A Clinical Study on Staphylococcus Aureus Bacteremia

Hong, Hwa Jeong; Lee, Chung Hwan; Park, Chong Oh; Jung, Il Woo; Lee, Seung Ho; Ko, Kyung Sik; Kim, Koo Yeop; Suh, Hwan Jo

Abstract

OBJECTIVE
Staphylococcus aureus has persisted and is now resurging as an important hospital and community pathogen. Nosocomial infection caused by methicillin-resistant S.aureus(MRSA) is a major problem which may be connected with heavy or prolonged use of antibiotics S.aureus bacteremia caused acute complications, which occasionally resulted in death, and infectious/suppurative complications, which necessitated prolonged antibiotic therapy, sometimes in conjunction with surgery. Therefore, S.aureus bacteremia is a serious medical problem in association with high morbidity and mortality.
METHODS
130 patients with S.aureus bacteremia who were admitted in the Kyung Hee University Hospital from January, 1991 to December, 1994 were analyzed retrospectively. We compared the clinical and laboratory characteristics, and antibiotics resistances between MRSA and MSSA bacteremia and also we evaluated risk factors that contribute to fatal outcome in patients with S.aureus bacteremia.
RESULTS
1) of 130cases, 80 were male and 50 were female. The mean age was 44.5+/-25.1 years. 2) 84(65%) of S.aureus bacteremia were nosocomial and 46(35%) were community-acpuired. The percentage of MRSA stains studied was 55%(71/130) and The percentage of MRSA bacteremia in hospital-acpuired and community-accquired S. aureus bacteremia were 64% (54/84) and 36%(17/46), respectively. Sources of bacteremia were uncertain in 85(65%) with intravascular catheter(20%) and skin wound sites (8%) being the most common sources in remainder(35%) 3) 110(85%) of 130 patients had one or more underlying diseases. Common underlying dieases were cerebrovascular disease(33%), malignancy(17%), Diabetes mellitus(15%), chronic renal failure(8%) and liver cirrhosis(6%). 4) Acute complications occurred in 35 patients and were fatal in 21 5) The risk factors associated with MRSA bacteremia were various severe underlying diseases, vairous invasive procedures, IV catheter-associated infection, hypoalbuminemia, previous use of antibiotics, male sex and old age. 6) The Case fatality rate for patients with S. aureus bacteremia was 18% and those for patients with MRSA and MSSA bactermia were 20% and 12%, respectively. The risk factors that contribute to the increment of mortality rate in patients with S. aureus bacteremia were acute complication, low serum level of total protein, hypoalbuminemia, various invasive procedures and IV catheter-associated infection, 7) In the antibiotic sensitivity test S. aureus was resistant to penicillin in 98.5%, ofloxacin in 73%, cefotaxime in 67%, erythromycin in 58%, aztreonam in 56%, clindamycin in 52%, vancomycin in 0%. 8) In the multiple antibiotic resistance of S. aureus, 43(68%) of MRSA was resistant to more than 10 antibotics, revealing multiply resistant nature of strains, While all but one MSSA was resistant to 1 to 4 antibiotics, one revealing resistance to 8 antibiotics.
CONCLUSION
S. aureus bacteremia is a cause of considerable morbidity and mortality in hospitalized patients who especially, exposed to various risk factors. MRSA revealed higher resistance rate to most antibiotics tested and more marked multiply resistant nature than MSSA. But there was no significant difference in case fatality rate between patients with MRSA and MSSA bacteremia.