Role of procalcitonin and C-reactive protein in differentiation of mixed bacterial infection from 2009 H1N1 viral pneumonia

Abstract

Please cite this paper as: Ahn et al. (2011) Role of procalcitonin and C‐reactive protein in differentiation of mixed bacterial infection from 2009 H1N1 viral pneumonia. Influenza and Other Respiratory Viruses 5(6), 398–403. Background Mixed bacterial infection is an important contributor to morbidity and mortality during influenza pandemics. We evaluated procalcitonin (PCT) and C‐reactive protein (CRP) in differentiating pneumonia caused by mixed bacterial and 2009 H1N1 influenza infection from 2009 H1N1 influenza infection alone. Methods Data were collected retrospectively over a 7‐month period during the 2009 H1N1 influenza pandemic. Patients visiting emergency department and diagnosed as community‐acquired pneumonia caused by 2009 H1N1 infection were included (n = 60). Results Mixed bacterial and viral infection pneumonia (n = 16) had significantly higher PCT and CRP levels than pneumonia caused by 2009 H1N1 influenza alone (n = 44, P = 0·019, 0·022 respectively). The sensitivity and specificity for detection of mixed bacterial infection pneumonia was 56% and 84% for PCT > 1·5 ng/ml, and 69% and 63% for CRP > 10 mg/dl. Using PCT and CRP in combination, the sensitivity and specificity were 50% and 93%, respectively. Conclusion Procalcitonin and CRP alone and their combination had a moderate ability to detect pneumonia of mixed bacterial infection during the 2009 H1N1 pandemic. Considering high specificity, combination of low CRP and PCT result may suggest that pneumonia is unlikely to be caused by mixed bacterial infection.

Combination of procalcitonin and C‐reactive protein levels in the early diagnosis of bacterial co‐infections in children with H1N1 influenza

“…A previous study using a combination of CRP and PCT levels to evaluate bacterial co‐infections observed increased accuracy in differentiating children with bacterial co‐infections from those infected with H1N1 alone . Similar observations were reported in the present study, in which we used a multivariate logistic regression analysis to construct a new model using PCT and CRP levels: [Logit( P ) = −1.912 + 0.546 PCT + 0.087 CRP].…”

“…Our study showed that serum CRP levels were significantly higher in patients with bacterial co‐infection compared with those infected with H1N1 alone, indicating that these biomarkers may useful in discriminating between these conditions. Interestingly, for the optimal cutoff value, the NPV of CRP (0.971) alone is considerably higher, in line with one previous study . This suggests that clinicians might consider using CRP to rule out patients who are free of co‐infections.…”

“…Haran et al found that CRP served as a predictor of bacterial infection among patients with H1N1 infection. Similarly, Shin et al reported that serum CRP levels were significantly higher in patients with bacterial co‐infection compared with those infected with H1N1 alone. However, another study suggested that CRP levels were not useful for distinguishing bacterial co‐infections from H1N1 infections .…”

“…The diagnostic and predictive value of serum PCT and CRP levels as biomarkers has been discussed in several studies . Shin et al found that serum PCT was a good indicator in discriminating bacterial co‐infections from H1N1 infection alone in 60 adult patients in ICU. Guervilly et al reported that PCT values were significantly higher in patients with bacterial co‐infections.…”

“…The diagnostic utility of CRP to differentiate bacterial co‐infection from H1N1 infection is disputed . Haran et al found that CRP served as a predictor of bacterial infection among patients with H1N1 infection.…”