Researchers in Australia have discovered that 12% of HIV-positive individuals receiving treatment are infected with a strain resistant to antiretroviral medication. This N348I mutation confers resistance to AZT and nevirapine. Typically physicians perform genotypic assays to look for mutations of a patient's particular strain of HIV and then, from these results, prescribes a cocktail that is least likely to become resistant to the medication. Previously these genotypic assays have focused on the N-terminal region of the reverse transcriptase, since that is where a majority of the drug-resistance mutations have occurred. However, this group of researchers decided to investigate the C terminus of the enzyme and found the N348I mutation. As a result of these findings, health care practitioners will likely add this mutation to their assay test. Moreover, since this mutation was found in 12% of HIV-positive individuals receiving treatment versus only 1% of HIV-positive people not on these medications, further investigation of the N348I mutation carries important implications for future antiretroviral drug development.