**Infection for** *Mycobacterium tuberculosis* **and Nontuberculous Mycobacteria in the HIV/AIDS Patients**

Lilian María Mederos Cuervo

*National Reference Laboratory TB/Mycobacteria Collaborate Center PAHO / WHO Tropical Medicine Institute Pedro Kourí (IPK) Cuba* 

## **1. Introduction**

Tuberculosis (TB) is a disease also know as consumption, wasting disease, and the white plague, it has affected humans for centuries. Until the mid-1800s, people thought that tuberculosis, or TB, was hereditary. They did not realize that it could be spread from person to person through the air. Also, until the 1940s and 1950s there was no cure for TB. For many people, a diagnosis of TB was a slow death sentence 1-4.

In 1865 a French surgeon, Jean-Antoine Villemin, proved that TB was contagious, and in 1882 a german scientist named Robert Koch discovered the bacteria causes TB, denominated as *Mycobacterium tuberculosis*. Yet half a century passed before drugs were discovered that could cure TB, until then, many people with TB were sent to sanatoriums, special rest homes where they followed a prescribed routine every day. A breakthrough came in 1943, an american scientist, Selman Waksman discovered a drug that could kill TB bacteria. Between 1943 and 1952, two more drugs were found, after these discoveries, many people with TB were cured and the death rate for TB in the United States dropped dramatically, and fewer and fewer people got TB 5.

A global health emergency 6, 7:


TB program activities, reinforced by successful chemotherapy, resulted in a pronounced reduction of infection and death rates. The disease became greatly controlled but it never quite disappeared. Then, in around 1985, cases of TB began to rise again in industrialized countries. Several inter-related forces drove this resurgence, including increase in prison populations, homelessness, injection drug use, crowded housing and increased immigration from countries where TB continued to be endemic. Above all, the decline in TB control activities and the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic were two major factors fuelling each other in the re-emergence of TB. People with HIV and TB infection are much more likely to develop TB. The HIV/AIDS epidemic has produced a devastating effect on TB control worldwide. While one out of ten

Infection for *Mycobacterium tuberculosis* and

will develop at some point 5-7.

by pulmonary TB 3, 8, 16-23**.** 

**4. Epidemiology of TB** 

Nontuberculous Mycobacteria in the HIV/AIDS Patients 5

when the macrophages die. These bacilli can spread through the lymphatic channels to regional lymph nodes and then through the bloodstream to more distant tissues and organs, including areas in which TB disease is most likely to develop: the apices of the lung, the kidneys, the brain, and bone. Extracellular bacilli attract macrophages form the bloodstream. The immune response kills most of the bacilli, leading to the formation of a granuloma. At this point the person has TB infection, which can be detected by using the tuberculin skin test. It may take 2-10 weeks for the infected person to develop a positive reaction to the tuberculin skin test. Immune responses soon develop to kill the bacilli. Within 2-10 weeks after infection, the immune system is usually able to halt the

In persons infected with *Mycobacterium tuberculosis* but that don't have TB disease cannot spread the infection to other people. TB infection in persons who does not have TB disease is not considered a case of TB and referred to as ¨latent TB infection¨. In some persons, TB bacilli overcome the defenses or the immune system and begin to multiply, resulting in the progression from TB infection to TB disease. This process may occur soon after or many years after infection. Some study demonstrated that approximately 5% of person who have been infected with *Mycobacterium tuberculosis* will develop TB disease in the first year or two after infection and another 5% will develop disease some time later in life. Recent infection (with the past 2 years) with *Mycobacterium tuberculosis* is therefore an important risk factor for progression to TB disease and in approximately 10% of persons with normal immune system who are infected with *Mycobacterium tuberculosis* , TB disease

Some medical conditions increase the risk that TB infection will progress to disease. Some studies suggest that the risk is mayor in inmmunosuppressed patients, for example persons with Diabetes mellitus, prolonged therapy with corticosteroids, immunosuppressive therapy, certain types of cancer, severe kidney disease, injection of illicit drugs, and

TB disease most commomly affects the lung, 73% of TB cases are exclusively pulmonary, and however, TB is a systemic disease and may also commonly occur in the following ways;as pleural effusion in the central nervous, lymphatic, or genitourinary systems, as disseminated disease (military TB). Also the infection for *Mycobacterium tuberculosis* can occur in the other body sites; in the breast, skin, or peritoneum 16,20-23. Extrapulmonary TB is more common in immunosuppressed persons and in young children; meningoencephalitis TB, lymphatic TB and military disease are particularly common in immunosuppressed persons, in some case the extrapulmonary TB is often accompanied

TB infection is one of the most common infections in the world. It is estimated that 30-60% of adults in developing countries have TB infection. Annually about 8-10 million people develop TB disease and 2-3 million people die of the disease. TB disease is the leading cause of death due to infectious disease around the world 24, 25. When the health department learns about a new case of TB, it should take steps to ensure that the person receives appropriate treatment. Is very important that the health authorities should also start a contact investigation, this means interviewing a person who has TB disease to determinate

multiplication of the tubercle bacilli, preventing further spread 4, 17-19.

infection with Human Immunodeficient Virus (HIV) 2,3,12.

immunocompetent people infected with *M. tuberculosis* will fall sick in their lifetimes, among those with HIV infection, one in ten per year will develop active TB. In developing countries, the impact of HIV infection on the TB situation, especially in the 20-35 age groups, is overwhelming. While wealthy industrialized countries with good public health care systems can be expected to keep TB under control, in much of the developing world a catastrophe awaits. In poorly developed countries, TB remains a significant threat to public health, as incidences remain high, even after the introduction of vaccination and drug treatment. The registered number of new cases of TB worldwide roughly correlates with economic conditions: highest incidences are seen in the countries of Africa, Asia, and Latin America with the lowest gross national products. Supervised treatment, including sometimes direct observation of therapy (DOT), was proposed as a means of helping patients to take their drugs regularly and complete treatment, thus achieving cure and preventing the development of drug resistance 5-7.
