Table 15.

Laboratory Diagnosis of Mastoiditis and Malignant Otitis Externa Caused by Oropharyngeal and Exogenous Pathogens

Etiologic Agents	Diagnostic Procedures	Optimum Specimens	Transport Issues and Optimal Transport Time
Mastoiditis
Streptococcus pneumoniae  Haemophilus influenzae  Moraxella catarrhalis  Streptococcus pyogenes  Staphylococcus aureus  Pseudomonas aeruginosa  Enterobacteriaceae  Anaerobic bacteria	Gram stain Aerobic and anaerobic bacterial culture	Middle ear fluid obtained by tympanocentesis or biopsy of mastoid tissue; swab not recommended	Sterile anaerobic container, RT, immediately
Mycobacterium tuberculosis	Acid-fast smear AFB culture	Biopsy of mastoid tissue	Sterile container, RT, 2 h
Malignant otitis externa
Pseudomonas aeruginosa	Gram stain Aerobic bacterial culture	Scraping or fluid from external canal or tissue biopsy from temporal bone or mastoid	Sterile container, RT, 2 h

Abbreviations: AFB, acid-fast bacilli; RT, room temperature.