In vitro activity of tigecycline: MICs, MBCs, time-kill curves and post-antibiotic effect.
The minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), time-kill curves, and postantibiotic effect (PAE) of tigecycline, the first in the glycylcycline class of antibiotics, were evaluated. MICs were determined against 749 clinical isolates. Time-kill curves were performed against two isolates each of Enterococcus faecalis, MSSA, and MRSA. The presence of PAE, against the same isolates, was investigated. MIC(90)s (microg/mL) were the following: Escherichia coli 0.25; Klebsiella spp 0.5; Enterobacter spp 1; Acinetobacter spp. 2; Staphylococcus aureus (MSSA+MRSA) 0.25; CNS (MS+MR) 0.25; vancomycin-susceptible Enterococcus faecalis 0.12. Tigecycline exerted bacteriostatic activity against all the tested isolates, MBC(90)values being 32xMIC. Time-kill experiments showed a marked reduction in bacterial growth. A PAE at 1- to 20-fold the MIC was observed against the two enterococcal isolates (1.5-3.2h, range) and the four staphylococci (1.6-3h, range). Our findings confirm the excellent antimicrobial activity of tigecycline, adding informations on its bacteriostatic activity vs enterococci and staphylococci, whether methicillin-resistant or -susceptible, and its PAE.
Noviello
S
S
Department of Infectious Disease, 2nd University, Naples, Italy.
Ianniello
F
F
Leone
S
S
Fiore
M
M
Esposito
S
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D013293:Enterococcus faecalis / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D000078304:Tigecycline
D000900:Anti-Bacterial Agents; D000078304:Tigecycline; D008911:Minocycline