The host immune response contributes to Haemophilus influenzae virulence

SummaryBackgroundThere 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).ResultsNTHi 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.ConclusionResults suggest that the individual immune reactivity might be an important predictor for the clinical outcome (exacerbation vs. no exacerbation) following NTHi infection

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

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. 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. 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. The positivity rate of TV was low ( <2%) and comparable in all three populations studied. We found no association between TV and CT infectio