Procalcitonin-guided algorithms of antibiotic therapy in the intensive care unit: A systematic review and meta-analysis of randomized controlled trials:

The role of biomarkers in low respiratory tract infections

Low respiratory tract infections (LRTI) represent the leading infectious cause of death worldwide and account for substantial use of healthcare resources. Physicians must adopt practices focused on improving outcomes and serum biomarker can help them in the management of patients with LRTI. Several studies have been carried out or are currently ongoing to evaluate the role of various biomarkers for the differential diagnosis, definition of prognosis, treatment and duration of antibiotic therapy in respiratory infections. The objective of this position paper of the Italian Society of Respiratory Diseases (SIMER) is to provide evidence-based recommendations for the use of biomarkers in routine clinical practice in the management of adult patients with LRTI. These guidelines capture the use of biomarkers both outside and inside the hospital, focused on community-acquired pneumonia, acute exacerbations of chronic obstructive pulmonary disease, hospital-acquired and ventilator-acquired pneumonia.

Clinical features of cyst infection and hemorrhage in ADPKD: new diagnostic criteria

BACKGROUND AND OBJECTIVES

Cyst infection and cyst hemorrhage are frequent and serious complications of autosomal dominant polycystic kidney disease (ADPKD), often being difficult to diagnose and treat. The first objective of this study is to clarify the clinical features of ADPKD patients with cyst hemorrhage or infection. The second objective is to establish diagnostic criteria for ADPKD patients with cyst infection or cyst hemorrhage.

PATIENTS AND METHODS

Patients with definite cyst infection or hemorrhage were enrolled from among the ADPKD patients referred to us between January 2004 and October 2011. We investigated their symptoms, laboratory data, and the computed tomography (CT)/magnetic resonance imaging (MRI) features of infected cysts (before and after onset), normal cysts, and cysts with hemorrhage.

RESULTS

There were 24 patients with cyst infection (36 infected cysts) and 12 patients with acute cyst hemorrhage (13 bleeding cysts). White blood cell (WBC) count >10,000/μl, serum C-reactive protein (CRP) >15.0 mg/dl, and body temperature >38 °C strongly suggested cyst infection. All of the cysts with hemorrhage contained a high-density mass-like area or showed overall high density on CT, and all patients with cyst hemorrhage had abdominal pain or gross hematuria. On the other hand, infected cysts showed an increase of intensity on MRI [diffusion-weighted imaging (DWI)], while a fluid-fluid level, wall thickening, and gas were also evidence of infection. Abdominal pain and/or sequential changes on MRI after onset of symptoms were useful for localizing infected cysts.

CONCLUSION

Acute cyst hemorrhage and infection can be identified from symptoms, laboratory data, and CT/MRI findings.

Role of procalcitonin in managing adult patients with respiratory tract infections

Respiratory infections remain the most common reason why patients seek medical care in ambulatory and hospital settings, and they are the most frequent precursor of sepsis. In light of the limitations of clinical signs and symptoms and traditional microbiologic diagnostics for respiratory infections, blood biomarkers that correlate with the presence and extent of bacterial infections may provide additional useful information to improve diagnostic and prognostic efforts and help with therapeutic decisions in individual patients. A growing body of evidence supports the use of procalcitonin (PCT) to differentiate bacterial from viral respiratory diagnoses, to help risk stratify patients, and to guide antibiotic therapy decisions about initial need for, and optimal duration of, therapy. Although still relatively new on the clinical frontier, a series of randomized controlled trials have evaluated PCT protocols for antibiotic-related decision making and have included patients from different clinical settings and with different severities of respiratory infection. In these trials, initial PCT levels were effective in guiding decisions about the initiation of antibiotic therapy in lower-acuity patients, and subsequent measurements were effective for guiding duration of therapy in higher-acuity patients, without apparent harmful effects. Recent European respiratory infection guidelines now also recognize this concept. As with any other laboratory test, PCT should not be used on a stand-alone basis. Rather, it must be integrated into clinical protocols, together with clinical, microbiologic data and with results from clinical risk scores. The aim of this review is to summarize recent evidence about the usefulness of PCT in patients with lower respiratory tract infections and to discuss the potential benefits and limitations of this marker when used for clinical decision making.

[Update: studies in intensive care medicine. Results of the last 12 months]

Die Intensivmedizin spielt eine bedeutende Rolle sowohl für den medizinischen als auch den ökonomischen Erfolg eines Krankenhauses. Eine qualitativ hochwertige Intensivmedizin setzt die Kenntnis und die Umsetzung relevanter neuer klinischer Studien voraus. Die vorliegende Arbeit gibt einen Überblick über die wichtigsten intensivmedizinischen Publikationen des Jahres 2010 und der ersten Jahreshälfte von 2011 und ordnet diese im Hinblick auf die jeweilige klinische Relevanz ein. In den Jahren 2010 und 2011 sind zahlreiche randomisierte Studien veröffentlicht worden. Schwerpunkte waren die Therapie des Lungenversagens, die Analgosedierung und die Sepsistherapie.

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

OBJECTIVE

To evaluate procalcitonin clearance as a prognostic biomarker in septic shock.

DESIGN

Prospective, observational pilot study.

SETTING

Intensive care unit.

PATIENTS

Patients admitted to the ICU due to septic shock and multiorgan dysfunction.

INTERVENTIONS

Serum concentrations of procalcitonin were determined within 12h of onset of septic shock and multiorgan dysfunction (coinciding with admission to the ICU), and the following extractions were obtained after 24, 48 and 72h in patients who survived.

DATA COLLECTED

Demographic data, Acute Physiology and Chronic Health Evaluation II score, and Sequential Organ Failure Assessment score, data on the primary focus of infection, and patient outcome (ICU mortality).

RESULTS

Procalcitonin clearance was higher in survivors than in non-survivors, with significant differences at 24h (73.9 [56.4-83.8]% vs 22.7 [-331-58.4], p<0.05) and 48h (81.6 [71.6-91.3]% vs -7.29 [-108.2-82.3], p<0.05). The area under the ROC curve was 0.74 (95%CI, 0.54-0.95, p<0.05) for procalcitonin clearance at 24h, and 0.86 (95%CI, 0.69-1.0, p<0.05) at 48h.

CONCLUSIONS

ICU mortality was associated to sustained high procalcitonin levels, suggesting that procalcitonin clearance at 48h may be a valuable prognostic biomarker.

Appraising contemporary strategies to combat multidrug resistant gram-negative bacterial infections--proceedings and data from the Gram-Negative Resistance Summit

The emerging problem of antibiotic resistance, especially among Gram-negative bacteria (GNB), has become a serious threat to global public health. Very few new antibacterial classes with activity against antibiotic-resistant GNB have been brought to market. Renewed and growing attention to the development of novel compounds targeting antibiotic-resistant GNB, as well as a better understanding of strategies aimed at preventing the spread of resistant bacterial strains and preserving the efficacy of existing antibiotic agents, has occurred. The Gram-Negative Resistance Summit convened national opinion leaders for the purpose of analyzing current literature, epidemiologic trends, clinical trial data, therapeutic options, and treatment guidelines related to the management of antibiotic-resistant GNB infections. After an in-depth analysis, the Summit investigators were surveyed with regard to 4 clinical practice statements. The results then were compared with the same survey completed by 138 infectious disease and critical care physicians and are the basis of this article.

Short-course versus prolonged-course antibiotic therapy for hospital-acquired pneumonia in critically ill adults

BACKGROUND

Pneumonia is the most common hospital-acquired infection affecting patients in the intensive care unit (ICU). However, the optimal duration of antibiotic therapy for hospital-acquired pneumonia (HAP) is uncertain.

OBJECTIVES

To assess the effectiveness of short versus prolonged-course antibiotic administration for HAP in critically ill adults, including patients with ventilator-associated pneumonia (VAP).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1950 to February week 4, 2011), EMBASE (1974 to March 2011), LILACS (1985 to March 2011) and Web of Science (1985 to March 2011).

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) comparing fixed durations of antibiotic therapy, or comparing a protocol intended to limit duration of therapy with standard care, for HAP (including patients with VAP) in critically ill adults.

DATA COLLECTION AND ANALYSIS

Two review authors conducted data extraction and assessment of risk of bias. We contacted trial authors for additional information.

MAIN RESULTS

Eight studies (1703 patients) were included. Methodology varied considerably and we found little evidence regarding patients with a high probability of HAP who were not mechanically ventilated. For patients with VAP, a short seven to eight-day course of antibiotics compared with a prolonged 10 to 15-day course (three studies, N = 508) increased 28-day antibiotic-free days (odds ratio (OR) 4.02; 95% confidence interval (CI) 2.26 to 5.78) and reduced recurrence of VAP due to multi-resistant organisms (OR 0.44; 95% CI 0.21 to 0.95), without adversely affecting other outcomes. However, for cases of VAP due to non-fermenting Gram-negative bacilli (NF-GNB), recurrence was greater after short-course therapy (OR 2.18; 95% CI 1.14 to 4.16; two studies, N = 176), though other outcome measures did not significantly differ. Discontinuation strategies utilising clinical features (one study; N = 302) or procalcitonin (three studies; N = 323) led to a reduction in duration of therapy and, in the procalcitonin studies, increased 28-day antibiotic-free days (mean difference (MD) 2.80; 95% CI 1.39 to 4.21) without negatively affecting other outcomes.

AUTHORS' CONCLUSIONS

We conclude that for patients with VAP not due to NF-GNB, a short fixed-course (seven or eight days) antibiotic therapy may be more appropriate than a prolonged course (10 to 15 days). Use of an individualised strategy (incorporating clinical features or serum procalcitonin) appears to safely reduce duration of antibiotic therapy for VAP.

Inflammatory biomarkers for the diagnosis, monitoring and follow-up of community-acquired pneumonia: clinical evidence and perspectives

Community-acquired pneumonia (CAP) is defined as an infection of the alveolar or gas-exchanging portions of the lungs occurring outside the hospital, with clinical symptoms accompanied by the presence of an infiltrate in the chest radiograph. Due to the high prevalence and the large demand of healthcare resources, an accurate clinical and therapeutic decision making is crucial in patients with CAP. As such, there is increasing interest on the use of traditional and innovative biomarkers such as procalcitonin (PCT) and C-reactive protein (CRP). At variance with other traditional inflammatory and innovative biomarkers, PCT might help limiting unnecessary antibiotic use, reduce bacterial resistance and decrease medical costs and drug-related adverse events. PCT however carries some additional advantages over CRP, such as the greater specificity for infections and a more narrow range of normal concentrations.

Meta-analysis and systematic review of procalcitonin-guided therapy in respiratory tract infections

Circulating procalcitonin (PCT) is a biomarker that can be used in diagnosing bacterial infections. We performed a quantitative meta-analysis of available randomized controlled trials to determine whether antibiotic therapy based on PCT measurements alters clinical outcomes and antibiotic use in patients with lower respiratory tract infections. We identified studies through MEDLINE (1996 to 2010), the ISI Web of Knowledge (1996 to 2010), and Ovid. Studies that met our criteria were prospective, randomized controlled trials involving patients with respiratory tract infections. Outcomes of mortality, intensive care unit (ICU) admission, length of hospital stay, number of antibiotic prescriptions, and duration of antibiotic treatment were evaluated. Eight studies randomizing 3,431 patients met our criteria for inclusion. Pooled analysis showed a significant reduction in number of antibiotic prescriptions and duration of antibiotic use in patients with PCT-guided antibiotic treatment compared to standard therapy. In addition, the use of PCT-guided antibiotic therapy did not impact mortality, ICU admission, or length of hospital stay in these studies. A high degree of heterogeneity was identified in 3 of 5 outcomes that were evaluated, and sensitivity analysis indicated that heterogeneity was decreased among studies using the same PCT-based treatment algorithm. In conclusion, PCT-guided antibiotic therapy in patients with respiratory tract infections appears to reduce antibiotic use without affecting overall mortality or length of stay in the hospital.

Procalcitonin for reduced antibiotic exposure in the critical care setting: a systematic review and an economic evaluation

OBJECTIVE

Procalcitonin may be associated with reduced antibiotic usage compared to usual care. However, individual randomized controlled trials testing this hypothesis were too small to rule out harm, and the full cost-benefit of this strategy has not been evaluated. The purpose of this analysis was to evaluate the effect of a procalcitonin-guided antibiotic strategy on clinical and economic outcomes.

INTERVENTIONS

The use of procalcitonin-guided antibiotic therapy.

METHODS AND MAIN RESULTS

We searched computerized databases, reference lists of pertinent articles, and personal files. We included randomized controlled trials conducted in the intensive care unit that compared a procalcitonin-guided strategy to usual care and reported on antibiotic utilization and clinically important outcomes. Results were qualitatively and quantitatively summarized. On the basis of no effect in hospital mortality or hospital length of stay, a cost or cost-minimization analysis was conducted using the costs of procalcitonin testing and antibiotic acquisition and administration. Costs were determined from the literature and are reported in 2009 Canadian dollars. Five articles met the inclusion criteria. Procalcitonin-guided strategies were associated with a significant reduction in antibiotic use (weighted mean difference -2.14 days, 95% confidence interval -2.51 to -1.78, p < .00001). No effect was seen of a procalcitonin-guided strategy on hospital mortality (risk ratio 1.06, 95% confidence interval 0.86-1.30, p = .59; risk difference 0.01, 95% confidence interval -0.04 to +0.07, p = .61) and intensive care unit and hospital lengths of stay. The cost model revealed that, for the base case scenario (daily price of procalcitonin Can$49.42, 6 days of procalcitonin measurement, and 2-day difference in antibiotic treatment between procalcitonin-guided therapy and usual care), the point at which the cost of testing equals the cost of antibiotics saved is when daily antibiotics cost Can$148.26 (ranging between Can$59.30 and Can$296.52 on the basis of different assumptions in sensitivity analyses).

CONCLUSIONS

Procalcitonin-guided antibiotic therapy is associated with a reduction in antibiotic usage that, under certain assumptions, may reduce overall costs of care. However, the overall estimate cannot rule out a 7% increase in hospital mortality.

Measurement of granulocyte maturation may improve the early diagnosis of the septic state

BACKGROUND

Sepsis is a costly diagnosis in hospitalized patients. Failure to diagnose sepsis in a timely manner creates a potential financial and safety hazard. The use of transthyretin, C-reactive protein and procalcitonin measurement as early markers of systemic inflammatory response syndrome (SIRS) and sepsis in association with admission of emergency department patients to the intensive care unit (ICU) has been studied. In these studies the SIRS criteria as well as the use of an elevated neutrophil count with granulocyte precursors (left shift) have proved to be problematic. Despite the validity of procalcitonin measurement (PCT, Brahms) in the early diagnosis of SIRS the cost and time for testing are limiting considerations. Immature granulocyte (IG) measurement has been proposed as a more readily available indicator of the presence of granulocyte precursors (left shift).

METHODS

This study calibrates and validates the measurement of granulocyte maturation [Immature granulocytes (IG)] to the identification of sepsis, a study carried out on a Sysmex Analyzer, model XE 2100 (Kobe, Japan). The Sysmex IG parameter is a crucial measure of immature granulocyte counts and includes metamyelocytes and myelocytes, but not band neutrophils.

RESULTS AND CONCLUSIONS

We found agreement with previous work that designated an IG measurement cut-off of 3.2 as optimal. The analysis was then carried a step further with a multivariable discriminator.

Antimicrobial stewardship: attempting to preserve a strategic resource

Antimicrobials hold a unique place in our drug armamentarium. Unfortunately the increase in resistance among both gram-positive and gram-negative pathogens coupled with a lack of new antimicrobial agents is threatening our ability to treat infections. Antimicrobial use is the driving force behind this rise in resistance and much of this use is suboptimal. Antimicrobial stewardship programs (ASP) have been advocated as a strategy to improve antimicrobial use. The goals of ASP are to improve patient outcomes while minimizing toxicity and selection for resistant strains by assisting in the selection of the correct agent, right dose, and best duration. Two major strategies for ASP exist: restriction/pre-authorization that controls use at the time of ordering and audit and feedback that reviews ordered antimicrobials and makes suggestions for improvement. Both strategies have some limitations, but have been effective at achieving stewardship goals. Other supplemental strategies such as education, clinical prediction rules, biomarkers, clinical decision support software, and institutional guidelines have been effective at improving antimicrobial use. The most effective antimicrobial stewardship programs have employed multiple strategies to impact antimicrobial use. Using these strategies stewardship programs have been able to decrease antimicrobial use, the spread of resistant pathogens, the incidence of C. difficile infection, pharmacy costs, and improved patient outcomes.

In Critically Ill Patients, Serum Procalcitonin Is More Useful in Differentiating between Sepsis and SIRS than CRP, Il-6, or LBP

We studied the usefulness of serum procalcitonin (PCT), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP) levels and C-reactive protein (CRP) levels, in differentiating between systemic inflammatory response syndrome (SIRS) and sepsis in critically ill patients. Methods. In this single centre prospective observational study we included all consecutive patients admitted with SIRS or sepsis to the ICU. Blood samples for measuring CRP, PCT, IL-6 and LBP were taken every day until ICU discharge. Results. A total of 76 patients were included, 32 with sepsis and 44 with SIRS. Patients with sepsis were sicker on admission and had a higher mortality. CRP, PCT, IL-6 and LBP levels were significantly higher in patients with sepsis as compared to SIRS. With PCT levels in the first 24 hours after ICU admission <2 ng/mL, sepsis was virtually excluded (negative predictive value 97%). With PCT >10 ng/mL, sepsis with bacterial infection was very likely (positive predictive value 88%). PCT was best at discriminating between SIRS and sepsis with the highest area under the ROC curve (0.95, 95% CI 0.90-0.99). Discussion. This study showed that PCT is more useful than LBP, CRP and IL-6 in differentiating sepsis from SIRS.

In Critically Ill Patients, Serum Procalcitonin Is More Useful in Differentiating between Sepsis and SIRS than CRP, Il-6, or LBP

We studied the usefulness of serum procalcitonin (PCT), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP) levels and C-reactive protein (CRP) levels, in differentiating between systemic inflammatory response syndrome (SIRS) and sepsis in critically ill patients. Methods. In this single centre prospective observational study we included all consecutive patients admitted with SIRS or sepsis to the ICU. Blood samples for measuring CRP, PCT, IL-6 and LBP were taken every day until ICU discharge. Results. A total of 76 patients were included, 32 with sepsis and 44 with SIRS. Patients with sepsis were sicker on admission and had a higher mortality. CRP, PCT, IL-6 and LBP levels were significantly higher in patients with sepsis as compared to SIRS. With PCT levels in the first 24 hours after ICU admission <2 ng/mL, sepsis was virtually excluded (negative predictive value 97%). With PCT >10 ng/mL, sepsis with bacterial infection was very likely (positive predictive value 88%). PCT was best at discriminating between SIRS and sepsis with the highest area under the ROC curve (0.95, 95% CI 0.90–0.99). Discussion. This study showed that PCT is more useful than LBP, CRP and IL-6 in differentiating sepsis from SIRS.

[Antibiotic treatment of nosocomial pneumonia]

Nosocomial pneumonia is one of the most common infectious diseases acquired in hospital and is often caused by resistant pathogens. For treatment of nosocomial pneumonia an appropriate initial antibiotic therapy is essential and exact knowledge of the specific pathogen spectrum is essential for the correct choice of the empirically calculated antibiotics. In line with a critical reevaluation of the primary treatment, pathogen-specific de-escalation therapy, a diagnosis of possible pulmonary complications (e. g. pleural empyema) and the identification and appropriate rehabilitation measures of non-pulmonary infections are necessary. To attain the best possible outcome the respective therapy concept needs to be adjusted to the individual risk characteristics. Appropriate initial antibiotic therapy, duration of mechanical ventilation and comorbidities are the key factors for patient outcome. This approach helps to avoid the development of resistant pathogens and saves economic resources.

Procalcitonin as an early predictor of postoperative infectious complications in patients with acute traumatic spinal cord injury

STUDY DESIGN

Prospective, nonrandomized, observational cohort study.

OBJECTIVES

To analyze procalcitonin (PCT) level in acute traumatic spinal cord injury patients with and without postoperative infectious complications, and to determine whether PCT is a prognostic parameter of infectious complications in the early postoperative period compared with other inflammatory markers.

SETTING

Spine center of Chongqing, China; Trauma center of Chinese People's Liberation Army, China.

METHODS

A total of 339 consecutive patients with acute spinal cord injury undergone surgery were evaluated. All patients underwent measurement of leukocyte count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum PCT preoperatively and 24-48 h postoperatively.

RESULTS

In all, 26 (7.7%) of 339 participants experienced postoperative infectious complication. Patients with infection exhibited significantly higher PCT and CRP levels compared with noninfection (both P<0.01). Multivariate logistic regression analysis showed that PCT and CRP levels were independent predicators for postoperative infection. The area under the receiver operating characteristics curve of PCT and CRP were 0.82 (95% confidence intervals (CI) 0.74-0.91) and 0.68 (95%CI, 0.57-0.78), respectively. A PCT cutoff of 0.1 ng ml(-1) had a reasonable sensitivity of 92% to exclude an infection and antibiotics can be initially withheld. However, in patients with PCT level above 0.5 ng ml(-1), a rapid initiation of antibiotics may be warranted.

CONCLUSIONS

Serum PCT is a more reliable biologic marker for the early prediction of postoperative infectious complications in patients with acute traumatic spinal cord injury compared with CRP. PCT can early identify postoperative infections for establishing effective antibiotic therapy.

Biomarkers for pediatric sepsis and septic shock

Sepsis is a clinical syndrome defined by physiologic changes indicative of systemic inflammation, which are likely attributable to documented or suspected infection. Septic shock is the progression of those physiologic changes to the extent that delivery of oxygen and metabolic substrate to tissues is compromised. Biomarkers have the potential to diagnose, monitor, stratify and predict outcome in these syndromes. C-reactive protein is elevated in inflammatory and infectious conditions and has long been used as a biomarker indicating infection. Procalcitonin has more recently been shown to better distinguish infection from inflammation. Newer candidate biomarkers for infection include IL-18 and CD64. Lactate facilitates the diagnosis of septic shock and the monitoring of its progression. Multiple stratification biomarkers based on genome-wide expression profiling are under active investigation and present exciting future possibilities.