Correlation between DRMs and virus subtypes
There were 547 (34.3%) subtype B, 117 (35.2%) CRF01_AE, 19 (33.9%) CRF02_AG, 26 (49.1%) subtype A, 2 (8.3%) CRF56_cpx, 7 (36.8%) subtype C, 4 (33.3%) CRF07_BC, and 9 (56.3%) other subtypes in the study cohort. Overall, 731 (34.7%) HIV-1 pol sequences with one or more DRMs were detected. High-level DRM was detected in 12.3% (259/2107) of patients. The DRM profile differed in CRF01_AE, CRF02_AG, and subtype A. The proportion of six mutations, A62V (NRTI), K219E/Q/N/R (NRTI), E138A/G/K (NNRTI), V179F/D/E (NNRTI), Y181C/V/I/F (NNRTI), and Y188C/L/H (NNRTI), differed significantly among sub-types (P < 0.05; Table 1). The percentage of the NRTI mutation A62V was high in subtype A (32.1%) and low in subtype B (0.7%). NRTI mutations K219E/Q/N/R were observed frequently in CRF01_AE (2.4%) and CRF02_AG (5.4%), compared with that in the study cohort (1.1%). Moreover, NNRTI mutations, E138A/G/K (10.7%) and Y181C/V/I/F (7.1%), were observed frequently in CRF02_AG. In contrast, the PI mutation, M46I/L, was observed only in subtype B (0.9%) and CRF01_AE (0.6%). The most frequent DRM in all subtypes was V179F/D/E (11.1%).