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Contains fulltext : 171709.pdf (publisher's version ) (Open Access)

Contains fulltext : 171709.pdf (publisher's version ) (Open Access)

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 : 137608.pdf (publisher's version ) (Closed access), Infection with Coxiella burnetii may lead to life-threatening chronic Q fever endocarditis or vascular infections, which are often difficult to diagnose. The present study aims to investigate whether measurement of in-vitro interferon-gamma (IFN-gamma) production, a key cytokine in the immune response against C. burnetii, differentiates chronic from a past cleared infection, and whether measurement of other cytokines would improve the discriminative power. First, C. burnetii-specific IFN-gamma production was measured in whole blood of 28 definite chronic Q fever patients and compared with 135 individuals with past Q fever (seropositive controls) and 908 seronegative controls. IFN-gamma production was significantly higher in chronic Q fever patients than in controls, but with overlapping values between patients and seropositives. Secondly, the production of a series of other cytokines was measured in a subset of patients and controls, which showed that interleukin (IL)-2 production was significantly lower in patients than in seropositive controls. Subsequently, measuring IL-2 in all patients and all controls with substantial IFN-gamma production showed that an IFN-gamma/IL-2 ratio >11 had a sensitivity and specificity of 79% and 96%, respectively, to diagnose chronic Q fever. This indicates that a high IFN-gamma/IL-2 ratio is highly suggestive for chronic Q fever. In an additional group of 25 individuals with persistent high anti-Coxiella phase I IgG titres without definite chronic infection, all but six showed an IFN-gamma/IL-2 ratio <11. In conclusion, these findings hold promise for the often difficult diagnostic work-up of Q fever and the IFN-gamma/IL-2 ratio may be used as an additional diagnostic marker.

Contains fulltext : 137608.pdf (publisher's version ) (Closed access), Infection with Coxiella burnetii may lead to life-threatening chronic Q fever endocarditis or vascular infections, which are often difficult to diagnose. The present study aims to investigate whether measurement of in-vitro interferon-gamma (IFN-gamma) production, a key cytokine in the immune response against C. burnetii, differentiates chronic from a past cleared infection, and whether measurement of other cytokines would improve the discriminative power. First, C. burnetii-specific IFN-gamma production was measured in whole blood of 28 definite chronic Q fever patients and compared with 135 individuals with past Q fever (seropositive controls) and 908 seronegative controls. IFN-gamma production was significantly higher in chronic Q fever patients than in controls, but with overlapping values between patients and seropositives. Secondly, the production of a series of other cytokines was measured in a subset of patients and controls, which showed that interleukin (IL)-2 production was significantly lower in patients than in seropositive controls. Subsequently, measuring IL-2 in all patients and all controls with substantial IFN-gamma production showed that an IFN-gamma/IL-2 ratio >11 had a sensitivity and specificity of 79% and 96%, respectively, to diagnose chronic Q fever. This indicates that a high IFN-gamma/IL-2 ratio is highly suggestive for chronic Q fever. In an additional group of 25 individuals with persistent high anti-Coxiella phase I IgG titres without definite chronic infection, all but six showed an IFN-gamma/IL-2 ratio <11. In conclusion, these findings hold promise for the often difficult diagnostic work-up of Q fever and the IFN-gamma/IL-2 ratio may be used as an additional diagnostic marker.

Contains fulltext : 137608.pdf (publisher's version ) (Closed access), Infection with Coxiella burnetii may lead to life-threatening chronic Q fever endocarditis or vascular infections, which are often difficult to diagnose. The present study aims to investigate whether measurement of in-vitro interferon-gamma (IFN-gamma) production, a key cytokine in the immune response against C. burnetii, differentiates chronic from a past cleared infection, and whether measurement of other cytokines would improve the discriminative power. First, C. burnetii-specific IFN-gamma production was measured in whole blood of 28 definite chronic Q fever patients and compared with 135 individuals with past Q fever (seropositive controls) and 908 seronegative controls. IFN-gamma production was significantly higher in chronic Q fever patients than in controls, but with overlapping values between patients and seropositives. Secondly, the production of a series of other cytokines was measured in a subset of patients and controls, which showed that interleukin (IL)-2 production was significantly lower in patients than in seropositive controls. Subsequently, measuring IL-2 in all patients and all controls with substantial IFN-gamma production showed that an IFN-gamma/IL-2 ratio >11 had a sensitivity and specificity of 79% and 96%, respectively, to diagnose chronic Q fever. This indicates that a high IFN-gamma/IL-2 ratio is highly suggestive for chronic Q fever. In an additional group of 25 individuals with persistent high anti-Coxiella phase I IgG titres without definite chronic infection, all but six showed an IFN-gamma/IL-2 ratio <11. In conclusion, these findings hold promise for the often difficult diagnostic work-up of Q fever and the IFN-gamma/IL-2 ratio may be used as an additional diagnostic marker.

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 : 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.

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Contains fulltext : 109522.pdf (publisher's version ) (Open Access), From 2007 to 2009, the Netherlands faced large seasonal outbreaks of Q fever, in which infected dairy goat farms were identified as the primary sources. Veterinary measures including vaccination of goats and sheep and culling of pregnant animals on infected farms seem to have brought the Q fever problem under control. However, the epidemic is expected to result in more cases of chronic Q fever among risk groups in the coming years. In the most affected area, in the south of the country, more than 12% of the population now have antibodies against Coxiella burnetii. Questions remain about the follow-up of acute Q fever patients, screening of groups at risk for chronic Q fever, screening of donors of blood and tissue, and human vaccination. There is a considerable ongoing research effort as well as enhanced veterinary and human surveillance.

01 maart 2012, Item does not contain fulltext, A review was performed to determine clinical aspects and diagnostic tools for chronic Q fever. We present a Dutch guideline based on literature and clinical experience with chronic Q fever patients in The Netherlands so far. In this guideline diagnosis is categorized as proven, possible or probable chronic infection based on serology, PCR, clinical symptoms, risk factors and diagnostic imaging.

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Contains fulltext : 109522.pdf (publisher's version ) (Open Access), From 2007 to 2009, the Netherlands faced large seasonal outbreaks of Q fever, in which infected dairy goat farms were identified as the primary sources. Veterinary measures including vaccination of goats and sheep and culling of pregnant animals on infected farms seem to have brought the Q fever problem under control. However, the epidemic is expected to result in more cases of chronic Q fever among risk groups in the coming years. In the most affected area, in the south of the country, more than 12% of the population now have antibodies against Coxiella burnetii. Questions remain about the follow-up of acute Q fever patients, screening of groups at risk for chronic Q fever, screening of donors of blood and tissue, and human vaccination. There is a considerable ongoing research effort as well as enhanced veterinary and human surveillance.

01 maart 2012, Item does not contain fulltext, A review was performed to determine clinical aspects and diagnostic tools for chronic Q fever. We present a Dutch guideline based on literature and clinical experience with chronic Q fever patients in The Netherlands so far. In this guideline diagnosis is categorized as proven, possible or probable chronic infection based on serology, PCR, clinical symptoms, risk factors and diagnostic imaging.

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Contains fulltext : 109522.pdf (publisher's version ) (Open Access), From 2007 to 2009, the Netherlands faced large seasonal outbreaks of Q fever, in which infected dairy goat farms were identified as the primary sources. Veterinary measures including vaccination of goats and sheep and culling of pregnant animals on infected farms seem to have brought the Q fever problem under control. However, the epidemic is expected to result in more cases of chronic Q fever among risk groups in the coming years. In the most affected area, in the south of the country, more than 12% of the population now have antibodies against Coxiella burnetii. Questions remain about the follow-up of acute Q fever patients, screening of groups at risk for chronic Q fever, screening of donors of blood and tissue, and human vaccination. There is a considerable ongoing research effort as well as enhanced veterinary and human surveillance.

01 maart 2012, Item does not contain fulltext, A review was performed to determine clinical aspects and diagnostic tools for chronic Q fever. We present a Dutch guideline based on literature and clinical experience with chronic Q fever patients in The Netherlands so far. In this guideline diagnosis is categorized as proven, possible or probable chronic infection based on serology, PCR, clinical symptoms, risk factors and diagnostic imaging.

1 april 2011, Item does not contain fulltext, OBJECTIVES: We evaluated the changes in antibiotic resistance from 1998 to 2009 of Klebsiella pneumoniae isolated from the intensive care units (ICUs) and urology services of 14 Dutch hospitals and the consequences for empirical therapy. METHODS: Quantitative antibiotic susceptibility testing of K. pneumoniae was performed in a central laboratory using a microbroth dilution method. Breakpoints were as defined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The prevalence of extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing isolates was determined. RESULTS: A significant increase in resistance among ICU isolates was observed for ceftazidime (4.2%-10.8%), ciprofloxacin (5.8%-18.5%) and trimethoprim/sulfamethoxazole (11.9%-23.1%), and for cefuroxime (2.8%-7.9%) and trimethoprim/sulfamethoxazole (13.5%-27.8%) among urology isolates. Among ICU isolates the prevalence of ESBLs increased significantly from 2% to 8%. Carbapenemase production was not demonstrated. Among ICU isolates the prevalence of multidrug resistance increased and has been >/=12% since 2004. Among urology isolates multidrug resistance was highest in 2009 at 7.4%. Overall, resistance was significantly higher among ICU isolates. CONCLUSIONS: We observed an increase in resistance among ICU and urology isolates and an increased prevalence of ESBLs among ICU isolates. Carbapenemase production was not demonstrated. A regular update of empirical treatment protocols based on actual surveillance data is justified.

01 april 2011, Item does not contain fulltext, OBJECTIVES: We evaluated the changes in antibiotic resistance from 1998 to 2009 of Klebsiella pneumoniae isolated from the intensive care units (ICUs) and urology services of 14 Dutch hospitals and the consequences for empirical therapy. METHODS: Quantitative antibiotic susceptibility testing of K. pneumoniae was performed in a central laboratory using a microbroth dilution method. Breakpoints were as defined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The prevalence of extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing isolates was determined. RESULTS: A significant increase in resistance among ICU isolates was observed for ceftazidime (4.2%-10.8%), ciprofloxacin (5.8%-18.5%) and trimethoprim/sulfamethoxazole (11.9%-23.1%), and for cefuroxime (2.8%-7.9%) and trimethoprim/sulfamethoxazole (13.5%-27.8%) among urology isolates. Among ICU isolates the prevalence of ESBLs increased significantly from 2% to 8%. Carbapenemase production was not demonstrated. Among ICU isolates the prevalence of multidrug resistance increased and has been >/=12% since 2004. Among urology isolates multidrug resistance was highest in 2009 at 7.4%. Overall, resistance was significantly higher among ICU isolates. CONCLUSIONS: We observed an increase in resistance among ICU and urology isolates and an increased prevalence of ESBLs among ICU isolates. Carbapenemase production was not demonstrated. A regular update of empirical treatment protocols based on actual surveillance data is justified.

01 april 2011, Item does not contain fulltext, OBJECTIVES: We evaluated the changes in antibiotic resistance from 1998 to 2009 of Klebsiella pneumoniae isolated from the intensive care units (ICUs) and urology services of 14 Dutch hospitals and the consequences for empirical therapy. METHODS: Quantitative antibiotic susceptibility testing of K. pneumoniae was performed in a central laboratory using a microbroth dilution method. Breakpoints were as defined by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The prevalence of extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing isolates was determined. RESULTS: A significant increase in resistance among ICU isolates was observed for ceftazidime (4.2%-10.8%), ciprofloxacin (5.8%-18.5%) and trimethoprim/sulfamethoxazole (11.9%-23.1%), and for cefuroxime (2.8%-7.9%) and trimethoprim/sulfamethoxazole (13.5%-27.8%) among urology isolates. Among ICU isolates the prevalence of ESBLs increased significantly from 2% to 8%. Carbapenemase production was not demonstrated. Among ICU isolates the prevalence of multidrug resistance increased and has been >/=12% since 2004. Among urology isolates multidrug resistance was highest in 2009 at 7.4%. Overall, resistance was significantly higher among ICU isolates. CONCLUSIONS: We observed an increase in resistance among ICU and urology isolates and an increased prevalence of ESBLs among ICU isolates. Carbapenemase production was not demonstrated. A regular update of empirical treatment protocols based on actual surveillance data is justified.