Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Clinical and Hypoxemic Childhood Pneumonia over Three Years in Central Malawi: An Observational Study.

BACKGROUND: The pneumococcal conjugate vaccine's (PCV) impact on childhood pneumonia during programmatic conditions in Africa is poorly understood. Following PCV13 introduction in Malawi in November 2011, we evaluated the case burden and rates of childhood pneumonia. METHODS AND FINDINGS: Between January 1, 2012-June 30, 2014 we conducted active pneumonia surveillance in children <5 years at seven hospitals, 18 health centres, and with 38 community health workers in two districts, central Malawi. Eligible children had clinical pneumonia per Malawi guidelines, defined as fast breathing only, chest indrawing +/- fast breathing, or, ≥1 clinical danger sign. Since pulse oximetry was not in the Malawi guidelines, oxygenation <90% defined hypoxemic pneumonia, a distinct category from clinical pneumonia. We quantified the pneumonia case burden and rates in two ways. We compared the period immediately following vaccine introduction (early) to the period with >75% three-dose PCV13 coverage (post). We also used multivariable time-series regression, adjusting for autocorrelation and exploring seasonal variation and alternative model specifications in sensitivity analyses. The early versus post analysis showed an increase in cases and rates of total, fast breathing, and indrawing pneumonia and a decrease in danger sign and hypoxemic pneumonia, and pneumonia mortality. At 76% three-dose PCV13 coverage, versus 0%, the time-series model showed a non-significant increase in total cases (+47%, 95% CI: -13%, +149%, p = 0.154); fast breathing cases increased 135% (+39%, +297%, p = 0.001), however, hypoxemia fell 47% (-5%, -70%, p = 0.031) and hospital deaths decreased 36% (-1%, -58%, p = 0.047) in children <5 years. We observed a shift towards disease without danger signs, as the proportion of cases with danger signs decreased by 65% (-46%, -77%, p<0.0001). These results were generally robust to plausible alternative model specifications. CONCLUSIONS: Thirty months after PCV13 introduction in Malawi, the health system burden and rates of the severest forms of childhood pneumonia, including hypoxemia and death, have markedly decreased.

Peripheral blood RNA gene expression in children with pneumococcal meningitis: a prospective case-control study.

INTRODUCTION: Invasive pneumococcal disease (IPD), caused by Streptococcus pneumoniae, is a leading cause of pneumonia, meningitis and septicaemia worldwide, with increased morbidity and mortality in HIV-infected children. OBJECTIVES: We aimed to compare peripheral blood expression profiles between HIV-infected and uninfected children with pneumococcal meningitis and controls, and between survivors and non-survivors, in order to provide insight into the host inflammatory response leading to poorer outcomes. DESIGN AND SETTING: Prospective case-control observational study in a tertiary hospital in Malawi. PARTICIPANTS: Children aged 2 months to 16 years with pneumococcal meningitis or pneumonia. METHODS: We used the human genome HGU133A Affymetrix array to explore differences in gene expression between cases with pneumococcal meningitis (n=12) and controls, and between HIV-infected and uninfected cases, and validated gene expression profiles for 34 genes using real-time quantitative PCR (RT-qPCR) in an independent set of cases with IPD (n=229) and controls (n=13). Pathway analysis was used to explore genes differentially expressed. RESULTS: Irrespective of underlying HIV infection, cases showed significant upregulation compared with controls of the following: S100 calcium-binding protein A12 (S100A12); vanin-1 (VNN1); arginase, liver (ARG1); matrix metallopeptidase 9 (MMP9); annexin A3 (ANXA3); interleukin 1 receptor, type II (IL1R2); CD177 molecule (CD177); endocytic adaptor protein (NUMB) and S100 calcium-binding protein A9 (S100A9), cytoskeleton-associated protein 4 (CKAP4); and glycogenin 1 (GYG1). RT-qPCR confirmed differential expression in keeping with microarray results. There was no differential gene expression in HIV-infected compared with HIV-uninfected cases, but there was significant upregulation of folate receptor 3 (FOLR3), S100A12 in survivors compared with non-survivors. CONCLUSION: Children with IPD demonstrated increased expression in genes regulating immune activation, oxidative stress, leucocyte adhesion and migration, arginine metabolism, and glucocorticoid receptor signalling.

Pulse oximetry for children with pneumonia treated as outpatients in rural Malawi.

OBJECTIVE: To investigate implementation of outpatient pulse oximetry among children with pneumonia, in Malawi. METHODS: In 2011, 72 health-care providers at 18 rural health centres and 38 community health workers received training in the use of pulse oximetry to measure haemoglobin oxygen saturations. Data collected, between 1 January 2012 and 30 June 2014 by the trained individuals, on children aged 2-59 months with clinically diagnosed pneumonia were analysed. FINDINGS: Of the 14 092 children included in the analysis, 13 266 (94.1%) were successfully checked by oximetry. Among the children with chest indrawing and/or danger signs, those with a measured oxygen saturation below 90% were more than twice as likely to have been referred as those with higher saturations (84.3% [385/457] vs 41.5% [871/2099]; P < 0.001). The availability of oximetry appeared to have increased the referral rate for severely hypoxaemic children without chest indrawing or danger signs from 0% to 27.2% (P < 0.001). In the absence of oximetry, if the relevant World Health Organization (WHO) guidelines published in 2014 had been applied, 390/568 (68.7%) severely hypoxaemic children at study health centres and 52/84 (61.9%) severely hypoxaemic children seen by community health workers would have been considered ineligible for referral. CONCLUSION: Implementation of pulse oximetry by our trainees substantially increased the referrals of Malawian children with severe hypoxaemic pneumonia. When data from oximetry were excluded, retrospective application of the guidelines published by WHO in 2014 failed to identify a considerable proportion of severely hypoxaemic children eligible only via oximetry.

Non-treatment of children with community health worker-diagnosed fast-breathing pneumonia in rural Malawi: exploratory subanalysis of a prospective cohort study.

BACKGROUND: Despite recent progress, pneumonia remains the largest infectious killer of children globally. This paper describes outcomes of not treating community-diagnosed fast-breathing pneumonia on patient recovery. METHODS: We conducted an exploratory subanalysis of an observational prospective cohort study in Malawi. We recruited children (2-59 months) diagnosed by community health workers with fast-breathing pneumonia using WHO integrated community case management (iCCM) guidelines. Children were followed at days 5 and 14 with a clinical assessment of recovery. We conducted bivariate and multivariable logistic regression for the association between treatment of fast-breathing pneumonia and recovery, adjusting for potential confounders. RESULTS: We followed up 847 children, of whom 78 (9%) had not been given antibiotics (non-treatment). Non-treatment cases had higher baseline rates of diarrhoea, non-severe hypoxaemia and fever. Non-recovery (persistence or worsening of symptoms) was 13% and 23% at day 5 in those who did receive and those who did not receive co-trimoxazole. Non-recovery, when defined as worsening of symptoms only, at day 5 was 7% in treatment and 10% in non-treatment cases. For both definitions, combined co-trimoxazole and lumefantrine-artemether (LA) treatment trended towards protection (adjusted OR (aOR) 0.28; 95% CI 0.12 to 0.68/aOR 0.29; 95% CI 0.08 to 1.01). CONCLUSION: We found that children who did not receive co-trimoxazole treatment had worse clinical outcomes; malaria co-diagnosis and treatment also play a significant role in non-recovery. Further research into non-treatment of fast-breathing pneumonia, using a pragmatic approach with consideration for malaria co-diagnosis and HIV status is needed to guide refinement of community treatment algorithms in this region.

Non-adherence to community oral-antibiotic treatment in children with fast-breathing pneumonia in Malawi- secondary analysis of a prospective cohort study.

BACKGROUND: Despite significant progress, pneumonia is still the leading cause of infectious deaths in children under five years of age. Poor adherence to antibiotics has been associated with treatment failure in World Health Organisation (WHO) defined clinical pneumonia; therefore, improving adherence could improve outcomes in children with fast-breathing pneumonia. We examined clinical factors that may affect adherence to oral antibiotics in children in the community setting in Malawi. METHODS: We conducted a sub-analysis of a prospective cohort of children aged 2-59 months diagnosed by community health workers (CHW) in rural Malawi with WHO fast-breathing pneumonia. Clinical factors identified during CHW diagnosis were investigated using multivariate logistic regression for association with non-adherence, including concurrent diagnoses and treatments. Adherence was measured at both 80% and 100% completion of prescribed oral antibiotics. RESULTS: Eight hundred thirty-four children were included in our analysis, of which 9.5% and 20.0% were non-adherent at 80% and 100% of treatment completion, respectively. A concurrent infectious diagnosis (OR: 1.76, 95% CI: 0.84-2.96/OR: 1.81, 95% CI: 1.21-2.71) and an illness duration of >24 h prior to diagnosis (OR: 2.14, 95% CI: 1.27-3.60/OR: 1.88, 95% CI: 1.29-2.73) had higher odds of non-adherence when measured at both 80% and 100%. Older age was associated with lower odds of non-adherence when measured at 80% (OR: 0.41, 95% CI: 0.21-0.78). CONCLUSION: Non-adherence to oral antibiotics was not uncommon in this rural sub-Saharan African setting. As multiple diagnoses by the CHW and longer illness were important factors, this provides an opportunity for further investigation into targeted interventions and refinement of referral guidelines at the community level. Further research into the behavioural drivers of non-adherence within this setting is needed.

Can We Predict Oral Antibiotic Treatment Failure in Children with Fast-Breathing Pneumonia Managed at the Community Level? A Prospective Cohort Study in Malawi.

BACKGROUND: Pneumonia is the leading cause of infectious death amongst children globally, with the highest burden in Africa. Early identification of children at risk of treatment failure in the community and prompt referral could lower mortality. A number of clinical markers have been independently associated with oral antibiotic failure in childhood pneumonia. This study aimed to develop a prognostic model for fast-breathing pneumonia treatment failure in sub-Saharan Africa. METHOD: We prospectively followed a cohort of children (2-59 months), diagnosed by community health workers with fast-breathing pneumonia using World Health Organisation (WHO) integrated community case management guidelines. Cases were followed at days 5 and 14 by study data collectors, who assessed a range of pre-determined clinical features for treatment outcome. We built the prognostic model using eight pre-defined parameters, using multivariable logistic regression, validated through bootstrapping. RESULTS: We assessed 1,542 cases of which 769 were included (32% ineligible; 19% defaulted). The treatment failure rate was 15% at day 5 and relapse was 4% at day 14. Concurrent malaria diagnosis (OR: 1.62; 95% CI: 1.06, 2.47) and moderate malnutrition (OR: 1.88; 95% CI: 1.09, 3.26) were associated with treatment failure. The model demonstrated poor calibration and discrimination (c-statistic: 0.56). CONCLUSION: This study suggests that it may be difficult to create a pragmatic community-level prognostic child pneumonia tool based solely on clinical markers and pulse oximetry in an HIV and malaria endemic setting. Further work is needed to identify more accurate and reliable referral algorithms that remain feasible for use by community health workers.

Glycerol and acetaminophen as adjuvant therapy did not affect the outcome of bacterial meningitis in Malawian children.

We investigated the benefit of 2 candidate adjunctive therapies in bacterial meningitis: glycerol, which has shown promise in earlier studies, and acetaminophen, which is reportedly beneficial in adult septicemia. In a hospital in Blantyre, Malawi, we enrolled 360 children aged ≥ 2 months with proven bacterial meningitis (36% HIV infected) in a double-blind, randomized, placebo-controlled trial of glycerol and acetaminophen in a 2 × 2 factorial design. Of 4 groups, first group received oral glycerol, second received rectal acetaminophen, third received both therapies and the fourth received placebos only. Adjuvant therapies were given for the first 48 hours of antibiotic therapy. Endpoints were mortality and neurological sequelae. Baseline findings were similar across all groups, except that many children had prior antibiotics in the acetaminophen group and many were anemic in the acetaminophen and glycerol group. Outcomes were similar for all groups. We found no benefit from oral glycerol or rectal acetaminophen in, mostly pneumococcal, meningitis in Malawian children.

Risk factors for death and severe sequelae in Malawian children with bacterial meningitis, 1997-2010.

BACKGROUND: Acute bacterial meningitis (ABM) causes significant death and disability in children worldwide, with HIV recognized as an established risk factor for infection and negative outcomes. However, additional major risk factors for death and disability in pediatric ABM remain unclear. METHODS: We conducted a retrospective analysis of case data from 3 departmental studies of ABM involving 1784 children <15 years old who attended Queen Elizabeth Central Hospital in Blantyre, Malawi during 1997 to 2010. Univariate and multivariate logistic regression models were used to estimate the effects of HIV seropositivity, impaired consciousness and causative organism on death and severe sequelae. RESULTS: Impaired consciousness or coma at the time of admission was strongly associated with death (coma: odds ratio [OR] = 14.4, 95% confidence interval [CI]: 9.42, 22.1) and severe sequelae (Coma: OR = 3.27, 95% CI: 2.02, 5.29) in multivariate logistic regression models. HIV seropositivity was significantly associated with increased odds of death (OR = 1.65, 95% CI: 1.20, 2.26) but not with developing severe sequelae (OR = 0.88, 95% CI: 0.56, 1.38). After adjustment, infection with Salmonella spp. was associated with increased odds of death (OR = 2.11, 95% CI: 1.06, 4.08) and pneumococcal meningitis was associated with increased odds of severe sequelae (OR = 1.84, 95% CI: 1.03, 3.29). CONCLUSIONS: Impaired consciousness and HIV infection increased the odds of death from ABM in Malawian children. Use of pneumococcal conjugate vaccine could greatly reduce the burden of ABM in Malawi.

Novel biomarker combination improves the diagnosis of serious bacterial infections in Malawian children.

BACKGROUND: High throughput technologies offer insight into disease processes and heightens opportunities for improved diagnostics. Using transcriptomic analyses, we aimed to discover and to evaluate the clinical validity of a combination of reliable and functionally important biomarkers of serious bacterial infection (SBI). METHODS: We identified three previously reported biomarkers of infection (neutrophil gelatinase-associated lipocalin (NGAL), granulysin and resistin) and measured gene expression using quantitative real-time PCR. Protein products related to the three transcripts were measured by immunoassays. RESULTS: Relative gene expression values of NGAL and resistin were significantly increased, and expression of granulysin significantly decreased in cases compared to controls. Plasma concentrations of NGAL and resistin were significantly increased in children with confirmed SBI compared to children with no detectable bacterial infection (NBI), and to controls (287 versus 128 versus 62 ng/ml and 195 versus 90 versus 18 ng/ml, respectively, p < 0.05). Plasma protein concentrations of NGAL and resistin were significantly increased in non-survivors compared to survivors (306 versus 211 and 214 versus 150 ng/ml, p = 0.02). The respective areas under the curve (AUC) for NGAL, resistin and procalcitonin in predicting SBI were 0.79, 0.80 and 0.86, whilst a combination of NGAL, resistin and procalcitonin achieved an AUC of 0.90. CONCLUSIONS: We have demonstrated a unique combination of diagnostic biomarkers of SBI using transcriptomics, and demonstrated translational concordance with the corresponding protein. The addition of NGAL and resistin protein measurement to procalcitonin significantly improved the diagnosis of SBI.

Lactate as a predictor of mortality in Malawian children with WHO-defined pneumonia.

OBJECTIVES: To determine whether blood lactate measured at the time of presentation to hospital predicted outcome in children with pneumonia in Malawi, and to understand the factors associated with high blood lactate concentrations in pneumonia. DESIGN: Analysis of data from a prospective study of children presenting to Queen Elizabeth Central Hospital, Blantyre, with WHO-defined severe or very severe pneumonia. RESULTS: Among 233 children with pneumonia, the median serum lactate concentration was 2.7 mmol/l (IQR 1.8-4.4 mmol/l). 77 children (33%) had a lactate concentration of 2.1-4.0 mmol/l, and 72 children (31%) had a lactate concentration >4.0 mmol/l. 92% of children who died (23/25) had lactate >2.0 mmol/l at the time of admission to hospital. There were 10 deaths (13%) among 77 children who had a serum lactate concentration of 2.1-4.0 mmol/l; and 13 deaths (18%) in the 72 children who had lactate >4.0 mmol/l. The relative risk of death if the lactate level was above 2 mmol/l was 7.48 (1.72-32.6); sensitivity 0.92, specificity 0.39, positive predictive value 0.15, negative predictive value 0.98. Multivariable analysis showed that hypoxaemia, hyperlactataemia and age ≤12 months were independent risk factors for death from pneumonia. CONCLUSIONS: Used in conjunction with clinical risk factors and pulse oximetry for measuring oxygen saturation, lactate could play an important role in identifying the sickest patients with pneumonia in developing countries.

PCR improves diagnostic yield from lung aspiration in Malawian children with radiologically confirmed pneumonia.

BACKGROUND: Accurate data on childhood pneumonia aetiology are essential especially from regions where mortality is high, in order to inform case-management guidelines and the potential of prevention strategies such as bacterial conjugate vaccines. Yield from blood culture is low, but lung aspirate culture provides a higher diagnostic yield. We aimed to determine if diagnostic yield could be increased further by polymerase chain reaction (PCR) detection of bacteria (Streptococcus pneumoniae and Haemophilus influenzae b) and viruses in lung aspirate fluid. METHODS: A total of 95 children with radiological focal, lobar or segmental consolidation had lung aspirate performed and sent for bacterial culture and for PCR for detection of bacteria, viruses and Pneumocystis jirovecii. In children with a pneumococcal aetiology, pneumococcal bacterial loads were calculated in blood and lung aspirate fluid. RESULTS: Blood culture identified a bacterial pathogen in only 8 patients (8%). With the addition of PCR on lung aspirate samples, causative pathogens (bacterial, viral, pneumocystis) were identified singly or as co-infections in 59 children (62%). The commonest bacterial organism was S.pneumoniae (41%), followed by H. influenzae b (6%), and the commonest virus identified was adenovirus (16%), followed by human bocavirus (HBoV) (4%), either as single or co-infection. CONCLUSIONS: In a select group of African children, lung aspirate PCR significantly improves diagnostic yield. Our study confirms a major role of S.pneumoniae and viruses in the aetiology of childhood pneumonia in Africa.

The IL1RN promoter rs4251961 correlates with IL-1 receptor antagonist concentrations in human infection and is differentially regulated by GATA-1.

IL-1R antagonist (IL-1Ra) is required for adequate host defense in invasive pneumococcal disease (IPD). The minor allele of an IL1RN gene (C/T) promoter polymorphism (rs4251961) has been shown to be associated with decreased IL-1Ra production in healthy adults. We genotyped 299 children with IPD, and examined 19 IL1RN haplotype-tagging single-nucleotide polymorphisms. Human embryonic kidney HEK293(T) cells were transfected with the promoter reporter plasmid pGL3p containing either allelic variant C (pGL3pCC) or T (pGL3pTT) with or without cotransfection with an expression construct overexpressing the globin transcription factor GATA-1. Plasma IL-1Ra concentrations were significantly higher in nonsurvivors compared with survivors (p < 0.0005), and the C allele of rs4251961 was associated with a significant increase in plasma IL-1Ra concentrations (p = 0.01) during the acute illness of IPD. These findings were validated in a cohort of 276 treatment-naive HIV-infected adults, with borderline significance (p = 0.058). Functional analyses demonstrated that the activity of the promoter constructs containing the T allele increased ~6-fold as compared with basal activity, and that containing the C allele by ~9-fold (p < 0.001) in the presence of GATA-1. Our findings suggest that the IL-1Ra single-nucleotide polymorphism rs4251961 plays a key role in the pathophysiology of IPD and in other human infections.

Impact of human immunodeficiency virus infection on the etiology and outcome of severe pneumonia in Malawian children.

BACKGROUND: HIV infection is a major risk factor for death in childhood pneumonia in HIV-endemic regions. Improved case management and preventive strategies require better understanding of the impact of HIV on causes, clinical presentation, and outcome. METHODS: A prospective, clinical descriptive study of Malawian infants and children with severe pneumonia included blood culture and nasopharyngeal aspiration for diagnosis of pneumocystis pneumonia (PcP). A select group with consolidation on chest radiograph, and without severe hypoxia or hyperinflation, also had lung aspirate taken for culture and identification of bacterial deoxyribonucleic acid by real-time polymerase chain reaction (PCR). RESULTS: There were 327 study patients with a median age of 11 months (range, 2 months-14 years). HIV prevalence was 51%. There were 58 cases of confirmed bacterial pneumonia, of which the most common bacterial isolates were Streptococcus pneumoniae and Salmonella typhimurium. Of the 54 lung aspirates, only 2 were positive on culture but 27 were positive for bacterial deoxyribonucleic acid by PCR. PcP was confirmed in 16 patients, and was associated with young age, severe hypoxia, HIV infection, and a very poor outcome. The overall case-fatality rate was 10% despite presumptive therapy for PcP and routine broad-spectrum antibiotic treatment appropriate for local antimicrobial susceptibility data. Most of the deaths occurred in infants of 2 to 6 months of age and PcP was associated with 57% of these deaths. CONCLUSIONS: PcP is a major barrier in reducing the case-fatality rate of severe pneumonia in infants of HIV-endemic communities. The use of PCR on lung aspirate specimens greatly increased the diagnostic yield.

The role of angiogenic factors in predicting clinical outcome in severe bacterial infection in Malawian children.

INTRODUCTION: Severe sepsis is a disease of the microcirculation, with endothelial dysfunction playing a key role in its pathogenesis and subsequent associated mortality. Angiogenesis in damaged small vessels may ameliorate this dysfunction. The aim of the study was to determine whether the angiogenic factors (vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and angiopoietin-1 (Ang-1) and -2 (Ang-2)) are mortality indicators in Malawian children with severe bacterial infection. METHODS: In 293 children with severe bacterial infection, plasma VEGF, PDGF, FGF, and Ang-1 and Ang-2 were measured on admission; in 50 of the children with meningitis, VEGF, PDGF, and FGF were also measured in the CSF. Healthy controls comprised children from some of the villages of the index cases. Univariable and multivariable logistic regression analyses were performed to develop a prognostic model. RESULTS: The median age was 2.4 years, and the IQR, 0.7 to 6.0 years. There were 211 children with bacterial meningitis (72%) and 82 (28%) with pneumonia, and 154 (53%) children were HIV infected. Mean VEGF, PDGF, and FGF concentrations were higher in survivors than in nonsurvivors, but only PDGF remained significantly increased in multivariate analysis (P = 0.007). Mean Ang-1 was significantly increased, and Ang-2 was significantly decreased in survivors compared with nonsurvivors (6,000 versus 3,900 pg/ml, P = 0.03; and 7,700 versus 11,900 pg/ml, P = 0.02, respectively). With a logistic regression model and controlling for confounding factors, only female sex (OR, 3.95; 95% CI, 1.33 to 11.76) and low Ang-1 (OR, 0.23; 95% CI, 0.08 to 0.69) were significantly associated with mortality. In children with bacterial meningitis, mean CSF VEGF, PDGF, and FGF concentrations were higher than paired plasma concentrations, and mean CSF, VEGF, and FGF concentrations were higher in nonsurvivors than in survivors (P = 0.02 and 0.001, respectively). CONCLUSIONS: Lower plasma VEGF, PDGF, FGF, and Ang-1 concentrations and higher Ang-2 concentrations are associated with an unfavorable outcome in children with severe bacterial infection. These angiogenic factors may be important in the endothelial dysregulation seen in severe bacterial infection, and they could be used as biomarkers for the early identification of patients at risk of a poor outcome.

The diagnostic and prognostic accuracy of five markers of serious bacterial infection in Malawian children with signs of severe infection.

BACKGROUND: Early recognition and prompt and appropriate antibiotic treatment can significantly reduce mortality from serious bacterial infections (SBI). The aim of this study was to evaluate the utility of five markers of infection: C-reactive protein (CRP), procalcitonin (PCT), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), CD163 and high mobility group box-1 (HMGB1), as markers of SBI in severely ill Malawian children. METHODOLOGY AND PRINCIPAL FINDINGS: Children presenting with a signs of meningitis (n = 282) or pneumonia (n = 95), were prospectively recruited. Plasma samples were taken on admission for CRP, PCT, sTREM-1 CD163 and HMGB1 and the performance characteristics of each test to diagnose SBI and to predict mortality were determined. Of 377 children, 279 (74%) had SBI and 83 (22%) died. Plasma CRP, PCT, CD163 and HMGB1 and were higher in HIV-infected children than in HIV-uninfected children (p<0.01). In HIV-infected children, CRP and PCT were higher in children with SBI compared to those with no detectable bacterial infection (p<0.0005), and PCT and CD163 were higher in non-survivors (p = 0.001, p = 0.05 respectively). In HIV-uninfected children, CRP and PCT were also higher in children with SBI compared to those with no detectable bacterial infection (p<0.0005), and CD163 was higher in non-survivors (p = 0.05). The best predictors of SBI were CRP and PCT, and areas under the curve (AUCs) were 0.81 (95% CI 0.73-0.89) and 0.86 (95% CI 0.79-0.92) respectively. The best marker for predicting death was PCT, AUC 0.61 (95% CI 0.50-0.71). CONCLUSIONS: Admission PCT and CRP are useful markers of invasive bacterial infection in severely ill African children. The study of these markers using rapid tests in a less selected cohort would be important in this setting.

Nitric oxide synthase 2A (NOS2A) polymorphisms are not associated with invasive pneumococcal disease.

BACKGROUND: Streptococcus pneumoniae (pneumococcus) is responsible for over one million deaths per year, with young children, the elderly and immunocompromised individuals being most at risk. Approximately half of East African children have been reported to be asymptomatic carriers of pneumococcus with invasive infection occurring after the disruption of the respiratory membrane which is believed to be caused by the host immune response. Racial incidence of invasive pneumococcal disease (IPD) is higher in certain populations even after adjusting for environmental factors suggesting a genetic component to disease susceptibility. The nitric oxide synthase 2A (NOS2A) gene is responsible for the production of nitric oxide under pathological conditions including host defence against bacterial infection. Nitric oxide is a modulator of apoptotic and inflammatory cascades and endothelial permeability. We hypothesised that genetic variants within this gene may predispose to disease risk and survival. METHODS: A cohort of 299 children with IPD (221 meningitis, 41 pneumonia and 37 with bacteraemia) and 931 age matched controls from Malawi were used in this study. We investigated nine haplotype tagging single nucleotide polymorphisms within the NOS2A gene and compared the presence or absence of the minor alleles in cases and controls and survivors and non-survivors within the cases. RESULTS: We observed no significant associations between cases and controls or with survival in either all IPD cases or in the separate analysis of meningitis cases. A near significant association was obtained for the comparison of rs8078340 in cases and controls (p-value, 0.078). However, results were unadjusted for multiple testing. CONCLUSION: Our results suggest that polymorphic variation within the NOS2A gene does not influence invasive pneumococcal disease susceptibility or survival.

Successful downstream application of the Paxgene Blood RNA system from small blood samples in paediatric patients for quantitative PCR analysis.

BACKGROUND: The challenge of gene expression studies is to reliably quantify levels of transcripts, but this is hindered by a number of factors including sample availability, handling and storage. The PAXgene Blood RNA System includes a stabilizing additive in a plastic evacuated tube, but requires 2.5 mL blood, which makes routine implementation impractical for paediatric use. The aim of this study was to modify the PAXgene Blood RNA System kit protocol for application to small, sick children, without compromising RNA integrity, and subsequently to perform quantitative analysis of ICAM and interleukin-6 gene expression.Aliquots of 0.86 mL PAXgene reagent were put into microtubes and 0.3 mL whole blood added to maintain the same recommended proportions as in the PAXgene evacuated tube system. RNA quality was assessed using the Agilent BioAnalyser 2100 and an in-house TaqMan assay which measures GAPDH transcript integrity by determining 3' to 5' ratios. qPCR analysis was performed on an additional panel of 7 housekeeping genes. Three reference genes (HPRT1, YWHAZ and GAPDH) were identified using the GeNORM algorithm, which were subsequently used to normalising target gene expression levels. ICAM-1 and IL-6 gene expression were measured in 87 Malawian children with invasive pneumococcal disease. RESULTS: Total RNA yield was between 1,114 and 2,950 ng and the BioAnalyser 2100 demonstrated discernible 18s and 28s bands. The cycle threshold values obtained for the seven housekeeping genes were between 15 and 30 and showed good consistency. Median relative ICAM and IL-6 gene expression were significantly reduced in non-survivors compared to survivors (ICAM: 3.56 vs 4.41, p = 0.04, and IL-6: 2.16 vs 6.73, p = 0.02). CONCLUSION: We have successfully modified the PAXgene blood collection system for use in small children and demonstrated preservation of RNA integrity and successful quantitative real-time PCR analysis.