07 common stains Flashcards
Stains Used When You Suspect Meningitis. what specimen do you stain?
Case 1 – suspected Meningitis
- Specimen – Cerebrospinal fluid (CSF)
- Possible pathogens:
- Bacteria (very common)
- Viruses (microscopy not done for diagnosis)
- Fungi
- Parasite (Rare)
- Gram stain – for bacteria
- India ink – for Cryptococcus
- Wet mount – for Naegleria
stain that detects bacteria*. what specimen do you stain?
Gram stain CSF - detects bacteria*
note:
- Gram positive cocci pairs
- Numerous neutrophils
- Indicates acute infection
- Knowledge gained:
- Bacterial meningitis confirmed
- Pathogen is most likely Streptococcus pneumoniae
- One of leading causes of bacterial meningitis
Indian ink prep stains?** what specimen do you stain?
India ink prep CSF – Cryptococcus neoformans (fungus) *
-
Encapsulated,spherical budding, refractile bodies with a black background
- Negative stain (the organism hasn’t taken up stain)
Knowledge gained:
- Fungal meningitis confirmed
- Pathogen - Cryptococcus neoformans
Wet mount stains for? what specimen do you stain?
Wet mount CSF – Naegleria (parasite)
- Motile amoeba +
- Numerous neutrophils
Knowledge gained:
- Primary amoebic meningoencephalitis confirmed
- Pathogen is Naegleria fowleri
- Appropriate treatment started
Note:
- This is an extremely rare infection
- If gram stain shows many neutrophils and no bacteria suspect this parasite
- As this is a parasite it will not respond to standard drugs used for bacterial meningitis
- Patient will die if not treated as soon as possible
stain used when you suspect malaria? what specimen do you stain?
Case 2 – suspected Malaria
- Specimen – peripheral Blood
- Suspected pathogen – Parasite
- Wright-Giemsa stain
what is the stain used when you suspect tuberculosis? what specimen do you stain?
Case 3 – suspected Tuberculosis
- Specimen – Sputum
- Suspected pathogen – Mycobacterium
- Stains:
- Ziehl-Neelsen (acid fast stain) *
- Kinyoun stain (acid-fast stain)
- Auramine-Rhodamine stain (fluorescent stain) *- green
- Note: Mycobacterial cell wall – mycolic acids *
- Confers “Acid-fastness”
- described as “Acid-fast bacilli” *- red
Water diarrhea stain.
Case 4 – Watery diarrhea
- Specimen – Fecal material
- Suspected pathogens:
- Bacteria (common causes but staining NOT used)
- Protozoan parasites (common – trophozoites , cysts)
- Sometimes helminths (ova, larva)
- Viruses
Stains:
- For parasites
- O&P exam *(Ova + cysts + trophozoites)
- Trichrome stain, Iron-hematoxylin stain
-
Modified acid fast stain – Cryptosporidium *
* should be suspected in AIDS patients with watery diarrhea
-
Modified acid fast stain – Cryptosporidium *
O&P examination of stool specimen
O&P examination of stool specimen
- Many cysts of Giardia
- Giardiasis confirmed
-
O&P exam of stool *
- iodine prep – cysts yellow
- Wet stain- cannot be preserved
- Iron-hematoxylin stain
- cysts are blackish
- Permanent stain – can be preserved
Modified acid-fast stain for stool does what? *
Modified acid-fast stain for stool does what? *
- AIDS patient with profuse, watery diarrhea
- This stain will pick up Cryptosporidium
- Also Isospora, Cyclospora and Microsporidia
- (all cause diarrhea in AIDS patients)
- Pinkish structures against a blue background
when would you suspect primary syphilis? what you do when you suspect Primary Syphilis
when would you suspect primary syphilis? what you do when you suspect Primary Syphilis
- Painless ulcer on genitalia
- Pathogen suspected – Treponema pallidum
- Specimen – exudate from ulcer/lesion
- Darkfield microscopy *
what stains do you use to look for bacteria?
what stains do you use for bacteria?
- ** Gram Stain***
- _ For Mycobacteria_
- Acid Fast Stain *
what stains do you use to look for Fungi
what stains do you use to look for Fungi
- KOH prep * (Potassium hydroxide)
- Calcoflour white stain
- India ink prep *
- Gram stain
what stains do you use to look for parasites?
what stains do you use to look for parasites?
- Wright- Giemsa *
- O&P exam - Iodine wet-mount * (Ova + cysts + trophozoites)
- Modified acid-fast stain *
- Iron -hematoxylin
- Trichome stain
What stains do you use to look for viruses
What stains do you use to look for viruses
• Electron microscopy
