Bacteria are robust micro-organisms that can survive even in the presence of antibiotics. This has led to problems treating bacterial infections. Bacteria are the most common cause of infection and Streptococcus pneumoniae is one such infection. This bacterium causes community-acquired pneumonia in older people and, though immunisation is available, older people continue to die from pneumococcal pneumonia. Penicillin continues to be used as the main method of treatment against Streptococcus pneumoniae but antibiotic resistance is increasing