Development of daptomycin-susceptible, methicillin-resistant Staphylococcus aureus pneumonia during high-dose daptomycin therapy.

tical RAPD patterns and pulsotypes (Figure 1) were found in the 4 isolates (isolates A, B, C, and D). RAPD patterns and pulsotypes of isolates E, F, and G were different from those of A, B, C, and D. We report a case with repeated bacteremia and septic arthritis due to K. pneumoniae serotype K57 in a patient with multiple underlying medical conditions (diabetic mellitus, liver cirrhosis, and hepatocellular carcinoma). To the best of our knowledge, 19 cases of septic arthritis due to K. pneumoniae have been reported in the English-language literature [1, 6– 9]. Among 13 patients with Klebsiella arthritis reviewed by Schelenz et al [3], 4 had diabetes mellitus, 1 had liver cirrhosis, and 1 had malignancy. Findings from a recent study indicate that diabetes mellitus is strongly correlated with recurrent K. pneumoniae infections [10]. The identical pulsotypes and RAPD patterns of the 4 K. pneumoniae isolates recovered within an 18-month period from our patient indicated that the unidentified and noneliminated primary foci was responsible for repeated bacteremia, which resulted in septic arthritis due to the same strain of K. pneumoniae. A previous study has concluded that patients with pyogenic liver abscess caused by non-K1 K. pneumoniae are considered to be more associated with diabetes mellitus, compared with those with infections caused by serotype K1 [1]. Impaired phagocytosis of capsular serotypes K1 or K2 K. pneumoniae is found in diabetic patients with poor glycemic control [2]. Little is known about patients infected with serotype K57 K. pneumoniae. The impaired phaygocytosis of non-K1 K. pneumoniae strains in patients with poor diabetic control (glycosylated hemoglobin level 19.0%) might partly contribute to the repeated bacteremia that occurred, despite adequate antimicrobial treatment, in our patient.