Table 1.

Criteria used for the classification of isolates with respect to their biofilm formation

criteria	Biofilm-formation Capacity
ODs ≤ODc	No biofilm producer
ODc≤ ODs ≤ 2×ODc	Weak biofilm producer
2 × ODc ≤ ODs ≤ 4 × ODc	Moderate biofilm producer
4 × ODc <ODs	Strong biofilm producer

ODs (average of the optical density of sample).