Final answer:
The most common organisms responsible for chronic suppurative otitis media are Staphylococcus aureus and Pseudomonas aeruginosa, with the latter known for its antibiotic resistance. In contrast, Streptococcus pneumoniae and Haemophilus influenzae are often the causative agents of acute otitis media, particularly in children.
Step-by-step explanation:
Chronic Suppurative Otitis Media: Causative Organisms
The most common organisms responsible for chronic suppurative otitis media (CSOM) are Staphylococcus aureus and Pseudomonas aeruginosa. These bacteria are known for their ability to resist many antibiotics. Pseudomonas aeruginosa, in particular, can produce ß-lactamases, has mutations that affect porins, and can pump antibiotics out of the cell, all of which contribute to its resistance. Additionally, Staphylococcus aureus is a well-known pathogen that can cause a variety of infections, including those in the ear.
In contrast, the usual causative agents of acute otitis media (AOM) among different age groups vary. Among neonates, Streptococcus pneumoniae is most common, while in older infants and children up to 14 years, the most common bacterial causes are S. pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. For AOM, Streptococcus pneumoniae and Haemophilus influenzae are significant, with the latter not possessing a capsule unlike encapsulated strains of S. pneumoniae.
Therefore, when considering the options provided for the most common organisms causing chronic suppurative otitis media, the correct answer is: a) Staphylococcus aureus and Pseudomonas aeruginosa.