Table 2: The frequency of positive culture according to disease severity

Disease severity	Culture		Total
Disease severity	Positive	Negative	Total
Mild	10 (66.7%)	5 (33.3%)	15
Moderate	18 (72%)	7 (28%)	25
Severe	9 (90%)	1 (10%)	10
Total	37 (74%)	13 (26%)	50