The changing burden of pediatric bloodstream infections in Calgary, Canada, 2000-2006

Community-acquired Staphylococcus aureus bacteremia in healthy children-13 years of experience in a pediatric tertiary center

Staphylococcus aureus (SA) is an important pathogen in the pediatric population. Community-acquired SA bacteremia (SAB) may also occur in healthy individuals, yet literature on this matter is scarce. Our study aims to describe patient characteristics, clinical course, and outcomes of healthy children with SAB. This retrospective cohort study included all healthy patients aged 3 months-18 years, with a positive SA blood culture taken during the first 72 hours of hospitalization between 2009 and 2021. Demographic, laboratory, and clinical data were collected. Analysis was performed to assess factors associated with complicated disease. Fifty-seven patients aged 8.5 ± 4.5 years were included. Forty-one (71.9%) were males and 18 (31.6%) reported trauma before onset. Thirty-four (59.6%) were diagnosed with osteomyelitis, 14 (24.6%) with abscesses, 7 (12.3%) with isolated SAB, and 7 (12.3%) suffered from complex SAB. Factors associated with abscess formation were age ≥ 13 years and groin pain; OR 3.857 (p-value 0.01) and 20.0 (p-value 0.01), respectively. A CRP ≥ 13 mg/dL upon admission was found to be a predictor of complex disease (AUC of 0.765; 95% CI 0.559-0.971 (p-value 0.024)). Higher odds for complex SAB were seen in persistent bacteremia, prolonged time to eradication, and time to targeted therapy; OR 5.833 (p-value 0.048), OR 1.810 (p-value 0.017), and OR 3.214 (p-value 0.015), respectively. There were no cases of mortality.

CONCLUSION

This study describes various aspects of SAB in healthy children and could help to better recognize the signs and symptoms of the disease. Moreover, we report several indicators that may assist clinicians in identifying at-risk patients for a complicated disease.

WHAT IS KNOWN

•SAB is an important pediatric disease that can cause severe complications and mortality. •SAB is well described as a nosocomial infection and in high-risk populations such as premature babies, children with intravascular devices, immunodeficient individuals, and other major chronic illnesses. However, data regarding community-acquired SAB in healthy children is lacking.

WHAT IS NEW

•This is the first study to exclusively include previously healthy children with community-acquired SAB. •Higher CRP upon admission, persistent bacteremia, and longer time to targeted therapy are all in correlation with complications such as multifocal disease, sepsis, ICU admission, and endocarditis.

Trends in Enterobacterales Bloodstream Infections in Children

OBJECTIVES

Enterobacterales bloodstream infections (E-BSI) cause a significant burden of disease in children and are associated with antimicrobial resistance. We assessed temporal changes in the population-based incidence of E-BSI in children in Queensland, Australia.

METHODS

We conducted a cohort study of incidents of E-BSI occurring in children in Queensland between 2000 and 2019, with a total population of 19.7 million child years. Infections were linked to clinical outcomes in hospital admissions and vital statistics databases. We estimated age- and sex-standardized E-BSI incidence rates over time. Secondary outcomes included the proportion of extended-spectrum β-lactamase phenotypes per year, hospital length of stay, and mortality.

RESULTS

We identified 1980 E-BSI in 1795 children. The overall age- and sex-standardized incidence rate was 9.9 cases per 100 000 child years, which increased from 7.3 to 12.9 over the period studied, an increase of 3.9% (95% confidence interval: 3.1-4.7) per year. There were 3.6 cases of E. coli bloodstream infection per 100 000 child years, increasing annually by 4.7% (3.5-5.9). The Salmonella sp. bloodstream infection incidence was 3.0 cases per 100 000 child years, which increased from 2013 by 13.7% (3.8-24.3) per year. The proportion of extended-spectrum β-lactamase E. coli increased over time. Mortality and length of stay were higher among children with comorbidities than those without (4.0% vs 0.3%, and 14 vs 4 days, respectively, P < .001).

CONCLUSIONS

The age- and sex-standardized incidence of E-BSI almost doubled in Queensland children over 2 decades, driven by increases in Salmonella sp. and E. coli. Increasing resistance of E. coli should prompt the inclusion of children in antimicrobial clinical trials.

Exploring Acute Febrile Illness in Children: Clinical Characteristics and Diagnostic Challenges

Background Pediatric febrile illnesses are a major cause of hospital admissions and are often associated with significant morbidity and mortality. These illnesses pose a diagnostic challenge to both clinicians and laboratories. This study aims to explore the clinical characteristics of acute febrile illness in children and examine the effectiveness of various diagnostic techniques. Methods This prospective study was carried out at the Mahatma Gandhi Memorial Hospital, Warangal, India, from January 2020 to October 2022. It included children aged one month to 12 years. Results Out of 245 identified cases, 195 met the inclusion criteria. This study found that 18 patients (9.23%) suffered from serious bacterial infections (SBIs). In 63 patients (32.20%), the source of infection remained unidentified. Among those with SBI, UTIs were the most frequent. Bacteremia was identified in 2.5% of the patients. Conclusion SBIs were identified in 18 hospitalized children (9.23%), with UTIs being the most common SBI in children aged one to 36 months. Children in this age group presenting with toxic symptoms should be thoroughly evaluated for SBIs. The study also observed a higher prevalence of Gram-negative bacteremia compared to Gram-positive cases.

Antimicrobial treatment duration for uncomplicated bloodstream infections in critically ill children: a multicentre observational study

Background

Bloodstream infections (BSIs) cause significant morbidity and mortality in critically ill children but treatment duration is understudied. We describe the durations of antimicrobial treatment that critically ill children receive and explore factors associated with treatment duration.

Methods

We conducted a retrospective observational cohort study in six pediatric intensive care units (PICUs) across Canada. Associations between treatment duration and patient-, infection- and pathogen-related characteristics were explored using multivariable regression analyses.

Results

Among 187 critically ill children with BSIs, the median duration of antimicrobial treatment was 15 (IQR 11–25) days. Median treatment durations were longer than two weeks for all subjects with known sources of infection: catheter-related 16 (IQR 11–24), respiratory 15 (IQR 11–26), intra-abdominal 20 (IQR 14–26), skin/soft tissue 17 (IQR 15–33), urinary 17 (IQR 15–35), central nervous system 33 (IQR 15–46) and other sources 29.5 (IQR 15–55) days. When sources of infection were unclear, the median duration was 13 (IQR 10–16) days. Treatment durations varied widely within and across PICUs. In multivariable linear regression, longer treatment durations were associated with severity of illness (+ 0.4 days longer [95% confidence interval (CI), 0.1 to 0.7, p = 0.007] per unit increase in PRISM-IV) and central nervous system infection (+ 17 days [95% CI, 6.7 to 27.4], p = 0.001). Age and pathogen type were not associated with treatment duration.

Conclusions

Most critically ill children with BSIs received at least two weeks of antimicrobial treatment. Further study is needed to determine whether shorter duration therapy would be effective for selected critically ill children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03219-z.

Paediatric community-acquired bacteraemia, pneumococcal invasive disease and antibiotic resistance fell after the pneumococcal conjugate vaccine was introduced

AIM

This study examined the impact of the routine pneumococcal conjugate vaccination (PCV) on childhood community-acquired bacteraemia (CAB) and antibiotic resistance patterns in Israeli children.

METHODS

Israel added the PCV vaccine to its national immunisation programme in July 2009. We retrospectively analysed the medical records of all patients with CAB under 18 years at three children's hospitals in Tel Aviv and Jerusalem from 2007 to 2015. The microbiological data, clinical presentation, pneumococcal serotype distribution, antibiotic susceptibility and outcomes of infections were compared before and after the vaccine was introduced.

RESULTS

There were 511 904 emergency department visits and 125 922 children were hospitalised. Of those, 238 had CAB before vaccination was introduced (mean age 17 months) and 316 had CAB after the introduction (mean age 21 months). Emergency department presentations for CAB fell from 141.8 to 91.8 per 100 000 visits: a relative risk reduction (RRR) of 35%. Hospitalisations for CAB decreased from 430 to 337 per 100 000 admissions: an RRR of 22%. Hospitalisations due to Staphylococcus aureus increased significantly and penicillin nonsusceptible blood Streptococcus pneumoniae isolates decreased significantly.

CONCLUSION

Introducing national pneumococcal conjugate vaccination significantly changed the epidemiology of CAB, with reduced antibiotic-resistant Streptococcus pneumoniae and increased hospitalisation rates for Staphylococcus aureus infections.

Pediatric bloodstream infections in metropolitan Australia

BACKGROUND

Bloodstream infections (BSIs) cause significant morbidity and mortality of children worldwide. The aim of this study was to investigate BSI in children and determine the identity of causative organism and their susceptibility patterns in a metropolitan public hospital in Australia.

METHODS

We retrospectively reviewed children aged 0-16 years admitted to a public hospital from January 1, 2010 to August 31, 2014 inclusive, and whose blood cultures revealed bacteraemia. Data were collected regarding patient demographics, species of bacteria isolated, antimicrobial susceptibility of these isolates, and clinical outcomes.

RESULTS

Out of 96 patients with BSI, 55 (57.3%) were males. The median age was 3.35 years (IQR 0.44-7.46), and there were 2 mortalities. Common sites of infection were the respiratory tract (16.6%, n = 16), bone and joints (15.6%, n = 15) and the urinary tract (11.5%, n = 11). The most frequent isolates were Staphylococcus aureus (27.0%), Escherichia coli (14.0%) and Streptococcus pneumoniae (12.0%). Whilst most bacterial isolates displayed susceptibility (> 90%) to common antimicrobial agents, only 57.1% (8/14) of Escherichia coli isolates were susceptible to ampicillin and 58.3% (7/12) were susceptible to co-trimoxazole.

CONCLUSIONS

Gram-positive bacteria accounted for the majority of pediatric BSIs, of which invasive pneumococcal disease remains a noteworthy cause. The majority of isolates, except Escherichia coli, were susceptible to commonly used antimicrobials. This study confirms the knowledge of high rates of resistance of Escherichia coli to ampicillin. Therefore, empirical treatment should still include gentamicin. Monitoring of resistance patterns is warranted to ensure that antibiotic therapy remains appropriate.

Using risk adjustment to improve the interpretation of global inpatient pediatric antibiotic prescribing

Objectives

Assessment of regional pediatric last-resort antibiotic utilization patterns is hampered by potential confounding from population differences. We developed a risk-adjustment model from readily available, internationally used survey data and a simple patient classification to aid such comparisons.

Design

We investigated the association between pediatric conserve antibiotic (pCA) exposure and patient / treatment characteristics derived from global point prevalence surveys of antibiotic prescribing, and developed a risk-adjustment model using multivariable logistic regression. The performance of a simple patient classification of groups with different expected pCA exposure levels was compared to the risk model.

Setting

226 centers in 41 countries across 5 continents.

Participants

Neonatal and pediatric inpatient antibiotic prescriptions for sepsis/bloodstream infection for 1281 patients.

Results

Overall pCA exposure was high (35%), strongly associated with each variable (patient age, ward, underlying disease, community acquisition or nosocomial infection and empiric or targeted treatment), and all were included in the final risk-adjustment model. The model demonstrated good discrimination (c-statistic = 0.83) and calibration (p = 0.38). The simple classification model demonstrated similar discrimination and calibration to the risk model. The crude regional pCA exposure rates ranged from 10.3% (Africa) to 67.4% (Latin America). Risk adjustment substantially reduced the regional variation, the adjusted rates ranging from 17.1% (Africa) to 42.8% (Latin America).

Conclusions

Greater comparability of pCA exposure rates can be achieved by using a few easily collected variables to produce risk-adjusted rates.

Changes in the Nature and Severity of Invasive Pneumococcal Disease in Children Before and After the Seven-valent and Thirteen-valent Pneumococcal Conjugate Vaccine Programs in Calgary, Canada

BACKGROUND

Since the introduction of childhood pneumococcal conjugate vaccines, invasive pneumococcal disease (IPD) incidence has decreased in children and the predominant serotypes causing disease have changed. This study describes changes in the clinical features of IPD in children (<18 years) before and after the conjugate vaccine introduction.

METHODS

The Calgary Area Streptococcus pneumoniae Epidemiology Research study collects information on all IPD cases in Calgary, Alberta, Canada. Descriptive and regression analyses were used to compare IPD in the pre-vaccine (January 2000 to August 2002), post-7-valent protein-polysaccharide conjugate vaccine (September 2002 to June 2010) and post-13-valent protein-polysaccharide conjugate vaccine (PCV13) (July 2010 to December 2015) periods; intensive care unit and inpatient admissions were outcome measures.

RESULTS

The incidence of IPD in children (<18 years) decreased from an average of 17 cases/100,000/yr in 2000-2001 to 4 cases/100,000/yr in 2015. The median age of children presenting with IPD shifted from 2.0 years (interquartile range: 2.5) in the pre-vaccine period to 3.9 years (interquartile range: 6.2) in the post-PCV13 period. The proportion of children with a comorbidity that is an indication for pneumococcal vaccination did not change. Invasive disease with focus (meningitis, pneumonia, empyema, peritonitis) compared with invasive disease with bacteremia only increased from 44.6% in pre-vaccine to 64.0% and 61.4% in the post-7-valent protein-polysaccharide conjugate vaccine and post-PCV13 periods, respectively (P = 0.017). Having IPD in the post-PCV13 period compared with the pre-vaccine period was associated with an increased odds of hospitalization [Odds ratio (OR): 2.9; 95% Confidence Interval (CI): 1.4-6.2].

CONCLUSIONS

Clinical features of IPD have changed since pneumococcal conjugate vaccines were introduced, with a shift toward more focal infections requiring hospitalization. Although overall IPD cases have declined, disease that does occur appears to be more severe.

Staphylococcus aureus bacteraemia and endocarditis - epidemiology and outcome: a review

PURPOSE

To review the epidemiology of Staphylococcus aureus bacteraemia (SAB) and endocarditis (SAE), and discuss the short- and long-term outcome.  Materials and methods: A literature review of the epidemiology of SAB and SAE.

RESULTS

The reported incidence of SAB in Western countries is 16-41/100,000 person-years. Increasing incidence has been observed in many regions, in Iceland by 27% during 1995-2008. The increase is believed to depend on changes in population risk factors and possibly better and more frequent utilization of diagnostic procedures. S. aureus is now the leading causes of infective endocarditis (IE) in many regions of the world. It accounts for 15-40% of all IE cases, and the majority of cases in people who inject drugs (PWID). Recently, the incidence of SAE in PWID in Stockholm, Sweden, was found to be 2.5/1000 person-years, with an in-hospital mortality of 2.5% in PWID as compared to 15% in non-drug users. The 30-day mortality associated with SAB amounts to 15-25% among adults in Western countries, but is lower in children (0-9%). Mortality associated with SAE is high (generally 20-30% in-hospital mortality), and symptomatic cerebral embolizations are common (12-35%). The 1-year mortality reported after SAB and SAE is 19-62% and reflects deaths from underlying diseases and complications caused by the infection. In a subset of SAE cases, valvular heart surgery is needed (15-45%), but active intravenous drug use seems to be a reason to refrain from surgery. Despite its importance, there are insufficient data on the optimal management of SAB and SAE, especially on the required duration of antibiotic therapy.  Conclusions: The epidemiology of SAB and SAE has been changing in the past decades. They still carry a substantial morbidity and mortality. Intensified studies on treatment are warranted for improving patient outcome.

Rapid replacement by non-vaccine pneumococcal serotypes may mitigate the impact of the pneumococcal conjugate vaccine on nasopharyngeal bacterial ecology

There is growing concern that interventions that alter microbial ecology can adversely affect health. We characterised the impact of the seven-valent pneumococcal conjugate vaccine (PCV7) on pneumococcal carriage and the bacterial component of the nasopharyngeal microbiome during infancy. Newborns were recruited into three groups as follows: Group1 (n = 33) was the control group and comprised infants who received PCV7 after 6 months and came from unvaccinated communities. Group 2 (n = 30) came from unvaccinated communities and Group 3 (n = 39) came from vaccinated communities. Both group 2 and 3 received PCV7 at 2, 3 and 4 months. Culture and 16 S rRNA gene sequencing were performed on nasopharyngeal specimens collected at regular intervals from infants. Nasopharyngeal carriage of PCV7 serotypes in Group 1 was significantly higher than in Group 2 and 3 (p < 0.01). However, pneumococcal carriage remained comparable due to an expansion of non-vaccine serotypes in Groups 2 and 3. Determination of phylogenetic dis(similarities) showed that the bacterial community structures were comparable across groups. A mixed effects model showed no difference in community richness (p = 0.15) and Shannon α-diversity (p = 0.48) across the groups. Immediate replacement of pneumococcal vaccine serotypes with non-vaccine serotypes may mitigate the impact of PCV7 on nasopharyngeal bacterial community structure and ecology.

Patterns and trends of pediatric bloodstream infections: a 7-year surveillance study

We characterize the epidemiology of pediatric bloodstream infections (BSIs) in Switzerland. We analyzed pathogen distribution and resistance patterns in monomicrobial and polymicrobial BSIs in children from 2008 to 2014 using data from the Swiss antibiotic resistance centre (ANRESIS). A confirmatory statistical analysis was performed comparing pathogens and resistance across 20 acute care hospitals. We identified 3,067 bacteremia episodes, of which 1,823 (59 %) were considered true BSI episodes. Overall, S. aureus (16.5 %, 300) was the most frequent pathogen, followed by E. coli (15.1 %, 276), coagulase-negative staphylococci (CoNS, 12.9 %, 235), S. pneumoniae (11.1 %, 202) and non-E. coli Enterobacteriaceae (8.7 %, 159). S. aureus and E. coli showed similar frequencies in all of the variables analyzed (e.g., hospital acquisition, hospital type, medical specialty). The proportion of these microorganisms did not change over time, resistance rates remained low (4.3 % methicillin resistance in S. aureus; 7.3 % third-/fourth-generation cephalosporin resistance in E. coli), and no significant resistance trends were observed. We observed a 50 % increase of CoNS BSIs from 2008 (9.8 %, 27) to 2014 (15.2 %, 46, p value for trend = 0.03). S. pneumoniae decreased from 17.5 % (48) to 6.6 % (20) during that timeframe (p for trend = 0.007). S. aureus and E. coli remained the most significant pathogens among pediatric BSIs in Switzerland, exhibiting low resistance rates. CoNS accounted for a greater proportion of BSIs over time. The decrease in bacteremic pneumococcal infections can likely be attributed to the introduction of the 13-valent conjugate vaccine in 2011.

Clinical and microbiological features of resistant gram-negative bloodstream infections in children

BACKGROUND

Bloodstream infections (BSIs) caused by Gram-negative (GN) bacteria cause significant morbidity and mortality. There is a worldwide increase in the reported incidence of resistant microorganisms; therefore, surveillance programs are important to define resistance patterns of GN microorganisms causing BSIs. The objective of this study was to describe the clinical and microbiological features of resistant GN BSIs in a tertiary pediatric hospital in Turkey.

METHODS

Patients between 1 month and 18 years of age hospitalized between January 2005 and December 2012 were included in this study. The presence of ESBL and AmpC type beta-lactamase activity were evaluated using the Clinical and Laboratory Standards Institute (CLSI) disk diffusion and double-disk synergy tests.

RESULTS

A total of 209 resistant GN bacterial BSI episodes were identified in 192 patients. Of 192 children, 133 (69.2%) were aged ≤48 months of age. Sixty-six (31.6%) of the BSIs were considered community-acquired and 143 (68.4%) were hospital-acquired infections. The most common isolates were non-fermenting GN bacteria (n=117, 55.9%). The major causative pathogens were Pseudomonas spp. in non-fermenting GN bacteria. The resistance rates to imipenem for Pseudomonas spp. and Acinetobacter spp. were 40.5% and 41.6%, respectively. The most common isolates in fatal patients were Pseudomonas spp. followed by Escherichia coli. The overall 28-day mortality rate was 16.3%.

CONCLUSIONS

Although our study was performed at a single center and represents a local population, based on this study, it is concluded that surveillance programs and studies of novel antibiotics for resistant GN bacteria focusing on pediatric patients are required.

Quantifying the Burden of Hospital-Acquired Bloodstream Infection in Children in England by Estimating Excess Length of Hospital Stay and Mortality Using a Multistate Analysis of Linked, Routinely Collected Data

BACKGROUND

Hospital-acquired bloodstream infection (HA-BSI) is associated with substantial morbidity, mortality, and healthcare costs in all patient populations. Young children have been shown to have a high rate of healthcare-associated infections compared with the adult population. We aimed to quantify the excess mortality and length of stay in pediatric patients from HA-BSI.

METHODS

We analyzed data collected retrospectively from a probabilistically linked national database of pediatric (aged 1 month-18 years) in-patients with a microbiologically confirmed HA-BSI in England between January and March 2009. A time-dependent Cox regression model was fit to determine the presence of any effect. Furthermore, a multistate model, adjusted for the time to onset of HA-BSI, was used to compare outcomes in patients with HA-BSI to those without HA-BSI. We further adjusted for patients' characteristics as recorded in hospital admission data.

RESULTS

The dataset comprised 333 605 patients, with 214 cases of HA-BSI. After adjustment for time to HA-BSI and comorbidities, the hazard for discharge (dead or alive) from hospital for patients with HA-BSI was 0.9 times (95% confidence interval [CI], .8-1.1) that of noninfected patients. Excess length of stay associated with all-cause HA-BSI was 1.6 days (95% CI, .2-3.0), although this duration varied by pathogen. Patients with HA-BSI had a 3.6 (95% CI, 1.3-10.4) times higher hazard for in-hospital death than noninfected patients.

CONCLUSIONS

Hospital-acquired bloodstream infection increased the length of stay and mortality of pediatric inpatients. The results of this study provide an evidence base to judge the health and economic impact of programs to prevent and control HA-BSI in children.

The aetiology of paediatric bloodstream infections changes after pneumococcal vaccination and group B streptococcus prophylaxis

AIM

This study explored the incidence and aetiology of bloodstream infections after patients received the pneumococcal conjugate vaccination and a risk-based intrapartum antibiotic prophylaxis against early onset sepsis caused by group B streptococcus. We also monitored clinically relevant antimicrobial resistance.

METHOD

We studied 3986 positive blood cultures from children up to 17 years of age at a paediatric hospital in Stockholm, Sweden, using data from medical records before and after the initiatives, to reduce early onset sepsis, were introduced in 2007 and 2008.

RESULTS

Bloodstream infections caused by Streptococcus pneumoniae declined by 42% overall (5.6 to 3.2/100 000) and by 62% in previously healthy children under 36 months of age (24.2 to 9.2/100 000). Early onset sepsis caused by group B streptococcus declined by 60% (0.5 to 0.2/1000 live born children). Bacterial meningitis caused by these bacteria decreased by 70%. Staphylococcus aureus and various Gram-negative bacteria became the dominant pathogens, in both previously healthy children and those with underlying disease. Overall, antimicrobial resistance remained low between the two 5-year study periods.

CONCLUSION

Pneumococcal conjugate vaccination and risk-based intrapartum antibiotic prophylaxis against group B streptococcus effectively decreased the incidence of bloodstream infections. Empirical antibiotic therapy should target Staphylococcus aureus in both community and hospital-acquired invasive bacterial infections.

Antibiotic Resistance Prevalence in Routine Bloodstream Isolates from Children's Hospitals Varies Substantially from Adult Surveillance Data in Europe

BACKGROUND

Surveillance of antimicrobial resistance (AMR) is central for defining appropriate strategies to deal with changing AMR levels. It is unclear whether childhood AMR patterns differ from those detected in isolates from adult patients.

METHODS

Resistance percentages of nonduplicate Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa bloodstream isolates from children less than 18 years of age reported to the Antibiotic Resistance and Prescribing in European Children (ARPEC) project were compared with all-age resistance percentages reported by the European Antimicrobial Resistance Surveillance Network (EARS-Net) for the same pathogen-antibiotic class combinations, period and countries. In addition, resistance percentages were compared between ARPEC isolates from children less than 1 year of age and children greater than or equal to1 year of age.

RESULTS

Resistance percentages for many important pathogen-antibiotic class combinations were different for ARPEC isolates compared with EARS-Net. E. coli and K. pneumoniae fluoroquinolone resistance percentages were substantially lower in ARPEC (13.4% and 17.9%) than in EARS-Net (23.0% and 30.7%), whereas the reverse was true for all pathogen-antibiotic class combinations in P. aeruginosa (for example, 27.3% aminoglycoside resistance in ARPEC, 19.3% in EARS-Net, 32.8% carbapenem resistance in ARPEC and 20.5% in EARS-Net), and for S. pneumoniae and macrolide resistance. For many Gram-negative pathogen-antibiotic class combinations, isolates from children greater than or equal to 1 year of age showed higher resistance percentages than isolates from children less than 1 year of age.

CONCLUSIONS

Age-stratified presentation of resistance percentage estimates by surveillance programs will allow identification of important variations in resistance patterns between different patient groups for targeted intervention.

Population-based epidemiology and microbiology of community-onset bloodstream infections

Bloodstream infection (BSI) is a major cause of infectious disease morbidity and mortality worldwide. While a positive blood culture is mandatory for establishment of the presence of a BSI, there are a number of determinants that must be considered for establishment of this entity. Community-onset BSIs are those that occur in outpatients or are first identified <48 h after admission to hospital, and they may be subclassified further as health care associated, when they occur in patients with significant prior health care exposure, or community associated, in other cases. The most common causes of community-onset BSI include Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Antimicrobial-resistant organisms, including methicillin-resistant Staphylococcus aureus and extended-spectrum β-lactamase/metallo-β-lactamase/carbapenemase-producing Enterobacteriaceae, have emerged as important etiologies of community-onset BSI.

Paediatric bacteraemias in tropical Australia

AIM

Bacteraemias in children are an important cause of morbidity and mortality. Knowledge of local epidemiology and trends is important to inform practitioners of likely pathogens in the sick child. This study aimed to determine trends over time in pathogenic organisms causing paediatric bacteraemia in North Queensland and to audit a hospital's blood culture results with respect to contamination rate.

METHODS

This was a retrospective review of 8385 blood cultures collected from children attending a tertiary centre in North Queensland over a 10-year period (2001-2010).

RESULTS

There were 696 positive blood cultures (8.3%) with 70 different bacterial species detected. Gram-positive and Gram-negative bacteria accounted for 48.6% and 51.4% of isolates, respectively. Overall, bacteraemia accounted for 4.7 per 1000 admissions. The rate of contamination was 60.6% among positive blood cultures and 5.0% for all blood cultures sampled. These results were compared with previous published reports. Notable differences were seen in the frequencies of Salmonella and group A Streptococcus bacteraemias in North Queensland when compared with other reports. There was also a decline in vaccine-preventable infections such as S. pneumoniae and an increasing trend of community-acquired MRSA bacteraemia.

CONCLUSION

This study has demonstrated the unique profile of causative pathogens of paediatric bacteraemias in tropical Australia. In light of the increasing prevalence of MRSA, empiric treatment for sepsis for children in this region needs to be reconsidered.

Low mortality of Staphylococcus aureus bacteremia in Icelandic children: nationwide study on incidence and outcome

BACKGROUND

Staphylococcus aureus is a major cause of blood stream infections, but population-based studies on pediatric S. aureus bacteremia (SAB) are sparse. The objective of the study was to evaluate the incidence and mortality of SAB in Icelandic children over time, and to assess the proportions of nosocomial and health-care-associated infections.

METHODS

Children <18 years with positive blood cultures for S. aureus from January 1995 through December 2011 were identified retrospectively at the clinical microbiology laboratories performing blood cultures in Iceland. Clinical data were collected from medical records.

RESULTS

In total, 140 children had 146 distinct episodes of SAB. Bacteremia-related mortality was 0.7% (1/146), all-cause 30-day mortality, 1.4% (2/146), and 1-year mortality, 3.6% (5/140). The annual incidence of SAB was 10.9/100,000 children, decreasing by 36% from 13.1/100,000 in 1995-2003 to 8.4/100,000 in 2004-2011 (P < 0.001). At the same time the annual number of blood cultures analyzed at the main study site decreased from 1529 to 1143 (25%). SAB incidence was highest in infants (<1 year), 58.8/100,000. Of 146 episodes 50 (34%) were nosocomial, 21 (14%) health-care associated and 75 (51%) community acquired. No methicillin-resistant S. aureus isolate was identified.

CONCLUSIONS

In this nationwide study on pediatric SAB, the case fatality ratio was very low. A decreasing incidence was seen, possibly related to fewer blood cultures being collected. Nosocomial and health-care-associated infections accounted for 50% of the cases. The findings provide useful information on the epidemiology and outcome of SAB in children.

Timing of positive blood samples does not differentiate pathogens causing healthcare-associated from community-acquired bloodstream infections in children in England: a linked retrospective cohort study

Paediatricians recognize that using the time-dependent community-acquired vs. hospital-acquired bloodstream infection (BSI) dichotomy to guide empirical treatment no longer distinguishes between causative pathogens due to the emergence of healthcare-associated BSIs. However, paediatric epidemiological evidence of the aetiology of BSIs in relation to hospital admission in England is lacking. For 12 common BSI-causing pathogens in England, timing of laboratory reports of positive paediatric (3 months to 5 years) bacterial blood isolates were linked to in-patient hospital data and plotted in relation to hospital admission. The majority (88·6%) of linked pathogens were isolated <2 days after hospital admission, including pathogens widely regarded as hospital acquired: Enterococcus spp. (67·2%) and Klebsiella spp. (88·9%). Neisseria meningitidis, Streptococcus pneumoniae, group A streptococcus and Salmonella spp. were unlikely to cause hospital-acquired BSI. Pathogens commonly associated with hospital-acquired BSI are being isolated <2 days after hospital admission alongside pathogens commonly associated with community-acquired BSI. We confirm that timing of blood samples alone does not differentiate between bacterial pathogens. Additional factors including clinical patient characteristics and healthcare contact should be considered to help predict the causative pathogen and guide empirical antibiotic therapy.

Superior sensitivity and decreased time to detection with the Bactec Peds Plus/F system compared to the BacT/Alert Pediatric FAN blood culture system

Here, we compare the sensitivities and times to detection (TTD) of BacT/Alert Pediatric FAN (PF) and Bactec Peds Plus blood culture bottles. Test bottles were inoculated with 2 ml of banked whole blood, 1-ml aliquots of antibiotic suspension, and organisms diluted to simulate a bacteremia level of 10 to 100 CFU/ml. The control bottles were inoculated with 3 ml of banked blood and organism suspensions only. The organism-drug combinations were Staphylococcus epidermidis and vancomycin, methicillin-resistant Staphylococcus aureus and vancomycin, Streptococcus pneumoniae, vancomycin, and ceftriaxone, Streptococcus agalactiae, ampicillin, and cefotaxime, Escherichia coli, cefotaxime, and cefepime, Pseudomonas aeruginosa, piperacillin-tazobactam, cefepime, and gentamicin, Neisseria meningitidis and ceftriaxone, and Haemophilus influenzae and ceftriaxone. The control and test bottle combinations were tested in duplicate. The bottles were incubated for 5 days; 32 control and 104 test bottles were incubated. Overall, the bacterial recovery rates for the PF and Peds Plus bottles were 37% and 62%, 94% and 100% in the controls, 19% and 50% in the test bottles, and 33% and 92% in the bottles with vancomycin, respectively. No bacteria were recovered from the bottles with S. pneumoniae, S. agalactiae, E. coli, N. meningitidis, or H. influenzae in combination with cefotaxime or ceftriaxone. The Peds Plus system detected P. aeruginosa in bottles with cefepime and piperacillin-tazobactam, but the PF system recovered bacteria only in bottles with trough levels of piperacillin-tazobactam. The mean TTD were shorter in the Peds Plus system controls (14.2 versus 18.0 h; P = 0.001) and the test bottles (14.3 versus 17.8 h; P = 0.008) than in the PF bottles. Overall, we demonstrated superior sensitivity, TTD, and antibiotic neutralization in the Bactec Peds Plus system compared to those in the Pediatric FAN system.

Community-acquired, healthcare-associated and hospital-acquired bloodstream infection definitions in children: a systematic review demonstrating inconsistent criteria

BACKGROUND

Historically, bacterial infections were categorized as either community-acquired (CA) or hospital-acquired (HA). However, the CA/HA dichotomy no longer adequately reflects patterns of emerging healthcare-associated (HCA) infections in complex patients managed between hospital and the community. Studies trying to define this evolving epidemiology often excluded children.

AIM

To identify what criteria have been used to distinguish between CA, HCA and HA bloodstream infections (BSIs) in children, and the proportional distribution of CA, HCA and HA among total BSIs and by organism.

METHODS

We systematically reviewed published literature from PubMed, UK Department of Health and US Centers for Disease Control and Prevention websites.

FINDINGS

Results from 23 studies and the websites highlighted the use of inconsistent criteria. There were 13 and 15 criteria variations for CA and HA BSI respectively, although a 48h cut-off for cultures sampled post admission was most commonly reported. Five studies used variable clinical criteria to define HCA. The mean proportion of paediatric CA BSI in nine studies was 50%. Only four BSI organisms from five studies were predominantly CA (Streptococcus pneumoniae, Salmonella spp.) or HA (coagulase-negative staphylococci, Enterococcus spp.), whereas Pseudomonas spp., Klebsiella spp. and Enterobacter spp. did not clearly fit into either category.

CONCLUSIONS

Our study reveals inconsistent use of criteria, and a lack of evidence upon which to base them, to distinguish between CA, HCA and HA BSI in children. Criteria for CA, HCA and HA BSI need to be developed using population-based studies that consider patients' clinical characteristics, recent healthcare exposure as well as isolated organism species.

Risk-adjusted monitoring of blood-stream infection in paediatric intensive care: a data linkage study

PURPOSE

National monitoring of variation in the quality of infection control in paediatric intensive care units (PICUs) requires comparisons of risk-adjusted rates. To inform the development of a national monitoring system, we evaluated the effects of risk-adjustment and outcome definition on comparisons of blood-stream infection (BSI) rates in PICU, using linkage of risk-factor data captured by national audit (PICANet) with laboratory records of BSI.

METHODS

Admission data for two children's hospitals 2003-2010 were extracted from PICANet and linked using multiple identifiers with laboratory BSI records. We calculated trends of PICU-acquired BSI, defined as BSI occurring between at least 2 days after admission until up to 2 days following discharge. In one PICU, we compared rates of all PICU-acquired BSI with clinically significant PICU-acquired BSI submitted to the national surveillance system.

RESULTS

Of 20,924 admissions, 1,428 (6.8 %) were linked to 1,761 PICU-acquired BSI episodes. The crude incidence rate-ratio for PICU-acquired BSI between PICUs was 1.15 [95 % confidence interval (CI) 1.05-1.26] but increased to 1.26 (1.14-1.39) after risk-adjustment. Rates of PICU-acquired BSI were 13.44 (95 % CI 12.60-14.28) per 1,000 bed-days at PICU 1 and 18.05 (95 % CI 16.80-19.32) at PICU 2. Of PICU-acquired BSI at PICU 2, 41 % was classified as clinically significant. Rates of PICU-acquired BSI decreased by 10 % per year between 2003 and 2010 for skin organisms and 8 % for non-skin organisms.

CONCLUSIONS

Risk-adjustment and standardisation of outcome measures are essential for fair comparisons of BSI rates between PICUs. Linkage of risk-factor data and BSI surveillance is feasible and could allow national risk-adjusted monitoring.

Age and risk factors influence the microbial aetiology of bloodstream infection in children

AIM

To study the aetiology of bloodstream infections (BSI) in children 0-17 years, the influence of age and underlying co-morbidity on BSI rate, distribution of pathogens and outcome; and to provide data on antimicrobial susceptibility patterns.

METHODS

A retrospective population-based study. Data on blood cultures were collected at yearly intervals during 1998-2008. Information about risk factors, focal infection and outcome was retrieved from the patient charts.

RESULTS

We identified 1097 BSI. The incidence of BSI was 0.4/1000. The age-specific incidence was 2.3/1000 in neonates (0-28 days old) and 0.2/1000 in the age group 6-17 years. Staphylococcus aureus was the most common pathogen. The number of species causing BSI in previously healthy children was lower compared with children with co-morbidity. Most children requiring intensive care had a serious underlying illness. Antimicrobial resistance was rare and did not influence outcome. The case-fatality rate was 14.4% in neonates, 5.4% in children with co-morbidity and 1.7% in previously healthy children.

CONCLUSION

Mortality from BSI is low, and a limited spectrum of pathogens is isolated from previously healthy children compared with children with co-morbidity. When choosing empirical therapy for suspected BSI, age and presence of risk factors should be taken into account.

Exploring the Epidemiology of Hospital-Acquired Bloodstream Infections in Children in England (January 2009-March 2010) by Linkage of National Hospital Admissions and Microbiological Databases

BACKGROUND

Hospital-acquired bloodstream infection (HA-BSI) requires immediate effective antibiotic treatment. However, there are no published national data for England that describe the pathogen profile and antibiotic resistance rates of HA-BSI in children.

METHODS

Probabilistic matching methods were used to link national data on microbiologically confirmed BSI to hospital in-patient admissions data for the period of January 2009-March 2010. HA-BSI was defined as a positive blood culture drawn from a child aged 1 month-18 years 2 or more days after admission (and before discharge).

RESULTS

A total of 8718 episodes of BSI was reported during the study period. Linkage allowed 82% of records to be matched, of which 23% (1734) were HA-BSI, giving a rate of 4.74 per 1000 admissions. The median age of infection was 1 year, and 54% of infections were in males. Methicillin resistance was seen in 83% and 17% of coagulase-negative staphylococci and Staphylococcus aureus, respectively. Penicillin resistance was rare in pyogenic streptococci but more common in viridans streptococci (39%). Among Gram-positive organisms, only 3% were vancomycin-resistant. The overall proportion of Gram-negative bacteria resistant to recommended empirical antibiotics (meropenem or piperacillin/tazobactam) was 5% and 16%, respectively, but <4% of isolates were resistant when either of these drugs were combined with gentamicin.

CONCLUSIONS

This study provides the first national estimates of the proportion of pediatric BSI that is hospital-acquired and describes the antimicrobial resistance of organisms causing infection. Pediatric HA-BSI remains unacceptably high; interventions must focus on identifying effective means of preventing HA-BSI, fostering antibiotic stewardship, and improving surveillance.

Presentation and management of pediatric orbital cellulitis

BACKGROUND

Orbital cellulitis is a serious, vision-threatening infection.

OBJECTIVE

To review the epidemiology and clinical data of pediatric orbital cellulitis in Manitoba.

METHODS

A 12-year retrospective review was conducted of all children (younger than 18 years of age) with orbital cellulitis admitted to Manitoba's only tertiary pediatric centre. Admission rates for orbital cellulitis were compared over three distinct time periods, based on licensure and funding levels of the heptavalent pneumococcal conjugate vaccine (PCV7) in Manitoba.

RESULTS

Thirty-eight patients with orbital cellulitis were identified. Of these, 11% were of Aboriginal ethnicity in contrast with 30% to 40% of children who were admitted for other respiratory illnesses. Subperiosteal abscesses occurred in 31.5%. Only eight patients (21%) required surgery. Follow-up imaging after presentation usually did not indicate a need for subsequent surgical drainage. The mean number of orbital cellulitis cases per 1000 admissions for the following periods - before PCV7 licensure, after licensure and before full provincial funding, and after licensure and full funding - were 0.39, 0.53 and 0.90, respectively. No significant difference was noted among any of the periods as PCV7 coverage increased.

CONCLUSIONS

The rate of subperiosteal abscesses was lower than other reports. This may be due to the median age at presentation. In contrast to admissions for most other respiratory infections at the Winnipeg Children's Hospital (Winnipeg, Manitoba), Aboriginal ethnicity was uncommon. Surprisingly, rates of admissions for orbital cellulitis appeared to show an increasing trend with increasing access to PCV7 in Manitoba, although overall the number of cases was very small. Studies into the changing microbiology of orbital cellulitis and sinusitis are warranted.

Staphylococcus aureus bloodstream infections in children: A population-based assessment

BACKGROUND

Although Staphylococcus aureus is a major cause of bloodstream infections, population-based data on these infections in children are limited.

OBJECTIVE

To describe the epidemiology of S aureus bacteremia in children.

METHODS

Population-based surveillance for all incident S aureus bacteremias was conducted among children (18 years of age or younger) living in the Calgary Health Region (Alberta) from 2000 to 2006.

RESULTS

During the seven-year study, 120 S aureus bloodstream infections occurred among 119 patients; 27% were nosocomial, 18% health care associated and 56% community acquired. The annual incidence was 6.5/100,000 population and 0.094/1000 live births. A total of 52% had a significant underlying condition, and this was higher for nosocomial cases. Bone and joint (40%), bacteremia without a focus (33%), and skin and soft tissue infections (15%) were the most common clinical syndromes. Infections due to methicillin-resistant S aureus were uncommon (occurring in one infection) and three patients (2.5%) died.

CONCLUSIONS

S aureus bacteremia is an important cause of morbidity in the paediatric age group. Underlying medical conditions and implanted devices are important risk factors. Methicillin-resistant S aureus and mortality rates are low.

Pneumococcus infections: is the burden still as heavy?

The death rate of invasive pneumococcal infections decreased by 100 fold in one century. This tremendous improvement was due mainly to antibiotic use and multiple attempts at antipneumococcal vaccinations; thus, this was true only for developed countries. However, in France, the incidence has increased, over the last 10 years, in all age classes except for children vaccinated by the heptavalent pneumococcal conjugate vaccine. The incidence of these infections remains high, when associated to some risk factors such as HIV infection, malignant blood diseases, solid cancers, bronchial diseases, or alcohol abuse. The pneumococcal vaccine should be prescribed first to patients with those risk factors. A change of serotypes distribution has been observed in children with a decrease of vaccine serotypes and predominance of related or non-vaccine serotypes. This reflects the effectiveness of vaccination and the need of to regularly update the vaccine. Thus, pneumococcal infections have been increasing and vaccination should be more widely proposed.

The association of emergency department crowding and time to antibiotics in febrile neonates

OBJECTIVES

The objective was to assess the relationship between emergency department (ED) crowding and timeliness of antibiotic administration to neonates presenting with fever in a pediatric ED.

METHODS

This was a retrospective cohort study of febrile neonates (aged 0-30 days) evaluated for serious bacterial infections (SBIs) in a pediatric ED from January 2006 to January 2008. General linear models were used to evaluate the association of five measures of ED crowding with timeliness of antibiotic administration, controlling for patient characteristics. A secondary analysis was conducted to determine which part of the ED visit for this population was most affected by crowding.

RESULTS

A total of 190 patients met inclusion criteria. Mean time to first antibiotic was 181.7 minutes (range = 18-397 minutes). At the time of case presentation, the number of patients waiting in the waiting area, total number of hours spent in the ED by current ED patients, number of ED patients awaiting admission, and hourly boarding time were all positively associated with longer times to antibiotic. The time from patient arrival to room placement exhibited the strongest association with measures of crowding.

CONCLUSIONS

Emergency department crowding is associated with delays in antibiotic administration to the febrile neonate despite rapid recognition of this patient population as a high-risk group. Each component of ED crowding, in terms of input, throughput, and output factors, was associated with delays. Further work is required to develop processes that foster a more rapid treatment protocol for these high-risk patients, regardless of ED crowding pressures.

Epidemiology and outcome of Gram-negative bloodstream infection in children: a population-based study

Population-based studies of Gram-negative bloodstream infection (BSI) in children are lacking. Therefore, we performed this population-based investigation in Olmsted County, Minnesota, to determine the incidence rate, site of acquisition, and outcome of Gram-negative BSI in children aged ⩽18 years. We used Kaplan-Meier method and Cox proportional hazard regression for mortality analysis. We identified 56 unique children with Gram-negative BSI during the past decade. The gender-adjusted incidence rate of Gram-negative BSI per 100 000 person-years was 129·7 [95% confidence interval (CI) 77·8-181·6]) in infants, with a sharp decline to 14·6 (95% CI 6·0-23·2) and 7·6 (95% CI 4·3-10·9) in children aged 1-4 and 5-18 years, respectively. The urinary tract was the most commonly identified source of infection (34%) and Escherichia coli was the most common pathogen isolated (38%). Over two-thirds (68%) of children had underlying medical conditions that predisposed to Gram-negative BSI. The overall 28-day and 1-year all-cause mortality rates were 11% (95% CI 3-18) and 18% (95% CI 8-28), respectively. Younger age and number of underlying medical conditions were associated with 28-day and 1-year mortality, respectively. Nosocomial or healthcare-associated acquisition was associated with both 28-day and 1-year mortality.

Epidemiology of pediatric community-acquired bloodstream infections in a children hospital in Paris, France, 2001 to 2008

In 2001 to 2008, we documented 483 cases of pediatric community-acquired bacteremia mostly because of Streptococcus agalactiae (< 4 days), Escherichia coli (4 days to 3 months), pneumococci (3 months to 5 years), and Staphylococcus aureus (> 5 years). Pneumococcal conjugate vaccination affected the serotype distribution of pneumococcal bacteremia but not its frequency. Serotype 19A represented 12% and 22% of pneumococci in the prevaccine and vaccine periods, respectively.

The changing aetiology of paediatric bacteraemia in England and Wales, 1998–2007

Bacteraemia in children is a potentially life-threatening condition. The objective of this study was to determine trends in the aetiology of bacteraemia in children aged 1 month–15 years in England and Wales by collecting data voluntarily reported by National Health Service hospital microbiology laboratories. Over the 10-year period 1998–2007, a total of 51 788 bacteraemia cases involving 105 genera/species of bacteria were reported. Total annual reports of bacteraemia increased from 4125 to 6916, with a mean increase of 6.5 % per year (95 % CI: 1.3–12.1 %). In 2007, just over half the cases were accounted for by four groups of organisms: coagulase-negative staphylococci (28 %), Staphylococcus aureus (10 %), non-pyogenic streptococci (9 %) and Streptococcus pneumoniae (7 %). These organisms along with a further 13 species/genera accounted for 90 % of the cases. The commonest Gram-negative organisms were Neisseria meningitidis and Escherichia coli, which each accounted for 5 % of total bacteraemia reports in 2007. There was a significant decrease in reports of bacteraemia due to the three vaccine-preventable pathogens Haemophilus influenzae, N. meningitidis and Strep. pneumoniae, following the introduction of each vaccine programme or catch-up campaign. This study identified the commonest causes of bacteraemia in children in England and Wales, and highlighted the shifts in trends observed over time.

The effect of routine vaccination on invasive pneumococcal infections in Canadian children, Immunization Monitoring Program, Active 2000-2007

Active surveillance was conducted by the 12 centers of the Canadian Immunization Monitoring Program, Active from 2000-2007 in children 16 years of age and younger to determine the influence of 7-valent pneumococcal conjugate immunization programs on the prevalence, serotype and antibiotic resistance patterns of invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae. The absolute number of reported IPD cases decreased 48% (p<0.01) over the 8-year period and 56% (p<0.01) in children 0-4 years of age. The absolute number of reported IPD cases caused by serotypes in the conjugate vaccine decreased 87.5% (p<0.01) overall and 92% (p<0.01) in children 0-4 years. Although 6 non-vaccine serotypes increased over time, only serotype 19A increased significantly (p<0.01). Overall, the proportion of penicillin resistant isolates remained unchanged at 17%. Cefotaxime/ceftriaxone resistance remained unchanged at 2% of isolates annually. Universal pneumococcal conjugate infant immunization programs have dramatically decreased cases of invasive pneumococcal disease.