Strains of Klebsiella pneumoniae that produce one of three possible 
carbapenemases--KPC--have recently been identified with increasing frequency 
among isolates recovered from patients residing along the East Coast of the 
United States, particularly within the New York City metropolitan region. These 
strains have exhibited resistance to multiple antibiotic classes, including 
carbapenem agents. We report a case of nosocomial pneumonia and empyema caused 
by a KPC-producing isolate of K. pneumoniae at a large midwestern U.S. tertiary 
care facility in which the patient was treated with tigecycline. Although the 
pneumonia was treated successfully, the empyema recurred in association with a 
treatment-emergent tigecycline minimum inhibitory concentration (MIC) increase 
from 0.75 to 2 microg/ml. Clinicians should be aware of the potential occurrence 
of this treatment-emergent MIC increase, especially in the setting of sustained 
tigecycline therapy. In addition, the emergence of carbapenem-resistant 
Enterobacteriaceae reinforces the importance of antibiotic stewardship and 
strict infection control practices.