Can Nocardia be acid-fast stained?
Can Nocardia be acid-fast stained?
Nocardia are weakly acid-fast following staining with the modified Ziehl-Neelsen or Kinyoun stain. Cultures may grow in a few days, but typically require 2 to 3 weeks of incubation.
How do you stain Nocardia?
Procedure for modified Ziehl-Neelsen stain for Nocardia
- Make smear on a clean glass slide.
- Dry and fix the smear.
- Cover the smear with a strong carbol fuchsin solution.
- Wait for five minutes.
- Rinse with water.
- Decolorize by 1 % Sulphuric acid until the smear becomes pale pink in color. (
- Rinse with water.
How do you treat Nocardia?
Nocardia organisms are usually resistant to penicillin. Sulfonamide drugs may be prescribed. However, since most cases respond slowly, treatment with sulfonamide drugs must be continued for several months. Trimethoprim-sulfamethoxazole is often prescribed for immunosuppressed patients.
Which staining technique is used for bacteria belonging to genus Nocardia explain the procedure?
Acid-fast stain (AF) is an important special staining technique used in the histology lab. This is a differential stain used to identify acid-fast bacterial organisms, such as members of the genus Mycobacterium and Nocardia.
Why is Nocardia partially acid-fast?
Some species are partially acid-fast (meaning a less concentrated solution of sulfuric or hydrochloric acid should be used during the staining procedure) due to the presence of intermediate-length mycolic acids in their cell wall.
What kills Nocardia?
Sulfonamides, alone or in combination with trimethoprim, are the most effective first line agents against nocardiosis, and should be continued for several months to prevent a relapse, especially in immunocompromised patients.
What is modified acid-fast stain?
A modified acid-fast staining method was developed for rapid detection of Mycobacterium tuberculosis and its L forms, wherein carbol fuchsin and dioxogen were mixed into the sputum smear. With this method, the dyeing time is shortened and heating is not required.
What is the drug of choice for Nocardia asteroides?
Minocycline, moxifloxacin, and tigecycline are active against selected Nocardia species. Nocardia asteroides complex is a group of bacteria that have a heterozygous pattern of antimicrobial drug susceptibilities and are responsible for the majority of clinical human Nocardia infections.
How do you test for Nocardia?
Respiratory secretions, skin biopsy samples, and aspirates from abscesses are the most common specimens from which Nocardia species are identified. Direct smears or histopathologic stains of these specimens can be highly suspicious, as noted above. Nocardia species can usually be isolated in 3-5 days.
How do the Mycobacterium and Nocardia react to acid-fast stain?
Acidfast Stain: Background and Introduction. Mycobacterium and many Nocardia species are called acid-fast because during an acid-fast staining procedure they retain the primary dye carbol fuchsin despite decolorization with the powerful solvent acid-alcohol. Nearly all other genera of bacteria are nonacid-fast.
What type of bacteria is Nocardia?
Nocardia is a genus of weakly staining Gram-positive, catalase-positive, rod-shaped bacteria. It forms partially acid-fast beaded branching filaments (acting as fungi, but being truly bacteria). It contains a total of 85 species.
Why is methylene blue used in acid-fast staining?
After the auramine dye has fully stained the smear, a drop of acid alcohol is applied for one to two minutes to decolorize the smear. Methylene blue or potassium permanganate is used as a counterstain to provide background color.
