Tuberculosis refers to a bacterial infection that affects the lungs, and its mode of transmission is via air droplets released during coughing, spitting, sneezing, or talking. Dormant TB germs affect one out of every three in a population worldwide and when the bacteria are active that is when we say that someone is ill with TB. Furthermore, XDR-TB affects people whose immunity is low or who have respiratory problems. A healthy and normal person is only infected with TB when he/she is exposed to the bacteria.
Extensive drug-resistant TB (XDR-TB) can be defined as a multi-drug resistant TB that offers resistance to three or more of the six classes of second-line injectable drugs which include amikacin, capreomycin, and kanamycin. The description of XDR-TB was coined in late 2005 and used for the first time in early 2006, due to a joint survey conducted by WHO and the Centers for Disease Control in the US. The main cause of resistance to anti-TB drugs is poorly managed TB care which encompasses an erratic supply of drugs or poor quality drugs, incorrect prescription of drugs by providers, and non-adherence by patients.
More recent findings as shown in a survey jointly conducted by WHO and CDC from 2000 – 2004 revealed that XDR-TB is present in all regions of the world but is most common in the countries of the former Soviet Union and Asia. According to those statistics, 4% Multi-Drug Resistant (MDR-TB) cases met the criteria for XDR-TB while in Latvia a similar situation was represented by 19%. Other data concerning a recent outbreak of XDR-TB in an HIV-positive population in Kwazulu – Natal in South Africa reported very high mortality rates. 544 patients formed the subject of study of which 221 had MDR-TB.
Of these MDR-TB cases, 53 were positively identified as XDR-TB. Out of the 53 patients, 44 of them were tested for HIV and all turned out to be HIV-Positive. Among the 53 patients, 52 of them died on an approximated average of within 25 days in addition to those who were placed under antiretroviral drugs. On the other hand, data collected from Africa regarding drug resistance demonstrate that the population prevalence of drug resistant TB is relatively lower than in Eastern Europe and Asia, even though drug resistance in the region is on the rise.
XDR-TB, therefore, poses a great public health threat more so in populations where HIV is prevalent and where health care resources are in short supply. An alternative way to cure XDR-TB, therefore, is by preventing it. In doing so, the disease can easily be reduced and eventually eliminated. WHO recommends several preventive precautions for the disease which include: Strengthening basic TB care to avoid the emergence of drug resistance, the diagnosis, and treatment of drug-resistant cases should be done promptly to cure existing cases and prevent further transmission of the disease, there should be an increased group effort between TB and HIV control programs so that co-infected patients can receive necessary prevention and care; there should be more investment made in laboratory infrastructures to ensure better recognition and management of the prevalence of resistant cases.
The epidemiology and the partial genotypic data currently available indicate that this is not a single strain, but rather expansively drug-resistant strains are prone to have emerged in many different places and on multiple instances. Ironically, this is both comforting and alarming. It is encouraging because the surfacing of extensively drug-resistant tuberculosis in manifold strains suggests that the mutations responsible are specific for drug resistance rather than reflecting an indispensable change in the behavior of the organism. On the other hand, it is disturbing because it also suggests that extensively drug-resistant tuberculosis probably arises fairly frequently and is already scattered.
Drug resistance that occurs in tuberculosis is a result of poorly managed care and the means used to control the disease. Bad prescription practices, low drug quality, and low adherence by the patient can all contribute to this. Bacilli are exposed to a high drug range and exposure to mono-therapy manipulates the growth of mutations that give resistance. In such a case the optimal management includes four drugs to which the organism is sensitive; where a single drug should never form part of a failing regimen.
Routine culture and compassion testing are still not obtainable in most parts of the world. In a situation where multidrug-resistant tuberculosis surfaces, unsuitable treatment regimens may lead to serial attainment of resistance mutations, with the ability to bring into view extensively drug-resistant tuberculosis. The use of second-line tuberculosis drugs which include quinolones for respiratory tract infections may also donate to the development of resistance. Therefore, the emergence of extensively drug-resistant tuberculosis should not bring with it any surprise—this was entirely expected in the context of poor control practices.
The symptoms of TB disease are quite general and those of XDR-TB are similar to those of ordinary or drug-susceptible TB. They comprise profuse sweating at night, loss of weight, feelings of weakness, fever, having a cough with thick cloudy mucus or sputum for more than two weeks, chest pain accompanied by shortness of breath, and coughing up of blood.
Treatment of XDR is possible in some cases: when TB control programs are effectively applied. The control programs have shown that cure is possible for up to 30% of affected people. That the outcome will be successful is highly dependent on the extent to which the disease is drug-resistant, how frail the immune system of the patient is and how severe the disease is.
Prevention of XDR-TB should be approached from different perspectives which include the patients and health care providers and this is because the spread of XDR –TB depends on the precautions taken by these two groups of people. In an attempt to prevent the disease, health care providers should take into consideration several factors which include quick diagnosis of cases, following the recommended guidelines of treatment, keeping an eye on patients’ response to treatment, and ensuring that therapy is concluded. Patients on the other hand should follow the given instructions of medication.
Countries also play a very crucial role in preventing XDR-TB. This is met by making sure that the effort of their national programs for keeping TB in check is carried out according to the international standards for TB care. This includes the provision of proper diagnosis and treatment to all TB patients without any costs, assuring timely and regular supplies of all anti-TB drugs and offering patients the support that they need to maximize adherence to prescribed routines, looking after XDR-TB cases in a place that is appropriately ventilated and separating them from other patients more so those with HIV, especially in the premature stages.
Division of Tuberculosis Elimination. Web.
The emergence of XDR TB on 2008. Web.
Extensively drug-resistant tuberculosis on 2008. Web.
Shah NS, Wright A, Bai G-H, Barrera L, Boulahbal F, Martín-Casabona N, et al. Worldwide emergence of extensively drug-resistant tuberculosis. Web.
World Health Organization: Emergence of XDR-TB. WHO concern over extensive drug-resistant TB strains that are virtually untreatable. Web.