RT Journal Article
SR Electronic
T1 A Poisson-based Prediction Model and Warning System for MRSA Daily Burden
JF American Society for Clinical Laboratory Science
JO Clin Lab Sci
FD American Society of Chemistry and Laboratory Science
SP 22
OP 25
DO 10.29074/ascls.22.1.22
VO 22
IS 1
A1 Perla, Rocco J
A1 Allen, Bradford D
YR 2009
UL http://hwmaint.clsjournal.ascls.org/content/22/1/22.abstract
AB OBJECTIVE: This study was designed to demonstrate that the number of methicillin-resistant Staphylococcus aureus (MRSA) isolates collected daily in a community hospital is Poisson distributed and that using a one-sided Poisson control table is a fast and easy way to recognize unusually high numbers of MRSA isolates collected daily that may signal possible outbreaks.METHODS: A retrospective analysis of MRSA isolates collected daily over a three year period (2005-2007, N = 934) was performed. Observed MRSA isolate frequencies are compared to Poisson frequencies using chi-square goodness-of-fit tests. A regression equation on the mean number of MRSA isolates collected daily for the years 2005, 2006, and 2007 is used to predict the mean number of MRSA isolates for 2008. A warning system for MRSA isolates collected daily is presented and a one-tailed, mean + 2 sigma control table is provided.SETTING: One-hundred-fifty bed community hospital in central Massachusetts.RESULTS: Goodness-of-fit tests showed close agreement between actual MRSA isolates collected daily and Poisson frequencies for 2005 (χ24 = 4.045, p = 0.39), 2006 (χ24 = 2.807, p = 0.59), and 2007 (χ24 = 1.494, p = 0.83).CONCLUSION: Theoretical and empirical support is provided for the Poisson probability model. The model can be used to identify unusually high occurrences of MRSA isolates collected daily. This study was limited to a single community healthcare system but the results may be generalized to other types of healthcare settings.ABBREVIATIONS: ICPs = infection control practitioners; MDROs = multi-drug resistant organisms; MRSA = methicillin-resistant Staphylococcus aureus.