Usefulness of procalcitonin clearance as a prognostic biomarker in septic shock. A prospective pilot study

PCT, IL-6, and IL-10 facilitate early diagnosis and pathogen classifications in bloodstream infection

BACKGROUND

In the diagnosis of bloodstream infection (BSI), various inflammatory markers such as C-reactive protein (CRP), procalcitonin (PCT), interleukins (IL), white blood cell count (WBC), neutrophil percentage (NE%), platelet count (PLT), and erythrocyte sedimentation rate (ESR) have been extensively utilized. However, their specific roles in distinguishing BSI from local bacterial infection (LBI) and in classifying BSI pathogens remain uncertain.

METHODS

A historical cohort study was conducted, involving the enrollment of 505 patients with BSI and 102 patients with LBI. To validate the reliability of the clinical data obtained from this cohort, mouse models of BSI were utilized.

RESULTS

Our findings revealed that patients with BSI had significantly higher levels of inflammatory markers, including CRP, PCT, IL-6, IL-10, WBC, NE%, and ESR, compared to those with LBI (p < 0.05). The receiver operating characteristic (ROC) curve analysis demonstrated that CRP, PCT, IL-6, IL-10, ESR and NE% exhibited excellent diagnostic efficacy for BSI. Additionally, we observed significant differences in CRP, PCT, IL-6, and IL-10 levels between patients with BSI caused by Gram-positive bacteria (GP-BSI) and Gram-negative bacteria (GN-BSI), but no significant variations were found among specific bacterial species. Furthermore, our study also found that CRP, PCT, and IL-10 have good discriminatory ability for vancomycin-resistant Enterococcus (VRE), but they show no significant diagnostic efficacy for other multidrug-resistant organisms (MDROs) such as carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA). In our mouse model experiments, we observed a remarkable increase in PCT, IL-6, and IL-10 levels in mice with GN-BSI compared to those with GP-BSI.

CONCLUSION

Our study has confirmed that PCT, IL-6, and IL-10 are efficient biomarkers for distinguishing between BSI and LBI. Furthermore, they can be utilized to classify BSI pathogens and differentiate between VRE and vancomycin-susceptible Enterococcus. These findings are extremely valuable for clinicians as they enable timely initiation of empiric antibiotic therapies and ultimately lead to improved clinical outcomes for patients with BSI.

Ratio of serum procalcitonin to monocytic HLA-DR as a reliable parameter in prognosis prediction of sepsis

BACKGROUND

We evaluated the prognostic potential of the ratio of serum procalcitonin to monocytic HLA-DR for 28-day mortality in sepsis.

METHODS

In this retrospective study, a total of 91 patients with sepsis were enrolled. Clinical and laboratory data detected on admission (D0) and 7 days thereafter (D7) including the Acute Physiology and Chronic Health Evaluation II (APACHE II), the Sequential Organ Failure Assessment (admission SOFA), serum lactate, D-dimer, mHLA-DR, procalcitonin, platelet and white blood cell count, neutrophil-to-lymphocyte ratio were collected. The PCT/mHLA-DR ratio, the changes in mHLA-DR and WBC on day 7 compared with those on the day of admission and PCT clearance were calculated. Receiver operating characteristic curves, Kaplan-Meier survival curves, DeLong test and Cox regression analyses were used to assess and compare their predictive values.

RESULTS

Among all studied parameters, D₇-PCT/mHLA-DR showed the best discriminatory property to differentiate survivors from non-survivors and was identified as an independent predictor of 28-day mortality.

CONCLUSION

The D₇-PCT/mHLA-DR ratio was more sensitive than either biomarker alone in predicting fatal outcome in septic patients. Combining pro-inflammatory and immunosuppression biomarkers might improve the prognostic accuracy in sepsis.

Procalcitonin kinetics as a prognostic marker in severe sepsis/septic shock

BACKGROUND AND AIMS

To evaluate the prognostic value of change (fall) in serum procalcitonin level (PCT) in critically ill adults with severe sepsis/septic shock.

METHODS

This was a prospective observational study in a general purpose Intensive Care Unit of a teaching Institute. PCT was measured at admission (D0) and after 72-96 h (D4) by electrochemi-luminescence immunoassay (BRAHMS PCT kit) in adults (>18 years) admitted with severe sepsis or septic shock. Change in procalcitonin values from D0 to D4 was correlated with the primary outcome, that is, 28 days mortality. All results are reported as median (interquartile range).

RESULTS

A total of 171 (100 males) of 181 patients were included. The median age was 46 years (range 19-79). 137 patients were in septic shock and 34 in severe sepsis. The sequential organ failure assessment (SOFA) score in all patients was 11 (9-14).91 (53.2%) patients survived at 28 days (survivors). The baseline procalcitonin was similar in two groups (3.48 [1.04-15.85] vs. 5.27 [1.81-23.57] ng/ml in survivors and nonsurvivors [NS] respectively). The procalcitonin change was 1.58 (0.20-8.52) in survivors and 0.28 (-1.38-6.17) in NS (P = 0.01). The C-statistic of percentage change in procalcitonin from D0 to D4 to predict survival was 0.73 (95% confidence interval [CI]: 0.65-0.82) when compared to 0.78 (95% CI: 0.71-0.86) for change of SOFA score. For an absolute fall in procalcitonin of >1 ng/ml, a 70% fall predicted survival with 75% sensitivity and 64% specificity.

CONCLUSIONS

In critically ill-patients with severe sepsis/septic shock, change (fall) in procalcitonin is associated with good outcome.