In vitro activity of linezolid against clinical isolates of Fusobacterium spp.
OBJECTIVE
Although most susceptibility studies for linezolid have investigated aerobic bacteria, only a few have investigated anaerobe isolates. The aim of the present study was to determine the antibacterial activity of linezolid against a larger sample of clinical isolates of Fusobacterium spp. and to report on the detailed susceptibility, stratified by species.


METHODS
The in vitro susceptibility of 80 clinical isolates of Fusobacterium (Fusobacterium necrophorum, n = 34; Fusobacterium nucleatum, n = 20; Fusobacterium varium, n = 18; Fusobacterium mortiferum; n = 8) was tested and compared with the activity of the older compounds amoxicillin and amoxicillin/clavulanic acid.


RESULTS
The MIC of linezolid ranged from 0.016 to 1.0 mg/L, with the MIC(90) being 0.5 mg/L. The highest MIC obtained for linezolid (1.0 mg/L) was measured for an F. varium isolate. The MIC(90) for both, amoxicillin (range: 0.016-0.75 mg/L) and amoxicillin/clavulanic acid (range: 0.047-0.75 mg/L), was 0.5 mg/L. Overall, no resistant strains were found in the study.


CONCLUSIONS
Compared with amoxicillin and amoxicillin/clavulanic acid, linezolid was less active against F. necrophorum (MIC(90) 0.25 mg/L) and F. nucleatum (MIC(90) 0.25 mg/L), equally active against F. varium (MIC(90) 0.75 mg/L) and slightly more active against F. mortiferum (MIC(90) 0.19 mg/L).
Daeschlein
G
G
Institute for Medical Microbiology, Martin-Luther-University Halle-Wittenberg Halle/Saale, Germany.
Hoehne
C
C
Assadian
O
O
Daxboeck
F
F
Meinl
C
C
Kramer
A
A
Kekulé
A S
AS
D000081:Acetamides; D000693:Anaerobiosis; D000890:Anti-Infective Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005673:Fusobacterium / Q000145:classification* / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D006801:Humans; D000069349:Linezolid; D008826:Microbial Sensitivity Tests; D023303:Oxazolidinones; D013045:Species Specificity
D000081:Acetamides; D000890:Anti-Infective Agents; D023303:Oxazolidinones; D000069349:Linezolid