Which of the following differentiates Thayer-Martin medium from modified Thayer-Martin medium?

Thayer-Martin medium is a selective bacterial culture medium primarily used for the isolation of Neisseria gonorrhoeae, the pathogen responsible for gonorrhea. It is an enriched media that inhibits the growth of contaminating flora while allowing the desired organism to thrive.

The key distinguishing factor between Thayer-Martin medium and modified Thayer-Martin medium is the inclusion of trimethoprim lactate. Modified Thayer-Martin medium contains trimethoprim, which acts as an antibacterial agent that further suppresses the growth of competing bacteria, particularly gram-positive and some gram-negative organisms, by inhibiting their DNA synthesis. This addition enhances the selectivity of the medium, making it more effective for isolating Neisseria species in clinical specimens.

In the context of the other options, while substances like nystatin, vancomycin, and colistin can also be present in various formulations of selective media, they serve different roles. Nystatin targets fungi, vancomycin primarily acts against gram-positive bacteria, and colistin is effective against certain gram-negative bacteria. However, it is the presence of trimethoprim lactate in modified Thayer-Martin medium that specifically differentiates it from the standard Thayer-Mart