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The primary goal of Sherris Medical Microbiology is to help students of medical sciences understand how microbes pathogenic to humans cause infectious disease. The approach is a classic biologic one connecting basic science (structure, metabolism, genetics) to disease science (epidemiology, pathogenesis, immunity) for each microbe category (viruses, bacteria, fungi, parasites) and eventually, the individual pathogens. For each of the major pathogens, we also present clinical science (manifestations, diagnosis, treatment, prevention) both to illuminate disease understanding and as preparation for clinical application. Everyone knows that clinically, infectious diseases do not present as microbes but as patients with complaints, lesions, and laboratory findings. The challenge of their effective management involves a deductive process that begins with the clinical (fever, cough, age, season) and proceeds to the etiologic (Influenza A, Staphylococcus aureus, Candida albicans, Plasmodium falciparum). This supplement includes listings of the most common infectious syndromes followed by tables that present which infectious agents most commonly produce disease in those circumstances. In a few instances where laboratory findings are crucial to the decision process they are included as well.



Folliculitis is a minor infection of the hair follicles. It is often associated with areas of friction and of sweat gland activity and is thus seen most frequently on the neck, face, axillae, and buttocks. Blockage of ducts with inspissated sebum, as in acne vulgaris, predisposes to the condition. Acne vulgaris also involves inflammation of hair follicles and associated sebaceous glands.


The furuncle is a small abscess that develops in the region of a hair follicle. Furuncles may be solitary or multiple and may constitute a troublesome recurrent disease. Spread of infection to the dermis and subcutaneous tissues can result in a more extensive multiloculated abscess, the carbuncle.


Pyoderma, also termed impetigo, is a common, sometimes epidemic, skin lesion. The initial lesion is often a small vesicle that develops at the site of invasion and ruptures with superficial spread characterized by skin erosion and a serous exudate, which dries to produce a honey-colored crust.


Erysipelas is a rapidly spreading infection of the deeper layers of the dermis. It is associated with edema of the skin, marked erythema, pain, and systemic manifestations of infection including fever and lymphadenopathy.


Cellulitis is not a skin infection as such, but it can develop by extension from skin or wound infections. It usually manifests as an acute inflammation of subcutaneous connective tissue with swelling and pain and often with marked constitutional signs and symptoms.

Wound Infections

Wounds subject to infection can be surgical, traumatic, or physiologic. The latter include the endometrial surface, after separation of the placenta, and the umbilical stump in ...

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