A long-term forecast of MRSA daily burden using logistic modeling.
OBJECTIVE
This article presents a logistic model that describes the mean number of unique methicillin-resistant Staphylococcus aureus (MRSA) isolates collected daily at a 150-bed community hospital in central Massachusetts. The model is used to derive a long-term forecast of the mean MRSA isolate frequency.


METHODS
The mean number of MRSA isolates collected daily was found for each quarter from the first quarter of 1996 to the first quarter of 2008. A logistic model was fit to the data and then extrapolated to obtain a long-term forecast.


METHODS
Data was collected at a one-hundred-fifty bed community hospital in central Massachusetts.


RESULTS
The coefficient of determination indicates that 87% of the variation in transformed data is explained by the model. The extrapolated logistic model prediction is that the mean number of MRSA isolates collected daily approaches 1.42 MRSA isolates per day.


CONCLUSIONS
Logistic modeling of empirical data using modest mathematical assumptions is an effective way to understand, visualize, and forecast MRSA daily frequencies over time. The advantage for laboratorians and epidemiologists is that logistic models provide reliable trending and long-term prediction ability of multi-drug resistant organism frequencies. Moreover, as additional data is obtained, the logistic model assumptions can be checked, the model updated, and forecasts improved.
Allen
Bradford D
BD
Department of Mathematics and Science, Lasell College, 1844 Commonwealth Avenue, Newton, MA 02466, USA. ballen@lasell.edu
Perla
Rocco J
RJ
D003428:Cross Infection / Q000453:epidemiology*; D006764:Hospitals, Community; D006801:Humans; D016015:Logistic Models; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D011159:Population Surveillance / Q000379:methods*; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology