Low positivity rate after systematic screening for Trichomonas vaginalis in three patient cohorts from general practitioners, STI clinic and a national population-based chlamydia screening study.

OBJECTIVE: The goal of this multi-cohort study is to investigate the positivity rate of Trichomonas vaginalis (TV) among three distinct Dutch patient populations and its relation with Chlamydia trachomatis (CT) positivity. Few studies have been performed in Europe where TV positivity rate seems to be low. Additionally, the majority of earlier studies have focused on high risk or specific populations. METHODS: A random selection of men and women from a national population-based chlamydia screening, attendees of a sexually transmitted infections (STI) clinic and a non-selected population from general practitioners (GPs) were systematically screened for TV and CT using PCR. The associations among TV and CT co-infection, age and gender were studied. RESULTS: A total of 2079 individuals were studied. A TV positivity rate of 1.5% was observed in the medium risk GP cohort followed by 0.7% in the low risk population-based cohort and 0.6% in the high risk STI clinic. TV was found in 0.7% of CT positives and a similar 1.1% among CT negatives. All TV positive individuals in this study were women. CONCLUSIONS: The positivity rate of TV was low (<2%) and comparable in all three populations studied. We found no association between TV and CT infection.

Antimicrobial resistance among respiratory Haemophilus influenzae isolates from pulmonology services over a six-year period.

BACKGROUND: Respiratory tract infections (RTI) are frequently caused by Haemophilus influenzae. Widespread antibacterial resistance among respiratory microorganisms complicates empirical RTI treatment. Therefore, national data on antibiotic resistance for H. influenzae are important for guiding optimal antibiotic choice. METHODS: The antibiotic susceptibility of H. influenzae strains isolated from respiratory specimens of patients admitted to the pulmonology services between 2005 and 2010 was assessed. Isolates were collected annually from 13 hospitals in the Netherlands as part of the national intramural antimicrobial resistance surveillance performed by the Dutch Working Group on Antibiotic Policy (SWAB). Breakpoints for resistance were in accordance with the criteria of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Trend analysis was performed using logistic regression analysis. RESULTS: In total, 1606 H. influenzae strains were analyzed. The prevalence of antibiotic resistance to amoxicillin, co-amoxiclav, doxycycline, co-trimoxazole, and clarithromycin was stable over the 6-y period, and there was a trend towards a decrease in the prevalence of beta-lactamase-producing isolates. Regarding prevalences, no significant trends were observed. CONCLUSIONS: Our study showed no significant changes in antibiotic resistance for H. influenzae isolated at different hospitals in the Netherlands over a 6-y period. Regular surveillance remains important in controlling the prevalence of resistance, since actual resistance data should be taken into account when the choice of an empiric antibiotic is made.

The host immune response contributes to Haemophilus influenzae virulence.

BACKGROUND: There is compelling evidence that infections with non-typeable Haemophilus influenzae (NTHi) are associated with exacerbations in COPD patients. However, NTHi has also been isolated frequently during clinically stable disease. In this study we tested the hypothesis that genetically distinct NTHi isolates obtained from COPD patients differ in virulence which could account for dissimilarities in the final outcome of an infection (stable vs. exacerbation). RESULTS: NTHi isolates (n = 32) were obtained from stable COPD patients, or during exacerbations. Genetically divergent NTHi isolates were selected and induction of inflammation was assessed as an indicator of virulence using different in vitro models. Despite marked genomic differences among NTHi isolates, in vitro studies could not distinguish between NTHi isolates based on their inflammatory capacities. Alternatively, when using a whole blood assay results demonstrated marked inter-, but not intra-individual differences in cytokine release between healthy volunteers irrespective of the origin of the NTHi isolate used. CONCLUSION: Results suggest that the individual immune reactivity might be an important predictor for the clinical outcome (exacerbation vs. no exacerbation) following NTHi infection.

Interferon-ß induces a long-lasting antiviral state in human respiratory epithelial cells.

OBJECTIVES: Interferon-ß (IFNß) induces strong antiviral effects and is therefore an attractive agent to prevent or reduce the incidence of virus-mediated exacerbations in asthmatic or chronic obstructive pulmonary disease (COPD) patients. We therefore investigated the effects of prophylactic IFNß on respiratory epithelial cells infected with rhinovirus (RV). METHODS: A549 cells and primary bronchial epithelial cells (PBECs) were exposed for 18 h to IFNß. Then, IFNß was either removed or maintained in the supernatant for the rest of the experiment and cells were infected with RV-1B at t = 0 or 72 h after the initial exposure to IFNß. RESULTS: Viral RNA levels were decreased in both cell types. Furthermore, both viral RNA and infectious virus levels in the supernatant of infected A549 cells were still significantly reduced at 72 h after removal of IFNß. This pronounced antiviral pre-treatment effect was associated with increased expression of the antiviral genes IFN-stimulated protein of MR15000 (ISG15) and Myxovirus resistance 1 (Mx1) and the effect was maintained even when IFNß levels in the supernatant of A549 cells were undetectable. CONCLUSIONS: These data show that IFNß has not only a strong, but also a long-lasting protective effect against RV infection of respiratory epithelium.

Performance of cobas® 4800 and m2000 real-time™ assays for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in rectal and self-collected vaginal specimen.

A prospective, multicenter trial was designed to compare the performance characteristics of the cobas® 4800 (Roche Diagnostics, Indianapolis, IN, USA) and m2000 real-time™ (Abbott Molecular Inc., Des Plaines, IL, USA) assays for detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) in rectal and self-collected vaginal swabs. Rectal (n = 234) or self-collected vaginal swabs (n = 687) were obtained from consenting individuals visiting their general practitioners, dermatologists, gynecologists, sexually transmitted disease clinics, or family planning centers from May 2010 to February 2011. High concordance rates (≥96%) were observed between the cobas® 4800 and m2000 real-time™ assays for CT/NG detection in both rectal and self-collected vaginal swabs. The performance profiles confirm the usefulness of both kinds of swab types for CT and NG detection using described nucleic acid amplification tests assays. Based on this study, rectal and self-collected vaginal swabs offer a noninvasive alternative, which may improve screening for CT and NG infections.

CpG and poly(I:C) stimulation of dendritic cells and fibroblasts limits herpes simplex virus type 1 infection in an IFNß-dependent and -independent way.

Viral activation of toll-like receptors (TLRs) on dendritic cells (DCs) leads to production of various cytokines, including antiviral type I interferons (IFNs). Synthetic ligands specific for TLRs are also able to induce the production of type I IFNs (IFNα/ß) by DCs, suggesting that these ligands have potential as antiviral drugs. In this in vitro study we extensively investigated the antiviral activity of various TLR ligands. Mouse bone marrow (BM) cells were differentiated into plasmacytoid and conventional DCs (pDCs and cDCs), stimulated with various TLR ligands and tested the antiviral abilities of collected supernatants in an in vitro herpes simplex virus type 1 (HSV-1) infection model. We observed a significant IFNß-, (but not IFNα-) dependent reduction in HSV-1 infection when a mixed pDC/cDC population was stimulated with the TLR9 ligand CpG. In the absence of pDCs, TLR stimulation resulted in less pronounced antiviral effects. The most pronounced antiviral effect was observed when both DC subsets were stimulated with poly(I:C). A similar noticeable antiviral effect was observed when fibroblasts (L929 cells) were stimulated directly with poly(I:C). These poly(I:C)-mediated antiviral effects were only partially IFNß-mediated and probably TLR independent. These data demonstrate that TLR ligands are not only able to produce type I IFN but can indeed act as antiviral drugs. In particular poly(I:C), which exerts its antiviral effects even in the absence of DCs, may become a promising drug e.g. to prevent respiratory infections by topical intranasal application.