Monday, October 14, 2013

Chronic suppurative otitis media

When the eardrum has been perforated in an acute attack of otitis media and remains patent infection with the original pathogens may persist or repeated infections may be caused by secondary invaders such as S. aureus coliform bacilli, Pseudomonads and bacteroides. Swabs of the discharge in the external meatus should be cultured to guide the choice of antibiotics for systemic and topical therapy, but it must be borne in mind that such swabs are liable to be contaminated with commensal bacteria from the skin lining the meatus. These contaminants are mainly albus Staphylococci diplitheroid bacilli and saprophytic mycobacteria which should be ignored but may include s. aureus and coliform bacilli.
Otitis externa. Chronic inflammation of the skin of the external meatus, with irritation and discharge, may be caused by bacteria, particularly Pseudomonas aerugjnosa colifoon bacilli and S. aureus, or fungi, most commonly Candida or Aspergillus. A swab should be taken from the meatus and cultured aerobically on blood agar and MacConkey plates for the bacteria on a Sabouraud agar plate with a nystatin 50 Unit disk for 48h at 35-37°C for Candida and on a Sabouraud agar for 10 days at 28°C for Aspergillus . The results will guide the choice of drug for topical antibacterial or antifungal treatment.

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