Unit 2: Difficult Problems in Otitis Flashcards
Most difficult cases are NOT the result of _____ (3 things).
- Resistant organisms (MDR)
- Strange conformational problems
- Infections with rare organisms
What are difficult cases created by?
Inadequate treatment, chronic changes/biofilm production, failure to ID and control the primary factor, and lack of client commitment
What are some difficult problems you may encounter in practice?
“Allergic” ears, Malassezia infections, Pseudomonas infections, ceruminous otitis externa, hyperplastic ear changes
What are the 7 best practices in the management of otitis?
- Use appropriate diagnostics
- Prepare the canal for treatment
- Choose treatment wisely
- Meds must be administered properly
- Use quality control to evaluate treatment
- Consider long-term maintenance therapy
- ID and control primary factor(s)
Pseudomonas infections are suspected with unusually _____ ears.
painful
What is seen on cytology with a Pseudomonas infection?
Single population of Gram(-) rods
What is the etiology behind Pseudomonas infections?
Same primary factors as all otitis cases (atopy, masses, endocrinopathy, AI disease);
It is almost always a secondary bacterial invader after previous antibiotic therapies
What do you see at the opening of the canal with Pseudomonas infections?
Mucopurulent, sticky material
Swollen, sore, painful
What is the relationship between biofilm and MIC?
MIC of drugs like polymyxin B, enrofloxacin, and gentamicin is significantly higher for biofilm producers
What is biofilm?
Matrix of proteins in a sticky, gel-like substance containing sugary strands (EC polymeric substances)
What are the EC polymeric substances?
Polysaccharides, proteins, EC DNA
Where do bacteria live in biofilm?
In clusters separated by channels
Why is biofilm a good defense mechanism?
Provides protection from abx, antibodies, and phagocytes
What % of human infections are associated with biofilm?
80%
What are the mechanisms of antimicrobial intolerance?
- Antimicrobial depletion (agent doesn’t reach biofilm)
- Slow penetration (gives cells a chance to initiate stress response)
- Stress response (cells change activity in response to challenge)
- Altered microenvironment (metabolically inactive - alive)
- Persister cells (spore-like cells that can survive an antimicrobial challenge)
What are some advantages that bacteria have?
Structural stability, firm adherence to biotic/abiotic surfaces, increased virulence, resistance to antimicrobial therapy, resistance to host immune response
How may cells be dispersed in biofilm?
Shedding of daughter cells, detachment as result of nutritional levels or quorum sensing, shearing of biofilm aggregates
T/F: We should never assume that Pseudomonas and Staph otitis form biofilm.
False - we should assume that they all produce biofilm
What is the most important aspect of management of Pseudomonas otitis?
cleaning the ears
Why is cleaning the ears important?
Removes barriers to topical administration (wax, debris, biofilm), decreases bacterial burden, removes material (pus) that may inactivate meds
What does deep cleaning under anesthesia allow for?
Evaluation of the tympanic membrane and allows use of topical antiseptic
What is a good way to do a deep ear cleaning for Pseudomonas infections?
Flush with body temp saline
Ensure the ear drum is intact
Put in betadine (toxic to middle ear)
Allow to sit then flush out
Some cleansers show _____ activity vs. Pseudomonas.
antimicrobial
How can you maximize the value of your treatment?
Use cultures appropriately, understand the impact of biofilm, and use materials that lower MICs (i.e. Tris-EDTA, N-acetylcysteine/acetic acid)
