Bacteremia among children admitted to a rural hospital in Kenya.

BACKGROUND: There are few epidemiologic data on invasive bacterial infections among children in sub-Saharan Africa. We studied every acute pediatric admission to a rural district hospital in Kenya to examine the prevalence, incidence, types, and outcome of community-acquired bacteremia. METHODS: Between August 1998 and July 2002, we cultured blood on admission from 19,339 inpatients and calculated the incidence of bacteremia on the basis of the population served by the hospital. RESULTS: Of a total of 1783 infants who were under 60 days old, 228 had bacteremia (12.8 percent), as did 866 of 14,787 children who were 60 or more days of age (5.9 percent). Among infants who were under 60 days old, Escherichia coli and group B streptococci predominated among a broad range of isolates (14 percent and 11 percent, respectively). Among infants who were 60 or more days of age, Streptococcus pneumoniae, nontyphoidal salmonella species, Haemophilus influenzae, and E. coli accounted for more than 70 percent of isolates. The minimal annual incidence of community-acquired bacteremia was estimated at 1457 cases per 100,000 children among infants under a year old, 1080 among children under 2 years, and 505 among children under 5 years. Of all in-hospital deaths, 26 percent were in children with community-acquired bacteremia. Of 308 deaths in children with bacteremia, 103 (33.4 percent) occurred on the day of admission and 217 (70.5 percent) within two days. CONCLUSIONS: Community-acquired bacteremia is a major cause of death among children at a rural sub-Saharan district hospital, a finding that highlights the need for prevention and for overcoming the political and financial barriers to widespread use of existing vaccines for bacterial diseases

Evaluation of the World Health Organization Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network's Laboratory External Quality Assessment Programme, 2014-2019

Introduction. In 2009, the World Health Organization (WHO) established the Global Invasive Bacterial Vaccine Preventable Disease (IB-VPD) Surveillance Network (GISN) to monitor the global burden and aetiology of bacterial meningitis, pneumonia and sepsis caused by Haemophilus influenzae (Hi), Neisseria meningitidis (Nm) and Streptococcus pneumoniae (Sp).Hypothesis/Gap Statement. The GISN established an external quality assessment (EQA) programme for the characterization of Hi, Nm and Sp by culture and diagnostic PCR.Aim. To assess the performance of sentinel site laboratories (SSLs), national laboratories (NLs) and regional reference laboratories (RRLs) between 2014 and 2019 in the EQA programme.Methodology. Test samples consisted of bacterial smears for Gram-staining, viable isolates for identification and serotyping or serogrouping (ST/SG), plus simulated cerebrospinal fluid (CSF) samples for species detection and ST/SG by PCR. SSLs and NLs were only required to analyse the slides for Gram staining and identify the species of the live isolates. RRLs, and any SLs and NLs that had the additional laboratory capacity, were also required to ST/SG the viable isolates and analyse the simulated CSF samples.Results. Across the period, 69-112 SS/NL labs and eight or nine RRLs participated in the EQA exercise. Most participants correctly identified Nm and Sp in Gram-stained smears but were less successful with Hi and other species. SSLs/NLs identified the Hi, Nm and Sp cultures well and also submitted up to 56 % of Hi, 62 % of Nm and 33 % of Sp optional ST/SG results each year. There was an increasing trend in the proportion of correct results submitted over the 6 years for Nm and Sp. Some SSLs/NLs also performed the optional detection and ST/SG of the three organisms by PCR in simulated CSF from 2015 onwards; 89-100 % of the CSF samples were correctly identified and 76-93 % of Hi-, 90-100 % of Nm- and 75-100 % of Sp-positive samples were also correctly ST/SG across the distributions. The RRLs performed all parts of the EQA to a very high standard, with very few errors across all aspects of the EQA.Conclusion. The EQA has been an important tool in maintaining high standards of laboratory testing and building of laboratory capacity in the GISN

Rapid assessment of Hib disease burden in Vietnam

<p>Abstract</p> <p>Background</p> <p>Several countries have applied the <it>Haemophilus influenzae </it>type b (Hib) rapid assessment tool (RAT) to estimate the burden of Hib disease where resources for hospital- or population-based surveillance are limited. In Vietnam, we used the Hib RAT to estimate the burden of Hib pneumonia and meningitis prior to Hib vaccine introduction.</p> <p>Methods</p> <p>Laboratory, hospitalization and mortality data were collected for the period January 2004 through December 2005 from five representative hospitals. Based on the WHO Hib RAT protocol, standardized MS Excel spreadsheets were completed to generate meningitis and pneumonia case and death figures.</p> <p>Results</p> <p>We found 35 to 77 Hib meningitis deaths and 441 to 957 Hib pneumonia deaths among children < 5 years of age annually in Vietnam. Overall, the incidence of Hib meningitis was estimated at 18/100,000 (95% confidence interval, CI, 15.1-21.6). The estimated Hib meningitis incidence in children < 5 years age was higher in Ho Chi Minh City (22.5/100,000 [95% CI, 18.4-27.5]) compared to Hanoi (9.8/100,000 [95% CI, 6.5-14.8]). The Hib RAT suggests that there are a total of 883 to 1,915 cases of Hib meningitis and 4,414 to 9,574 cases of Hib pneumonia per year in Vietnam.</p> <p>Conclusions</p> <p>In Hanoi, the estimated incidence of Hib meningitis for children < 5 years of age was similar to that described in previous population-based studies of Hib meningitis conducted from 1999 through 2002. Results from the Hib RAT suggest that there is a substantial, yet unmeasured, disease burden associated with Hib pneumonia in Vietnamese children.</p

A review of the role of Haemophilus influenzae in community-acquired pneumonia

In an era when Haemophilus influenzae type b (Hib) conjugate vaccine is widely used, the incidence of Hib as a cause of community-acquired pneumonia (CAP) has dramatically declined. Non-typeable H. influenzae (NTHi) strains and, occasionally, other encapsulated serotypes of H. influenzae are now the cause of the majority of invasive H. influenzae infections, including bacteraemic CAP. NTHi have long been recognised as an important cause of lower respiratory tract infection, including pneumonia, in adults, especially those with underlying diseases. The role of NTHi as a cause of non-bacteraemic CAP in children is less clear. In this review the evidence for the role of NTHi and capsulated strains of H. influenzae will be examined. </p

Impact of Haemophilus influenzae Type b conjugate vaccine in Mongolia: prospective population-based surveillance, 2002-2010.

OBJECTIVES: Bacterial meningitis is associated with high mortality and long-term complications. This study assessed the impact of Haemophilus influenzae type b (Hib) conjugate vaccine on childhood bacterial meningitis in Ulaanbaatar, Mongolia. STUDY DESIGN: Prospective, active, population-based surveillance for suspected meningitis in children aged 2-59 months was conducted (February 2002-January 2011) in 6 hospitals. Clinical data, blood, and cerebrospinal fluid were collected. The impact of Hib conjugate vaccine was assessed by comparing Hib and all cause meningitis data in the 3 years preceding pentavalent conjugate vaccine implementation (2002-2004) with 3 years postimplementation (2008-2010). RESULTS: Five hundred eleven cases of suspected meningitis were identified from 2002-2011. Pentavalent conjugate vaccine coverage in December 2005 in Ulaanbaatar city was 97%. The proportion of suspected cases confirmed as Hib meningitis decreased from 25% (50/201) in the prevaccination era to 2% (4/193) in the postvaccination era (P < .0001). The annual incidence of Hib decreased from 28 cases per 100,000 children in 2002-2005 to 2 per 100,000 in 2008-2010 (P < .0001). CONCLUSIONS: This article demonstrates the marked impact of Hib conjugate vaccine introduction on meningitis in Mongolia. It is important to sustain this surveillance system to monitor the long-term impact of Hib conjugate vaccine, as well as other interventions such as pneumococcal and meningococcal vaccines

Association between single-nucleotide polymorphisms in Mal/TIRAP and interleukin-10 genes and susceptibility to invasive haemophilus influenzae serotype b infection in immunized children.

BACKGROUND: The development of invasive Haemophilus influenzae serotype b (Hib) disease after prior immunization with the Hib conjugate vaccine (ie, Hib vaccine failure) is extremely rare, suggesting that affected children may have an underlying genetic susceptibility in their immune response. The objective of this study was to investigate single-nucleotide polymorphisms (SNPs) known to affect function in biologically plausible genes in relation to the risk of Hib vaccine failure and its clinical manifestations. METHODS: The families of UK children with Hib vaccine failure diagnosed during the period October 1992 through December 2005 were identified through enhanced national surveillance and approached for the study at a median interval of 4 years after invasive disease. The Wellcome Trust Case Control Consortium data sets were used as controls. Nineteen functional SNPs in 14 immune response genes were investigated in 172 white children. RESULTS: The recessive homozygous genotype for a SNP in the TIRAP (also known as MAL) gene (rs1893352) that is in strong linkage disequilibrium (r2=0.93) with the known functional Ser180Leu polymorphism in white persons was strongly associated with nonmeningitis cases of Hib vaccine failure (odds ratio, 5.6; 95% confidence interval, 2.7-11.5; P=1.2 x 10(-7)). In addition, the recessive homozygous genotype for another SNP (rs1554286) in strong linkage disequilibrium with both the C-819T (r2=0.87) and C-592A (r2=0.75) promoter polymorphisms in the interleukin-10 gene was associated with epiglottitis only (odds ratio, 5.8; 95% confidence interval, 2.4-14.2; P=1.1 x 10(-5)). CONCLUSIONS: Our findings strongly suggest that the development of invasive Hib disease after prior immunization is in part genetically determined and may direct the immune response to specific clinical manifestations

Long-term complications and risk of other serious infections following invasive Haemophilus influenzae serotype b disease in vaccinated children.

This study describes the long-term complications in children with Haemophilus influenzae serotype b (Hib) vaccine failure and to determine their risk of other serious infections. The families of 323 children with invasive Hib disease after appropriate vaccination (i.e. vaccine failure) were contacted to complete a questionnaire relating to their health and 260 (80.5%) completed the questionnaire. Of the 124 children with meningitis, 18.5% reported serious long-term sequelae and a further 12.1% of parents attributed other problems to Hib meningitis. Overall, 14% (32/231 cases) of otherwise healthy children and 59% (17/29 cases) of children with an underlying condition developed at least one other serious infection requiring hospital admission. In a Poisson regression model, the risk of another serious infection was independently associated with the presence of an underlying medical condition (incidence risk ratio (IRR) 7.6, 95% CI 4.8-12.1; p<0.0001), both parents having had a serious infection (IRR 4.1, 95% CI 1.6-10.3; p=0.003), requirement of more than two antibiotic courses per year (IRR 2.3, 95% CI 1.4-3.6; p=0.001) and the presence of a long-term complication after Hib infection (IRR 1.8, 95% CI 1.1-3.1; p=0.03). Thus, rates of long-term sequelae in children with vaccine failure who developed Hib meningitis are similar to those in unvaccinated children in the pre-vaccine era. One in seven otherwise healthy children (14%) with Hib vaccine failure will go on to suffer another serious infection requiring hospital admission in childhood, which is higher than would be expected for the UK paediatric population

Effectiveness of Haemophilus influenzae type b Conjugate vaccine introduction into routine childhood immunization in Kenya.

CONTEXT: Haemophilus influenzae type b (Hib) conjugate vaccine is not perceived as a public health priority in Africa because data on Hib disease burden and vaccine effectiveness are scarce. Hib immunization was introduced in Kenyan infants in 2001. OBJECTIVE: To define invasive Hib disease incidence and Hib vaccine program effectiveness in Kenya. DESIGN, SETTING, AND PATIENTS: Culture-based surveillance for invasive Hib disease at Kilifi District Hospital from 2000 through 2005 was linked to demographic surveillance of 38,000 children younger than 5 years in Kilifi District, Kenya. Human immunodeficiency virus (HIV) infection and Hib vaccination status were determined for children with Hib disease admitted 2002-2005. INTERVENTIONS: Introduction of conjugate Hib vaccine within the routine childhood immunization program at ages 6, 10, and 14 weeks beginning November 2001. MAIN OUTCOME MEASURES: Incidence of culture-proven Hib invasive disease before and after vaccine introduction and vaccine program effectiveness. RESULTS: Prior to vaccine introduction, the median age of children with Hib was 8 months; case fatality was 23%. Among children younger than 5 years, the annual incidence of invasive Hib disease 1 year before and 1 and 3 years after vaccine introduction was 66, 47, and 7.6 per 100,000, respectively. For children younger than 2 years, incidence was 119, 82, and 16 per 100,000, respectively. In 2004-2005, vaccine effectiveness was 88% (95% confidence interval, 73%-96%) among children younger than 5 years and 87% (95% confidence interval, 66%-96%) among children younger than 2 years. Of 53 children with Hib admitted during 2002-2005, 29 (55%) were age-ineligible to have received vaccine, 12 (23%) had not been vaccinated despite being eligible, and 12 (23%) had received 2 or more doses of vaccine (2 were HIV positive). CONCLUSIONS: In Kenya, introduction of Hib vaccine into the routine childhood immunization program reduced Hib disease incidence among children younger than 5 years to 12% of its baseline level. This impact was not observed until the third year after vaccine introduction

Guidelines for the use and interpretation of assays for monitoring autophagy

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field