Used to aid in the diagnosis of otitis externa and otitis media.

There are several types of otitis externa: 
a) acute localized disease (a pustule or furuncle due to Staphylococcus aureus)
b) erysipelas caused by group A streptococci
c) acute diffuse otitis externa (swimmer's ear) caused mainly by Pseudomonas aeruginosa and sometimes other gram-negative bacilli
d) hemorrhagic otitis externa due to P. aeruginosa (hot tub use)
e) chronic otitis externa due to suppurative drainage from the middle ear
f) malignant otitis externa (necrotizing) seen in diabetics, caused mainly by P. aeruginosa and anaerobes

The cause of otitis media is best determined by culture of a specimen obtained by tympanic membrane aspirate (tympanocentesis) after cleansing of the external canal.

Guidelines for identification and susceptibility testing of isolates are based on source, method of collection, and numbers of different isolates and specific potential pathogens present.

Cultures of otitis externa (material collected by swab) often contain normal skin flora such as diphtheroids and staphylococci which make the culture results difficult to interpret.

Acute otitis media (middle ear infection) is common in children three months to three years old.  In children, S. pneumoniae, H. influenzae, and group A streptococci are the usual etiologic agents. Other organisms, encountered less frequently include M. catarrhalis, S. aureus, gram-negative enteric bacilli, and anaerobes.
Chronic otitis media and its complication, mastoiditis, are usually caused by anaerobic bacteria, especially Peptostreptococcus spp., B. fragilis group, pigmented Prevotella and Porphyromonas spp., other Bacteroides spp., and Fusobacterium nucleatum. Less common pathogens include aerobes such as S. aureus, P. aeruginosa, Proteus spp., and other gram-negative facultative bacilli.

Aerobic culture and Gram Stain. 

Includes identification and susceptibility testing when appropriate at additional charges. 

CPT coding cannot be determined before culture is completed.

For culture for anaerobes from tympanocentesis fluid, order "Culture, Aerobes and Anaerobes, other w Gram Stain".