Routine blood cultures in the management of community acquired pneumonia; is it necessary?

INTRODUCTION: The role of blood cultures (BCs) in the management of community acquired pneumonia (CAP) has generated a lot of controversy among clinicians in recent times. The main objectives of this audit were to determine if BC results impact the choice of antibiotics, and hospital outcomes in CAP. MATERIALS AND METHODS: This was a retrospective study of adults with CAP treated in the ED of Goulbourn Valley Base Hospital, Shepparton in Australia from November 2010 to November 2011. RESULTS: Two hundred and twenty five patients were treated for CAP during the period in review with a mean age of 67.09±19.82 yrs and male:female of 1.5:1. 277 sets of BCs were performed and only 2.2% of the cases had true positive BCs .87% of the total cost of performing these BCs was spent on those with negative cultres.15.1% of the cases had their antibiotics changed during their hospitalization but the results of the BCs had no impact on the antibiotic change. Even though not statistically significant true positive BCs was associated with prolong length of hospital stay (7.6 ± 9.39 days vs 4.89 ± 3.24 days, p=0.44), and duration of IV antibiotic use (4.8±3.27 days vs 3.58±1.97 days, p=0.39). But the case fatality rate was much lower in those with positive BCs, (0 vs 5.7%,p< 0.05). Tachycardia (>120.4±12.46 bpm), neutrophilia (15.0± 8.16 /ul), and high CRP (326.4±146.32 ug/l) were predictors of true positive BCs. CONCLUSIONS: Routine BCs in the management of CAP is not cost-effective with large portion of the cost spent on cultures that returned negative result .Therefore it use show be limited to those likely to return positive cultures. DOI: http://dx.doi.org/10.3126/ijim.v1i2.7408 Int J Infect Microbiol 2012;1(1):54-57