OSMT (Ontario Society of Medical Technologists) Practice Exam

Cationic surface active agents are effective against:

1. a. gram positive organisms

2. b. gram negative organisms

3. c. both

4. d. neither

The correct answer is: c. both

Cationic surface active agents, commonly known as cationic surfactants, are known for their antibacterial properties and their effectiveness in disrupting the cellular membranes of microorganisms. These agents are generally effective against a variety of microorganisms, including both gram positive and gram negative organisms. Their cationic nature allows them to interact with the negatively charged components of bacterial membranes, leading to alterations in cell permeability and ultimately resulting in cell death. Gram positive organisms, which typically have a thicker peptidoglycan layer, are particularly susceptible to these agents due to the disruption of their cell walls. On the other hand, while gram negative organisms have an outer membrane that offers more resistance, cationic surfactants can still penetrate this barrier, especially at higher concentrations or through specific mechanisms. Thus, cationic surface active agents have broad-spectrum activity and are effective against both categories of bacteria, making the understanding of their mechanism and application valuable in medical microbiology and disinfection practices.