Surveillance Cultures in Healthcare-Associated Pneumonia

Sense or Nonsense?

Johannes B.J. Scholte; Walther N.K.A. van Mook; Catharina F.M. Linssen

Disclosures

Curr Opin Pulm Med. 2014;20(3):259-271. 

In This Article

Abstract and Introduction

Abstract

Purpose of review: This review explores the usefulness of surveillance cultures in healthcare-associated pneumonia (HCAP).

Recent findings: The definition of HCAP is controversial. Causative micro-organisms of HCAP resemble those found in hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Some types of surveillance cultures have proven useful in hospitalized patients. Whereas numerous studies have investigated the role of surveillance cultures in VAP, one may wonder whether surveillance culture implementation should belong in HCAP management guidelines.

Summary: Studies exploring the usefulness of obtaining surveillance cultures in VAP are numerous, but are mostly retrospective, observational and/or quasi-experimental in nature. Surveillance cultures may be useful for antibiotic guidance, but positive predictive value and specificity of surveillance cultures are low, obviously negatively impacting on cost effectiveness, especially in the large population at risk for HCAP. On the other hand, multidrug-resistance is increasing and surveillance cultures for methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci in ICU-admitted patients appeared useful and cost-effective. Furthermore, surveillance cultures for the presence of multidrug-resistant Gram-negative bacilli might be useful for antibiotic guidance. Currently, neither community-acquired pneumonia, HCAP, HAP nor VAP guidelines incorporate surveillance cultures. In the future, surveillance cultures in populations at risk for HCAP may be able to differentiate HCAP from other kinds of pneumonia and authorize its reason for existence.

Introduction

Healthcare-associated pneumonia (HCAP) is a relatively new phenomenon that develops outside the hospital, although in patients somehow related to the healthcare system. The population at risk for HCAP is inconsistently defined in literature, and consequently HCAP seems to occur in a rather heterogeneous population accounting for approximately one third of all pneumonia cases developing outside the hospital.[1] Yet, patients with HCAP are significantly older and suffer from more comorbidities.[2,3,4]

According to the most widely used international guideline for HCAP by the American Thoracic Society (ATS) and Infectious Diseases Society of America,[5] HCAP resembles hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), and consequently HCAP should be included in the spectrum of HAP and VAP and treated accordingly.

Indeed, large studies demonstrated that HCAP is frequently caused by similar pathogens as seen in HAP and VAP, especially methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa,[2,3,6–8] although other studies demonstrated more resemblance to community-acquired pneumonia (CAP) regarding causative micro-organisms.[4,9] A recent review of 24 studies confirms that HCAP patients, when compared with CAP patients, are more at risk for infections with MRSA, multidrug-resistant (MDR) Enterobacteriaceae or P. aeruginosa.[10] Furthermore, some studies demonstrate that HCAP increases the length of hospital stay and mortality rates, possibly related to comorbidities and age.[6,11] Undoubtedly, MDR is an increasing problem worldwide.[12] and the population at risk of HCAP is extending.

Notwithstanding the abovementioned commonalities and differences between CAP, HCAP, HAP and VAP, one might hypothesize that surveillance cultures can play a role in the diagnosis of HCAP. Indeed, surveillance cultures of endotracheal aspirate (ETA) are already frequently used to guide antibiotic therapy for VAP by selecting patients with MDR micro-organisms.

After providing a concise background regarding the use of surveillance cultures, this review aims to explore the potential usefulness of surveillance cultures in specific types of pneumonia and the extent to which surveillance cultures are included in current pneumonia guidelines, thereby attempting to provide recommendations regarding the role of surveillance cultures in future HCAP management.

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