Name: PEDRO SOUSA DE ALMEIDA JUNIOR
Type: PhD thesis
Publication date: 16/08/2019
Advisor:
Name |
Role |
|---|---|
| MOISES PALACI | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| FABÍOLA KARLA CORRÊA RIBEIRO | External Examiner * |
| KÊNIA VALÉRIA DOS SANTOS | Internal Examiner * |
| LILIANA CRUZ SPANO | Internal Examiner * |
| MOISES PALACI | Advisor * |
Summary: Tuberculosis (TB) is one of the oldest infectious-contagious diseases in the world and the eradication of which remains a challenge. One of the major problems related to TB is the latent infection in which Mycobacterium tuberculosis (MTB) is found in its host in a metabolic state characterized as "numbness". In this state, the microorganism is not recognized by the immune system and is not detected by conventional diagnostic methods. This work aims to detect metabolically diverse populations of MTB in sputum samples of patients with pulmonary TB and to analyse the influence of tuberculosis therapy on these bacilli. The secondary objective of this study is to verify whether persistent bacilli populations may imply therapeutic failure. For this purpose, the 48 wells plate dilution technique was used, which determines the amount of microorganisms by calculating the Most Probable Number (MPN). The MPN determines the amount of microorganisms that grow in liquid medium (7H 9) and in liquid medium after the addition of liquid culture supernatant of MTB (SN). In addition, conventional diagnostic methods, bacilloscopy and solid and liquid cultures were performed. Sputum samples were collected prior to treatment (M0) and monthly until the end of treatment (M1 to M6). To lower the rate of contamination during the procedure, oral hygiene with chlorhexidine 0.12% was standardized. The preliminary clinical and epidemiological data show that the population studied is young (39.6 ± 19.4), with body mass index (BMI) within the international standards of normality (20.5 ± 1.6), being 57% male patients and 43% female. The most reported symptoms were cough and fever, with time of disease progression around 1 to 3 months as the most frequent period (71% for each). The preliminary radiographic data indicate that all patients had radiographic images suggestive of abnormal TB, with six (86%) of these patients characterized with advanced disease and one (14%) with moderate, with the same proportion found in relation to cavitation. The microbiological data reveal that only one (20%) of the conventional cultures (Ogawa or MGIT) remained positive for MTB after two months of treatment. A preliminary analysis indicated that 84% of the bacilli of the samples M0 and 98% of the M1-M4 samples are dormant or SN-dependent bacilli. When analysing the effect of TB therapy on the different MTB populations in sputum samples of patients under treatment, a progressive decrease in the amount of microorganisms over the months of treatment was observed, mainly in relation to metabolically active microorganisms.
