Susceptibility to invasive bacterial infections in children with sickle cell disease

Bone and Joint Infections in Children With Sickle Cell Disease in French Guiana: A 13-Year Retrospective Multicenter Review

INTRODUCTION

Sickle cell disease (SCD) is a genetic disorder with a high infectious morbidity and mortality and a heterogeneous distribution in France. One of the challenges is to differentiate a bone and joint infection (BJI) from a vaso-occlusive crisis. This challenge is particularly prevalent in French Guiana, an overseas territory with the highest incidence of SCD in France. The aim of this study was to describe the epidemiology of BJI in children with SCD in French Guiana.

METHOD

This was a retrospective multicentric descriptive study of SCD patients living in French Guiana aged under 18 and diagnosed with a BJI between 2010 and 2022. These BJI were divided into 2 groups: those with microbiological documentation (d-BJI) and those without microbiological identification (ud-BJI).

RESULTS

A total of 53 episodes of BJI in 42 patients (mean age 7.2 years) were reported. Clinical symptoms on arrival were comparable between the d-BJI and ud-BJI groups. Patients in the d-BJI group had longer average hospital stays (40.4 days vs. 16.8 days, P = 0.01) and Salmonella spp. were the most identified bacteria (n = 8/13). White blood cell count was greater in the d-BJI group (30.3 G/L vs. 18.G/L, P = 0.01) and a collection was more frequently identified on imaging (11/13 vs. 16/40, P = 0.01) in this group. Initial in-hospital antibiotic therapy was longer in the d-BJI group (17.2 days vs. 12.8, P = 0.02), as were infection-related complications (9/13 vs. 12/40 P = 0.01).

CONCLUSION

BJI in children with SCD is not sufficiently microbiologically documented. Progress must be made to improve the documentation of BJI.

Indicators for Osteomyelitis in Children With Sickle Cell Disease Admitted With Vaso-Occlusive Crises

INTRODUCTION

Sickle cell disease (SCD) is an autosomal recessive genetic disorder characterized by the presence of a mutated form of hemoglobin (Hb) known as sickle hemoglobin (HbS). Individuals with SCD are susceptible to a variety of osteoarticular complications. Osteomyelitis is a commonly seen infection affecting the tibia, diaphysis of the femur and humerus, and vertebras.

AIM

The aim of this study was to define the indicators suggesting the diagnosis of osteomyelitis in patients with SCD.

METHODS

This study is a descriptive, analytical, non-interventional, prospective study of pediatric patients with SCD admitted with vaso-occlusive crisis (VOC) and/or osteomyelitis, which were identified by laboratory and radiological features. Retrospective data was included for patients who met the inclusion criteria. The statistical analysis included a description of the primary and secondary outcomes in the cohort.

RESULTS

A total of 28 children were included in this study. Participants' ages ranged from 11 months to 13 years. Males represented the majority (64.3%) of the participants. The blood culture of most of the participants (89.3%) showed no growth; however, 7.1% had salmonella, and only 3.6% had Gram-positive cocci. Most cases (75%) had leukocytosis. Thrombocytosis was present mainly in patients with VOC (40%). CRP was 1-4.9 mg/dL, mainly in patients with osteomyelitis (50%). The ferritin level exceeded 5000 ng/mL in patients with osteomyelitis or both osteomyelitis and VOC (50%). Ultrasound examinations revealed no hip effusion in 24 of the 28 examined patients. A plain X-ray examination showed no abnormality in 24 out of the 28 examined cases; with MRI, three cases exhibited marrow edema with bone enhancement, two (66.7%) were complicated by osteomyelitis, and the last (33.3%) had osteomyelitis and VOC. Aspiration was performed only in seven of the 28 examined, of which six (85.7%) were complicated by osteomyelitis, while the last one (14.3%) had acute chest syndrome.

CONCLUSION

Based on the outcomes of this study, we recommend an individualized multidisciplinary examination (hematology, infectious disease, orthopedic surgery, and interventional radiology) for SCD patients with suspected osteomyelitis admitted with VOC, considering the entire clinical history and laboratory and MRI results.

PCV15, a pneumococcal conjugate vaccine, for the prevention of invasive pneumococcal disease in infants and children

INTRODUCTION

Streptococcus pneumoniae is a causative agent of pneumonia and acute otitis media (AOM), as well as invasive diseases such as meningitis and bacteremia. PCV15 (V114) is a new 15-valent pneumococcal conjugate vaccine (PCV) approved for use in individuals ≥6 weeks of age for the prevention of pneumonia, AOM, and invasive pneumococcal disease.

AREAS COVERED

This review summarizes the V114 Phase 3 development program leading to approval in infants and children, including pivotal studies, interchangeability and catch-up vaccination studies, and studies in at-risk populations. An integrated safety summary is presented in addition to immunogenicity and concomitant use of V114 with other routine pediatric vaccines.

EXPERT OPINION

Across the development program, V114 demonstrated a safety profile that is comparable to PCV13 in infants and children. Immunogenicity of V114 is comparable to PCV13 for all shared serotypes except serotype 3, where V114 demonstrated superior immunogenicity. Higher immune responses were demonstrated for V114 serotypes 22F and 33F. Results of the ongoing study to evaluate V114 efficacy against vaccine-type pneumococcal AOM and anticipated real-world evidence studies will support assessment of vaccine effectiveness and impact, with an additional question of whether higher serotype 3 immunogenicity translates to better protection against serotype 3 pneumococcal disease.

Molecular characterization of Streptococcus pneumoniae causing disease among children in Nigeria during the introduction of PCV10 (GSK)

Streptococcus pneumoniae (pneumococcus) is a leading vaccine-preventable cause of childhood invasive disease. Nigeria has the second highest pneumococcal disease burden globally, with an estimated ~49 000 child deaths caused by pneumococcal infections each year. Ten-valent pneumococcal conjugate vaccine (GSK; PCV10) was introduced in December 2014 in a phased approach. However, few studies have characterized the disease-causing pneumococci from Nigeria. This study assessed the prevalence of serotypes, antibiotic susceptibility and genomic lineages using whole genome sequencing and identified lineages that could potentially escape PCV10 (GSK). We also investigated the potential differences in pneumococcal lineage features between children with and without sickle cell disease. A collection of 192 disease-causing pneumococcal isolates was obtained from Kano (n=189) and Abuja (n=3) states, Nigeria, between 1 January 2014 and 31 May 2018. The majority (99 %, 190/192) of specimens were recovered from children aged 5 years or under. Among them, 37 children had confirmed or traits of sickle cell disease. Our findings identified 25 serotypes expressed by 43 Global Pneumococcal Sequence Clusters (GPSCs) and 85 sequence types (STs). The most common serotypes were 14 (18 %, n=35), 6B (16 %, n=31), 1 (9 %, n=17), 5 (9 %, n=17) and 6A (9 %, n=17); all except serotype 6A are included in PCV10 (GSK). PCV10 (SII; PNEUMOSIL) and PCV13 formulations include serotypes 6A and 19A which would increase the overall coverage from 67 % by PCV10 (GSK) to 78 and 82 %, respectively. The pneumococcal lineages were a mix of globally spreading and unique local lineages. Following the use of PCV10 (GSK), GPSC5 expressing serotype 6A, GPSC10 (19A), GPSC26 (12F and 46) and GPSC627 (9L) are non-vaccine type lineages that could persist and potentially expand under vaccine-selective pressure. Approximately half (52 %, 99/192) of the pneumococcal isolates were resistant to the first-line antibiotic penicillin and 44 % (85/192) were multidrug-resistant. Erythromycin resistance was very low (2 %, 3/192). There was no significant difference in clinical manifestation, serotype prevalence or antibiotic resistance between children with and without traits of or confirmed sickle cell disease. In summary, our findings show that a high percentage of the pneumococcal disease were caused by the serotypes that are covered by currently available vaccines. Given the low prevalence of resistance, macrolide antibiotics, such as erythromycin, should be considered as an option to treat pneumococcal disease in Nigeria. However, appropriate use of macrolide antibiotics should be vigilantly monitored to prevent the potential increase in macrolide resistance.

The Prevalence of the Virulence Genes of Staphylococcus aureus in Sickle Cell Disease Patients at KSUMC, Riyadh, Saudi Arabia

Staphylococcus aureus in the blood of sickle cell disease (SCD) patients may result in a significant increase in morbidity and mortality. S. aureus strains contain various virulence characteristics, including the ability to create a variety of toxins and develop drug resistance. The current study sought to assess the prevalence of S. aureus in SCD patients and to identify the pathogen's virulence characteristics. Between 2017 and 2021, blood samples and data were collected at King Saud University Medical City (KSUMC) in Riyadh, Saudi Arabia. The Vitek system PCR and gene sequencing methods were used for identification, antibiotic resistance patterns, and genetic analysis. During the study period, 47 S. aureus blood isolates (methicillin-resistant S. aureus (MRSA) 41.6% and non-MRSA 58.4%) were isolated from 2406 SCD patients. The prevalence percentages of virulence genes (finbB, sdrC, sdrD, icaA, coa, nuc, hlg, hla, finbA, clfA, efb, pvl, agr, spa, seb, sea, sec, tst, and sed) among all the isolates from the SCD patients compared with non-SCD patients (control group) were as follows: (100% vs. 100%), (100% vs. 100%), (100% vs. 100%), (100% vs. 87.5%), (100% vs. 81.3%), (100% vs. 100%), (100% vs. 100%), (100% vs. 100%), (97.9% vs. 81.3%), (97.9% vs. 100%), (97.9% vs. 87.5%), (54.3% vs. 56.3%), (46.8% vs. 75%), (42.6% vs. 43.8%), (27.7% vs. 0%), (25.5% vs. 12.5%), (12.8% vs. 6.3%), (4.3% vs. 12.5%), and (4.3% vs. 0%). Regarding the resistance genes (plaZ, mecA, ermA, ermC, tetK, tetM, and ermB) of the S. aureus strains isolated from the SCD patients compared with non-SCD patients (control group), the prevalence percentages were as follows: (100% vs. 100%), (100% vs. 56.3%), (0% vs. 31.3%), (31.9% vs. 18.8%), (40.4% vs. 25%), (0% vs. 0%), and (0% vs. 0%). As for the antibiotic (ampicillin, penicillin, amoxicillin, cefazolin, imipenem, oxacillin, erythromycin, tetracycline, azithromycin, ciprofloxacin, moxifloxacin, and levofloxacin) resistance of the S. aureus strains isolated from the SCD patients compared with non-SCD patients (control group), the prevalence percentages were as follows: (100% vs. 100%), (97.9% vs. 100%), (72.3% vs. 25%), (68.1% vs. 37.5%), (68.1% vs. 25%), (66% vs. 25%), (36.2% vs. 18.8%), (23.4% vs. 12.5%), (19.1% vs. 12.5%), (17% vs. 12.5%), (14.9% vs. 25%), and (10.6% vs. 18.7%). This study concluded that several virulence genes were present in the S. aureus strains recovered from the SCD patients at KSUMC, with all the isolates containing the finbB, sdrC, sdrD, icaA, coa, nuc, hlg, and hla genes.

Operationalizing Appropriate Sepsis Definitions in Children Worldwide: Considerations for the Pediatric Sepsis Definition Taskforce

Sepsis is a leading cause of global mortality in children, yet definitions for pediatric sepsis are outdated and lack global applicability and validity. In adults, the Sepsis-3 Definition Taskforce queried databases from high-income countries to develop and validate the criteria. The merit of this definition has been widely acknowledged; however, important considerations about less-resourced and more diverse settings pose challenges to its use globally. To improve applicability and relevance globally, the Pediatric Sepsis Definition Taskforce sought to develop a conceptual framework and rationale of the critical aspects and context-specific factors that must be considered for the optimal operationalization of future pediatric sepsis definitions. It is important to address challenges in developing a set of pediatric sepsis criteria which capture manifestations of illnesses with vastly different etiologies and underlying mechanisms. Ideal criteria need to be unambiguous, and capable of adapting to the different contexts in which children with suspected infections are present around the globe. Additionally, criteria need to facilitate early recognition and timely escalation of treatment to prevent progression and limit life-threatening organ dysfunction. To address these challenges, locally adaptable solutions are required, which permit individualized care based on available resources and the pretest probability of sepsis. This should facilitate affordable diagnostics which support risk stratification and prediction of likely treatment responses, and solutions for locally relevant outcome measures. For this purpose, global collaborative databases need to be established, using minimum variable datasets from routinely collected data. In summary, a "Think globally, act locally" approach is required.

Bacterial Infection in the Sickle Cell Population: Development and Enabling Factors

The high frequency of bacterial infections represents a major threat to public health. In developing countries, they are still responsible for significant morbidity and mortality in pediatric populations with sickle cell disease, particularly in children under 5 years of age. Indeed, they have an increased susceptibility to bacterial infections due to their immune deficiency. This susceptibility is even greater for pneumococcal and salmonella infections. In addition, the underdevelopment of some countries and socio-economic factors increases this condition. This review examines the common and specific factors leading to infections in people with sickle cell disease in different types of developed and undeveloped countries. The threat of bacterial infections, particularly those caused by S. pneumoniae and Salmonella, is of increasing concern due to the rise in bacterial resistance to antibiotics. In light of this disturbing data, new strategies to control and prevent these infections are needed. Solutions could be systematic penicillin therapy, vaccinations, and probabilistic antibiotic therapy protocols.

Bacterial meningitis in adults: a retrospective study among 148 patients in an 8-year period in a university hospital, Finland

BACKGROUND

Bacterial meningitis (BM) causes significant morbidity and mortality. We investigated predisposing factors, clinical characteristics, spectrum of etiological bacteria, and clinical outcome of community-acquired and nosocomial BM.

METHODS

In this retrospective study we analyzed data of 148 adults (age > 16 years) with BM treated in Turku University Hospital, Southwestern Finland, from 2011 to 2018. Besides culture- or polymerase chain reaction (PCR)-positive cases we also included culture-negative cases with laboratory parameters strongly suggestive of BM and those with meningitis-related findings in imaging. We used Glasgow Outcome Scale (GOS) score 1-4 to determine unfavorable outcome.

RESULTS

The median age of patients was 57 years and 48.6% were male. Cerebrospinal fluid (CSF) culture for bacteria showed positivity in 50 (33.8%) cases, although pre-diagnostic antibiotic use was frequent (85, 57.4%). The most common pathogens in CSF culture were Streptococcus pneumoniae (11, 7.4%), Staphylococcus epidermidis (7, 4.7%), Staphylococcus aureus (6, 4.1%) and Neisseria meningitidis (6, 4.1%). Thirty-nine patients (26.4%) presented with the triad of fever, headache, and neck stiffness. A neurosurgical procedure or an acute cerebral incident prior BM was recorded in 74 patients (50%). Most of the patients had nosocomial BM (82, 55.4%) and the rest (66, 44.6%) community-acquired BM. Ceftriaxone and vancomycin were the most used antibiotics. Causative pathogens had resistances against the following antibiotics: cefuroxime with a frequency of 6.8%, ampicillin (6.1%), and tetracycline (6.1%). The case fatality rate was 8.8% and the additional likelihood of unfavorable outcome 40.5%. Headache, decreased general condition, head computed tomography (CT) and magnetic resonance imaging (MRI), hypertension, altered mental status, confusion, operative treatment, neurological symptoms, pre-diagnostic antibiotic use and oral antibiotics on discharge were associated with unfavorable outcome.

CONCLUSIONS

The number of cases with nosocomial BM was surprisingly high and should be further investigated. The usage of pre-diagnostic antibiotics was also quite high. Headache was associated with unfavorable outcome. The frequency of unfavorable outcome of BM was 40.5%, although mortality in our patients was lower than in most previous studies.

Safety and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine, in children with SCD: a V114-023 (PNEU-SICKLE) study

Sickle cell disease (SCD) is an inherited red blood cell disease that results in a multitude of medical complications, including an increased risk of invasive disease caused by encapsulated bacteria, such as Streptococcus pneumoniae. Pneumococcal vaccines have contributed to a significant reduction in pneumococcal disease (PD) in children and adults, including those with SCD. This phase 3 study evaluated the safety and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine (PCV), in children with SCD. A total of 103 children aged 5 to 17 years with SCD were randomized and received a single dose of V114 or Prevnar 13 (PCV13). Safety was evaluated as the proportion of participants with adverse events (AEs). Serotype-specific immunoglobulin G (IgG) levels and opsonophagocytic activity (OPA) were measured immediately before vaccination and 30 days after vaccination. Overall, the rates of injection-site and systemic AEs reported after vaccination were similar between the vaccination groups. Up to 6 months after vaccination, serious AEs were those expected for patients with SCD, and none were assessed to be vaccine related. IgG geometric mean concentrations (GMCs) and OPA geometric mean titers (GMTs) for the 13 shared serotypes were generally comparable between recipients of V114 and PCV13. Additionally, V114 induced immune responses to serotypes 22F and 33F, which are not included in PCV13. The safety and tolerability profiles of V114 were consistent with those reported for PCV13. Immune responses following vaccination with V114 were generally comparable to PCV13 for the shared serotypes and higher for unique serotypes 22F and 33F. These results support the use of V114 in children with SCD. This trial was registered at www.clinicaltrials.gov as #NCT03731182.

Assessment of humoral immunity and nutritionally essential trace elements in steady-state sickle cell disease Nigerian children before and after Prevenar 13 pneumococcal vaccination

Children with sickle cell disease (SCD) are particularly prone to pneumococcal infection and administration of Prevenar 13 pneumococcal vaccine in Nigerian children with SCD is yet to be wide spread. This call for the need to study humoral immune responses stimulated by Prevenar 13 pneumococcal vaccine in SCD children to confirm the benefit or otherwise for the use of Prevenar 13 pneumococcal vaccine.

Method

The levels of humoral (innate and adaptive) immune factors and associated nutritionally essential trace elements were determined following Prevenar 13 pneumococcal vaccination of 23 Nigerian children with SCD. Serum innate humoral immune factors [Complement factors (C1q and C4), transferrin, ferritin, and C-reactive protein (CRP)] and adaptive humoral immune factors [IgG, IgA, IgM, and IgE] were determined using ELISA. Nutritionally essential trace elements such as iron (Fe), copper (Cu), and zinc (Zn) were measured also using an atomic absorption spectrophotometer.

Results

The serum levels of certain innate humoral immune factors (ferritin, CRP, and C4), only one adaptive humoral immune factors (IgE), and essential trace elements (Fe, Zn, and Cu) were significantly elevated in children with SCD post Prevenar 13 pneumococcal vaccination when compared to prevaccination levels.

Conclusion

Vaccination of children with SCD with Prevenar 13 pneumococcal vaccine was associated with increased levels of more innate humoral immune factors than adaptive factors. This study thus supports the administration of Prevenar 13 pneumococcal vaccination to children with SCD.

Bloodstream Infections in Children With Sickle Cell Disease: 2010-2019

BACKGROUND

Children with sickle cell disease (SCD) are at increased risk for bloodstream infections (BSIs), mainly because of functional asplenia. Immunizations and antibiotic prophylaxis have reduced the prevalence of invasive bacterial infections, but contemporary analysis of BSI in children with SCD is limited.

METHODS

We conducted a retrospective cohort study of children aged <18 years with SCD who had blood cultures collected at our institution from 2010 to 2019 to identify BSI. Probable contaminant organisms were identified and not included as BSI. We calculated the annual incidence of BSI at our institution with 95% confidence intervals (CIs) and used multivariate logistic regression to evaluate associations.

RESULTS

There were 2694 eligible patients with 19 902 blood cultures. Excluding repeated cultures and contaminant cultures, there were 156 BSI episodes in 144 patients. The median age at BSI was 7.5 years. The average incidence rate of BSI was 0.89 per 100 person-years (95% CI 0.45-1.32). The most common pathogens were Streptococcus pneumoniae (16.0%), Streptococcus viridans group (9.0%), Escherichia coli (9.0%), Staphylococcus aureus (7.7%), Bordetella holmesii (7.7%), Haemophilus influenzae (7.1%), and Salmonella species (6.4%). Odds of BSI were higher with sickle cell anemia genotypes (odds ratio [OR] 1.88; 95% CI 1.20-2.94) and chronic transfusions (OR 2.66; 95% CI 1.51-4.69) and lower with hydroxyurea (OR 0.57; 95% CI 0.39-0.84).

CONCLUSIONS

BSI remains a risk for children with SCD. Overall incidence, risk factors, and spectrum of pathogens are important considerations to guide prevention and empirical treatment of suspected infection in SCD.

Profile of bacterial pathogens causing infections in children with sickle cell anaemia in Maiduguri

Background

Sickle cell disease (SCD) is a major cause of morbidity and mortality in African children. Infection has been found to be a major cause of hospitalisation, a major precipitant of crises and one of the greatest causes of death among SCD patients at all ages.

Objectives

The objective of the study was to determine the prevalence of bacterial infection, pattern of the isolates and the antibiotic sensitivity of isolated bacteria among children with sickle cell anaemia (SCA).

Materials and Methods

A cross-sectional study carried out in the University of Maiduguri Teaching Hospital. A total of 242 hospitalised children with SCA with symptoms and signs of infection were recruited for the study using consecutive sampling technique. Sociodemographic and clinical data were obtained. Blood, urine, aspirates, swabs and cerebrospinal fluid samples were collected based on their clinical presentation and subjected to microbiological analysis.

Results

A total of 242 patients were studied. The age range was 9 months-15 years, with a mean age of 6.36 years ± 3.75 years. Male-to-female ratio was 1:1.14, with 41.7% of them belonging to low social class. Seventy seven of the 242 had confirmed bacterial infection giving an incidence of bacterial infection in SCA patients of 31.8%. Gram-negative organisms accounted for 64.5% of the isolates and they include Salmonella, Klebsiella, Escherichia coli and Coliforms. However, Staphylococcus aureus (32.9%) was the most frequent microorganism isolated, followed by Salmonella, (20.3%), Klebsiella (12.6%) and Coliforms (12.6%). Amoxicillin-clavulanate, cefixime and gentamicin showed more than 50% activity against the isolated bacterial pathogens while chloramphenicol was found to have low activity against Salmonella.

Conclusion

High index of suspicion of bacterial infection should be borne in mind of the attending physician when children with SCA present with features of infection. Detailed clinical evaluation and appropriate sample collection for microbiological analysis are recommended. Empirical treatment should be started on SCA patients who have clinical evidence of infection and should be broad enough to cover for common bacterial pathogens.

Emergence of gram-negative organisms as the cause of infections in patients with sickle cell disease

BACKGROUND

Patients with sickle cell disease are at higher risk of infections with encapsulated bacteria due to immature immune responses and functional asplenia. We aimed to study our patient population for the emergence of gram-negative organisms other than Salmonella as the cause of osteomyelitis and document a vast decrease in Streptococcus pneumoniae bacteremia rates.

METHODS

We conducted a retrospective chart review of 158 patients with sickle cell disease registered at our hospital. Over a period of 13 years, every patient presenting to the emergency department (ED) with fever had their medical record reviewed for blood cultures, wound cultures, and magnetic resonance imaging results for osteomyelitis.

RESULTS

The number of patients presenting to the ED with fever was 105, with 581 febrile episodes and 893 blood cultures. Among those, no culture grew Streptococcus pneumoniae, 14 grew coagulase-negative staphylococci (1.5%), one grew Salmonella enterica Paratyphi B, and three grew Salmonella enterica group C (in the same patient). The total number of osteomyelitis episodes in patients with sickle cell disease presenting with fever and documented by imaging was nine (1.5%). In patients with osteomyelitis, organisms were isolated in four patients (44%), including Enterobacter cloacae, Bacteroides, Pseudomonas aeruginosa, and Salmonella enterica group C.

CONCLUSIONS

Immunization against Streptococcus pneumoniae and the use of prophylactic penicillin has virtually eliminated pneumococcal bacteremia among our patients. We observed the emergence of gram-negative organisms other than Salmonella as the cause of osteomyelitis in patients with sickle cell disease.

Influenza vaccine effectiveness and disease burden in children and adolescents with sickle cell disease: 2012-2017

BACKGROUND

Data are limited on the burden of influenza and seasonal influenza vaccine effectiveness (VE) in children with sickle cell disease (SCD).

METHODS

We used a prospectively collected clinical registry of SCD patients 6 months to 21 years of age to determine the influenza cases per 100 patient-years, vaccination rates, and a test-negative case-control study design to estimate influenza VE against medically attended laboratory-confirmed influenza infection. Influenza-positive cases were randomly matched to test-negative controls on age and influenza season in 1:1 ratio. We used adjusted logistic regression models to compare odds ratio (OR) of vaccination in cases to controls. We calculated VE as [100% × (1 - adjusted OR)] and computed 95% confidence intervals (CIs) around the estimate.

RESULTS

There were 1037 children with SCD who were tested for influenza, 307 children (29.6%) had at least one influenza infection (338 infections, incidence rate 3.7 per 100 person-years; 95% CI, 3.4-4.1) and 56.2% of those tested received annual influenza vaccine. Overall VE pooled over five seasons was 22.3% (95% CI, -7.3% to 43.7%). Adjusted VE estimates ranged from 39.7% (95% CI, -70.1% to 78.6%) in 2015/2016 to -5.9% (95% CI, -88.4% to 40.4%) in the 2016/17 seasons. Influenza VE varied by age and was highest in children 1-5 years of age (66.6%; 95% CI, 30.3-84.0). Adjusted VE against acute chest syndrome during influenza infection was 39.4% (95% CI, -113.0 to 82.8%).

CONCLUSIONS

Influenza VE in patients with SCD varies by season and age. Multicenter prospective studies are needed to better establish and monitor influenza VE among children with SCD.

Heme oxygenase-1 in protozoan infections: A tale of resistance and disease tolerance

Heme oxygenase (HO-1) mediates the enzymatic cleavage of heme, a molecule with proinflammatory and prooxidant properties. HO-1 activity deeply impacts host capacity to tolerate infection through reduction of tissue damage or affecting resistance, the ability of the host to control pathogen loads. In this Review, we will discuss the contribution of HO-1 in different and complex protozoan infections, such as malaria, leishmaniasis, Chagas disease, and toxoplasmosis. The complexity of these infections and the pleiotropic effects of HO-1 constitute an interesting area of study and an opportunity for drug development.

Current and emerging treatments for sickle cell disease

Sickle cell disease (SCD) is a group of inherited blood disorders affecting the hemoglobin, shortening the lifespan of erythrocytes, and causing them to take on a distinctive sickled shape that can lead to vaso-occlusion. Current treatment aims to reduce morbidity and mortality through hydroxyurea, erythrocyte transfusion, and hematopoietic stem cell transplantation. This article reviews the disease process, typical presentations, complications, and acute and chronic treatment options.

Incidence of invasive Haemophilus influenzae infections in children with sickle cell disease

BACKGROUND

Children with sickle cell disease (SCD) are at increased risk for invasive infection with encapsulated bacteria. Antibiotic prophylaxis and immunizations against Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) have decreased the overall incidence of invasive infections and have shifted distribution of serotypes causing disease toward those not covered by immunizations. We sought to determine the current incidence of invasive H. influenzae infections in children with SCD and to describe the clinical features and management of these infections.

METHODS

Microbiology reports of a large pediatric tertiary care center were reviewed to identify all isolates of H. influenzae detected in sterile body fluid cultures from January 1, 2010 to December 31, 2017. Results were compared with the center's comprehensive clinical database of all children with SCD to identify all cases of children ages 0 to18 years with SCD with invasive H. influenzae disease for the same time period.

RESULTS

We captured 2444 patients with SCD, with 14,336 person-years. There were eight episodes of H. influenzae bacteremia in seven children with SCD (five type f, two non-typable, one type a). Most episodes (7 of 8) were in children < 5 years. The incidence rate of invasive H. influenzae in SCD was 0.58/1000 person-years for ages 0 to 18 years and 1.60/1000 person-years for children age < 5 years. There were no deaths from H. influenzae infection.

CONCLUSIONS

In the era of universal antibiotic prophylaxis and immunization against Hib, invasive H. influenzae disease due to nonvaccine serotypes remains a risk for children with SCD, particularly those under five years of age.

Sickle cell disease: Clinical presentation and management of a global health challenge

Sickle cell disease is an autosomal recessive, multisystem disorder, characterised by chronic haemolytic anaemia, painful episodes of vaso-occlusion, progressive organ failure and a reduced life expectancy. Sickle cell disease is the most common monogenetic disease, with millions affected worldwide. In well-resourced countries, comprehensive care programs have increased life expectancy of sickle cell disease patients, with almost all infants surviving into adulthood. Therapeutic options for sickle cell disease patients are however, still scarce. Predictors of sickle cell disease severity and a better understanding of pathophysiology and (epi)genetic modifiers are warranted and could lead to more precise management and treatment. This review provides an extensive summary of the pathophysiology and management of sickle cell disease and encompasses the characteristics, complications and current and future treatment options of the disease.

Global, regional, and national burden of meningitis, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

BACKGROUND

Acute meningitis has a high case-fatality rate and survivors can have severe lifelong disability. We aimed to provide a comprehensive assessment of the levels and trends of global meningitis burden that could help to guide introduction, continuation, and ongoing development of vaccines and treatment programmes.

METHODS

The Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 study estimated meningitis burden due to one of four types of cause: pneumococcal, meningococcal, Haemophilus influenzae type b, and a residual category of other causes. Cause-specific mortality estimates were generated via cause of death ensemble modelling of vital registration and verbal autopsy data that were subject to standardised data processing algorithms. Deaths were multiplied by the GBD standard life expectancy at age of death to estimate years of life lost, the mortality component of disability-adjusted life-years (DALYs). A systematic analysis of relevant publications and hospital and claims data was used to estimate meningitis incidence via a Bayesian meta-regression tool. Meningitis deaths and cases were split between causes with meta-regressions of aetiological proportions of mortality and incidence, respectively. Probabilities of long-term impairment by cause of meningitis were applied to survivors and used to estimate years of life lived with disability (YLDs). We assessed the relationship between burden metrics and Socio-demographic Index (SDI), a composite measure of development based on fertility, income, and education.

FINDINGS

Global meningitis deaths decreased by 21·0% from 1990 to 2016, from 403 012 (95% uncertainty interval [UI] 319 426-458 514) to 318 400 (265 218-408 705). Incident cases globally increased from 2·50 million (95% UI 2·19-2·91) in 1990 to 2·82 million (2·46-3·31) in 2016. Meningitis mortality and incidence were closely related to SDI. The highest mortality rates and incidence rates were found in the peri-Sahelian countries that comprise the African meningitis belt, with six of the ten countries with the largest number of cases and deaths being located within this region. Haemophilus influenzae type b was the most common cause of incident meningitis in 1990, at 780 070 cases (95% UI 613 585-978 219) globally, but decreased the most (-49·1%) to become the least common cause in 2016, with 397 297 cases (291 076-533 662). Meningococcus was the leading cause of meningitis mortality in 1990 (192 833 deaths [95% UI 153 358-221 503] globally), whereas other meningitis was the leading cause for both deaths (136 423 [112 682-178 022]) and incident cases (1·25 million [1·06-1·49]) in 2016. Pneumococcus caused the largest number of YLDs (634 458 [444 787-839 749]) in 2016, owing to its more severe long-term effects on survivors. Globally in 2016, 1·48 million (1·04-1·96) YLDs were due to meningitis compared with 21·87 million (18·20-28·28) DALYs, indicating that the contribution of mortality to meningitis burden is far greater than the contribution of disabling outcomes.

INTERPRETATION

Meningitis burden remains high and progress lags substantially behind that of other vaccine-preventable diseases. Particular attention should be given to developing vaccines with broader coverage against the causes of meningitis, making these vaccines affordable in the most affected countries, improving vaccine uptake, improving access to low-cost diagnostics and therapeutics, and improving support for disabled survivors. Substantial uncertainty remains around pathogenic causes and risk factors for meningitis. Ongoing, active cause-specific surveillance of meningitis is crucial to continue and to improve monitoring of meningitis burdens and trends throughout the world.

FUNDING

Bill & Melinda Gates Foundation.

Risk of Invasive Pneumococcal Disease in Children with Sickle Cell Disease in England: A National Observational Cohort Study, 2010-2015

OBJECTIVE

To describe the clinical presentation, risk factors, serotype distribution and outcomes of invasive pneumococcal disease (IPD) in children with sickle cell disease (SCD) following the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) in the UK.

DESIGN

Prospective national newborn screening for SCD and enhanced national IPD surveillance.

PARTICIPANTS

Children with SCD born in England between 1 September 2010 and 31 August 2014 who developed laboratory-confirmed IPD by 31 December 2015.

MAIN OUTCOMES AND MEASURES

Risk of IPD in children with SCD compared with children without SCD during the surveillance period.

RESULTS

Eleven children homozygote for haemoglobin S (HbSS) and one double heterozygote for haemoglobin S and C (HbSC) developed IPD. Septicaemia (n=7) and lower respiratory tract infection (n=4) were the main clinical presentations, and serogroup 15 (not present in PCV13) was responsible for 73% (8/11) of cases. Three children with HbSS (27%) died compared with <5% nationally. Children with HbSS had a 49-fold (95% CI 27 to 89, P<0.001) higher risk of IPD compared with their peers without SCD.

CONCLUSIONS

Children with SCD remain at increased risk of IPD despite national newborn screening, early penicillin prophylaxis and high pneumococcal vaccine uptake. They are also more likely to die of their infection compared with their peers without SCD. Most IPD cases are now due to serotypes not covered by PCV13. Healthcare professionals need to work more closely with families with SCD and local communities to emphasise the importance of penicillin prophylaxis, explore barriers, allay misguided beliefs and facilitate rapid access to healthcare.

Population Pharmacokinetics of Cefotaxime and Dosage Recommendations in Children with Sickle Cell Disease

The pharmacokinetic profile of most drugs is dependent on the patient's covariates and may be influenced by the disease. Cefotaxime is frequently prescribed in pediatric patients with sickle cell disease (SCD), characterized by vaso-occlusive complications, chronic hemolytic anemia, and a defective immunological function predisposing the individual to severe infection. Data on the impact of the disease on the disposition of cefotaxime are missing. In the present study, our aims were to determine cefotaxime pharmacokinetics when prescribed to children with SCD for suspected or proven bacterial infection, identify significant covariates, and perform Monte Carlo simulations to optimize the drug dosage. Cefotaxime serum concentrations were measured in 78 pediatric SCD patients receiving cefotaxime intravenously at a daily dose of 200 mg/kg of body weight in three or four divided doses over 30 min. A total of 107 concentrations were available for pharmacokinetic analysis. A population pharmacokinetic model was developed with NONMEM software and used for Monte Carlo simulations. Cefotaxime concentrations ranged from 0.05 to 103.7 mg/liter. Cefotaxime pharmacokinetics were best described by a one-compartment model: the median estimated weight-normalized volume of distribution and clearance were 0.42 liter/kg (range, 0.2 to 1.1 liter/kg) and 0.38 liter/h/kg (range, 0.1 to 1.2 liter/h/kg). Cefotaxime clearance increased by 22% in patients with acute chest syndrome. Dosing optimization, performed using EUCAST MIC susceptibility breakpoints, showed that a dose of 100 mg/kg/6 h should be used, depending on the patient's characteristics and clinical presentation, in order to reach a value of the percentage of time that the drug concentration exceeded the MIC under steady-state pharmacokinetic conditions of 80% in 80% of the patients when targeting sensitive Gram-positive cocci and Gram-negative bacilli with MICs of 1 mg/liter or below.

Effects of vaccines in patients with sickle cell disease: a systematic review protocol

INTRODUCTION

Sickle cell disease (SCD) is an inherited haematological disorder caused by a single point mutation (Glub6Val) that promotes polymerisation of haemoglobin S and sickling of erythrocytes. Inflammation, haemolysis, microvascular obstruction and organ damage characterise the highly variable clinical expression of SCD. People with SCD are at increased risk of severe infections, hence the need for vaccination against common disease-causing organisms in this population. We aim to review the evidence on the efficacy and safety of vaccines in people with SCD.

METHODS AND ANALYSIS

The present systematic review will examine the current data as indexed in PubMed, CENTRAL, EMBASE and EBSCOHost. We will consult Strategic Advisory Group of Experts practice statements, conference abstracts, reference lists of relevant articles, WHO ICTRP trial registry and experts in the field. Two authors will independently screen search outputs, select studies, extract data and assess risk of bias; resolving discrepancies by discussion and consensus between the two authors or arbitration by a third author when necessary. We will perform a meta-analysis for clinically homogenous studies. Evidence from clinically diverse studies will be aggregated using narrative synthesis of the findings. In either case, we will use the GRADE approach to assess the strength of the available evidence.

ETHICS AND DISSEMINATION

The study draws on data that are readily available in the public domain, hence no formal ethical review and approval is required. The findings of this review will be disseminated through conference presentations and a publication in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42018084051.

Pantoea Species Bacteremia in a Child With Sickle Cell Disease: Looking for a Culprit

Pantoea agglomerans has been classically associated with cellulitis or synovitis secondary to penetrating trauma by vegetation. It is an infrequent cause of systemic infections. We describe the case of a 5-year-old girl with sickle cell disease with P. agglomerans bacteremia and review its potential causes.

Tuberculosis in children with sickle cell anaemia: a retrospective study in French tertiary care centres

Tuberculosis (TB) and sickle cell anaemia (SCA) may affect the same population of patients, particularly in Africa but also in high-TB incidence areas in developed countries. However, few data are available from children with SCA who develop TB. The aim of this study was to describe the clinical features and outcome of TB diagnosed in children with SCA. We conducted a retrospective, descriptive study in three referral centre of Sickle Cell Disease in Paris, France. We included 11 patients with SCA who develop TB. The median age at TB diagnosis was 11 years [7.5-14.5]. Two patients were asymptomatic and nine patients were symptomatic. Six patients had pulmonary TB (pulmonary, pleural and mediastinal lesions). Five patients had extrapulmonary TB (osteoarticular TB, hepatic TB, cervical and mediastinal TB). Mycobacterium tuberculosis was isolated in four of the 11 cases. All patients recovered after a median of 6 months of anti-TB treatment. The localisation of TB and outcome after treatment in our SCA patients were similar to the one observed in an age-and sex-matched control group of non-SCA patient with TB.

CONCLUSION

despite the low number of patients included in our study, SCA does not seem to be a risk factor for severe TB. What is Known: • Tuberculosis (TB) remains a global health problem particularly in developing countries, and Sickle cell anaemia (SCA) is currently one of the most common genetic diseases in the world that mainly affects African populations. • Very few data are available on TB in SCA patients. What is New: • The features of TB in children with SCA seem to be comparable to those expected in general population, with favourable outcomes in response to standard treatment. • Monitoring the dosage of anti-TB treatments could be of interest because of the possible impact of SCA on drug metabolism.

Immunogenicity and Safety of 10-valent Pneumococcal Nontypeable Haemophilus influenzae Protein D Conjugate Vaccine (PHiD-CV) Administered to Children With Sickle Cell Disease Between 8 Weeks and 2 Years of Age: A Phase III, Open, Controlled Study

BACKGROUND

Immunogenicity, safety and reactogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) were evaluated in children with sickle cell disease (SCD), who are at increased risk for infections.

METHODS

In this phase III, open-label, single-center, controlled study in Burkina Faso (NCT01175083), children with SCD (S) or without SCD (NS) were assigned to 6 groups (N = 300): children 8-11 weeks of age (<6 months; <6S and <6NS groups) received 3 primary doses and a booster dose of PHiD-CV coadministered with routine childhood vaccines; children 7-11 months of age (7-11S and 7-11NS groups) received 2 primary doses and a booster dose of PHiD-CV; children 12-23 months of age (12-23S and 12-23NS groups) received 2 catch-up doses of PHiD-CV. Pneumococcal antibody responses were measured using 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity. Responses to other antigens were measured by enzyme-linked immunosorbent assay. Adverse events were recorded.

RESULTS

One month postprimary vaccination, for each vaccine serotype ≥98% of infants in the <6S and <6NS groups had antibody concentrations ≥0.2 µg/mL, except for 6B (≥85%) and 23F (≥89%). Immune responses to PHiD-CV after age-appropriate vaccination in children <2 years did not appear influenced by SCD. All infants were seroprotected/seropositive for diphtheria, tetanus and Bordetella pertussis antigens postprimary and booster vaccination. Safety and reactogenicity profiles were similar in children with or without SCD.

CONCLUSIONS

PHiD-CV was immunogenic with an acceptable safety profile in children with and without SCD starting vaccination at 8 weeks to 23 months of age.

Antibiotics for treating community-acquired pneumonia in people with sickle cell disease

BACKGROUND

As a consequence of their condition, people with sickle cell disease are at high risk of developing an acute infection of the pulmonary parenchyma called community-acquired pneumonia. Many different bacteria can cause this infection and antibiotic treatment is generally needed to resolve it. There is no standardized approach to antibiotic therapy and treatment is likely to vary from country to country. Thus, there is a need to identify the efficacy and safety of different antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. This is an update of a previously published Cochrane Review.

OBJECTIVES

To determine the efficacy and safety of the antibiotic treatment approaches (monotherapy or combined) for people with sickle cell disease suffering from community-acquired pneumonia.

SEARCH METHODS

We searched The Group's Haemoglobinopathies Trials Register (01 September 2016), which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched LILACS (1982 to 01 September 2016), African Index Medicus (1982 to 20 October 2016) and WHO ICT Registry (20 October 2016).

SELECTION CRITERIA

We searched for published or unpublished randomized controlled trials.

DATA COLLECTION AND ANALYSIS

We intended to summarise data by standard Cochrane methodologies, but no eligible randomized controlled trials were identified.

MAIN RESULTS

We were unable to find any randomized controlled trials on antibiotic treatment approaches for community-acquired pneumonia in people with sickle cell disease.

AUTHORS' CONCLUSIONS

The updated review was unable to identify randomized controlled trials on efficacy and safety of the antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. Randomized controlled trials are needed to establish the optimum antibiotic treatment for this condition. The trials regarding this issue should be structured and reported according to the CONSORT statement for improving the quality of reporting of efficacy and improved reports of harms in clinical research. Triallists should consider including the following outcomes in new trials: number of days to become afebrile; mortality; onset of pain crisis or complications of sickle cell disease following community-acquired pneumonia; diagnosis; hospitalization (admission rate and length of hospital stay); respiratory failure rate; and number of participants receiving a blood transfusion.There are no trials included in the review and we have not identified any relevant trials up to September 2016. We therefore do not plan to update this review until new trials are published.

Antibody persistence after serogroup C meningococcal conjugate vaccine in children with sickle cell disease

BACKGROUND

A decline of protective antibody titers after MCC vaccine has been demonstrated in healthy children, this may be an issue of concern for risk groups. The aim of this study was to evaluate the persistence of bactericidal antibodies after MCC vaccine in sickle cell disease (SCD) patients. The type of vaccine used and booster response were also analyzed.

METHODS

SCD patients (n=141) previously immunized with MCC vaccines had blood drawn 2-8 years after the last priming dose. They were distributed according to age at primary immunization into groups: <2 years and 2-13 years and evaluated by years since vaccination (2-3, 4-5 and 6-8). Serum bactericidal antibodies with baby rabbit complement (rSBA) and serogroup C-specific IgG concentrations were measured. The correlate of protection was rSBA titer ⩾8. Subjects with rSBA <8 received a booster dose and antibody levels re-evaluated after 4-6 weeks.

RESULTS

For children primed under 2years of age rSBA titer ⩾8 was demonstrated in 53.3%, 21.7% and 35.0%, 2-3, 4-5, 6-8years, respectively, after vaccination, compared with 70.0%, 45.0% and 53.5%, respectively, for individuals primed at ages 2-13years. rSBA median titers and IgG median levels were higher in the older group. Six to eight years after vaccination the percentage of patients with rSBA titers ⩾8 was significantly higher in the group primed with MCC-TT (78.5%) compared with those primed with MCC-CRM197 [Menjugate® (33.3%) or Meningitec® (35.7%)] (p=0.033). After a booster, 98% achieved rSBA titer ⩾8.

CONCLUSION

Immunity to meningococcal serogroup C in SCD children declines rapidly after vaccination and is dependent on the age at priming. Booster doses are needed to maintain protection in SCD patients. Persistence of antibodies seems to be longer in individuals primed with MCC-TT vaccine comparing to those immunized with MCC-CRM197.

Preventing Infections in Sickle Cell Disease: The Unfinished Business

While encapsulated bacterial agents, particularly Streptococcus pneumoniae, are recognized as important microbes that are associated with serious illness in hosts with sickle cell disease (SCD), multiple pathogens are implicated in infectious manifestations of SCD. Variations in clinical practice have been an obstacle to the universal implementation of infection preventive management through active, targeted vaccination of these individuals and routine usage of antibiotic prophylaxis. Paradoxically, in low-income settings, there is evidence that SCD also increases the risk for several other infections that warrant additional infection preventive measures. The infection preventive care among patients with SCD in developed countries does not easily translate to the adoption of these recommendations globally, which must take into account the local epidemiology of infections, available vaccines and population-specific vaccine efficacy, environment, health care behaviors, and cultural beliefs, as these are all factors that play a complex role in the manifestation of SCD and the prevention of infectious disease morbidity.

Preventive Care Delivery to Young Children With Sickle Cell Disease

Preventive services can reduce the morbidity of sickle cell disease (SCD) in children but are delivered unreliably. We conducted a retrospective cohort study of children aged 2 to 5 years with SCD, evaluating each child for 14 months and expecting that he/she should receive ≥75% of days covered by antibiotic prophylaxis, ≥1 influenza immunization, and ≥1 transcranial Doppler ultrasound (TCD). We used logistic regression to quantify the relationship between ambulatory generalist and hematologist visits and preventive services delivery. Of 266 children meeting the inclusion criteria, 30% consistently filled prophylactic antibiotic prescriptions. Having ≥2 generalist, non-well child care visits or ≥2 hematologist visits was associated with more reliable antibiotic prophylaxis. Forty-one percent of children received ≥1 influenza immunizations. Children with ≥2 hematologist visits were most likely to be immunized (62% vs. 35% among children without a hematologist visit). Only 25% of children received ≥1 TCD. Children most likely to receive a TCD (42%) were those with ≥2 hematologist visits. One in 20 children received all 3 preventive services. Preventive services delivery to young children with SCD was inconsistent but associated with multiple visits to ambulatory providers. Better connecting children with SCD to hematologists and strengthening preventive care delivery by generalists are both essential.

Genomic analyses of pneumococci from children with sickle cell disease expose host-specific bacterial adaptations and deficits in current interventions

Sickle cell disease (SCD) patients are at high risk of contracting pneumococcal infection. To address this risk, they receive pneumococcal vaccines, and antibiotic prophylaxis and treatment. To assess the impact of SCD and these interventions on pneumococcal genetic architecture, we examined the genomes of more than 300 pneumococcal isolates from SCD patients over 20 years. Modern SCD strains retained invasive capacity but shifted away from the serotypes used in vaccines. These strains had specific genetic changes related to antibiotic resistance, capsule biosynthesis, metabolism, and metal transport. A murine SCD model coupled with Tn-seq mutagenesis identified 60 noncapsular pneumococcal genes under differential selective pressure in SCD, which correlated with aspects of SCD pathophysiology. Further, virulence determinants in the SCD context were distinct from the general population, and protective capacity of potential antigens was lost over time in SCD. This highlights the importance of understanding bacterial pathogenesis in the context of high-risk individuals.

Travelers with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is the most common genetic disease among persons with African ancestry. This article provides a background to SCD and reviews many important aspects of travel preparation in this population.

METHODS

The medical literature was searched for studies on travel-associated preparedness and complications in individuals with SCD. Topics researched included malaria, bacterial infections, vaccinations, dehydration, altitude, air travel, and travel preparedness.

RESULTS

There is very little published literature that specifically addresses the risks faced by travelers with SCD. Rates of medical complications during travel appear to be high. There is a body of literature that describes complications of SCD in indigenous populations, particularly within Africa. The generalizability of these data to a traveler is uncertain. Combining these sources of data and the broader medical literature, we address major travel-related questions that may face a provider preparing an individual with SCD for safe travel.

CONCLUSIONS

Travelers with SCD face considerable medical risks when traveling to developing tropical countries, including malaria, bacterial infections, hypovolemia, and sickle cell-associated vaso-occlusive crises. For individuals with SCD, frank counseling about the risks, vigilant preventative measures, and contingency planning for illness while abroad are necessary aspects of the pre-travel visit.

Fever in children with sickle cell disease: are all fevers equal?

BACKGROUND

Sepsis is the most common cause of mortality in sickle cell disease (SCD). Empiric antibiotic administration after obtaining blood cultures in febrile children with SCD has been a standard practice parameter.

OBJECTIVE

Our primary objective was to calculate the rate of bacteremia in febrile pediatric patients with SCD. Our secondary objective was to establish whether vital signs or diagnostics predict bacteremia in these patients.

METHODS

We conducted a retrospective chart review of patients with SCD who presented to an urban pediatric emergency department in Newark, NJ between January 1, 2001 and June 30, 2011 with the chief complaint of fever. Patients between the ages of 0 and 20 years with SCD who presented with the chief complaint of fever and who had a blood culture performed were included. Descriptive data, visit-specific data, and diagnostic data were collected.

RESULTS

Charts of 307 patients were included. Six patients had a positive blood culture, one of which was considered a true pathogen (Streptococcus pneumoniae) (0.33%; 95% confidence interval 0.06%-1.86%). There was no statistical significance between the means of visit-specific and diagnostic data of patients with positive blood cultures and those with negative blood cultures.

CONCLUSIONS

The incidence of bacteremia in febrile children with SCD presenting to the emergency department is low. Close follow-up within 24 hours and delayed antibiotic administration can be a plausible alternative treatment option in this population.

Systematic review of the effect of pneumococcal conjugate vaccine dosing schedules on vaccine-type invasive pneumococcal disease among young children

BACKGROUND

Pneumococcal conjugate vaccines (PCV) are being implemented globally using a variety of different schedules. The optimal schedule to maximize protection of vaccinated children against vaccine-type invasive pneumococcal disease (VT-IPD) is not known.

METHODS

To assess the relative benefit of various PCV dosing schedules, we conducted a systematic review of studies published in English from 1994 to 2010 (supplemented post hoc with studies from 2011) on PCV effectiveness against VT-IPD among children targeted to receive vaccine. Data on 2-dose and 3-dose primary series, both with and without a booster ("2+0," "2+1," "3+0" and "3+1"), were included. For observational studies using surveillance data or case counts, we calculated percentage reduction in VT-IPD before and after PCV introduction.

RESULTS

Of 4 randomized controlled trials and 31 observational studies reporting VT-IPD among young children, none evaluated a 2+0 complete series, 7 (19%) evaluated 2+1, 4 (11%) 3+0 and 27 (75%) 3+1. Most (86%) studies were from North America or Europe. Only 1 study (observational) directly compared 2 schedules (3+0 vs. 3+1); results supported the use of a booster dose. In clinical trials, vaccine efficacy ranged from 65% to 71% with 3+0 and 83% to 94% with 3+1. Surveillance data and case counts demonstrate reductions in VT-IPD of up to 100% with 2+1 (6 studies) or 3+1 (17 studies) schedules and up to 90% with 3+0 (2 studies). Reductions were observed as early as 1 year after PCV introduction.

CONCLUSIONS

These data support the use of 2+1, 3+0 and 3+1 schedules, although most data of PCV impact on VT-IPD among young children are from high-income countries using 3+1. Differences between schedules for impact on VT-IPD are difficult to discern based on available data.

Invasive pneumococcal disease among children with and without sickle cell disease in the United States, 1998 to 2009

BACKGROUND

Children with sickle cell disease (SCD) are at increased risk of illness and death from invasive pneumococcal disease (IPD). The introduction in 2000 of the 7-valent pneumococcal conjugate vaccine and penicillin prophylaxis for children with SCD has greatly reduced the incidence of IPD in this population. However, a recent report suggested an increase in cases of IPD in children with SCD.

METHODS

Using data from Active Bacterial Core surveillance, we analyzed trends in hospitalizations, mortality and serotype among children with SCD compared with other children. We used neonatal screening data to estimate SCD population denominators for each Active Bacterial Core surveillance site.

RESULTS

From 1998 to 2009, 3069 cases of IPD occurred among African-American children less than 18 years of age in the Active Bacterial Core surveillance catchment area. Of these, 127 (4.1%) had SCD identified by medical chart review and 185 (6.0%) had 1 or more IPD risk factors, excluding SCD. Rates of IPD among children with SCD declined by 53% (1118 vs. 530 per 100,000) whereas the overall rates among African-American children declined by 74% (54 to 14 per 100,000). For all time periods, children with SCD and IPD were more likely to be hospitalized (84%-92% vs. 31%-56%) and more likely to die (6%-17% vs. 1%-2%) than children with no risk factors.

CONCLUSIONS

Although the rate of IPD in children with SCD has dropped dramatically since 7-valent pneumococcal conjugate vaccine introduction, the rate of IPD in children with SCD remains higher than that of the general population of African-American children, pointing to the need for more effective prevention efforts to prevent IPD in children with SCD.

Epidemiology of Infant Salmonellosis in the United States, 1996-2008: A Foodborne Diseases Active Surveillance Network Study

BACKGROUND

Infants have increased risk for salmonellosis; but epidemiologic information is limited.

METHODS

We reviewed Foodborne Diseases Active Surveillance Network reports of laboratory-confirmed non-Typhi Salmonella infections in infants from 1996-2008. We calculated incidence, estimated relative risks, and assessed trends over the duration of the study period, using the first 3 years as reference.

RESULTS

Average annual incidence of salmonellosis per 100 000 infants was 177.8 (95% confidence interval [CI], 152.7-202.8) in blacks, 129.7 (95% CI, 94.8-164.7) in Asians, and 81.1 (95% CI, 70.2-92.0) in whites. Our analysis of ethnicity independent of race showed salmonellosis incidence of 86.7 (95% CI, 74.6-98.9) in Hispanics and 69.4 (95% CI, 54.8-84.1) in non-Hispanics. Salmonellosis was invasive more often in blacks (9.4%) and Asians (6.4%) than whites (3.6%, P <.001 and P = .01, respectively). Asian infants with salmonellosis were older (median, 31 weeks [range, 0-52]) than black (24 weeks [range, 0-52], P < .001) or white infants (23 weeks [range, 0-52], P < .001). Incidence of all salmonellosis remained stable for whites from 1996-1998 through 2008, but blacks had a sustained decrease, with relative risk of 0.48 (95% CI, .37-.63) in 2008 compared with 1996-1998. However, 2008 incidence remained highest among blacks (141.0 of 100 000 vs 113.5 of 100 000 among whites and 109.9 of 100 000 among Asians).

CONCLUSION

Black infants had a greater risk of salmonellosis and invasive disease than other racial groups, and despite the greatest decrease in incidence over the study period, they continued to have the highest incidence of salmonellosis. The decrease in salmonellosis in black infants suggests that future improvements may be possible for other population subgroups.

Increased reticulocytosis during infancy is associated with increased hospitalizations in sickle cell anemia patients during the first three years of life

Objective

Among older children with sickle cell anemia, leukocyte counts, hemoglobin, and reticulocytosis have previously been suggested as disease severity markers. Here we explored whether these blood parameters may be useful to predict early childhood disease severity when tested in early infancy, defined as postnatal ages 60–180 days.

Study Design

Data from fifty-nine subjects who were followed at Children’s National Medical Center’s Sickle Cell Program for at least three years was retrospectively analyzed. Comparisons were made between white blood cell counts, hemoglobin and reticulocyte levels measured at ages 60–180 days and the clinical course of sickle cell anemia during infancy and childhood.

Results

A majority of subjects had demonstrable anemia with increased reticulocytosis. Only increased absolute reticulocyte levels during early infancy were associated with a significant increase in hospitalization during the first three years of life. Higher absolute reticulocyte counts were also associated with a markedly shorter time to first hospitalizations and a four-fold higher cumulative frequency of clinical manifestations over the first three years of life. No significant increase in white blood cell counts was identified among the infant subjects.

Conclusions

These data suggest that during early infancy, increased reticulocytosis among asymptomatic SCA subjects is associated with increased severity of disease in childhood.

Antibiotics for treating community acquired pneumonia in people with sickle cell disease

BACKGROUND

As a consequence of their condition, people with sickle cell disease are at high risk of developing an acute infection of the pulmonary parenchyma called community-acquired pneumonia. Many different bacteria can cause this infection and antibiotic treatment is generally needed to resolve it. There is no standardized approach to antibiotic therapy and treatment is likely to vary from country to country. Thus, there is a need to identify the efficacy and safety of different antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia.

OBJECTIVES

To determine the efficacy and safety of the antibiotic treatment approaches (monotherapy or combined) for people with sickle cell disease suffering from community-acquired pneumonia.

SEARCH METHODS

We searched The Group's Haemoglobinopathies Trials Register (25 May 2012), which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched LILACS (1982 to 27 April 2012), African Index Medicus (1982 to 27 April 2012) and WHO ICT Registry (27 April 2012).

SELECTION CRITERIA

We searched for published or unpublished randomized controlled trials.

DATA COLLECTION AND ANALYSIS

We intended to summarise data by standard Cochrane Collaboration methodologies, but no eligible randomized controlled trials were identified.

MAIN RESULTS

We were unable to find any randomized controlled trials on antibiotic treatment approaches for community-acquired pneumonia in people with sickle cell disease.

AUTHORS' CONCLUSIONS

The updated review was unable to identify randomized controlled trials on efficacy and safety of the antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. Randomized controlled trials are needed to establish the optimum antibiotic treatment for this condition. The trials regarding this issue should be structured and reported according to the CONSORT statement for improving the quality of reporting of efficacy and improved reports of harms in clinical research. Triallists should consider including the following outcomes in new trials: number of days to become afebrile; mortality; onset of pain crisis or complications of SCD following CAP; diagnosis; hospitalisation (admission rate and length of hospital stay); respiratory failure rate; and number of participants receiving a blood transfusion.There are no trials included in the review and we have not identified any relevant trials up to May 2012. We therefore do not plan to update this review until new trials are published.

Splenic morphological changes are accompanied by altered baseline immunity in a mouse model of sickle-cell disease

Although functional asplenia from infarctions may be a major contributor to increased infectious mortality in sickle-cell disease (SCD), this relationship has not been fully defined. We used the transgenic Berkeley SCD mouse to define blood and splenic immunophenotypic differences in this model compared with C57BL/6 and hemizygous controls. In the serum of SCD mice, we found increased IgG2a and suppressed IgM, IgG2b, and IgA levels. Serum IL-6 levels in SCD mice were elevated, whereas IL-1α, CXCL10, and CCL5 levels were decreased. The blood of SCD mice had higher white blood cell counts, with an increased percentage of lymphocytes and decreases in other leukocytes. Immunophenotyping of lymphocytes revealed higher percentages of CD8(+) and T-regulatory cells and lower percentages of B cells. SCD mouse spleens exhibited histological disorganization, with reduction of defined lymphoid follicles and expansion of red pulp, a greater than fourfold increase in splenic mononuclear cells, marked expansion of the nucleated red blood cell fraction, and B-cell and CD8(+) T-cell lymphopenia. Within the splenic B-cell population, there was a significant decrease in B-1a B cells, with a corresponding decrease in IgA secreting plasma cells in the gut. Confocal microscopy of spleens demonstrated complete disruption of the normal lymphofollicular structure in the white pulp of SCD mice without distinct B, T, and marginal zones. Our findings suggest that altered SCD splenic morphological characteristics result in an impaired systemic immune response.

Nasopharyngeal carriage rate of Streptococcus pneumoniae in Ugandan children with sickle cell disease

Background

Nasopharyngeal carriage of Streptococcus pneumoniae is a determinant for invasive pneumococcal disease, which often complicates homozygous sickle cell disease. Here, we determined the nasopharyngeal carriage rate of S. pneumoniae in Ugandan children with homozygous sickle cell disease, who attended the outpatient Sickle Cell Clinic at Mulago National Referral hospital in Kampala, Uganda.

Results

S. pneumoniae occurred in 27 of the 81 children with homozygous sickle cell disease (giving a carriage rate of 33%, 27/81). Twenty three children were previously hospitalized of whom S. pneumoniae occurred in only two (9%, 2/23), while among the 58 who were not previously hospitalized it occurred in 25 (43%, 25/58, χ² = 8.8, p = 0.003), meaning there is an association between high carriage rate and no hospitalization. Two children previously immunized with the pneumococcal conjugate vaccine did not carry the organism. Prior antimicrobial usage was reported in 53 children (65%, 53/81). There was high resistance of pneumococci to penicillin (100%, 27/27) and trimethoprime-sulfamethoxazole (97%, 26/27), but low resistance to other antimicrobials. Of the 70 children without sickle cell disease, S. pneumoniae occurred in 38 (54%, 38/70) of whom 43 were males and 27 females (53% males, 23/43, and 56% females, 15/27).

Conclusion

Nasopharyngeal carriage of penicillin resistant pneumococci in Ugandan children with homozygous sickle cell disease is high. While nasopharyngeal carriage of S. pneumoniae is a determinant for invasive pneumococcal disease, pneumococcal bacteremia is reportedly low in Ugandan children with sickle cell disease. Studies on the contribution of high carriage rates to invasive pneumococcal disease in these children will be helpful. This is the first report on pneumococcal carriage rate in Ugandan children with sickle cell disease.