A 15-year-old girl developed a persistent bacteraemia with Klebsiella pneumoniae accompanied by systemic symptoms including high fever and rigors after appendectomy. Extensive laboratory and imaging work-up, including tests for an intra-vascular source of infection, did not reveal the origin of the persistent bacteraemia. The Klebsiella pneumoniae isolates were susceptible to gentamicin and colistin and intermediately susceptible to meropenem. The septicaemia persisted despite the intravenous administration of meropenem 1 g and later 2 g every 8 h in combination with intravenous gentamicin and later colistin. The patient was cured only after the continuous intravenous administration of meropenem of 6 g/d.