Antimicrobial activity of tigecycline tested against bacterial pathogens from intensive care units

Abstract number: 1134_02_18

Sader H., Fritsche T., Jones R.

Objectives:

To evaluate the antimicrobial activity of tigecycline (TIG) and selected antimicrobials against bacterial pathogens isolated from patients hospitalized in intensive care units (ICUs) worldwide.

Methods:

A total of 7129 were consecutively collected in >70 medical centres located in North America (3164), South America (1465), Europe (2428) and the Asia–Australia region (72). The isolates were collected from (no. of isolates/%): bloodstream (5349/75%), respiratory tract (746/10%), skin/soft tissue (323/5%), and urinary tract (182/3%) infections in the 2000–2004 period, and susceptibility tested by NCCLS broth microdilution methods.

Results:

The antimicrobial activity of TIG and the frequency of occurrence of bacterial pathogens are summarized in the Table: All Gram-positive pathogens (4817) were inhibited at <1 mg/L of TIG. Resistance (R) to oxacillin was detected in 43% of SA and 84% of CoNS, and R to vancomycin was detected in 19% of enterococci. TIG was very active against Enterobacteriaceae (ENT; 1468) with a MIC90 <1 mg/L, except for Serratia spp. 10% of E. coli and 30% of Klebsiella spp. showed an ESBL phenotype while 28% of Enterobacter spp. were R to ceftazidime. 14% of ENT showed R to ciprofloxacin. TIG and trimethoprim/sulfamethoxazole were the most active compounds against S. maltophilia (MIC90, 2 and 1 mg/L respectively). TIG was also highly active against ASP (MIC90, 1 mg/L), but PSA showed decreased S to TIG (MIC90, 16 mg/L). Non-S to imipenem (MIC, >8 mg/L) was observed in 16% of ASP and 31% of PSA isolates.

Conclusions:

Isolates from ICU patients showed high rates of antimicrobial R. The most alarming problems detected were vancomycin R among enterococci, ESBL mediated beta-lactam R and fluoroquinolone R among ENT, and carbapenem R among PSA and ASP. TIG exhibited potent in vitro activity against the vast majority of clinically important pathogenic bacteria (except PSA) isolated from ICU patients and may represent an excellent option for the treatment of infections in this clinical environment.