Final answer:
The treatment of choice for Pneumocystis pneumonia (PCP) is Bactrim, for cystic fibrosis exacerbation it's Aztreonam, Clindamycin for a lung abscess, Penicillin G for Streptococcal pneumonia, and Voriconazole for Invasive pulmonary aspergillosis.
Step-by-step explanation:
The treatment of choice for various respiratory conditions relies on targeting the specific pathogens responsible for the infection. For Pneumocystis pneumonia (PCP), which is caused by the fungus Pneumocystis jirovecii, the preferred treatment is Bactrim, a combination of sulfamethoxazole and trimethoprim.
This can be administered either orally or intravenously, and alternatives include atovaquone or pentamidine. In the case of cystic fibrosis exacerbation where Pseudomonas aeruginosa is a common pathogen, Aztreonam may be used for its effectiveness against this particular bacterium.
A lung abscess, which can be bacterial in origin, is often treated with Clindamycin due to its anaerobic coverage. For Streptococcal pneumonia, caused by Streptococcus pneumoniae, the first-line treatment has traditionally been Penicillin G, although resistance is increasing and alternatives may be necessary. Lastly, Voriconazole is the treatment of choice for Invasive pulmonary aspergillosis, a serious fungal infection of the lungs.