Validation of sputum Gram stain for treatment of community-acquired pneumonia and healthcare-associated pneumonia: a prospective observational study

Abstract

BackgroundThe usefulness of sputum Gram stain in patients with community-acquired pneumonia (CAP) is controversial. There has been no study to evaluate the diagnostic value of this method in patients with healthcare-associated pneumonia (HCAP). The purpose of this study was to evaluate the usefulness of sputum Gram stain in etiological diagnosis and pathogen-targeted antibiotic treatment of CAP and HCAP.MethodsWe conducted a prospective observational study on hospitalized patients with pneumonia admitted to our hospital from August 2010 to July 2012. Before administering antibiotics on admission, Gram stain was performed and examined by trained physicians immediately after sputum samples were obtained. We analyzed the quality of sputum samples and the diagnostic performance of Gram stain. We also compared pathogen-targeted antibiotic treatment guided by sputum Gram stain with empirical treatment.ResultsOf 670 patients with pneumonia, 328 were CAP and 342 were HCAP. Sputum samples were obtained from 591 patients, of these 478 samples were good quality. The sensitivity and specificity of sputum Gram stain were 62.5% and 91.5% for Streptococcus pneumoniae, 60.9% and 95.1% for Haemophilus influenzae, 68.2% and 96.1% for Moraxella catarrhalis, 39.5% and 98.2% for Klebsiella pneumoniae, 22.2% and 99.8% for Pseudomonas aeruginosa, 9.1% and 100% for Staphylococcus aureus. The diagnostic yield decreased in patients who had received antibiotics or patients with suspected aspiration pneumonia. Pathogen-targeted treatment provided similar efficacy with a decrease in adverse events compared to empirical treatment.ConclusionsSputum Gram stain is highly specific for the etiologic diagnosis and useful in guiding pathogen-targeted antibiotic treatment of CAP and HCAP.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-534) contains supplementary material, which is available to authorized users.

Etiological analysis and epidemiological comparison among adult CAP and NHCAP patients in Okinawa, Japan

“…It is possible many pneumonia (35) 0.17 In-appropriate initial treatment 7 (7) 10 (10) 0.53 Changes to secondary treatment 10 (10) 9 (9) 0.92 Length of hospital stay, mean (SD) b 13 (17) 20 (18) 0.007* In-hospital mortality 1 (1) 9 (9) 0.01* a The outcome changes to initial treatment, includes patients for whom medication was changed for any reason, covering both at home use as well as potential treatment failure. b Outcome was compared using a Welch Two Sample t-test.…”

Fulminant Community-Acquired Hemorrhagic Pneumonia due to Pseudomonas aeruginosa in a Patient With Anorexia Nervosa

“…A case report on two cases of fulminant CAP due to P. aeruginosa suggested that gramnegative rods in sputum microscopy should be considered as a clue for an early diagnosis [8]. A recent study [16] assessing the usefulness of sputum Gram staining in the etiologic diagnosis of CAP showed that sputum Gram staining was highly specific for CAP due to P. aeruginosa (99.8%) in spite of the low sensitivity (22.2%). The result indicated that physicians should consider using antipseudomonal drugs when gramnegative rods are observed in the sputum of a patient with CAP regardless of the presence or absence of risk factors for P. aeruginosa.…”

Neumonía adquirida en la comunidad

“…Como antaño, en determinados centros avezados en la obtención de muestras de buena calidad y que disponen de microbiólogo durante las 24 horas del día, se obtienen buenos resultados con la tinción de Gram y posterior cultivo; sin embargo, las muestras salivares o procesadas tardíamente no tienen rentabilidad. La obtención de muestras mediante métodos invasivos, particularmente en pacientes de UCI, mejoran los resultados 44 . Se ha señalado que la ausencia de S. aureus en el frotis nasal descarta este microorganismo como patógeno potencial 45 .…”