Question

Microbiology - Describe three ways that microbes can avoid destruction by phagocytosis.

Answer 1

Phagocytosis is one of the defense mechanisms due which human body is able to resist microbial infections. Phagocytes engulf the foreign pathogens thereby destroying them and thus attenuating the disease probability. However, microbes use several strategies to circumvent this defense mechanism in order to show pathogenic effect, culminating in disease.

1. Certain microbes remain confined to regions secluded from phagocytes (lumens of glands, urinary bladder) and thus avoid phagocyte encounter.

2. Phagocytic defense is evoked by inflammatory response. Certain pathgenic microbes do not induce inflammatory response and thus trigger leading to phagocytosis is nullified.

3. Chemotaxis plays a cardinal role in phagocytosis by attracting phagocytes to the sites of infection. Certain bacteria or their products restrain phagocyte chemotaxis. For instance, Streptococcal streptolysin and Clostridium ø toxin prevents neutrophill chemotaxis and thus overcome phagocytic defense.