Bacterial meningitis in hematopoietic stem cell transplant recipients: a population-based prospective study

Listeria monocytogenes Infections in Hematopoietic Cell Transplantation Recipients: Clinical Manifestations and Risk Factors. A Multinational Retrospective Case-Control Study from the Infectious Diseases Working Party of the European Society for Blood and Marrow Transplantation

Listeriosis is rare after hematopoietic stem cell transplantation (HCT). Little is known about listeriosis in this population. In this retrospective international case-control study, we evaluated 41 listeriosis episodes occurring between 2000 and 2021 in HCT recipients (111 transplant centers in 30 countries) and assessed risk factors for listeriosis by comparisons with matched controls. The 41 listeriosis episodes (all due to Listeria monocytogenes [LM]) occurred in 30 allogeneic (allo)-HCT recipients and 11 autologous (auto)-HCT recipients at a median of 6.2 months (interquartile range [IQR], 1.6 to 19.3 months) post-HCT. The estimated incidence was 49.8/100,000 allo-HCT recipients and 13.7/100,000 auto-HCT recipients. The most common manifestations in our cohort were fever (n = 39; 95%), headache (n = 9; 22%), diarrhea, and impaired consciousness (n = 8 each; 20%). Four patients (10%) presented with septic shock, and 19 of 38 (50%) were severely lymphocytopenic. Thirty-seven patients (90%) had LM bacteremia. Eleven patients (27%) had neurolisteriosis, of whom 4 presented with nonspecific signs and 5 had normal brain imaging findings. Cerebrospinal fluid analysis revealed high protein and pleocytosis (mainly neutrophilic). Three-month mortality was 17% overall (n = 7), including 27% (n = 3 of 11) in patients with neurolisteriosis and 13% (n = 4 of 30) in those without neurolisteriosis. In the multivariate analysis comparing cases with 74 controls, non-first HCT (odds ratio [OR], 5.84; 95% confidence interval [CI], 1.10 to 30.82; P = .038); and lymphocytopenia <500 cells/mm3 (OR, 7.54; 95% CI, 1.50 to 37.83; P = .014) were significantly associated with listeriosis. There were no statistically significant differences in background characteristics, immunosuppression, and cotrimoxazole prophylaxis between cases and controls. HCT recipients are at increased risk for listeriosis compared to the general population. Listeriosis cause severe disease with septic shock and mortality. Neurolisteriosis can present with nonspecific signs and normal imaging. Lymphocytopenia and non-first HCT are associated with an increased risk of listeriosis, and cotrimoxazole was not protective.

Facilitators and Barriers to Successful Revaccination after Hematopoietic Stem Cell Transplantation among Adult Survivors: A Scoping Review

Post-transplantation revaccination uptake of childhood vaccines in adult hematopoietic stem cell transplantation (HSCT) survivors is suboptimal, increasing the risk of infectious morbidity and mortality within this population. We systematically reviewed the literature for factors related to revaccination uptake, as well as the barriers and facilitators that affect successful revaccination. We conducted a scoping review searching PubMed, CINAHL, Embase, and Web of Science in March 2023. Two independent reviewers performed study selection using the complete dual review process. Data were extracted using a standard form. Factors were characterized as demographic, clinical, or social determinants of health that affected revaccination uptake. Barriers and facilitators were categorized using the constructs from the World Health Organization Behavioural and Social Drivers Framework. Our searches yielded 914 sources, from which 15 publications were selected (5 original research and 10 quality improvement initiatives). More than one-half of the reports listed factors associated with poorer uptake, predominately clinical factors, followed by social determinants of health, then demographic factors. Nearly all the reports described barriers to successful revaccination uptake, with most of these falling into the "practical issues" construct. Most of the reports described facilitators, nearly all related to health care system improvements associated with improved revaccination uptake. Although this review provides a good starting point for understanding impediments to successful revaccination after HSCT, this review reveals that we lack sufficient evidence to drive targeted interventions to improve uptake. More research is needed, focusing on survivors' voices to inform our knowledge of barriers and facilitators to complete revaccination after HSCT, exploring behavioral and social drivers within this population, and examining the care delivery models that may complicate vaccine delivery in this population.

[Invasive meningococcal disease: increased risk and vaccination prevention for immunocompromised patients]

BACKGROUND

The development of evidence-based guidelines for the prevention of infectious diseases through vaccination requires an understanding of populations that most likely may obtain an infection, severe illness or disease. Targeted vaccination recommendations are made possible by identifying risk groups, as is the case with meningococcal infections. Despite falling case numbers, meningococcal sepsis and meningococcal meningitis remain a major health problem.

METHOD

A systematic literature search was carried out on the research platform Ovid.

RESULTS

Vulnerable groups of people whose immune system is limited by primary and secondary immunodeficiency, such as asplenia, renal failure, human immunodeficiency virus (HIV) infection, diabetes, complement deficiency, organ and stem cell transplants, or immunomodulatory therapy (e.g., in rheumatic, hematological or oncological diseases), are exposed to an increased risk of infection and more severe courses of disease. Despite adequate medical care, the mortality rate is high and patients that survived the infection are often suffering from severe long-term sequelae. In such cases, the vaccination recommendations of the Standing Committee on Vaccination (STIKO) for indication vaccinations and the application instructions for vaccination in the case of immune deficiency should be consistently implemented in Germany.

CONCLUSIONS

Increased responsibility for comprehensive protection must be assumed for persons with underlying diseases. Reducing invasive meningococcal infections can be achieved through widespread education of patients and contacts, as well as practicing physicians on available vaccinations.

Clinical application value of metagenomic second-generation sequencing technology in hematologic diseases with and without transplantation

Introduction

Hematological patients are at risk of infections. It is unknown whether the pathogenic microbial spectrum differs between HSCT and non-HSCT patients, and whether metagenomic next-generation sequencing (mNGS) of peripheral blood can be used as a substitute test specimen such as alveolar lavage.

Methods

A retrospective study was conducted to evaluate the clinical application value of mNGS in hematological patients with and without HSCT.

Results

Viruses were prevalent pathogens in both non-HSCT (44%) and HSCT (45%) patients, chiefly human cytomegalovirus and Epstein-Barr virus. In non-HSCT patients, Gram-negative bacilli accounted for 33% (predominantly Klebsiella pneumonia), and Gram-positive cocci accounted for 7% (predominantly Enterococcus faecium) of pathogens. However, in HSCT patients, Gram-negative bacilli accounted for 13% (predominantly Stenotrophomonas maltophilia), and Gram-positive cocci accounted for 24% (predominantly Streptococcus pneumonia) of pathogens. Mucor was the most common fungu s in two groups. The positive rate of pathogens by mNGS was 85.82%, higher than conventional detection (20.47%, P < 0.05). Mixed infection accounted for 67.00%, among which the mixed infection of bacteria and virus (25.99%) was the most common. 78 cases had pulmonary infection, the positive rate of traditional laboratory tests was 42.31% (33/78), and of mNGS in peripheral blood was 73.08% (57/78), showing a statistical difference (P = 0.000). The non-HSCT patients had a higher frequency of Klebsiella pneumonia (OR=0.777, 95% CI, 0.697-0.866, P = 0.01) and Torque teno virus (OR=0.883, 95% CI, 0.820-0.950, P = 0.031) infections than HSCT patients, while the rates of Streptococcus pneumonia (OR=12.828, 95% CI, 1.378-119.367, P = 0.016), Candida pseudosmooth (OR=1.100, 95% CI, 0.987-1.225, P = 0.016), human betaherpesvirus 6B (OR=6.345, 95% CI, 1.105-36.437, P = 0.039) and human polyomavirus 1 (OR=1.100, 95% CI, 0.987-1.225, P = 0.016) infections were lower. Leishmania could be detected by mNGS.

Conclusion

mNGS of peripheral blood can be used as a substitute test method for hematological patients with pulmonary infection, the detection rate of mixed infections by mNGS was high, and mNGS has high clinical recognition rate and sensitivity in pathogen detection, and provides a basis for guiding the anti-infective treatment in hematological diseases with symptoms such as fever.

Clinical and microbiological characteristics of bacterial meningitis in umbilical cord blood transplantation recipients

Bacterial meningitis is a rare but severe infectious complication after hematopoietic stem cell transplantation. However, its clinical features were previously not clear. We reviewed the cases of 7 patients diagnosed with bacterial meningitis with a positive cerebrospinal fluid culture among 1147 patients who underwent cord blood transplantation (CBT) at our institution between September 2007 and September 2020. The diagnosis was made on day + 5- + 45, and 5 patients developed bacterial meningitis before neutrophil engraftment. The causative organisms were all Gram-positive cocci: Enterococcus faecium and Enterococcus gallinarum (2 patients each), and Staphylococcus haemolyticus, Streptococcus mitis/oralis, and Rothia mucilaginosa (1 patient each). Six patients developed bacterial meningitis secondary to prior or concomitant bacteremia caused by the same bacterium. Five patients had received anti-MRSA agents at onset: vancomycin in 3, teicoplanin in 1, and daptomycin in 1. After diagnosis of bacterial meningitis, linezolid was eventually used for 6 patients. Two patients with E. gallinarum were alive at day + 1380 and + 157 after CBT, respectively, whereas 5 patients died 17-53 (median 43) days after the onset of bacterial meningitis. Breakthrough meningitis in CBT can occur even during the use of anti-MRSA drugs, and intensive antibiotic treatment is necessary.

Immunogenicity and safety of the meningococcal B recombinant (4CMenB) vaccine in allogeneic hematopoietic cell transplantation recipients

OBJECTIVES

Despite a high risk of invasive meningococcal (Men) disease, there is no published data on any MenB vaccine after hematopoietic cell transplantation (HCT). We investigated the immunogenicity and safety of the 4CMenB recombinant vaccine (Bexsero®) in adult HCT recipients.

METHODS

Patients were eligible from 6 months post-HCT to receive 2 4CMenB doses at 2 months interval. Sera were collected at baseline, 1 month after the second dose, and 12 months after enrollment. The serum bactericidal activity (SBA) using human complement (hSBA) was assessed against fHbp, NadA, PorAP1.4 and NHBA antigens. The vaccine response was defined by one criteria for one vaccine antigen: (1) In patients with a hSBA titer < 4 at baseline: a titer > 4; (2) In patients with a hSBA titer > 4 at baseline: at least a x4 increase.

RESULTS

40 patients were included at a median of 2.14 (0.57-13.03) years post-transplant. At baseline, most patients (32/40 80%) had hSBA titers < 4 for all vaccine antigens. After 2 vaccine doses, the proportion of patients with a titer > 4 was significantly increased for fHbp (23/40 57.5%), NadA (25/40 62.5%), and PorA (31/40 77.5%) but not for NHBA for which only 6/40 (15%) patients responded. 36/40 (90%) patients were responders to > 1 antigen. However, 9 months later, only 23/37 (62.2%) patients were still seroprotected. No severe adverse event was observed.

CONCLUSION

The response rate of 90% for >1 vaccine antigen and our safety data supports the 4CMenB vaccination of HCT recipients from 6 months after transplant with 2 doses.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.gov, NCT03509051.

Invasive Bacterial Infections in Subjects with Genetic and Acquired Susceptibility and Impacts on Recommendations for Vaccination: A Narrative Review

The WHO recently endorsed an ambitious plan, “Defeating Meningitis by 2030”, that aims to control/eradicate invasive bacterial infection epidemics by 2030. Vaccination is one of the pillars of this road map, with the goal to reduce the number of cases and deaths due to Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus agalactiae. The risk of developing invasive bacterial infections (IBI) due to these bacterial species includes genetic and acquired factors that favor repeated and/or severe invasive infections. We searched the PubMed database to identify host risk factors that increase the susceptibility to these bacterial species. Here, we describe a number of inherited and acquired risk factors associated with increased susceptibility to invasive bacterial infections. The burden of these factors is expected to increase due to the anticipated decrease in cases in the general population upon the implementation of vaccination strategies. Therefore, detection and exploration of these patients are important as vaccination may differ among subjects with these risk factors and specific strategies for vaccination are required. The aim of this narrative review is to provide information about these factors as well as their impact on vaccination against the four bacterial species. Awareness of risk factors for IBI may facilitate early recognition and treatment of the disease. Preventive measures including vaccination, when available, in individuals with increased risk for IBI may prevent and reduce the number of cases.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

Central Nervous System Infections in the Immunocompromised Adult Presenting to the Emergency Department

Over the past 2 decades, the population of immunocompromised patients has increased dramatically in the United States. These patients are at elevated risk for both community-acquired and opportunistic central nervous system infections. We review the most common and serious central nervous system pathogens affecting these patients and outline a diagnostic and therapeutic approach to their management in the emergency department. We recommend a broad diagnostic evaluation, including neuroimaging and cerebrospinal fluid studies where appropriate, empiric antimicrobial therapy, and early involvement of subspecialists to provide comprehensive care for these complex patients.

Immunization Strategies to Span the Spectrum of Immunocompromised Adults

The Advisory Committee on Immunization Practices to the US Centers for Disease Control and Prevention provides annual recommendations for routine adult immunizations. Many recommendations consider patient factors such as age, medical conditions, and medications that increase an individual's risk for infection with a vaccine-preventable disease. These factors, particularly those that lead to immunocompromise, may also alter the risk-benefit ratio for live vaccines, and/or lead to decreased vaccine immunogenicity and effectiveness. The provider may need to consider alternative vaccination strategies, including higher antigen dose vaccines, adjuvanted vaccines, avoidance of live vaccines, and careful timing of vaccination to optimize safety and effectiveness in immunocompromised populations. This thematic review discusses general principles regarding immunization of adults across the spectrum of immunocompromise, examines current guidelines and studies that support them, and outlines future research needs.

Methods for rapid diagnosis of meningitis etiology in adults

Infectious meningitis can be caused by viral, bacterial or fungal pathogens. Despite widely available treatments, many types of infectious meningitis are still associated with significant morbidity and mortality. Delay in diagnosis contributes to poor outcomes. Cerebrospinal fluid cultures have been used traditionally but are time intensive and sensitivity is decreased by empiric treatment prior to culture. More rapid techniques such as the cryptococcal lateral flow assay (IMMY), GeneXpert MTB/Rif Ultra (Cepheid) and FilmArray multiplex-PCR (Biofire) are three examples that have drastically changed meningitis diagnostics. This review will discuss a holistic approach to diagnosing bacterial, mycobacterial, viral and fungal meningitis.

Vaccination of haemopoietic stem cell transplant recipients: guidelines of the 2017 European Conference on Infections in Leukaemia (ECIL 7)

Infection is a main concern after haemopoietic stem cell transplantation (HSCT) and a major cause of transplant-related mortality. Some of these infections are preventable by vaccination. Most HSCT recipients lose their immunity to various pathogens as soon as the first months after transplant, irrespective of the pre-transplant donor or recipient vaccinations. Vaccination with inactivated vaccines is safe after transplantation and is an effective way to reinstate protection from various pathogens (eg, influenza virus and Streptococcus pneumoniae), especially for pathogens whose risk of infection is increased by the transplant procedure. The response to vaccines in patients with transplants is usually lower than that in healthy individuals of the same age during the first months or years after transplant, but it improves over time to become close to normal 2-3 years after the procedure. However, because immunogenic vaccines have been found to induce a response in a substantial proportion of the patients as early as 3 months after transplant, we recommend to start crucial vaccinations with inactivated vaccines from 3 months after transplant, irrespectively of whether the patient has or has not developed graft-versus-host disease (GvHD) or received immunosuppressants. Patients with GvHD have higher risk of infection and are likely to benefit from vaccination. Another challenge is to provide HSCT recipients the same level of vaccine protection as healthy individuals of the same age in a given country. The use of live attenuated vaccines should be limited to specific situations because of the risk of vaccine-induced disease.

Incidence of invasive pneumococcal disease in immunocompromised patients: A systematic review and meta-analysis

BACKGROUND

Invasive pneumococcal disease (IPD) is associated with high morbidity and mortality, with immunocompromised patients (ICPs) at particular risk. Therefore, guidelines recommend pneumococcal vaccination for these patients. However, guidelines are scarcely underpinned with references to incidence studies of IPD in this population. This, potentially results in unawareness of the importance of vaccination and low vaccination rates. The objective of this systematic review and meta-analysis was to assess the incidence of IPD in ICPs.

METHODS

We systematically searched PubMed and Embase to identify studies in English published before December 6th, 2017 that included terms related to 'incidence', 'rate', 'pneumococcal', 'pneumoniae', 'meningitis', 'septicemia', or 'bacteremia'. We focused on patients with HIV, transplantation and chronic inflammatory diseases.

RESULTS

We included 45 studies in the systematic review reporting an incidence or rate of IPD, defined as isolation of Streptococcus pneumoniae from a normally sterile site. Random effects meta-analysis of 38 studies showed a pooled IPD incidence of 331/100,000 person years in patients with HIV in the late-antiretroviral treatment era in non-African countries, and 318/100,000 in African countries; 696 and 812/100,000 in patients who underwent an autologous or allogeneic stem cell transplantation, respectively; 465/100,000 in patients with a solid organ transplantation; and 65/100,000 in patients with chronic inflammatory diseases. In healthy control cohorts, the pooled incidence was 10/100,000.

DISCUSSION

ICPs are at increased risk of contracting IPD, especially those with HIV, and those who underwent transplantation. Based on our findings, we recommend pneumococcal vaccination in immunocompromised patients.

PROSPERO REGISTRATION

ID: CRD42016048438.

Central nervous system infections in immunocompromised patients

PURPOSE OF REVIEW

Although rare, central nervous system (CNS) infections are increasingly being recognized in immunocompromised patients. The goal of the present review is to provide a practical diagnostic approach for the intensivist, and to briefly discuss some of the most prevalent conditions.

RECENT FINDINGS

Immunocompromised patients presenting with new neurological symptoms should always be suspected of a CNS infection. These infections carry a poor prognosis, especially if intracranial hypertension, severely altered mental status or seizures are present. Clinical examination and serum blood tests should be followed by brain imaging, and when no contra-indications are present, a lumbar puncture including cerebrospinal fluid PCR to identify causative organisms. Empirical therapy depends on the type of immunodeficiency. In HIV-infected patients, the most common CNS infection is cerebral toxoplasmosis, whereas in other immunocompromised patients, aspergillosis, cryptococcal meningitis and tuberculous meningitis are more prevalent. Multiple pathogens can be detected in up to 15% of patients. The diagnostic value of fast multiplex PCR has yet to be evaluated in this setting.

SUMMARY

CNS infections represent a rare but severe complication in immunocompromised patients. A systematic approach including early diagnosis, appropriate antimicrobial treatment, early ICU admission and aggressive measures to reduce intracranial pressure may improve outcome.

Community-acquired bacterial meningitis

Meningitis is an inflammation of the meninges and subarachnoid space that can also involve the brain cortex and parenchyma. It can be acquired spontaneously in the community - community-acquired bacterial meningitis - or in the hospital as a complication of invasive procedures or head trauma (nosocomial bacterial meningitis). Despite advances in treatment and vaccinations, community-acquired bacterial meningitis remains one of the most important infectious diseases worldwide. Streptococcus pneumoniae and Neisseria meningitidis are the most common causative bacteria and are associated with high mortality and morbidity; vaccines targeting these organisms, which have designs similar to the successful vaccine that targets Haemophilus influenzae type b meningitis, are now being used in many routine vaccination programmes. Experimental and genetic association studies have increased our knowledge about the pathogenesis of bacterial meningitis. Early antibiotic treatment improves the outcome, but the growing emergence of drug resistance as well as shifts in the distribution of serotypes and groups are fuelling further development of new vaccines and treatment strategies. Corticosteroids were found to be beneficial in high-income countries depending on the bacterial species. Further improvements in the outcome are likely to come from dampening the host inflammatory response and implementing preventive measures, especially the development of new vaccines.