Background
Hospital-acquired pneumonia (HAP) is defined as pneumonia that develops 48 hours or more after admission that was not present on admission; and ventilator-associated pneumonia (VAP) is pneumonia that develops 48 hours or more after endotracheal intubation.
HAP and VAP are common afflictions in hospitalized patients, accounting for nearly one-quarter of all hospital-acquired infections. They confer mortality rates of 24%-50%, increasing to nearly 75% if caused by resistant organisms.1,2 Given the high prevalence and significant mortality associated with these types of pneumonia, diagnosis and treatment are essential. Treatment must be balanced against potential unintended consequences of antibiotic use including Clostridium difficile infections and the promotion of resistant bacteria caused by poor antibiotic stewardship.
Given the frequency with which HAP and VAP occur, and the need for equipoise with antibiotic use, it is essential that all practicing clinicians have an evidence-based construct for the diagnosis and treatment of HAP and VAP.
Guideline updates
In 2016, the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) reconvened after 11 years to update their recommendations for the treatment of HAP and VAP.2 The decision to update their recommendations was based on the availability of new evidence regarding the diagnosis and treatment of these conditions.
Dr. Joseph Hippensteel
Included in this review are guideline updates on methods for diagnosis, initial antibiotic choice, pathogen-specific therapy, and duration of therapy. The guidelines also have recommendations for the role of inhaled antibiotics and pharmacokinetic optimization of antibiotic dosing, which will not be reviewed here.
Methods for Diagnosis: The use of semi-quantitative, noninvasive sampling of respiratory cultures is preferred for HAP and VAP, rather than empiric treatment or quantitative cultures (i.e., bronchoalveolar lavage, protected-specimen brush and blind bronchial sampling).
Initial antibiotic choice: For HAP and VAP, clinicians should include therapy targeting S. aureus, Pseudomonas aeruginosa, and other gram-negative bacilli. Therapy for methicillin-resistant S. aureus should be included if patients are at high risk for death (i.e., septic shock or ventilated patients) or if local drug-resistant prevalence is greater than 10%-20%. Similarly, two antipseudomonal antibiotics should be used only with empiric therapy if the patient is at high risk for mortality or local drug-resistant prevalence is greater than 10%.
Duration of therapy: HAP and VAP should be treated for 7 days with regimens that are tailored to culture data when available, assuming there has been appropriate clinical response. Procalcitonin may be paired with clinical judgment when considering antibiotic discontinuation.
Guideline analysis
There are several notable differences between the 2016 IDSA/ATS guidelines and the 2005 guidelines.3 The earlier guidelines recommended strong consideration of invasive respiratory cultures such as bronchoalveolar lavage or protected-specimen brush sampling for HAP/VAP. It is now recommended that only noninvasive cultures be performed in most clinical scenarios.
Dr. Jeffrey Sippel
Last, the updated guidelines recommend dual therapy for potential or documented Pseudomonas infection only for patients at high risk for mortality or in hospitals with a high prevalence of antibiotic resistance; previously, dual antipseudomonal therapy was recommended for all cases of HAP and VAP, based upon the risk of developing resistant strains with monotherapy.3
Since 2005, several organizations have released guidelines addressing the management of HAP and VAP.1,4,5,6 These are largely in keeping with the current version released by the IDSA/ATS. Across all guidelines, there is a focus on the importance of local antibiograms for appropriate and effective treatment, and the use of noninvasive culture data to guide therapy. Also, all groups recommend a short-course (7-8 days) of antibiotics for both HAP and VAP, assuming there has been an appropriate clinical response. The recent Canadian guidelines have one unique recommendation, which is to avoid the use of ceftazidime for suspected Pseudomonas pneumonia, based upon inferior outcomes when compared to alternative regimens.5
Takeaways
When considering the diagnosis of HAP and VAP, clinicians should be aware that the category of HCAP has been removed from current guidelines, and methods for microbiological diagnosis have been simplified.7 In addition, initial antibiotic selection should rely on institution-specific antibiograms and local resistance patterns when available. Recommended duration of therapy has been shortened, and should not include aminoglycosides.
Finally, antibiotic stewardship is the responsibility of each clinician and de-escalation of therapy for HAP and VAP should be guided by available respiratory cultures.
Dr. Hippensteel is a pulmonologist in Aurora, Colo. Dr. Sippel is visiting associate professor of clinical practice, medicine-pulmonary sciences & critical care at the University of Colorado School of Medicine.
References
1. Masterton R, Galloway A, French G, Street M, Armstrong J, Brown E, Cleverley J, Dilworth P, Fry C, Gascoigne A. Guidelines for the management of hospital-acquired pneumonia in the UK: report of the working party on hospital-acquired pneumonia of the British Society for Antimicrobial Chemotherapy. J Antimicrob Chemother. 2008;62(1):5-34.
2. Kalil AC, Metersky ML, Klompas M, Muscedere J, Sweeney DA, Palmer LB, Napolitano LM, O’grady NP, Bartlett JG, Carratalà J. 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:ciw353.
3. Society AT, America IDSo. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med. 2005;171(4):388-416.
4. Dalhoff K, Abele-Horn M, Andreas S, Bauer T, von Baum H, Deja M, Ewig S, Gastmeier P, Gatermann S, Gerlach H. Epidemiology, diagnosis, and treatment of adult patients with nosocomial pneumonia. S-3 Guideline of the German Society for Anaesthesiology and Intensive Care Medicine, the German Society for Infectious Diseases, the German Society for Hygiene and Microbiology, the German Respiratory Society and the Paul-Ehrlich-Society for Chemotherapy. Pneumologie (Stuttgart, Germany). 2012;66(12):707-65.
5. Rotstein C, Evans G, Born A, Grossman R, Light RB, Magder S, McTaggart B, Weiss K, Zhanel GG. Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults. Canadian Journal of Infectious Diseases and Medical Microbiology. 2008;19(1):19-53.
6. Coffin SE, Klompas M, Classen D, Arias KM, Podgorny K, Anderson DJ, Burstin H, Calfee DP, Dubberke ER, Fraser V. Strategies to prevent ventilator-associated pneumonia in acute care hospitals. Infect Control Hosp Epidemiol. 2008;29(S1):S31-S40.
7. Tablan OC, Anderson LJ, Besser R, Bridges C, Hajjeh R. Guidelines for preventing healthcare-associated pneumonia, 2003. MMWR. 2004;53(RR-3):1-36.
