Comparison of in vitro activities of levofloxacin, ciprofloxacin, ceftazidime, cefepime, imipenem, and piperacillin-tazobactam against aerobic bacterial pathogens from patients with nosocomial infections.
OBJECTIVE
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.


METHODS
Antimicrobial susceptibility was evaluated by E test in accordance with the guidelines of the National Committee for Clinical Laboratory Standards.


RESULTS
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.


CONCLUSIONS
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.
Huang
Shie Shian
SS
Division of Infectious Diseases, Chang Gung Memorial Hospital, Keelung, Taiwan.
Lee
Sai Cheong
SC
Lee
Ning
N
See
Lai Chu
LC
Tsai
Ming Han
MH
Shieh
Wen Bin
WB
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001420:Bacteria, Aerobic / Q000187:drug effects* / Q000302:isolation & purification; D001424:Bacterial Infections / Q000382:microbiology*; D003428:Cross Infection / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D008826:Microbial Sensitivity Tests; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D047090:beta-Lactams