What is the Petroff method?
Decontamination and concentration of sputum specimens by modified Petroff’s method is one of the most commonly used methods for M. tuberculosis culture. N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) solution is recommended as a gentle but effective digesting and decontaminating agent.
How will you decontaminate the sputum specimen?
Sputum culture is more sensitive than ZN microscopy and also facilitates drug susceptibility testing. In order to get a viable culture, the sputum specimens should be decontaminated with 4% sodium hydroxide to kill contaminating bacteria and preserve mycobacteria without much effect on their survival.
What is used in digestion and decontamination of sputum in smear preparation?
In addition they require, prior to cultivation of respiratory specimens, that they be treated by the most commonly used digestion-decontamination method, N-acetyl-L-cysteine–sodium citrate–NaOH (NALC-NaOH), which also increases the total cost of the culture considerably (Kubica et al 1963; Palomino et al 1999).
What media does Mycobacterium tuberculosis grow on?
Mycobacterium tuberculosis is a slow-growing bacterium that is the etiological agent of tuberculosis. Agar-based and egg-based media incorporating green malachite and Middlebrook broths or solid media are recommended as the “gold standard” for isolation, culture, and definite diagnosis of M.
What is Ziehl Neelsen stain used for?
Ziehl–Neelsen staining is a bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria. It is named for two German doctors who modified the stain: the bacteriologist Franz Ziehl (1859–1926) and the pathologist Friedrich Neelsen (1854–1898).
What tests are done to diagnose TB?
The Mantoux tuberculin skin test (TST) or the TB blood test can be used to test for M. tuberculosis infection. Additional tests are required to confirm TB disease. The Mantoux tuberculin skin test is performed by injecting a small amount of fluid called tuberculin into the skin in the lower part of the arm.
What is decontamination process?
Decontamination is a combination of processes that removes or destroys contamination so that infectious agents or other contaminants cannot reach a susceptible site in sufficient quantities to initiate infection, or other harmful response.
What is NALC Naoh method?
N-Acetyl-L-cysteine (NALC) is a mucolytic agent that at concentrations of 0.5 to 2.0% can rapidly digest even tenacious sputa from cystic fibrosis patients within 2 minutes. Decontamination is achieved by the addition of sodium hydroxide.
How are mycobacteria cultured?
To obtain a sample, you will be asked to cough deeply and spit out the material that comes up from your lungs. A biopsy or aspiration may also be done. The sample is sent to a laboratory. There it is placed in a special dish (culture).
How is LJ Media sterilized?
Preparation of LJ Medium Dissolve 37.3 gm of the medium in 600 ml of distilled water containing 12 ml of glycerol. Heat if necessary to dissolve the medium completely. Autoclave at 121°C for 15 minutes.
Why is the Ziehl neelsen method called the hot method?
The Ziehl-Neelsen method of staining is also called the hot method as it involves heating the carbolfuchsin stain. In contrast, the historic method of staining called the Kinyoun method does not involve heating and is hence known as the cold method.
How is Ziehl neelsen method different to Kinyoun method?
Unlike the Ziehl–Neelsen stain (Z-N stain), the Kinyoun method of staining does not require heating. In the Ziehl–Neelsen stain, heat acts as a physical mordant while phenol (carbol of carbol fuschin) acts as the chemical mordant.