Resistance to Second-Line TB Drugs Rises

To be truly effective, tuberculosis treatment guidelines should reflect every country’s unique patterns of transmissibility and drug resistance, Sven Hoffner, Ph.D., wrote in an accompanying editorial (Lancet 2012 Aug. 30 [http://dx.doi.org/10.1016/ S0140-6736(12)61069-1]).

"Dalton and colleagues’ study increases awareness of the clinical and public health issues caused by resistant M. tuberculosis and reveals differences in prevalence and risk factors between countries and settings," wrote Dr. Hoffner of the Swedish Institute for Communicable Disease Control. "Hopefully, these findings will contribute to the identification of the tools needed for optimum control of multidrug-resistant tuberculosis in specific epidemiological settings."

While prior tuberculosis treatment remains the biggest risk factor for resistant infections, other risks vary widely among countries, depending not only on local sociodemographic factors, but also on a global inability to quantify strains that have become extensively drug resistant.

"These results show that extensively drug-resistant tuberculosis is high. Nevertheless, the information remains insufficient to give a clear view of the worldwide distributions and true magnitude of XDR tuberculosis, even more so for the most severely resistant cases," Dr. Hoffner noted. "Updated information on multidrug-resistant tuberculosis and investigation of the trends are urgently needed, especially since the true scale of the burden of multi- and extensively-resistant tuberculosis might be underestimated and seems to be rapidly increasing."

Dr. Hoffner is chief microbiologist at the Swedish Institute for Communicable Disease Control, Solna. He had no financial disclosures.