sentences:  In the past 10 years TB strains have emerged in Italy, Iran, India, and South Africa which are resistant to all available first and second line TB drugs, classified as totally drug-resistant tuberculosis, though there is some controversy over this term.Increasing levels of resistance in TB strains threaten to complicate the current global public health approaches to TB control.New drugs are being developed to treat extensively resistant forms but major improvements in detection, diagnosis, and treatment will be needed.