Pot method for storage & detection of acid-fast bacilli from sputum samples

Area of Science:

• Microbiology
• Public Health
• Diagnostic Pathology

Background:

• Sputum acid-fast bacilli (AFB) microscopy is crucial for tuberculosis diagnosis but lacks availability in many health facilities.
• Alternative methods for sputum sample transport are essential to reach diagnostic centers.
• The Ziehl-Neelsen (ZN) method is the standard for AFB detection.

Purpose of the Study:

• To evaluate the efficacy of the pot-method for preparing sputum smears compared to direct smears.
• To assess the feasibility of storing sputum samples for up to seven days using a preservation solution.

Main Methods:

• Sputum samples from 49 tuberculosis suspects were analyzed.
• Direct smears were stained immediately using the hot Ziehl-Neelsen (ZN) method.
• Sputum samples were preserved in phenol ammonium sulphate basic fuchsin solution for seven days before preparing pot smears.

Main Results:

• The pot-method demonstrated high agreement with the ZN method (kappa = 0.87).
• Sensitivity and specificity of the pot-method were 96.8% and 91.7%, respectively.
• The pot-method correctly identified AFB in 61 of 63 smear-positive and 11 of 12 smear-negative patients.

Conclusions:

• Sputum samples can be effectively stored for up to seven days in phenol ammonium sulphate basic fuchsin solution.
• The pot-method shows promise as an alternative for sputum sample storage and transportation for AFB detection.
• Further comprehensive studies are recommended to validate the pot-method's accuracy in routine diagnostic settings.