Initial Microbiologic Studies Did Not Affect Outcome in Adults Hospitalized with Community-Acquired Pneumonia

Abstract

Microbiologic studies (MBSs) fail to identify a specific pathogen in more than 50% of patients with community-acquired pneumonia (CAP). The 1993 American Thoracic Society guideline (ATS-GL) for the management of CAP advised selecting initial antibiotic regimens based on severity of illness and comorbidities. Our study evaluated the role of initial MBS in adult patients hospitalized with CAP and treated according to the ATS-GL. In 184 patients hospitalized at our facility for CAP in 1996, and treated according to the ATS-GL, 25 (14%) failed to respond to initial antibiotic regimens. In these nonresponders, there was no difference in mortality between those in whom antibiotics were changed empirically, and those with MBS-guided changes. We conclude that initial MBS may not be warranted in many adult patients admitted for CAP. Exceptions include patients with conditions that predispose to less common, more resistant pathogens.

Guidelines for the management of adult lower respiratory tract infections

“…No study has shown that initial microbiological studies affect outcome [59]. Nevertheless, many clinicians feel that microbial investigation may be of help in guiding treatment, particularly in the more severely ill patients.…”

Improving the use of sputum cultures in lower respiratory tract infection

“…15 In general our findings are supportive of literature showing that sputum samples have little overall impact upon practical management of patients. [2][3][4]16,17 Prior to our intervention approximately 13% of sputum samples (45/347) appeared to lead to a change in management, but half of these samples were 'inappropriate'. Even fewer samples (around 3%, 4/133) directly altered prescribing after the intervention.…”

“…Evidence suggests that sputum sampling has low sensitivity, specificity and impact on treatment decisions. [1][2][3][4] Ideally antibiotic treatment should be tailored to the causative pathogen but at presentation the aetiology is rarely known, and patients therefore commonly receive empirical, often broad-spectrum antibiotics. …”

Randomised controlled trial and health economic evaluation of the impact of diagnostic testing for influenza, respiratory syncytial virus and Streptococcus pneumoniae infection on the management of acute admissions in the elderly and high-risk 18- to 64-year-olds

“…17,41,42 The test is often unhelpful, as positivity becomes evident no earlier than 24 hours after obtaining the specimen, and results typically have little influence on therapeutic decisions and outcomes. 41,[43][44][45] However, a review of patients with confirmed pneumococcal pneumonia found that 42% of patients with positive blood culture results had their treatment changed as a result. 46 As the overall prevalence of β-lactam resistance remains low in the UK, rapid near-patient testing for pneumococcal infection could influence therapeutic decisions.…”