Clinical impact of methicillin resistance on outcome of patients with Staphylococcus aureus infection: a stratified analysis according to underlying diseases and sites of infection in a large prospective cohort.
OBJECTIVE
This study was conducted to identify the predictors of mortality and to evaluate the impact of methicillin resistance on outcome in patients with Staphylococcus aureus infection according to underlying conditions and type of infection.


METHODS
An observational cohort study including 4949 patients with S. aureus infection was conducted. We compared data from patients with MRSA infection with those with MSSA infection.


RESULTS
The 30-day mortality rate of MRSA group was significantly higher than that of MSSA group (15.6% vs. 6.2%, P < 0.001). However, MRSA infection was not found to be independent risk factor for mortality after adjusting for other variables (OR = 1.03, 95% CI = 0.80-1.32). When we analyzed patients with S. aureus bacteremia (n = 709), MRSA infection was found to be significantly associated with mortality in multivariate analysis (Adjusted OR = 1.69, 95% CI = 1.15-2.49). When the 30-day mortality rates were compared according to underlying diseases, the 30-day mortality rate of MRSA group was significantly higher than that of MSSA group in patients with malignancy or renal diseases. MRSA infection was also found to be one of the independent risk factors for mortality in patients with malignancy (adjusted OR = 1.69, 95% CI = 1.06-2.70) and in those with renal disease (adjusted OR = 1.70, 95% CI = 1.0-2.89), after adjustment for host variables.


CONCLUSIONS
Methicillin resistance adversely affected the outcome of patients with S. aureus infection, in patients with cancer or renal disease and in those with S. aureus bacteremia, although MRSA infection was not found to be significantly associated with higher mortality in overall patient population.
Kang
Cheol-In
CI
Division of Infectious Diseases, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Republic of Korea.
Song
Jae-Hoon
JH
Chung
Doo Ryeon
DR
Peck
Kyong Ran
KR
Ko
Kwan Soo
KS
Yeom
Joon-Sup
JS
Kim
Shin-Woo
SW
Chang
Hyun-Ha
HH
Kim
Yeon-Sook
YS
Jung
Sook-In
SI
Son
Jun Seong
JS
Hsueh
Po-Ren
PR
So
Thomas Man-kit
TM
Lalitha
M K
MK
Yang
Yonghong
Y
Huang
Shao-Guang
SG
Wang
Hui
H
Lu
Quan
Q
Carlos
Celia C
CC
Perera
Jennifer A
JA
Chiu
Cheng-Hsun
CH
Liu
Jien-Wei
JW
Chongthaleong
Anan
A
Thamlikitkul
Visanu
V
Van Pham
Hung
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007674:Kidney Diseases / Q000150:complications; D008297:Male; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D011446:Prospective Studies; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology* / Q000401:mortality; D016896:Treatment Outcome; D055815:Young Adult
D000900:Anti-Bacterial Agents