Final answer:
Acute glomerulonephritis cannot be prevented with antibiotics as it is an immune-mediated response that occurs after strep pharyngitis and is triggered by immune complexes between the bacteria and antibodies.
Step-by-step explanation:
The complication of strep pharyngitis that cannot be prevented with antibiotics is acute glomerulonephritis. While antibiotics are effective in treating the bacterial infection and can prevent suppurative complications like peritonsillar abscess and cervical adenitis, they cannot prevent the nonsuppurative sequelae such as acute rheumatic fever and acute glomerulonephritis. Both of these conditions are immune-mediated responses to the infection with specific strains of S. pyogenes that can develop even after the infection has been treated with antibiotics. However, between acute rheumatic fever and acute glomerulonephritis, prompt antibiotic treatment has been shown to reduce the incidence of acute rheumatic fever, not acute glomerulonephritis, which is triggered by immune complexes and the inflammatory response following the infection.