Community-acquired bacteremia in human immunodeficiency virus-infected children in Harare, Zimbabwe

Risk of community- and hospital-acquired bacteremia and profile of antibiotic resistance in children hospitalized with severe acute malnutrition in Niger

OBJECTIVE

To estimate the prevalence and antibiotic resistance profile of community- and hospital-acquired bacteremia among hospitalized children with severe acute malnutrition in Niger.

METHODS

A descriptive, longitudinal study was conducted in an intensive nutritional rehabilitation center in Madarounfa, Niger. Children aged 6 to 59 months admitted for inpatient treatment of complicated severe acute malnutrition (n=2187) had blood specimens drawn at admission to assess prevalence of community-acquired bacteremia. Subsequent specimens were drawn per physician discretion to assess incidence of hospital-acquired bacteremia. Antibiotic susceptibility testing was performed on positive blood cultures.

RESULTS

The prevalence of community-acquired bacteremia at admission was at least 9.1% (95% confidence interval [CI]: 8.1, 10.4%), with non-typhoid Salmonella identified in over half (57.8%) of cases. The cumulative incidence of hospital-acquired bacteremia was estimated at 1.2% (95% CI: 0.8, 1.7%), among which the most common organisms were Klebsiella pneumoniae (19.4%), Acinetobacter baumannii (16.1%), Enterococcus faecalis (12.9%), and Escherichia coli (12.9%). In community-acquired bacteremia, 58% cases were resistant to amoxicillin-clavulanate; 100% of hospital-acquired bacteremia cases were resistant to amoxicillin and amoxicillin-clavulanate. Mortality risk was elevated among children with hospital-acquired bacteremia (risk ratio [RR] = 9.32) and community-acquired bacteremia (RR = 2.67).

CONCLUSION

Bacteremia was a significant contributor to mortality. Antibiotic resistance poses a challenge to effective clinical management of severe acute malnutrition.

Bacterial pathogens and resistance causing community acquired paediatric bloodstream infections in low- and middle-income countries: a systematic review and meta-analysis

Background

Despite a high mortality rate in childhood, there is limited evidence on the causes and outcomes of paediatric bloodstream infections from low- and middle-income countries (LMICs). We conducted a systematic review and meta-analysis to characterize the bacterial causes of paediatric bloodstream infections in LMICs and their resistance profile.

Methods

We searched Pubmed and Embase databases between January 1st 1990 and October 30th 2019, combining MeSH and free-text terms for “sepsis” and “low-middle-income countries” in children. Two reviewers screened articles and performed data extraction to identify studies investigating children (1 month-18 years), with at least one blood culture. The main outcomes of interests were the rate of positive blood cultures, the distribution of bacterial pathogens, the resistance patterns and the case-fatality rate. The proportions obtained from each study were pooled using the Freeman-Tukey double arcsine transformation, and a random-effect meta-analysis model was used.

Results

We identified 2403 eligible studies, 17 were included in the final review including 52,915 children (11 in Africa and 6 in Asia). The overall percentage of positive blood culture was 19.1% [95% CI: 12.0–27.5%]; 15.5% [8.4–24.4%] in Africa and 28.0% [13.2–45.8%] in Asia. A total of 4836 bacterial isolates were included in the studies; 2974 were Gram-negative (63.9% [52.2–74.9]) and 1858 were Gram-positive (35.8% [24.9–47.5]). In Asia, Salmonella typhi (26.2%) was the most commonly isolated pathogen, followed by Staphylococcus aureus (7.7%) whereas in Africa, S. aureus (17.8%) and Streptococcus pneumoniae (16.8%) were predominant followed by Escherichia coli (10.7%). S. aureus was more likely resistant to methicillin in Africa (29.5% vs. 7.9%), whereas E. coli was more frequently resistant to third-generation cephalosporins (31.2% vs. 21.2%), amikacin (29.6% vs. 0%) and ciprofloxacin (36.7% vs. 0%) in Asia. The overall estimate for case-fatality rate among 8 studies was 12.7% [6.6–20.2%]. Underlying conditions, such as malnutrition or HIV infection were assessed as a factor associated with bacteraemia in 4 studies each.

Conclusions

We observed a marked variation in pathogen distribution and their resistance profiles between Asia and Africa. Very limited data is available on underlying risk factors for bacteraemia, patterns of treatment of multidrug-resistant infections and predictors of adverse outcomes.

The burden of vaccine-preventable diseases among HIV-infected and HIV-exposed children in sub-Saharan Africa: a systematic review and meta-analysis

There are knowledge gaps regarding evidence-based research on the burden of vaccine-preventable diseases among human immunodeficiency virus (HIV)-infected and HIV-exposed children aged <18 years in sub-Saharan Africa. It is therefore essential to determine the trend and burden of vaccine-preventable diseases. We completed a systematic review and meta-analysis to identify the incidence, prevalence and case-fatality rates (CFR) attributed to various vaccine-preventable diseases among HIV-infected and HIV-exposed children in sub-Saharan Africa. The trends in the prevalence of vaccine-preventable diseases among HIV-infected and HIV-exposed children were also determined. Nine studies on tuberculosis (TB) were pooled to give an overall incidence rate estimate of 60 (95% confidence interval [CI] 30-70) per 1,000 child-years. The incidence of pneumococcal infections varied between 109-1509 per 100,000 while pertussis was between 2.9 and 3.7 per 1000 child-year. Twenty-two TB prevalence studies reported an estimated prevalence of 16%. Fifteen prevalence studies on hepatitis B infection were pooled together with an estimated prevalence of 5%. The pooled prevalence for pneumococcal infections was 2% while rotavirus diarrhoea reported a prevalence of 13%. Twenty-nine studies on TB were pooled to give an overall CFR estimate of 17% while pneumococcal infections in HIV-infected and exposed children were pooled together with a resultant rate of 15%. Some of the vaccine-preventable diseases still have high incidences, prevalence and CFR among HIV-infected and HIV-exposed children. There is also a dearth of research data on the burden of several vaccine-preventable diseases among HIV-infected and exposed children and a need for more studies in this area.

Should first-line empiric treatment strategies cover coagulase-negative staphylococcal infections in severely malnourished or HIV-infected children in Kenya?

Background

Bloodstream infection is a common cause of morbidity in children aged <5 years in developing countries. In studies reporting bacteremia in Africa, coagulase-negative Staphylococci (CoNS) are commonly isolated. However, it is currently unclear whether children who are highly susceptible to infection because of severe acute malnutrition (SAM) or HIV should be treated with antimicrobials specifically to cover CoNS. We aimed to determine the clinical significance of CoNS amongst children admitted to a rural hospital in Kenya in relation to nutritional and HIV status.

Methods

Systematically collected clinical and microbiological surveillance data from children aged 6–59 months admitted to Kilifi County Hospital (2007–2013) were analysed. Multivariable regression was used to test associations between CoNS isolation from blood cultures and SAM (MUAC <11.5cm or nutritional oedema (kwashiorkor)), and HIV serostatus; and among children with SAM or HIV, associations between CoNS isolation and mortality, duration of hospitalization and clinical features.

Results

CoNS were isolated from blood culture in 906/13,315 (6.8%) children, of whom 135/906 (14.9%) had SAM and 54/906 (6.0%) were HIV antibody positive. CoNS isolation was not associated with SAM (MUAC<11.5cm (aOR 1.11, 95% CI 0.88–1.40) or kwashiorkor (aOR 0.84, 95% CI 0.48–1.49)), or a positive HIV antibody test (aOR 1.25, 95% CI 0.92–1.71). Among children with SAM or a positive HIV antibody test, CoNS isolation was not associated with mortality or prolonged hospitalization.

Conclusion

In a large, systematic study, there was no evidence that antimicrobial therapy should specifically target CoNS amongst children with SAM or HIV-infection or exposure.

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.

Challenges in the Etiology and Diagnosis of Acute Febrile Illness in Children in Low- and Middle-Income Countries

Acute febrile illness is a common cause of hospital admission, and its associated infectious causes contribute to substantial morbidity and death among children worldwide, especially in low- and middle-income countries. Declining transmission of malaria in many regions, combined with the increasing use of rapid diagnostic tests for malaria, has led to the increasing recognition of leptospirosis, rickettsioses, respiratory viruses, and arboviruses as etiologic agents of fevers. However, clinical discrimination between these etiologies can be difficult. Overtreatment with antimalarial drugs is common, even in the setting of a negative test result, as is overtreatment with empiric antibacterial drugs. Viral etiologies remain underrecognized and poorly investigated. More-sensitive diagnostics have led to additional dilemmas in discriminating whether a positive test result reflects a causative pathogen. Here, we review and summarize the current epidemiology and focus particularly on children and the challenges for future research.

Trends in paediatric bloodstream infections at a South African referral hospital

BACKGROUND

The epidemiology of paediatric bloodstream infection (BSI) in Sub-Saharan Africa is poorly documented with limited data on hospital-acquired sepsis, impact of HIV infection, BSI trends and antimicrobial resistance.

METHODS

We retrospectively reviewed paediatric BSI (0-14 years) at Tygerberg Children's Hospital between 1 January 2008 and 31 December 2013 (excluding neonatal wards). Laboratory and hospital data were used to determine BSI rates, blood culture contamination, pathogen profile, patient demographics, antimicrobial resistance and factors associated with mortality. Fluconazole resistant Candida species, methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant Acinetobacter baumannii and extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae were classified as antimicrobial resistant pathogens.

RESULTS

Of 17001 blood cultures over 6 years, 935 cultures isolated 979 pathogens (5.5% yield; 95% CI 5.3-5.7%). Contamination rates were high (6.6%, 95% CI 6.4-6.8%), increasing over time (p = 0.003). Discrete BSI episodes were identified (n = 864) with median patient age of 7.5 months, male predominance (57%) and 13% HIV prevalence. BSI rates declined significantly over time (4.6-3.1, overall rate 3.5 per 1000 patient days; 95% CI 3.3-3.7; Chi square for trend p = 0.02). Gram negative pathogens predominated (60% vs 33% Gram positives and 7% fungal); Klebsiella pneumoniae (154; 17%), Staphylococcus aureus (131; 14%) and Escherichia coli (97; 11%) were most prevalent. Crude BSI mortality was 20% (176/864); HIV infection, fungal, Gram negative and hospital-acquired sepsis were significantly associated with mortality on multivariate analysis. Hospital-acquired BSI was common (404/864; 47%). Overall antimicrobial resistance rates were high (70% in hospital vs 25% in community-acquired infections; p < 0.0001); hospital-acquired infection, infancy, HIV-infection and Gram negative sepsis were associated with resistance. S. pneumoniae BSI declined significantly over time (58/465 [12.5%] to 33/399 [8.3%]; p =0.04).

CONCLUSION

Although BSI rates declined over time, children with BSI had high mortality and pathogens exhibited substantial antimicrobial resistance in both community and hospital-acquired infections. Blood culture sampling technique and local options for empiric antimicrobial therapy require re-evaluation.

Antimicrobial drug resistance among clinically relevant bacterial isolates in sub-Saharan Africa: a systematic review

BACKGROUND

Little is known about the prevalence of antimicrobial resistance (AMR) amongst bacterial pathogens in sub-Saharan Africa (sSA), despite calls for continent-wide surveillance to inform empirical treatment guidelines.

METHODS

We searched PubMed and additional databases for susceptibility data of key pathogens for surveillance, published between 1990 and 2013. Extracted data were standardized to a prevalence of resistance in populations of isolates and reported by clinical syndrome, microorganism, relevant antimicrobial drugs and region.

RESULTS

We identified 2005 publications, of which 190 were analysed. Studies predominantly originated from east sSA (61%), were hospital based (60%), were from an urban setting (73%) and reported on isolates from patients with a febrile illness (42%). Quality procedures for susceptibility testing were described in <50% of studies. Median prevalence (MP) of resistance to chloramphenicol in Enterobacteriaceae, isolated from patients with a febrile illness, ranged between 31.0% and 94.2%, whilst MP of resistance to third-generation cephalosporins ranged between 0.0% and 46.5%. MP of resistance to nalidixic acid in Salmonella enterica Typhi ranged between 15.4% and 43.2%. The limited number of studies providing prevalence data on AMR in Gram-positive pathogens or in pathogens isolated from patients with a respiratory tract infection, meningitis, urinary tract infection or hospital-acquired infection suggested high prevalence of resistance to chloramphenicol, trimethoprim/sulfamethoxazole and tetracycline and low prevalence to third-generation cephalosporins and fluoroquinolones.

CONCLUSIONS

Our results indicate high prevalence of AMR in clinical bacterial isolates to antimicrobial drugs commonly used in sSA. Enhanced approaches for AMR surveillance are needed to support empirical therapy in sSA.

Epidemiology of Staphylococcus aureus bacteraemia at a tertiary children's hospital in Cape Town, South Africa

Background

Staphylococcus aureus is an important pathogen in paediatric patients with bloodstream infections. The epidemiology of S. aureus bacteraemia, however, has not been well documented in children in South Africa.

Methods

A retrospective study was conducted at a children’s hospital in Cape Town, South Africa, to investigate the epidemiology of S. aureus bacteraemia from 2007-2011. The incidence, clinical presentation, risk factors, management and outcomes of methicillin sensitive S. aureus (MSSA) and methicillin resistant S. aureus (MRSA) bacteraemia were compared.

Results

Over the five year study period, 365 episodes of S. aureus bacteraemia were identified. The annual incidence was 3.28 cases per 1000 hospital admissions. MRSA was responsible for 26% of S. aureus bacteraemia and 72% of nosocomial infections. Only six possible cases of community-acquired MRSA infections were described. MSSA bacteraemia was more likely to present as pulmonary and bone or joint infections, while bacteraemia without a source was the most common presentation with MRSA.  Infants, children with malnutrition, and residents of long-term care facilities were at highest risk for MRSA bacteraemia. The overall case fatality rate for S. aureus bacteraemia was 8.8% over five years, with MRSA being the only significant risk factor for mortality.

Conclusion

The incidence of S. aureus bacteraemia and MRSA bacteraemia in children has remained stable over the past five years. MRSA is a predominantly nosocomial pathogen in children with S. aureus bacteraemia in Cape Town, South Africa.

Coagulase-negative staphylococci in an HIV-infected child causing pancytopaenia

Although coagulase-negative staphylococci (CONS) constitute normal flora of the human body, some species can produce human infections, particularly when the host defense is breached. There is little evidence of the pathogenicity of CONS in HIV-infected individuals. We present the case of a 14-year-old HIV-infected boy who presented with a right lower zone pneumonia and a cutaneous abscess, following which he developed pancytopaenia due to underlying CONS infection that responded to antibiotic treatment.

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.

Bacteremia, causative agents and antimicrobial susceptibility among HIV-1-infected children on antiretroviral therapy in Uganda and Zimbabwe

BACKGROUND

Bacteremia is common in HIV-infected children in Africa, including after start of antiretroviral therapy (ART), but there are limited data on causative pathogens and their antimicrobial sensitivity patterns in this population.

METHODS

We analyzed data on blood cultures taken from HIV-infected children developing acute febrile illness after enrollment to the Antiretroviral Research for Watoto (ARROW) clinical trial in Uganda and Zimbabwe. Patterns of bacterial pathogens and their antimicrobial susceptibilities were determined and bacteremia rates calculated over time from ART initiation.

RESULTS

A total of 848 blood cultures were obtained from 461 children, of which 123 (14.5%) from 105 children (median age 3.5 years, 51% girls) were culture positive, including 75 (8.8%) with clearly pathogenic organisms. The event rates for positive cultures with clearly pathogenic organisms after 0-1, 2-3, 4-11 and ≥12 months on ART were 13.3, 11.4, 2.1 and 0.3 per 1000 person-months of follow-up, respectively. The pathogens isolated (n; %) were Streptococcus pneumoniae (36; 28.3%), Staphylococcus aureus (11; 8.7%), Klebsiella pneumoniae (6; 4.7%), Pseudomonas aeruginosa (6; 4.7%), Salmonella spp (6; 4.7%), Escherichia coli (5; 3.9%), Haemophilus influenzae (1; 0.8%) and fungal spp (4; 3.1%). Other bacteria of doubtful pathogenicity (n = 52; 42%) were also isolated. Most isolates tested were highly (80-100%) susceptible to ceftriaxone, cefotaxime and ciprofloxacin; very few (~5%) were susceptible to cotrimoxazole; S. pneumoniae had high susceptibility to amoxicillin/ampicillin (80%).

CONCLUSIONS

Rates of proven bacteremia were >20-fold higher immediately after starting ART compared with 12 months later in African HIV-infected children. S. pneumoniae was most commonly isolated, suggesting need for pneumococcal vaccination and effective prophylactic antibiotics.

Antibiotics as part of the management of severe acute malnutrition

BACKGROUND

Severe acute malnutrition contributes to 1 million deaths among children annually. Adding routine antibiotic agents to nutritional therapy may increase recovery rates and decrease mortality among children with severe acute malnutrition treated in the community.

METHODS

In this randomized, double-blind, placebo-controlled trial, we randomly assigned Malawian children, 6 to 59 months of age, with severe acute malnutrition to receive amoxicillin, cefdinir, or placebo for 7 days in addition to ready-to-use therapeutic food for the outpatient treatment of uncomplicated severe acute malnutrition. The primary outcomes were the rate of nutritional recovery and the mortality rate.

RESULTS

A total of 2767 children with severe acute malnutrition were enrolled. In the amoxicillin, cefdinir, and placebo groups, 88.7%, 90.9%, and 85.1% of the children recovered, respectively (relative risk of treatment failure with placebo vs. amoxicillin, 1.32; 95% confidence interval [CI], 1.04 to 1.68; relative risk with placebo vs. cefdinir, 1.64; 95% CI, 1.27 to 2.11). The mortality rates for the three groups were 4.8%, 4.1%, and 7.4%, respectively (relative risk of death with placebo vs. amoxicillin, 1.55; 95% CI, 1.07 to 2.24; relative risk with placebo vs. cefdinir, 1.80; 95% CI, 1.22 to 2.64). Among children who recovered, the rate of weight gain was increased among those who received antibiotics. No interaction between type of severe acute malnutrition and intervention group was observed for either the rate of nutritional recovery or the mortality rate.

CONCLUSIONS

The addition of antibiotics to therapeutic regimens for uncomplicated severe acute malnutrition was associated with a significant improvement in recovery and mortality rates. (Funded by the Hickey Family Foundation and others; ClinicalTrials.gov number, NCT01000298.).

Predicting mortality for paediatric inpatients where malaria is uncommon

OBJECTIVE

As the proportion of children living low malaria transmission areas in sub-Saharan Africa increases, approaches for identifying non-malarial severe illness need to be evaluated to improve child outcomes.

DESIGN

As a prospective cohort study, we identified febrile paediatric inpatients, recorded data using Integrated Management of Childhood Illness (IMCI) criteria, and collected diagnostic specimens.

SETTING

Tertiary referral centre, northern Tanzania.

RESULTS

Of 466 participants with known outcome, median age was 1.4 years (range 2 months-13.0 years), 200 (42.9%) were female, 11 (2.4%) had malaria and 34 (7.3%) died. Inpatient death was associated with: Capillary refill >3 s (OR 9.0, 95% CI 3.0 to 26.7), inability to breastfeed or drink (OR 8.9, 95% CI 4.0 to 19.6), stiff neck (OR 7.0, 95% CI 2.8 to 17.6), lethargy (OR 5.2, 95% CI 2.5 to 10.6), skin pinch >2 s (OR 4.8, 95% CI 1.9 to 12.3), respiratory difficulty (OR 4.0, 95% CI 1.9 to 8.2), generalised lymphadenopathy (OR 3.6, 95% CI 1.6 to 8.3) and oral candidiasis (OR 3.4, 95% CI 1.4 to 8.3). BCS <5 (OR 27.2, p<0.001) and severe wasting (OR 6.9, p<0.001) were independently associated with inpatient death.

CONCLUSIONS

In a low malaria transmission setting, IMCI criteria performed well for predicting inpatient death from non-malarial illness. Laboratory results were not as useful in predicting death, underscoring the importance of clinical examination in assessing prognosis. Healthcare workers should consider local malaria epidemiology as malaria over-diagnosis in children may delay potentially life-saving interventions in areas where malaria is uncommon.

Bacterial Isolates and Antibiotic Sensitivity among Gambian Children with Severe Acute Malnutrition

Background. Establishing the pattern of infection and antimicrobial sensitivities in the local environment is critical to rational use of antibiotics and the development of management algorithms. Methods. Morbidity history and physical examination of 140 children with severe acute malnutrition were recorded. Their blood, stool, and urine samples were cultured and antibiotic sensitivity patterns determined for any bacterial pathogens isolated. Results. Thirty-eight children had a pathogen isolated from blood culture, 60% of which were considered contaminants. Coagulase negative staphylococcus was the predominant contaminant, while the major causes of bacteraemia were nontyphoidal Salmonella (13%), S. pneumoniae (10%), and E. coli (8%). E. coli accounted for 58% of the urinary isolates. No pathogen was isolated from stool. In vitro sensitivity by disk diffusion showed that 87.5% of the isolates were sensitive to ampicillin and/or gentamicin and 84.4% (27/32) to penicillin and/or gentamicin. Conclusions. A combination of ampicillin and gentamicin provides adequate antibiotic cover for severely malnourished children in The Gambia.

Identification of Staphylococcus aureus: DNase and Mannitol salt agar improve the efficiency of the tube coagulase test

Background

The ideal identification of Staphylococcus aureus clinical isolates requires a battery of tests and this is costly in resource limited settings. In many developing countries, the tube coagulase test is usually confirmatory for S. aureus and is routinely done using either human or sheep plasma. This study evaluated Mannitol salt agar and the deoxyribonuclease (DNase) test for improving the efficiency of the tube coagulase test in resource limited settings. The efficiency of human and sheep plasma with tube coagulase tests was also evaluated.

Methods

One hundred and eighty Gram positive, Catalase positive cocci occurring in pairs, short chains or clusters were subjected to growth on Mannitol salt agar, deoxyribonuclease and tube coagulase tests. Of these, isolates that were positive for at least two of the three tests (n = 60) were used to evaluate the performance of the tube coagulase test for identification of S. aureus, using PCR-amplification of the nuc gene as a gold standard.

Results

Human plasma was more sensitive than sheep plasma for the tube coagulase test (sensitivity of 91% vs. 81% respectively), but both plasmas had very low specificity (11% and 7% respectively). The sensitivity and specificity of the tube coagulase test (human plasma) was markedly improved when Mannitol salt agar and DNase were introduced as a tri-combination test for routine identification of Staphylococcus aureus (100% specificity and 75% sensitivity). The specificity and sensitivity of Mannitol salt agar/DNase/tube coagulase (sheep plasma) combination was 100% and 67%, respectively.

Conclusion

The efficiency of the tube coagulase test can be markedly improved by sequel testing of the isolates with Mannitol salt agar, DNase and Tube coagulase. There is no single phenotypic test (including tube coagulase) that can guarantee reliable results in the identification of Staphylococcus aureus.

Community-acquired bloodstream infections in Africa: a systematic review and meta-analysis

Data on the prevalence and causes of community-acquired bloodstream infections in Africa are scarce. We searched three databases for studies that prospectively studied patients admitted to hospital with at least a blood culture, and found 22 eligible studies describing 58 296 patients, of whom 2051 (13.5%) of 15 166 adults and 3527 (8.2%) of 43 130 children had bloodstream infections. 1643 (29.1%) non-malaria bloodstream infections were due to Salmonella enterica (58.4% of these non-typhoidal Salmonella), the most prevalent isolate overall and in adults, and 1031 (18.3% overall) were due to Streptococcus pneumoniae, the most common isolate in children. Other common isolates included Staphylococcus aureus (531 infections; 9.5%) and Escherichia coli (412; 7.3%). Mycobacterium tuberculosis complex accounted for 166 (30.7%) of 539 isolates in seven studies that used mycobacterial culture techniques. HIV infection was associated with any bloodstream infection, particularly with S enterica and M tuberculosis complex bacteraemia. Where recorded, patients with bloodstream infections had an in-hospital case fatality of 18.1%. Our results show that bloodstream infections are common and associated with high mortality. Improved clinical microbiology services and reassessment of empirical treatment guidelines that account for the epidemiology of bloodstream infections might contribute to better outcomes.

Rhodococcus equi infection in HIV-infected individuals: case reports and review of the literature

Rhodococcus equi is a gram-positive, coryneform bacterium that causes zoonotic infection mainly in horses and foals. It sometimes affects humans presenting as cavitary pneumonia. Immunocompromised patients, including HIV-infected patients, are more susceptible to R. equi infection. We present 10 cases of R. equi infection in HIV-positive patients admitted to our institute from 1991 to June 2008. Moreover, we have reviewed 272 cases of R. equi infection in HIV-infected persons, published from 1986 through 2008. With respect to the literature data, the R. equi strains isolated in our case series showed lower sensitivity to ceftriaxone, amoxicillin/clavulanic acid, and cotrimoxazole. Prompt diagnosis, early initiation of antiretroviral treatment and combined antimicrobial treatment seem to be effective to eradicate the infection and to improve the outcome.

Molecular epidemiology of community-acquired invasive non-typhoidal Salmonella among children aged 2–29 months in rural Gambia and discovery of a new serovar, Salmonella enterica Dingiri

Sixty-two invasive non-typhoidal Salmonella (NTS) isolates from children aged 2–29 months in rural Gambia were examined for serovar prevalence and antimicrobial susceptibility, and characterized using multilocus sequence typing (MLST) of seven genes, aroC, dnaN, hemD, hisD, purE, sucA and thrA. Salmonella enterica serovar Enteritidis was the most common serovar (80.6  %), followed by S. enterica serovar Typhimurium (8.0  %). Thirty-three per cent of the isolates were resistant to all eight antimicrobials tested, including ampicillin (74.2  %), cotrimoxazole (64.5  %) and tetracycline (63  %). A total of 40.3  % of the NTS cases had an initial clinical diagnosis of malaria, whilst 27.3  % had a diagnosis of clinical pneumonia and 18  % had a diagnosis of septicaemia. MLST of NTS resulted in ten different sequence types (STs), of which five were novel, representing five different NTS serovars. In general, STs were restricted to the same serovar. One type (ST11) encompassed 80.6  % of the NTSs. A new NTS serovar named S. enterica serovar Dingiri was discovered. S. Dingiri was isolated from a 6-month-old male with an initial clinical diagnosis of malaria but a final clinical diagnosis of anaemia and septicaemia. S. Dingiri, which possesses an antigenic formula of 17:z:1,6, was sensitive to ampicillin, cefotaxime, chloramphenicol, ciprofloxacin, cotrimoxazole and tetracycline but resistant to gentamicin, and was ST338.

Population pharmacokinetics of a single daily intramuscular dose of gentamicin in children with severe malnutrition

OBJECTIVES

The World Health Organization recommends that all children admitted with severe malnutrition should routinely receive parenteral ampicillin and gentamicin; despite this, mortality remains high. Since this population group is at risk of altered volume of distribution, we aimed to study the population pharmacokinetics of once daily gentamicin (7.5 mg/kg) in children with severe malnutrition and to evaluate clinical factors affecting pharmacokinetic parameters.

METHODS

Thirty-four children aged 0.5-10 years were studied. One hundred and thirty-two gentamicin concentrations (median of four per patient), drawn 0.4-24.6 h after administration of the intramuscular dose, were analysed. The data were fitted by a two-compartment model using the population package NONMEM.

RESULTS

Gentamicin was rapidly absorbed and all concentrations measured within the first 2 h after administration were > 8 mg/L (indicating that satisfactory peak concentrations were achieved). Ninety-eight percent of samples measured more than 20 h after the dose were < 1 mg/L. The best model included weight, and it was found that high base deficit, high creatinine concentration and low temperature (all markers of hypovolaemic shock) reduced clearance (CL/F). Weight influenced volume of the central (V1/F) and peripheral (V2/F) compartments, and high base deficit reduced V2/F and intercompartmental CL (Q/F). Interindividual variability in CL was 26%, in V1/F 33% and in V2/F and Q/F was 52%. Individual estimates of CL/F ranged from 0.02 to 0.16 (median 0.10) L/h/kg and those of Vss/F from 0.26 to 1.31 (median 0.67) L/kg. Initial half-lives had a median of 1.4 h and elimination half-lives and a median of 14.9 h. Excessive concentrations were observed in one patient who had signs of renal impairment and shock.

CONCLUSIONS

Although a daily dose of 7.5 mg/kg achieves satisfactory gentamicin concentrations in the majority of patients, patients with renal impairment and shock may be at risk of accumulation with 24 hourly dosing. Further studies of gentamicin pharmacokinetics in this group are now needed to inform future international guideline recommendations.

Bacteraemia among severely malnourished children infected and uninfected with the human immunodeficiency virus-1 in Kampala, Uganda

BACKGROUND

To establish the magnitude of bacteraemia in severely malnourished children, and describe the types of bacteria and antimicrobial sensitivity by HIV status.

METHOD

Isolates were recovered from 76 blood specimens. Antibiotic susceptibility tests were performed using commercial antibiotic disks and demographic and clinical findings were recorded.

RESULTS

Of the 450 children 63% were male; median age 17.0 months (inter quartile range, IQR 12-24) and 57% had oedema. 151 (36.7 %) of 411 tested HIV-positive; 76 (17.1%) of 445 blood specimens grew bacterial isolates; 58% were Gram negative - S. typhimurium (27.6%) and S. enteriditis (11.8%). Staph. aureus (26.3%) and Strep. pneumoniae (13.2%) were the main Gram positive organisms. There was no difference in the risk of bacteraemia by HIV status, age < 24 months, male sex, or oedema, except for oral thrush (OR 2.3 CI 1.0-5.1) and hypoalbuminaemia (OR 3.5 CI 1.0-12.1). Isolates from severely immuno-suppressed children (CD4% <15%) were more likely to grow Salmonella enteriditis (OR 5.4; CI 1.6 - 17.4). The isolates were susceptible (> or = 80%) to ciprofloxacin, ceftriaxone and gentamicin; with low susceptibility to chlorampenicol, ampicillin (< 50%) and co-trimoxazole (<25%). Suspicion of bacteraemia had 95.9% sensitivity and 99.2% specificity. Among bacteraemic children, mortality was higher (43.5% vs 20.5%) in the HIV-positive; OR 3.0 (95%CI 1.0, 8.6).

CONCLUSION

Bacteraemia affects 1 in every 6 severely malnourished children and carries high mortality especially among the HIV-positive. Given the high level of resistance to common antibiotics, there is need for clinical trials to determine the best combinations of antibiotics for management of bacteraemia in severely malnourished children.

Blood culture contamination in Tanzania, Malawi, and the United States: a microbiological tale of three cities

We conducted retrospective, comparative analyses of contamination rates for cultures of blood obtained in the emergency rooms of Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania; Lilongwe Central Hospital (LCH) in central Malawi; and the Duke University Medical Center (DUMC) in the United States. None of the emergency room patients had indwelling intravascular devices at the time that the blood samples for cultures were obtained. In addition, we reviewed the contamination rates for a cohort of patients already hospitalized in the DUMC inpatient medical service, most of whom had indwelling intravascular devices. The bloodstream infection rates among the patients at MNH (n=513) and LCH (n=486) were similar (approximately 28%); the contamination rates at the two hospitals were 1.3% (7/513) and 0.8% (4/486), respectively. Of 54 microorganisms isolated from cultures of blood collected in the DUMC emergency room, 26 (48%) were identified as skin contaminants. Cultures of blood collected in the DUMC emergency room were significantly more likely to yield growth of contaminants than the cultures of blood collected in the emergency rooms at MNH and LCH combined (26/332 versus 11/1,003; P<0.0001) or collected in the DUMC inpatient medical service (26/332 versus 7/283; P<0.01). For the MNH and LCH blood cultures, lower contamination rates were observed when skin was disinfected with isopropyl alcohol plus tincture of iodine rather than isopropyl alcohol plus povidone-iodine. In conclusion, blood culture contamination was minimized in sub-Saharan African hospitals with substantially limited resources through scrupulous attention to aseptic skin cleansing and improved venipuncture techniques. Application of these principles when blood samples for culture are obtained in U.S. hospital emergency rooms should help mitigate blood culture contamination rates and the unnecessary microbiology workup of skin contaminants.

Nosocomial outbreak of extended-spectrum beta-lactamase-producing Salmonella isangi in pediatric wards

Since May 2000, extended-spectrum beta-lactamase-producing (ESBL) Salmonella Isangi were isolated from pediatric patients at a tertiary hospital. A total of 41 patients with positive cultures were reviewed, and the majority presented with gastroenteritis, fever, or both. One ESBL phenotype was noted in all isolates, and clonality was confirmed by pulsed-field gel electrophoresis. This is the first report of Salmonella sp. ESBL resistance in our hospital.

Human immunodeficiency virus infection and pediatric bacterial meningitis in developing countries

Over a million children are infected by the human immunodeficiency virus (HIV); most of whom live in the developing world. Bacterial meningitis is a serious infection of childhood that is 10 times more common in resource-constrained settings than well-resourced countries, and the outcome is worse. This paper reviews the relationship of bacterial meningitis to HIV infection and also the effect of HIV status on antibiotic sensitivity to common causes of childhood meningitis. The combined effects on outcome and long-term sequelae of meningitis are discussed and illustrated with results from Malawi and Southern Africa.

Staphylococcal skin infections in children: rational drug therapy recommendations

Staphylococcus aureus remains one of the most common and troublesome of bacteria causing disease in humans, despite the development of effective antibacterials and improvement in hygiene. The organism is responsible for over 70% of all skin and soft tissue infections in children and accounts for up to one-fifth of all visits to pediatric clinics. Skin and soft tissue infections that are predominantly caused by S. aureus include bullous and non-bullous impetigo, folliculitis, furunculosis, carbunculosis, cellulitis, surgical and traumatic wound infections, mastitis, and neonatal omphalitis. Other skin and soft tissue infections may also be caused by S. aureus but are often polymicrobial in origin and require special consideration. These include burns, decubitus ulcers (particularly in the perianal region), puncture wounds of the foot, as well as human and mammalian bites. Treatment of staphylococcal skin infections varies from topical antiseptics to prolonged intravenous antibacterials, depending on severity of the lesions and the health of the child. The treatment of choice for oral antibacterials remains the penicillinase-resistant penicillins such as flucloxacillin. Cefalexin and erythromycin are suitable cost-effective alternatives with broader cover, although care must be taken with the use of macrolides because of development of resistance to multiple families of antibacterials, particularly the lincosamides. Other cephalosporins such as cefadroxil and cefprozil are also effective, can be given once daily and have a better tolerability profile -- while azithromycin has a further advantage of a 3-day course. However, all of these agents are more expensive. Although the antibacterials have been given for 10 days in most clinical trials, there is no evidence that this duration is more effective than a 7-day course. In children requiring intravenous therapy, ceftriaxone has a major advantage over other antibacterials such as sulbactam/ampicillin and cefuroxime in that it can be given once daily and may, therefore, be suitable for outpatient treatment of moderate-to-severe skin infections. Newer-generation cephalosporins and loracarbef are also effective and have a broader spectrum of activity, but do not offer any added benefit and are significantly more expensive. Skin and soft tissue infections due to methicillin-resistant S. aureus (MRSA) are still relatively uncommon in children. Well children with community-acquired MRSA infections can be treated with clindamycin or trimethoprim-sulfamethoxazole (cotrimoxazole), but must be observed closely for potentially severe adverse effects. In severe infections, vancomycin remains the treatment of choice, while intravenous teicoplanin and clindamycin are suitable alternatives. Linezolid and quinupristin/dalfopristin are currently showing great promise for the treatment of multi-resistant Gram-positive infections. While the choice of antibacterial is important, supportive management, including removal of any infected foreign bodies, surgical drainage of walled-off lesions, and regular wound cleaning, play a vital role in ensuring cure.

Bacterial infections in children with HIV/AIDS

HIV/AIDS affects over 850,000 children in Africa. Bacterial infections are frequent in this group of children. Pneumonia, meningitis and septicaemia are especially common, recurrent and most often caused by Streptococcus pneumoniae. Salmonella spp are the most frequently isolated causative agent of septicaemia in malarial areas. Soft tissue, eye and oral infections have a higher incidence in HIV-infected than uninfected children. In all instances the causative agents are not dissimilar from those that cause disease in HIV-uninfected children, but the mortality is greater. Increased bacterial resistance to first line antibiotics has been reported and the use of cotrimoxazole prophylaxis may further influence the resistance pattern of common bacteria.

Isolation of Rhodococcus equi from the feces of indigenous animals and soil from the Lower Zambezi National Park and Lochinvar National Park, Zambia

Rhodococcus equi is an important pathogen in foals; however, its incidence in African indigenous animals is poorly understood. Fecal samples (92 from nine indigenous species) and 43 soil samples were collected from two Zambian National Parks. The presence of R. equi was investigated and 533 isolates were tested for the presence of 15- to 17-kDa antigens (VapA) and a 20-kDa antigen (VapB) by immunoblotting and PCR. R. equi was isolated (10(2)-10(4) colony forming units/g) from 75% of fecal and 74% of soil samples. Neither antigen was detected; however, about 20% of the isolates contained cryptic plasmids of various sizes. There was no evidence of virulent R. equi, but the avirulent form was widespread in the animals and the soil.

Clinical predictors of bloodstream infections and mortality in hospitalized Malawian children

BACKGROUND

In sub-Saharan Africa, bloodstream infections (BSI) are a major cause of pediatric mortality. Because of limited resources and facilities in these developing countries, treatment often must be based solely on clinical observations and patient history and includes the use of broad spectrum antimicrobials, a factor in the emergence of antibiotic resistance.

METHODS

During July 28 through August 18, 1998 we analyzed clinical, epidemiologic and microbiologic data from a cohort of 225 hospitalized children in Malawi, Africa, to determine clinical indices associated with the presence/absence of BSI and/or mortality for use in settings with minimal microbiologic laboratory and intensive care facilities.

RESULTS

BSI (n = 35 children) were associated with malnutrition, chronic cough, lethargy by history, lethargy on examination and oral thrush; 92% of children without these symptoms were BSI-negative. Mortality (21 of 173 children with known mortality status) was associated with malnutrition, lethargy on examination, prior receipt of antimalarials and acute decreased feeding. Of those with > or =2 of these indices 69% died; of those with <2 of the indices 94% survived. Infection with human immunodeficiency virus was not significantly related to either BSI or mortality status.

CONCLUSIONS

Malnutrition, but not HIV, was strongly related to both BSI and mortality. Assessment of these BSI and mortality indices at hospital admission provides rapid, cost-free indication of which children are most/least in need of empiric antimicrobial therapy or intensive observation, thereby maximizing appropriate use of antimicrobials and limited facilities while minimizing inappropriate antimicrobial usage.

Detection of bloodstream pathogens in a bacille Calmette-Guérin (BCG)-vaccinated pediatric population in Malawi: a pilot study

Children in Malawi receive bacille Calmette-Guérin (BCG) vaccination within the first 3 days of life. Thus, we hypothesized that Malawian children infected with the human immunodeficiency type 1 virus (HIV-1) might be particularly vulnerable to dissemination of the BCG Mycobacterium bovis strain with which they were vaccinated. Following informed consent by parents, we studied children admitted to a Malawi general hospital during the 1998 wet and dry seasons. Blood from cohorts of acutely ill children was cultured for bacteria, including mycobacteria, and fungi, and tested for anti-HIV-1 antibodies. It was shown that non-typhi Salmonella and Escherichia coli were the predominant bloodstream pathogens during the wet and dry seasons, and that bloodstream dissemination of the BCG M. bovis strain is uncommon in HIV-1-infected children who receive the BCG vaccine.

Community-acquired bacteremia among hospitalized children in rural central Africa

OBJECTIVE

To describe the epidemiology of community-acquired bacteremia in children admitted to a rural hospital in central Africa and to identify useful diagnostic signs or symptoms.

METHODS

On admission, a blood culture was obtained from all children admitted to Children's Hospital of Lwiro between 1989 and 1990. Clinical and biologic signs of infection and nutritional status were recorded.

RESULTS

Among the 779 children included in the study, 15.9% were bacteremic on admission. The rate of bacteremia was the highest among children with jaundice (20/56; 35.7%) and fever (119/487; 24.4%). In contrast, children with severe malnutrition had a lower rate of bacteremia (13.2%) than weight growth retarded or well-nourished children (19.5%) (P = 0.046). Fever was the most useful diagnostic criteria (sensitivity and negative predictive value of 96.0% and 97.8%, respectively) even in severely malnourished children (sensitivity and negative predictive value of 96.4% and 99.1%, respectively). Enterobacteriacea, mostly Salmonella spp, caused 73% of the bacteremia. There was a high rate of resistance to ampicillin and chloramphenicol among the responsible organisms. Only 31 (47.7%) of 65 bacteremic children responded to the combination of ampicillin and gentamicin. The presence of bacteremia on admission did not significantly increase the risk of morality during hospitalization (19.4% compared with 13.5%; P = 0.088). Age less than 12 months and jaundice were independent risk factors for deaths in bacteremic children.

CONCLUSIONS

Community-acquired bacteremia caused by multiresistant Enterobacteriacea is an important problem of hospitalized well-nourished and malnourished children in central Africa. Fever on admission is a sensitive diagnostic sign, even in malnourished children.

Nontyphoidal salmonella bacteremia and pneumonia as the initial manifestation of human immunodeficiency virus infection in a four-year-old child

This report describes the case of a 4-year-old human immunodeficiency virus (HIV)-infected girl with Salmonella typhimurium bacteremia and pneumonia. The girl presented with a history of fever for 1 month and mild pulmonary symptoms. Subsequent studies revealed previously undiagnosed HIV disease.

Pulmonary manifestations of HIV/AIDS in the tropics

The most significant pulmonary opportunistic infections in the tropics are TB and pneumococcal pneumonia. Guidelines for the diagnosis and management of these and other pulmonary manifestations of HIV are discussed. Ultimately, unless concerted efforts are made to treat underlying HIV infection in regions most devastated by AIDS, the impact of these diseases will continue to grow.

Morbidity among human immunodeficiency virus-1-infected and -uninfected African children

OBJECTIVE

To assess patterns of morbidity and associated factors in late infancy and early childhood among human immunodeficiency virus (HIV)-infected and -uninfected African children.

DESIGN

Prospective study.

SETTING

The Queen Elizabeth Central Hospital, Blantyre, Malawi.

PARTICIPANTS

Children with known HIV status from an earlier perinatal intervention trial were enrolled during the first year of life and followed to approximately 36 months of age.

OUTCOME MEASURES

Morbidity and mortality information was collected every 3 months by a questionnaire. A physical examination was conducted every 6 months. Blood to determine CD4(+) values was also collected. Age-adjusted and Kaplan-Meier analyses were performed to compare rates of morbidity and mortality among infected and uninfected children.

RESULTS

Overall, 808 children (190 HIV-infected, 499 HIV-uninfected but born to infected mothers, and 119 born to HIV-uninfected mothers) were included in this study. Of these, 109 died during a median follow-up of 18 months. Rates of childhood immunizations were high among all children (eg, lowest was measles vaccination [87%] among HIV-infected children). Age-adjusted morbidity rates were significantly higher among HIV-infected than among HIV-uninfected children. HIV-infected children were more immunosuppressed than were uninfected children. By 3 years of age, 89% of the infected children died, 10% were in HIV disease category B or C, and only approximately 1% were without HIV symptoms. Among HIV-infected children, median survival after the first occurrence of acquired immunodeficiency syndrome-related conditions, such as splenomegaly, oral thrush, and developmental delay, was <10 months. These same conditions, in addition to frequent bouts of fever, were the main morbidity predictors of mortality.

CONCLUSIONS

The frequency of diseases was high, and progression from asymptomatic or symptomatic HIV disease to death was rapid. Management strategies that effectively reduce morbidity for HIV-infected children are needed.

Rhodococcus equi and HIV-1 infection in Uganda

OBJECTIVES

To describe three cases of Rhodococcus equi infection in a cohort of HIV-1 infected adults in Entebbe, Uganda and to compare this to the rates and presentation of tuberculosis in this cohort.

METHODS

Consecutive HIV-1 infected adults registering with a community HIV/AIDS clinic in Entebbe were enrolled in a cohort between October 1995 and June 1998 as part of an intervention trial of pneumococcal polysaccharide vaccine. Participants were routinely reviewed every 6 months and had open access to the clinic when unwell. Standard protocols were followed for investigation and management of illness. Microbiological investigations followed standard procedures.

RESULTS

1372 (71% female) study participants were followed for 2141 person years of observation (pyo). Rhodococcus equi was isolated from three study participants from blood, a lymph node aspirate and stool. The individuals were undergoing investigation of acute pneumonia, acute cough with cervical lymphadenopathy and chronic fever with wasting, respectively. The clinical features of these cases are described. All had a CD4 T-cell count of <300/ml. The rate of R. equi infection in the cohort was 1.4/1000 pyo. There were 132 cases of pulmonary and extrapulmonary tuberculosis in the cohort which were diagnosed either microbiologically or clinically. The rate of laboratory confirmed mycobacterial disease was 50.1/1000 pyo. The ratio of mycobacterial disease to R. equi disease was 36:1 (95% CI 11-113:1).

CONCLUSIONS

Rhodococcus equi infection occurs in HIV-1 infected adults in Africa. The infection is clinically indistinguishable from pulmonary and extra-pulmonary tuberculosis in the cohort described here. Although the rate of R. equi disease is much less than that of tuberculosis, it is important to consider it in the differential diagnosis of tuberculous infection in cases which are smear negative. Rhodococcus equi infection is probably underdiagnosed in Africa due to a lack of microbiological facilities and its resemblance to common commensal organisms.

Bacterial infection in children with HIV: a prospective study from Cape Town, South Africa

Invasive bacterial infection in children infected with the human immunodeficiency virus (HIV) is common. South African data on this problem are limited. Over 1 year we prospectively studied 108 HIV-infected children hospitalized for 136 presumed infective episodes. Blood culture was positive in 24.8% of episodes. Streptococcus pneumoniae predominated (14/30 positive blood cultures); one-third of isolates showed resistance to penicillin. Acute lower respiratory tract infection accounted for 44% of clinical diagnoses, a bacterial cause being established for 23.8% of these. Age and stage of HIV infection did not influence the likelihood of a positive culture. A high proportion of presumed infective episodes requiring hospitalization of young HIV-infected children have a bacterial cause. Blood culture appears to be a useful method of obtaining the microbiological information required to focus antibiotic therapy.

Pneumococcal bacteremia during a decade in children in Soweto, South Africa

OBJECTIVES

To monitor for a decade the incidence and the clinical and microbiologic characteristics of pneumococcal bacteremia in children in Soweto and to assess the influence of HIV infection on any changes.

METHODS

Case records of children with pneumococcal bacteremia at Chris Hani Baragwanath Hospital from July, 1986, to June, 1987 (1986/ 1987), and from July, 1996, to June, 1997 (1996/ 1997), were retrospectively reviewed.

RESULTS

There were 194 episodes, 62 in 19861 1987 and 132 in 1996/1997. The minimum annual incidence for children younger than 5 years of age increased from 61 per 100000 (179 per 100000 for those <12 months old) in 1986/1987 to 130 per 100000 (349 per 100000 for those <12 months old) in 1996/1997. Sixty-seven (60%) of 111 patients tested in 1996/1997 were HIV-seropositive; none were tested in 1986/1987. The HIV-infected compared with HIV-noninfected were more likely to be malnourished (61% vs. 36%, P = 0.02), less likely to have other underlying disease (12% vs. 50%, P = 0.00001) and more frequently used antibiotics recently (69% vs. 43%, P = 0.008). Penicillin-nonsusceptible isolates were found in 22 (35%) patients in 1986/1987 and 52 (39%) in 1996/1997. There was no significant change in antimicrobial susceptibility during the decade or by HIV serostatus.

CONCLUSIONS

Children in Soweto had a high incidence of pneumococcal bacteremia which doubled during the decade mainly as a result of the impact of the HIV epidemic. There has been no significant change in antimicrobial susceptibility for the decade.

Clinical presentation of non-typhoidal Salmonella bacteraemia in Malawian children

We report the clinical presentation and outcome of 299 Malawian children with non-typhoidal Salmonella (NTS) bacteraemia and no evidence of focal sepsis, admitted to Queen Elizabeth Central Hospital (QECH), Blantyre, over a 26-month period (February 1996-April 1998). A peak incidence during the rainy season was noted. Salmonella typhimurium (79%) and S. enteritidis (13%) were the commonest isolates. For children aged > 6 months, NTS bacteraemia was significantly associated with malarial parasitaemia (RR 1.5 [1.2, 2.2], P < 0.01) and with severe anaemia (RR 7.2 [3.4, 15.3], P < 0.0001), when compared to other common pathogens causing childhood bacteraemia. Clinical overlap with malaria and anaemia, and the presence of malarial parasitaemia on admission, may delay diagnosis. NTS bacteraemia was commonly diagnosed following blood transfusion. Resistance in vitro to ampicillin (79%), co-trimoxazole (72%) and gentamicin (55%) was very common, and was rare to chloramphenicol (0.3%) which is the antibiotic of choice for NTS sepsis at QECH. Overall mortality was high (23%). Young age and clinical HIV infection were risk factors for mortality. Recurrences of NTS bacteraemia following antibiotic therapy were common among children with clinical HIV infection.

Bacteremia in febrile Malawian children: clinical and microbiologic features

BACKGROUND

There are no published data for the incidence or etiology of childhood bacteremia in Malawi. We describe the clinical and microbiologic features of children admitted to hospital from whom blood cultures yielded bacterial pathogens.

METHODS

Any neonate or child admitted to the pediatric wards of the Queen Elizabeth Central Hospital had a blood culture taken in the event of fever without obvious clinical explanation. Clinical and microbiologic data were prospectively collected for children with a significant positive culture.

RESULTS

Between September, 1996, and August, 1997, we processed 2,123 cultures. Of these, 365 (17.2%) grew a pathogen. Non-typhi salmonellae (NTS) and enteric Gram-negative bacilli constituted 67.4% of isolates, and Streptococcus pneumoniae constituted 16.4%. More than two-thirds of NTS episodes coincided with the peak malaria transmission season (January to June); 67% of bacteremic children were malnourished, 28% severely so. Patients with NTS bacteremia were significantly more likely to have coincident malaria and to have splenomegaly and anemia than children with other infecting organisms. The overall mortality was 38% but varied considerably according to age and nutritional status. Prior antibiotic use, coincident malaria or meningitis did not adversely affect outcome. In vitro resistance to the commonly available antibiotics ampicillin and trimethoprim-sulfamethoxazole was found in 76 and 71% of NTS isolates. Screening tests for penicillin resistance suggested a rate of 21% among pneumococci.

CONCLUSIONS

Bacteremia is common in hospitalized Malawian children and has a high mortality. There are high rates of resistance to some of the commonly used antibacterial agents.

Gram-negative bacillary bacteremia in human immunodeficiency virus type 1-infected children

BACKGROUND

HIV-infected children are particularly susceptible to serious bacterial infections including Gram-negative bacillary bacteremia (GNB). However, the information available on GNB in these children is limited.

METHODS

Retrospective review of hospital charts of HIV-infected children with GNB diagnosed between 1980 and 1997. The association between bacteremic episodes, degree of immunosuppression, HIV severity, medical treatment and clinical outcome was assessed.

RESULTS

Of 680 HIV-infected children, 72 (10.6%) had 95 episodes of GNB. Statistical analyses were restricted to data from the first episode. The mean age (+/-SD) at diagnosis of GNB was 2.5 +/- 2.7 years (median, 1.6). The predominant organisms were Pseudomonas aeruginosa (26.4%), nontyphoidal Salmonella (15.3%), Escherichia coli (15.3%) and Haemophilus influenzae (12.5%). The relative frequency, per 5-year interval, of P. aeruginosa bacteremia steadily increased from 13% during 1980 through 1984 to 56% during 1995 through 1997. There were no cases of H. influenzae bacteremia after January 1, 1990. Eighty percent of GNB developed in children with AIDS and 72.2% developed in those with severe immunosuppression. Hypogamma-globulinemia and neutropenia were present in only 4.9 and 10.4% of first episodes, respectively. The overall case-fatality rate of GNB was 43.0%, and in children younger than 12 months it was 54.2%.

CONCLUSIONS

A diagnosis of AIDS and/or severe immunosuppression was associated with increased risk of GNB, especially among younger children. Because of the high mortality of GNB, a broad spectrum antimicrobial therapy that effectively covers these organisms should be promptly instituted when bacteremia is suspected in HIV-infected children.

Pseudomonas spp. complications in patients with HIV disease: an eight-year clinical and microbiological survey

Two hundred and twenty-four episodes of Pseudomonas spp. complications that occurred in 179 consecutive patients with HIV infection were retrospectively reviewed. Pseudomonas spp. organisms were responsible for 11.6% of 1933 episodes of non-mycobacterial bacterial diseases (5.4% of 1072 episodes of sepsis), observed over an 8-year period; 20.7% of patients experienced disease relapses (45 episodes). These complications mostly involved lower airways (66 cases), urinary tract (53 episodes), and blood (34 cases), with Pseudomonas aeruginosa isolated in 161 episodes, and other Pseudomonas spp. in the remaining 63 cases. An advanced HIV disease was frequently present (as expressed by a prior diagnosis of AIDS, a low CD4+ lymphocyte count, and leukopenia-neutropenia). Indwelling intravascular and urinary catheters were often associated with bacteremia and urinary tract involvement, respectively. More than 60% of patients were given antibiotics and/or cotrimoxazole in the month preceding the onset of Pseudomonas spp. disease. Bacterial strains isolated from our HIV-infected patients showed a favorable sensitivity to piperacillin, ceftazidime, imipenem, amikacin, tobramycin, and ciprofloxacin. An adequate antimicrobial treatment led to clinical and microbiological cure in 73.2% of patients at the first episode, and in 22.3% more subjects after one or more relapses. A lethal outcome occurred in only eight patients of 179 (4.5%), suffering from a far advanced HIV disease; P. aeruginosa infection directly contributed to death in four cases (sepsis, and/or pneumonia). Nosocomial disease occurred in 46.4% of the 224 episodes, and was significantly related to a previous diagnosis of AIDS, concurrent neutropenia, the occurrence of sepsis or urinary tract infection, disease relapses, the involvement of non-aeruginosa Pseudomonas spp., and a lethal outcome, compared with community-acquired infection. Our experience (the largest reported to date) confirms that Pseudomonas spp. (including non-aeruginosa Pseudomonas spp. organisms) is responsible for remarkable morbidity and mortality among patients with HIV infection, and may pose relevant problems to clinicians and microbiologists involved in the care of HIV-infected patients.

Typhoid fever and HIV infection: a rare disease association in industrialized countries

Typhoid fever is still a global health problem, mainly in tropical and subtropical areas of the world and in developing countries, where relatively elevated morbidity and mortality rates still are present, mostly because of persisting poor hygienic conditions. In the majority of Mediterranean regions, including Italy, the disease is constantly present, though with a low prevalence rate, as a result of an endemic persistence of Salmonella typhi infection.1-4 On the other hand, in industrialized countries, most cases of S. typhi infection are related to foreign travel or prior residence in endemic countries.4-6 In the United States, 2445 cases of typhoid fever have been reported in the decade 1985 to 1994, and the annual number of cases remained relatively stable over time: over 70% of episodes were acquired in endemic countries (mostly Mexico and India).6 The persisting morbidity of S. typhi also may be supported by the increasing resistance rate of this pathogen against a number of commonly used antimicrobial compounds. For instance, 6% of 331 evaluable S. typhi strains were resistant to ampicillin, chloramphenicol, and cotrimoxazole, and 22% of isolates were resistant to at least one of these three agents in a recent survey performed in the United States.6 The spread of antibiotic resistance among S. typhi isolates is emerging in many countries, and multidrug-resistant strains have been isolated, as well as isolates with poor susceptibility to fluoroquinolones,3-5,7-9 so that in vitro susceptibility should be determined for all cultured strains, and antimicrobial treatment should be adjusted accordingly. Nevertheless, fluoroquinolones (e.g., ciprofloxacin and pefloxacin) or third-generation cephalosporins, still represent the best choice for empirical treatment,2,4,6-8,10 and mortality remains rare in Western countries (less than 1% of episodes), although it is expected to be greater in developing areas of the world. The aim of this report is to describe two cases of typhoid fever that occurred in patients with human immunodeficiency virus (HIV) infection, a rarely reported disease association in industrialized countries.

Bacteraemia complicating severe malaria in children

Bacteraemia associated with severe malaria in childhood is a sporadically reported phenomenon but its incidence and clinical importance are unknown. We have reviewed clinical and laboratory data from 783 Kenyan children sequentially admitted with a primary diagnosis of severe malaria. The overall incidence of bacteraemia in children with severe malaria was 7.8% (95% CI 5.5-10.0); however, in children under 30 months of age the incidence was 12.0% (95% CI 8.3-15.7). The presence of bacteraemia was associated with a 3-fold increase in mortality (33.3% vs. 10.4%, P < 0.001). We conclude that invasive bacterial disease may contribute to the pathophysiology of the clinical syndrome of severe malaria in an important subgroup of children. We recommend that young children with severe malaria be treated with broad-spectrum antibiotics in addition to antimalarial drugs.