[Colonization by methicillin-resistant Staphylococcus aureus is a predictive factor for the resistance phenotype of an infectious strain of S. aureus].
OBJECTIVE
To assess the predictive value of a previous colonization with methicillin-resistant Staphylococcus aureus for the resistance pattern of a bacteriological specimen significantly positive to S. aureus.


METHODS
Retrospective study of patients' files.


METHODS
Patients admitted for at least 48 hours in a surgical intensive care unit from April 1, 1996 to December 31, 1997.


METHODS
Collection of patients' characteristics and chronology of positive microbiological specimens with methicillin-susceptible (MSSA) or -resistant (MRSA) S. aureus from medical and laboratory records. During the study period, screening for nasal or perineal colonization with MRSA was systematically performed on admission and weekly thereafter.


RESULTS
The files of 540 patients were reviewed. MSSA and MRSA infections occurred in 7% (39/540) and 4% (20/540) of the patients respectively. By opposition with MSSA infections, MRSA infections occurred more frequently in patients previously colonized with MRSA (13 infections in 63 colonized patients [21%] versus 7 infections in 477 non-colonized patients [2%], odds ratio = 18, confidence interval: 6-51, P < 0.0001). The median delay between colonization and infection was 5 days. The positive and negative predictive values for previous colonization with MRSA to predict infection with MRSA in presence of a bacteriological specimen significantly positive with S. aureus were 81 and 84%, respectively.


CONCLUSIONS
The probabilistic use of a glycopeptide in presence of a bacteriological specimen significantly positive with S. aureus should be limited to patients already colonized with MRSA, in order to decrease the abusive administration of these antibiotics.
Truffault
A
A
Service d'anesthésie-réanimation chirurgicale, centre hospitalo-universitaire de Bicêtre, Le Kremlin-Bicêtre, France.
Mimoz
O
O
Karim
A
A
Edouard
A
A
Nordmann
P
P
Samii
K
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D009104:Multiple Trauma / Q000150:complications / Q000382:microbiology; D009296:Nasal Cavity / Q000382:microbiology; D010297:Paris / Q000453:epidemiology; D010343:Patient Admission / Q000706:statistics & numerical data; D010502:Perineum / Q000382:microbiology; D010641:Phenotype; D011183:Postoperative Complications / Q000382:microbiology; D011237:Predictive Value of Tests; D012008:Recurrence; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D013503:Surgery Department, Hospital / Q000706:statistics & numerical data