Nicole H. M. Renders

Chronic Q fever: review of the literature and a proposal of new diagnostic criteria.

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.

Follow-up of 686 patients with acute Q fever and detection of chronic infection

BACKGROUND Recent outbreaks in the Netherlands allowed for laboratory follow-up of a large series of patients with acute Q fever and for evaluation of test algorithms to detect chronic Q fever, a condition with considerable morbidity and mortality. METHODS For 686 patients with acute Q fever, IgG antibodies to Coxiella burnetii were determined using an immunofluorescence assay at 3, 6, and 12 months of follow-up. Polymerase chain reaction (PCR) was performed after 12 months and on earlier serum samples with an IgG phase I antibody titer ≥ 1:1024. RESULTS In 43% of patients, the IgG phase II antibody titers remained high (≥ 1:1024) at 3, 6, and 12 months of follow-up. Three months after acute Q fever, 14% of the patients had an IgG phase I titer ≥ 1:1024, which became negative later in 81%. IgG phase I antibody titers were rarely higher than phase II titers. Eleven cases of chronic Q fever were identified on the basis of serological profile, PCR results, and clinical presentation. Six of these patients were known to have clinical risk factors at the time of acute Q fever. In a comparison of various serological algorithms, IgG phase I titer ≥ 1:1024 at 6 months had the most favorable sensitivity and positive predictive value for the detection of chronic Q fever. CONCLUSIONS The wide variation of serological and PCR results during the follow-up of acute Q fever implies that the diagnosis of chronic Q fever, necessitating long-term antibiotic treatment, must be based primarily on clinical grounds. Different serological follow-up strategies are needed for patients with and without known risk factors for chronic Q fever.

Identification of risk factors for chronic Q fever, the Netherlands.

Previous cardiac valvular surgery, vascular prosthesis, aortic aneurysm, renal insufficiency, and older age increased risk.

Eradication of carriage with methicillin-resistant Staphylococcus aureus: effectiveness of a national guideline

BACKGROUND We evaluated the effectiveness of eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage in the Netherlands after the introduction of a guideline in 2006. The guideline distinguishes complicated (defined as the presence of MRSA infection, skin lesions, foreign-body material, mupirocin resistance and/or exclusive extranasal carriage) and uncomplicated carriage (not meeting criteria for complicated carriage). Mupirocin nasal ointment and chlorhexidine soap solution are recommended for uncomplicated carriers and the same treatment in combination with two oral antibiotics for complicated carriage. METHODS A prospective cohort study was performed in 18 Dutch centres from 1 October 2006 until 1 October 2008. RESULTS Six hundred and thirteen MRSA carriers underwent one or more decolonization treatments during the study period, mostly after hospital discharge. Decolonization was achieved in 367 (60%) patients with one eradication attempt and ultimately 493 (80%) patients were decolonized, with a median time until decolonization of 10 days (interquartile range 7-43 days). Three hundred and twenty-seven (62%) carriers were treated according to the guideline, which was associated with an absolute increase in treatment success of 20% [from 45% (91/203) to 65% (214/327)]. CONCLUSIONS Sixty percent of MRSA carriers were successfully decolonized after the first eradication attempt and 62% were treated according to the guideline, which was associated with an increased treatment success.

Chronic Q Fever in the Netherlands 5 Years after the Start of the Q Fever Epidemic: Results from the Dutch Chronic Q Fever Database

ABSTRACT Coxiella burnetii causes Q fever, a zoonosis, which has acute and chronic manifestations. From 2007 to 2010, the Netherlands experienced a large Q fever outbreak, which has offered a unique opportunity to analyze chronic Q fever cases. In an observational cohort study, baseline characteristics and clinical characteristics, as well as mortality, of patients with proven, probable, or possible chronic Q fever in the Netherlands, were analyzed. In total, 284 chronic Q fever patients were identified, of which 151 (53.7%) had proven, 64 (22.5%) probable, and 69 (24.3%) possible chronic Q fever. Among proven and probable chronic Q fever patients, vascular infection focus (56.7%) was more prevalent than endocarditis (34.9%). An acute Q fever episode was recalled by 27.0% of the patients. The all-cause mortality rate was 19.1%, while the chronic Q fever-related mortality rate was 13.0%, with mortality rates of 9.3% among endocarditis patients and 18% among patients with a vascular focus of infection. Increasing age (P = 0.004 and 0.010), proven chronic Q fever (P = 0.020 and 0.002), vascular chronic Q fever (P = 0.024 and 0.005), acute presentation with chronic Q fever (P = 0.002 and P < 0.001), and surgical treatment of chronic Q fever (P = 0.025 and P < 0.001) were significantly associated with all-cause mortality and chronic Q fever-related mortality, respectively.

Epidemic Q fever in humans in the Netherlands.

In 2005, Q fever was diagnosed on two dairy goat farms and 2 years later it emerged in the human population in the south of the Netherlands. From 2007 to 2010, more than 4,000 human cases were notified with an annual seasonal peak. The outbreaks in humans were mainly restricted to the south of the country in an area with intensive dairy goat farming. In the most affected areas, up to 15% of the population may have been infected. The epidemic resulted in a serious burden of disease, with a hospitalisation rate of 20% of notified cases and is expected to result in more cases of chronic Q fever among risk groups in the coming years. The most important risk factor for human Q fever is living close (<5 km) to an infected dairy goat farm. Occupational exposure plays a much smaller role. In 2009 several veterinary control measures were implemented including mandatory vaccination of dairy goats and dairy sheep, improved hygiene measures, and culling of pregnant animals on infected farms. The introduction of these drastic veterinary measures has probably ended the Q fever outbreak, for which the Netherlands was ill-prepared.

Screening for Coxiella burnetii seroprevalence in chronic Q fever high-risk groups reveals the magnitude of the Dutch Q fever outbreak

The Netherlands experienced an unprecedented outbreak of Q fever between 2007 and 2010. The Jeroen Bosch Hospital (JBH) in s-Hertogenbosch is located in the centre of the epidemic area. Based on Q fever screening programmes, seroprevalence of IgG phase II antibodies to Coxiella burnetii in the JBH catchment area was 10·7% [785 tested, 84 seropositive, 95% confidence interval (CI) 8·5-12·9]. Seroprevalence appeared not to be influenced by age, gender or area of residence. Extrapolating these data, an estimated 40 600 persons (95% CI 32 200-48 900) in the JBH catchment area have been infected by C. burnetii and are, therefore, potentially at risk for chronic Q fever. This figure by far exceeds the nationwide number of notified symptomatic acute Q fever patients and illustrates the magnitude of the Dutch Q fever outbreak. Clinicians in epidemic Q fever areas should be alert for chronic Q fever, even if no acute Q fever is reported.

Eradication of carriage with methicillin-resistant Staphylococcus aureus: determinants of treatment failure

BACKGROUND Using data from an observational study in which the effectiveness of a guideline for eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage was evaluated, we identified variables that were associated with treatment failure. METHODS A multivariate logistic regression model was performed with subgroup analyses for uncomplicated and complicated MRSA carriage (the latter including MRSA infection, skin lesions, foreign-body material, mupirocin resistance and/or exclusive extranasal carriage) and for those treated according to the guideline (i.e. mupirocin nasal ointment and chlorhexidine soap solution for uncomplicated carriage, in combination with two oral antibiotics for complicated carriage). RESULTS Six hundred and thirteen MRSA carriers were included, of whom 333 (54%) had complicated carriage; 327 of 530 patients (62%) with known complexity of carriage were treated according to the guideline with an absolute increase in treatment success of 20% (95% confidence interval 12%-28%). Among those with uncomplicated carriage, guideline adherence [adjusted odds ratio (OR(a)) 7.4 (1.7-31.7)], chronic pulmonary disease [OR(a) 44 (2.9-668)], throat carriage [OR(a) 2.9 (1.4-6.1)], perineal carriage [OR(a) 2.2 (1.1-4.4)] and carriage among household contacts [OR(a) 5.6 (1.2-26)] were associated with treatment failure. Among those with complicated carriage, guideline adherence was associated with treatment success [OR(a) 0.2 (0.1-0.3)], whereas throat carriage [OR(a) 4.4 (2.3-8.3)] and dependence in activities of daily living [OR(a) 3.6 (1.4-8.9)] were associated with failure. CONCLUSIONS Guideline adherence, especially among those with complicated MRSA carriage, was associated with treatment success. Adding patients with extranasal carriage or dependence in daily self-care activities to the definition of complicated carriage, and treating them likewise, may further increase treatment success.

Microbiological Challenges in the Diagnosis of Chronic Q Fever

ABSTRACT Diagnosis of chronic Q fever is difficult. PCR and culture lack sensitivity; hence, diagnosis relies mainly on serologic tests using an immunofluorescence assay (IFA). Optimal phase I IgG cutoff titers are debated but are estimated to be between 1:800 and 1:1,600. In patients with proven, probable, or possible chronic Q fever, we studied phase I IgG antibody titers at the time of positive blood PCR, at diagnosis, and at peak levels during chronic Q fever. We evaluated 200 patients, of whom 93 (46.5%) had proven, 51 (25.5%) had probable, and 56 (28.0%) had possible chronic Q fever. Sixty-five percent of proven cases had positive Coxiella burnetii PCR results for blood, which was associated with high phase I IgG. Median phase I IgG titers at diagnosis and peak titers in patients with proven chronic Q fever were significantly higher than those for patients with probable and possible chronic Q fever. The positive predictive values for proven chronic Q fever, compared to possible chronic Q fever, at titers 1:1,024, 1:2,048, 1:4,096, and ≥1:8,192 were 62.2%, 66.7%, 76.5%, and ≥86.2%, respectively. However, sensitivity dropped to <60% when cutoff titers of ≥1:8,192 were used. Although our study demonstrated a strong association between high phase I IgG titers and proven chronic Q fever, increasing the current diagnostic phase I IgG cutoff to >1:1,024 is not recommended due to increased false-negative findings (sensitivity < 60%) and the high morbidity and mortality of untreated chronic Q fever. Our study emphasizes that serologic results are not diagnostic on their own but should always be interpreted in combination with clinical parameters.

Methicillin-Resistant Staphylococcus aureus in a Beauty Salon, the Netherlands

An outbreak of community-associated USA300 methicillin-resistant Staphylococcus aureus occurred in a beautician and 2 of her customers. Eight other persons, who were either infected (n = 5) or colonized (n = 3), were linked to this outbreak, including a family member, a household contact, and partners of customers.