In vitro susceptibility of Gram-positive pathogens to linezolid and teicoplanin and effect on outcome in critically ill patients.
OBJECTIVE
To determine the prevalence of teicoplanin and linezolid resistance amongst Gram-positive pathogens isolated in the intensive care unit (ICU) and the impact of any resistance on clinical outcome.


METHODS
Gram-positive isolates were collected from two critical care units over 1 year. All patients were screened weekly for methicillin-resistant Staphylococcus aureus (MRSA). Susceptibility to teicoplanin and linezolid was tested by Etest. The length of hospital and critical care unit stay and the use of antibiotics in each patient were recorded.


RESULTS
Reduced susceptibility to teicoplanin (MIC>or=16 mg/L) was found in 21 [3.3% (95% CI 2.0-5.0%) 6 patients] of 643 strains of MRSA versus none of 374 methicillin-susceptible S. aureus (MSSA) [<0.3% (95% CI 0-0.9%)]. Of 49 enterococci 3 were teicoplanin-resistant. All Gram-positive isolates were susceptible to linezolid. The length of treatment with teicoplanin and outcome of patients infected with these strains were similar to that of susceptible strains. MRSA was a more common cause of infection than MSSA but a less frequent colonizer.


CONCLUSIONS
Resistance to teicoplanin remains at a comparatively low level and there was no clear relationship between susceptibility and outcome in this critically ill population. There was no resistance in Gram-positives to linezolid but this should be kept as a reserve antibiotic to maintain its activity.
Wilson
A Peter R
AP
Department of Clinical Microbiology, University College London Hospitals, 46 Cleveland Street, London W1T 4JF, UK. peter.wilson@uclh.nhs.uk
Cepeda
Jorge A
JA
Hayman
Samantha
S
Whitehouse
Tony
T
Singer
Mervyn
M
Bellingan
Geoffrey
G
D000081:Acetamides / Q000494:pharmacology* / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D016638:Critical Illness; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D007297:Inpatients; D007362:Intensive Care Units; D007902:Length of Stay; D000069349:Linezolid; D008826:Microbial Sensitivity Tests; D023303:Oxazolidinones / Q000494:pharmacology* / Q000627:therapeutic use; D017334:Teicoplanin / Q000494:pharmacology* / Q000627:therapeutic use; D016896:Treatment Outcome
D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D017334:Teicoplanin; D000069349:Linezolid