Evaluation of the SARS-CoV-2 positivity ratio and upper respiratory tract viral load among asymptomatic individuals screened before hospitalization or surgery in Flanders, Belgium

INTRODUCTION

The incidence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections in the Belgian community is mainly estimated based on test results of patients with coronavirus disease (COVID-19)-like symptoms. The aim of this study was to investigate the evolution of the SARS-CoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) positivity ratio and distribution of viral loads within a cohort of asymptomatic patients screened prior hospitalization or surgery, stratified by age category.

MATERIALS/METHODS

We retrospectively studied data on SARS-CoV-2 real-time RT-PCR detection in respiratory tract samples of asymptomatic patients screened pre-hospitalization or pre-surgery in nine Belgian hospitals located in Flanders over a 12-month period (1 April 2020-31 March 2021).

RESULTS

In total, 255925 SARS-CoV-2 RT-PCR test results and 2421 positive results for which a viral load was reported, were included in this study. An unweighted overall SARS-CoV-2 real-time RT-PCR positivity ratio of 1.27% was observed with strong spatiotemporal differences. SARS-CoV-2 circulated predominantly in 80+ year old individuals across all time periods except between the first and second COVID-19 wave and in 20-30 year old individuals before the second COVID-19 wave. In contrast to the first wave, a significantly higher positivity ratio was observed for the 20-40 age group in addition to the 80+ age group compared to the other age groups during the second wave. The median viral load follows a similar temporal evolution as the positivity rate with an increase ahead of the second wave and highest viral loads observed for 80+ year old individuals.

CONCLUSION

There was a high SARS-CoV-2 circulation among asymptomatic patients with a predominance and highest viral loads observed in the elderly. Moreover, ahead of the second COVID-19 wave an increase in median viral load was noted with the highest overall positivity ratio observed in 20-30 year old individuals, indicating they could have been the hidden drivers of this wave.

Multinational Observational Cohort Study of COVID-19-Associated Pulmonary Aspergillosis1

We performed an observational study to investigate intensive care unit incidence, risk factors, and outcomes of coronavirus disease-associated pulmonary aspergillosis (CAPA). We found 10%-15% CAPA incidence among 823 patients in 2 cohorts. Several factors were independently associated with CAPA in 1 cohort and mortality rates were 43%-52%.

Multicenter evaluation of the FilmArray Meningitis/Encephalitis assay in a routine setting

Introduction. The FilmArray Meningitis/Encephalitis (FA-ME) Panel (Biofire, Salt Lake City, Utah, US) enables fast and automated detection of 14 pathogens in cerebrospinal fluid (CSF).Gap statement. The performance of the FA-ME panel in a real routine setting has not yet been described and could lead to better patient management in cases of good performance.Aim. This multicenter study verified the FA-ME panel analytical performance in a routine hospital setting.Methodology. Between April 2016 and April 2018, 454 CSF samples were analysed with the FA-ME panel and compared with routine diagnostics. In cases of discrepancy or lack of a comparator result, a profound analysis based on patient records and other laboratory results was performed.Results. A first analysis of 65 frozen samples, suspicious for meningitis had a 89 % concordance with routine diagnostics. The limit of detection (LOD) was confirmed for all pathogens except for Streptococcus agalactiae and a strain of Haemophilus influenzae (Escherichia coli K1 and Cryptococcus gattii LOD experiments were not performed). The routine evaluation showed a positive result in 114 (25 %) clinical samples for at least one target. In three samples co-infections were found. After discrepancy analysis, overall sensitivity was 98 % (false negative FA-ME results for one HSV2, two HSV1 and two parechovirus). Four FA-ME results were considered false positive (two HHV6, one VZV and one E. coli K1), resulting in an overall specificity of >99 %. A clinical added value of the assay was seen in the diagnosis of eight cases of bacterial meningitis.Conclusion. Because of its rapidity and ease of use, the FA-ME panel has great potential in the diagnosis of central nervous infections. Implementation can improve clinical management, but costs and analytical limitations need to be addressed to convince clinicians and laboratories of its value.

Importance of anti-SARS-CoV-2 assay antigenic composition as revealed by the results of the Belgian external quality assessment (EQA) scheme

We report on sample IS/17575 since it generated highly divergent results in the Belgian SARS-CoV-2 serology external quality assessment scheme. Sample IS/17575 was serum originating from a 30 years old male patient. 124 diagnostic laboratories analysed this sample. A total of 168 results was returned (including 5 doubles). Overall, 38 were positive. All tests against S1 were positive except the Euroimmun IgG ELISA and the Ortho clinical Diagnostics VITROS IgG CLIA. All tests against S1/S2 (Liaison, Diasorin) resulted in a signal above cutoff. Assays against RBD, mostly generate a negative result. An exception are the Wantai SARS-CoV-2 ELISA's. All tests targeting N protein were negative. The survey shows, when >6 months post-infection, assays targeting at least S1, and preferably S1 combined with S2, are the most sensitive. This finding accentuates the necessity of external quality assessment schedules and importance of antigenic composition of serologic SARS-CoV-2 assays.

Acute SARS-CoV-2 alpha variant infection leading to placental insufficiency and fetal distress

The effect of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) Alpha variant (also known as B.1.1.7 lineage, 20I/501Y.V1, the UK variant or VOC 202012/01) infection on pregnancy is currently unknown.

We present a case of a 37‐year‐old woman admitted to our tertiary hospital at a gestational age of 29 weeks and 1 day because of oligohydramnios with reduced fetal movements for 10 days. About 20 days before admission, she tested positive for SARS‐CoV‐2 Alpha variant. The following day, due to abnormal cardiotocography, increased brain sparing, and absent end‐diastolic flow in the umbilical artery, an urgent cesarean section was performed. The neonate had an uneventful admission to the neonatal intensive care unit. All neonatal samples proved negative for SARS‐CoV‐2.

Pathological examination of the placenta revealed intervillous fibrin deposition, ischemic necrosis of villi and histiocytic intervillositis, corresponding with the SARS‐CoV‐2 placentitis triad. The placental tissue demonstrated a high viral load, possibly explaining the acute onset of placental insufficiently and subsequent fetal distress.

This case demonstrates the importance of seeking medical care when experiencing reduced fetal movement in SARS‐CoV‐2 infected patients since acute infection can induce significant placental and subsequent fetal pathology.

Spotlight influenza: Extending influenza surveillance to detect non-influenza respiratory viruses of public health relevance: analysis of surveillance data, Belgium, 2015 to 2019

BackgroundSeasonal influenza-like illness (ILI) affects millions of people yearly. Severe acute respiratory infections (SARI), mainly influenza, are a leading cause of hospitalisation and mortality. Increasing evidence indicates that non-influenza respiratory viruses (NIRV) also contribute to the burden of SARI. In Belgium, SARI surveillance by a network of sentinel hospitals has been ongoing since 2011.AimWe report the results of using in-house multiplex qPCR for the detection of a flexible panel of viruses in respiratory ILI and SARI samples and the estimated incidence rates of SARI associated with each virus.MethodsWe defined ILI as an illness with onset of fever and cough or dyspnoea. SARI was defined as an illness requiring hospitalisation with onset of fever and cough or dyspnoea within the previous 10 days. Samples were collected in four winter seasons and tested by multiplex qPCR for influenza virus and NIRV. Using catchment population estimates, we calculated incidence rates of SARI associated with each virus.ResultsOne third of the SARI cases were positive for NIRV, reaching 49.4% among children younger than 15 years. In children younger than 5 years, incidence rates of NIRV-associated SARI were twice that of influenza (103.5 vs 57.6/100,000 person-months); co-infections with several NIRV, respiratory syncytial viruses, human metapneumoviruses and picornaviruses contributed most (33.1, 13.6, 15.8 and 18.2/100,000 person-months, respectively).ConclusionEarly testing for NIRV could be beneficial to clinical management of SARI patients, especially in children younger than 5 years, for whom the burden of NIRV-associated disease exceeds that of influenza.

Dynamics of the cellular and humoral immune response after BNT162b2 mRNA Covid-19 vaccination in Covid-19 naive nursing home residents

Short-term humoral and cellular immune responses are diminished after BNT162b2 mRNA Covid-19 vaccination in Covid-19 naive nursing home residents, a population particularly vulnerable to the disease. We found both responses to decline after four weeks and remain lower than those of healthcare workers after twenty-four weeks, with an estimated half-life of the antibody response of 47 days. At four weeks, older age was significantly associated with a decreased humoral response, and diabetes mellitus and active malignancy with a decreased cellular response. Our results imply that Covid-19 naive nursing home residents are a target group for booster vaccination trials.

Risk factors and outcome of pulmonary aspergillosis in critically ill coronavirus disease 2019 patients-a multinational observational study by the European Confederation of Medical Mycology

Objectives

Coronavirus disease 2019 (COVID-19) -associated pulmonary aspergillosis (CAPA) has emerged as a complication in critically ill COVID-19 patients. The objectives of this multinational study were to determine the prevalence of CAPA in patients with COVID-19 in intensive care units (ICU) and to investigate risk factors for CAPA as well as outcome.

Methods

The European Confederation of Medical Mycology (ECMM) conducted a multinational study including 20 centres from nine countries to assess epidemiology, risk factors and outcome of CAPA. CAPA was defined according to the 2020 ECMM/ISHAM consensus definitions.

Results

A total of 592 patients were included in this study, including 11 (1.9%) patients with histologically proven CAPA, 80 (13.5%) with probable CAPA, 18 (3%) with possible CAPA and 483 (81.6%) without CAPA. CAPA was diagnosed a median of 8 days (range 0–31 days) after ICU admission predominantly in older patients (adjusted hazard ratio (aHR) 1.04 per year; 95% CI 1.02–1.06) with any form of invasive respiratory support (HR 3.4; 95% CI 1.84–6.25) and receiving tocilizumab (HR 2.45; 95% CI 1.41–4.25). Median prevalence of CAPA per centre was 10.7% (range 1.7%–26.8%). CAPA was associated with significantly lower 90-day ICU survival rate (29% in patients with CAPA versus 57% in patients without CAPA; Mantel–Byar p < 0.001) and remained an independent negative prognostic variable after adjusting for other predictors of survival (HR 2.14; 95% CI 1.59–2.87, p ≤ 0.001).

Conclusion

Prevalence of CAPA varied between centres. CAPA was significantly more prevalent among older patients, patients receiving invasive ventilation and patients receiving tocilizumab, and was an independent strong predictor of ICU mortality.

Hepatitis E virus-associated haemophagocytic lymphohistiocytosis

We report the first documented case of hepatitis E virus-associated haemophagocytic lymphohistiocytosis. This case emphasizes the fact that infectious agents other than those classically described should be taken into consideration as a potential trigger of virus-associated haemophagocytic syndrome. Prompt recognition is crucial to start early treatment of the underlying infection and possibly improve the outcome of this frequently fatal syndrome.

Comparison of 4 commercial enzyme immunoassays for serology testing of human parvovirus B19 infection

BACKGROUND

Parvovirus B19 is a pathogenic virus often diagnosed by serology, yet little is known about analytical performance of commercial enzyme immunoassays (EIAs).

OBJECTIVE

To investigate performance of 4 EIAs for parvovirus B19 IgM and IgG: Liaison, Euroimmun, Mikrogen and Virion/Serion.

STUDY DESIGN

To compare 4 EIAs to Biotrin's ELISA on 168 samples and determine consensus score for discordant samples using Mikrogen's confirmatory line assay.

RESULTS

Two thirds of results for IgM/IgG were identical for all 4 EIAs and Biotrin. Liaison shows the highest IgM sensitivity, but has low specificity. Euroimmun lacks IgM sensitivity. Mikrogen had a good overall performance, but had the lowest IgG specificity. Virion/Serion had variable performance with a low IgM specificity and the most borderline and cross-reactive results.

CONCLUSIONS

Liaison and Mikrogen have similar performance to Biotrin's ELISA. Euroimmun lacks sensitivity and Virion/Serion produced many borderline and cross-reactive results.

Pitfalls of rubella serology while on the brink of elimination: evaluation of national data, Belgium, 2017

BackgroundIn Belgium, rubella serology is frequently requested in women of childbearing age, despite high vaccination coverage and a near-absence of congenital rubella cases. Different test kits are available and should be standardised by an international standard preparation.AimTo analyse and compare rubella serology practices in Belgian laboratories.MethodsAs part of the mandatory External Quality Assessment programme for rubella serology in Belgium, the national public health institute, Sciensano, sent a voluntary questionnaire concerning anti-rubella IgM/IgG analyses in women aged 15 to 45 years in 2017 to 130 laboratories.ResultsThe questionnaire response rate was 83.8% (109/130). The majority of 169,494 IgG analyses were performed on Roche (55%), Abbott (17%) and Diasorin (13%) analysers. Not all laboratories used the proposed international cut-off of 10 IU/mL. Assumed median seroprevalence ranged from 76.3% with Liaison (Diasorin) to 96.3% with Modular (Roche). Despite very low rubella incidence in Belgium, 93 laboratories performed 85,957 IgM analyses, with 748 positive and 394 grey zone results. The National Reference Centre for Measles, Mumps and Rubella virus and the National Reference Centre for Congenital infections did not confirm any positive rubella cases in 2017.ConclusionThis retrospective analysis shows that rubella serology results may differ considerably according to the assay used. It is therefore important to use the same test when comparing results or performing follow-up testing. The number of anti-rubella IgM analyses was very high. Incorrect use of IgM for screening women of childbearing age can lead to unwarranted anxiety and overuse of confirmation tests.

Posaconazole for prevention of invasive pulmonary aspergillosis in critically ill influenza patients (POSA-FLU): a randomised, open-label, proof-of-concept trial

PURPOSE

Influenza-associated pulmonary aspergillosis (IAPA) is a frequent complication in critically ill influenza patients, associated with significant mortality. We investigated whether antifungal prophylaxis reduces the incidence of IAPA.

METHODS

We compared 7 days of intravenous posaconazole (POS) prophylaxis with no prophylaxis (standard-of-care only, SOC) in a randomised, open-label, proof-of-concept trial in patients admitted to an intensive care unit (ICU) with respiratory failure due to influenza (ClinicalTrials.gov, NCT03378479). Adult patients with PCR-confirmed influenza were block randomised (1:1) within 10 days of symptoms onset and 48 h of ICU admission. The primary endpoint was the incidence of IAPA during ICU stay in patients who did not have IAPA within 48 h of ICU admission (modified intention-to-treat (MITT) population).

RESULTS

Eighty-eight critically ill influenza patients were randomly allocated to POS or SOC. IAPA occurred in 21 cases (24%), the majority of which (71%, 15/21) were diagnosed within 48 h of ICU admission, excluding them from the MITT population. The incidence of IAPA was not significantly reduced in the POS arm (5.4%, 2/37) compared with SOC (11.1%, 4/36; between-group difference 5.7%; 95% CI - 10.8 to 21.7; p = 0.32). ICU mortality of early IAPA was high (53%), despite rapid antifungal treatment.

CONCLUSION

The higher than expected incidence of early IAPA precludes any definite conclusion on POS prophylaxis. High mortality of early IAPA, despite timely antifungal therapy, indicates that alternative management strategies are required. After 48 h, still 11% of patients developed IAPA. As these could benefit from prophylaxis, differentiated strategies are likely needed to manage IAPA in the ICU.

Lateral flow assays for diagnosing invasive pulmonary aspergillosis in adult hematology patients: A comparative multicenter study

Fast diagnosis of invasive pulmonary aspergillosis (IPA) is essential as early adequate therapy improves survival. However, current microbiological methods suffer from a low sensitivity or a long turnaround time, often as a result of batching. Recently, two lateral flow assays for diagnosing IPA have been CE (Conformité Européenne)-marked and commercialized. These assays can be used for fast single sample testing. However, clinical validation and comparative studies are lacking. We therefore sought to evaluate and compare these assays in adult hematology patients. We retrospectively tested 235 bronchoalveolar lavage fluid (BALf) samples of adult hematology patients from four centers using the AspLFD (OLM Diagnostics) and the sōna Aspergillus galactomannan LFA (IMMY). Both tests were read out independently by two researchers and by a digital reader. We included 11 patients with proven IPA, 64 with probable IPA, 43 with possible fungal disease, and 117 controls with no signs of IPA. In cases of proven IPA, the performance of both assays was similar. In cases of proven and probable IPA, we found an identical specificity for both assays, but a higher sensitivity (0.83 vs 0.69, P = .008) and a better negative predictive value (0.89 vs 0.82, P = .009) for the LFA. Digital readout improved the diagnostic performance of both tests. In conclusion, both assays showed a good performance for the diagnosis of IPA in BALf from adult hematology patients. Results were further improved by using a digital reader, especially for weakly positive results.

Monitoring of human coronaviruses in Belgian primary care and hospitals, 2015-20: a surveillance study

Background

Seasonal human coronaviruses (hCoVs) broadly circulate in humans. Their epidemiology and effect on the spread of emerging coronaviruses has been neglected thus far. We aimed to elucidate the epidemiology and burden of disease of seasonal hCoVs OC43, NL63, and 229E in patients in primary care and hospitals in Belgium between 2015 and 2020.

Methods

We retrospectively analysed data from the national influenza surveillance networks in Belgium during the winter seasons of 2015–20. Respiratory specimens were collected through the severe acute respiratory infection (SARI) and the influenza-like illness networks from patients with acute respiratory illness with onset within the previous 10 days, with measured or reported fever of 38°C or greater, cough, or dyspnoea; and for patients admitted to hospital for at least one night. Potential risk factors were recorded and patients who were admitted to hospital were followed up for the occurrence of complications or death for the length of their hospital stay. All samples were analysed by multiplex quantitative RT-PCRs for respiratory viruses, including seasonal hCoVs OC43, NL63, and 229E. We estimated the prevalence and incidence of seasonal hCoV infection, with or without co-infection with other respiratory viruses. We evaluated the association between co-infections and potential risk factors with complications or death in patients admitted to hospital with seasonal hCoV infections by age group. Samples received from week 8, 2020, were tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Findings

2573 primary care and 6494 hospital samples were included in the study. 161 (6·3%) of 2573 patients in primary care and 371 (5·7%) of 6494 patients admitted to hospital were infected with a seasonal hCoV. OC43 was the seasonal hCoV with the highest prevalence across age groups and highest incidence in children admitted to hospital who were younger than 5 years (incidence 9·0 [95% CI 7·2–11·2] per 100 000 person-months) and adults older than 65 years (2·6 [2·1–3·2] per 100 000 person-months). Among 262 patients admitted to hospital with seasonal hCoV infection and with complete information on potential risk factors, 66 (73·3%) of 90 patients who had complications or died also had at least one potential risk factor (p=0·0064). Complications in children younger than 5 years were associated with co-infection (24 [36·4%] of 66; p=0·017), and in teenagers and adults (≥15 years), more complications arose in patients with a single hCoV infection (49 [45·0%] of 109; p=0·0097). In early 2020, the Belgian SARI surveillance detected the first SARS-CoV-2-positive sample concomitantly with the first confirmed COVID-19 case with no travel history to China.

Interpretation

The main burden of severe seasonal hCoV infection lies with children younger than 5 years with co-infections and adults aged 65 years and older with pre-existing comorbidities. These age and patient groups should be targeted for enhanced observation when in medical care and in possible future vaccination strategies, and co-infections in children younger than 5 years should be considered during diagnosis and treatment. Our findings support the use of national influenza surveillance systems for seasonal hCoV monitoring and early detection, and monitoring of emerging coronaviruses such as SARS-CoV-2.

Funding

Belgian Federal Public Service Health, Food Chain Safety, and Environment; Belgian National Insurance Health Care (Institut national d'assurance maladie-invalidité/Rijksinstituut voor ziekte-en invaliditeitsverzekering); and Regional Health Authorities (Flanders Agentschap zorg en gezondheid, Brussels Commission communautaire commune, Wallonia Agence pour une vie de qualité).

Capturing respiratory syncytial virus season in Belgium using the influenza severe acute respiratory infection surveillance network, season 2018/19

Background

Respiratory syncytial virus (RSV) is a common cause of severe respiratory illness in young children (< 5 years old) and older adults (≥ 65 years old) leading the World Health Organization (WHO) to recommend the implementation of a dedicated surveillance in countries.

Aim

We tested the capacity of the severe acute respiratory infection (SARI) hospital network to contribute to RSV surveillance in Belgium.

Methods

During the 2018/19 influenza season, we started the SARI surveillance for influenza in Belgium in week 40, earlier than in the past, to follow RSV activity, which usually precedes influenza virus circulation. While the WHO SARI case definition for influenza normally used by the SARI hospital network was employed, flexibility over the fever criterion was allowed, so patients without fever but meeting the other case definition criteria could be included in the surveillance.

Results

Between weeks 40 2018 and 2 2019, we received 508 samples from SARI patients. We found an overall RSV detection rate of 62.4% (317/508), with rates varying depending on the age group: 77.6% in children aged < 5 years (253/326) and 34.4% in adults aged ≥ 65 years (44/128). Over 90% of the RSV-positive samples also positive for another tested respiratory virus (80/85) were from children aged < 5 years. Differences were also noted between age groups for symptoms, comorbidities and complications.

Conclusion

With only marginal modifications in the case definition and the period of surveillance, the Belgian SARI network would be able to substantially contribute to RSV surveillance and burden evaluation in children and older adults, the two groups of particular interest for WHO.

Successful Outcome of Disseminated Fusarium musae Fungemia with Skin Localization Treated with Liposomal Amphotericin B and Voriconazole in a Patient with Acute Myeloid Leukemia

Fusarium spp. may cause invasive disseminated infections in immunocompromised patients, associated with significant morbidity and mortality. We describe a case of disseminated fusariosis with fungemia and skin localization caused by Fusarium musae in a patient with acute myeloid leukemia successfully treated using liposomal amphotericin B and voriconazole.

Epidemiology of Pneumocystis jirovecii Pneumonia and (Non-)use of Prophylaxis

Objectives: Pneumocystis jirovecii pneumonia (PCP) is an AIDS-defining illness. In patients with HIV, the benefit of PCP prophylaxis is well-defined when the CD4 T-cell count decreases below 200 cells/μL. In other immunocompromised patients, the value of PCP prophylaxis is not always as well-established. This study aimed to describe the epidemiology of PCP in recent years and assess how many patients with PCP did or did not receive prophylaxis in the month preceding the infection. Material and Methods: A multicenter retrospective study was performed in 3 tertiary care hospital. A list of patients that underwent broncho-alveolar lavage sampling and Pneumocystis jirovecii (PJ) PCR testing was retrieved from the microbiology laboratories. An in-house PJ quantitative PCR (qPCR) was used in each center. A cycle threshold (Ct) value of ≤ 28.5-30 was considered a probable PCP. For patients with a positive PJ qPCR but above this threshold, a predefined case definition of possible PCP was defined as a qPCR Ct value ≤ 34-35 and both of the following criteria: 1. Clinical and radiological features compatible with PCP and 2. The patient died or received PCP therapy and survived. Patient files from those with a qPCR Ct value ≤ 35 were reviewed to determine whether the patient fulfilled the case definition and if PCP prophylaxis had been used in the weeks preceding the PCP. Disease-specific guidelines, as well as hospital-wide guidelines, were used to evaluate if prophylaxis could be considered indicated. Results: From 2012 to 2018, 482 BAL samples were tested. Two hundred and four had a qPCR Ct value ≤ 35 and were further evaluated: 90 fulfilled the definition of probable and 63 of possible PCP while the remaining 51 were considered colonized. Seventy-four percentages of the patients with PCP were HIV-negative. Only 11 (7%) of the 153 patients had received prophylaxis, despite that in 133 (87%) cases prophylaxis was indicated according to guidelines. Conclusion: In regions where HIV testing and treatment is available without restrictions, PCP is mainly diagnosed in non-HIV immunocompromised patients. More than four out of five patients with PCP had not received prophylaxis. Strategies to improve awareness of antimicrobial prophylaxis guidelines in immunocompromised patients are urgently needed.

Mycoplasma genitalium acquisition and macrolide resistance after initiation of HIV pre-exposure prophylaxis in men who have sex with men

OBJECTIVES

Recent evidence shows that patients using HIV pre-exposure prophylaxis (PrEP) have an increased rate of bacterial STIs, including syphilis, chlamydia and gonorrhoea. Our study aimed to describe the acquisition and the susceptibility for macrolides of Mycoplasma genitalium in men who have sex with men (MSM) on PrEP.

METHODS

We studied all MSM who started PrEP in the AZ Sint-Jan Hospital Bruges from 1 June 2017 to 31 March 2019 with at least one follow-up visit. Patients were screened for M. genitalium and other STIs with pooled rectal swabs, pharyngeal swabs and first-voided urine, and blood samples at baseline and quarterly intervals after initiating PrEP. TaqMan Array Card technology was used to detect M. genitalium and determine macrolide-resistance mediating mutations in region V of the 23S rRNA gene (A2058G, A2059G, A2058C and others). Patients with an STI were treated based on a national guideline.

RESULTS

131 MSM (median age 40 years, range 20-79) were included in the study. The median follow-up time was 12 months (IQR 6.1-17). Baseline prevalence of M. genitalium was 6.9% and incidence rate after PrEP initiation was 28.8 per 100 person-years (95% CI 21.7 to 37.2), without significant differences in proportions between the first four quarterly intervals. All but one acquisitions were asymptomatic. Younger age and positivity for M. genitalium at baseline were significantly associated with incident M. genitalium acquisition. The observed proportion of macrolide resistance increased not significantly from 44% at baseline to 57%-86% after PrEP initiation. None of the 27 macrolide-resistant M. genitalium acquisitions could be linked to azithromycin exposure in the three preceding months.

CONCLUSIONS

After initiation of PrEP, we found a stable incidence of almost exclusively asymptomatic M. genitalium. However, a non-significant trend of an increased percentage of macrolide-resistant strains was observed.

What is the risk of missing legionellosis relying on urinary antigen testing solely? A retrospective Belgian multicenter study

Currently, diagnosis of legionellosis relies mainly on urinary antigen testing (UAT) for Legionella pneumophila serogroup 1 (Lp1). However, this test has several limitations, particularly missing non-Lp1 infections. The purpose of this large multicenter study was to investigate the risk of missing legionellosis relying on UAT solely. Molecular results of Legionella detection as part of a first-line (syndromic) testing algorithm for severe respiratory tract infections were investigated retrospectively and compared with UAT results in 14 Belgian laboratories. Overall, 44.4% (20/45) UAT results appeared false negative and were reclassified as legionellosis based on PCR findings [Legionnaires' disease, 37.5% (15/40); Pontiac fever, 100% (5/5)]. A total of 39.4% (26/66) diagnosis probably would have been missed or delayed without a syndromic approach, as UAT or specific molecular testing for Legionella was not requested by the clinician. Furthermore, we confirmed the higher sensitivity of molecular Legionella detection in lower respiratory tract compared with upper respiratory tract specimens (p = 0.010).

Serial Detection of Circulating Mucorales DNA in Invasive Mucormycosis: A Retrospective Multicenter Evaluation

Invasive mucormycosis is a fungal infection with high mortality. Early diagnosis and initiation of appropriate treatment is essential to improve survival. However, current diagnostic tools suffer from low sensitivity, leading to delayed or missed diagnoses. Recently, several PCR assays for the detection of Mucorales DNA have been developed. We retrospectively assessed the diagnostic and kinetic properties of a commercial Mucorales PCR assay (MucorGenius^®, PathoNostics) on serial blood samples from patients with culture-positive invasive mucormycosis and found an overall sensitivity of 75%. Importantly, a positive test preceded a positive culture result by up to 81 days (median eight days, inter-quartile range 1.75–16.25). After initiation of appropriate therapy, the average levels of circulating DNA decreased after one week and stabilized after two weeks. In conclusion, detection of circulating Mucorales DNA appears to be a good, fast diagnostic test that often precedes the final diagnosis by several days to weeks. This test could be especially useful in cases in which sampling for culture or histopathology is not feasible.