The Value of ID Consultation for Staphylococcus aureus (SA) Bacteremia

Background: SA bacteremia requires timely and appropriate management.  Key steps in treatment include appropriate antibiotic choice and duration, serial blood cultures, echocardiography, and removal of any focal source.  ID consultation has been advocated to optimize care.

Methods: All inpatients aged ≥ 18 years with documented blood cultures positive for SA at an Orlando Health facility between January 1 and December 31, 2011 were screened. Exclusion criteria included survival ≤ 48 hours from index culture. Included patients underwent comprehensive retrospective chart review for outcomes, stratified by presence or absence of ID consultation.  Statistical analyses were performed with SPSS v20 software, with continuous and nominal data evaluated with the student’s t-test and Chi-squared test respectively.

Results: A total of 191 bacteremias were screened; 177 were included. ID consultation was obtained in 141 (80%). Follow-up blood cultures and echocardiography occurred more often with ID consultation (94% vs 58%, p<0.001 and 74% vs 36%, p<0.001 respectively). Focal source was identified in 74% and 61% of patients, with subsequent removal in 79% and 53% respectively (p=0.021). Duration of therapy was twice as long with ID consultation (27 vs 12 days, p=0.02). Overall mortality was significantly improved with ID consultation (7% vs 22%, p=0.007). Mortality related to SA bacteremia approached significance at 6% vs 11% (p=0.06).

 

Parameter	ID Consult (n = 141)	No ID Consult (n = 36)	p-value
Index culture MRSA	77 (55%)	13 (36%)	0.048
Follow up Blood Cultures	132 (94%)	21 (58%)	<0.001
Focal Source Removed, yes	76 (79%)1	9 (53%)2	0.021
Echocardiography	105 (74%)	13 (36%)	<0.001
Duration of therapy, days (mean)	27.2	12.4	0.02
Overall Mortality	10 (7%)	8 (22%)	0.007
Mortality related to SA bacteremia	9 (6.4%)	4 (11.1%)	0.06
*results expressed as n (%) unless otherwise specified;   1 n=96;  2n = 17

Conclusion: SA bacteremia management by an ID consultant results in improved use of best practices and lower mortality.