Protocol for a randomised controlled trial of continuous infusions of vancomycin to improve the attainment of target vancomycin levels in young infants: The VANC trial

INTRODUCTION

Vancomycin is frequently used in the treatment of late-onset sepsis in young infants and is routinely administered as intermittent infusions (IIV); however, existing IIV dosing guidelines achieve target vancomycin levels in less than half of infants. Continuous infusions of vancomycin (CIV) are an attractive alternative as adult studies report a higher attainment of target vancomycin levels, simpler drug monitoring and fewer drug side effects.

METHODS

This is a multicentre, randomised controlled trial in which 200 young infants (aged 0-90 days) requiring vancomycin will be randomised to CIV or IIV for a duration determined by the treating clinician. Vancomycin levels will be measured immediately after the first dose in both arms. Trough and peak levels will be determined in the IIV arm and steady-state levels 18-30 hours after commencement of infusion will be measured in the CIV arm. Full blood count, urea and electrolytes, and C reactive protein level will be monitored throughout treatment. For all Gram-positive bacteria isolated from blood culture, a vancomycin Etest will be done to determine the minimum inhibitory concentration of the bacterium.

ANALYSIS

Primary outcome: the proportion of infants with levels within target range at their first steady-state concentration.

SECONDARY OUTCOMES

(1) the proportion of drug-related adverse effects; (2) the time to achieve target levels in the blood; (3) the pharmacodynamics of vancomycin (using non-linear mixed effect modelling).

ETHICS AND DISSEMINATION

The study has been approved by The Royal Children's Hospital Melbourne Human Research Ethics Committee (HREC) (No. 34030) and the South Eastern Sydney Local Health District HREC (SSA 16/G/335). Results will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02210169.

Pneumococcal haemolytic uraemic syndrome in the postvaccine era

OBJECTIVE

Pneumococcal infection is a leading cause of haemolytic uraemic syndrome (HUS) and is potentially vaccine preventable. Published data suggest high mortality and poor renal outcomes. The introduction of the 7-valent pneumococcal conjugate vaccine (PCV) has seen the emergence of disease caused by non-vaccine strains, particularly 19A. We sought to describe serotype prevalence and outcomes, particularly after the introduction of the 13-valent PCV.

DESIGN AND SETTING

We performed a retrospective chart review, using hospital medical records to identify cases of HUS in a tertiary paediatric hospital in Australia over a 20-year period (January 1997-December 2016). Associated pneumococcal infection was identified, and serotype data were categorised according to vaccine era: prevaccine (January 1997-December 2004), PCV7 (January 2005-June 2011) and PCV13 (July 2011-December 2016).

RESULTS

We identified 66 cases of HUS. Pneumococcal infection was proven in 11 cases, representing 4% (1/26) of cases prior to the introduction of PCV7, 20% (3/15) in the PCV7 era and 28% (7/25) in the PCV13 era. Subtype 19A was the most prevalent pneumococcal serotype (6/11). All four patients who received PCV7 were infected with a non-vaccine serotype. Four of the five patients who received PCV13 were classed as vaccine failures. Median follow-up was 14 (range 1-108) months. Chronic kidney disease was the most common complication (4/7). We observed no mortality, neurological sequelae or progression to end-stage kidney disease.

CONCLUSIONS

Serotype 19A is most commonly associated with pneumococcal HUS, despite the introduction of the 13-valent vaccine. Chronic kidney disease is a significant complication of pneumococcal HUS.

Adequate or Inadequate? The Volume of Blood Submitted for Blood Culture at a Tertiary Children's Hospital

The volume of blood sampled for culture critically influences the results. This study aimed to determine (1) the volume of blood submitted for culture, (2) the proportion of blood cultures with adequate volume, (3) whether measured improvement from a previous educational intervention had been sustained, and (4) the impact of blood volume on culture result. The volume of blood submitted for cultures was determined over a 13-month period by weighing bottles before and after collection and before and after an educational intervention. The volume of blood submitted in 5127 culture bottles were measured. Fewer than 50% of all cultures were deemed adequate. A significant pathogen was isolated in 4.7% of blood cultures, and low-volume cultures were more likely to yield contaminant isolates (47/2422 [1.9%] vs 22/2705 [0.8%], P = .0005). Subsequently, the higher rate of contaminant isolates from low-volume cultures may affect selection and rationalization of antibiotic therapy.

Adverse effects of amphotericin B in children; a retrospective comparison of conventional and liposomal formulations

AIMS

Lipid formulations of amphotericin B, rather than conventional amphotericin (c-amB), are increasingly used despite limited data comparing these preparations in children. Data on the incidence of adverse effects with amphotericin B at standard doses are scarce. This study aimed to compare the adverse effects associated with standard doses of c-amB and liposomal amphotericin (l-amB) in children.

METHODS

Children admitted to the Royal Children's Hospital Melbourne and treated with c-amB or l-amB between January 2010 and September 2013 were included. Clinical and laboratory data were retrospectively extracted from medical records to compare amphotericin-related infusion reactions, nephrotoxicity (glomerulotoxicity and tubulopathy) and hepatotoxicity.

RESULTS

Seventy-six children received c-amB and 39 received l-amB. Standard drug administration (recommended dose and infusion time) occurred in 74% (56/76) of patients on c-amB and 85% (33/39) on l-amB. In these 89 children, infusion-related reactions were similar for both c-amB and l-amB (23% (13/56) vs. 9% (3/33); P = 0.15); none occurred in children aged <90 days. There was no difference in amphotericin-associated glomerulotoxicity (c-amB 14% (8/56) vs. l-amB 21% (7/33); P = 0.40) or in the median maximum potassium requirements (c-amB 3.1 vs. l-amB 2.3 mmol kg^-1  d^-1 ; P = 0.29). Hepatotoxicity occurred more frequently with l-amB than c-amB (83% (24/29) vs. 56% (20/36); P = 0.032).

CONCLUSIONS

When appropriately administered, l-amB was associated with more hepatotoxicity than c-amB, with no difference in infusion-related reactions or nephrotoxicity. Differences in adverse effects between the preparations is not as marked in children as reported in adults.

The controversial role of breast milk in GBS late-onset disease

Group B streptococcus (GBS) is one of the most common causes of neonatal sepsis and meningitis. Intra-partum antibiotic prophylaxis does not play a significant role in reducing the risk of GBS late-onset disease. One of the proposed mechanisms for GBS late-onset disease is infection through contaminated breast milk. Infants in whom breast milk is thought to be the source for GBS late-onset disease are more heavily colonised and reports suggest they have a higher recurrence rate compared to infants with other potential sources. There is no consensus whether the breast milk of mothers of infants with GBS late-onset disease, especially those with recurrent episodes, should be tested for GBS. In addition, recommendations differ on whether breast-feeding should be interrupted or breast milk pasteurised, or whether the mother and infant should be treated for colonisation. In this review we discuss these different approaches.

Australia-wide point prevalence survey of the use and appropriateness of antimicrobial prescribing for children in hospital

OBJECTIVES

To describe antimicrobial use in hospitalised Australian children and to analyse the appropriateness of this antimicrobial use.

DESIGN

Multicentre single-day hospital-wide point prevalence survey, conducted in conjunction with the Antimicrobial Resistance and Prescribing in European Children study.

SETTING

Eight children's hospitals across five Australian states, surveyed during late spring and early summer 2012.

PATIENTS

Children and adolescents who were inpatients at 8 am on the day of the survey.

MAIN OUTCOME MEASURES

Quantity and quality of antimicrobial prescribing.

RESULTS

Of 1373 patients, 631 (46%) were prescribed at least one antimicrobial agent, 198 (31%) of whom were < 1 year old. The highest antimicrobial prescribing rates were in haematology and oncology wards (76% [95/125]) and paediatric intensive care units (55% [44/80]). Of 1174 antimicrobial prescriptions, 550 (47%) were for community-acquired infections, 175 (15%) were for hospital-acquired infections and 437 (37%) were for prophylaxis. Empirical treatment accounted for 72% of antimicrobial prescriptions for community-acquired infections and 58% for hospital-acquired infections (395 and 102 prescriptions, respectively). A total of 915 prescriptions (78%) were for antibacterials; antifungals and antivirals were predominantly used for prophylaxis. The most commonly prescribed antibacterials were narrow-spectrum penicillins (18% [164 prescriptions]), β-lactam-β-lactamase inhibitor combinations (15% [136]) and aminoglycosides (14% [128]). Overall, 957 prescriptions (82%) were deemed appropriate, but this varied between hospitals (range, 66% [74/112]) to 95% [165/174]) and specialties (range, 65% [122/187] to 94% [204/217]). Among surgical patients, 65 of 187 antimicrobial prescriptions (35%) were deemed inappropriate, and a common reason for this was excessive prophylaxis duration.

CONCLUSION

A point prevalence survey is a useful cross-sectional method for quantifying antimicrobial use in paediatric populations. The value is significantly augmented by adding assessment of prescribing quality.

Anti-infective use in children and pregnancy: current deficiencies and future challenges

There are a number of challenges to using anti-infective agents in children and pregnant women. There is limited understanding of the altered pharmacokinetics of anti-infectives in these populations and as a result, optimized dosing regimens are yet to be established. The potential adverse effects of the drug on pregnancy outcome and the developing foetus is a major consideration, and the long term implications of drug side effects must be taken into account when drug exposure occurs early in life. These factors hinder research and licensing of new anti-infective drugs in these populations. We describe the current deficiencies and future challenges of anti-infective use in children and pregnant women, providing specific examples.

Ureaplasma--Are you sitting comfortably?

The role of Ureaplasma spp. in human disease has been controversial, as these bacteria are commonly isolated as part of the normal genital tract flora. Ureaplasma has been shown to have a causal role in urogenital infections and is associated with significant foetal and neonatal morbidity and mortality when infection occurs during the perinatal period. Although rare, invasive Ureaplasma infection (meningitis, renal abscess, mediastinitis and arthritis) has also been reported in both adults and children. This review outlines the unique microbiological features and various clinical presentations of Ureaplasma infection. It also discusses the treatment options, which in the neonatal period can be particularly challenging.

To x-ray or not to x-ray? Screening asymptomatic children for pulmonary TB: a retrospective audit

OBJECTIVE

Recent studies found that a chest x-ray (CXR) has limited value in the assessment of asymptomatic adults with tuberculosis (TB) infection. We aimed to determine in asymptomatic children with a positive tuberculin skin test and/or interferon-γ release assay (TST/IGRA) whether a CXR identifies findings suggestive of pulmonary TB.

DESIGN, SETTING AND PATIENTS

All children with TB infection (defined as TST ≥10 mm and/or positive IGRA) presenting to The Royal Children's Hospital Melbourne during a 54-month period were included. All CXRs were reviewed by a senior radiologist blinded to the clinical details. The medical records of those with radiological abnormalities suggestive of TB were examined to identify those who were asymptomatic when the CXR was done. Demographical data were also collected.

RESULTS

CXRs were available for 268 of 330 TB-infected children, of whom 60 had CXR findings suggestive of TB. Of the 57 for whom clinical details were available, 26 were asymptomatic. Of these asymptomatic children with radiological abnormalities suggestive of TB, 6 had CXR findings suggestive of active TB, 14 had CXR findings suggestive of prior TB and 6 had isolated non-calcified hilar lymphadenopathy. The six with findings suggestive of active TB represented 2.6% (95% CI 0.9 to 5.5%) of asymptomatic TST/IGRA-positive children with evaluable CXRs. One child with isolated hilar lymphadenopathy had microbiologically-confirmed TB.

CONCLUSIONS

In contrast to the results from studies in adults, a CXR identified a small but noteworthy number of children with findings suggestive of pulmonary TB in the absence of clinical symptoms.

Bacteraemia in Malawian neonates and young infants 2002-2007: a retrospective audit

OBJECTIVES

To assess the causes of bacteraemia in young infants and susceptibility to first-line antibiotics (benzylpenicillin plus gentamicin) at the Queen Elizabeth Central Hospital (QECH), Malawi during 2002-2007.

DESIGN

Retrospective analysis of demographic and microbiological data using laboratory records.

SETTING

QECH is Malawi's largest hospital with 7000 neonates admitted annually, 9% for septicaemia.

PATIENTS

All infants aged 60 days or less admitted to QECH that had a blood culture taken over the 6-year period.

MAIN OUTCOME MEASURES

6754 blood cultures were taken. 3323 organisms were isolated: one-third were pathogens, two-thirds contaminants. Gram-positive organisms (53%) were more common than gram-negatives (47%). Four organisms made up half of all pathogens: Staphylococcus aureus (15.3%), group B streptococci (13.5%), non-typhoidal salmonellae (12.6%) and Escherichia coli (10.5%). Apart from non-typhoidal salmonellae and Streptococcus pneumoniae, most organisms were more common in the first week of life than later. Overall, 28% of isolates during 2002-2007 were resistant to first-line antibiotic, higher than observed during 1996-2001 (22%). Penicillin susceptibility fluctuated while gram-negative resistance to gentamicin increased from 17% to 27% over the study period.

CONCLUSIONS

In the QECH, pathogens causing young infant sepsis are an unusual mix of organisms seen in both developed and developing countries. Resistance to first-line antibiotics is higher than observed in most studies. Ongoing monitoring is needed and clinical outcome data would aid interpretation of findings. A high proportion of blood cultures were contaminated with skin flora-improved training and supervision of phlebotomists are needed to improve the utility of taking blood cultures.