A prospective study of bloodstream infections as cause of fever in Malawi: clinical predictors and implications for management

Examining geospatial and temporal distribution of invasive non-typhoidal Salmonella disease occurrence in sub-Saharan Africa: a systematic review and modelling study

BACKGROUND

Invasive non-typhoidal Salmonella (iNTS) disease is a significant health concern in sub-Saharan Africa. While our knowledge of a larger-scale variation is growing, understanding of the subnational variation in iNTS disease occurrence is lacking, yet crucial for targeted intervention.

METHOD

We performed a systematic review of reported occurrences of iNTS disease in sub-Saharan Africa, consulting literature from PubMed, Embase and Web of Science published since 2000. Eligibility for inclusion was not limited by study type but required that studies reported original data on human iNTS diseases based on the culture of a normally sterile site, specifying subnational locations and the year, and were available as full-text articles. We excluded studies that diagnosed iNTS disease based on clinical indications, cultures from non-sterile sites or serological testing. We estimated the probability of occurrence of iNTS disease for sub-Saharan Africa on 20 km × 20 km grids by exploring the association with geospatial covariates such as malaria, HIV, childhood growth failure, access to improved water, and sanitation using a boosted regression tree.

RESULTS

We identified 130 unique references reporting human iNTS disease in 21 countries published from 2000 through 2020. The estimated probability of iNTS occurrence grids showed significant spatial heterogeneity at all levels (20 km × 20 km grids, subnational, country and subregional levels) and temporal heterogeneity by year. For 2020, the probability of occurrence was higher in Middle Africa (0.34, 95% CI: 0.25 to 0.46), followed by Western Africa (0.33, 95% CI: 0.23 to 0.44), Eastern Africa (0.24, 95% CI: 0.17 to 0.33) and Southern Africa (0.08, 95% CI: 0.03 to 0.11). Temporal heterogeneity indicated that the probability of occurrence increased between 2000 and 2020 in countries such as the Republic of the Congo (0.05 to 0.59) and Democratic Republic of the Congo (0.10 to 0.48) whereas it decreased in countries such as Uganda (0.65 to 0.23) or Zimbabwe (0.61 to 0.37).

CONCLUSION

The iNTS disease occurrence varied greatly across sub-Saharan Africa, with certain regions being disproportionately affected. Exploring regions at high risk for iNTS disease, despite the limitations in our data, may inform focused resource allocation. This targeted approach may enhance efforts to combat iNTS disease in more affected areas.

The role of tissue resident memory CD4 T cells in Salmonella infection: Implications for future vaccines

Salmonella infections cause a wide range of intestinal and systemic disease that affects global human health. While some vaccines are available, they do not mitigate the impact of Salmonella on endemic areas. Research using Salmonella mouse models has revealed the important role of CD4 T cells and antibody in the development of protective immunity against Salmonella infection. Recent work points to a critical role for hepatic tissue-resident memory lymphocytes in naturally acquired immunity to systemic infection. Thus, understanding the genesis and function of this Salmonella-specific population is an important objective and is the primary focus of this review. Greater understanding of how these memory lymphocytes contribute to bacterial elimination could suggest new approaches to vaccination against an important human pathogen.

The characteristics of bacteremia among patients with acute febrile illness requiring hospitalization in Indonesia

Blood culturing remains the "gold standard" for bloodstream infection (BSI) diagnosis, but the method is inaccessible to many developing countries due to high costs and insufficient resources. To better understand the utility of blood cultures among patients in Indonesia, a country where blood cultures are not routinely performed, we evaluated data from a previous cohort study that included blood cultures for all participants. An acute febrile illness study was conducted from July 2013 to June 2016 at eight major hospitals in seven provincial capitals in Indonesia. All participants presented with a fever, and two-sided aerobic blood cultures were performed within 48 hours of hospital admission. Positive cultures were further assessed for antimicrobial resistance (AMR) patterns. Specimens from participants with negative culture results were screened by advanced molecular and serological methods for evidence of causal pathogens. Blood cultures were performed for 1,459 of 1,464 participants, and the 70.6% (1,030) participants that were negative by dengue NS1 antigen test were included in further analysis. Bacteremia was observed in 8.9% (92) participants, with the most frequent pathogens being Salmonella enterica serovar Typhi (41) and Paratyphi A (10), Escherichia coli (14), and Staphylococcus aureus (10). Two S. Paratyphi A cases had evidence of AMR, and several E. coli cases were multidrug resistant (42.9%, 6/14) or monoresistant (14.3%, 2/14). Culture contamination was observed in 3.6% (37) cases. Molecular and serological assays identified etiological agents in participants having negative cultures, with 23.1% to 90% of cases being missed by blood cultures. Blood cultures are a valuable diagnostic tool for hospitalized patients presenting with fever. In Indonesia, pre-screening patients for the most common viral infections, such as dengue, influenza, and chikungunya viruses, would maximize the benefit to the patient while also conserving resources. Blood cultures should also be supplemented with advanced laboratory tests when available.

A systematic review and meta-analysis of the aetiological agents of non-malarial febrile illnesses in Africa

Background

The awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades. Therefore, we undertook a systematic literature review and meta-analysis of causative agents of non-malarial fevers on the African continent.

Methodology

We searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of Science databases to identify aetiologic agents that had been reported and to determine summary estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever patients.

Findings

A total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible. A wide array of aetiologic agents were described with considerable regional differences among the leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest proportion. The summary estimates from the meta-analysis were low for most of the agents. This may have resulted from a true low prevalence of the agents, the failure to test for many agents or the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and population variables showed that diagnostic methods determined the PMr estimates of typhoidal Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of Haemophilus spp. infections.

Conclusion

The small number of epidemiological studies and the variety of NMFI agents on the African continent emphasizes the need for harmonized studies with larger sample sizes. In particular, diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public health strategies.

Previous systematic reviews have highlighted the research priorities of causative agents for non-malarial febrile illnesses by counting the number of publications attributed to an agent. However, proportional morbidity rates are calculated by dividing the number of cases with a specific disease (numerator) by the total number of diagnosed fever cases (denominator) and are better indicators of the relative importance of aetiological agents in a population. Therefore, we present the leading causes of non-malarial febrile illnesses in African patients in both healthcare and community settings. Preference is given to HIV-negative patients when data could be found. We also determined summary estimates of Brucella spp., Chikungunya virus, Dengue virus, Haemophilus spp., Klebsiella spp., Leptospira spp., non-typhoidal Salmonella spp., typhoidal Salmonella spp., Staphylococcus spp., and Streptococcus spp.

The wide array of aetiological agents causing febrile illnesses on the African continent does not only complicate malaria control programs but may also hamper response to epidemic and pandemic illnesses such as Ebola and COVID-19. The harmonisation of diagnostics and study designs will reduce between-study differences, which may result in better estimates of disease burden on the continent and in the different African regions. This information is important for Pan-African surveillance and control efforts.

Prevalence, distribution and antimicrobial susceptibility pattern of bacterial isolates from a tertiary Hospital in Malawi

Background

Bacterial infections are a significant cause of sickness and death in sub-Saharan Africa. This study aimed at establishing the prevalence, distribution and antimicrobial susceptibility pattern of major bacterial isolates from patients accessing medical care at a tertiary hospital in Malawi.

Methods

We retrospectively reviewed bacteria culture and antimicrobial susceptibility records for 4617 patients from 2002 to 2014 at Mzuzu Central Hospital (MCH). No inclusion and exclusion criteria were followed. Data was analysed using excel (Microsoft office, USA) and GraphPad prism 7 software programs.

Results

The most prevalent isolates were S. aureus (34.7%, n = 783), Klebsiella species (17.4%, n = 393) and Proteus species (11.4%, n = 256). Most microorganisms were isolated from adults (88.3%, n = 3889) and pus was the main source (69.3%, n = 1224). S. pneumoniae was predominantly isolated from cerebrospinal fluid (60.3%, n = 44) largely collected from children (88.2%, n = 64). Overall, most bacteria exhibited high resistance to all regularly used antimicrobials excluding ciprofloxacin.

Conclusions

Our report demonstrates an increase in bacterial infection burden in sites other than blood stream and subsequent increase in prevalence of antimicrobial resistance for all major isolates. Creating an epidemiological survey unit at MCH will be essential to help inform better treatment and management options for patients with bacterial infections.

Bacteraemia, Malaria, and Case Fatality Among Children Hospitalized With Fever in Dar es Salaam, Tanzania

Background

Febrile illness is the commonest cause of hospitalization in children <5 years in sub-Saharan Africa, and bacterial bloodstream infections and malaria are major causes of death.

Methods

From March 2017 to July 2018, we enrolled 2,226 children aged 0–5 years hospitalized due to fever in four major public hospitals of Dar es Salaam, namely, Amana, Temeke, and Mwananyamala Regional Hospitals and Muhimbili National Hospital. We recorded social demographic and clinical data, and we performed blood-culture and HIV-antibody testing. We used qPCR to quantify Plasmodium falciparum parasitaemia and Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) to identify bacterial isolates. Disk diffusion method was used for antimicrobial susceptibility testing.

Results

Nineteen percent of the children (426/2,226) had pathogens detected from blood. Eleven percent (236/2,226) of the children had bacteraemia/fungaemia and 10% (204/2,063) had P. falciparum malaria. Ten children had concomitant malaria and bacteraemia. Gram-negative bacteria (64%) were more frequent than Gram-positive (32%) and fungi (4%). Over 50% of Gram-negative bacteria were extended-spectrum beta-lactamase (ESBL) producers and multidrug resistant. Methicillin resistant Staphylococcus aureus (MRSA) was found in 11/42 (26.2%). The most severe form of clinical malaria was associated with high parasitaemia (>four million genomes/μL) of P. falciparum in plasma. Overall, in-hospital death was 4% (89/2,146), and it was higher in children with bacteraemia (8%, 18/227) than malaria (2%, 4/194, p = 0.007). Risk factors for death were bacteraemia (p = 0.03), unconsciousness at admission (p < 0.001), and admission at a tertiary hospital (p = 0.003).

Conclusion

Compared to previous studies in this region, our study showed a reduction in malaria prevalence, a decrease in in-hospital mortality, and an increase in antimicrobial resistance (AMR) including ESBLs and multidrug resistance. An increase of AMR highlights the importance of continued strengthening of diagnostic capability and antimicrobial stewardship programs. We also found malaria and bacteraemia contributed equally in causing febrile illness, but bacteraemia caused higher in-hospital death. The most severe form of clinical malaria was associated with P. falciparum parasitaemia.

Presentation and outcome of suspected sepsis in a high-HIV burden, high antiretroviral coverage setting

Objective:

To define sepsis syndromes in high-HIV burden settings in the antiretroviral therapy (ART) era. Methods: We characterized a prospective cohort of adults presenting to a tertiary emergency department in Harare, Zimbabwe with suspected community-acquired sepsis using blood and urine cultures, urine tuberculosis lipoarabinomannan (TB LAM), and serum cryptococcal antigen (CrAg) testing. The primary outcome was 30-day all-cause mortality.

Results:

Of 142 patients enrolled 68% (n = 96/142, 95% confidence interval (CI) [60–75%]) were HIV-positive, 41% (n = 39/96, 95% CI [31–50%]) of whom were ART-naïve. Among HIV-positive patients, both opportunistic pathogens (TB LAM-positivity, 36%, 95% CI [24–48%]; CrAg-positivity, 15%, 95% CI [7–23%]) and severe non-AIDS infections (S. pneumoniae urine antigen-positivity 12%, 95% CI [4–20%]; bacteraemia 17% (n = 16/96, 95% CI [9–24%]), of which 56% (n = 9/16, 95% CI [30–80%]) were gram-negative organisms) were common. Klebsiella pneumoniae recovered from blood and urine was uniformly resistant to ceftriaxone, as were most Escherichia coli isolates. Acknowledging the power limitations of our study, we conclude that relative to HIV-negative patients, HIV-positive patients had modestly higher 30-day mortality (adjusted hazard ratio (HR) 1.88, 95% CI [0.78–4.55]; p = 0.16, and 3.59, 95% CI [1.27–10.16], p = 0.02) among those with and without viral suppression, respectively.

Conclusion:

Rapid point-of-care assays provide substantial clinically actionable information in the setting of suspected sepsis, even in areas with high ART coverage. Antimicrobial resistance to first-line antibiotics in high burden settings is a growing threat.

A Systematic Review and Meta-analysis of the Prevalence of Community-Onset Bloodstream Infections among Hospitalized Patients in Africa and Asia

Community-onset bloodstream infections (CO-BSI) are major causes of severe febrile illness and death worldwide. In light of new data and the growing problem of antimicrobial resistance (AMR) among pathogens causing BSI, we undertook a systematic review of hospital-based studies of CO-BSI among patients hospitalized with fever.

Community-onset bloodstream infections (CO-BSI) are major causes of severe febrile illness and death worldwide. In light of new data and the growing problem of antimicrobial resistance (AMR) among pathogens causing BSI, we undertook a systematic review of hospital-based studies of CO-BSI among patients hospitalized with fever. Without restriction to language or country, we searched PubMed, Web of Science, and Scopus for prospective hospital-based studies of culture-confirmed CO-BSI among febrile inpatients. We determined by study the prevalence of BSI among participants, the pathogens responsible for BSI, and the antimicrobial susceptibility patterns of pathogens causing BSI, according to place and time. Thirty-four (77.3%) of 44 eligible studies recruited 29,022 participants in Africa and Asia combined. Among participants in these two regions, the median prevalence of BSI was 12.5% (range, 2.0 to 48.4%); of 3,220 pathogens isolated, 1,119 (34.8%) were Salmonella enterica, 425 (13.2%) Streptococcus pneumoniae, and 282 (8.8%) Escherichia coli. Antimicrobial susceptibility testing was reported in 16 (36.4%) studies. When isolates collected prior to 2008 were compared to those collected in the period of 2008 through 2018, the proportions of typhoidal Salmonella and Staphylococcus aureus isolates resistant to several clinically relevant antimicrobials increased over time, while S. pneumoniae susceptibility was stable. CO-BSI remain a major cause of severe febrile illness among hospitalized patients in Africa and Asia, with S. enterica, S. pneumoniae, and E. coli predominating. There is a concerning increase in AMR among serious infections caused by community-onset pathogens. Ongoing surveillance is needed to inform empirical management and strategies to control AMR.

Using hospital-based studies of community-onset bloodstream infections to make inferences about typhoid fever incidence

Objectives

Hospital-based studies of community-onset bloodstream infections (CO-BSI) are less resource-intensive to carry out than population-based incidence studies. We examined several metrics capturing the potential role of Salmonella Typhi as a cause of CO-BSI for making inferences about incidence.

Methods

We systematically reviewed three databases for hospital-based studies of CO-BSI. We determined, by study, the prevalence and rank order of Salmonella among pathogenic bloodstream isolates, and the prevalence ratio of Salmonella Typhi to Escherichia coli (S:E ratio). We then describe these hospital-based study metrics in relation to population-based typhoid fever incidence data from a separate systematic review.

Results

Forty-four studies met the inclusion criteria, of which 23 (52.3%) isolated Salmonella Typhi at least once. Among studies isolating Salmonella Typhi, the median (interquartile range) prevalence and rank order of Salmonella Typhi compared to other pathogens isolated in BSI was 8.3% (3.2–37.9%) and 3 (1–6), respectively. The median (interquartile range) S:E ratio was 1.0 (0.4–3.0). With respect to incidence, in Pemba Island, Tanzania, prevalence, rank order, S:E ratio, and incidence was 64.8%, 1, 9.2 and 110 cases per 100 000, respectively, and in Boulkiemdé, Burkina Faso, was 13.3%, 3, 2.3 and 249 cases per 100 000.

Conclusions

We describe considerable variation in place and time for Salmonella Typhi prevalence, rank order, and S:E ratio among hospital-based studies of CO-BSI. Data from simultaneous typhoid prevalence and incidence studies are limited. We propose that hospital-based study metrics warrant evaluation for making inference about typhoid incidence and as covariates in typhoid incidence models.

Invasive Nontyphoidal Salmonella Disease in Africa

Nontyphoidal salmonellae (NTS) are a major cause of invasive (iNTS) disease in sub-Saharan Africa, manifesting as bacteremia and meningitis. Available epidemiological data indicate that iNTS disease is endemic in much of the region. Antimicrobial resistance is common and case fatality rates are high. There are well-characterized clinical associations with iNTS disease, including young age, HIV infection, malaria, malnutrition, anemia, and sickle cell disease. However, the clinical presentation of iNTS disease is often with fever alone, so clinical diagnosis is impossible without blood culture confirmation. No vaccine is currently available, making this a priority area for global health research. Over the past ten years, it has emerged that iNTS disease in Africa is caused by distinct pathovars of Salmonella Typhimurium, belonging to sequence type ST313, and Salmonella Enteritidis. These are characterized by genome degradation and appear to be adapting to an invasive lifestyle. Investigation of rare patients with primary immunodeficiencies has suggested a key role for interferon gamma-mediated immunity in host defense against NTS. This concept has been supported by recent population-based host genetic studies in African children. In contrast, immunoepidemiological studies from Africa indicate an important role for antibody for protective immunity, supporting the development of antibody-inducing vaccines against iNTS disease. With candidate O-antigen-based vaccines due to enter clinical trials in the near future, research efforts should focus on understanding the relative contributions of antibody and cell-mediated immunity to protection against iNTS disease in humans.

Prognostic value of quickSOFA as a predictor of 28-day mortality among febrile adult patients presenting to emergency departments in Dar es Salaam, Tanzania

Background

Quick Sequential Organ Failure Assessment (qSOFA) is a three-item clinical instrument for bedside identification of sepsis patients at risk of poor outcome. qSOFA could be a valuable triage tool in emergency departments of low-income countries, yet its performance in resource-limited settings remains unknown. The prognostic accuracy of qSOFA for 28-day all-cause mortality in febrile adults treated at the EDs in a low-income country was evaluated.

Methods

Retrospective analysis of a prospective cohort study of consecutive patients (≥18 years) with fever (tympanic temperature ≥38°C and fever ≤7 days) who presented between July 2013 and May 2014 at four emergency departments in Dar es Salaam, Tanzania. Medical history, clinical examination, laboratory and microbiological data were collected to document the cause of fever. Variables for the previous and new sepsis criteria were collected at inclusion and qSOFA, SOFA and SIRS were measured at inclusion. Patients were followed up by phone at day 28. The performance (sensitivity, specificity and area under the receiver operating curve [AUROC]) of qSOFA (score ≥2), SOFA (increase of ≥2 points) and SIRS (≥2 criteria) as predictors of 28-day all-cause mortality was evaluated.

Results

Among the 519 patients (median age: 30 years) included in the analysis, 47% were female and 25% were HIV positive. Overall, 85% had a microbiologically and/or clinically documented infection and 15% a fever of unknown origin. The most common site and causes of infections were the respiratory tract (43%), dengue (26%), malaria (6%) and typhoid fever (5%). Twenty-eight-day all-cause mortality was 6%: 3% for patients with a qSOFA <2 and 24% for those with a score ≥2 (absolute difference, 21%; 95% CI 12%-31%). The prognostic accuracy of qSOFA (AUROC 0.80, 95% CI 0.73–0.87) for 28-day mortality was similar to SOFA (AUROC 0.79, 0.71–0.87; p = 0.1) and better than SIRS (AUROC 0.61, 0.52–0.71; p<0.001).

Conclusions

Among patients with fever at emergency departments in Tanzania, qSOFA had a prognostic accuracy for 28-day mortality comparable to SOFA and superior to SIRS. These results support the use of qSOFA as a triage tool to identify patients with sepsis and at risk of poor outcome in resource-limited countries.

Trial registration

Clinicaltrials.gov Identifier: NCT01947075

HIV-malaria interactions in North-East India: A prospective cohort study

Background & objectives:

The interactions between HIV and malaria co-infection have been shown to influence each other in their clinical outcomes in Sub-Saharan Africa. This study was carried out in the two States of north east India endemic for both HIV and malaria infections, to study the interactions between the two diseases in the HIV-infected population.

Methods:

In this prospective study, a total of 333 HIV-infected individuals were followed up for a period of 6-18 months in Mizoram and Manipur during 2010-2011. The study assessed the changes in viral load and also the therapeutic efficacy of artesunate plus sulphadoxine-pyrimethamine (AS+SP) combination therapy in HIV-infected and HIV-uninfected individuals with Plasmodium falciparum malaria.

Results:

Viral load in HIV-infected malaria patients on day zero (D0) ranged from 1110 to 147,000 copies/ml. The log transformation of the geometric means of HIV viral loads revealed no significant difference on different days of follow up. There was 100 per cent adequate clinical and parasitological response (ACPR) after treating with artemisinin based combination therapy (ACT) both in HIV-infected and HIV-uninfected P. falciparum-positive individuals. Similarly, chloroquine showed 100 per cent ACPR in P. vivax HIV-infected individuals.

Interpretation & conclusion:

The study showed no significant increase in HIV viral load in malaria cases. All HIV-infected and HIV-uninfected P. falciparum malaria-positive cases responded to the treatment with 100 per cent ACPR.

Prevalence and factors associated with Mycobacteremia and mortality among febrile HIV infected patients in Mwanza, Tanzania

OBJECTIVES

This study investigated the prevalence and factors associated with mycobacteremia and mortality among febrile HIV infected patients in developing countries.

METHODS

A hospital based cross-sectional study was conducted among febrile HIV patients admitted at Bugando Medical centre and Sekou Toure hospital between November 2016 and March 2017. Blood culture was done on BACTEC Myco/F Lytic bottles. Clinical and demographic data were collected using a pre-tested data collection tool.

RESULTS

A total of 154 patients with the mean age of 41.5±12.2 were enrolled. Females formed the majority, 93 (60%) of the study participants. The prevalence of Mycobacteremia was 3.3% while that of other bacteria was 8.4%. Age (p=0.03), recent HIV diagnosis (p=0.005), not taking HAART (p=0.031) and low CD4+ count (p=0.002) were significantly associated with Mycobacteremia. Factors significantly associated with 14-day in-hospital mortality were advanced HIV infection (p<0.001), poor ART adherence (p<0.001), low CD4+ (p=0.0002) and Mycobacteremia (p=0.007).

CONCLUSION

The prevalence of Mycobacteremia was low; however, it was significantly associated with mortality. Mycobacteremia should be suspected in high risk febrile HIV infected individuals followed by early appropriate treatment in order to reduce associated morbidity and mortality.

Clinical bacteriology in low-resource settings: today's solutions

Low-resource settings are disproportionately burdened by infectious diseases and antimicrobial resistance. Good quality clinical bacteriology through a well functioning reference laboratory network is necessary for effective resistance control, but low-resource settings face infrastructural, technical, and behavioural challenges in the implementation of clinical bacteriology. In this Personal View, we explore what constitutes successful implementation of clinical bacteriology in low-resource settings and describe a framework for implementation that is suitable for general referral hospitals in low-income and middle-income countries with a moderate infrastructure. Most microbiological techniques and equipment are not developed for the specific needs of such settings. Pending the arrival of a new generation diagnostics for these settings, we suggest focus on improving, adapting, and implementing conventional, culture-based techniques. Priorities in low-resource settings include harmonised, quality assured, and tropicalised equipment, consumables, and techniques, and rationalised bacterial identification and testing for antimicrobial resistance. Diagnostics should be integrated into clinical care and patient management; clinically relevant specimens must be appropriately selected and prioritised. Open-access training materials and information management tools should be developed. Also important is the need for onsite validation and field adoption of diagnostics in low-resource settings, with considerable shortening of the time between development and implementation of diagnostics. We argue that the implementation of clinical bacteriology in low-resource settings improves patient management, provides valuable surveillance for local antibiotic treatment guidelines and national policies, and supports containment of antimicrobial resistance and the prevention and control of hospital-acquired infections.

Predictive value of C-reactive protein for tuberculosis, bloodstream infection or death among HIV-infected individuals with chronic, non-specific symptoms and negative sputum smear microscopy

BACKGROUND

C-reactive protein (CRP) is an inflammatory biomarker that may identify patients at risk of infections or death. Mortality among HIV-infected persons commencing antiretroviral therapy (ART) is often attributed to tuberculosis (TB) or bloodstream infections (BSI).

METHODS

In two district hospitals in southern Malawi, we recruited HIV-infected adults with one or more unexplained symptoms present for at least one month (weight loss, fever or diarrhoea) and negative expectorated sputum microscopy for TB. CRP determination for 452 of 469 (96%) participants at study enrolment was analysed for associations with TB, BSI or death to 120 days post-enrolment.

RESULTS

Baseline CRP was significantly elevated among patients with confirmed or probable TB (52), BSI (50) or death (60) compared to those with no identified infection who survived at least 120 days (269). A CRP value of >10 mg/L was associated with confirmed or probable TB (adjusted odds ratio 5.7; 95% CI 2.6, 14.3; 87% sensitivity) or death by 30 days (adjusted odds ratio 9.2; 95% CI 2.2, 55.1; 88% sensitivity). CRP was independently associated with TB, BSI or death, but the prediction of these endpoints was enhanced by including haemoglobin (all outcomes), CD4 count (BSI, death) and whether ART was started (death) in logistic regression models.

CONCLUSION

High CRP at the time of ART initiation is associated with TB, BSI and early mortality and so has potential utility for stratifying patients for intensified clinical and laboratory investigation and follow-up. They may also be considered for empirical treatment of opportunistic infections including TB.

The effects of iron fortification and supplementation on the gut microbiome and diarrhea in infants and children: a review

In infants and young children in Sub-Saharan Africa, iron-deficiency anemia (IDA) is common, and many complementary foods are low in bioavailable iron. In-home fortification of complementary foods using iron-containing micronutrient powders (MNPs) and oral iron supplementation are both effective strategies to increase iron intakes and reduce IDA at this age. However, these interventions produce large increases in colonic iron because the absorption of their high iron dose (≥12.5 mg) is typically <20%. We reviewed studies in infants and young children on the effects of iron supplements and iron fortification with MNPs on the gut microbiome and diarrhea. Iron-containing MNPs and iron supplements can modestly increase diarrhea risk, and in vitro and in vivo studies have suggested that this occurs because increases in colonic iron adversely affect the gut microbiome in that they decrease abundances of beneficial barrier commensal gut bacteria (e.g., bifidobacteria and lactobacilli) and increase the abundance of enterobacteria including entropathogenic Escherichia coli These changes are associated with increased gut inflammation. Therefore, safer formulations of iron-containing supplements and MNPs are needed. To improve MNP safety, the iron dose of these formulations should be reduced while maximizing absorption to retain efficacy. Also, the addition of prebiotics to MNPs is a promising approach to mitigate the adverse effects of iron on the infant gut.

Development of ELISAs for diagnosis of acute typhoid fever in Nigerian children

Improved serodiagnostic tests for typhoid fever (TF) are needed for surveillance, to facilitate patient management, curb antibiotic resistance, and inform public health programs. To address this need, IgA, IgM and IgG ELISAs using Salmonella enterica serovar Typhi (S. Typhi) lipopolysaccharide (LPS) and hemolysin E (t1477) protein were conducted on 86 Nigerian pediatric TF and 29 non-typhoidal Salmonella (NTS) cases, 178 culture-negative febrile cases, 28 "other" (i.e., non-Salmonella) pediatric infections, and 48 healthy Nigerian children. The best discrimination was achieved between TF and healthy children. LPS-specific IgA and IgM provided receiver operator characteristic areas under the curve (ROC AUC) values of 0.963 and 0.968, respectively, and 0.978 for IgA+M combined. Similar performance was achieved with t1477-specific IgA and IgM (0.968 and 0.968, respectively; 0.976 combined). IgG against LPS and t1477 was less accurate for discriminating these groups, possibly as a consequence of previous exposure, although ROC AUC values were still high (0.928 and 0.932, respectively). Importantly, discrimination between TF and children with other infections was maintained by LPS-specific IgA and IgM (AUC = 0.903 and 0.934, respectively; 0.938 combined), and slightly reduced for IgG (0.909), while t1477-specific IgG performed best (0.914). A similar pattern was seen when comparing TF with other infections from outside Nigeria. The t1477 may be recognized by cross-reactive antibodies from other acute infections, although a robust IgG response may provide some diagnostic utility in populations where incidence of other infections is low, such as in children. The data are consistent with IgA and IgM against S. Typhi LPS being specific markers of acute TF.

Bloodstream infections in HIV-infected patients

In the combined antiretroviral therapy era, HIV-infected patients remain a vulnerable population for the onset of bloodstream infections (BSI). Worldwide, nontyphoid salmonellae, Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus and coagulase negative staphylococci are the most important pathogens. Intravenous catheter associated infection, skin-soft tissue infection and endocarditis are associated with Gram-positive bacteremia. Among the Gram-negative, nontyphoidal Salmonella have been previously correlated to sepsis. Other causes of BSI in HIV-infected patients are mycobacteria and fungi. Mycobacteria constitute a major cause of BSI in limited resource countries. Fungal BSI are not frequent and among them Cryptococcus neoformans is the most common life-threatening infection. The degree of immunosuppression remains the key prognostic factor leading to the development of BSI.

A Systematic Review of the Incidence, Risk Factors and Case Fatality Rates of Invasive Nontyphoidal Salmonella (iNTS) Disease in Africa (1966 to 2014)

This study systematically reviews the literature on the occurrence, incidence and case fatality rate (CFR) of invasive nontyphoidal Salmonella (iNTS) disease in Africa from 1966 to 2014. Data on the burden of iNTS disease in Africa are sparse and generally have not been aggregated, making it difficult to describe the epidemiology that is needed to inform the development and implementation of effective prevention and control policies. This study involved a comprehensive search of PubMed and Embase databases. It documents the geographical spread of iNTS disease over time in Africa, and describes its reported incidence, risk factors and CFR. We found that Nontyphoidal Salmonella (NTS) have been reported as a cause of bacteraemia in 33 out of 54 African countries, spanning the five geographical regions of Africa, and especially in sub-Saharan Africa since 1966. Our review indicates that NTS have been responsible for up to 39% of community acquired blood stream infections in sub-Saharan Africa with an average CFR of 19%. Salmonella Typhimurium and Enteritidis are the major serovars implicated and together have been responsible for 91%% of the cases of iNTS disease, (where serotype was determined), reported in Africa. The study confirms that iNTS disease is more prevalent amongst Human Immunodeficiency Virus (HIV)-infected individuals, infants, and young children with malaria, anaemia and malnutrition. In conclusion, iNTS disease is a substantial cause of community-acquired bacteraemia in Africa. Given the high morbidity and mortality of iNTS disease in Africa, it is important to develop effective prevention and control strategies including vaccination.

Etiology and clinical features of 229 cases of bloodstream infection among Chinese HIV/AIDS patients: a retrospective cross-sectional study

Bloodstream infections (BSIs) are prevalent among people living with HIV/AIDS. The etiology varies in different regions and different periods. We aimed to survey the etiological and clinical features of BSIs in HIV patients in mainland China. We assessed all HIV patients with a positive blood culture in a Chinese teaching hospital from September 2009 through December 2014. We excluded those with specimens likely to have been contaminated. We used Pearson's chi-squared test to measure the differences in characteristics among subgroups of different pathogens. Among 2442 Chinese HIV-seropositive inpatients, 229 (9.38 %) experienced BSIs. The most common pathogens detected included Cryptococcus neoformans (22.7 %), Penicillium marneffei (18.8 %), Mycobacterium tuberculosis (15.3 %), and non-tuberculous mycobacterium (14.8 %). 30/229 (13.1 %) HIV patients with BSIs had a poor prognosis. BSIs are prevalent in hospitalized patients with HIV/AIDS in China. Fungi and mycobacteria are the predominant pathogens.

Management of severe non-TB bacterial infection in HIV-infected adults

Despite widespread antiretroviral therapy use, severe bacterial infections (SBI) in HIV-infected adults continue to cause significant morbidity and mortality globally. Four main pathogens account for the majority of documented SBI: Streptococcus pneumoniae, non-typhoidal strains of Salmonella enterica, Escherichia coli and Staphylococcus aureus. The epidemiology of SBI is dynamic, both in developing countries where, despite dramatic successes in antiretroviral therapy, coverage is far from complete, and in settings in both resource-poor and resource-rich countries where antiretroviral therapy failure is becoming increasingly common. Throughout the world, this complexity is further compounded by rapidly emerging antimicrobial resistance, making management of SBI very challenging in these vulnerable patients. We review the causes and treatment of SBI in HIV-infected people and discuss future developments in this field.

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.

Differences in Clinical and Laboratory Findings between Group D and Non-Group D Non-Typhoidal Salmonella Gastroenteritis in Children

PURPOSE

To investigate the differences in clinical features and laboratory findings between group D and non-group D non-typhoidal Salmonella (NTS) gastroenteritis in children.

METHODS

A retrospective chart review of children diagnosed with NTS confirmed by culture study was performed. The clinical features and laboratory findings of group D and non-group D NTS were compared.

RESULTS

From 2003 to 2012, 75 cases were diagnosed as NTS at our center. The number of group D and non-group D patients was 45 and 30, respectively. The mean age was higher in group D than in non-group D patients (5.1 years vs. 3.4 years, p=0.038). Headaches were more frequently observed (p=0.046) and hematochezia was less frequently observed (p=0.017) in group D than in non-group D NTS gastroenteritis patients. A positive Widal test result was observed in 53.3% of group D and 6.7% of non-group D NTS cases (O-titer, p=0.030; H-titer, p=0.039). There were no differences in white blood cell counts, level of C-reactive protein and rate of antimicrobial resistance between group D and non-group D cases.

CONCLUSION

The more severe clinical features such as headache, fever, and higher Widal titers were found to be indicative of group D NTS gastroenteritis. Additionally, group D NTS gastroenteritis was more commonly found in older patients. Therefore, old age, fever, headache, and a positive Widal test are more indicative of group D NTS than non-group D NTS gastroenteritis. Pathophysiological mechanisms may differ across serologic groups.

Rapid emergence of multidrug resistant, H58-lineage Salmonella typhi in Blantyre, Malawi

INTRODUCTION

Between 1998 and 2010, S. Typhi was an uncommon cause of bloodstream infection (BSI) in Blantyre, Malawi and it was usually susceptible to first-line antimicrobial therapy. In 2011 an increase in a multidrug resistant (MDR) strain was detected through routine bacteriological surveillance conducted at Queen Elizabeth Central Hospital (QECH).

METHODS

Longitudinal trends in culture-confirmed Typhoid admissions at QECH were described between 1998-2014. A retrospective review of patient cases notes was conducted, focusing on clinical presentation, prevalence of HIV and case-fatality. Isolates of S. Typhi were sequenced and the phylogeny of Typhoid in Blantyre was reconstructed and placed in a global context.

RESULTS

Between 1998-2010, there were a mean of 14 microbiological diagnoses of Typhoid/year at QECH, of which 6.8% were MDR. This increased to 67 in 2011 and 782 in 2014 at which time 97% were MDR. The disease predominantly affected children and young adults (median age 11 [IQR 6-21] in 2014). The prevalence of HIV in adult patients was 16.7% [8/48], similar to that of the general population (17.8%). Overall, the case fatality rate was 2.5% (3/94). Complications included anaemia, myocarditis, pneumonia and intestinal perforation. 112 isolates were sequenced and the phylogeny demonstrated the introduction and clonal expansion of the H58 lineage of S. Typhi.

CONCLUSIONS

Since 2011, there has been a rapid increase in the incidence of multidrug resistant, H58-lineage Typhoid in Blantyre. This is one of a number of reports of the re-emergence of Typhoid in Southern and Eastern Africa. There is an urgent need to understand the reservoirs and transmission of disease and how to arrest this regional increase.

Sepsis carries a high mortality among hospitalised adults in Malawi in the era of antiretroviral therapy scale-up: a longitudinal cohort study

OBJECTIVE

To assess mortality risk among adults presenting to an African teaching hospital with sepsis and severe sepsis in a setting of high HIV prevalence and widespread ART uptake.

METHODS

Prospective cohort study of adults (age ≥16 years) admitted with clinical suspicion of severe infection between November 2008 and January 2009 to Queen Elizabeth Central Hospital, a 1250-bed government-funded hospital in Blantyre, Malawi. Demographic, clinical and laboratory information, including blood and cerebrospinal fluid cultures were obtained on admission.

RESULTS

Data from 213 patients (181 with sepsis and 32 with severe sepsis; M:F = 2:3) were analysed. 161 (75.6%) patients were HIV-positive. Overall mortality was 22%, rising to 50% amongst patients with severe sepsis. The mortality of all sepsis patients commenced on antiretroviral therapy (ART) within 90 days was 11/28 (39.3%) compared with 7/42 (16.7%) among all sepsis patients on ART for greater than 90 days (p = 0.050). Independent associations with death were hypoxia (OR = 2.4; 95% CI, 1.1-5.1) and systolic hypotension (OR 7.0; 95% CI: 2.4-20.4).

CONCLUSIONS

Sepsis and severe sepsis carry high mortality among hospitalised adults in Malawi. Measures to reduce this, including early identification and targeted intervention in high-risk patients, especially HIV-positive individuals recently commenced on ART, are urgently required.

Simplified severe sepsis protocol: a randomized controlled trial of modified early goal-directed therapy in Zambia

OBJECTIVE

To assess the efficacy of a simple, goal-directed sepsis treatment protocol for reducing mortality in patients with severe sepsis in Zambia.

DESIGN

Single-center nonblinded randomized controlled trial.

SETTING

Emergency department, ICU, and medical wards of the national referral hospital in Lusaka, Zambia.

PATIENTS

One hundred twelve patients enrolled within 24 hours of admission with severe sepsis, defined as systemic inflammatory response syndrome with suspected infection and organ dysfunction

INTERVENTIONS

: Simplified Severe Sepsis Protocol consisting of up to 4 L of IV fluids within 6 hours, guided by jugular venous pressure assessment, and dopamine and/or blood transfusion in selected patients. Control group was managed as usual care. Blood cultures were collected and early antibiotics administered for both arms.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was in-hospital all-cause mortality. One hundred nine patients were included in the final analysis and 88 patients (80.7%) were HIV positive. Pulmonary infections were the most common source of sepsis. In-hospital mortality rate was 64.2% in the intervention group and 60.7% in the control group (relative risk, 1.05; 95% CI, 0.79-1.41). Mycobacterium tuberculosis complex was isolated from 31 of 82 HIV-positive patients (37.8%) with available mycobacterial blood culture results. Patients in Simplified Severe Sepsis Protocol received significantly more IV fluids in the first 6 hours (2.7 L vs 1.7 L, p = 0.002). The study was stopped early because of high mortality rate among patients with hypoxemic respiratory failure in the intervention arm (8/8, 100%) compared with the control arm (7/10, 70%; relative risk, 1.43; 95% CI, 0.95-2.14).

CONCLUSION

Factors other than tissue hypoperfusion probably account for much of the end-organ dysfunction in African patients with severe sepsis. Studies of fluid-based interventions should utilize inclusion criteria to accurately capture patients with hypovolemia and tissue hypoperfusion who are most likely to benefit from fluids. Exclusion of patients with severe respiratory distress should be considered when ventilatory support is not readily available.

The effect of HIV infection on the host response to bacterial sepsis

Bacterial sepsis is an important cause of morbidity and mortality in patients with HIV. HIV causes increased susceptibility to invasive infections and affects sepsis pathogenesis caused by pre-existing activation and exhaustion of the immune system. We review the effect of HIV on different components of immune responses implicated in bacterial sepsis, and possible mechanisms underlying the increased risk of invasive bacterial infections. We focus on pattern recognition receptors and innate cellular responses, cytokines, lymphocytes, coagulation, and the complement system. A combination of factors causes increased susceptibility to infection and can contribute to a disturbed immune response during a septic event in patients with HIV. HIV-induced perturbations of the immune system depend on stage of infection and are only in part restored by combination antiretroviral therapy. Immunomodulatory treatments currently under development for sepsis might be particularly beneficial to patients with HIV co-infection because many pathogenic mechanisms in HIV and sepsis overlap.

Transcriptional profiling of Mycobacterium tuberculosis replicating ex vivo in blood from HIV- and HIV+ subjects

Hematogenous dissemination of Mycobacterium tuberculosis (M. tb) occurs during both primary and reactivated tuberculosis (TB). Although hematogenous dissemination occurs in non-HIV TB patients, in ∼80% of these patients, TB manifests exclusively as pulmonary disease. In contrast, extrapulmonary, disseminated, and/or miliary TB is seen in 60–70% of HIV-infected TB patients, suggesting that hematogenous dissemination is likely more common in HIV+ patients. To understand M. tb adaptation to the blood environment during bacteremia, we have studied the transcriptome of M. tb replicating in human whole blood. To investigate if M. tb discriminates between the hematogenous environments of immunocompetent and immunodeficient individuals, we compared the M. tb transcriptional profiles during replication in blood from HIV- and HIV+ donors. Our results demonstrate that M. tb survives and replicates in blood from both HIV- and HIV+ donors and enhances its virulence/pathogenic potential in the hematogenous environment. The M. tb blood-specific transcriptome reflects suppression of dormancy, induction of cell-wall remodeling, alteration in mode of iron acquisition, potential evasion of immune surveillance, and enhanced expression of important virulence factors that drive active M. tb infection and dissemination. These changes are accentuated during bacterial replication in blood from HIV+ patients. Furthermore, the expression of ESAT-6, which participates in dissemination of M. tb from the lungs, is upregulated in M. tb growing in blood, especially during growth in blood from HIV+ patients. Preliminary experiments also demonstrate that ESAT-6 promotes HIV replication in U1 cells. These studies provide evidence, for the first time, that during bacteremia, M. tb can adapt to the blood environment by modifying its transcriptome in a manner indicative of an enhanced-virulence phenotype that favors active infection. Additionally, transcriptional modifications in HIV+ blood may further accentuate M. tb virulence and drive both M. tb and HIV infection.

A reduction in adult blood stream infection and case fatality at a large African hospital following antiretroviral therapy roll-out

Introduction

Blood-stream infection (BSI) is one of the principle determinants of the morbidity and mortality associated with advanced HIV infection, especially in sub-Saharan Africa. Over the last 10 years, there has been rapid roll-out of anti-retroviral therapy (ART) and cotrimoxazole prophylactic therapy (CPT) in many high HIV prevalence African countries.

Methods

A prospective cohort of adults with suspected BSI presenting to Queen's Hospital, Malawi was recruited between 2009 and 2010 to describe causes of and outcomes from BSI. Comparison was made with a cohort pre-dating ART roll-out to investigate whether and how ART and CPT have affected BSI. Malawian census and Ministry of Health ART data were used to estimate minimum incidence of BSI in Blantyre district.

Results

2,007 patients were recruited, 90% were HIV infected. Since 1997/8, culture-confirmed BSI has fallen from 16% of suspected cases to 10% (p<0.001) and case fatality rate from confirmed BSI has fallen from 40% to 14% (p<0.001). Minimum incidence of BSI was estimated at 0.03/1000 years in HIV uninfected vs. 2.16/1000 years in HIV infected adults. Compared to HIV seronegative patients, the estimated incidence rate-ratio for BSI was 80 (95% CI:46–139) in HIV-infected/untreated adults, 568 (95% CI:302–1069) during the first 3 months of ART and 30 (95% CI:16–59) after 3 months of ART.

Conclusions

Following ART roll-out, the incidence of BSI has fallen and clinical outcomes have improved markedly. Nonetheless, BSI incidence remains high in the first 3 months of ART despite CPT. Further interventions to reduce BSI-associated mortality in the first 3 months of ART require urgent evaluation.

Bacteremia as a cause of fever in ambulatory, HIV-infected Mozambican adults: results and policy implications from a prospective observational study

Fever is typically treated empirically in rural Mozambique. We examined the distribution and antimicrobial susceptibility patterns of bacterial pathogens isolated from blood-culture specimens, and clinical characteristics of ambulatory HIV-infected febrile patients with and without bacteremia. This analysis was nested within a larger prospective observational study to evaluate the performance of new Mozambican guidelines for fever and anemia in HIV-infected adults (clinical trial registration NCT01681914, www.clinicaltrials.gov); the guidelines were designed to be used by non-physician clinicians who attended ambulatory HIV-infected patients in very resource-constrained peripheral health units. In 2012 (April-September), we recruited 258 HIV-infected adults with documented fever or history of recent fever in three sites within Zambézia Province, Mozambique. Although febrile patients were routinely tested for malaria, blood culture capacity was unavailable in Zambézia prior to study initiation. We confirmed bacteremia in 39 (15.1%) of 258 patients. The predominant organisms were non-typhoid Salmonella, nearly all resistant to multiple first-line antibiotics (ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole). Features most associated with bacteremia included higher temperature, lower CD4+ T-lymphocyte count, lower hemoglobin, and headache. Introduction of blood cultures allowed us to: 1) confirm bacteremia in a substantial proportion of patients; 2) tailor specific antimicrobial therapy for confirmed bacteremia based on known susceptibilities; 3) make informed choices of presumptive antibiotics for patients with suspected bacteremia; and 4) construct a preliminary clinical profile to help clinicians determine who would most likely benefit from presumptive bacteremia treatment. Our findings demonstrate that in resource-limited settings, there is urgent need to expand local microbiologic capacity to better identify and treat cases of bacteremia in HIV-infected and other patients, and to support surveillance. Data on the prevalence and susceptibility patterns of important pathogens can guide national formulary and prescribing practices.

Severity assessment of lower respiratory tract infection in Malawi: derivation of a novel index (SWAT-Bp) which outperforms CRB-65

Objective

To assess the validity of CRB-65 (Confusion, Respiratory rate >30 breaths/min, BP<90/60 mmHg, age >65 years) as a pneumonia severity index in a Malawian hospital population, and determine whether an alternative score has greater accuracy in this setting.

Design

Forty three variables were prospectively recorded during the first 48 hours of admission in all patients admitted to Queen Elizabeth Central Hospital, Malawi, for management of lower respiratory tract infection over a two month period (N = 240). Calculation of sensitivity and specificity for CRB-65 in predicting mortality was followed by multivariate modeling to create a score with superior performance in this population.

Results

Median age 37, HIV prevalence 79.9%, overall mortality 18.3%. CRB-65 predicted mortality poorly, indicated by the area under the ROC curve of 0.649. Independent predictors of death were: Male sex, “S” (AOR 2.6); Wasting, “W” (AOR 6.6); non-ambulatory, “A” (AOR 2.5); Temp >38°C or <35°C, “T” (AOR 3.2); BP<100/60, “Bp” (AOR 3.7). Combining these factors to form a severity index (SWAT-Bp) predicted mortality with high sensitivity and specificity (AUC: 0.867). Mortality for scores 0–5 was 0%, 3.3%, 7.4%, 29.2%, 61.5% and 87.5% respectively. A score ≥3 was 84% sensitive and 77% specific for mortality prediction, with a negative predictive value of 95.8%.

Conclusion

CRB-65 performs poorly in this population. The SWAT-Bp score can accurately stratify patients; ≤2 indicates non-severe infection (mortality 4.4%) and ≥3 severe illness (mortality 45%).

Prevalence of clinically captured and confirmed malaria among HIV seropositve clinic attendants in five hospitals in Ghana

Background

Malaria is associated with an increase in HIV viral load and a fall in CD4-cell count. Conversely, HIV infection disrupts the acquired immune responses to malaria and the efficacy of antimalarial drugs. This study was carried out in five Ghanaian hospitals to estimate the prevalence of clinically confirmed malaria among HIV patients by evaluating their hospital records.

Methods

This retrospective descriptive cross sectional study reviewed and collected data on malaria, using Case Record Forms from HIV patients’ folders in five hospitals in Ghana.

Results

There were 933 patients records made up of 272 (29.2%) males and 661 (70.8%) females. Majority of the patients were aged between 21–40 (63.6%) years and the rest were between the ages 1–20 (2.8%) years, 41–60 (31.6%) years and 61–80 (2.1%) years of age.

A total of 38.1% (355/933) of the patients were clinically suspected of having clinical malaria. Of these 339 (95.5%) were referred to the laboratory for confirmation of the diagnosis of malaria. Only 4.4% (15/339) of patients tested were confirmed as cases of malaria among the patients that were clinically suspected of having malaria and subsequently confirmed. Fever, was not significantly associated with a confirmed diagnosis of malaria [OR = 3.11, 95% CI: (0.63, 15.37), P = 0.142].

Conclusions

There was a 4.4% prevalence of confirmed malaria and 38.1% of presumptively diagnosed malaria from the case records of HIV patients from the selected hospitals in Ghana.

Community-acquired bacterial bloodstream infections in HIV-infected patients: a systematic review

Information on community-acquired bacterial bloodstream infections (BSIs) in individuals infected with human immunodeficiency virus (HIV) is limited. We conducted a systematic literature review. The case fraction of community-acquired bacterial BSIs in hospitalized patients is 20% and 30% in adults and children, respectively, compared to 9% in HIV-negative adults and children. Worldwide, the main pathogens of community-acquired BSI are nontyphoid salmonellae (NTS), Streptococcus pneumoniae, Escherichia coli, and Staphylococcus aureus, but regional differences are apparent, especially for S. pneumoniae. Compared to HIV-negative populations, HIV patients are particularly at risk to develop NTS bacteremia. Bacteremia incidence is related to immunosuppression, and antiretroviral therapy reduces the incidence of BSI in HIV patients (rate ratios, 0.63-0.02). Mortality rates varied between 7% and 46%. These results suggest that bacterial BSI is more likely to be found in HIV-positive than in HIV-negative patients upon hospitalization, and that causative pathogens vary by region.

Preventing intensive care admissions for sepsis in tropical Africa (PICASTA): an extension of the international pediatric global sepsis initiative: an African perspective

BACKGROUND

The Global Sepsis Initiative recommends prevention of sepsis through immunizations, vitamins, breast feeding, and other important interventions. In our study, we consider a second set of proposals for preventing intensive care admissions for sepsis in tropical Africa, which have been specifically designed to further prevent ICU admissions for sepsis in the group A nation hospital setting.

OBJECTIVES

To reduce admissions with severe sepsis in an ICU of a group A nation through the identification of challenges leading to preventable, foreseeable, or nosocomial sepsis specific to our setting.

METHODS

Malawi is one of the poorest countries in the world. Lacking the ability to comply with standard sepsis treatment, we conducted over 4 years several studies, audits, and surveys to identify challenges leading to preventable pediatric sepsis in our setting. We developed a method to identify malnourished children through a "gatekeeper" in the theaters without any equipment, tried to implement the World Health Organization's Safe Surgery Campaign checklist, evaluated our educational courses for the districts to improve the quality of referrals, looked into the extreme fasting times discovered in our hospital, trained different cadres in the districts to deal with peripartal and posttraumatic sepsis, and identified the needs in human resources to deal with pediatric sepsis in our setting.

RESULTS

Six foci were identified as promising to work on in future. Focus 1: Preventing elective operations and procedures in malnourished children in the hospital and in the district: 134 of 145 nurses (92.4%) and even 25 of 31 African laymen (80.6%) were able to identify malnourished children with their own fingers. Focus 2: Preventing sepsis-related problems in emergencies through the implementation of the Safe Surgery Campaign checklist: only 100 of 689 forms (14.5%) were filled in due to challenges in ownership, communication responsibility, and time constraints. Focus 3: Preventing sepsis through the reduction of unwise referrals: our courses toward this topic reached 82-100% satisfaction of the 391 participants for relevance, presentation applicability, content, and teaching technique. Focus 4: Preventing sepsis-related problems through reduction of excessive fasting times in our hospital: necessity for action was documented by a mean fasting time of 10.2 hours (SD, 4.4 hr). Focus 5: Concentration on two extremely sepsis-relevant health challenges for children in Malawian districts, trauma and peripartal complications: numbers after our courses in the trained two districts showed a reduction in the maternal mortality rate (from 150.3 to 55 and 234.2 to 75.2), an inconclusive result for posttraumatic deaths and the identification of 44 future instructors. Focus 6: Implementation of a Master in Medicine (anesthesia and intensive care) and improvement of training in anesthesia for all cadres resulted in the first five anesthetic registrars in training and enhanced numbers in all other cadres in anesthesia dealing in own responsibility with pediatric sepsis.

CONCLUSIONS

Every hospital can try to improve sepsis prevention on a local level by the Preventing Intensive Care Admissions for Sepsis in Tropical Africa approach. This will help support the promotion of the regionally adjusted Global Sepsis Initiative guidelines and the future global implementation of feasible bundles as a gold standard for resource-poor countries.

Chest radiography for predicting the cause of febrile illness among inpatients in Moshi, Tanzania

AIM

To describe chest radiographic abnormalities and assess their usefulness for predicting causes of fever in a resource-limited setting.

MATERIALS AND METHODS

Febrile patients were enrolled in Moshi, Tanzania, and chest radiographs were evaluated by radiologists in Tanzania and the United States. Radiologists were blinded to the results of extensive laboratory evaluations to determine the cause of fever.

RESULTS

Of 870 febrile patients, 515 (59.2%) had a chest radiograph available; including 268 (66.5%) of the adolescents and adults, the remainder were infants and children. One hundred and nineteen (44.4%) adults and 51 (20.6%) children were human immunodeficiency virus (HIV)-infected. Among adults, radiographic abnormalities were present in 139 (51.9%), including 77 (28.7%) with homogeneous and heterogeneous lung opacities, 26 (9.7%) with lung nodules, 25 (9.3%) with pleural effusion, 23 (8.6%) with cardiomegaly, and 13 (4.9%) with lymphadenopathy. Among children, radiographic abnormalities were present in 87 (35.2%), including 76 (30.8%) with homogeneous and heterogeneous lung opacities and six (2.4%) with lymphadenopathy. Among adolescents and adults, the presence of opacities was predictive of Streptococcus pneumoniae and Coxiella burnetii, whereas the presence of pulmonary nodules was predictive of Histoplasma capsulatum and Cryptococcus neoformans.

CONCLUSIONS

Chest radiograph abnormalities among febrile inpatients are common in northern Tanzania. Chest radiography is a useful adjunct for establishing an aetiologic diagnosis of febrile illness and may provide useful information for patient management, in particular for pneumococcal disease, Q fever, and fungal infections.

[Sepsis - Knowledge of non-physician personnel in Africa. A cross-sectional study in Malawian district hospitals]

BACKGROUND

Malawi has one of the worst human resource situations in the world and each clinically working doctor has to serve around 50,000 patients. There are almost no Malawian specialists physicians so that in the district hospitals it is usually non-medical staff (e.g. anesthesia clinical officer) who have the responsibility for severely sick patients with sepsis. At the Queen Elizabeth Central Hospital we have organized different courses over the years to support these colleagues.

METHODS

Anonymous questionnaires with 10 multiple choice and 4 feedback-related questions were distributed to 115 participants in order to achieve an overview of the basic knowledge related to sepsis in the Malawian setting.

RESULTS

In total 64.2 % of the questions were answered correctly with only minor differences between the 4 groups of participants from different professional backgrounds. Despite a relatively good knowledge in practical therapy the question concerning the therapeutic strategies of the Surviving Sepsis Campaign obtained the worst score with 6 %. After the course there was a 17 % increase in correctly answered questions. Besides an overview over the diagnostic and therapeutic situation for sepsis in the districts we received suggestions and critical comments for a better adjustment of our courses towards the reality of rural district hospitals.

CONCLUSIONS

Healthcare workers in Malawi are not aware of key recommendations of the Surviving Sepsis Campaign. Guidelines have to be adapted to the specific healthcare structures in underdeveloped countries. We realized the wish and the desire of the participants for more training and more courses in Malawi. In order to be able to support these needs we would like to invite cooperation from interested institutions and colleagues for a special sepsis course on the occasion of the annual World Sepsis Days.

Six-month mortality among HIV-infected adults presenting for antiretroviral therapy with unexplained weight loss, chronic fever or chronic diarrhea in Malawi

Background

In sub-Saharan Africa, early mortality is high following initiation of antiretroviral therapy (ART). We investigated 6-month outcomes and factors associated with mortality in HIV-infected adults being assessed for ART initiation and presenting with weight loss, chronic fever or diarrhea, and with negative TB sputum microscopy.

Methods

A prospective cohort study was conducted in Malawi, investigating mortality in relation to ART uptake, microbiological findings and treatment of opportunistic infection (OIs), 6 months after meeting ART eligibility criteria.

Results

Of 469 consecutive adults eligible for ART, 74(16%) died within 6 months of enrolment, at a median of 41 days (IQR 20–81). 370(79%) started ART at a median time of 18 days (IQR 7–40) after enrolment. Six-month case-fatality rates were higher in patients with OIs; 25/121(21%) in confirmed/clinical TB and 10/50(20%) with blood stream infection (BSI) compared to 41/308(13%) in patients with no infection identified. Median TB treatment start was 27 days (IQR 17–65) after enrolment and mortality [8 deaths (44%)] was significantly higher among 18 culture-positive patients with delayed TB diagnosis compared to patients diagnosed clinically and treated promptly with subsequent culture confirmation [6/34 (18%);p = 0.04]. Adjusted multivariable analysis, excluding deaths in the first 21 days, showed weight loss >10%, low CD4 count, severe anemia, laboratory-only TB diagnosis, and not initiating ART to be independently associated with increased risk of death.

Conclusions

Mortality remains high among chronically ill patients eligible for ART. Prompt initiation of ART is vital: more than half of deaths were among patients who never started ART. Diagnostic and treatment delay for TB was strongly associated with risk of death. More than half of deaths occurred without identification of a specific infection. ART programmes need access to rapid point-of-care-diagnostic tools for OIs. The role of early empiric OI treatment in this population requires further evaluation in clinical trials.

High prevalence of Non-typhoid salmonella bacteraemia among febrile HIV adult patients admitted at a tertiary Hospital, North-Western Tanzania

Background

Bacterial blood stream infections constitute a significant public-health problem and it is an important cause of morbidity and mortality in HIV infected patients. Little is known in developing countries regarding salmonella bacteraemia among HIV patients. The purpose of this study was to determine the bacterial pathogens causing blood stream infection among febrile adults attending in a tertiary hospital North-Western, Tanzania.

Methods

A prospective cross-sectional study involving 346 consecutive, febrile adult patients admitted at Bugando Medical Centre was conducted. Demographic and other data were collected using standardized questionnaires. Blood culture was done followed by susceptibility testing using disc diffusion method. HIV testing was also performed as per Tanzania national algorithm and total white blood cell counts and CD4+ counts determined.

Results

Of 346 febrile adult patients 33 (9.5%) had blood stream infections. The common isolates were Salmonella spp 13(39.4%), Escherichia coli 8 (24.2%), Streptococcus pneumonia 5(15.2%), Staphylococcus aureus 4(12.1%), Citrobacter spp 1(3%), Streptococcus pyogenes 1(3%) and Klebsiella pneumonia 1(3%). A total of 156 (45.1%) patients were HIV infected; of whom 12/156 (7.6%) were infected by non-typhoid Salmonella spp compared to 1/190 (0.5%) of non-HIV infected patients (RRR 11.2, p=0.029) infected with Salmonella typhi. HIV infected patients with bacteraemia had significantly lower CD4+ count than those without bacteraemia (median 28 vs. 88 cells/ml, p=0.01). Patients with salmonella bacteraemia had significantly lower median of WBC than those with non-salmonella as well as those without bacteraemia (median, 3.6 vs. 17.5 vs. 9.8x10⁹, p=0.0001). All Salmonella spp were sensitive to ceftriaxone and imipenem, while being 84%, 69.2%, 38% and 8% resistant to chloramphenicol, ampicillin, sulphamethaxazole/trimethoprim and ciprofloxacin respectively. Predictors of mortality were HIV infection (OR 2.3, p=0.006), Glasgow coma score of less than 15 (OR 3.4, p=0.0001) and night sweats (OR 2.4, p=0.014).

Conclusion

Non-typhoid Salmonella spp that are highly resistant to common antibiotics are predominant cause of bacterial blood stream infection among HIV patients attending Bugando Medical Centre. Continuous surveillance and intervention strategies should be put in place to monitor and manage cases of bloodstream infections in HIV-positive patients in Mwanza, Tanzania.

Severe febrile illness in adult hospital admissions in Tanzania: a prospective study in an area of high malaria transmission

Severe febrile illness is a major cause of adult hospital admission in Africa. Studies of non-malarial fever come largely from children or from high HIV prevalence settings. This prospective study of adult admissions with severe febrile illness in a malaria-endemic area with moderate/low HIV prevalence investigated admission diagnosis as well as final diagnosis based on results of investigations. Severe malaria was the admission diagnosis in 148/198 (74.7%) cases. Plasmodium falciparum was identified in 38/188 (20.2%) admissions and 26/198 (13.1%) were bacteraemic, with 13/25 (52%) prescribed empirical antibiotics. HIV was equally common among those with (16/37; 43.2%) and without P. falciparum (50/138; 36.2%) (p=0.44). In 6/22 (27.3%) deaths, blood cultures were positive for a pathogen, with Streptococcus pneumoniae, Escherichia coli and non-Typhi Salmonella predominating. Chest radiography was suspicious for bacterial/mycobacterial disease in 5/22 additional deaths. Systemic inflammatory response syndrome criteria were more sensitive but less specific than WHO severe malaria criteria for predicting mortality. Malaria is overdiagnosed in adults with severe febrile illness and was not associated with mortality in the absence of co-infection in this high-incidence setting. Adults with severe febrile illness should be tested for malaria and HIV using rapid, sensitive tests. Early antibiotic use should be promoted. Improved diagnostics for invasive bacterial disease are needed.

Live attenuated S. Typhimurium vaccine with improved safety in immuno-compromised mice

Live attenuated vaccines are of great value for preventing infectious diseases. They represent a delicate compromise between sufficient colonization-mediated adaptive immunity and minimizing the risk for infection by the vaccine strain itself. Immune defects can predispose to vaccine strain infections. It has remained unclear whether vaccine safety could be improved via mutations attenuating a vaccine in immune-deficient individuals without compromising the vaccine's performance in the normal host. We have addressed this hypothesis using a mouse model for Salmonella diarrhea and a live attenuated Salmonella Typhimurium strain (ssaV). Vaccination with this strain elicited protective immunity in wild type mice, but a fatal systemic infection in immune-deficient cybb^−/−nos2^−/− animals lacking NADPH oxidase and inducible NO synthase. In cybb^−/−nos2^−/− mice, we analyzed the attenuation of 35 ssaV strains carrying one additional mutation each. One strain, Z234 (ssaV SL1344_3093), was >1000-fold attenuated in cybb^−/−nos2^−/− mice and ≈100 fold attenuated in tnfr1^−/− animals. However, in wt mice, Z234 was as efficient as ssaV with respect to host colonization and the elicitation of a protective, O-antigen specific mucosal secretory IgA (sIgA) response. These data suggest that it is possible to engineer live attenuated vaccines which are specifically attenuated in immuno-compromised hosts. This might help to improve vaccine safety.

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.

Rapid discrimination of Salmonella enterica serovar Typhi from other serovars by MALDI-TOF mass spectrometry

Systemic infections caused by Salmonella enterica are an ongoing public health problem especially in Sub-Saharan Africa. Essentially typhoid fever is associated with high mortality particularly because of the increasing prevalence of multidrug-resistant strains. Thus, a rapid blood-culture based bacterial species diagnosis including an immediate sub-differentiation of the various serovars is mandatory. At present, MALDI-TOF based intact cell mass spectrometry (ICMS) advances to a widely used routine identification tool for bacteria and fungi. In this study, we investigated the appropriateness of ICMS to identify pathogenic bacteria derived from Sub-Saharan Africa and tested the potential of this technology to discriminate S. enterica subsp. enterica serovar Typhi (S. Typhi) from other serovars. Among blood culture isolates obtained from a study population suffering from febrile illness in Ghana, no major misidentifications were observed for the species identification process, but serovars of Salmonella enterica could not be distinguished using the commercially available Biotyper database. However, a detailed analysis of the mass spectra revealed several serovar-specific biomarker ions, allowing the discrimination of S. Typhi from others. In conclusion, ICMS is able to identify isolates from a sub-Saharan context and may facilitate the rapid discrimination of the clinically and epidemiologically important serovar S. Typhi and other non-S. Typhi serovars in future implementations.

High prevalence of tuberculosis and serious bloodstream infections in ambulatory individuals presenting for antiretroviral therapy in Malawi

Background

Tuberculosis (TB) and serious bloodstream infections (BSI) may contribute to the high early mortality observed among patients qualifying for antiretroviral therapy (ART) with unexplained weight loss, chronic fever or chronic diarrhea.

Methods and Findings

A prospective cohort study determined the prevalence of undiagnosed TB or BSI among ambulatory HIV-infected adults with unexplained weight loss and/or chronic fever, or diarrhea in two routine program settings in Malawi. Subjects with positive expectorated sputum smears for AFB were excluded. Investigations Bacterial and mycobacterial blood cultures, cryptococcal antigen test (CrAg), induced sputum (IS) for TB microscopy and solid culture, full blood count and CD4 lymphocyte count. Among 469 subjects, 52 (11%) had microbiological evidence of TB; 50 (11%) had a positive (non-TB) blood culture and/or positive CrAg. Sixty-five additional TB cases were diagnosed on clinical and radiological grounds. Nontyphoidal Salmonellae (NTS) were the most common blood culture pathogens (29 cases; 6% of participants and 52% of bloodstream isolates). Multivariate analysis of baseline clinical and hematological characteristics found significant independent associations between oral candidiasis or lymphadenopathy and TB, marked CD4 lymphopenia and NTS infection, and severe anemia and either infection, but low positive likelihood ratios (<2 for all combinations).

Conclusions

We observed a high prevalence of TB and serious BSI, particularly NTS, in a program cohort of chronically ill HIV-infected outpatients. Baseline clinical and hematological characteristics were inadequate predictors of infection. HIV clinics need better rapid screening tools for TB and BSI. Clinical trials to evaluate empiric TB or NTS treatment are required in similar populations.

Identification of a common immune signature in murine and human systemic Salmonellosis

Despite the importance of Salmonella infections in human and animal health, the target antigens of Salmonella-specific immunity remain poorly defined. We have previously shown evidence for antibody-mediating protection against invasive Salmonellosis in mice and African children. To generate an overview of antibody targeting in systemic Salmonellosis, a Salmonella proteomic array containing over 2,700 proteins was constructed and probed with immune sera from Salmonella-infected mice and humans. Analysis of multiple inbred mouse strains identified 117 antigens recognized by systemic antibody responses in murine Salmonellosis. Importantly, many of these antigens were independently identified as target antigens using sera from Malawian children with Salmonella bacteremia, validating the study of the murine model. Furthermore, vaccination with SseB, the most prominent antigenic target in Malawian children, provided mice with significant protection against Salmonella infection. Together, these data uncover an overlapping immune signature of disseminated Salmonellosis in mice and humans and provide a foundation for the generation of a protective subunit vaccine.

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.

Development of protective immunity to Salmonella, a mucosal pathogen with a systemic agenda

Salmonella infections can cause a range of intestinal and systemic diseases in human and animal hosts. Although some Salmonella serovars initiate a localized intestinal inflammatory response, others use the intestine as a portal of entry to initiate a systemic infection. Considerable progress has been made in understanding bacterial invasion and dissemination strategies, as well as the nature of the Salmonella-specific immune response to oral infection. Innate and adaptive immunity are rapidly initiated after oral infection, but these effector responses can also be hindered by bacterial evasion strategies. Furthermore, although Salmonella resides within intramacrophage phagosomes, recent studies have highlighted a surprising collaboration of CD4 Th1, Th17, and B-cell responses in mediating resistance to Salmonella infection.