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Background Viruses and bacteria from the nasopharynx are capable of causing community-acquired pneumonia (CAP), which can be difficult to diagnose. We aimed to investigate whether shifts in the composition of these nasopharyngeal microbial communities can be used as diagnostic biomarkers for CAP in adults. Methods We collected nasopharyngeal swabs from adult CAP patients and controls without infection in a prospective multicenter case-control study design. We generated bacterial and viral profiles using 16S ribosomal RNA gene sequencing and multiplex polymerase chain reaction (PCR), respectively. Bacterial, viral, and clinical data were subsequently used as inputs for extremely randomized trees classification models aiming to distinguish subjects with CAP from healthy controls. Results We enrolled 117 cases and 48 control subjects. Cases displayed significant beta diversity differences in nasopharyngeal microbiota (P = . 016, R 2 =.01) compared to healthy controls. Our extremely randomized trees classification models accurately discriminated CAP caused by bacteria (area under the curve [AUC].83), viruses (AUC.95) or mixed origin (AUC.81) from healthy control subjects. We validated this approach using a dataset of nasopharyngeal samples from 140 influenza patients and 38 controls, which yielded highly accurate (AUC.93) separation between cases and controls. Conclusions Relative proportions of different bacteria and viruses in the nasopharynx can be leveraged to diagnose CAP and identify etiologic agent(s) in adult patients. Such data can inform the development of a microbiota-based diagnostic panel used to identify CAP patients and causative agents from nasopharyngeal samples, potentially improving diagnostic specificity, efficiency, and antimicrobial stewardship practices. [ABSTRACT FROM AUTHOR]

Background Deferral of men who have sex with men (MSM) from blood donation is highly debated. We therefore investigated their suitability to donate blood. Methods We compared the antibody prevalence of 10 sexually and transfusion-transmissible infections (TTIs) among 583 MSM and 583 age-matched repeat male blood donors. MSM were classified as low risk (lr) or medium-to-high risk (hr) based on self-reported sexual behavior and as qualified or unqualified using Dutch donor deferral criteria. Infection pressure (IP) was defined as the number of antibody-reactive infections, with class A infections (human immunodeficiency virus-1/2, hepatitis B virus, hepatitis C virus, human T-cell lymphotropic virus-1/2, syphilis) given double weight compared to class B infections (cytomegalovirus, herpes simplex virus-1/2, human herpesvirus 8, hepatitis E virus, parvovirus B19). Results Donors had a lower median IP than qualified lr-MSM and qualified hr-MSM (2 [interquartile range {IQR}, 1–2] vs 3 [IQR, 2–4]; P <.001). Low IP was found in 76% of donors, 39% of qualified lr-MSM, and 27% of qualified hr-MSM. The prevalence of class A infections did not differ between donors and qualified lr-MSM but was significantly higher in qualified hr-MSM and unqualified MSM. Recently acquired class A infections were detected in hr-MSM only. Compared to blood donors, human herpesviruses were more prevalent in all MSM groups (P <.001). Conclusions IP correlates with self-reported risk behavior among MSM. Although lr-MSM might form a low threat for blood safety with regard to class A infections, the high seroprevalence of human herpesviruses in lr-MSM warrants further investigation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests that hepatitis E virus (HEV) infection may occur in developed countries and that swine may act as a reservoir. We report a cluster of 2 confirmed cases and 1 presumptive case of hepatitis associated with HEV. The typed strain from 1 case was related to HEV strains found in North America and Europe, and it was also related to a cluster of swine HEV strains found in The Netherlands. Our findings indicate that locally acquired HEV infections in industrialized countries may be overlooked. Routine testing for HEV infection in patients with acute hepatitis in The Netherlands should be considered before a diagnosis of autoimmune hepatitis is reached and steroid therapy is initiated. [ABSTRACT FROM AUTHOR]