Influence of Laboratory Culture Media on In-vitro Growth, Adhesion and Biofilm Formation of Pseudomonas aeruginosa and Staphylococcus aureus.

OBJECTIVE: Pseudomonas aeruginosa and Staphylococcus aureus dual species biofilm infections are notoriously difficult to manage. This study was aimed at investigating the influence of four different culture media on the planktonic growth, adhesion and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus.

MATERIALS AND METHODS: We monitored four different culture media including Nutrient broth (NB), Brain Heart Infusion (BHI) broth, Luria-Bertani (LB) broth and RPMI 1640 medium on the planktonic growth, adhesion and biofilm formation of Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 25923) using MTT assay and scanning electron microscopy (SEM).

RESULTS: The most robust growth of the mono and dual species cultures was noted in BHI broth. On the contrary, RPMI 1640 medium promoted maximal initial adhesion of both the mono and dual species but BHI broth fostered the maximal biofilm growth. SEM images showed profuse extracellular polysaccharide production in biofilms particularly in co-culture, in BHI medium.

CONCLUSION: Our data demonstrate that BHI broth, relative to other tested media, is the most conducive for in vitro evaluation of biofilm and planktonic growth kinetics of these two pathogens, both in mono- and co-culture.