Molecular diagnosis of vascular access device-associated infection in children being treated for cancer or leukaemia.

Blood samples were collected for quantitative 16S rDNA analysis from the vascular access device (VAD) of patients presenting with fever at participating centres of the UK Children's Cancer and Leukaemia Group. In total, 260 of 301 episodes of fever were evaluable and were classified as probable, possible, unlikely or unclassifiable VAD-associated infection. The sensitivity of the 16S rDNA assay declined concomitantly with delays from time of presentation to sampling. The sensitivity with >0.125 pg of bacterial DNA/microL of whole blood was 80% for the 20 probable VAD-associated infections diagnosed with samples collected on the day of or day following presentation. The specificity rose with increasing amounts of bacterial DNA, from 93% with >0.125 pg, to 98% with 0.25-0.5 pg, and to 100% with >0.5 pg/microL blood. The positive predictive value (for probable or possible) was 88% (95% CI 70-98%) with 0.25 pg/microL, and 100% (95% CI 83-100%) with >0.5 pg/microL. All 18 (6.8%) episodes with >0.5 pg of bacterial DNA/microL blood were associated with positive blood cultures. Identifications derived from the DNA sequence were consistent with the blood culture identifications for 15 of the 17 episodes with a DNA sequence identification. The VAD was removed because of suspected infection in six (2.8%) of 216 episodes with <0.125 pg of bacterial DNA/microL, in one (5%) of 20 episodes with 0.125-0.25 pg/microL, in one (16.7%) of six episodes with 0.25-0.5 pg/microL, and in nine (50%) of 18 episodes with >0.5 pg/microL. A bacterial DNA concentration of >0.5 pg/microL in blood drawn through a central venous catheter at the time of fever presentation had a high positive predictive value for VAD-associated infection and predicted an increased risk of VAD removal because of suspected infection.

Cardiac troponin T following anthracycline chemotherapy in children and adolescents.

Cardiac troponin T (CTT) is elevated acutely in animal models of anthracycline cardiotoxicity. We assessed CTT release in children receiving anthracylines using a third generation assay. We measured CTT in 30 children receiving anthracycline chemotherapy. A total of 3 samples were taken from each child: 1) prior to, 2) immediately after and 3) between 24-48 hours after the infusion. The dose range given during the measurements of cardiac troponin T was 15-60 (median 25) mg/m(2) and the previous exposure ranged from 0-300 (median 150) mg/m(2). Not one child had a detectable CTT level at any time. This study shows a lack of acute elevation CTT following anthracycline administration. In this respect it is unlikely that early estimation of CTT using this modern assay will be useful for screening for anthracycline cadiomyopathy. Further studies using a third generation assay, are, however, indicated to determine whether delayed elevation of CTT occurs.

Pet ownership in immunocompromised children--a review of the literature and survey of existing guidelines.

Pet ownership has been associated with both emotional and physical health benefits. However, owning pets may also pose health risks to immunocompromised patients through zoonotic transmission of disease. Our initial impression was that there is a lack of any evidence base in information given by health care professionals regarding these risks. We therefore aimed to produce evidence-based guidelines addressing this issue. A Pubmed search was undertaken and a variety of literature on zoonoses reviewed. Existing guidelines were evaluated and a survey of all Paediatric Oncology Centres in the UK performed. There is a paucity of level 1 and 2 data addressing this issue and clearly more studies, particularly Randomised Controlled Trials (RCTs), are required. Nevertheless, general themes emerged and certain specific guidance was produced based on that produced by the Centres for Disease Control and Prevention in the US. Animal-associated pathogens of concern include Toxoplasma gondii, Cryptosporidium spp., Salmonella spp., Campylobacter spp., Giardia lamblia, Rhodococcus equi, Bartonella spp., Bordetella bronchiseptica, Chlamydia psittaci and dermatophytes. Despite this, the literature would suggest that with the exception of Bartonella henselae and dermatophytes only a relatively small number of infections in people are likely to be associated with pet contact. The majority of pet species do not appear to pose a major risk to immunocompromised children. Some animals, particularly reptiles, should be avoided because of the high risk of salmonellosis. Guidelines include general advice on good hygiene practices, veterinary care, pet foods, purchasing of new pets and age restrictions. Health care professionals should actively enquire about household pets and provide accurate information and practical advice on how to minimise the risk of infection. However, the overall benefits of the human-animal bond must be considered and with proper handling and husbandry immunocompromised patients should be able to continue to enjoy the significant benefits of pet ownership.

A prospective study of septicaemia on a paediatric oncology unit: a three-year experience at The Royal Liverpool Children's Hospital, Alder Hey, UK.

Septicaemia in neutropaenic patients is predominantly due to gut translocation [endogenous septicaemia] and contamination of the central venous catheter by microorganisms not carried by the patient [exogenous septicaemia]. To control both types of infection, a protocol was implemented based on pre 1990's parenteral and enteral antimicrobials together with strict hygiene. Surveillance cultures of throat/rectum were taken to distinguish exogenous from endogenous septicaemia and enteral non-absorbable antibiotics are administered as part of selective decontamination of the digestive tract (SDD). This protocol was evaluated in a 14-bedded paediatric oncology unit over a period of 3 years. 313 Septicaemia episodes were recorded in 131 children. 28.4% of the septicaemias were caused by microorganisms associated with the unit, equivalent to 0.82 episodes per 100 patient days. Low-level pathogens such as coagulase-negative staphylococci caused more than 70% of infections. Amongst the potential pathogens, Pseudomonas species (7.8%) and Staphylococcus aureus (5.5%) were predominant. Antibiotic resistance was rare with no superinfections or outbreaks. Four patients (3%) died, two due to Candida species and two due to Pseudomonas aeruginosa. We believe that the addition of enteral non-absorbable antibiotics to systemic antibiotics maintained a low level of resistance and mortality but a randomised controlled trial is indicated to confirm these observations.