Role of biomarkers in the management of antibiotic therapy: An expert panel review II: Clinical use of biomarkers for initiation or discontinuation of antibiotic therapy

Annals of Intensive Care

Volumn 3, Issue 1, 2013, Pages 1-17

  Quenot, Jean Pierre ^a,b   Luyt, Charles Edouard ^c   Roche, Nicolas ^d   Chalumeau, Martin ^b,e   Charles, Pierre Emmanuel ^a   Claessens, Yann Eric ^f   Lasocki, Sigismond ^g   Bedos, Jean Pierre ^h   Péan, Yves ⁱ   Philippart, François ^j   Ruiz, Stéphanie ^k   Gras Leguen, Christele ^l   Dupuy, Anne Marie ^m   Pugin, Jérôme ⁿ   Stahl, Jean Paul ^o   Misset, Benoit ^j   Gauzit, Rémy ^p   Brun Buisson, Christian ^q,r  

^a UNIVERSITÉ DE BOURGOGNE   (France)

^b INSERM   (France)

^c ASSISTANCE PUBLIQUE HÔPITAUX DE PARIS   (France)

^d UNIVERSITÉ PARIS DESCARTES   (France)

^e HÔPITAL NECKER ENFANTS MALADES   (France)

^f CENTRE HOSPITALIER PRINCESSE GRACE   (Monaco)

^g ANGERS UNIVERSITY HOSPITAL   (France)

^h CENTRE HOSPITALIER DE VERSAILLES   (France)

ⁱ INSTITUT MUTUALISTE MONTSOURIS   (France)

^j SAINT JOSEPH HOSPITAL   (France)

^k CHU RANGUEIL   (France)

^l Hopital Mere Enfant CHU de Nantes   (France)

^m LAPEYRONIE HOSPITAL   (France)

ⁿ GENEVA UNIVERSITY HOSPITALS   (Switzerland)

^o UNIV GRENOBLE ALPES   (France)

^p HÔTEL DIEU   (France)

^q HENRI MONDOR HOSPITAL   (France)

^r INSTITUT PASTEUR   (France)

more..

Author keywords

Biomarkers; C reactive protein; Emergency medicine; Infection; Meningitis; Pancreatitis; Pneumonia; Procalcitonin; Sepsis

Indexed keywords

ANTIBIOTIC AGENT; BIOLOGICAL MARKER; C REACTIVE PROTEIN; INTERLEUKIN 6; INTERLEUKIN 8; PROCALCITONIN; TRIGGERING RECEPTOR EXPRESSED ON MYELOID CELLS 1; TUMOR NECROSIS FACTOR ALPHA;

ABDOMINAL ABSCESS; ABDOMINAL DISCOMFORT; ACUTE PANCREATITIS; ALGORITHM; ANTIBIOTIC THERAPY; BACTERIAL ENDOCARDITIS; BACTERIAL MENINGITIS; BONE MARROW TRANSPLANTATION; BRONCHITIS; CEREBROSPINAL FLUID; CHRONIC OBSTRUCTIVE LUNG DISEASE; CLINICAL DECISION MAKING; CLINICAL EVALUATION; COMMUNICABLE DISEASE; DECISION MAKING; DIAGNOSTIC VALUE; DIFFERENTIAL DIAGNOSIS; DISEASE SEVERITY; EMERGENCY MEDICINE; EMERGENCY WARD; FALSE NEGATIVE RESULT; FINE NEEDLE ASPIRATION BIOPSY; FOLLOW UP; HOSPITAL INFECTION; HOSPITAL PATIENT; HUMAN; IMMUNOCOMPROMISED PATIENT; INFECTIOUS ARTHRITIS; INTENSIVE CARE UNIT; LABORATORY DIAGNOSIS; LOWER RESPIRATORY TRACT INFECTION; MEDIASTINITIS; MENINGITIS; META ANALYSIS (TOPIC); MULTICENTER STUDY (TOPIC); MULTIPLE ORGAN FAILURE; OBSERVATIONAL STUDY; OUTPATIENT CARE; PANCREAS NECROSIS; PRESCRIPTION; PRIORITY JOURNAL; PROGNOSIS; PROSPECTIVE STUDY; PROTEIN BLOOD LEVEL; PROTEIN CEREBROSPINAL FLUID LEVEL; RANDOMIZED CONTROLLED TRIAL (TOPIC); REVIEW; RISK REDUCTION; SEIZURE; SENSITIVITY AND SPECIFICITY; SEPSIS; SYSTEMATIC REVIEW (TOPIC); TREATMENT DURATION; UPPER RESPIRATORY TRACT INFECTION; VIRUS ETIOLOGY; VIRUS MENINGITIS; WATCHFUL WAITING;

EID: 84881262928     PISSN: None     EISSN: 21105820     Source Type: Journal    
DOI: 10.1186/2110-5820-3-21     Document Type: Review

References (75)

1. Mofidi R, Suttie SA, Patil PV, Ogston S, Parks RW: The value of procalcitonin at predicting the severity of acute pancreatitis and development of infected pancreatic necrosis: systematic review. Surgery 2009, 146:72-81.
2. Rau B, Steinbach G, Baumgart K, Gansauge F, Grunert A, Beger HG: The clinical value of procalcitonin in the prediction of infected necrosis in acute pancreatitis. Intensive Care Med 2000, 26(Suppl 2):S159-S164.
3. Morgenthaler NG, Struck J, Christ-Crain M, Bergmann A, Muller B: Pro-atrial natriuretic peptide is a prognostic marker in sepsis, similar to the APACHE II score: an observational study. Crit Care 2005, 9:R37-R45.
4. Rau B, Steinbach G, Gansauge F, Mayer JM, Grunert A, Beger HG: The potential role of procalcitonin and interleukin 8 in the prediction of infected necrosis in acute pancreatitis. Gut 1997, 41:832-840.
5. Riche FC, Cholley BP, Laisne MJ, Vicaut E, Panis YH, Lajeunie EJ, Boudiaf M, Valleur PD: Inflammatory cytokines, C reactive protein, and procalcitonin as early predictors of necrosis infection in acute necrotizing pancreatitis. Surgery 2003, 133:257-262.
6. Purkayastha S, Chow A, Athanasiou T, Cambaroudis A, Panesar S, Kinross J, Tekkis P, Darzi A: Does serum procalcitonin have a role in evaluating the severity of acute pancreatitis? A question revisited. World J Surg 2006, 30:1713-1721.
7. Lu Z, Liu Y, Dong YH, Zhan XB, Du YQ, Gao J, Gong YF, Li ZS: Soluble triggering receptor expressed on myeloid cells in severe acute pancreatitis: a biological marker of infected necrosis. Intensive Care Med 2012, 38:69-75.
8. Olah A, Belagyi T, Issekutz A, Makay R, Zaborszky A: Value of procalcitonin quick test in the differentiation between sterile and infected forms of acute pancreatitis. Hepatogastroenterology 2005, 52:243-245.
9. Mandi Y, Farkas G, Takacs T, Boda K, Lonovics J: Diagnostic relevance of procalcitonin, IL-6, and sICAM-1 in the prediction of infected necrosis in acute pancreatitis. Int J Pancreatol 2000, 28:41-49.
10. Muller CA, Uhl W, Printzen G, Gloor B, Bischofberger H, Tcholakov O, Buchler MW: Role of procalcitonin and granulocyte colony stimulating factor in the early prediction of infected necrosis in severe acute pancreatitis. Gut 2000, 46:233-238.
11. Evans AT, Husain S, Durairaj L, Sadowski LS, Charles-Damte M, Wang Y: Azithromycin for acute bronchitis: a randomised, double-blind, controlled trial. Lancet 2002, 359:1648-1654.
12. Poses RM, Cebul RD, Wigton RS: You can lead a horse to water-improving physicians' knowledge of probabilities may not affect their decisions. Med Decis Making 1995, 15:65-75.
13. Sabuncu E, David J, Bernede-Bauduin C, Pepin S, Leroy M, Boelle PY, Watier L, Guillemot D: Significant reduction of antibiotic use in the community after a nationwide campaign in France, 2002-2007. PLoS Med 2009, 6:e1000084.
14. Briel M, Christ-Crain M, Young J, Schuetz P, Huber P, Periat P, Bucher HC, Muller B: Procalcitonin-guided antibiotic use versus a standard approach for acute respiratory tract infections in primary care: study protocol for a randomised controlled trial and baseline characteristics of participating general practitioners [ISRCTN73182671]. BMC Fam Pract 2005, 6:34.
15. Briel M, Schuetz P, Mueller B, Young J, Schild U, Nusbaumer C, Periat P, Bucher HC, Christ-Crain M: Procalcitonin-guided antibiotic use vs a standard approach for acute respiratory tract infections in primary care. Arch Intern Med 2008, 168:2000-2007. discussion 2007-2008.
16. Burkhardt O, Ewig S, Haagen U, Giersdorf S, Hartmann O, Wegscheider K, Hummers-Pradier E, Welte T: Procalcitonin guidance and reduction of antibiotic use in acute respiratory tract infection. Eur Respir J 2010, 36:601-607.
17. Christ-Crain M, Jaccard-Stolz D, Bingisser R, Gencay MM, Huber PR, Tamm M, Muller B: Effect of procalcitonin-guided treatment on antibiotic use and outcome in lower respiratory tract infections: cluster-randomised, single-blinded intervention trial. Lancet 2004, 363:600-607.
18. Christ-Crain M, Stolz D, Bingisser R, Muller C, Miedinger D, Huber PR, Zimmerli W, Harbarth S, Tamm M, Muller B: Procalcitonin guidance of antibiotic therapy in community-acquired pneumonia: a randomized trial. Am J Respir Crit Care Med 2006, 174:84-93.
19. Kristoffersen KB, Sogaard OS, Wejse C, Black FT, Greve T, Tarp B, Storgaard M, Sodemann M: Antibiotic treatment interruption of suspected lower respiratory tract infections based on a single procalcitonin measurement at hospital admission-a randomized trial. Clin Microbiol Infect 2009, 15:481-487.
20. Stolz D, Christ-Crain M, Bingisser R, Leuppi J, Miedinger D, Muller C, Huber P, Muller B, Tamm M: Antibiotic treatment of exacerbations of COPD: a randomized, controlled trial comparing procalcitonin-guidance with standard therapy. Chest 2007, 131:9-19.
21. Kumar A, Roberts D, Wood KE, Light B, Parrillo JE, Sharma S, Suppes R, Feinstein D, Zanotti S, Taiberg L, et al: Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med 2006, 34:1589-1596.
22. Long W, Deng X, Zhang Y, Lu G, Xie J, Tang J: Procalcitonin guidance for reduction of antibiotic use in low-risk outpatients with community-acquired pneumonia. Respirology 2011, 16:819-824.
23. Long W, Deng XQ, Tang JG, Xie J, Zhang YC, Zhang Y, Gao YY, Lu G: The value of serum procalcitonin in treatment of community acquired pneumonia in outpatient. Zhonghua Nei Ke Za Zhi 2009, 48:216-219.
24. Cals JW, Butler CC, Hopstaken RM, Hood K, Dinant GJ: Effect of point of care testing for C reactive protein and training in communication skills on antibiotic use in lower respiratory tract infections: cluster randomised trial. BMJ (Clinical research ed 2009:b1374.
25. Schuetz P, Christ-Crain M, Thomann R, Falconnier C, Wolbers M, Widmer I, Neidert S, Fricker T, Blum C, Schild U, et al: Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial. JAMA 2009, 302:1059-1066.
26. Muller B, Becker KL, Schachinger H, Rickenbacher PR, Huber PR, Zimmerli W, Ritz R: Calcitonin precursors are reliable markers of sepsis in a medical intensive care unit. Crit Care Med 2000, 28:977-983.
27. Albrich WC, Dusemund F, Bucher B, Meyer S, Thomann R, Kuhn F, Bassetti S, Sprenger M, Bachli E, Sigrist T, et al: Effectiveness and safety of procalcitonin-guided antibiotic therapy in lower respiratory tract infections in real life: an international, multicenter poststudy survey (ProREAL). Arch Intern Med 2012, 172:715-722.
28. Van Der Meer V, Neven AK, van den Broek PJ, Assendelft WJ: Diagnostic value of C reactive protein in infections of the lower respiratory tract: systematic review. BMJ (Clinical research ed 2005, 331:26.
29. Schuetz P, Chiappa V, Briel M, Greenwald JL: Procalcitonin algorithms for antibiotic therapy decisions: a systematic review of randomized controlled trials and recommendations for clinical algorithms. Arch Intern Med 2011, 171:1322-1331.
30. Chenevier-Gobeaux C, Trabattoni E, Elfassy Y, Picard C, Guerin S, Borderie D, Claessens YE: Decisional procalcitonin thresholds are not adapted to elderly patients admitted to the emergency room. Biomarkers 2012, 17:477-481.
31. Schuetz P, Muller B, Christ-Crain M, Stolz D, Tamm M, Bouadma L, Luyt CE, Wolff M, Chastre J, Tubach F, et al: Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections. Cochrane database of systematic reviews (Online) 2012, 9:CD007498.
32. Schuetz P, Briel M, Christ-Crain M, Stolz D, Bouadma L, Wolff M, Luyt CE, Chastre J, Tubach F, Kristoffersen KB, et al: Procalcitonin to guide initiation and duration of antibiotic treatment in acute respiratory infections: an individual patient data meta-analysis. Clin Infect Dis 2012, 55:651-662.
33. Bouadma L, Luyt CE, Tubach F, Cracco C, Alvarez A, Schwebel C, Schortgen F, Lasocki S, Veber B, Dehoux M, et al: Use of procalcitonin to reduce patients' exposure to antibiotics in intensive care units (PRORATA trial): a multicentre randomised controlled trial. Lancet 2010, 375:463-474.
34. Layios N, Lambermont B, Canivet JL, Morimont P, Preiser JC, Garweg C, Ledoux D, Frippiat F, Piret S, Giot JB, et al: Procalcitonin usefulness for the initiation of antibiotic treatment in intensive care unit patients. Crit Care Med 2012, 40:2304-2309.
35. Nobre V, Harbarth S, Graf JD, Rohner P, Pugin J: Use of procalcitonin to shorten antibiotic treatment duration in septic patients: a randomized trial. Am J Respir Crit Care Med 2008, 177:498-505.
36. Charles PE, Kus E, Aho S, Prin S, Doise JM, Olsson NO, Blettery B, Quenot JP: Serum procalcitonin for the early recognition of nosocomial infection in the critically ill patients: a preliminary report. BMC Infect Dis 2009, 9:49.
37. Nigrovic LE, Kuppermann N, Macias CG, Cannavino CR, Moro-Sutherland DM, Schremmer RD, Schwab SH, Agrawal D, Mansour KM, Bennett JE, et al: Clinical prediction rule for identifying children with cerebrospinal fluid pleocytosis at very low risk of bacterial meningitis. JAMA 2007, 297:52-60.
38. Dubos F, Lamotte B, Bibi-Triki F, Moulin F, Raymond J, Gendrel D, Breart G, Chalumeau M: Clinical decision rules to distinguish between bacterial and aseptic meningitis. Arch Dis Child 2006, 91:647-650.
39. Saez-Llorens X, McCracken GH Jr: Bacterial meningitis in children. Lancet 2003, 361:2139-2148.
40. Tunkel AR, Hartman BJ, Kaplan SL, Kaufman BA, Roos KL, Scheld WM, Whitley RJ: Practice guidelines for the management of bacterial meningitis. Clin Infect Dis 2004, 39:1267-1284.
41. Khetsuriani N, Quiroz ES, Holman RC, Anderson LJ: Viral meningitis-associated hospitalizations in the United States, 1988-1999. Neuroepidemiology 2003, 22:345-352.
42. Gendrel D, Raymond J, Assicot M, Moulin F, Iniguez JL, Lebon P, Bohuon C: Measurement of procalcitonin levels in children with bacterial or viral meningitis. Clin Infect Dis 1997, 24:1240-1242.
43. Marc E, Menager C, Moulin F, Stos B, Chalumeau M, Guerin S, Lebon P, Brunet F, Raymond J, Gendrel D: Procalcitonin and viral meningitis: reduction of unnecessary antibiotics by measurement during an outbreak. Arch Pediatr 2002, 9:358-364.
44. Dubos F, Moulin F, Gajdos V, De Suremain N, Biscardi S, Lebon P, Raymond J, Breart G, Gendrel D, Chalumeau M: Serum procalcitonin and other biologic markers to distinguish between bacterial and aseptic meningitis. J Pediatr 2006, 149:72-76.
45. Dubos F, Korczowski B, Aygun DA, Martinot A, Prat C, Galetto-Lacour A, Casado-Flores J, Taskin E, Leclerc F, Rodrigo C, et al: Serum procalcitonin level and other biological markers to distinguish between bacterial and aseptic meningitis in children: a European multicenter case cohort study. Arch Pediatr Adolesc Med 2008, 162:1157-1163.
46. Nigrovic LE, Kuppermann N, Malley R: Development and validation of a multivariable predictive model to distinguish bacterial from aseptic meningitis in children in the post-Haemophilus influenzae era. Pediatrics 2002, 110:712-719.
47. Hoen B, Viel JF, Paquot C, Gerard A, Canton P: Multivariate approach to differential diagnosis of acute meningitis. Eur J Clin Microbiol Infect Dis 1995, 14:267-274.
48. Freedman SB, Marrocco A, Pirie J, Dick PT: Predictors of bacterial meningitis in the era after Haemophilus influenzae. Arch Pediatr Adolesc Med 2001, 155:1301-1306.
49. Oostenbrink R, Moons KG, Twijnstra MJ, Grobbee DE, Moll HA: Children with meningeal signs: predicting who needs empiric antibiotic treatment. Arch Pediatr Adolesc Med 2002, 156:1189-1194.
50. Bonsu BK, Harper MB: Differentiating acute bacterial meningitis from acute viral meningitis among children with cerebrospinal fluid pleocytosis: a multivariable regression model. Pediatr Infect Dis J 2004, 23:511-517.
51. Bingen E, Levy C, de la Rocque F, Boucherat M, Varon E, Alonso JM, Dabernat H, Reinert P, Aujard Y, Cohen R: Bacterial meningitis in children: a French prospective study. Clin Infect Dis 2005, 41:1059-1063.
52. Dubos F, De la Rocque F, Levy C, Bingen E, Aujard Y, Cohen R, Breart G, Gendrel D, Chalumeau M: Sensitivity of the bacterial meningitis score in 889 children with bacterial meningitis. J Pediatr 2008, 152:378-382.
53. Nigrovic LE, Malley R, Kuppermann N: Meta-analysis of bacterial meningitis score validation studies. Arch Dis Child 2012, 97:799-805.
54. Dubos F, Moulin F, Raymond J, Gendrel D, Breart G, Chalumeau M: Distinction between bacterial and aseptic meningitis in children: refinement of a clinical decision rule. Arch Pediatr 2007, 14:434-438.
55. Dubos F, Korczowski B, Aygun DA, Martinot A, Prat C, Galetto-Lacour A, Casado-Flores J, Taskin E, Leclerc F, Rodrigo C, et al: Distinguishing Quenotetal. AnnalsofIntensive Care 2013, 3:21 between bacterial and aseptic meningitis in children: European comparison of two clinical decision rules. Arch Dis Child 2010, 95:963-967.
56. Société de Pathologie Infectieuse de Langue Française (SPILF): Practice guidelines for acute bacterial meningitidis (except newborn and nosocomial meningitis). Med Mal Infect 2009, 39:356-367.
57. Baty V, Viel JF, Schuhmacher H, Jaeger F, Canton P, Hoen B: Prospective validation of a diagnosis model as an aid to therapeutic decision-making in acute meningitis. Eur J Clin Microbiol Infect Dis 2000, 19:422-426.
58. Knudsen TB, Larsen K, Kristiansen TB, Moller HJ, Tvede M, Eugen-Olsen J, Kronborg G: Diagnostic value of soluble CD163 serum levels in patients suspected of meningitis: comparison with CRP and procalcitonin. Scand J Infect Dis 2007, 39:542-553.
59. Ray P, Badarou-Acossi G, Viallon A, Boutoille D, Arthaud M, Trystram D, Riou B: Accuracy of the cerebrospinal fluid results to differentiate bacterial from non bacterial meningitis, in case of negative gram-stained smear. Am J Emerg Med 2007, 25:179-184.
60. Schwarz S, Bertram M, Schwab S, Andrassy K, Hacke W: Serum procalcitonin levels in bacterial and abacterial meningitis. Crit Care Med 2000, 28:1828-1832.
61. Viallon A, Desseigne N, Marjollet O, Birynczyk A, Belin M, Guyomarch S, Borg J, Pozetto B, Bertrand JC, Zeni F: Meningitis in adult patients with a negative direct cerebrospinal fluid examination: value of cytochemical markers for differential diagnosis. Crit Care 2011, 15:R136.
62. Gerdes LU, Jorgensen PE, Nexo E, Wang P: C-reactive protein and bacterial meningitis: a meta-analysis. Scand J Clin Lab Invest 1998, 58:383-393.
63. Wacker C, Prkno A, Brunkhorst FM, Schlattmann P: Procalcitonin as a diagnostic marker for sepsis: a systematic review and meta-analysis. Lancet Infect Dis 2013, 13:426-435.
64. Theodorou VP, Papaioannou VE, Tripsianis GA, Panopoulou MK, Christophoridis EK, Kouliatsis GA, Gioka TM, Maltezos ES, Ktenidou-Kartali SI, Pneumatikos IA: Procalcitonin and procalcitonin kinetics for diagnosis and prognosis of intravascular catheter-related bloodstream infections in selected critically ill patients: a prospective observational study. BMC Infect Dis 2012, 12:247.
65. Jensen JU, Hein L, Lundgren B, Bestle MH, Mohr TT, Andersen MH, Thornberg KJ, Loken J, Steensen M, Fox Z, et al: Procalcitonin-guided interventions against infections to increase early appropriate antibiotics and improve survival in the intensive care unit: a randomized trial. Crit Care Med 2011, 39:2048-2058.
66. Cals JW, Hopstaken RM, Butler CC, Hood K, Severens JL, Dinant GJ: Improving management of patients with acute cough by C-reactive protein point of care testing and communication training (IMPAC3T): study protocol of a cluster randomised controlled trial. BMC Fam Pract 2007, 8:15.
67. Diederichsen HZ, Skamling M, Diederichsen A, Grinsted P, Antonsen S, Petersen PH, Munck AP, Kragstrup J: Randomised controlled trial of CRP rapid test as a guide to treatment of respiratory infections in general practice. Scand J Prim Health Care 2000, 18:39-43.
68. Gonzales R, Aagaard EM, Camargo CA Jr, Ma OJ, Plautz M, Maselli JH, McCulloch CE, Levin SK, Metlay JP: C-reactive protein testing does not decrease antibiotic use for acute cough illness when compared to a clinical algorithm. J Emerg Med 2011, 41:1-7.
69. Stolz D, Smyrnios N, Eggimann P, Pargger H, Thakkar N, Siegemund M, Marsch S, Azzola A, Rakic J, Mueller B, Tamm M: Procalcitonin for reduced antibiotic exposure in ventilator-associated pneumonia: a randomised study. Eur Respir J 2009, 34:1364-1375.
70. Hochreiter M, Kohler T, Schweiger AM, Keck FS, Bein B, Von Spiegel T, Schroeder S: Procalcitonin to guide duration of antibiotic therapy in intensive care patients: a randomized prospective controlled trial. Crit Care 2009, 13:R83.
71. Kopterides P, Siempos II, Tsangaris I, Tsantes A, Armaganidis A: Procalcitonin-guided algorithms of antibiotic therapy in the intensive care unit: a systematic review and meta-analysis of randomized controlled trials. Crit Care Med 2010, 38:2229-2241.
72. Schuetz P, Christ-Crain M, Muller B: Procalcitonin and other biomarkers to improve assessment and antibiotic stewardship in infections-hope for hype? Swiss Med Wkly 2009, 139:318-326.
73. Schroeder S, Hochreiter M, Koehler T, Schweiger AM, Bein B, Keck FS, Von Spiegel T: Procalcitonin (PCT)-guided algorithm reduces length of antibiotic treatment in surgical intensive care patients with severe sepsis: results of a prospective randomized study. Langenbecks Arch Surg 2009, 394:221-226.
74. Tang BM, Eslick GD, Craig JC, McLean AS: Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis. Lancet Infect Dis 2007, 7:210-217.
75. Li H, Luo YF, Blackwell TS, Xie CM: Meta-analysis and systematic review of procalcitonin-guided therapy in respiratory tract infections. Antimicrob Agents Chemother 2011, 55:5900-5906.