Mupirocin for controlling methicillin-resistant Staphylococcus aureus: lessons from a decade of use at a university hospital.
BACKGROUND
From 1990 to 1995 at Hospital Universitário Clementino Fraga Filho, patients colonized or infected with methicillin-resistant Staphylococcus aureus (MRSA) were treated with mupirocin to eliminate MRSA carriage. In 1995, 65% of MRSA patients at this hospital had mupirocin-resistant isolates. Starting in 1996, mupirocin use was restricted to patients colonized, but not infected, with MRSA.


OBJECTIVE
To describe the use of mupirocin for controlling MRSA over a decade and to analyze the molecular epidemiology of mupirocin-resistant MRSA infections at this hospital.


METHODS
A 490-bed, tertiary-care university hospital.


METHODS
The incidence densities of patients with MRSA and acquisition of mupirocin by the hospital were calculated for the period 1992-2001. S. aureus isolates from 1999-2000 were analyzed by pulsed-field gel electrophoresis. Mupirocin-resistant MRSA isolates from 1994-1995 and 1999-2000 were analyzed for ileS-2 gene background polymorphisms.


RESULTS
The incidence density of MRSA patients increased slightly over time, whereas the purchase of mupirocin decreased dramatically. Mupirocin-resistant MRSA infections decreased from 65% in 1994-1995 to 15% in 1999-2000. The MRSA Brazilian clone, detected in 1992, was still highly prevalent. The same ileS-2 encoding plasmid found in 1994-1995 persisted in three identical MRSA isolates from 1999-2000 belonging to the Brazilian clone.


CONCLUSIONS
After mupirocin use decreased, the ileS-2 encoding plasmid persisted in only a few Brazilian clone isolates. Our data on mupirocin-resistant MRSA incidence and mupirocin use strongly suggested that restricted use was related to decreased rates of mupirocin resistance at our hospital.
Vivoni
Adriana M
AM
Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Santos
Kátia R N
KR
de-Oliveira
Márcia P
MP
Giambiagi-deMarval
Marcia
M
Ferreira
Adriana L P
AL
Riley
Lee W
LW
Moreira
Beatriz M
BM
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015373:Bacterial Typing Techniques / Q000379:methods; D001938:Brazil / Q000453:epidemiology; D003428:Cross Infection / Q000188:drug therapy* / Q000382:microbiology / Q000517:prevention & control; D004269:DNA, Bacterial / Q000235:genetics; D006785:Hospitals, University / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D017053:Infection Control / Q000379:methods / Q000706:statistics & numerical data*; D016106:Methicillin Resistance / Q000187:drug effects*; D016712:Mupirocin / Q000627:therapeutic use*; D011110:Polymorphism, Genetic; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D016712:Mupirocin