Biomarkers for Early Diagnosis of Hemophagocytic Lymphohistiocytosis in Critically Ill Patients.

Many biomarkers have been proposed for the diagnosis of secondary hemophagocytic lymphohistiocytosis (HLH) in adults, but comparative studies are lacking. We analyzed ferritin, glycosylated ferritin, soluble CD25, CD163 and CD14, IL-6, IFN-γ, IL-18, IL-10, IL-1ß, IL-12p70, IL-17α, IP-10, and CXCL9 levels to differentiate HLH from sepsis in critically ill patients. Of 120 patients, HLH was confirmed for 14 patients. Among the biomarkers tested, ferritin, IL-18, and glycosylated ferritin were the most efficient parameters for early diagnosis of HLH. With a sensitivity set at 85%, ferritin, IL-18, and glycosylated ferritin were the biomarkers with the highest specificity: 84, 79, and 71% respectively. Combining IL-18 with the HScore provided a new score with an increased specificity compared to the HScore alone, 86% compared to 70% with a sensitivity set at 100%. A distinct cytokine pattern was highlighted in patients with malignancy-triggered HLH, with highly increased levels of INF-É£ and CXCL9, compared to HLH secondary to infection. This is the largest study available to date, comparing diagnostic biomarkers for HLH on a cohort of critically ill adult patients. Serum ferritin was the most discriminating parameter for early diagnosis of secondary HLH. IL18*HScore was identified as a highly potential score.

Detection of Herpesviridae in whole blood by multiplex PCR DNA-based microarray analysis after hematopoietic stem cell transplantation.

Viral infections are important causes of morbidity and mortality in patients after hematopoietic stem cell transplantation. The monitoring by PCR of Herpesviridae loads in blood samples has become a critical part of posttransplant follow-up, representing mounting costs for the laboratory. In this study, we assessed the clinical performance of the multiplex PCR DNA microarray Clart Entherpex kit for detection of cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6) as a screening test for virological follow-up. Two hundred fifty-five blood samples from 16 transplanted patients, prospectively tested by routine PCR assays, were analyzed by microarray. Routine PCR detected single or multiple viruses in 42% and 10% of the samples, respectively. Microarray detected single or multiple viruses in 34% and 18% of the samples, respectively. Microarray results correlated well with CMV and EBV detections by routine PCR (kappa tests = 0.79 and 0.78, respectively), whereas a weak correlation was observed with HHV-6 (0.43). HHV-7 was also detected in 48 samples by microarray. In conclusion, the microarray is a reliable screening assay for a posttransplant virological follow-up to detect CMV and EBV infections in blood. However, positive samples must be subsequently confirmed and viral loads must be quantified by PCR assays. Limitations were identified regarding HHV-6 detection. Although it is promising, is easy to use as a first-line test, and allows a reduction in the cost of analysis without undue delay in the reporting of the final quantitative result to the clinician, some characteristics of this microarray should be improved, particularly regarding quality control and the targeted virus panel, such that it could then be used as a routine test.

Comparative trends of brucellosis serological testing and confirmed brucellosis cases suggest inappropriate prescription habits.

BACKGROUND: Brucellosis is a zoonosis endemic to specific geographical regions. In first line laboratories, diagnosis is made by blood culture or Rose Bengal (RB) serology. METHODS: We compare brucellosis testing between 2012-2021 at two university hospitals in Brussels, Belgium with concomitant national confirmed cases and institutional cases. RESULTS: RB testing increased from 30 to 211 tests/year between 2012-2021. A total of fifty-two national brucellosis cases were notified during the study period, of which fifteen cases in Brussels. No trend was noted nationally or regionally. Epidemiological data indicated travel to endemic regions, confirmed by strain testing. Institutional cases all showed symptomatic presentations with positive travel histories. CONCLUSIONS: Serologic testing inappropriately increases yearly, while annual imported brucellosis cases remain rare, and have positive travel histories and are symptomatic. We therefore support current recommendations of limiting RB testing to symptomatic patients at risk of exposure, meaning predominantly positive recent travel history.

Streptobacillus moniliformis right hand abscess and monoarthritis following a rat bite.

Streptobacillus moniliformis is a zoonotic agent associated with rat bites. We present a patient with cellulitis, subcutaneous abscess, and septic mono-arthritis after a rat bite of the right hand. The patient had no systemic features of rat bite fever (RBF). S. moniliformis was cultured from purulent drainage of a thumb abscess. This case illustrates an unusual clinical presentation of streptobacillary infection after a rat bite.

Efficacy of systematic coronavirus screening by PCR and viral cultures in addition to triage in limiting the spread of SARS-CoV-2 within a hemodialysis unit.

BACKGROUND: Patients with end-stage-renal-disease (ESRD) undergoing hemodialysis (HD) represent a vulnerable population for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, due to their intrinsic fragility and increased exposure to the virus. Therefore, applying effective screening strategies and infection control measures is essential to control the spread of the epidemic within hemodialysis centers. OBJECTIVE: Description and evaluation of the efficacy of systematic screening by rt-PCR and viral cultures, in addition to triage to limit the spread of the epidemic. Evaluation of the performance of these tests using "post-hoc" SARS-CoV-2 serology as a surrogate marker of infection. METHODS: One hundred and forty-four patients undergoing hemodialysis in the Nephrology-Hemodialysis center of CHU Brugmann, Brussels, benefited from systematic virological screening using viral cultures in asymptomatic patients, or molecular tests (rt-PCR) for symptomatic ones, in addition to general prevention measures. Post-hoc serology was performed in all patients. RESULTS: Thirty-eight (26.3%) individuals were infected with SARS-CoV-2. Seventeen infected patients (44.7%) were asymptomatic and thus detected by viral culture. Our strategy allowed us to detect and isolate 97.4% of the infected patients, as proven by post-hoc serology. Only one patient, missed by clinical screening and sequential viral cultures, had a positive serology. CONCLUSION: The implementation of a control and prevention strategy based on a systematic clinical and virological screening showed its effectiveness in limiting (and shortening) the spread of the SARS-CoV-2 epidemic within our hemodialysis unit.

Severe Staphylococcus aureus infections in children: Case reports and management of positive Panton-Valentine leucocidin cases.

Background: Staphylococcus aureus is a well-known bacterium associated with carriage and responsible for different types of infections. The Panton-Valentine leucocidin (PVL) is a key virulence factor causing tissue necrosis. PVL can, however, be present in both benign and life-threatening infections. Case reports and management: We present three pediatric severe infections occurring over a period of only three weeks, in February 2021, and caused by genetically unrelated methicillin-sensitive Staphylococcus aureus producing PVL in a tertiary children's hospital in Belgium. The first one presented with necrotizing pneumonia, the second one with a neck abscess extended to the mediastinum, and the last one had sacral osteomyelitis complicated by endocarditis. The management of these infections is mostly based on expert opinions. The most appropriate treatment seems to be the combination of early surgical drainage of infected collections with an antibiotic regimen associating two antibiotics; beta-lactams and either clindamycin or linezolid. Human immunoglobulins also appear to be useful as adjunctive therapy. Conclusion: PVL-producing Staphylococcus aureus is associated with life-threatening infections in children. Prompt management is needed including surgery and appropriate antibiotic regimens.

Invasive non-typhoidal Salmonella infection complicated by metastatic infections: Report of three cases.

Non-typhoidal Salmonella (NTS) disease is usually a self-limiting infection presenting with digestive symptoms. However, disseminated presentation with involvement of secondary infectious sites is observed. We report diagnostic specificities and challenges related to the management of three patients with invasive NTS (iNTS) and secondary infectious locations. Among the seven patients (age range 46 - 83 years), four (two with extra-digestive infectious sites) had at least one immune debilitating condition. Two patients were incidentally discovered with iNTS and deceased after developing a septic shock despite antimicrobial treatment. Two individuals recovered under medical treatment without complications. Three other patients presented with secondary infectious sites. Case 1 suffered from urinary tract infection and dorsolumbar spondylodiscitis that responded well to antimicrobials and surgery. Abdominal prosthetic aortic aneurysm was diagnosed in case 2 and medical treatment only was applied. After four years of follow-up, he remains under antimicrobial treatment. Case 3 presented with conjoint thoracic aortic aneurysm and cutaneous abscesses managed with antimicrobials and surgery. Atherosclerosis and previous vascular intervention were the predisposing events for vascular involvement. iNTS is a serious disease carrying a high risk of mortality or secondary locations. Secondary locations can be managed by long duration antimicrobial therapy combined with surgery. Spine and aortitis are the most frequent secondary locations. Multi-drug resistant NTS represent an additional risk of mortality. Public health measures should be implemented to limit the spread of NTS to humans and the emergence of drug resistance.

Clinical features of Legionnaires' disease at three Belgian university hospitals, a retrospective study.

INTRODUCTION: Legionnaires' disease (LD) is a recognised cause of community-acquired pneumonia. However, Legionella is an overlooked pathogen in hospital-acquired pneumonia. The European Surveillance System 2008-2017 found 23% of the Belgian LD reported cases being healthcare-related, with a higher death-rate than in community-acquired patients. This study aims to describe patients admitted for community-acquired LD or affected by hospital-acquired LD and investigate discriminants associated with lethality. METHODS: Medical records were retrospectively reviewed at three Belgian University Hospitals, between 1 January 2016 up to 31 January 2019. Hospital-acquired LD was defined as symptom onset at 10 days or more after admission, according to the Centres for Disease Control and prevention. Community-acquired LD was defined as diagnosis at admission or within 10 days after admission. RESULTS: Fifty patients were included in the study, among them 26% were diagnosed with hospital-acquired LD. The case-fatality rate was 22%, with eight of the eleven deceased patients (73%) being in the hospital-acquired LD group. Medical history of asthma or chronic obstructive pulmonary disease and higher sequential organ failure assessment (SOFA) score at diagnosis were more frequently observed in the hospital-acquired LD group. Furthermore, significantly lower SOFA score at diagnosis of LD and higher rates of treatment with levofloxacin or moxifloxacin were observed in survivors. CONCLUSION: In the current cohort, LD death-rate was mainly driven by hospital-acquired LD patients. Hospital-acquired LD might especially affect patients with chronic respiratory disease. Respiratory fluoroquinolones treatment and lower SOFA score at diagnosis may be associated with favourable outcomes.

Clinical impact of the rapid molecular detection of RSV and influenza A and B viruses in the emergency department.

INTRODUCTION: Using respiratory virus rapid diagnostic tests in the emergency department could allow better and faster clinical management. Point-of-care PCR instruments now provide results in less than 30 minutes. The objective of this study was to assess the impact of the use of a rapid molecular diagnostic test, the cobas® Influenza A/B & RSV Assay, during the clinical management of emergency department patients. METHODS: Patients (adults and children) requiring admission or suffering from an underlying condition at risk of respiratory complications were prospectively recruited in the emergency department of four hospitals in the Brussels region. Physicians' intentions regarding admission, isolation, antibiotic, and antiviral use were collected before and after performing the rapid molecular test. Additionally, a comparison of the analytical performance of this test against antigen rapid tests and viral culture was performed as well as a time-to-result evaluation. RESULTS: Among the 293 patients recruited, 90 had a positive PCR, whereas 44 had a positive antigen test. PCR yielded a sensitivity of 100% for all targets. Antigen tests yielded sensitivities ranging from 66.7% for influenza B to 83.3% for respiratory syncytial virus (RSV). The use of PCR allowed a decrease in the overall need for isolation and treatment by limiting the isolation of negative patients and antibiotic use for positive patients. Meanwhile, antiviral treatments better targeted patients with a positive influenza PCR. CONCLUSION: The use of a rapid influenza and RSV molecular test improves the clinical management of patients admitted to the emergency department by providing a fast and reliable result. Their additional cost compared to antigen tests should be balanced with the benefit of their analytical performance, leading to efficient reductions in the need for isolation and antibiotic use.

Pandemic A/H1N1v influenza 2009 in hospitalized children: a multicenter Belgian survey.

BACKGROUND: During the 2009 influenza A/H1N1v pandemic, children were identified as a specific "at risk" group. We conducted a multicentric study to describe pattern of influenza A/H1N1v infection among hospitalized children in Brussels, Belgium. METHODS: From July 1, 2009, to January 31, 2010, we collected epidemiological and clinical data of all proven (positive H1N1v PCR) and probable (positive influenza A antigen or culture) pediatric cases of influenza A/H1N1v infections, hospitalized in four tertiary centers. RESULTS: During the epidemic period, an excess of 18% of pediatric outpatients and emergency department visits was registered. 215 children were hospitalized with proven/probable influenza A/H1N1v infection. Median age was 31 months. 47% had ≥ 1 comorbid conditions. Febrile respiratory illness was the most common presentation. 36% presented with initial gastrointestinal symptoms and 10% with neurological manifestations. 34% had pneumonia. Only 24% of the patients received oseltamivir but 57% received antibiotics. 10% of children were admitted to PICU, seven of whom with ARDS. Case fatality-rate was 5/215 (2%), concerning only children suffering from chronic neurological disorders. Children over 2 years of age showed a higher propensity to be admitted to PICU (16% vs 1%, p = 0.002) and a higher mortality rate (4% vs 0%, p = 0.06). Infants less than 3 months old showed a milder course of infection, with few respiratory and neurological complications. CONCLUSION: Although influenza A/H1N1v infections were generally self-limited, pediatric burden of disease was significant. Compared to other countries experiencing different health care systems, our Belgian cohort was younger and received less frequently antiviral therapy; disease course and mortality were however similar.

Opportunistic peritonitis in peritoneal dialysis: The example of Paracoccus yeei.

Paracoccus yeei, a Gram-negative coccobacillus, is an emergent opportunistic pathogen. It originates from soil and water. VITEK and MALDI-TOF are used for identification. There are few reports of peritoneal dialysis peritonitis. Its presentation is usually indolent. It can be successfully treated with several antibiotics: ß-lactams, aminoglycosides, without removing the catheter.

Covid-19 and blood groups: ABO antibody levels may also matter.

BACKGROUND: Susceptibility to Covid-19 has been found to be associated with the ABO blood group, with O type individuals being at a lower risk. However, the underlying mechanism has not been elucidated. Here, we aimed to test the hypothesis that Covid-19 patients might have lower levels of ABO antibodies than non-infected individuals as they could offer some degree of protection. METHODS: After showing that the viral spike protein harbors the ABO glycan epitopes when produced by cells expressing the relevant glycosyltransferases, like upper respiratory tract epithelial cells, we enrolled 290 patients with Covid-19 and 276 asymptomatic controls to compare their levels of natural ABO blood group antibodies. RESULTS: We found significantly lower IgM anti-A + anti-B agglutination scores in blood group O patients (76.93 vs 88.29, P-value = 0.034) and lower levels of anti-B (24.93 vs 30.40, P-value = 0.028) and anti-A antibodies (28.56 vs 36.50, P-value = 0.048) in blood group A and blood group B patients, respectively, compared to controls. CONCLUSION: In this study, we showed that ABO antibody levels are significantly lower in Covid-19 patients compared to controls. These findings could indicate that patients with low levels of ABO antibodies are at higher risk of being infected.

Alteration of humoral, cellular and cytokine immune response to inactivated influenza vaccine in patients with Sickle Cell Disease.

INTRODUCTION: Patients suffering from Sickle Cell Disease (SCD) are at increased risk for complications due to influenza virus. Annual influenza vaccination is strongly recommended but few clinical studies have assessed its immunogenicity in individuals with SCD. The aim of this study was to explore the biological efficacy of annual influenza vaccination in SCD patients by characterizing both their humoral and cell-mediated immunity against influenza antigen. We also aimed to investigate these immunological responses among SCD individuals according to their treatment (hydroxyurea (HU), chronic blood transfusions (CT), both HU and CT or none of them). METHODS: Seventy-two SCD patients (49 receiving HU, 9 on CT, 7 with both and 7 without treatment) and 30 healthy controls were included in the study. All subjects received the tetravalent influenza α-RIX-Tetra® vaccine from the 2016-2017 or 2017-2018 season. RESULTS: Protective anti-influenza HAI titers were obtained for the majority of SCD patients one month after vaccination but seroconversion rates in patient groups were strongly decreased compared to controls. Immune cell counts, particularly cellular memory including memory T and memory B cells, were greatly reduced in SCD individuals. Functional activation assays confirmed a poorer CD8+ T cell memory. We also document an imbalance of cytokines after influenza vaccination in SCD individuals with an INFγ/IL-10 ratio (Th1-type/Treg-type response) significantly lower in the SCD cohort. CONCLUSION: SCD patients undergoing CT showed altered immune regulation as compared to other treatment subgroups. Altogether, the cytokine imbalance, the high regulatory T cell levels and the low memory lymphocyte subset levels observed in the SCD cohort, namely for those on CT, suggest a poor ability of SCD patients to fight against influenza infection. Nevertheless, our serological data support current clinical practice for annual influenza vaccination, though immunogenicity to other vaccines involving immunological memory might be hampered in SCD patients and should be further investigated.

[The future of automation in bacteriology]. / Automatisation en bactériologie : quel avenir ? Un exemple concret dans le cadre d'une consolidation de laboratoires universitaires.

Bacteriology remained essentially manual for many years. After a partial automation for blood cultures, identifications and sensitivity testing, new technological developments including robotisation and digital pictures made it possible to open new ways. In the context of economic pression and need to increase the quality, automation offers multiple advantages concerning increase of productivity, standardization, traceability and decreasing of the delay to obtain the results. Moreover the use of digitalized pictures opens the way to tele-bacteriology, particularly useful when considering the merging of hospital laboratories because it makes it possible to geographically dissociate strict manipulation from the validation of the results and from the consultant activity of the microbiologist. The choice criteria of the equipment are detailed as well as the experience of the LHUB-ULB bacteriological laboratory which was automated at the time of merging of the Brussels public hospital laboratories and developed a conclusive experience of tele-bacteriology for the peripheral lab.

Contribution of a rapid influenza diagnostic test to manage hospitalized patients with suspected influenza.

AIM: To evaluate the performances of the Alere i influenza A&B test and to appraise its contribution to patient management. METHODS: In total, 267 samples were tested. Influenza A and B PCR was performed as the reference. For each positive result, the supervising physician was contacted to collect data regarding patient management. FINDINGS: The overall sensitivity and specificity of the Alere i were 91.4% and 97.6% for influenza A and 54.5% and 98.8% for influenza B, respectively. More specifically, when used in the emergency room (ER), the test helped avoid 10.7% of hospitalizations, 46.4% of antibiotic prescriptions and 42.9% of additional investigations for positive patients. The test was also helpful in instituting the prescription of oseltamivir and patient isolation. CONCLUSION: Alere i influenza A&B is a rapid, sensitive and specific diagnostic test for influenza A. Sensitivity for influenza B was poor. Its usefulness was more important when patients were still in the ER.

Performances of the H-Score for Diagnosis of Hemophagocytic Lymphohistiocytosis in Adult and Pediatric Patients.

OBJECTIVES: In this study, we compared the performances of adapted hemophagocytic lymphohistiocytosis (HLH)-2004 guidelines with those of the new diagnostic H-score to identify patients with HLH in a multicenter cohort consisting of adult and pediatric cases of suspected HLH. METHODS: The study sample consisted of 147 cases, including 20 adults and 16 children with HLH. Two sets of biological data were evaluated: at presentation and the maximal values reached during the episode. RESULTS: At presentation, for both children and adults, the H-score was more efficient than adapted HLH-2004 guidelines to identify HLH. The diagnostic sensitivity and specificity were respectively 100% and 80% for children and 90% and 79% for adults. However, for adults, performances became comparable between adapted HLH-2004 guidelines and H-score as patient clinical status worsened. The specificity decreased to 73% for the same sensitivity. CONCLUSIONS: The adapted HLH-2004 guidelines seem less powerful and H-score seems to be more appropriate for children, which may be due to less significantly marked biological features. For adults, H-score performances are better when determined at presentation. The cutoff value of the H-score should be adapted depending on the target population to obtain optimal specificity.