In vitro analysis of antibiotic solutions and their effectiveness in inhibiting bacterial growth

Within a limited time of excision and grafting autografts can be compromised or lost due to infection. An in vitro study was done to test susceptibility of four antibiotic solutions against the most common bacteria found in the University of Utah's Intermountain Burn Center. Cost analysis of each antibiotic solution was also addressed. Utilizing two rows of Whatman filter paper disks on four separate Mueller-Hinton agar plates, antibiotic solutions were applied in two volumes and placed in a 35°C incubator for 16 hours. Zones of inhibition were measured and 'susceptibility vs resistance' was determined. It was found that against Acinetobacter baumannii, Methicillin-resistant Staphylococcus aureus (MRSA), and Staphylococcus aureus, 25% Chlorhexidine Gluconate (Hibiclens) in sterile water, demonstrated superior susceptibility over 5% Mafenide Acetate (Sulfamylon), 1/4 strength Acetic Acid (AA) and TABI solutions (Bacitracin 10,000u/me, Neomycin 2%, Polymyxin 500,000u, 1/2cc Iodine in 1000ml saline). Pseudomonas aeruginosa was most susceptible to AA solution followed by Sulfamylon. Patient charges for 24-hours utilization of solution showed AA as the least expensive followed by Hibiclens, TABI and Sulfamylon.