(HealthDay News) – Klebsiella pneumoniae (K. pneumoniae) isolates from U.S. inpatients are becoming increasingly resistant to antimicrobial agents, according to a study published in the January issue of Emerging Infectious Diseases.

Guillermo V. Sanchez, MD, of the George Washington University in Washington, DC, and colleagues used data from The Surveillance Network to examine trends in antimicrobial-resistant K. pneumoniae among U.S. inpatients from 1998–2010.

Data on antimicrobial susceptibility were available for 3,132,354 specimens collected from blood, sputum, urine, and wounds. The researchers found that imipenem resistance was first noted in 2004, and increased gradually to 4.3% by 2010. During the study period, changes in K. pneumoniae antimicrobial resistance varied, ranging from large increases for aztreonam (7.7 to 22.2%), ceftazidime (5.5 to 17.2%), and ciprofloxacin (5.5 to 16.8%), and smaller increases for tetracycline (14.2 to 16.7%) and amikacin (0.7 to 4.5%). In 2010, for all antimicrobial agents except tetracycline, higher levels of drug resistance were found in isolates from the lower respiratory tract versus urine. Isolates of K. pneumonia resistant to imipenem exhibited the least resistance to tetracycline (19.9%) and amikacin (36.8%), and a high prevalence of cross resistance was found for ciprofloxacin (96.4%).

“Our study shows that K. pneumoniae antimicrobial drug resistance increased for every antimicrobial class studied except tetracyclines,” the authors write. “This emerging problem presents a major threat to public health and warrants due diligence in future surveillance efforts.”

Full Text