TABLE 1.

Indicators of mupirocin usage across functional eras at the VAMC^a

Era	No. of prescriptions per:			No. of MRSA isolatesb
	1,000 Patient days	Yr	Individual
1	2.9	400	2.24	1.13
2	3.0	400	2.30	0.85
3	2.6	256	1.00	0.32
4	0.7	53	0.20	0.04
5	0.1	9	0.04	0.02

^aEra 1, introduction of mupirocin; era 2, unrestricted use; era 3, judicious use recommended; eras 4 and 5, early and later periods of administrative control. Numbers of individuals were tallied as unique occurrences of individuals with MRSA within eras, but individuals may recur between eras. Regression coefficients (r values) are as follows: for number of prescriptions per 1,000 patient days, −0.92; per year, −0.96; and per individual, −0.95; and for number of MRSA isolates, −0.96. Associated probabilities (P values) are as follows: for number of prescriptions per 1,000 patient days, 0.03; per year, 0.01; and per individual, 0.01; and for number of MRSA isolates, <0.01.

^bNumber of MRSA isolates isolated by the hospital laboratory.