Final answer:
The recommended antibiotic regimen for a 67-year-old obese male with left lower quadrant pain and fever is Metronidazole and ceftriaxone (Option 3).
Step-by-step explanation:
The recommended antibiotic regimen for a 67-year-old obese male with left lower quadrant pain and fever would be Metronidazole and ceftriaxone (Option 3). This combination is commonly used to treat intra-abdominal infections, which can manifest as left lower quadrant pain. Metronidazole is effective against anaerobic bacteria commonly found in the gut, while ceftriaxone provides broad-spectrum coverage against Gram-negative bacteria. It's essential to consider local resistance patterns and the patient's medical history, including prior antibiotic use and allergies, when selecting an antibiotic regimen. As always, treatment should be individualized, and the guidance of an infectious disease specialist may be warranted for complex cases.