September 3, 2009
In a new study, scientists in Iran report "the emergence of new forms of resistant bacilli (totally drug-resistant [TDR] or super extensively drug-resistant [XDR] tuberculosis [TB] strains) among patients with multidrug-resistant TB (MDR-TB)."
"Of 146 MDR-TB strains, eight XDR isolates (5.4 percent) and 15 TDR isolates (10.3 percent) were identified," according to Dr. Ali Akbar Velayati from Shahid Beheshti University in Tehran and colleagues. "The XDR or TDR strains were collected from both immigrants (Afghan, 30.4 percent; Azerbaijani, 8.6 percent; Iraqi, 4.3 percent) and Iranian (56.5 percent) MDR-TB cases," the authors wrote.
"In such cases, the smear and cultures remained positive after 18 months of medium treatment with second-line drugs (ethionamide, para-aminosalicylic acid, cycloserine, ofloxacin, amikacin and ciprofloxacin)," the team wrote. "Spoliogotyping revealed Haarlem (39.1 percent), Beijing (21.7 percent) EAI (21.7 percent) and CAS (17.3 percent) superfamilies of M tuberculosis."
"The isolation of TDR strains from MDR-TB patients from different regional countries is alarming and underlines the possible dissemination of such strains in Asian countries," the authors concluded. "Now the next question is how one should control and treat such cases."
In an editorial, Dr. Neil W. Schluger from Columbia University College of Physicians and Surgeons in New York City cataloged the obstacles to fighting "this challenging and often deadly form of the disease," which include the failure to medicate under supervision, nosocomial spread, the use of ineffective treatments, the unavailability of reliable rapid testing for drug susceptibility, the lack of a reliable supply of second-line treatments and the lack of new drugs. "The urgency of the situation demands our attention, our energy, and our scientific and economic resources," Schluger wrote.
The study, "Emergence of New Forms of Totally Drug-Resistant Tuberculosis Bacilli: Super Extensively Drug-Resistant Tuberculosis or Totally Drug-Resistant Strains in Iran," and the editorial, "Drug-Resistant Tuberculosis: What Is to Be Done?" were published in Chest (2009;136(2):420-425 and 333-335).