Ventilator-Associated Pneumonia: Diagnostic Test Stewardship and Relevance of Culturing Practices
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Purpose of Review
Ventilator-associated pneumonia (VAP) is one of the most common infections in the ICU. Prompt diagnosis is vital as mortality increases with delayed antibiotic therapy. However, accurate diagnosis is challenging due to non-specific clinical features in a complicated patient cohort. Microbiological culture data remains a crucial aspect in confirming diagnosis.
Literature data comparing the benefit of invasive respiratory sampling to non-invasive is inconclusive. Differences in culturing practices translate in overidentification of organisms of unclear significance. Positive culture data in a low pre-test probability does not differentiate between true infection and colonization resulting in overtreatment. Furthermore, there are also opportunities for modifying the reporting of respiratory tract cultures that can better guide antimicrobial therapy.
Under the umbrella of antimicrobial stewardship, diagnostic stewardship can be incorporated to create a systematic approach that would target culturing practices to match the right pre-test probability. Ideal outcome will be targeting cultures to the right patient population and minimizing unnecessary treatment.
KeywordsVentilator-associated pneumonia Diagnostic stewardship Antimicrobial stewardship Selective culture reporting Invasive respiratory culturing Endotracheal aspirate
Compliance with Ethical Standards
Conflict of Interest
Dr. Kenaa declares that she has nothing to disclose.
Dr. Richert declares that she has nothing to disclose.
Dr. Claeys reports personal fees from Luminex Corporation, other from BioFire Diagnostics, from GenMark Diagnostics, outside the submitted work.
Ms. Shipper declares that she nothing to disclose.
Dr. O’Hara declares that she has nothing to disclose.
Dr. Sullivan declares that he has nothing to disclose.
Dr. Schrank declares that he has nothing to disclose.
Dr. Morgan reports grants from CDC, NIH, AHRQ, grants from VA HSRD, other from IDSA and SHEA for expenses to organize or present at national meetings, other from Springer Nature Inc., outside the submitted work.
Dr. Shanholtz declares that he has nothing to disclose.
Dr. Leekha reports grants from CDC and AHRQ, outside the submitted work.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
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- 4.Kalil AC, Metersky ML, Klompas M, Muscedere J, Sweeney DA, Palmer LB, et al. Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clin Infect Dis. 2016 Sep 1;63(5):e61–111.PubMedPubMedCentralCrossRefGoogle Scholar
- 5.Dudeck MA, Weiner LM, Allen-Bridson K, Malpiedi PJ, Peterson KD, Pollock DA, et al. National Healthcare Safety Network (NHSN) report, data summary for 2012, Device-associated module Am J Infect Control 2013;Google Scholar
- 7.• Morgan DJ, Malani P, Diekema DJ. Diagnostic stewardship - leveraging the laboratory to improve antimicrobial use. JAMA - Journal of the American Medical Association. 2017; This editorial discusses the importance of engaging the laboratory to ensure culture testing in the right pre-test probability. It also highlights the role of collection, processing, and reporting of the sample play a role in appropriate treatment of infections. Google Scholar
- 9.Baur D, Gladstone BP, Burkert F, Carrara E, Foschi F, Döbele S, et al. Effect of antibiotic stewardship on the incidence of infection and colonisation with antibiotic-resistant bacteria and Clostridium difficile infection: a systematic review and meta-analysis. Lancet Infect Dis. 2017;17(9):990–1001.PubMedCrossRefGoogle Scholar
- 11.Bashir A, Gray J, Bashir S, Ahmed R, Theodosiou E. Critical points in the pathway of antibiotic prescribing in a children’s hospital: the Antibiotic Mapping of Prescribing (ABMAP) study. J Hosp Infect [Internet]. 2018;44:1–6.Google Scholar
- 12.Barlam TF, Cosgrove SE, Abbo LM, Macdougall C, Schuetz AN, Septimus EJ, et al. Executive summary: implementing an antibiotic stewardship program: guidelines by the infectious diseases society of America and the society for healthcare epidemiology of America. Clin Infect Dis. 2016.Google Scholar
- 15.Chao WC, Chang WL, Wu CL, Chan MC. Using objective fluid balance data to identify pulmonary edema in subjects with ventilator-associated events. Respir Care. 2018 Aug 7;Google Scholar
- 19.Solé Violán J, Fernández JA, Benítez AB, Cardeñosa Cendrero JA, Rodríguez de C. Impact of quantitative invasive diagnostic techniques in the management and outcome of mechanically ventilated patients with suspected pneumonia. Crit Care Med [Internet] 2000;28(8):2737–2741.PubMedCrossRefGoogle Scholar
- 22.Berton DC, Kalil AC, Teixeira PJZ. Quantitative versus qualitative cultures of respiratory secretions for clinical outcomes in patients with ventilator-associated pneumonia. Cochrane Database of Systematic Reviews. 2014.Google Scholar
- 23.•• Lascarrou JB, Lissonde F, Le Thuaut A, Bachoumas K, Colin G, Henry Lagarrigue M, et al. Antibiotic therapy in comatose mechanically ventilated patients following aspiration: differentiating pneumonia from pneumonitis. Crit Care Med [Internet]. 2017;45(8):1268–1275. In this prospective observational study, investigators highlight the challenge in clinically differentiating bacterial aspiration pneumonia from non-bacterial aspiration pneumonitis. With invasive respiratory sampling, it is possible to get culture data that can guide in early discontinuation of empiric antibiotics. PubMedCrossRefGoogle Scholar
- 24.Frota OP, Ferreira AM, Barcelos L, da Watanabe SE, Carvalho NCP, Rigotti MA. Collection of tracheal aspirate: safety and microbiological concordance between two techniques TT - Colheita de aspirado traqueal: segurança e concordância microbiológica entre duas técnicas TT - Recolección de aspirado traqueal: seguridad y concordanci. Rev da Esc Enferm da USP [Internet]. 2014;48(4):618–24.CrossRefGoogle Scholar
- 28.Bouza E, Muñoz P, Burillo A. Role of the clinical microbiology laboratory in antimicrobial stewardship. Medical Clinics of North America. 2018.Google Scholar
- 30.•• Shokouhi S, Darazam IA, Sadeghi M, Gachkar L, Dolatshahi S. Diagnostic yield of a direct quantitative smear of lower respiratory tract secretions in patients with suspected pneumonia compared with a semi-quantitative culture. Tanaffos. 2017;16(1):9–12. In this prospective study, investigators evaluated how Direct Quantitative Smear with proper staining maybe an easy, cost-effective, and rapid method. They compared respiratory sample from BAL and endotracheal aspirate to identify a 35 microorganisms in10 HPF of microscopy was the ideal cutoff. Though still novel and difficult to apply for different microorganisms and in different laboratory settings, this approach could be investigated further as a way to quickly identify the absence of pathogenic organisms and discontinue antibiotics earlier. Google Scholar
- 31.• Yoshimura J, Kinoshita T, Yamakawa K, Matsushima A, Nakamoto N, Hamasaki T, et al. Impact of Gram stain results on initial treatment selection in patients with ventilator-associated pneumonia: a retrospective analysis of two treatment algorithms. Crit Care [Internet]. 2017;21(1) In this study, investigators wanted to evaluate if bedside Gram stain of endotracheal aspirates could be used to determine appropriate initial antimicrobial therapy for VAP as compared with ATS/IDSA guidelines algorithmic approach. Google Scholar
- 33.Rhee C. Using procalcitonin to guide antibiotic therapy. Open Forum Infect Dis. 2017;4(1):1–10.Google Scholar
- 35.•• Musgrove MA, Tibbetts R, Peters M, Samuel L, Davis SL, Kendall RE, et al. Microbiology comment nudge improves pneumonia prescribing. Open Forum Infect Dis. 2018;5(7):1–5 In this single pre and post quasi experimental study, investigators enrolled two hundred and ten patients who were treated with anti-MRSA and anti-pseudomonal antibiotics for respiratory infections. Reporting of cultures for patients without dominant organisms were labeled as “commensal respiratory flora only: no S.aureus/MRSA or P.aeroginosa.” In the post intervention group, there was a 5.5 increased odds of antibiotic de-escalation. CrossRefGoogle Scholar
- 38.• Naik AD, Skelton F, Amspoker AB, Glasgow RA, Trautner BW. A fast and frugal algorithm to strengthen diagnosis and treatment decisions for catheter-associated bacteriuria. PLoS One. 2017;12(3) Improving the diagnostic and treatment accuracy for CAUTI by implementing a fast and frugal algorithm results in the reduction of overtreatment of asymptomatic bacteruria.PubMedPubMedCentralCrossRefGoogle Scholar