Cluster of cases of Mycobacterium chelonae bacteraemia

Mycobacterium chelonae was isolated from the blood of four immunosuppressed patients over a period of 10 weeks. Three patients had intravascular cathe ters in situ and the other had a biliary stent. All presented with recurren t fever despite treatment with broad-spectrum antibiotics. Blood cultures u sing standard bacteriological medium yielded a gram-positive bacillus from each patient. Ziehl-Neelsen staining of these cultures demonstrated a branc hing acid-fast bacillus that was subsequently identified as Mycobacterium c helonae in each case. The isolates were sensitive to clarithromycin and, al though success of treatment with clarithromycin monotherapy has been variab le, this antibiotic combined with removal of the intravascular catheters wa s used to treat those three patients. The treatment was successful with no recurrence of symptoms after 12 months of follow-up. The patient with the b iliary stent died soon after Mycobacterium chelonae was isolated. Pyrolysis mass spectrometry analysis indicated the isolates were of two distinct str ains. Radiological insertion of the Hickman lines and biliary stent was imp licated epidemiologically as the source of infection.