Acid-fast bacilli (AFB) smear and mycobacterium tuberculosis (MTB) culture

The 2022 update of the Practical Manual on Tuberculosis Laboratory Strengthening by the World Health Organization (WHO) outlines the meticulous adherence to laboratory protocols for tuberculosis testing [29]. Acid-fast staining microscopy includes the preparation of a smear from a patient’s sample, staining it with a dye (such as Auramine O), heating the smear, and subsequently examining it under a microscope to detect the presence of mycobacteria. 1. Utilizing the MGIT 960 detection system, a mixture of 1 ml of cerebrospinal fluid (CSF) and 0.8 ml of Middlebrook 7H9 Broth Base for MGIT culture was prepared in the MGIT tube. The tube was then placed in a 37 °C BACTEC MGIT 960 system (Becton Dickinson; Franklin Lakes, NJ, USA) for incubation. To address the challenge of prolonged detection cycles in the cultivation process, we have decided to extend the cultivation period of Mycobacterium tuberculosis (MTB) negative MGIT tubes by an additional eight weeks to improve the detection rate of MTB. This strategy is particularly crucial for patients suspected of having intracranial tuberculosis, as they may exhibit lower levels of Mycobacterium tuberculosis. By increasing the culture duration, we could enhance the likelihood of detecting MTB, resulting in more accurate diagnostic outcomes for patients.