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A Comparison of Clinical Virulence of Nosocomially Acquired Methicillin-Resistant and Methicillin-Sensitiye Staphylococcus aureus Infections in a University Hospital

Published online by Cambridge University Press:  21 June 2016

Ronald C. Hershow*
Affiliation:
School of Medicine, University of Illinois at Chicago, Chicago, Illinois School of Public Health, University of Illinois at Chicago, Chicago, Illinois
Walid F. Khayr
Affiliation:
School of Medicine, University of Illinois at Chicago, Chicago, Illinois
Nina L. Smith
Affiliation:
School of Medicine, University of Illinois at Chicago, Chicago, Illinois
*
University of Illinois at Chicago, School of Public Health, 2121 W. Taylor St., Chicago, IL 60612

Abstract

Objectives:

To compare the clinical virulence of nosocomially acquired methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S aureus (MSSA) infections in 1989.

Design:

A retrospective comparison of host factors, in-hospital exposures, sites of infections, and outcomes of patients with nosocomial MRSA and MSSA infections.

Setting:

University of Illinois Hospital, Chicago, Illinois.

Participants:

Forty-four adult patients with nosocomial S aureus infections.

Results:

The 22 MRSA-infected and 22 MSSA-infected persons were similar regarding mean age, gender, underlying diseases, and exposure to surgery. Before developing infection, MRSA-infected persons were more likely to have received antibiotics (73% compared with 27%, odds ratio = 7.1, 95% confidence interval [CI95] = 2.0-25.8 p = .003) and to have stayed in the hospital >2 weeks (64% compared with 18%, odds ratio = 7.9, CI95 = 2.0-31.6, p = .002). Bacteremia was the most common presentation in the MRSA and MSSA groups (55% and 59%, respectively). Infectious complications and death were infrequent in both groups.

Conclusions:

MRSA and MSSA strains infect patients with similar demographic features and underlying diseases, but MRSA infections are significantly more common among patients with previous antibiotic therapy and a prolonged preinfection hospital stay. Clinical presentations and outcomes did not differ significantly between the 2 groups. Thus, similar to studies in the early 1980s, our findings do not suggest greater intrinsic virulence of MRSA.

Type
Original Articles
Copyright
Copyright © The Society for Healthcare Epidemiology of America 1992 

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