Comparison of in vitro activities of levofloxacin, ciprofloxacin, ceftazidime, cefepime, imipenem, and piperacillin-tazobactam against aerobic bacterial pathogens from patients with nosocomial infections
Shie-Shian Huang, Sai-Cheong Lee, Ning Lee, Lai-Chu See, Ming-Han Tsai, Wen-Bin Shieh
Division of Infectious Diseases, Chang Gung Memorial Hospital, Keelung; Division of Infectious Diseases, Chang Gung Institute of Technology, Kwei-Shan Tao-Yuan; Department of Pathology, Chang Gung Memorial Hospital, Keelung; Department of Public Health, Chang Gung University, Kwei-Shan Tao-Yuan; and Departments of Pediatrics and Internal Medicine, Chang Gung Memorial Hospital, Keelung, Taiwan
Received: March 6, 2006 Revised: April 30, 2006 Accepted: July 13, 2006
Background and purpose:
There is a rapid worldwide emergence of multidrug-resistant pathogens, especially in nosocomial isolates. This study compared the in vitro activities of levofloxacin, ciprofloxacin, ceftazidime, cefepime, imipenem, and piperacillin-tazobactam against 208 aerobic bacterial pathogens that caused 197 nosocomial infections in 184 patients.
Antimicrobial susceptibility was evaluated by E test in accordance with the guidelines of the National Committee for Clinical Laboratory Standards.
Most (140/208, 67%) of the isolates were facultative Gram-negative bacilli. Levofloxacin and ciprofloxacin were the most effective (22/22, 100%) against oxacillin-sensitive Staphylococcus aureus. None of the antibiotics tested were found to be effective (0/25) against oxacillin-resistant S. aureus. Of the 11 isolates of Acinetobacter baumannii that were not pandrug-resistant (PDR), only 9 isolates (9/11, 81%) were sensitive to imipenem and 5 isolates (5/11, 45%) were sensitive to levofloxacin, ciprofloxacin, and ceftazidime. Another 22 isolates of A. baumannii that were PDR were completely resistant to all 6 antibiotics. The majority of isolates of Pseudomonas aeruginosa were sensitive to these 6 antimicrobial agents with 10/11 (91%) sensitive to levofloxacin and ciprofloxacin, 9/11 (83%) sensitive to ceftazidime, cefepime and piperacillin-tazobactam, and 8/11 (75%) sensitive to imipenem.
The majority of the bacterial isolates causing nosocomial infections were found to be sensitive to the 6 antibiotics tested. Bacterial isolates of nosocomial infections that were completely resistant to these 6 antibiotics were PDR A. baumannii, PDR P. aeruginosa, and oxacillin-resistant S. aureus. More potent antimicrobial agents are needed to treat infections caused by PDR A. baumannii and PDR P. aeruginosa.
Anti-bacterial agents; Bacterial infections; Cross infection; Drug resistance, bacterial; Taiwan
J Microbiol Immunol Infect. 2007;40:134-140.