Differences in clinical outcomes in patients with vancomycin-resistant enterococci according to linezolid susceptibility.
OBJECTIVE
To evaluate the differences in clinical outcomes in patients with linezolid-intermediate or -resistant vancomycin-resistant enterococci (LIRVRE) isolates, as defined by the presence of the G2576T mutation, compared with patients who had linezolid-susceptible VRE (LSVRE) isolates in order to further discern the clinical relevance of linezolid resistance associated with this mutation.


METHODS
Retrospective cohort study.


METHODS
Large tertiary care academic medical center.


METHODS
Eighteen adults (mean age 55.4 yrs) with LIRVRE (case patients) who were frequency matched to 54 adults (mean age 58.1 yrs) with LSVRE (control patients) in a 1:3 ratio based on site of culture and VRE species.


RESULTS
Linezolid resistance was determined by phenotype and genotype (G2576T mutation by polymerase chain reaction). Patients with LIRVRE received more linezolid before isolation of the organism than did those with LSVRE (mean 8.6 vs 0.2 days, p<0.001). No difference in mortality was found; however, compared with controls, patients with LIRVRE were more likely to be transferred to the intensive care unit (56% vs 28%, p=0.032), had more surgical procedures for VRE (39% vs 15%, p=0.029), and had more echocardiograms performed (44% vs 19%, p=0.028) as a result of their VRE. Multivariate analysis revealed that surviving case patients had an increased duration of culture positivity of approximately 1.5 days (p=0.049) and a near statistically significant increase of postculture length of stay of approximately 2 days (p=0.053).


CONCLUSIONS
The clinical relevance of the G2576T mutation among enterococci remains unclear; however, the increased morbidity and resource utilization among patients with LIRVRE is a finding of concern. Careful monitoring of genotypically confirmed LIRVRE emergence and ongoing epidemiologic studies will be critical to better characterize the clinical relevance of linezolid resistance.
Department of Pharmacy, Northwestern Memorial Hospital, Chicago, Illinois, USA. mscheetz@nmh.org
Marc H
MH
Scheetz
Stephanie A
SA
Knechtel
Michael J
MJ
Postelnick
Michael
M
Malczynski
Chao
C
Qi
D000081:Acetamides / Q000494:pharmacology / Q000627:therapeutic use*; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016983:Enterococcus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D006801:Humans; D000069349:Linezolid; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000187:drug effects; D023303:Oxazolidinones / Q000494:pharmacology / Q000627:therapeutic use*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D020713:Vancomycin Resistance / Q000235:genetics*
D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D000069349:Linezolid