Length of exposure to the hospital environment is more important than antibiotic exposure in healthcare associated infections by methicillin-resistant Staphylococcus aureus: a comparative study.
OBJECTIVE
Both total antimicrobial use and specific antimicrobials have been implicated as risk factors for healthcare-associated methicillin-resistant Staphylococcus aureus (HCA-MRSA) infection. The aims of this study were: (I) to explore predictors of a new HCA-MRSA infection in comparison with a new healthcare-associated methicillin-sensitive Staphylococcus aureus (HCA-MSSA); (II) to thoroughly assess the role of recent antibiotic use qualitatively and quantitatively.


METHODS
The time-period for our study was from October 1997 through September 2001. Through applying strict criteria, we identified two groups of inpatients, one with a new HCA-MRSA infection and one with a new HCA-MSSA infection. We recorded demographic, clinical and antibiotic use-related data up to 30 days before the positive culture date.


RESULTS
We identified 127 and 70 patients for each group, respectively. Two logistic regression models were carried out to assess the role of antimicrobial use (qualitatively and quantitatively). In model I, duration of hospital stay, presence of chronic wounds, aminoglycoside and fluoroquinolone use retained statistical significance. In model II, duration of hospital stay and history of intubation during the last month stood out as the only significant predictors of a subsequent HCA-MRSA infection. No significant differences in outcome were noted.


CONCLUSIONS
The length of exposure to the hospital environment may be the best predictor of a new HCA-MRSA infection. Use of aminoglycosides and fluoroquinolones may also stand independently along with presence of chronic ulcers and surgical procedures. No independent association between quantitative antibiotic use and subsequent HCA-MRSA infection was documented.
Infectious Diseases and HIV Division, Evangelismos General Hospital, Athens, Greece. ioannisbaraboutis@yahoo.gr
Ioannis G
IG
Baraboutis
Eleftheria P
EP
Tsagalou
Ilias
I
Papakonstantinou
Markos N
MN
Marangos
Charalambos
C
Gogos
Athanasios T
AT
Skoutelis
Haralambos
H
Bassaris
Stuart
S
Johnson
D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D003428:Cross Infection / Q000382:microbiology* / Q000635:transmission; D004781:Environmental Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007440:Intubation / Q000009:adverse effects; D007902:Length of Stay; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000635:transmission; D013211:Staphylococcus aureus / Q000187:drug effects; D014947:Wounds and Injuries / Q000382:microbiology
D000900:Anti-Bacterial Agents