Final answer:
The 14-year-old male with 25 comedones and 20 inflammatory lesions without nodules has moderate acne. Propionibacterium acnes contributes to acne by infecting sebum-clogged pores, which can cause inflammation and various types of lesions.
Step-by-step explanation:
Classification of Acne Severity
The severity of acne is graded based on various factors including the number of comedones, inflammatory lesions, and the presence or absence of nodules. Given that the 14-year-old male in the question has 25 comedones and 20 inflammatory lesions with no nodules, his condition can be classified as moderate acne. Treatment for moderate acne may involve a combination of topical treatments like benzoyl peroxide, antibiotics like erythromycin or clindamycin, and possibly hormones.
Role of Propionibacterium acnes
Propionibacterium acnes plays a significant role in the formation of acne by infecting sebum-clogged pores. This bacterium is a common skin resident that consumes components of sebum and can lead to inflammation and the formation of different types of lesions, such as papules, pustules, and possibly nodules or pseudocysts in more severe cases.