Stepwise model to differentiate pathogenic from non-pathogenic organisms in lower-respiratory isolates: Effectiveness and feasibility prospective cohort study

Table 3 Comparison of variables across the investigator’s classification of respiratory isolates

Parameters	Pathogenic commensal (n = 3)	Pathogenic colonizer (n = 103)	Pathogenic direct (n = 25)	Non-pathogenic commensal (n = 1)	Non-pathogenic colonizer (n = 5)	Non-pathogenic contaminants (n = 8)	P value
Age (years), mean ± SD	40.00 ± 19.52	50.67 ± 16.46	50.20 ± 16.10	30.00 ± 0	58.40 ± 5.90	49.38 ± 19.40	0.5591
Gender: Male (%)	33.3	49.5	76.0	100.0	80.0	62.5	0.0952
Gender: Female (%)	66.7	50.5	24.0	0.0	20.0	37.5	0.0952
Sample type: Sputum (n = 24)	100	0	68.0	100	0	37.5	< 0.001
Sample type: ET/TT (n = 96)	0	84.5	4.0	0	80.0	50.0	< 0.001
Sample type: BAL (n = 25)	0	15.5	28.0	0	20.0	12.5	< 0.001
Fever (%)	33.3	43.6	88	0	33.3	50	< 0.001
Cough (%)	66.7	56.4	88	0	66.7	83.3	0.0182
Increasing oxygen requirement, n (%)	1 (33.3)	87 (86.1)	16 (64.0)	0 (0)	1 (33.3)	2 (33.3)	< 0.0012
Increase in Sequential Organ Failure Assessment score ≥ 2 (%)	66.7	85.4	72.0	0	0	37.5	< 0.001
Shock (%)	0	43.7	24.0	0	0	0	0.009
Multiple organ dysfunction syndrome (%)	0	55.3	40.0	0	40.0	25.0	0.122
VAP (%)	0	48.5	20.0	0	20.0	12.5	0.011
Risk factors
Mechanical ventilation (%)	0	93.2	0	0	100.0	25.0	< 0.001
Recent hospitalizations/antibiotics (%)	66.7	69.9	16.0	0	100.0	37.5	< 0.001
Poor oral hygiene (%)	66.7	45.6	8.0	0	60.0	25.0	0.001
Chronic obstructive pulmonary disease (%)	33.3	24.3	4.0	0	60.0	12.5	0.030
Bronchiectasis (%)	66.7	0	0	0	20.0	0	< 0.001
Tracheostomy (%)	0	23.3	0	0	20.0	0	0.030
Response to treatment							< 0.001
Improved	100	43.70	80.00	-	-	-
No response	0	56.30	20.00	-	-	-
Not treated	-	-	-	100.00	80.00	87.50
Stable (non-pathogen) with treatment				0	20.00	12.50
Outcome: Mortality (%)	0	50.6	16.0	0	0	14.3	0.001

ET/TT: Endotracheal tube/tracheostomy tube; BAL: Bronchoalveolar lavage; VAP: Ventilator-associated pneumonia.