lysogenic to lytic switch. We have adapted this simple lambda-based genetic assay for the analysis of the activities and phenotypes of different HIV-1 proteases. Lambda phages that encode HIV-1 proteases either from laboratory strains (strain HXB2) or from clinical samples are inhibited in a dose-dependent manner by the HIV-1 protease inhibitors indinavir, ritonavir, saquinavir, and nelfinavir. Distinct susceptibilities to different drugs were also detected among phages that encode HIV-1 proteases carrying different resistance mutations, further demonstrating the specificity of this assay. Differences in proteolytic processing activity can also be directly monitored with this genetic screen system since two phage populations compete in culture with each other until one phage outgrows the other. In summary, we present here a simple, safe, and rapid genetic screening system that may be used to predict the activities and phenotypes of HIV-1 proteases in the course of viral infection and antiretroviral therapy. This assay responds appropriately to well-known HIV-1 protease inhibitors and can be used to search for new protease inhibitors.

Prevalence and route of transmission of infection with a novel DNA virus (TTV), hepatitis C virus, and hepatitis G virus in patients infected with HIV

OBJECTIVES

To evaluate the prevalence, route of transmission and clinical significance that current co-infection with TT virus (TTV), hepatitis C virus (HCV), and hepatitis G virus (HGV) have in HIV-1-infected patients.

DESIGN

Presence of TTV, HCV, and HGV was analyzed in plasma samples from 160 HIV-1-infected patients with parenteral (38 intravenous drug users [IVDUs] and 41 patients with hemophilia) or sexual (39 homosexuals and 42 heterosexuals) risk of exposure, and in 168 volunteer blood donors. Alanine aminotransferase (ALT) levels and CD4+ counts were also analyzed.

METHODS

HCV and HGV RNA were detected by specific reverse transcriptase (RT) nested polymerase chain reaction (PCR) and TTV DNA by specific heminested PCR.

RESULTS

TTV DNA was detected in 39% of the patients and in 14% of the volunteer blood donors. HCV and HGV infections were detected in 42% and in 14% of the patients, and in 0% and 3% of the blood donors, respectively. Prevalences of TTV and HCV infection were higher among patients with parenteral (62% and 68%) than in those with sexual (17% and 16%) risk of exposure. A higher prevalence of TTV infection (but not of HCV or HGV infection) was observed among patients with hemophilia (76%) than IVDUs (47%), and among homosexuals (26%) than among heterosexuals (10%). Abnormal ALT levels were related with the presence of HCV infection, independently of the detection of TTV DNA. TTV infection did not seem to alter the levels of CD4+ T cells.

CONCLUSIONS

Prevalence of current TTV infection is high among HIV-infected patients with parenteral risk of exposure, but TTV is also transmitted through sexual routes; detection of TTV does not seem to influence the clinical or immune status of HIV-infected patients.

Emergence and genetic evolution of HIV-1 variants with mutations conferring resistance to multiple reverse transcriptase and protease inhibitors

The emergence of genotypic resistance in protease and reverse transcriptase (RT) gene regions was longitudinally evaluated in plasma samples from a group of 12 HIV-1-infected patients treated with different combination of antiretroviral therapies and selected on the basis of their clinical failure. Complex mutational patterns in the reverse transcriptase gene were observed. In particular, combinations of AZT (41L, 67N, 70R, 210W, and 219Q/E) and 3TC (184M) were seen in 10 patients. Two patients presented codon 151 multinucleoside analogue resistance (MNR). Additionally, seven patients harbored RT nonnucleoside analogue-related resistance substitutions (98G, 103N, and 181C). Multiple protease-selected mutations were found in each patient with an average of six substitutions per patient, with 10I/F/V, 63P, 71V, 82A/T, 84V, and 90M being the most prevalent substitutions. Overall, these results showed that for most patients virological failure was coupled with detectable genotypic resistance. Furthermore, most patients exhibited genotypic resistance to almost all available anti-HIV-1 drugs. The high viral loads found in most patients at the end of the study suggest that the replication of these multidrug resistant viruses are not severely compromised. Phylogenetic analysis of these pol sequences revealed that a specific HIV-1 genotype prone to develop multidrug resistance was not found.

Human immunodeficiency virus type 1 genetic evolution in patients with prolonged suppression of plasma viremia

Treatment of human immunodeficiency virus type 1 (HIV-1)-infected patients with combination drug regimens results in a reduction of plasma viral load to levels below the limit of detection. To investigate the genomic fluctuations in HIV-1 populations from long-term responders to antiviral therapies we analyzed the viral sequence evolution of env and pol genes from sequential peripheral blood mononuclear cell (PBMC) DNA samples of three infected patients. Analyses of sequences covering the V3 and flanking env regions obtained from blood samples at the beginning of the therapy and at 14 or 24 months from baseline revealed that HIV-1 quasispecies continue to evolve in the three patients following combination antiretroviral therapy. Minor drug-resistant mutant subpopulations were also searched for and found in one patient. Interestingly, no minor resistant subpopulations were found in the other two patients despite the fact that they showed evidence of ongoing viral replication. Finally, the genetic analysis of the env gene shows a reduction in PBMC env viral population diversity after long-term response to the therapy in all the patients analyzed.