Final answer:
For lung abscess, first-line treatment commonly includes ß-Lactams like penicillin. Macrolides or fluoroquinolones may be used when resistance is a concern. Tailored therapy, based on culture results or clinical indication, ensures effectiveness against the identified or suspected pathogens.
Step-by-step explanation:
The treatment for a lung abscess typically begins with a course of antibiotics, tailored to target the pathogens suspected or identified as the cause. In the case of gram-positive pathogens like pneumococci, ß-Lactam antibiotics such as penicillin are the standard first-line drugs. However, when there is concern over ß-Lactam resistance, alternative antibiotics such as macrolides (for example, clarithromycin or azithromycin) or fluoroquinolones may be prescribed.
Despite the use of these antibiotics, resistance can still develop, posing challenges to treatment effectiveness. When patients like John, whose condition deteriorates despite antibiotic therapy, indicating potential resistance or an atypical pathogen, it's essential to explore further. His physician's decision to add levofloxacin, after identifying Legionella pneumophila as the causative agent, exemplifies the need for tailored antibiotic therapy based on culture and sensitivity results or clinical suspicion. Continuing to monitor the patient's reaction to the revised antibiotic regimen is crucial, as is ensuring the patient completes the entire course of treatment to reduce the risk of relapse or resistance development.