Misc Body Sites (Ear, Genital and Cath tip) Flashcards
Common ear infections?
Otitis media (middle ear infection) Otitis externa (swimmer's ear) - caused by Psuedomonas
When is susceptibility testing done for ear cultures?
On any single isolate that is a potential pathogen, predominant or pure
Common contaminating flora for ear cultures?
Coagulase negative staph
Diptheroid bacilli
Bacillus sp.
What does accurate diagnosis of genital culture depend on?
Separation of pathogens from normal flora
T or F? You must know the exact source information of the specimen to determine workup.
True
When do you not do a direct gram stain for a genital culture?
When it is a vaginal culture
Common cause of infections around IUDs?
Actinomyces
What organism are you looking for in a wet prep with clue cells?
Gardernella vaginalis
What are the guidlines for interpreting direct gram stain results from a genital culture?
PMNs and no/few SECs - good
SECs and no/few PMNs - poor
When is susceptibility testing for genital cultures appropiate?
They are not routinely performed except for from a “sterile” genital source (surgically obtained)
Laboratory testing for N. gonorrhoeae?
Molecular assays, and cultures (not routinely performed except when susceptibility test is indicated)
Besides the genitals, where else do you commonly see N. gonorrhoeae infections?
Rectum, throat, blood, skin lesions, or joint fluid
What is the transport media for N. gonorrhoeae?
Jembec plate (Modified Thayer Martin) media
What tests are done on growth from Jembec plate?
Gram stain (GNDC) and oxidase (pos)
Which organism found in vaginal cultures may be a cause of systemic disease to newborn if contracted during pregnancy?
Group B strep (GBS)
What is the national standard for screening pregnant women for GBS?
32-35 weeks
What are the accepted specimen types for GBS?
Perianal and genital (common), also cervix and vagina
What special broth culture is used to detect GBS? What does a positive result look like?
Carrot Broth (starch, peptones serum with inhibitors) + nutrient enrichment tiles with pigment production; a positive result is an orange pigment
What is the Denver health standard for susceptibility tests on GBS?
Test for Clindamycin SS for all pregnant women
What is done after receiving a positive result for GBS in carrot broth?
Subculture and isolate on BAP
Which type of GBS is carrot broth not sensitive for?
Non-hemolytic GBS
What is the standard for testing negative results in carrot broth?
Subculture to BAP and look for suspicious non-hemolytic colonies @24-48 hrs
T or F. Nosocomial bloodstream infections are often cath-tip related.
True
What also must be done concurrently with cath tip cultures?
Blood cultures
What is the purpose of cath tip culture?
To determine true sepsis from contamination
How does most cath tip septicemia begin?
As localized infection of the intradermal catheter wound
What is the cause of cath tip septicemia?
Migration of skin organisms at the insertion site into cutaneous catheter, colonization of the cath tip
What are the common causes of cath tip infections?
Coag negative staph (especially), candida sp, enterococci, and staph aureus
What are the keys to interpreting cath tip cultures?
Determining whether the organisms recovered is the same from blood culture; # of colonies that grow directly relate to whether cath tip is source of infection
Which colonies are counted from a cath tip culture?
All of them
What are the rules of numbers of colonies worked up from cath tip culture?
Isolate > = 15 significant colonies - ID/MICs, preferably from blood culture isolate
Isolate < 15 if colonies not significant - report organisms with descriptive ID
