Microbiological testing of the otolaryngologic secretion is performed to investigate the microbial causes of external and middle otitis.
External otitis media
In general, contamination of the external auditory canal resembles contamination of the skin and soft tissues elsewhere in the body. However, there are some notable differences. The external auditory canal is narrow and as a result foreign bodies and fluids can get trapped, causing surface tissue irritation. External otitis can be divided into several categories: acute localized, acute diffuse, chronic and malignant. However, with the exception of malignant external otitis, other external otitis media are rarely differentiated in clinical practice.
I. Acute localized external otitis
Acute localized external otitis is usually caused by the Staphylococcus aureus germ.
II. Acute diffuse external otitis
Acute diffuse external otitis is a common disease in adults with frequent relapses. It is also known as "swimmer's ear" and occurs mainly in warm and humid conditions. Many different bacteria cause this infection, with the most common being Pseudomonas aeruginosa and Staphylococcus aureus. Rarely, acute diffuse external otitis media is caused by anaerobic microorganisms derived from the oropharynx.
III. Chronic external otitis
Chronic external otitis is due to colonization with E. coli and fungi and the best treatment involves local cleansing rather than antibiotics.
IV. Malignant external otitis
Clinically, the most important form of external otitis is malignant external otitis. Malignant external otitis is a severe necrotic inflammation that spreads from the squamous epithelium of the auditory canal to surrounding soft tissues, blood vessels, cartilage and bones. Patients at risk for developing the disease are people with diabetes, elderly and immunosuppressed patients. It is a life-threatening condition, with a significant risk of neurological involvement and paralysis of the facial nerve.It is almost always caused by Pseudomonas aeruginosa.
Otitis media
Acute otitis media is defined by the coexistence of fluid in the middle ear and signs and symptoms of acute disease. It can occur when flora of the mouth colonizes the Eustachian trumpet and is not treated by the middle ear defense mechanisms. Middle otitis is a common condition in children with frequent relapses. It is important to treat mild otitis media effectively, as possible complications include hearing loss. This in turn could have very adverse effects on the development of speech and behavior in children.
I. Acute otitis media
The most common microorganisms causing this infection are S. pneumoniae, H. influenzae and M. catarrhalis. The least common causes are S. pyogenes, S. aureus and some Gram-negative bacteria. Respiratory syncytial virus (RSV) and paravirus viruses have been isolated from patients with otitis media and may play a role in the etiology of the disease, especially in children.
II. Chronic suppurative otitis media
Chronic otitis media is highly destructive, persistent and can cause irreversible damage, such as hearing loss. The most common bacterial causes are Pseudomonas followed by a frequency of methicillin resistant Staphylococcus aureus (MRSA) and anaerobic bacteria in 25% of patients.
Fungal otitis
Fungal infection of the ear is a superficial, chronic or subcutaneous infection of the external auditory canal. Partial deafness may be caused by obstruction of the external auditory canal with fungal hypha. Fungi associated with out-of-ear infection are Aspergillus species, Scedosporium apiospermum (Pseudallescheria boydii) as well as other fungi and yeast.
Important Note
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.
