CASE HISTORY In the Indian State of Bihar,a School Nurse Noticed That

CASE HISTORY
In the Indian state of Bihar,a school nurse noticed that a 13-year-old boy,Naranjan,had swelling on his nose and lips.When questioned,Naranjan complained of a pruritic (itchy) rash on his arms and legs.Upon examination,the nurse found pale patches of skin on his back.The pale patches lacked sensation,and there was partial loss of sensation in Naranjan's wrists and forearms.The patient was diagnosed with leprosy,caused by the bacterium Mycobacterium leprae.The bacteria stain acid-fast and are spread primarily by nasal secretions.For unknown reasons,only 5% of people exposed to the bacteria are susceptible to infection.In a susceptible host,the bacteria can grow slowly for many years without symptoms.They infect the peripheral nerves,causing loss of sensation,and the body's immune reaction generates skin lesions.To halt the disease,Naranjan was started on a two-year course of multidrug therapy combining dapsone,clofazimine,and rifampin.To monitor hepatotoxicity,liver function tests were ordered.Naranjan's family and neighbors were screened;one member,an uncle,showed skin lesions.The uncle was treated also.Leprosy is difficult to eradicate because of the long incubation period and because people hide their symptoms,fearing stigma as "lepers."
Mycobacterium leprae,or leprosy disease,often takes years to develop.Naranjan must use a long-term multidrug therapy to cure it.Why is it necessary to take the drugs for such a long period,and why must he take so many drugs at once?

A) Mycobacteria are Gram-negative organisms. They must be killed slowly to prevent release of toxic LPS.
B) Mycolic acid within the cell wall reduces nutrient uptake, resulting in slow growth, and excludes some antibiotics.
C) Mycobacteria are all highly resistant to antibiotics.
D) Mycobacteria don't have cell walls, so must be treated with antibiotics that target other structures.