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Contains fulltext : 247661.pdf (Publisher’s version ) (Open Access)

Contains fulltext : 232499.pdf (Publisher’s version ) (Open Access), OBJECTIVES: Antimicrobial stewardship (AMS) has established its importance for inpatient care. AMS is, however, also urgently needed in emergency departments (ED), where many antimicrobial prescriptions are initiated. It is currently unclear what metrics stewardship teams can use to measure and improve the appropriateness of antimicrobial prescription in the ED. In this study we develop quality indicators (QIs) for antimicrobial use in the ED. METHODS: A RAND-modified Delphi procedure was used to develop a set of QIs applicable to adult patients who present at the ED with a potential infection. First, pragmatically using two recent papers of the international expert-group DRIVE-AB, potential ED-specific QIs for appropriate antimicrobial use were retrieved. Thereafter, an international multidisciplinary expert panel appraised these QIs during two questionnaire rounds with a meeting in between. RESULTS: Thirty-three potential QIs were extracted from the DRIVE-AB papers. After appraisal by 13 experts, 22 QIs describing appropriate antimicrobial use in the ED were selected. These indicators provide recommendations within five domains: stewardship prerequisites (six QIs); diagnostics (one QI); empirical treatment (ten QIs); documentation of information (four QIs); and patient discharge (one QI). CONCLUSIONS: We pragmatically developed a set of 22 QIs that can be used by stewardship teams to measure the appropriateness of antimicrobial prescription in the ED. There is probably room for additional QI development to cover all key aspects of AMS in the ED. Measuring QIs can be a first step for stewardship teams to, in collaboration with ED professionals, choose targets for improvement and optimize antimicrobial use.

Contains fulltext : 232371.pdf (Publisher’s version ) (Open Access), BACKGROUND: Emergency departments (EDs) are the entrance gates for patients presenting with infectious diseases into the hospital, yet most antimicrobial stewardship programmes are primarily focused on inpatient management. With equally high rates of inappropriate antibiotic use, the ED is a frequently overlooked yet important unit for targeted antimicrobial stewardship (AMS) interventions. OBJECTIVES: We aimed to (a) describe the specific aspects of antimicrobial stewardship in the ED and (b) summarize the findings from improvement studies that have investigated the effectiveness of antimicrobial stewardship interventions in the ED setting. SOURCES: (a) a PubMed search for 'antimicrobial stewardship' and 'emergency department', and (b) published reviews on effectiveness combined with publications from the first source. CONTENT: (a) An in depth analysis of selected publications provided four key antimicrobial use processes typically performed by front-line healthcare professionals in the ED: making a (tentative) clinical diagnosis, starting empirical therapy based on that diagnosis, performing microbiological tests before starting that therapy and following up patients who are discharged from the ED. (b) Further, we discuss the literature on improvement strategies in the ED focusing on guidelines and clinical pathways and multifaceted improvement strategies. We also summarize the evidence of microbiologic culture review. IMPLICATIONS: Based on our review of the literature, we describe four essential elements of antimicrobial use in the ED. Studying the various interventions targeting these care processes, we have found them to be of a variable degree of success. Nonetheless, while there is a paucity of AS studies specifically targeting the ED, there is a growing body of evidence that AS programmes in the ED are effective with modifications to the ED setting. We present key questions for future research.

Contains fulltext : 195881.pdf (publisher's version ) (Closed access)

Contains fulltext : 193383.pdf (publisher's version ) (Open Access), Approximately 20% of patients with acute Q fever develop Q fever fatigue syndrome (QFS), a debilitating fatigue syndrome. This study further investigates the role of C. burnetii-specific IFNgamma, but also IL-2, CXCL9, CXCL10, and CXLC11 production in QFS patients. C. burnetii-specific IFNy, IL-2, CXCL9, CXCL10, and CXCL11 production were tested in ex vivo stimulated whole blood of QFS patients who recovered from their complaints (n = 8), QFS patients with persisting complaints (n = 27), and asymptomatic Q fever seropositive controls (n = 10). With the exclusion of one outlier, stimulation with C. burnetii revealed significantly higher IFNy and CXCL10 production in QFS patients with persisting complaints (medians 288.0 and 176.0 pg/mL, respectively) than in QFS patients who recovered from their complaints (medians 93.0 and 85.5 pg/mL, respectively) (p = 0.041 and 0.045, respectively). No significant differences between groups were found for C. burnetii-specific IL-2, CXCL9, and CXCL11 production. These findings point towards a difference in cell-mediated immunity in QFS patients with persisting complaints compared to those who recovered from their complaints. Such a difference may aid to eventually diagnose QFS more objectively and might serve as an indicator of its underlying etiology.

Contains fulltext : 177306.pdf (publisher's version ) (Open Access), BACKGROUND: In the aftermath of the largest Q fever outbreak in the world, diagnosing the potentially lethal complication chronic Q fever remains challenging. PCR, Coxiella burnetii IgG phase I antibodies, CRP and 18F-FDG-PET/CT scan are used for diagnosis and monitoring in clinical practice. We aimed to identify and test biomarkers in order to improve discriminative power of the diagnostic tests and monitoring of chronic Q fever. METHODS: We performed a transcriptome analysis on C. burnetii stimulated PBMCs of 4 healthy controls and 6 chronic Q fever patients and identified genes that were most differentially expressed. The gene products were determined using Luminex technology in whole blood samples stimulated with heat-killed C. burnetii and serum samples from chronic Q fever patients and control subjects. RESULTS: Gene expression of the chemokines CXCL9, CXCL10, CXCL11 and CCL8 was strongly up-regulated in C. burnetii stimulated PBMCs of chronic Q fever patients, in contrast to healthy controls. In whole blood cultures of chronic Q fever patients, production of all four chemokines was increased upon C. burnetii stimulation, but also healthy controls and past Q fever individuals showed increased production of CXCL9, CXCL10 and CCL8. However, CXCL9 and CXCL11 production was significantly higher for chronic Q fever patients compared to past Q fever individuals. In addition, CXCL9 serum concentrations in chronic Q fever patients were higher than in past Q fever individuals. CONCLUSION: CXCL9 protein, measured in serum or as C. burnetii stimulated production, is a promising biomarker for the diagnosis of chronic Q fever.

Contains fulltext : 169718.pdf (publisher's version ) (Closed access), OBJECTIVES: Q fever is caused by Coxiella burnetii, an intracellular bacterium that infects phagocytes. The aim of the present study was to investigate whether the C. burnetii-induced IFN-gamma response is defective in chronic Q fever patients. METHODS: IFN-gamma was measured in supernatants of C. burnetii-stimulated peripheral blood mononuclear cells (PBMCs) of 17 chronic Q fever patients and 17 healthy individuals. To assess IFN-gamma responses, expression profiles of IFN-gamma-induced genes in C. burnetii-stimulated PBMCs were studied in six patients and four healthy individuals. Neopterin was measured in PBMC supernatants (of eight patients and four healthy individuals) and in sera (of 21 patients and 11 healthy individuals). In a genetic association study, polymorphisms in genes involved in the Th1-cytokine response were analysed in a cohort of 139 chronic Q fever patients and a cohort of 220 control individuals with previous exposition to C. burnetii. RESULTS: IFN-gamma production by C. burnetii-stimulated PBMCs from chronic Q fever patients was significantly higher than in healthy controls. Many IFN-gamma response genes were strongly upregulated in PBMCs of patients. Neopterin levels were significantly higher in PBMC supernatants and sera of patients. The IL12B polymorphisms rs3212227 and rs2853694 were associated with chronic Q fever. CONCLUSIONS: IFN-gamma production, as well as the response to IFN-gamma, is intact in chronic Q fever patients, and even higher than in healthy individuals. Polymorphisms in the IL-12p40 gene are associated with chronic Q fever. Thus, a deficiency in IFN-gamma responses does not explain the failure to clear the infection. The genetic data suggest, however, that the IL-12/IFN-gamma pathway does play a role.

Contains fulltext : 165674.pdf (publisher's version ) (Closed access), As part of the Human Functional Genomics Project, which aims to understand the factors that determine the variability of immune responses, we investigated genetic variants affecting cytokine production in response to ex vivo stimulation in two independent cohorts of 500 and 200 healthy individuals. We demonstrate a strong impact of genetic heritability on cytokine production capacity after challenge with bacterial, fungal, viral, and non-microbial stimuli. In addition to 17 novel genome-wide significant cytokine QTLs (cQTLs), our study provides a comprehensive picture of the genetic variants that influence six different cytokines in whole blood, blood mononuclear cells, and macrophages. Important biological pathways that contain cytokine QTLs map to pattern recognition receptors (TLR1-6-10 cluster), cytokine and complement inhibitors, and the kallikrein system. The cytokine QTLs show enrichment for monocyte-specific enhancers, are more often located in regions under positive selection, and are significantly enriched among SNPs associated with infections and immune-mediated diseases. PAPERCLIP.

Contains fulltext : 172623.pdf (publisher's version ) (Closed access), Coxiella burnetii, the causative agent of Q fever, is recognized by TLR2. TLR10 can act as an inhibitory receptor on TLR2-derived immune responses. Therefore, we investigated the role of TLR10 on C. burnetii-induced cytokine production and assessed whether genetic polymorphisms in TLR10 influences the development of chronic Q fever. HEK293 cells, transfected with TLR2, TLR10 or TLR2/TLR10, and human peripheral blood mononuclear cells (PBMCs) in the presence of anti-TLR10, were stimulated with C. burnetii. In both assays, the absence of TLR10 resulted in increased cytokine responses after C. burnetii stimulation. In addition, the effect of single nucleotide polymorphisms (SNPs) in TLR10 was examined in healthy volunteers whose PBMCs were stimulated with C. burnetii Nine Mile or the Dutch outbreak isolate C. burnetii 3262. Individuals bearing SNPs in TLR10 displayed increased cytokine production upon C. burnetii 3262 stimulation. Furthermore, 139 chronic Q fever patients and 220 controls were genotyped for TLR10 N241H, I775V and I369L. None of these polymorphisms were associated with increased susceptibility to chronic Q fever. In conclusion, TLR10 has an inhibitory effect on in vitro cytokine production by C. burnetii, but the presence of TLR10 polymorphisms does not lead to an increased risk of developing chronic Q fever.

Contains fulltext : 171072.pdf (publisher's version ) (Closed access), OBJECTIVES: Whether immunological mechanisms underlie Q-fever fatigue syndrome (QFS) remains unclear. For acute Q-fever, the antigen-specific interferon-gamma (IFNgamma) response may be a useful tool for diagnosis, and the IFNgamma/interleukin(IL)-2 production ratio may be a marker for chronic Q-fever and treatment monitoring. Here we explored the specific IFNgamma production and IFNgamma/IL-2 ratio in QFS patients. METHODS: IFNgamma and IL-2 production were tested in ex-vivo stimulated whole blood of QFS patients (n = 20), and compared to those previously determined in seropositive controls (n = 135), and chronic Q-fever patients (n = 28). Also, the correlation between patient characteristics and IFNgamma, IL-2, and IFNgamma/IL-2 ratio was determined. RESULTS: QFS patients were younger (p < 0.001), but gender distribution was similar to seropositive controls and chronic Q-fever patients. Coxiella burnetii Nine Mile stimulation revealed a higher IFNgamma production in QFS (median 319.5 pg/ml) than in seropositive controls (120 pg/ml, p < 0.01), but comparable to chronic Q-fever (2846 pg/ml). The IFNgamma/IL-2 ratio was similar to that in seropositive controls, but lower than in chronic Q-fever patients (p < 0.01). Symptom duration was positively correlated with IL-2 production, and negatively correlated with the IFNgamma/IL-2 ratio. CONCLUSIONS: These results point to an altered cell-mediated immunity in QFS, and suggest a different immune response than in chronic Q-fever.

Contains fulltext : 172211.pdf (publisher's version ) (Open Access), BACKGROUND: Chronic Q fever is a rare infection, which mainly manifests as endocarditis, infection of vascular prostheses or aortic aneurysms. We present the case of a 74-year-old immunocompromised man with a haematologically disseminated Coxiella burnetii infection, which has never been reported before. CASE REPORT: He was diagnosed with a chronic Q fever infection of an aneurysm with an endovascular prosthesis in 2015, but he died despite optimal treatment. Autopsy revealed a disseminated C. burnetii infection, confirmed by a positive PCR on samples from several organs. Retrospectively, he already had complaints and signs of inflammation since 2012, for which he had already been admitted in February 2014. At that time, Q fever diagnostics using PCR, complement fixation assay, and enzyme-linked immunosorbent assay on serum were all negative. In retrospect however, retesting available samples from February 2014 using immunofluorescence assay (IFA) already revealed serology compatible with chronic Q fever. CONCLUSION: Clinicians should be aware of this silent killer, especially in case of risk factors, and perform an appropriate diagnostic work-up for Q fever including IFA serology and PCR.

Contains fulltext : 155344.pdf (publisher's version ) (Closed access), BACKGROUND: Q fever is an infection caused by Coxiella burnetii. Persistent infection (chronic Q fever) develops in 1%-5% of patients. We hypothesize that inefficient recognition of C. burnetii and/or activation of host-defense in individuals carrying genetic variants in pattern recognition receptors or adaptors would result in an increased likelihood to develop chronic Q fever. METHODS: Twenty-four single-nucleotide polymorphisms in genes encoding Toll-like receptors, nucleotide-binding oligomerization domain-like receptor-2, alphavbeta3 integrin, CR3, and adaptors myeloid differentiation primary response protein 88 (MyD88), and Toll interleukin 1 receptor domain-containing adaptor protein (TIRAP) were genotyped in 139 patients with chronic Q fever and in 220 controls with cardiovascular risk-factors and previous exposure to C. burnetii. Associations between these single-nucleotide polymorphisms and chronic Q fever were assessed by means of univariate logistic regression models. Cytokine production in whole-blood stimulation assays was correlated with relevant genotypes. RESULTS: Polymorphisms in TLR1 (R80T), NOD2 (1007fsX1), and MYD88 (-938C>A) were associated with chronic Q fever. No association was observed for polymorphisms in TLR2, TLR4, TLR6, TLR8, ITGAV, ITGB3, ITGAM, and TIRAP. No correction for multiple testing was performed because only genes with a known role in initial recognition of C. burnetii were included. In the whole-blood assays, individuals carrying the TLR1 80R-allele showed increased interleukin 10 production with C. burnetii exposure. CONCLUSIONS: Polymorphisms in TLR1 (R80T), NOD2 (L1007fsX1), and MYD88 (-938C>A) are associated with predisposition to development of chronic Q fever. For TLR1, increased interleukin 10 responses to C. burnetii in individuals carrying the risk allele may contribute to the increased risk of chronic Q fever.

Contains fulltext : 153993.pdf (publisher's version ) (Open Access), BACKGROUND: Antibiotic treatment of chronic Q fever is cumbersome and of long duration. To monitor treatment, there is a need for alternative biomarkers. Coxiella burnetii-specific interferon (IFN)-gamma and interleukin (IL)-2 production reflect the type of effector and memory T-cell response. In chronic Q fever, C. burnetii-specific IFN-gamma production is higher and IL-2 production is lower than in individuals with past Q fever. Here we explore whether C. burnetii-specific IFN-gamma and IL-2 production correlate to treatment response. METHODS: We studied the longitudinal C. burnetii-specific IFN-gamma/IL-2 ratio in fifteen proven chronic Q fever patients. All patients were followed for at least 18 months during antibiotic treatment. Treatment was considered successful when clinical recovery was observed, a positive PCR for C. burnetii DNA in blood became persistently negative, anti-phase I IgG showed a fourfold decrease or more, and imaging techniques showed disappearance of infectious foci. RESULTS: Overall, the IFN-gamma/IL-2 ratio declined when patients experienced a successful treatment outcome. When treatment failed, IFN-gamma/IL-2 ratios did not significantly decrease. The median (+/-IQR) slope of the longitudinal IFN-gamma/IL-2 ratio with successful treatment was -2.10 (-7.02 to -0.06), and -0.15 (-1.13 to 0.25) with unsuccessful treatment (P = 0.19). Q fever endocarditis patients had higher IFN-gamma/IL-2 ratios than patients with endovascular infections. CONCLUSION: We propose that the IFN-gamma/IL-2 ratio can be used as an additional biomarker for monitoring chronic Q fever treatment, with declining ratios being indicative of successful treatment.

Contains fulltext : 154899.PDF (publisher's version ) (Open Access), BACKGROUND: In 2011, a unique Q fever vaccination campaign targeted people at risk for chronic Q fever in the southeast of the Netherlands. General practitioners referred patients with defined cardiovascular risk-conditions (age >15 years). Prevalence rates of those risk-conditions were lacking, standing in the way of adequate planning and coverage estimation. We aimed to obtain prevalence rates retrospectively in order to estimate coverage of the Q fever vaccination campaign. METHODS: With broad search terms for these predefined risk-conditions, we extracted patient-records from a large longitudinal general-practice research-database in the Netherlands (IPCI-database). After validation of these records, obtained prevalence rates (stratified for age and sex) extrapolated to the Q fever high-incidence area population, gave an approximation of the size of the targeted patient-group. Coverage calculation addressed people actually screened by a pre-vaccination Q fever skin test and serology (coverage) and patients referred by their general practitioners (adjusted-coverage) in the 2011 campaign. RESULTS: Our prevalence estimate of any risk-condition was 3.1% (lower-upper limits 2.9-3.3%). For heart valve defects, aorta aneurysm/prosthesis, congenital anomalies and endocarditis, prevalence was 2.4%, 0.6%, 0.4% and 0.1%, respectively. Estimated number of eligible people in the Q fever high-incidence area was 11,724 (10,965-12,532). With 1330 people screened for vaccination, coverage of the vaccination campaign was 11%. For referred people, the adjusted coverage was 18%. Coverage was lowest among the very-old and highest for people aged 50-70 years. CONCLUSION: The estimated coverage of the vaccination campaign was limited. This should be interpreted in the light of the complexity of this target-group with much co-morbidity, and of the vaccine that required invasive pre-vaccination screening. Calculation of prevalence rates of risk-conditions based on the IPCI-database was

Contains fulltext : 153819.pdf (publisher's version ) (Closed access), BACKGROUND: Infection with Coxiella burnetii can lead to acute and chronic Q fever. Toll-like receptor 1 (TLR1), TLR2, TLR4, TLR6, nucleotide-binding oligomerization domain receptor 1 (NOD1), NOD2, and the mitogen-activated protein kinases are central in the innate immune response against microorganisms, but little is known about their role in the recognition of C. burnetii in humans. METHODS: Human peripheral blood mononuclear cells (PBMCs) were stimulated with C. burnetii Nine Mile and the Dutch outbreak isolate C. burnetii 3262. TLRs were inhibited using specific antibodies or antagonists. Additionally, the influence of human polymorphisms in TLRs and Nod-like receptors (NLRs) on C. burnetii-induced cytokine production was assessed. RESULTS: Inhibition of TLR2, p38, JNK, and ERK led to decreased cytokine responses in C. burnetii-stimulated human PBMCs. Humans with polymorphisms in TLR1 and NOD2 had reduced cytokine production, compared with humans with wild-type genotypes, after stimulation. Interestingly, polymorphisms in TLR6 led to decreased cytokine production after C. burnetii 3262 stimulation but not after C. burnetii Nine Mile stimulation. CONCLUSIONS: The TLR1/TLR2 heterodimer and NOD2 are important recognition receptors for the induction of cytokine responses against C. burnetii in humans. Furthermore, an interesting finding was the divergent recognition of C. burnetii Nine Mile and C. burnetii 3262.

Contains fulltext : 155097.pdf (publisher's version ) (Closed access), Coxiella burnetii, a Gram-negative intracellular bacterium, can give rise to Q fever in humans and is transmitted mainly by inhalation of infected aerosols from animal reservoirs. Serology is commonly used to diagnose Q fever, but the early cellular immune response-i.e., C. burnetii-specific interferon gamma (IFN-gamma) production in response to antigen challenge-might be an additional diagnostic. Detection of IFN-gamma responses has been used to identify past and chronic Q fever infections, but the IFN-gamma response in acute Q fever has not been described. By challenging immunocompetent BALB/c mice with aerosols containing phase I C. burnetii, the timing and extent of IFN-gamma recall responses were evaluated in an acute C. burnetii infection. Other cytokines were also measured in an effort to identify other potential diagnostic markers. The data show that after initial expansion of bacteria first in lungs and then in other tissues, the infection was cleared from day 10 onwards as reflected by the decreasing number of bacteria. The antigen-induced IFN-gamma production by splenocytes coincided with emergence of IgM phase II antibodies at day 10 postinfection and preceded appearance of IgG antibodies. This was accompanied by the production of proinflammatory cytokines including interleukin (IL) 6, keratinocyte-derived cytokine, and IFN-gamma-induced protein 10, followed by monocyte chemotactic protein 1, but not by IL-1beta and tumor necrosis factor alpha, and only very low production of the anti-inflammatory cytokine IL-10. These data suggest that analysis of antigen-specific IFN-gamma responses could be a useful tool for diagnosis of acute Q fever. Moreover, the current model of C. burnetii infection could be used to give new insights into immunological factors that predispose to development of persistent infection.

Background: In 2011, a unique Q fever vaccination campaign targeted people at risk for chronic Q fever in the southeast of the Netherlands. General practitioners referred patients with defined cardiovascular risk-conditions (age >15 years). Prevalence rates of those risk-conditions were lacking, standing in the way of adequate planning and coverage estimation. We aimed to obtain prevalence rates retrospectively in order to estimate coverage of the Q fever vaccination campaign. Methods: With broad search terms for these predefined risk-conditions, we extracted patient-records from a large longitudinal general-practice research-database in the Netherlands (IPCI-database). After

Radboud Universiteit Nijmegen, 2 november 2015, Promotores : Meer, J.W.M. van der, Netea, M.G. Co-promotores : Deuren, M. van, Sprong, T., Contains fulltext : 145305.pdf (publisher's version ) (Open Access), Q fever is an infection caused by the bacterium Coxiella burnetii. A large outbreak of Q fever occurred in the Netherlands between 2007 and 2010, in which infected goats and sheep were the source of human infections. In some people, so-called ‘chronic Q fever’ develops, which mainly manifests as endocarditis, infection of vascular prosthesis or aortic aneurysms, or both. We studied the immune response against C. burnetii in blood of healthy individuals, chronic Q fever patients and people with a past Q fever infection. Immune cells of chronic Q fever patients showed an increased production of ‘interferon-gamma’, a key signalling molecule. We concluded that, in contrast to what had generally been assumed, the interferon-gamma mediated immune response is not defect in chronic Q fever. Subsequently, we used the measurement of interferon-gamma production and other cell-signalling molecules (‘cytokines’) in blood in-vitro for diagnostic purposes. We found that these kind of blood tests can accurately detect a past or chronic Q fever infection. This valuable new diagnostic tool is currently being developed to a commercial blood test for Q fever infection. In a screening-study among patients with rheumatoid arthritis (RA) with immunomodulating drugs, we studied the risk for chronic Q fever. We found that RA patients are at increased risk for chronic Q fever compared to the general population. We advised to carefully check for chronic Q fever in these patients when they have been exposed to C. burnetii. We alse studied the unique Q fever vaccination campaign in the Netherlands in 2011, in which 1370 people with increased risk for chronic Q fever were vaccinated. This was the first time worldwide that such a large population at risk was being vaccinated against Q fever. We could conclude that vaccination was safe, but many vaccinees reported local skin reactions. We measured the immune response in blood of vaccinees 6 and 12 months after vaccination and found overall only a

Background In 2011, a unique Q fever vaccination campaign targeted people at risk for chronic Q fever in the southeast of the Netherlands. General practitioners referred patients with defined cardiovascular risk-conditions (age >15 years). Prevalence rates of those risk-conditions were lacking, standing in the way of adequate planning and coverage estimation. We aimed to obtain prevalence rates retrospectively in order to estimate coverage of the Q fever vaccination campaign. Methods With broad search terms for these predefined risk-conditions, we extracted patient-records from a large longitudinal general-practice research-database in the Netherlands (IPCI-database). After validation of these records, obtained prevalence rates (stratified for age and sex) extrapolated to the Q fever high-incidence area population, gave an approximation of the size of the targeted patient-group. Coverage calculation addressed people actually screened by a pre-vaccination Q fever skin test and serology (coverage) and patients referred by their general practitioners (adjusted-coverage) in the 2011 campaign. Results Our prevalence estimate of any risk-condition was 3.1% (lower-upper limits 2.9-3.3%). For heart valve defects, aorta aneurysm/prosthesis, congenital anomalies and endocarditis, prevalence was 2.4%, 0.6%, 0.4% and 0.1%, respectively. Estimated number of eligible people in the Q fever high-incidence area was 11,724 (10,965-12,532). With 1330 people screened for vaccination, coverage of the vaccination campaign was 11%. For referred people, the adjusted coverage was 18%. Coverage was lowest among the very-old and highest for people aged 50-70 years. Conclusion The estimated coverage of the vaccination campaign was limited. This should be interpreted in the light of the complexity of this target-group with much co-morbidity, and of the vaccine that required invasive pre-vaccination screening. Calculation of prevalence rates of risk-conditions based on the IPCI-database was feas

Contains fulltext : 138226.pdf (publisher's version ) (Closed access), The Q fever skin-test is used to measure cell-mediated immunity to Coxiella burnetii in pre-vaccination screening to exclude individuals with pre-existing immunity. We investigated whether this in-vivo test influences subsequent measurements of immune response.We assessed the humoral and cellular immune responses before, and 6 and 12 months after skin-testing in 63 individuals who were not vaccinated because of either a positive skin test or positive serology in screening. IgG anti-C. burnetii antibodies were measured using immune-fluorescence assay (IFA). The cellular immune response was assessed by measuring in-vitro C. burnetii-specific interferon (IFN)-γ production in blood.Of the 35 subjects with a positive skin-test and negative serology, 15/35 (43\%) showed seroconversion at 6 months, and 7/32 (22\%) seropositivity at 12 months. The mean ± SE specific IFN-γ production in this group increased from 185 ± 88 pg/mL (at baseline) to 422 ± 141 pg/mL at 6 months (P = 0.009) and 223 ± 91 pg/mL at 12 months (P = 0.17). Of the 28 subjects with positive serology (and unknown skin test results), 21/28 (75\%) showed an increase in IgG anti-phase I titres at 6 months, and 11/25 (44\%) at 12 months. The mean ± SE specific IFN-γ production was significantly increased at 6 months, but not at 12 months.Q fever skin-testing causes higher antibody titres and higher in-vitro IFN-γ to C. burnetii, and therefore affects subsequent Q fever diagnostics.

Contains fulltext : 138727.pdf (publisher's version ) (Open Access), In humans, infection with Coxiella burnetii, the causative agent of Q fever, leads to acute or chronic infection, both associated with specific clinical symptoms. In contrast, no symptoms are observed in goats during C. burnetii infection, although infection of the placenta eventually leads to premature delivery, stillbirth and abortion. It is unknown whether these differences in clinical outcome are due to the early immune responses of the goats. Therefore, peripheral blood mononuclear cells (PBMCs) were isolated from pregnant goats. In total, 17 goats were included in the study. Six goats remained naive, while eleven goats were infected with C. burnetii. Toll-like receptor (TLR) and cytokine mRNA expression were measured after in vitro stimulation with heat-killed C. burnetii at different time points (prior infection, day 7, 35 and 56 after infection). In naive goats an increased expression of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, IL-10 and interferon (IFN)-gamma mRNA upon C. burnetii stimulation was detected. In addition, TLR2 expression was strongly up-regulated. In goats infected with C. burnetii, PBMCs re-stimulated in vitro with C. burnetii, expressed significantly more TNF-alpha mRNA and IFN-gamma mRNA compared to naive goats. In contrast, IL-10 mRNA production capacity was down-regulated during C. burnetii infection. Interestingly, at day 7 after inoculation a decreased IFN-gamma protein level was observed in stimulated leukocytes in whole blood from infected goats, whereas at other time-points increased production of IFN-gamma protein was seen. Our study shows that goats initiate a robust pro-inflammatory immune response against C. burnetii in vitro. Furthermore, PBMCs from C. burnetii infected goats show augmented pro-inflammatory cytokine responses compared to PBMCs from non-infected goats. However, despite this pro-inflammatory response, goats are not capable of clearing the C. burnetii infection.

Contains fulltext : 137713.pdf (publisher's version ) (Closed access)

Contains fulltext : 138374.pdf (publisher's version ) (Open Access), BACKGROUND: Q fever is caused by the intracellular bacterium Coxiella burnetii. Initial infection can present as acute Q fever, while a minority of infected individuals develops chronic Q fever endocarditis or vascular infection months to years after initial infection. Serology is an important diagnostic tool for both acute and chronic Q fever. However, since immunosuppressive drugs may hamper the humoral immune response, diagnosis of Q fever might be blurred when these drugs are used. CASE PRESENTATION: A 71-year-old Caucasian male was diagnosed with symptomatic acute Q fever (based on positive C. burnetii PCR followed by seroconversion) while using anti-tumor necrosis factor-alpha (anti-TNFalpha) drugs for rheumatoid arthritis (RA). He was treated for two weeks with moxifloxacin. After 24 months of follow-up, the diagnosis of probable chronic Q fever was established based on increasing anti-C. burnetii phase I IgG antibody titres in a immunocompromised patient combined with clinical suspicion of endocarditis. At the time of chronic Q fever diagnosis, he had been treated with anti B-cell therapy for 16 months. Antibiotic therapy consisting of 1.5 years doxycycline and hydroxychloroquine was started and successfully completed and no signs of relapse were seen after more than one year of follow-up. CONCLUSION: The use of anti-TNFalpha agents for RA in the acute phase of Q fever did not hamper the C. burnetii-specific serological response as measured by immunofluorescence assay. However, in the presented case, an intact humoral response did not prevent progression to probable chronic C. burnetii infection, most likely because essential cellular immune responses were suppressed during the acute phase of the infection. Despite the start of anti-B-cell therapy with rituximab after the acute Q fever episode, an increase in anti-C. burnetii phase I IgG antibodies was observed, supporting the notion that C. burnetii specific CD20-negative memory B-cells are responsible for

In humans, infection with Coxiella burnetii, the causative agent of Q fever, leads to acute or chronic infection, both associated with specific clinical symptoms. In contrast, no symptoms are observed in goats during C. burnetii infection, although infection of the placenta eventually leads to premature delivery, stillbirth and abortion. It is unknown whether these differences in clinical outcome are due to the early immune responses of the goats. Therefore, peripheral blood mononuclear cells (PBMCs) were isolated from pregnant goats. In total, 17 goats were included in the study. Six goats remained naive, while eleven goats were infected with C. burnetii. Toll-like receptor (TLR) and cytokine mRNA expression were measured after in vitro stimulation with heat-killed C. burnetii at different time points (prior infection, day 7, 35 and 56 after infection). In naive goats an increased expression of interleukin (IL)-1ß, tumor necrosis factor (TNF)-a, IL-10 and interferon (IFN)-¿ mRNA upon C. burnetii stimulation was detected. In addition, TLR2 expression was strongly up-regulated. In goats infected with C. burnetii, PBMCs re-stimulated in vitro with C. burnetii, expressed significantly more TNF-a mRNA and IFN-¿ mRNA compared to naive goats. In contrast, IL-10 mRNA production capacity was down-regulated during C. burnetii infection. Interestingly, at day 7 after inoculation a decreased IFN-¿ protein level was observed in stimulated leukocytes in whole blood from infected goats, whereas at other time-points increased production of IFN-¿ protein was seen. Our study shows that goats initiate a robust pro-inflammatory immune response against C. burnetii in vitro. Furthermore, PBMCs from C. burnetii infected goats show augmented pro-inflammatory cytokine responses compared to PBMCs from non-infected goats. However, despite this pro-inflammatory response, goats are not capable of clearing the C. burnetii infection.

Contains fulltext : 138832.pdf (publisher's version ) (Closed access), BACKGROUND: Following a large Q fever outbreak in the Netherlands, patients at risk for chronic Q fever received a whole-cell Q fever vaccine. Sensitized people were excluded based on pre-vaccination screening with skin test (ST) and serology. An investigational IFN-gamma-production assay was added. No previous experience existed for Q fever vaccination in this patient risk-group with predefined cardiac valvular anomalies or aortic aneurysm/prosthesis and many co-morbidities. We studied the adverse events (AE) and their association with patient characteristics and immunological parameters. METHODS: AE registration covered the week after skin test and 90 days following vaccination, with the use of diaries, interviews and spontaneous reports. Serious (S)AE were assessed immediately to ensure safety. We coded AE according to reported severity. Univariate and multivariate analysis addressed associations. RESULTS: Pre-vaccination screening led to exclusion of 182 patients with positive serology and 207 patients with positive skin test-reading. The skin test did not lead to any causally related SAE. Subsequent vaccination of 1370 patients did not reveal unexpected AE; however, 80% of vaccinees reported local AE (in 26% of these pronounced or extensive). The two causally related SAE (0.1%) both concerned a persistent subcutaneous injection site mass. AE were more frequent in women, younger patients, and those without immunosuppressive co-morbidity/medication. The occurrence of local AE after skin test was associated with pre-vaccination positive serology and high IFN-gamma production. This was also true for local AE following vaccination, with a strong association with local AE after skin test as well. The proportion of vaccinees with positive serology and positive IFN-gamma values 6 months after vaccination was higher in those with local AE after skin test or after vaccination (non-significant, probably due to small numbers). CONCLUSION: Q fever vaccination was safe but r

Contains fulltext : 137775.pdf (publisher's version ) (Open Access), Diagnosis of ongoing or past infection with Coxiella burnetii, the causative agent of Q fever, relies heavily on serology: the measurement of C. burnetii-specific antibodies, reflecting the host's humoral immune response. However, cell-mediated immune responses play an important, probably even more relevant, role in infections caused by the intracellular C. burnetii bacterium. Recent studies have investigated interferon-gamma (IFN-gamma) based assays, including a whole-blood IFN-gamma production assay and a Coxiella enzyme-linked immunospot (Coxiella ELISPOT), as potential diagnostic tools for Q fever diagnosis. Both are in-house developed assays using stimulating antigens of different origin. The main objective of this study was to compare the test performance of the IFN-gamma production assay and the Coxiella ELISPOT for detecting a cellular immune response to C. burnetii in Q fever patients, and to assess the correlation between both assays. To that end, both tests were performed in a well-defined patient group of chronic Q fever patients (n = 16) and a group of healthy seronegative individuals (n = 17). Among patients, both the Coxiella ELISPOT and the IFN-gamma production assay detected positive response in 14/16. Among controls, none were positive in the Coxiella ELISPOT, whereas the IFN-gamma production assay detected positive results in 1/17 and 3/17, when using Henzerling and Nine Mile as stimulating antigens, respectively. These results suggest the Coxiella ELISPOT has a somewhat higher specificity than the IFN-gamma production assay when Nine Mile is used as antigen stimulus. The assays showed moderate correlation: the Spearman correlation coefficient r ranged between 0.37-0.60, depending on the antigens used. Further investigation of the diagnostic potential for C. burnetii infection of both assays is warranted.

Contains fulltext : 125612.pdf (publisher's version ) (Closed access), OBJECTIVES: In the Netherlands, people at risk for chronic Q fever were vaccinated against Coxiella burnetii with the inactivated whole cell vaccine Q-vax(R). We aimed to measure the immune responses to C. burnetii six and twelve months after vaccination in this relevant population. METHODS: In 260 vaccinees, antibody responses were assessed by immunofluorescence assay (IFA), complement fixation test and ELISA. The cellular immune responses were assessed by measuring C. burnetii-specific interferon (IFN)-gamma production in blood. Serological results of 200 individuals with past Q fever were used for comparison. RESULTS: At six months, 46% of vaccinees showed low IFA antibody titres and 67% had a positive IFN-gamma assay; At twelve months, both were 60%. In contrast, individuals with a past Q fever were seropositive in 99.5% at six and twelve months, with relatively higher IFA titres. Interestingly, vaccinees with positive IFN-gamma assay pre-vaccination, showed a higher seroconversion rate than IFN-gamma negative vaccinees: 74% vs. 41% (p < 0.001). CONCLUSIONS: The immune response after Q-vax(R) vaccination is lower and restricted to a smaller proportion than found after past Q fever and than previously described after vaccination, suggesting decreased vaccine immunogenicity in this high-risk population. A positive IFN-gamma assay before vaccination in seronegative vaccinees likely points to pre-existing immunity resulting in boosting by vaccination.

Contains fulltext : 116678.pdf (publisher's version ) (Closed access), Background. Current practice for diagnosis of Q fever, caused by the intracellular pathogen Coxiella burnetii, relies mainly on serology and, in prevaccination assessment, on skin tests (STs), which both have drawbacks. In this study, C. burnetii-specific interferon gamma (IFN-gamma) production was used as a new diagnostic tool for previous Q fever, circumventing most of these drawbacks. Our aim was to compare this test to serology and ST. Methods. One thousand five hundred twenty-five individuals from an endemic area with a risk for chronic Q fever were enrolled. IFN-gamma production was measured after in vitro stimulation of whole blood with C. burnetii antigens. Various formats using different C. burnetii antigens were tested. Serology and ST were performed in all individuals. Results. In all assay formats, C. burnetii-specific IFN-gamma production was higher (P < .0001) in seropositive or ST-positive subjects than in seronegative and ST-negative subjects. Whole blood incubated for 24 hours with C. burnetii Nine Mile showed optimal performance. After excluding subjects with equivocal serology and/or borderline ST results, IFN-gamma production was 449 +/- 82 pg/mL in the positive individuals (n = 219) but only 21 +/- 3 pg/mL in negative subjects (n = 908). Using Bayesian analysis, sensitivity and specificity (87.0% and 90.2%, respectively) were similar to the combination of serology and ST (83.0% and 95.6%, respectively). Agreement with the combination of serology and ST was moderate (84% concordance; kappa = 0.542). Conclusions. Specific IFN-gamma detection is a novel diagnostic assay for previous C. burnetii infection and shows similar performance and practical advantages over serology and ST. Future studies to investigate the clinical value in practice are warranted.

Contains fulltext : 118232.pdf (publisher's version ) (Open Access), Understanding more about the host's immune response to different Cryptococcus spp. will provide additional insight into the pathogenesis of cryptocococcis. We hypothesized that the ability of C. gattii to cause disease in immunocompetent humans depends on a distinct innate cytokine response of the host to this emerging pathogen. In the current study we assessed the cytokine profile of human peripheral blood mononuclear cells (PBMCs) of healthy individuals, after in vitro stimulation with 40 different well-defined heat-killed isolates of C. gattii, C. neoformans and several hybrid strains. In addition, we investigated the involvement of TLR2, TLR4 and TLR9 in the pro-inflammatory cytokine response to C. gattii. Isolates of C. gattii induced higher concentrations of the pro-inflammatory cytokines IL-1beta, TNF-alpha and IL-6 and the Th17/22 cytokine IL-17 and IL-22 compared to C. neoformans var neoformans and C. neoformans var grubii. In addition, clinical C. gattii isolates induced higher amounts of cytokines than environmental isolates. This difference was not observed in C. neoformans var. grubii isolates. Furthermore, we demonstrated a likely contribution of TLR4 and TLR9, but no role for TLR2, in the host's cytokine response to C. gattii. In conclusion, clinical heat-killed C. gattii isolates induced a more pronounced inflammatory response compared to other Cryptococcus species and non-clinical C. gattii. This is dependent on TLR4 and TLR9 as cellular receptors.