Ruiz-Giardin Jose Manuel, Noguerado Arturo, Delgado-Iribarren Alberto, Valverde-Cánovas José Francisco, Aranda-Cosgaya Carlos, Delgado-Yagüe María, del Rey María del Carmen, García Isabel, Jaquetti Jerónimo, Pérez Alejandro
Medicina Interna-Infecciosas, Hospital Universitario de Fuenlabrada, Madrid, España.
Enferm Infecc Microbiol Clin. 2010 Aug-Sep;28(7):421-9. doi: 10.1016/j.eimc.2009.09.011. Epub 2010 Mar 23.
Anaerobic bacteremias are uncommon. There is no agreement on their clinical predictability and the usefulness of anaerobic blood cultures. The objective of this study was to develop and validate a model for the prediction of anaerobic bacteremias.
The developing model was created with 984 bacteremias (45 anaerobic bacteremias) during 1985-1986 and 1996-1997. The validation model was made with 320 bacteremias during 2005-2006.
Independent multivariate predictors of true anaerobic bacteremia were used to develop a model stratifying patients with scores of 0 to 13 points(p), which were: unknown focus OR 3.46 (CI: 1.13-10.54) 3 p; abdominal and skin focus OR 14.85 (CI: 6.37-34.62) 6p; hypotension OR 1.99 (CI: 0.98-4.04) 2p; absence of vascular manipulations OR 2.62 (CI: 1.04-6.60) 2p and age over 60 years OR 3.21 (CI: 1.19-8.67) 3p. In the derivation sets group with more than 7p the model had Sensitivity: 77.8%, Specificity: 78.3%, PPV:14.7%, and a NPV of 98.6%. The area under curve was ROC=0.84 (SE=0.011), 95% CI: 0.82-0.86 with an anaerobic bacteremia prevalence of 4.6%. The validation set was studied analysing 320 bacteremias. Of these, 83.6% (95% CI: 71.19%-92.23%) of anaerobic bacteremias had more than 7 points, and 72.7% had more than 9 points. There was 26.4% (95% CI: 21.2%-32.15%) aerobic and facultative anaerobic bacteremias with more than 7 points, and only the 11.7% with 9 or more points. The area under the curve was, ROC=0.82 (SE=0.02), 95% CI:0.78-0.86, and estimated prevalence, 2%.
Abdominal and skin focus OR 14,85; unknown focus OR 3,46; hypotension OR 1,99; absence of vascular manipulations OR 2,62 and age over 60 years enable us to make a predictive clinical model of probability of anaerobic bacteremia with a high sensitivity and specificity. The model particularly has a significant predictive negative value due to the low prevalence of anaerobic bacteremia.
