Tuberculosis

Tuberculosis:


•One person is infected with Tuberculosis (TB) 

every second.

•

•There are an estimated 4,400 deaths per 

day caused by TB.

•

•It is estimated that 2 million deaths resulted 

from TB in 2012.

•One-third of the world’s population, or 

approximately

  

2 billion people, is currently infected with TB.

•

•5-10% of the people infected with TB will 

develop the active stage of the disease 

becoming infectious during their life.

•Left untreated, each person with active TB 

will infect on average between 10 and 15 

individuals every year

Morphology of Mycobacteria.

•slender,

•curved,

•nonmotile,

•nonsporing rods

•often are beaded or banded, coccoid or 

filamentous.

•They may produce L-forms.

•

•They are acid fast and

resistant to acids, alkalis,

and dehydration.

Sites of infection

•Lungs – primary site, > 80% of infections

•CNS

•Lymphatic system

•Genitourinary tract

•Gastrointestinal tract

•Bones and joints

•Disseminated (milliary TB)

Diagnosis

•Clinical specimens: sputum, bronchial or gastric washings, pleural fluid, urine, or cerebrospinal fluid.

1. Microscopy: detection of acid-fast bacilli via the Ziehl-Neelsen method.

2. Bacteriological method.

–M. tuberculosis can be differentiated from most other mycobacteria by the production of niacin.

3. PCR.

4. Tuberculin skin test.

Treatment

•First line: isoniazid, rifampin, pyrazinamide, ethambutol, streptomycin (injectables only)

•Second line : cycloserine, kanamycin, capreomycin, rifabutin, fluoroquinolones (levofloxacin), viomycin, clarithromycin,

  azithromycin