Which statement about bacterial flora is correct?

The statement that resident flora are typically less virulent is correct. Resident flora, also known as normal flora, consist of bacteria that are normally found in and on the human body. These microorganisms play a crucial role in maintaining health by outcompeting pathogenic bacteria for nutrients and space, which can help to prevent infections.

Compared to transient flora, which may be more virulent and can introduce potential pathogens to the body, resident flora are generally well adapted to coexist with the host without causing disease under normal circumstances. This lower virulence contributes to their presence being a normal part of the body's ecosystem, providing protection and supporting the immune system.

The other statements do not accurately reflect the characteristics of bacterial flora. Transient flora can indeed cause infections but do not exclusively do so. Resident flora are not easily removed by washing since they are well established in the skin and mucous membranes. Lastly, while handwashing is effective against many types of bacteria, it may not eliminate all bacteria, particularly in cases of spores or certain resistant strains, but it is still a critical practice for infection control. This understanding highlights the importance of recognizing the differences between types of bacteria and their implications for health and infection management.