ABSTRACT
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.
Subject(s)
Antibodies, Bacterial/blood , Clinical Laboratory Techniques/methods , Coxiella burnetii/immunology , Immunoglobulin G/blood , Q Fever/diagnosis , Aged , Aged, 80 and over , Chronic Disease , Female , Fluorescent Antibody Technique, Indirect/methods , Follow-Up Studies , Humans , Male , Middle Aged , Netherlands , Polymerase Chain Reaction/methods , Q Fever/immunology , Q Fever/microbiology , Q Fever/pathology , Sensitivity and SpecificityABSTRACT
OBJECTIVE: To study the effect of subglottic secretions drainage on the incidence of ventilator-associated pneumonia (VAP) in patients receiving mechanical ventilation. DESIGN: A randomized clinical trial. SETTING: A 12-bed general ICU. PATIENTS: One hundred fifty patients with an expected duration of mechanical ventilation > 72 h were enrolled in the study. INTERVENTION: Patients were randomly assigned to receive either an endotracheal tube for intermittent subglottic secretions drainage or a standard endotracheal tube. OUTCOME MEASUREMENTS: Incidence of VAP, duration of mechanical ventilation, length of ICU stay, length of hospital stay, and mortality. RESULTS: Seventy-five patients were randomized to subglottic secretion drainage, and 75 patients were randomized to the control group. The two groups were similar at the time of randomization with respect to demographic characteristics and severity of illness. VAP was seen in 3 patients (4%) receiving suction secretion drainage and in 12 patients (16%) in the control group (relative risk, 0.22; 95% confidence interval, 0.06 to 0.81; p = 0.014). The other outcome measures were not significantly different between the two groups. CONCLUSION: Intermittent subglottic secretion drainage reduces the incidence of VAP in patients receiving mechanical ventilation.
