Question

Triple Antibiotic Ointment contains Neomycin, Polymyxin B and Bacitracin and is sold across the counter to be applied topically to cuts and abrasions. This ointment is used to prevent infection and aid healing. Based on the results obtained using the Kirby-Bauer disk diffusion susceptibility test, would this ointment prevent infection by all four of the bacteria tested? Explain.

the four bacteria are

Staphylococcus aureus

Escherichia coli

Bacillus subtilis

Pseudomonas aeruginosa

Answer 1

In the case of Staphylococcus aureus, Triple Antibiotic Ointment would prevent infection. At a 1:1000 dilution of the ointment, resentence to Triple Ointment Antibiotic among Staphylococcus aureus was only found to be 5% which implies that it would help in the eradication of the infection and can be used for treatment.

It was found in a study done by the Australian scientists that all the gram-negative microorganisms were found inhibited by neomycin and/or polymyxin B components of TAO. Hence, E.coli being a gram-negative bacteria would be inhibited by the action of the ointment and thus can be used for the prevention of the infection.

Bacitracin is the antimicrobial agent produced from the Bacillus subtilis group of bacteria. Since they act against gram-negative bacteria it won't help in the prevention of the infection by Bacillus subtiis bacteria which is gram-positive.

In the case of infection caused by Pseudomonas aeruginosa, which is a gram-negative bacteria, there would be an inhibition being caused by the ointment. Thus it can be used for the treatment for infection against Pseudomonas aeruginosa.