Extended spectrum β-lactamase–producing Klebsiella pneumoniae chronic ambulatory peritoneal dialysis peritonitis treated successfully with polymyxin B

Peritonitis is not an infrequent complication of inpatients with chronic ambulatory peritoneal dialysis (CAPD). CAPD peritonitis may be related to the catheter or secondary to perforation of an intra-abdominal viscus. The most common organisms usually associated with CAPD peritonitis are Staphylococcus aureus and Staphylococcus epidermidis (coagulase-negative staphylococci). Rarely, aerobic gram-negative bacilli have been the causative agents of CAPD peritonitis. The treatment of CAPD peritonitis usually requires removal of the peritoneal catheter and treatment with parenteral antibiotics active against the causative pathogen. We report a case of CAPD-associated peritonitis caused by an extended spectrum β-lactamase–producing strain of Klebsiella pneumoniae. The case presented had this strain of multidrug-resistant K. pneumoniae present in blood cultures and the peritoneal fluid. Extended spectrum β-lactamase–producing bacteria, for example, K. pneumoniae, are multidrug-resistant and sensitive to few antibiotics. This isolate was intermediately sensitive to amikacin and meropenem, but the patient did not clinically improve on these 2 antibiotics. Polymyxin B therapy was initiated after lack of clinical improvement after dialysis catheter removal and 1 week of meropenem and amikacin therapy. The patient responded rapidly to therapy with polymyxin B. Polymyxin B has a unique mechanism of action on bacterial cells and is highly active against all multidrug-resistant gram-negative organisms except Proteus species and Serratia marcescens. No toxicity was observed during therapy. Polymyxin B is being used increasingly as a therapeutic alternative to multidrug-resistant gram-negative organisms.