APPLYING SPUTUM AS A DIAGNOSTIC TOOL IN PNEUMONIA: LIMITED YIELD, MINIMAL IMPACT ON TREATMENT DECISIONS.

Ewig S, et al. Chest 2002 May;121(5):1486-92.

STUDY OBJECTIVES: We evaluated the role of sputum examination in the management of patients with community-acquired pneumonia (CAP) in a primary-care hospital without microbiologic laboratory facilities. Design and interventions: A diagnostic strategy using regular collection of sputum samples, Gram staining in a local laboratory, and mailing of samples to a commercial laboratory for culture analysis.

SETTING: A 200-bed primary-care hospital without subspeciality physicians.

PATIENTS: One hundred sixteen consecutive patients with a diagnosis of CAP were prospectively evaluated during a 12-month period.

RESULTS: Of 116 patients, 42 patients (36%) were capable of producing a sputum sample. Age > or = 75 years (odds ratio [OR], 0.4; 95% confidence interval [CI], 0.18 to 0.93) and prior ambulatory antimicrobial treatment (OR, 3.2; 95% CI, 1.2 to 8.4) were independent predictors of sputum production. A delay in collection and processing of sputum samples of > 24 h was present in 31% and 39%, respectively. A delay in collection yielded an increased number of Gram-negative enteric bacilli and nonfermenters (44% vs. 7%, p = 0.056). A delay in processing was associated with an increased number of Candida spp isolates (33% vs. 9%, p = 0.16). The overall diagnostic yield was low (10 of 116 patients, 9%) due to a limited number of valid samples (n = 23 of 42 patients, 55%) and a limited number of definitely or probably positive samples on Gram's stain and culture (n = 10 of 42 patients, 24%). Prior ambulatory antimicrobial treatment was associated with a reduction in diagnostic yield (14% vs. 56%, p = 0.09). The impact of diagnostic results on antimicrobial treatment decisions was minimal, with antimicrobial treatment directed to diagnostic results in only one patient.

CONCLUSIONS: We conclude that in this setting representative of primary-care hospitals in Germany, sputum had a low diagnostic yield and did not contribute significantly to patient management.

VALUE OF ROUTINE MICROBIAL INVESTIGATION IN COMMUNITY-ACQUIRED PNEUMONIA TREATED IN A TERTIARY CARE CENTER.

Ewig S, et al. Respiration 1996;63(3):164-9.

BACKGROUND: The study was conducted at a tertiary care and teaching hospital with about 200 beds for internal medicine. The objective was to determine the diagnostic yield and value in directing antibiotic therapy of a routine microbial approach in patients with community-acquired pneumonia referred to a tertiary care center.

SETTING: We studied 93 episodes in a retrospective study. 69/93 (74%) cases were treated with at least one empirical antibiotic therapy prior to admission.

RESULTS: Microbial investigation was performed in 83/93 cases (89%). An etiological agent was established in 19/83 (23%) cases including 7/50 (14%) by blood culture and 12/52 (23%) by serology. Bronchoscopy with 18 protected specimen brush and 20 bronchoalveolar lavage examinations was definitely diagnostic in only 1/25 (4%) cases, and this case was also identified by blood culture. 5/25 (20%) were probably diagnostic. Three pathogens, Streptococcus pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila, accounted for 15/19 (79%) of the identified agents. The diagnostic results directed a change in antibiotic therapy in 6/19 (32%) of cases with definitely proven pathogens. 4/19 (21%) of cases would have been treated with an inappropriate regimen without diagnostic results.

CONCLUSION: The diagnostic yield of routine microbial investigation in pretreated patients is low. The routine approach reveals its limited value especially in patients with severe courses. The role of bronchoscopy remains to be defined for patients with severe (and pretreated) community-acquired pneumonia.