5, 7, 10 or 14 days: appropriate duration of treatment for bacteraemia or an example of 'antimicrobial bingo'?

Concern about serious bacterial infection is a common reason for children to be admitted to hospital, many of whom are given parenteral antibiotics. Once children are converted to oral antibiotics, they are usually discharged home, so the length of parenteral antibiotic treatment is a major determinant of length of stay and total cost of care (unless children can be discharged home on outpatient parenteral antibiotic therapy). The excellent bioavailability of some oral antibiotics (quinolones, clindamycin) means these drugs can rapidly achieve adequate blood levels, making a switch to oral antibiotics more appealing. The duration and route of antimicrobial treatment required for many childhood infections is often based on expert opinion and rarely on evidence. This is particularly true for the duration of parenteral antibiotics for children with Gram-negative blood stream infections. The Infectious Diseases Society of America guidelines for the treatment of catheter-related bloodstream infections acknowledge the lack of evidence in this area, but suggest 7–14 days of intravenous antibiotics should be given for central venous catheter infections due to Gram-negative bacilli. This expert opinion has been taken by some to suggest that up to 14 days of intravenous antibiotics should be given for all blood stream infections due to Gram-negative bacilli in children, such as Escherichia coli. However, no guidance exists for duration of parenteral antibiotic treatment for children who are bacteraemic with a urinary tract infection (UTI). UTIs are the commonest bacterial infection in young infants. Infection can spread from the urinary tract into blood and the meninges. Between 3% and 17% of young infants with UTI also have bacteraemia, with younger infants being more likely to be bacteraemic. Infants with bacteraemic UTIs tend to be given longer courses of parenteral antibiotics than nonbacteraemic children with UTI (6 vs 2 days). Around 1.2% of neonates with UTI have coexisting bacterial meningitis. Clinicians should have a low threshold to perform a lumbar puncture in neonates with UTI. Beyond the neonatal period, the risk of meningitis is small and a more selective approach is warranted. Guidelines for managing UTI in children highlight the evidence that oral antibiotic treatment is as effective as parenteral, although data on oral therapy are limited in very young infants. Some guidelines suggest that parenteral treatment may be required in children with UTI who are ‘toxic’ or who have a ‘complicated’ UTI (high creatinine, fever or abdominal mass), until the child is improving. However, no national or international guidelines give any advice about duration or route of antibiotics for children with bacteraemic UTIs. The linked study by Schroeder et al shows marked variation in the duration of parenteral antibiotics given by paediatricians to treat infants with bacteraemic UTIs in 11 US centres. The duration of parenteral antibiotics mostly seemed to depend on local practice, with each institution having a different mean duration (5, 7, 10 or 12 days). Duration of parenteral antibiotics did not seem to be influenced much by clinical features (fever, comorbidities, ill appearance), but was influenced by age, if the child had a second positive blood culture and if the organism causing the UTI was not E. coli. Duration of parenteral treatment thus seemed most influenced by local practice, rather than other features. Despite this variation, duration of parenteral antibiotic treatment did not seem to influence outcome or relapse of infection. Recurrence of UTI was influenced by anatomical factors such as veiscoureteric reflux, not duration of parenteral antibiotics. Only one child had a relapse of bacteraemia, despite receiving 11 days of parenteral treatment. Why is there such variation in practice? No guidelines are available to guide clinicians in this infrequent situation. The institutions in the study saw 1–5 infants with bacteraemic UTI per year, meaning few clinicians saw this presentation on a regular basis. No studies compare 7 vs 10 vs 14 days of antibiotic treatment for children with UTI, and studies comparing antibiotic duration in bacteraemic children with UTIs will be difficult to do because of the infrequent occurrence of the condition.