Non-typhoidal salmonellae: a management challenge for children with community-acquired invasive disease in tropical African countries

Pharmacokinetics and pharmacodynamics of azithromycin in severe malaria bacterial co-infection in African children (TABS-PKPD): a protocol for a Phase II randomised controlled trial

Background: African children with severe malaria are susceptible to Gram-negative bacterial co-infection, largely non-typhoidal Salmonellae, leading to a substantially higher rates of in-hospital and post-discharge mortality than those without bacteraemia. Current evidence for treating co-infection is lacking, and there is no consensus on the dosage or length of treatment required. We therefore aimed to establish the appropriate dose of oral dispersible azithromycin as an antimicrobial treatment for children with severe malaria and to investigate whether antibiotics can be targeted to those at greatest risk of bacterial co-infection using clinical criteria alone or in combination with rapid diagnostic biomarker tests. Methods: A Phase I/II open-label trial comparing three doses of azithromycin: 10, 15 and 20 mg/kg spanning the lowest to highest mg/kg doses previously demonstrated to be equally effective as parenteral treatment for other salmonellae infection. Children with the highest risk of bacterial infection will receive five days of azithromycin and followed for 90 days. We will generate relevant pharmacokinetic data by sparse sampling during dosing intervals. We will use population pharmacokinetic modelling to determine the optimal azithromycin dose in severe malaria and investigate azithromycin exposure to change in C-reactive protein, a putative marker of sepsis at 72 hours, and microbiological cure (seven-day), alone and as a composite with seven-day survival. We will also evaluate whether a combination of clinical, point-of-care diagnostic tests, and/or biomarkers can accurately identify the sub-group of severe malaria with culture-proven bacteraemia by comparison with a control cohort of children hospitalized with severe malaria at low risk of bacterial co-infection. Discussion: We plan to study azithromycin because of its favourable microbiological spectrum, its inherent antimalarial and immunomodulatory properties and dosing and safety profile. This study will generate new data to inform the design and sample size for definitive Phase III trial evaluation. Registration: ISRCTN49726849 (27 th October 2017).

Pharmacokinetics and pharmacodynamics of azithromycin in severe malaria bacterial co-infection in African children (TABS-PKPD): a protocol for a Phase II randomised controlled trial

Background: African children with severe malaria are susceptible to Gram-negative bacterial co-infection, largely non-typhoidal Salmonellae, leading to a substantially higher rates of in-hospital and post-discharge mortality than those without bacteraemia. Current evidence for treating co-infection is lacking, and there is no consensus on the dosage or length of treatment required. We therefore aimed to establish the appropriate dose of oral dispersible azithromycin as an antimicrobial treatment for children with severe malaria and to investigate whether antibiotics can be targeted to those at greatest risk of bacterial co-infection using clinical criteria alone or in combination with rapid diagnostic biomarker tests. Methods: A Phase I/II open-label trial comparing three doses of azithromycin: 10, 15 and 20 mg/kg spanning the lowest to highest mg/kg doses previously demonstrated to be equally effective as parenteral treatment for other salmonellae infection. Children with the highest risk of bacterial infection will receive five days of azithromycin and followed for 90 days. We will generate relevant pharmacokinetic data by sparse sampling during dosing intervals. We will use population pharmacokinetic modelling to determine the optimal azithromycin dose in severe malaria and investigate azithromycin exposure to change in C-reactive protein, a putative marker of sepsis at 72 hours, and microbiological cure (seven-day), alone and as a composite with seven-day survival. We will also evaluate whether a combination of clinical, point-of-care diagnostic tests, and/or biomarkers can accurately identify the sub-group of severe malaria with culture-proven bacteraemia by comparison with a control cohort of children hospitalized with severe malaria at low risk of bacterial co-infection. Discussion: We plan to study azithromycin because of its favourable microbiological spectrum, its inherent antimalarial and immunomodulatory properties and dosing and safety profile. This study will generate new data to inform the design and sample size for definitive Phase III trial evaluation. Registration: ISRCTN49726849 (27th October 2017).

Invasive non-typhoidal Salmonella infections in sub-Saharan Africa: a systematic review on antimicrobial resistance and treatment

BACKGROUND

Non-typhoidal Salmonella (NTS) are a frequent cause of invasive infections in sub-Saharan Africa. They are frequently multidrug resistant (co-resistant to ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol), and resistance to third-generation cephalosporin and fluoroquinolone non-susceptibility have been reported. Third-generation cephalosporins and fluoroquinolones are often used to treat invasive NTS infections, but azithromycin might be an alternative. However, data on antibiotic treatment efficacy in invasive NTS infections are lacking. In this study, we aimed to assess the spatiotemporal distribution of antimicrobial resistance in invasive NTS infections in sub-Saharan Africa and to describe the available evidence and recommendations on antimicrobial treatment.

METHODS

We conducted a systematic review of all available literature on antimicrobial resistance and treatment in invasive NTS infections. We performed a random effects meta-analysis to assess the temporal distribution of multidrug resistance, third-generation cephalosporin resistance, and fluoroquinolone non-susceptibility. We mapped these data to assess the spatial distribution. We provided a narrative synthesis of the available evidence and recommendations on antimicrobial treatment.

RESULTS

Since 2001, multidrug resistance was observed in 75% of NTS isolates from all sub-Saharan African regions (95% confidence interval, 70-80% and 65-84%). Third-generation cephalosporin resistance emerged in all sub-Saharan African regions and was present in 5% (95% confidence interval, 1-10%) after 2010. Fluoroquinolone non-susceptibility emerged in all sub-Saharan African regions but did not increase over time. Azithromycin resistance was reported in DR Congo. There were no reports on carbapenem resistance. We did not find high-quality evidence on the efficacy of antimicrobial treatment. There were no supranational guidelines. The "Access group" antibiotics ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol and "Watch group" antibiotics ceftriaxone, cefotaxime, and ciprofloxacin were recommended as the first-choice antibiotics in national guidelines or reviews. These also recommended (a switch to) oral fluoroquinolones or azithromycin.

CONCLUSIONS

In addition to the widespread multidrug resistance in invasive NTS infections in sub-Saharan Africa, resistance to third-generation cephalosporins and fluoroquinolone non-susceptibility was present in all regions. There was a lack of data on the efficacy of antimicrobial treatment in these infections, and supranational evidence-based guidelines were absent.

Extraintestinal Foodborne Pathogens

In general, foodborne diseases present themselves with gastrointestinal symptoms caused by bacterial, viral, and parasitic pathogens well established to be foodborne. These pathogens are also associated with extraintestinal clinical manifestations. Recent studies have suggested that Escherichia coli and Klebsiella pneumoniae, which both cause common extraintestinal infections such as urinary tract and bloodstream infections, may also be foodborne. The resolution and separation of these organisms into pathotypes versus commensals by modern genotyping methods have led to the identification of key lineages of these organisms causing outbreaks of extraintestinal infections. These epidemiologic observations suggested common- or point-source exposures, such as contaminated food. Here, we describe the spectrum of extraintestinal illnesses caused by recognized enteric pathogens and then review studies that demonstrate the potential role of extraintestinal pathogenic E. coli (ExPEC) and K. pneumoniae as foodborne pathogens. The impact of global food production and distribution systems on the possible foodborne spread of these pathogens is discussed.

Paediatric Salmonellosis-Differences between Tropical and Sub-Tropical Regions of Queensland, Australia

Salmonellosis is an important cause of morbidity in tropical regions.This study aims to describe the epidemiology of non-typhoidal Salmonellae (NTS) in children presenting to public hospitals in Queensland, Australia, over the past 20 years, with a focus on differences between tropical and sub-tropical zones in the region. This is a retrospective and descriptive cohort study of 8162 NTS positive samples collected in 0–17-year-olds from the Queensland public hospital pathology database (Auslab) over a 20-year period from 1997 to 2016. There were 2951 (36.2%) positive NTS samples collected in tropical zones and 5211 (63.8%) in the sub-tropical zones of Queensland, with a total of 8162 over the region. The tropical zone contributed a disproportionately higher number of positive NTS samples by population sub-analysis. Of the specimens collected, 7421 (90.92%) were faecal, 505 (6.2%) blood, 161 (1.97%) urine, 13 (0.16%) cerebrospinal fluid (CSF) and 62 of other origin. Other categories of specimen types isolated include swab, fluid, aspirate, lavage, bone, tissue, isolate and pus, and these were not included in sub-analysis. The most commonly identified serovars were Salmonella Typhimurium, Salmonella Virchow and Salmonella Saintpaul. This is the first and largest study that emphasises the high burden of invasive and non-invasive NTS infections resulting in hospital presentations in the paediatric population of tropical north Queensland, compared to the sub-tropics.

Presentation of life-threatening invasive nontyphoidal Salmonella disease in Malawian children: A prospective observational study

Nontyphoidal Salmonellae commonly cause invasive disease in African children that is often fatal. The clinical diagnosis of these infections is hampered by the absence of a clear clinical syndrome. Drug resistance means that empirical antibiotic therapy is often ineffective and currently no vaccine is available. The study objective was to identify risk factors for mortality among children presenting to hospital with invasive Salmonella disease in Africa. We conducted a prospective study enrolling consecutive children with microbiologically-confirmed invasive Salmonella disease admitted to Queen Elizabeth Central Hospital, Blantyre, in 2006. Data on clinical presentation, co-morbidities and outcome were used to identify children at risk of inpatient mortality through logistic-regression modeling. Over one calendar year, 263 consecutive children presented with invasive Salmonella disease. Median age was 16 months (range 0-15 years) and 52/256 children (20%; 95%CI 15-25%) died. Nontyphoidal serovars caused 248/263 (94%) of cases. 211/259 (81%) of isolates were multi-drug resistant. 251/263 children presented with bacteremia, 6 with meningitis and 6 with both. Respiratory symptoms were present in 184/240 (77%; 95%CI 71-82%), 123/240 (51%; 95%CI 45-58%) had gastrointestinal symptoms and 101/240 (42%; 95%CI 36-49%) had an overlapping clinical syndrome. Presentation at <7 months (OR 10.0; 95%CI 2.8-35.1), dyspnea (OR 4.2; 95%CI 1.5-12.0) and HIV infection (OR 3.3; 95%CI 1.1-10.2) were independent risk factors for inpatient mortality. Invasive Salmonella disease in Malawi is characterized by high mortality and prevalence of multi-drug resistant isolates, along with non-specific presentation. Young infants, children with dyspnea and HIV-infected children bear a disproportionate burden of the Salmonella-associated mortality in Malawi. Strategies to improve prevention, diagnosis and management of invasive Salmonella disease should be targeted at these children.

Current perspectives on invasive nontyphoidal Salmonella disease

PURPOSE OF REVIEW

We searched PubMed for scientific literature published in the past 2 years for relevant information regarding the burden of invasive nontyphoidal Salmonella disease and host factors associated with nontyphoidal Salmonella infection and discuss current knowledge on vaccine development. The following search terms were used: Salmonella, non typhoidal/nontyphoidal, NTS, disease, bloodstream infection, invasive, sepsis/septicaemia/septicemia, bacteraemia/bacteremia, gastroenteritis, incidence, prevalence, morbidity, mortality, case fatality, host/risk factor, vaccination, and prevention/control.

RECENT FINDINGS

Estimates of the global invasive nontyphoidal Salmonella disease burden have been recently updated; additional data from Africa, Asia, and Latin America are now available. New data bridge various knowledge gaps, particularly with respect to host risk factors and the geographical distribution of iNTS serovars. It has also been observed that Salmonella Typhimurium sequence type 313 is emergent in several African countries. Available data suggest that genetic variation in the sequence type 313 strain has led to increased pathogenicity and human host adaptation. A bivalent efficacious vaccine, targeting Salmonella serovars Typhimurium and Enteritidis, would significantly lower the disease burden in high-risk populations.

SUMMARY

The mobilization of surveillance networks, especially in Asia and Latin America, may provide missing data regarding the invasive nontyphoidal Salmonella disease burden and their corresponding antimicrobial susceptibility profiles. Efforts and resources should be directed toward invasive nontyphoidal Salmonella disease vaccine development.

Child pneumonia - focus on the Western Pacific Region

Worldwide, pneumonia is the leading cause of death in infants and young children (aged <5 years). We provide an overview of the global pneumonia disease burden, as well as the aetiology and management practices in different parts of the world, with a specific focus on the WHO Western Pacific Region. In 2011, the Western Pacific region had an estimated 0.11 pneumonia episodes per child-year with 61,900 pneumonia-related deaths in children less than 5 years of age. The majority (>75%) of pneumonia deaths occurred in six countries; Cambodia, China, Laos, Papua New Guinea, the Philippines and Viet Nam. Historically Streptococcus pneumoniae and Haemophilus influenzae were the commonest causes of severe pneumonia and pneumonia-related deaths in young children, but this is changing with the introduction of highly effective conjugate vaccines and socio-economic development. The relative contribution of viruses and atypical bacteria appear to be increasing and traditional case management approaches may require revision to accommodate increased uptake of conjugated vaccines in the Western Pacific region. Careful consideration should be given to risk reduction strategies, enhanced vaccination coverage, improved management of hypoxaemia and antibiotic stewardship.

Bloodstream Infection Due to CTX-M-15 and TEM-1 Extended-Spectrum β-Lactamase-Producing Salmonella enterica serovar Virchow ST16

A 57-year-old man presented with high fever and diarrhea. A blood culture revealed the presence of a Group C nontyphoidal Salmonella (NTS) isolate. On Salmonella serotyping, the isolate was identified as Salmonella enterica serovar Virchow. Its sequence type was determined to be ST16 by sequence analysis of 7 different housekeeping genes. The bla_CTX-M group 1 and bla_TEM genes were amplified using multiplex PCR assay for detecting extended-spectrum β-lactamases (ESBL) genes. Sequences of both amplicons were respectively identical to CTX-M-15- and TEM-1-encoding genes. Since NTS is a cause of foodborne illness outbreaks in communities and an important cause of community-acquired bloodstream infection, clinicians should consider ESBL- or AmpC-producing NTS species in the differential diagnosis.

Emergence of Community-Acquired, Multidrug-Resistant Invasive Nontyphoidal Salmonella Disease in Rural Western Kenya, 2009-2013

BACKGROUND

Nontyphoidal Salmonella (NTS), mainly serotypes Typhimurium and Enteritidis, cause invasive infections with high mortality in children in sub-Saharan Africa. Multidrug resistance is common, and resistance to third-generation cephalosporins has emerged.

METHODS

We reviewed clinical features, outcomes, and antimicrobial resistance patterns in invasive NTS infections among children aged 6 weeks to 5 years participating in malaria vaccine studies in an area of high malaria and human immunodeficiency virus (HIV) transmission in Siaya, western Kenya. Blood culture was performed in hospitalized children and pediatric outpatients with prolonged fever.

RESULTS

From July 2009 to December 2013, 1696 children aged 6 weeks to 17 months were enrolled into vaccine trials and followed for up to 53 months. We obtained 1692 blood cultures from 847 children. Of 134 bacterial pathogens isolated, 102 (76.1%) were Salmonella serogroup B or D. Invasive NTS disease occurred in 94 (5.5%) children, with an incidence of 1870, 4134, and 6510 episodes per 100 000 person-years overall, in infants, and in HIV-infected children, respectively. Malaria infection within the past 2 weeks occurred in 18.8% (3/16) of invasive NTS episodes in HIV-infected and 66.2% (53/80) in HIV-uninfected children. Case fatality rate was 3.1%. Salmonella group B resistant to ceftriaxone emerged in 2009 and 2010 (6.2% [2/32 isolates]), rising to 56.5% (13/23 isolates) in 2012 and 2013.

CONCLUSIONS

Incidence of invasive NTS disease was high in this area of high malaria and HIV transmission, especially in HIV-infected children. Rapidly emerging resistance against ceftriaxone requires urgent reevaluation of antibiotic recommendations and primary prevention of exposure to Salmonella.

Microbiological, clinical and molecular findings of non-typhoidal Salmonella bloodstream infections associated with malaria, Oriental Province, Democratic Republic of the Congo

Background

In sub-Saharan Africa, non-typhoidal Salmonella (NTS) can cause bloodstream infections, referred to as invasive non-typhoidal Salmonella disease (iNTS disease); it can occur in outbreaks and is often preceded by malaria. Data from Central Africa is limited.

Methods

Clinical, microbiological and molecular findings of NTS recovered in a blood culture surveillance project (2009–2014) were analyzed.

Results

In March-July 2012 there was an epidemic increase in malaria infections in the Oriental Province of the Democratic Republic of the Congo (DRC). In one referral hospital, overall hospital admissions in June 2012 were 2.6 times higher as compared to the same period in the years before and after (336 versus an average of 128 respectively); numbers of malaria cases and blood transfusions were nearly three- and five-fold higher respectively (317 versus 112 and 250 versus 55). Case fatality rates (in-hospital deaths versus all admissions) peaked at 14.6 %. Salmonella Typhimurium and Salmonella Enteritidis together accounted for 88.9 % of pathogens isolated from blood cultures collected during an outreach visit to the affected districts in June 2012. Children infected with Salmonella Enteritidis (33 patient files available) tended to be co-infected with Plasmodium falciparum more often than children infected with Salmonella Typhimurium (40 patients files available) (81.8 % versus 62.5 %). Through the microbiological surveillance project (May 2009–May 2014) 113 unique NTS isolates were collected (28.5 % (113/396) of pathogens); most (95.3 %) were recovered from children < 15 years. Salmonella Typhimurium (n = 54) and Salmonella Enteritidis (n = 56) accounted for 47.8 % and of 49.6 % NTS isolates respectively. Multilocus variable-number tandem-repeat analysis (MLVA) revealed more heterogeneity for Salmonella Typhimurium than for Salmonella Enteritidis. Most (82/96, 85.4 %) NTS isolates that were available for antibiotic susceptibility testing were multidrug resistant. All isolates were susceptible to ceftriaxone and azithromycin.

Conclusion

During the peak of an epidemic increase in malaria in the DRC in 2012, a high proportion of multidrug resistant Salmonella Typhimurium and Salmonella Enteritidis were isolated from blood cultures. Overall, the two serovars showed subtle differences in clinical presentation and genetic diversity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1604-1) contains supplementary material, which is available to authorized users.

Towards Improving Point-of-Care Diagnosis of Non-malaria Febrile Illness: A Metabolomics Approach

Introduction

Non-malaria febrile illnesses such as bacterial bloodstream infections (BSI) are a leading cause of disease and mortality in the tropics. However, there are no reliable, simple diagnostic tests for identifying BSI or other severe non-malaria febrile illnesses. We hypothesized that different infectious agents responsible for severe febrile illness would impact on the host metabololome in different ways, and investigated the potential of plasma metabolites for diagnosis of non-malaria febrile illness.

Methodology

We conducted a comprehensive mass-spectrometry based metabolomics analysis of the plasma of 61 children with severe febrile illness from a malaria-endemic rural African setting. Metabolite features characteristic for non-malaria febrile illness, BSI, severe anemia and poor clinical outcome were identified by receiver operating curve analysis.

Principal Findings

The plasma metabolome profile of malaria and non-malaria patients revealed fundamental differences in host response, including a differential activation of the hypothalamic-pituitary-adrenal axis. A simple corticosteroid signature was a good classifier of severe malaria and non-malaria febrile patients (AUC 0.82, 95% CI: 0.70–0.93). Patients with BSI were characterized by upregulated plasma bile metabolites; a signature of two bile metabolites was estimated to have a sensitivity of 98.1% (95% CI: 80.2–100) and a specificity of 82.9% (95% CI: 54.7–99.9) to detect BSI in children younger than 5 years. This BSI signature demonstrates that host metabolites can have a superior diagnostic sensitivity compared to pathogen-detecting tests to identify infections characterized by low pathogen load such as BSI.

Conclusions

This study demonstrates the potential use of plasma metabolites to identify causality in children with severe febrile illness in malaria-endemic settings.

In the tropics, malaria is commonly attributed to be the cause of most childhood fevers, while in fact this condition is more commonly caused by other pathogens that are clinically indistinguishable from malaria. These so-called non-malaria febrile illnesses include bacterial bloodstream infections, which are associated with a higher mortality than malaria. Most health care facilities in the tropics have malaria diagnostic tests available, but tests for non-malarial febrile illnesses are extremely limited. There is the critical need for new tests that can address the question ‘if a febrile patient is not suffering from malaria, then what is it and what treatment will be effective?’ Using metabolomics, we have comprehensively screened the biochemical profile of patients with severe febrile illness for biological markers of non-malaria febrile illness. The results show that severe malaria and non-malaria febrile illness trigger a distinct metabolic response in the host. We demonstrate that this pathophysiological difference can be exploited for differential diagnosis of severe febrile illness and identification of patients with bacterial bloodstream infections.

Routine Amoxicillin for Uncomplicated Severe Acute Malnutrition in Children

BACKGROUND

High-quality evidence supporting a community-based treatment protocol for children with severe acute malnutrition, including routine antibiotic use at admission to a nutritional treatment program, remains limited. In view of the costs and consequences of emerging resistance associated with routine antibiotic use, more evidence is required to support this practice.

METHODS

In a double-blind, placebo-controlled trial in Niger, we randomly assigned children who were 6 to 59 months of age and had uncomplicated severe acute malnutrition to receive amoxicillin or placebo for 7 days. The primary outcome was nutritional recovery at or before week 8.

RESULTS

A total of 2412 children underwent randomization, and 2399 children were included in the analysis. Nutritional recovery occurred in 65.9% of children in the amoxicillin group (790 of 1199) and in 62.7% of children in the placebo group (752 of 1200). There was no significant difference in the likelihood of nutritional recovery (risk ratio for amoxicillin vs. placebo, 1.05; 95% confidence interval [CI], 0.99 to 1.12; P=0.10). In secondary analyses, amoxicillin decreased the risk of transfer to inpatient care by 14% (26.4% in the amoxicillin group vs. 30.7% in the placebo group; risk ratio, 0.86; 95% CI, 0.76 to 0.98; P=0.02).

CONCLUSIONS

We found no benefit of routine antibiotic use with respect to nutritional recovery from uncomplicated severe acute malnutrition in Niger. In regions with adequate infrastructure for surveillance and management of complications, health care facilities could consider eliminating the routine use of antibiotics in protocols for the treatment of uncomplicated severe acute malnutrition. (Funded by Médecins sans Frontières Operational Center Paris; ClinicalTrials.gov number, NCT01613547.).

Epidemiology, Clinical Presentation, Laboratory Diagnosis, Antimicrobial Resistance, and Antimicrobial Management of Invasive Salmonella Infections

Salmonella enterica infections are common causes of bloodstream infection in low-resource areas, where they may be difficult to distinguish from other febrile illnesses and may be associated with a high case fatality ratio. Microbiologic culture of blood or bone marrow remains the mainstay of laboratory diagnosis. Antimicrobial resistance has emerged in Salmonella enterica, initially to the traditional first-line drugs chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole. Decreased fluoroquinolone susceptibility and then fluoroquinolone resistance have developed in association with chromosomal mutations in the quinolone resistance-determining region of genes encoding DNA gyrase and topoisomerase IV and also by plasmid-mediated resistance mechanisms. Resistance to extended-spectrum cephalosporins has occurred more often in nontyphoidal than in typhoidal Salmonella strains. Azithromycin is effective for the management of uncomplicated typhoid fever and may serve as an alternative oral drug in areas where fluoroquinolone resistance is common. In 2013, CLSI lowered the ciprofloxacin susceptibility breakpoints to account for accumulating clinical, microbiologic, and pharmacokinetic-pharmacodynamic data suggesting that revision was needed for contemporary invasive Salmonella infections. Newly established CLSI guidelines for azithromycin and Salmonella enterica serovar Typhi were published in CLSI document M100 in 2015.

Reducing deaths from severe pneumonia in children in Malawi by improving delivery of pneumonia case management

OBJECTIVE

To evaluate the pneumonia specific case fatality rate over time following the implementation of a Child Lung Health Programme (CLHP) within the existing government health services in Malawi to improve delivery of pneumonia case management.

METHODS

A prospective, nationwide public health intervention was studied to evaluate the impact on pneumonia specific case fatality rate (CFR) in infants and young children (0 to 59 months of age) following the implementation of the CLHP. The implementation was step-wise from October 1st 2000 until 31st December 2005 within paediatric inpatient wards in 24 of 25 district hospitals in Malawi. Data analysis compared recorded outcomes in the first three months of the intervention (the control period) to the period after that, looking at trend over time and variation by calendar month, age group, severity of disease and region of the country. The analysis was repeated standardizing the follow-up period by using only the first 15 months after implementation at each district hospital.

FINDINGS

Following implementation, 47,228 children were admitted to hospital for severe/very severe pneumonia with an overall CFR of 9.8%. In both analyses, the highest CFR was in the children 2 to 11 months, and those with very severe pneumonia. The majority (64%) of cases, 2-59 months, had severe pneumonia. In this group there was a significant effect of the intervention Odds Ratio (OR) 0.70 (95%CI: 0.50-0.98); p = 0.036), while in the same age group children treated for very severe pneumonia there was no interventional benefit (OR 0.97 (95%CI: 0.72-1.30); p = 0.8). No benefit was observed for neonates (OR 0.83 (95%CI: 0.56-1.22); p = 0.335).

CONCLUSIONS

The nationwide implementation of the CLHP significantly reduced CFR in Malawian infants and children (2-59 months) treated for severe pneumonia. Reasons for the lack of benefit for neonates, infants and children with very severe pneumonia requires further research.

Vaccines against invasive Salmonella disease: current status and future directions

Though primarily enteric pathogens, Salmonellae are responsible for a considerable yet under-appreciated global burden of invasive disease. In South and South-East Asia, this manifests as enteric fever caused by serovars Typhi and Paratyphi A. In sub-Saharan Africa, a similar disease burden results from invasive nontyphoidal Salmonellae, principally serovars Typhimurium and Enteritidis. The existing Ty21a live-attenuated and Vi capsular polysaccharide vaccines target S. Typhi and are not effective in young children where the burden of invasive Salmonella disease is highest. After years of lack of investment in new Salmonella vaccines, recent times have seen increased interest in the area led by emerging-market manufacturers, global health vaccine institutes and academic partners. New glycoconjugate vaccines against S. Typhi are becoming available with similar vaccines against other invasive serovars in development. With other new vaccines under investigation, including live-attenuated, protein-based and GMMA vaccines, now is an exciting time for the Salmonella vaccine field.

Invasive bacterial co-infection in African children with Plasmodium falciparum malaria: a systematic review

BACKGROUND

Severe malaria remains a major cause of pediatric hospital admission across Africa. Invasive bacterial infection (IBI) is a recognized complication of Plasmodium falciparum malaria, resulting in a substantially worse outcome. Whether a biological relationship exists between malaria infection and IBI susceptibility remains unclear. We, therefore, examined the extent, nature and evidence of this association.

METHODS

We conducted a systematic search in August 2012 of three major scientific databases, PubMed, Embase and Africa Wide Information, for articles describing bacterial infection among children with P. falciparum malaria using the search string '(malaria OR plasmodium) AND (bacteria OR bacterial OR bacteremia OR bacteraemia OR sepsis OR septicaemia OR septicemia).' Eligiblity criteria also included studies of children hospitalized with malaria or outpatient attendances in sub-Saharan Africa.

RESULTS

A total of 25 studies across 11 African countries fulfilled our criteria. They comprised twenty cohort analyses, two randomized controlled trials and three prospective epidemiological studies. In the meta-analysis of 7,208 children with severe malaria the mean prevalence of IBI was 6.4% (95% confidence interval (CI) 5.81 to 6.98%). In a further meta-analysis of 20,889 children hospitalised with all-severity malaria and 27,641 children with non-malarial febrile illness the mean prevalence of IBI was 5.58 (95% CI 5.5 to 5.66%) in children with malaria and 7.77% (95% CI 7.72 to 7.83%) in non-malaria illness. Ten studies reported mortality stratified by IBI. Case fatality was higher at 81 of 336, 24.1% (95% CI 18.9 to 29.4) in children with malaria/IBI co-infection compared to 585 of 5,760, 10.2% (95% CI 9.3 to 10.98) with malaria alone. Enteric gram-negative organisms were over-represented in malaria cases, non-typhoidal Salmonellae being the most commonest isolate. There was weak evidence indicating IBI was more common in the severe anemia manifestation of severe malaria.

CONCLUSIONS

The accumulated evidence suggests that children with recent or acute malaria are at risk of bacterial infection, which results in an increased risk of mortality. Characterising the exact nature of this association is challenging due to the paucity of appropriate severity-matched controls and the heterogeneous data. Further research to define those at greatest risk is necessary to target antimicrobial treatment.

Etiology of severe non-malaria febrile illness in Northern Tanzania: a prospective cohort study

Introduction

The syndrome of fever is a commonly presenting complaint among persons seeking healthcare in low-resource areas, yet the public health community has not approached fever in a comprehensive manner. In many areas, malaria is over-diagnosed, and patients without malaria have poor outcomes.

Methods and Findings

We prospectively studied a cohort of 870 pediatric and adult febrile admissions to two hospitals in northern Tanzania over the period of one year using conventional standard diagnostic tests to establish fever etiology. Malaria was the clinical diagnosis for 528 (60.7%), but was the actual cause of fever in only 14 (1.6%). By contrast, bacterial, mycobacterial, and fungal bloodstream infections accounted for 85 (9.8%), 14 (1.6%), and 25 (2.9%) febrile admissions, respectively. Acute bacterial zoonoses were identified among 118 (26.2%) of febrile admissions; 16 (13.6%) had brucellosis, 40 (33.9%) leptospirosis, 24 (20.3%) had Q fever, 36 (30.5%) had spotted fever group rickettsioses, and 2 (1.8%) had typhus group rickettsioses. In addition, 55 (7.9%) participants had a confirmed acute arbovirus infection, all due to chikungunya. No patient had a bacterial zoonosis or an arbovirus infection included in the admission differential diagnosis.

Conclusions

Malaria was uncommon and over-diagnosed, whereas invasive infections were underappreciated. Bacterial zoonoses and arbovirus infections were highly prevalent yet overlooked. An integrated approach to the syndrome of fever in resource-limited areas is needed to improve patient outcomes and to rationally target disease control efforts.

The syndrome of fever is caused by a large number of infectious diseases. Malaria is thought to have been declining in the tropics since 2004. Increasing use of malaria diagnostic tests reveal a growing proportion of patients with fever who do not have malaria. While malaria diagnostic tests may be available, healthcare workers have few tools to diagnose causes of fever other than malaria. In order to identify major causes of fever other than malaria in northern Tanzania, we studied 870 patients with fever who were sufficiently ill to require admission to hospital. Malaria was uncommon and over-diagnosed, whereas invasive infections, including bloodstream infections, were underappreciated. Infections associated with animals such as brucellosis, leptospirosis, Q fever, and spotted fever group rickettsioses as well as viral infections transmitted by mosquitoes were common yet overlooked. We recommend that research on the syndrome of fever in resource-limited areas should focus on a wide range of potential causes. Animal-associated infections should be prioritized in patient management and disease control.

Infections in children admitted with complicated severe acute malnutrition in Niger

Background

Although malnutrition affects thousands of children throughout the Sahel each year and predisposes them to infections, there is little data on the etiology of infections in these populations. We present a clinical and biological characterization of infections in hospitalized children with complicated severe acute malnutrition (SAM) in Maradi, Niger.

Methods

Children with complicated SAM hospitalized in the intensive care unit of a therapeutic feeding center, with no antibiotics in the previous 7 days, were included. A clinical examination, blood, urine and stool cultures, and chest radiography were performed systematically on admission.

Results

Among the 311 children included in the study, gastroenteritis was the most frequent clinical diagnosis on admission, followed by respiratory tract infections and malaria. Blood or urine culture was positive in 17% and 16% of cases, respectively, and 36% had abnormal chest radiography. Enterobacteria were sensitive to most antibiotics, except amoxicillin and cotrimoxazole. Twenty-nine (9%) children died, most frequently from sepsis. Clinical signs were poor indicators of infection and initial diagnoses correlated poorly with biologically or radiography-confirmed diagnoses.

Conclusions

These data confirm the high level of infections and poor correlation with clinical signs in children with complicated SAM, and provide antibiotic resistance profiles from an area with limited microbiological data. These results contribute unique data to the ongoing debate on the use and choice of broad-spectrum antibiotics as first-line treatment in children with complicated SAM and reinforce the call for an update of international guidelines on management of complicated SAM based on more recent data.

Invasive non-typhoidal salmonella disease: an emerging and neglected tropical disease in Africa

Invasive strains of non-typhoidal salmonellae have emerged as a prominent cause of bloodstream infection in African adults and children, with an associated case fatality of 20-25%. The clinical presentation of invasive non-typhoidal salmonella disease in Africa is diverse: fever, hepatosplenomegaly, and respiratory symptoms are common, and features of enterocolitis are often absent. The most important risk factors are HIV infection in adults, and malaria, HIV, and malnutrition in children. A distinct genotype of Salmonella enterica var Typhimurium, ST313, has emerged as a new pathogenic clade in sub-Saharan Africa, and might have adapted to cause invasive disease in human beings. Multidrug-resistant ST313 has caused epidemics in several African countries, and has driven the use of expensive antimicrobial drugs in the poorest health services in the world. Studies of systemic cellular and humoral immune responses in adults infected with HIV have revealed key host immune defects contributing to invasive non-typhoidal salmonella disease. This emerging pathogen might therefore have adapted to occupy an ecological and immunological niche provided by HIV, malaria, and malnutrition in Africa. A good understanding of the epidemiology of this neglected disease will open new avenues for development and implementation of vaccine and public health strategies to prevent infections and interrupt transmission.

Development of mature and functional human myeloid subsets in hematopoietic stem cell-engrafted NOD/SCID/IL2rγKO mice

Although physiological development of human lymphoid subsets has become well documented in humanized mice, in vivo development of human myeloid subsets in a xenotransplantation setting has remained unevaluated. Therefore, we investigated in vivo differentiation and function of human myeloid subsets in NOD/SCID/IL2rγ(null) (NSG) mouse recipients transplanted with purified lineage(-)CD34(+)CD38(-) cord blood hematopoietic stem cells. At 4-6 mo posttransplantation, we identified the development of human neutrophils, basophils, mast cells, monocytes, and conventional and plasmacytoid dendritic cells in the recipient hematopoietic organs. The tissue distribution and morphology of these human myeloid cells were similar to those identified in humans. After cytokine stimulation in vitro, phosphorylation of STAT molecules was observed in neutrophils and monocytes. In vivo administration of human G-CSF resulted in the recruitment of human myeloid cells into the recipient circulation. Flow cytometry and confocal imaging demonstrated that human bone marrow monocytes and alveolar macrophages in the recipients displayed intact phagocytic function. Human bone marrow-derived monocytes/macrophages were further confirmed to exhibit phagocytosis and killing of Salmonella typhimurium upon IFN-γ stimulation. These findings demonstrate the development of mature and functionally intact human myeloid subsets in vivo in the NSG recipients. In vivo human myelopoiesis established in the NSG humanized mouse system may facilitate the investigation of human myeloid cell biology including in vivo analyses of infectious diseases and therapeutic interventions.

Salmonella infections: an update on epidemiology, management, and prevention

Salmonella species are a group of Gram-negative enterobacteria and known human pathogens in developing as well as industrialized countries. Despite significant advances in sanitation, provision of potable water, and highly controlled food chain surveillance, transmission of Salmonella spp. continues to affect communities, preferentially children, worldwide. This review summarizes updated concepts on typhoidal and non-typhoidal Salmonella infections, starting with a historical perspective that implicates typhoid Salmonella as a significant human pathogen since ancient times. We describe the epidemiology of this pathogen with emphasis on the most recent non-typhoidal Salmonella outbreaks in industrialized countries and continued outbreaks of typhoid Salmonella in underserved countries. An overview of clinical aspects of typhoid and non-typhoid infections in developing and industrialized countries, respectively, is provided, followed by a description on current treatment concepts and challenges treating multidrug-resistant Salmonella infections. We conclude with prevention recommendations, and recent research studies on vaccine prevention.

Invasive nontyphoidal Salmonella disease: epidemiology, pathogenesis and diagnosis

PURPOSE OF REVIEW

This review highlights and discusses important publications over the past 12 months providing new insights on invasive nontyphoidal Salmonella (iNTS) disease.

RECENT FINDINGS

There have been informative new estimates of the burden of iNTS in Asia and in high-resource, low-incidence settings. Important information has emerged in the last year about the relationships between HIV, malaria, iNTS and typhoid fever in adults and children in Africa. HIV causes susceptibility to iNTS disease, but has been shown to be protective against typhoid fever. Clinical guidelines for presumptive diagnosis frequently fail to identify iNTS disease in Africa, and there remains a need for improved diagnostic tools. Experimental studies in humans have helped us to understand the intracellular pathogenesis of iNTS and to direct the search for appropriate protein vaccine targets.

SUMMARY

The most important remaining gap in our knowledge is probably an understanding of how NTS is transmitted, and the nature of the relationship between diarrhoeal disease, carriage and invasive disease in Africa, so that diagnostic and prevention tools can be appropriately directed.

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.

Systemic bacteraemia in children presenting with clinical pneumonia and the impact of non-typhoid salmonella (NTS)

Background

The diagnosis and antimicrobial treatment of pneumonia in African children in the absence of diagnostic means such as x-ray facilities or microbiological laboratories relies primarily on clinical symptoms presented by the patients. In order to assess the spectrum of bacterial pathogens, blood cultures were performed in children fulfilling the clinical criteria of pneumonia.

Methods

In total, 1032 blood cultures were taken from children between 2 months and 5 years of age who were admitted to a rural hospital in Ghana between September 2007 and July 2009. Pneumonia was diagnosed clinically and according to WHO criteria classified as "non-severe pneumonia" and "severe pneumonia" ("severe pneumonia" includes the WHO categories "severe pneumonia" and "very severe pneumonia").

Results

The proportion of bacteriaemia with non-typhoid salmonella (NTS) was similar in children with pneumonia (16/173, 9.2%) compared to children hospitalized for other reasons (112/859, 13%). NTS were the predominant organisms isolated from children with clinical pneumonia and significantly more frequent than Streptococcus pneumoniae (8/173, 4.6%). Nine percent (9/101) of children presenting with severe pneumonia and 10% (7/72) of children with non-severe pneumonia were infected with NTS. Nineteen out of 123 NTS isolates (15%) were susceptible to aminopenicillins (amoxycillin/ampicillin), 23/127 (18%) to chlorampenicol, and 23/98 (23%) to co-trimoxazole. All NTS isolates were sensitive to ceftriaxone and ciprofloxacin.

Conclusion

In Sub-saharan Africa, sepsis with NTS should be considered in children with symptoms of pneumonia and aminopenicillins might often not be the adequate drugs for treatment.

Antimicrobial drug resistance trends of bacteremia isolates in a rural hospital in southern Mozambique

Antibiotic resistance in Africa is increasing but insufficiently recognized as a public health problem. However, there are scarce data for antimicrobial resistance trends among bloodstream isolates in sub-Saharan Africa. Antimicrobial drug resistance trends among bacteria isolated from blood of children < 15 years of age admitted to the Manhiça District Hospital in Mozambique during May 2001-April 2006 were monitored by disk diffusion. We documented a linear trend of increasing resistance throughout the study period to chloramphenicol among isolates of Non-typhi Salmonella (P < 0.001), Escherichia coli (P = 0.002), Staphylococcus aureus (P < 0.001), and Haemophilus influenzae (P < 0.001). Increasing resistance to ampicillin was also observed for H. influenzae isolates (P < 0.001). We report trends of increasing resistance among the most frequent etiologies of bacteremia to the most commonly used antibiotics for empirical therapy in this community. Quinolones and third-generation cephalosporines may be needed in the short term to manage community-acquired infections.

Procession to pediatric bacteremia and sepsis: covert operations and failures in diplomacy

Despite advances in diagnosis and treatment, bacterial sepsis remains a major cause of pediatric morbidity and mortality, particularly among neonates, the critically ill, and the growing immunocompromised patient population. Sepsis is the end point of a complex and dynamic series of events in which both host and microbial factors drive high morbidity and potentially lethal physiologic alterations. In this article we provide a succinct overview of the events that lead to pediatric bloodstream infections (BSIs) and sepsis, with a focus on the molecular mechanisms used by bacteria to subvert host barriers and local immunity to gain access to and persist within the systemic circulation. In the events preceding and during BSI and sepsis, Gram-positive and Gram-negative pathogens use a battery of factors for translocation, inhibition of immunity, molecular mimicry, intracellular survival, and nutrient scavenging. Gaps in understanding the molecular pathogenesis of bacterial BSIs and sepsis are highlighted as opportunities to identify and develop new therapeutics.

Impact of HIV on standard case management for severe pneumonia in children

It is estimated that 2 million children under 5 years of age die from pneumonia each year and that half of these deaths occur in sub-Saharan Africa. Over 85% of the more than 2.3 million children living with HIV worldwide reside in sub-Saharan Africa. HIV infection is likely to have a major impact on current recommendations for the standard case management of pneumonia in children and is the rationale for undertaking this review of published studies. The studies identified indicate an overall sixfold (range 2.5-13.5-fold) increase in pneumonia-related fatality in HIV-infected compared with HIV-uninfected African infants and children. They are more likely to have disease due to mixed infection and from a wider range of pathogens including Pneumocystis pneumonia, TB and cytomegalovirus. Scaling-up of the implementation of strategies that prevent HIV and Pneumocystis pneumonia remains an important strategy to reduce the burden of HIV-related pneumonia in the region. Research is urgently required to address the most effective pneumonia case management strategy in HIV-infected infants and children.

Microbiologic and clinical features of Salmonella species isolated from bacteremic children in eastern Democratic Republic of Congo

BACKGROUND

The morbidity of Salmonella bloodstream infections is unacceptably high in Africa. In 2000, the WHO Global Salmonella-Surveillance (GSS) program was founded to reduce the health burden of foodborne diseases. The incorporation, in 2002, of the Democratic Republic of Congo (DRC) in this program allowed the improvement of laboratory capacities. In this retrospective study, we describe the first signs of impact the GSS program has had in DRC in the management of bacteremia.

METHODS

Between 2002 and 2006, we evaluated, in one pediatric hospital, the microbiologic and clinical features of Salmonella isolated from children suspected of having bacteremia. A random selection of isolates was typed by pulsed field gel electrophoresis (PFGE).

RESULTS

Among the 1528 children included in the study, 26.8% were bacteremic. Salmonella accounted for 59% of all bloodstream infections. Salmonella typhimurium (60.5%) and Salmonella enteritidis (22.3%) were the most common Salmonella serotypes. In total, 92.4% were resistant to at least 3 antimicrobials with the following proportion of strains resistant to: ampicillin (86%), chloramphenicol (92%), trimethoprim/sulfamethoxazole (95%), and tetracycline (34%). In 2002, 32.1% of children received an appropriate empiric antimicrobial treatment. In 2006, with the restoration of the confidence in the results provided by the laboratory, we observed an increase of the proportion of patients appropriately (82.9%) treated with antimicrobials (P < 0.01) without any decrease in the overall mortality rates associated with salmonellae bacteremia.

CONCLUSIONS

Our findings indicate the benefit to strengthen laboratory capacities in Africa, allowing the development of management guidelines of bloodstream infection.

A decline in the incidence of invasive non-typhoidal Salmonella infection in The Gambia temporally associated with a decline in malaria infection

Background

Malaria is a risk factor for invasive non-typhoidal Salmonella (NTS) infection in children. In the last 10 years, indices of malaria infection in The Gambia have fallen substantially.

Methods

We compared temporal trends of childhood malaria and NTS infection in two Gambian locations. In Fajara, on the coast, the incidence of NTS infection at three time points between 1979 and 2005 was compared to the percentage of malaria positive outpatient thick blood films and the percentage of admissions associated with malaria over time. In Basse, in the eastern part of the country, the incidence of NTS infection at three time points between 1989 and 2008 was compared to the prevalence of malaria parasitaemia at four time points between 1992 and 2008.

Results

The estimated incidence of NTS infection in Fajara fell from 60 (1979–1984) to 10 (2003–05) cases per 100,000 person years. The proportion of outpatients in Fajara with suspected malaria who were parasitaemic fell from 33% (1999) to 6% (2007) while the proportion of admissions associated with malaria fell from 14.5% (1999) to 5% (2007). In Basse, the estimated incidence of NTS infection fell from 105 (1989–1991) to 29 (2008) cases per 100,000 person years while the prevalence of malaria parasitaemia fell from 45% (1992) to 10% (2008). The incidence of pneumococcal bacteraemia in Fajara and Basse did not fall over the study period.

Conclusions

These data support an association between malaria and NTS infection. Reductions in malaria infection may be associated with reduced rates of invasive childhood NTS infection.

Malaria in children

The past decade has seen an unprecedented surge in political commitment and international funding for malaria control. Coverage with existing control methods (ie, vector control and artemisinin-based combination therapy) is increasing, and, in some Asian and African countries, childhood morbidity and mortality from malaria caused by Plasmodium falciparum are starting to decline. Consequently, there is now renewed interest in the possibility of malaria elimination. But the ability of the parasite to develop resistance to antimalarial drugs and increasing insecticide resistance of the vector threaten to reduce and even reverse current gains. Plasmodium vivax, with its dormant liver stage, will be particularly difficult to eliminate, and access to effective and affordable treatment at community level is a key challenge. New drugs and insecticides are needed urgently, while use of an effective vaccine as part of national malaria control programmes remains an elusive goal. This Seminar, which is aimed at clinicians who manage children with malaria, especially in resource-poor settings, discusses present knowledge and controversies in relation to the epidemiology, pathophysiology, diagnosis, treatment, and prevention of malaria in children.

WHO guidelines for antimicrobial treatment in children admitted to hospital in an area of intense Plasmodium falciparum transmission: prospective study

OBJECTIVES

To assess the performance of WHO's "Guidelines for care at the first-referral level in developing countries" in an area of intense malaria transmission and identify bacterial infections in children with and without malaria.

DESIGN

Prospective study.

SETTING

District hospital in Muheza, northeast Tanzania.

PARTICIPANTS

Children aged 2 months to 13 years admitted to hospital for febrile illness.

MAIN OUTCOME MEASURES

Sensitivity and specificity of WHO guidelines in diagnosing invasive bacterial disease; susceptibility of isolated organisms to recommended antimicrobials.

RESULTS

Over one year, 3639 children were enrolled and 184 (5.1%) died; 2195 (60.3%) were blood slide positive for Plasmodium falciparum, 341 (9.4%) had invasive bacterial disease, and 142 (3.9%) were seropositive for HIV. The prevalence of invasive bacterial disease was lower in slide positive children (100/2195, 4.6%) than in slide negative children (241/1444, 16.7%). Non-typhi Salmonella was the most frequently isolated organism (52/100 (52%) of organisms in slide positive children and 108/241 (45%) in slide negative children). Mortality among children with invasive bacterial disease was significantly higher (58/341, 17%) than in children without invasive bacterial disease (126/3298, 3.8%) (P<0.001), and this was true regardless of the presence of P falciparum parasitaemia. The sensitivity and specificity of WHO criteria in identifying invasive bacterial disease in slide positive children were 60.0% (95% confidence interval 58.0% to 62.1%) and 53.5% (51.4% to 55.6%), compared with 70.5% (68.2% to 72.9%) and 48.1% (45.6% to 50.7%) in slide negative children. In children with WHO criteria for invasive bacterial disease, only 99/211(47%) of isolated organisms were susceptible to the first recommended antimicrobial agent.

CONCLUSIONS

In an area exposed to high transmission of malaria, current WHO guidelines failed to identify almost a third of children with invasive bacterial disease, and more than half of the organisms isolated were not susceptible to currently recommended antimicrobials. Improved diagnosis and treatment of invasive bacterial disease are needed to reduce childhood mortality.