Aetiology and outcomes of sepsis in adults in sub-Saharan Africa: a systematic review and meta-analysis

Background Aetiology and outcomes of sepsis in sub-Saharan Africa (sSA) are poorly described; we performed a systematic review and meta-analysis to summarise the available data. Methods Systematic searches of PubMed and Scopus were undertaken to identify prospective studies recruiting adults (> 13 years) with community-acquired sepsis in sSA post-2000. Random effects meta-analysis of in-hospital and 30-day mortality was undertaken and available aetiology data also summarised by random effects meta-analysis. Results Fifteen studies of 2800 participants were identified. Inclusion criteria were heterogeneous. The majority of patients were HIV-infected, and Mycobacterium tuberculosis was the most common cause of blood stream infection where sought. Pooled in-hospital mortality for Sepsis-2-defined sepsis and severe sepsis was 19% (95% CI 12–29%) and 39% (95% CI 30–47%) respectively, and sepsis mortality was associated with the proportion of HIV-infected participants. Mortality and morbidity data beyond 30 days were absent. Conclusions Sepsis in sSA is dominated by HIV and tuberculosis, with poor outcomes. Optimal antimicrobial strategies, including the role of tuberculosis treatment, are unclear. Long-term outcome data are lacking. Standardised sepsis diagnostic criteria that are easily applied in low-resource settings are needed to establish an evidence base for sepsis management in sSA

rPinecone : Define sub-lineages of a clonal expansion via a phylogenetic tree

The ability to distinguish different circulating pathogen clones from each other is a fundamental requirement to understand the epidemiology of infectious diseases. Phylogenetic analysis of genomic data can provide a powerful platform to identify lineages within bacterial populations, and thus inform outbreak investigation and transmission dynamics. However, resolving differences between pathogens associated with low-variant (LV) populations carrying low median pairwise single nucleotide variant (SNV) distances remains a major challenge. Here we present rPinecone, an R package designed to define sub-lineages within closely related LV populations. rPinecone uses a root-to-tip directional approach to define sub-lineages within a phylogenetic tree according to SNV distance from the ancestral node. The utility of this software was demonstrated using both simulated outbreaks and real genomic data of two LV populations: a hospital outbreak of methicillin-resistant Staphylococcus aureus and endemic Salmonella Typhi from rural Cambodia. rPinecone identified the transmission branches of the hospital outbreak and geographically confined lineages in Cambodia. Sub-lineages identified by rPinecone in both analyses were phylogenetically robust. It is anticipated that rPinecone can be used to discriminate between lineages of bacteria from LV populations where other methods fail, enabling a deeper understanding of infectious disease epidemiology for public health purposes.Peer reviewe

Global Burden of Invasive Nontyphoidal Salmonella Disease, 2010

Nontyphoidal Salmonella is a major cause of bloodstream infections worldwide, and HIV-infected persons and malaria-infected and malnourished children are at increased risk for the disease. We conducted a systematic literature review to obtain age group–specific, population-based invasive nontyphoidal Salmonella (iNTS) incidence data. Data were categorized by HIV and malaria prevalence and then extrapolated by using 2010 population data. The case-fatality ratio (CFR) was determined by expert opinion consensus. We estimated that 3.4 (range 2.1–6.5) million cases of iNTS disease occur annually (overall incidence 49 cases [range 30–94] per 100,000 population). Africa, where infants, young children, and young adults are most affected, had the highest incidence (227 cases [range 152–341] per 100,000 population) and number of cases (1.9 [range 1.3–2.9] million cases). An iNTS CFR of 20% yielded 681,316 (range 415,164–1,301,520) deaths annually. iNTS disease is a major cause of illness and death globally, particularly in Africa. Improved understanding of the epidemiology of iNTS is needed

Gut mucosal colonisation with extended-spectrum beta-lactamase producing Enterobacteriaceae in sub-Saharan Africa: a systematic review and meta-analysis.

Background: Extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBL-E) threaten human health; and, in areas of sub-Saharan Africa (sSA) where carbapenems are not available, may render ESBL-E infections untreatable. Gut mucosal colonisation probably occurs before infection, making prevention of colonisation an attractive target for intervention, but the epidemiology of ESBL-E in sSA is poorly described. Objectives: Describe ESBL-E colonisation prevalence in sSA and risk factors associated with colonisation. Methods: Studies included were prospective cross-sectional or cohort studies reporting gut mucosal ESBL-E colonisation in any population in sSA. We searched PubMed and Scopus on 18 December 2018. We summarise the range of prevalence across sites and tabulated risk factors for colonisation. The protocol was registered (Prospero ID CRD42019123559). Results: From 2975 abstracts we identified 32 studies including a total of 8619 participants from a range of countries and settings. Six studies were longitudinal; no longitudinal studies followed patients beyond hospital discharge.  Prevalence varied between 5 and 84% with a median of 31%, with a relationship to setting: pooled ESBL-E colonisation in community studies was 18% (95% CI 12 to 28, 12 studies); in studies recruiting people at admission to hospital colonisation was 32% (95% CI 24 to 41% 8 studies); and for inpatients, colonisation was 55% (95% CI 49 to 60%, 7 studies). Antimicrobial use was associated with increased risk of ESBL-E colonisation, and protected water sources or water treatment by boiling may reduce risk. Conclusions: ESBL-E colonisation is common in sSA, but how people become carriers and why is not well understood. To inform the design of interventions to interrupt transmission in this setting requires longitudinal, community studies

Mathematical Modeling to Assess the Drivers of the Recent Emergence of Typhoid Fever in Blantyre, Malawi

Background. Multiyear epidemics of Salmonella enterica serovar Typhi have been reported from countries across eastern and southern Africa in recent years. In Blantyre, Malawi, a dramatic increase in typhoid fever cases has recently occurred, and may be linked to the emergence of the H58 haplotype. Strains belonging to the H58 haplotype often exhibit multidrug resistance and may have a fitness advantage relative to other Salmonella Typhi strains. Methods. To explore hypotheses for the increased number of typhoid fever cases in Blantyre, we fit a mathematical model to culture-confirmed cases of Salmonella enterica infections at Queen Elizabeth Central Hospital, Blantyre. We explored 4 hypotheses: (1) an increase in the basic reproductive number (R(0)) in response to increasing population density; (2) a decrease in the incidence of cross-immunizing infection with Salmonella Enteritidis; (3) an increase in the duration of infectiousness due to failure to respond to first-line antibiotics; and (4) an increase in the transmission rate following the emergence of the H58 haplotype. Results. Increasing population density or decreasing cross-immunity could not fully explain the observed pattern of typhoid emergence in Blantyre, whereas models allowing for an increase in the duration of infectiousness and/or the transmission rate of typhoid following the emergence of the H58 haplotype provided a good fit to the data. Conclusions. Our results suggest that an increase in the transmissibility of typhoid due to the emergence of drug resistance associated with the H58 haplotype may help to explain recent outbreaks of typhoid in Malawi and similar settings in Africa

Sequential Acquisition of T Cells and Antibodies to Nontyphoidal Salmonella in Malawian Children

Background Salmonella Typhimurium (STm) remain a prominent cause of bacteremia in sub-Saharan Africa. Complement-fixing antibodies to STm develop by 2 years of age. We hypothesized that STm-specific CD4+ T cells develop alongside this process. Methods Eighty healthy Malawian children aged 0–60 months were recruited. STm-specific CD4+ T cells producing interferon γ, tumor necrosis factor α, and interleukin 2 were quantified using intracellular cytokine staining. Antibodies to STm were measured by serum bactericidal activity (SBA) assay, and anti-STm immunoglobulin G antibodies by enzyme-linked immunosorbent assay. Results Between 2006 and 2011, STm bacteremias were detected in 449 children <5 years old. STm-specific CD4+ T cells were acquired in infancy, peaked at 14 months, and then declined. STm-specific SBA was detectable in newborns, declined in the first 8 months, and then increased to a peak at age 35 months. Acquisition of SBA correlated with acquisition of anti–STm–lipopolysaccharide (LPS) immunoglobulin G (r = 0.329 [95% confidence interval, .552–.062]; P = .01) but not anti–STm–outer membrane protein or anti–STm-flagellar protein (FliC). Conclusions Acquisition of STm-specific CD4+ T cells in early childhood is consistent with early exposure to STm or cross-reactive protein antigens priming this T-cell development. STm-specific CD4+ T cells seem insufficient to protect against invasive nontyphoidal Salmonella disease, but sequential acquisition of SBA to STm LPS is associated with a decline in its incidence

Febrile Illness Evaluation in a Broad Range of Endemicities (FIEBRE): protocol for a multisite prospective observational study of the causes of fever in Africa and Asia.

INTRODUCTION NlmCategory: BACKGROUND content: Fever commonly leads to healthcare seeking and hospital admission in sub-Saharan Africa and Asia. There is only limited guidance for clinicians managing non-malarial fevers, which often results in inappropriate treatment for patients. Furthermore, there is little evidence for estimates of disease burden, or to guide empirical therapy, control measures, resource allocation, prioritisation of clinical diagnostics or antimicrobial stewardship. The Febrile Illness Evaluation in a Broad Range of Endemicities (FIEBRE) study seeks to address these information gaps. - Label: METHODS AND ANALYSIS NlmCategory: UNASSIGNED content: FIEBRE investigates febrile illness in paediatric and adult outpatients and inpatients using standardised clinical, laboratory and social science protocols over a minimum 12-month period at five sites in sub-Saharan Africa and Southeastern and Southern Asia. Patients presenting with fever are enrolled and provide clinical data, pharyngeal swabs and a venous blood sample; selected participants also provide a urine sample. Laboratory assessments target infections that are treatable and/or preventable. Selected point-of-care tests, as well as blood and urine cultures and antimicrobial susceptibility testing, are performed on site. On day 28, patients provide a second venous blood sample for serology and information on clinical outcome. Further diagnostic assays are performed at international reference laboratories. Blood and pharyngeal samples from matched community controls enable calculation of AFs, and surveys of treatment seeking allow estimation of the incidence of common infections. Additional assays detect markers that may differentiate bacterial from non-bacterial causes of illness and/or prognosticate illness severity. Social science research on antimicrobial use will inform future recommendations for fever case management. Residual samples from participants are stored for future use. - Label: ETHICS AND DISSEMINATION NlmCategory: UNASSIGNED content: Ethics approval was obtained from all relevant institutional and national committees; written informed consent is obtained from all participants or parents/guardians. Final results will be shared with participating communities, and in open-access journals and other scientific fora. Study documents are available online (https://doi.org/10.17037/PUBS.04652739)

A qualitative study exploring health workers and patient caregivers' hand hygiene practices in a neonatal unit in Blantyre, Malawi, implications for controlling outbreaks of drug resistant infections

Background: Neonatal sepsis is responsible for a considerable burden of morbidity and mortality in sub-Saharan African countries. Outcomes from neonatal sepsis are worsening due to increasing rates of antimicrobial resistance. Sub-optimal Infection Prevention and Control (IPC) practices of health care workers and caregivers are important drivers of infection transmission. The Chatinkha Neonatal Unit at Queen Elizabeth Central Hospital, Blantyre, Malawi has experienced multiple outbreaks of neonatal sepsis, associated with drug resistant Klebsiella pneumoniae. We aimed to understand the barriers to implementation of optimal IPC focusing on hand hygiene practice. Methods: We used a qualitative research methodology to meet the study aim. Combining participant observation (PO) over a seven-month period with semi structured interviews (SSI) to provide an in-depth understanding of activities relating to hygiene and IPC existing on the ward. Results: While most staff and some caregivers, had a good understanding of ideal IPC and understood the importance of good handwashing practices, they faced substantial structural limitations, and scarce resources (both material and human) which made implementation challenging. For staff, the overwhelming numbers of patients meant the workload was often unmanageable and practicing optimal IPC was challenging. Caregivers lacked access to basic amenities, including linen and chairs, meaning that it was almost impossible for them to maintain good hand hygiene. Limited access to soap and the erratic water supply for both caregivers and healthcare workers further worsened the situation. Communication challenges between different cadres of staff and with patient caregivers meant that those handling neonates and cleaning the wards were often unaware of outbreaks of drug resistant infection. Conclusion: For IPC to be improved, interventions need to address the chronic shortages of material resources and create an enabling environment for HCWs and patient caregivers