[Risk factors of nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus].
OBJECTIVE
To include a specific antibiotic in the empiric therapy, it is necessary to predict when a nosocomial pneumonia (NP) is caused by methicillin-resistant Staphylococcus aureus (MRSA). We have developed a model for the prediction of the probability of a NP being caused by MRSA, when the carrier status and the microbiological diagnosis are unknown.


METHODS
A retrospective case-control study (1999-2005) was designed. A univariate and multivariate logistic regression was performed to identify the risk factors for suffering a NP due to MRSA. Demographic factors, related to hospitalization, immunosuppression or neutropenia, to medication and severity were included.


RESULTS
Three hundred and sixty three patients (121 cases and 242 controls) were studied. The final model of multivariate logistic regression included an age>14 years (OR 7.4, CI 95% 1.5-37.4, P<.015), NP appearance>6 days after admittance (OR 4.1, CI 95% 2.4-7,1, P<.001), NP development excluding summers (OR 2.5, CI 95% 1.2-5.2, P<.015), respiratory diseases (OR 4.9, CI 95% 1.5-15.8, P<.007) and multilobar involvement (OR 4, CI 95% 2.3-7.2, P<.001).The probability of developing a pneumonia due to MRSA was studied for each of the possible combinations and subsequently classified in minor and major criteria.


CONCLUSIONS
MRSA coverage should be included in the empirical treatment of NP when: a) an adult patient (>14 years old) presents, at least, 2 major criteria or 1 major criterion together with 2 minor criteria, and b) a patient <14 years-old has 2 major criteria as well as 2 minor criteria.
Unidad Clínica de Enfermedades Infecciosas, Hospital Universitario Reina Sofía, Córdoba, España.
Julián
J
Torre-Cisneros
Rocío
R
Tejero García
Clara
C
Natera Kindelán
Pilar
P
Font Ugalde
Francisco
F
Franco Álvarez de Luna
Juan José
JJ
Castón Osorio
Antonio
A
Rivero Román
Manuel
M
Casal Román
D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D003428:Cross Infection / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus; D008875:Middle Aged; D011023:Pneumonia, Staphylococcal / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D011336:Probability; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality