Final answer:
A local infection is characterized by a lesion containing pus, with examples including boils and abscesses typically caused by bacterial infection.
Step-by-step explanation:
A local infection appears as a lesion containing pus and is confined to a particular part of the body. These infections can manifest in various ways, such as folliculitis or boils (furuncles), which are typically caused by a bacterial infection like Staphylococcus aureus. These boils are pus-filled swellings on the skin that result from the infection of hair follicles. Abscesses, another type of pus-filled lesion, are deeper than boils and may form when multiple furuncles coalesce. Observing bacteria under a microscope after sampling the lesion can help identify features such as shape, size, and the presence of certain structures that can give clues about the type of bacteria causing the infection.
The localized nature of these infections indicates that the pathogens are limited to small areas, not spreading systemically throughout the body. Pus production indicates that the body's immune system is reacting to the infection, and this pus can be a mixture of dead tissue, white blood cells, and bacteria. In a clinical setting, swabbing and analyzing these infections help in determining the appropriate treatment, such as prescribing antibiotics.