What are harmful microorganisms that can cause disease or infection in humans?

Pathogenic bacteria are indeed harmful microorganisms that can cause disease or infection in humans. These bacteria invade the body, multiply, and can produce toxins that harm cells and tissues, leading to various illnesses. Some examples of diseases caused by pathogenic bacteria include strep throat, tuberculosis, and urinary tract infections.

Understanding the role of pathogenic bacteria is crucial in the field of barbering and personal grooming, as they can be present on the skin or in other areas, leading to infections if proper sanitation and hygiene practices are not followed. Knowledge of these microorganisms can help barbers implement effective cleaning and disinfection protocols to prevent the spread of infections among clients.

While viruses, fungi, and protozoa can also cause diseases, the question specifically highlights pathogenic bacteria as the category that includes many well-known agents of disease, making it the most appropriate answer.