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Table 4 Diagnostic performance of sputum Gram stain in patients with CAP and HCAP

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

  CAP HCAP p value
n = 328 n = 342
No sputum sample, n (%) 55 (16.8) 24 (7.0) <0.001
Poor quality sample, n (%) 43 (13.1) 70 (20.5) 0.011
Good quality sample, n (%) 230 (70.1) 248 (72.5) 0.49
No meaningful microorganism, n (%) 30 (9.1) 27 (7.9) 0.56
Polymicrobial flora, n (%) 56 (17.1) 94 (27.5) 0.001
Predominant morphotype, n (%) 144 (43.9) 127 (37.1) 0.0744
Positive predict, n (%) 107 (32.6) 82 (24.0) 0.013
Sensitivity (%)    
Streptococcus pneumoniae 63.1 61.7
Haemophilus influenzae 76.8 44.4
Moraxella catarrhalis 85.0 54.2
Klebsiella pneumoniae 50.0 37.5
Pseudomonas aeruginosa 20.0 23.5
Staphylococcus aureus 50.0 0
Specificity (%)    
Streptococcus pneumoniae 89.7 93.0
Haemophilus influenzae 94.8 95.3
Moraxella catarrhalis 97.6 92.4
Klebsiella pneumoniae 98.7 99.5
Pseudomonas aeruginosa 100 99.6
Staphylococcus aureus 100