1 . Identify MDR-TB suspects

MDR-TB suspects are TB symptomatics with an identified risk to develop MDR-TB. To detect these patients, high-risk groups for MDR-TB based on findings from the DOTS-Plus pilot project and the nationwide drug resistance survey (DRS) have been identified as shown in Box 1. In general, previous anti-TB treatment is a risk factor for resistance and therefore, all previously treated patients should be referred to the MDR-TB Treatment Center for screening and diagnosis.

By asking a few basic questions to TB suspects and by correctly monitoring current TB patients, DOTS facilities will be able to detect a large number of patients with high risk for MDR-TB in a timely manner.

The symptoms of pulmonary TB are the same as for MDR-TB, in particular, cough for two weeks or more. Other symptoms of TB include fever, chest and/or back pain, hemoptysis (coughing up of blood), weight loss and others such as night sweats, fatigue, body malaise, and shortness of breath. Being a contact of an MDR-TB case puts both new and retreatment patients at high risk for MDR-TB. Experience at the Tropical Disease Foundation (TDF) showed that among 1,737 MDR-TB contacts, 251 (14%) had radiographic evidence of TB. From these, 181 who submitted sputum and had available results, 42 (23%) turned out culture-positive, with MDR noted in 24 (57.1%), drug resistance other than MDR-TB in 7 (16.7%) and pan-susceptibility in 11 (26.2%).

For retreatment cases, some patient types have higher MDR-TB prevalence than others. In the Philippines, information regarding this is still being gathered, and all retreatment cases are considered at risk of being MDR-TB. Among patients receiving DOTS Category II treatment, MDR-TB is suspected if there is non sputum smear-conversion on the third month of treatment. A limited study from the TDF DOTS-Plus pilot project showed that of 22 Category II non-converters among 226 enrolled patients, MDR-TB was noted in 73% (16). On the other hand, of 36 Category I non-converters on month 2 among 181 enrolled cases, MDR-TB was noted in only 6%.

Additionally, if a patient presents to a DOTS facility with TB and reports that he has already received two or more courses of anti-TB treatment that were self-administered upon prescription of a doctor, that patient should be suspected of having MDR-TB and be referred to an MDR-TB Treatment Center. A treatment course is defined as at least a month of intake of anti-TB drug(s) excluding prophylactic treatment.

While HIV is not by itself a risk factor for MDR-TB, since TB/HIV coinfected patients usually have negative sputum smear results, HIV-positive individuals who have TB symptoms should be investigated for resistance using culture and DST. Furthermore, HIV co-infection with MDR-TB is a severe disease with a very high mortality rate and should be diagnosed promptly for immediate treatment.

Without proper detection and treatment of persons who are at high risk for DR-TB, there is a great danger that DR-TB will continue to spread in the community.

The following table describes the high-risk groups for MDR-TB.

BOX 1: High-risk groups for MDR-tB

A . Retreatment cases

1.

2.

3. Failure

a patient who remains (or becomes) smear-positive on the 5th month or later of DOTS Category II treatment or who remains sputum-positive at the end of a retreatment regimen

Category I failure: a patient who remains (or becomes) sputum smear-positive on the 5th month or later of DOTS Category I treatment

Category II failure (chronic TB case):

Relapse of category I or II: a patient who has been declared cured or treatment completed, and is diagnosed with bacteriologically (smear or culture) positive TB

Return after default: a patient who returns to treatment with positive bacteriology (smear or culture) following interruption of treatment for two months or more 4. “Other” type of patient: a patient with one month or more of anti-TB drug intake under the DOTS strategy that cannot be classified into any type of retreatment, or a patient with one month or more of non-DOTS treatment. a) Non-DOTS patient whether sputum-positive or sputum-negative b) “Other-positive”: a sputum-positive patient with one month or more of DOTS treatment who cannot be typed as Treatment failure, Relapse, or Return after default. For example, a patient who is smear-negative initially then turned out to be positive at sputum follow-up during DOTS treatment . c) “Other negative:” a sputum-negative patient with one month or more of DOTS treatment who cannot be typed as Treatment failure, Relapse, or Return after default. For example, a patient who returns to TB treatment with negative bacteriology (smear or culture) following interruption of treatment for two months or more *A treatment course is defined as at least a month of intake of anti-TB drug(s) excluding primary and prophylactic treatment.

5. Non-converter of Category II:

a patient who remains smear-positive at the end of the third month of

DOTS Category II treatment

B . New or retreatment cases

6.

7.

Symptomatic contact of a confirmed or suspected drug-resistant patient: A “contact” refers to a household contact who is a person who normally sleeps in the same dwelling unit as the drug-resistant index case for at least three months and has a common arrangement for preparation and consumption of food. This patient has a higher risk of contracting the drug-resistant strain of the index case.

HIV-positive patient who has pulmonary or extra-pulmonary TB symptoms or has chest x-ray findings suggestive of TB: HIV infection by itself is not a risk factor specifically for MDR-TB, but for TB, in general. Since HIV-infected patients with MDR-TB have high mortality, early diagnosis through culture and DST are recommended.