Characteristics of study participants
Out of 116 participants, 25 (21.6%) were mothers who were on ART after previous PMTCT prophylaxis (Group 1- Prophylaxis plus ART group), 26 (22.4%) were pregnant HIV-positive drug-naïve participants (Group 2- Drug-Naïve group), and 65 (56.0%) were mothers who had been put directly on ART without prophylaxis as a result of low CD4 + T cell count at the time they were pregnant (Group 3- Drug-Experienced without Prophylaxis group).
The age range of the participants was 20 to 46 years with the mean ages (in years) being 33.1(±5.7), 30.7(±5.6) and 33.4(±4.7) for Group 1, Group 2 and Group 3 respectively [
28].
The study participants were at different stages of disease progression according to the WHO Clinical Staging method. For Group 1 participants (Prophylaxis plus ART group), 44% were at Stage I, 52% at Stage II, 4% at Stage III and none at Stage IV of the infection. Of the participants in Group 2 (drug-naïve group), 57.7% were at Stage I and 42.3% were at Stage II of the HIV infection with no one at Stages III and IV. With the mothers in Group 3 (drug-experienced without prophylaxis group), 18.5% were at Stage I of the infection, 36.9% at Stage II, 41.5% at Stage III and 3.1% at Stage IV of the infection.
Emergence of HIV-1 drug resistance associated mutations
The study detected drug resistance associated mutations (DRAMs) in participants from each group. Thirteen percent (15/116) of samples showed the presence of drug resistance associated mutations (DRAMs); out of 40 sequences obtained for the RT gene, 35%, (14/40) showed resistance associated mutations with the reverse transcriptase gene for both NRTIs and NNRTIs. Out of the 33 sequences successfully obtained for the PR gene, 3% (1/33) had resistance associated mutations in the protease gene for Protease Inhibitors.
Amongst the participants in the drug-naïve group 15% (4/26) had resistance associated mutations, whilst in the Prophylaxis plus ART group 32% (8/25) of participants showed resistance associated mutations and participants in the drug-experienced without prophylaxis group 5% (3/65) showed DRAMs (Table
1). The difference among the groups and the emergence of DRAMs was significant,
p < 0.05.
Table 1
Association between the study variables and the emergence of HIV-1 drug resistance
Study groups | 1 (ART with prophylaxis) | 8(32) | 17(68) | 25(21.6) | .002a |
2 (Drug-Naïve) | 4(15) | 22(85) | 26(22.4) |
3 (ART with no prophylaxis) | 3(5) | 62(95) | 65(56.0) |
Duration on art (Groups 1 & 3) | < 1 Year | 4(16.7) | 20(83.3) | 24(26.7) | .624a |
1-2 Years | 5(12.5) | 35(87.5) | 40(44.4) |
≥ 3 Years | 2(7.7) | 24(92.3) | 26(28.9) |
Who clinical staging | 1 | 9(23.7) | 29(76.3) | 38(32.8) | .113a |
2 | 4(8.3) | 44(91.7) | 48(41.4) |
3 | 2(7.1) | 26(92.9) | 28(24.1) |
4 | 0(0) | 2(100) | 2(1.7) |
Adherence | Yes | 10 (12.0) | 73 (88.0) | 83(92.2) | .560a |
No | 1 (14.3) | 6 (85.7) | 7(7.8) |
The presence of DRAMs seen in the study as a result of the association between the participant’s duration on ART, WHO clinical staging and adherence to treatment, and the emergence of such DRAMs are shown in Table
1; the difference between these parameters and DRAMs were not significant,
p > 0.05.
Major drug resistance associated mutations (DRAMs) to both the NRTIs and the NNRTIs were seen in this study, as shown in Table
2 for the three different groups in the study.
Table 2
HIV-1 Drug Resistance Associated Mutations (DRAMs) in the study participants
Art after prophylaxis (Group 1) | M184 V | K103 N,Y181C |
M41 L,M184 V, T215Y | K103 N,M230 L,A98G, |
M41 L,M184 V,T215Y | K103 N A98G, |
M41 L,M184 V,T215Y | A98G, K103 N |
M41 L,M184MV,T215Y | A98G,K103 N,M230 LM |
M41 L,M184MV,T215Y | A98G,K103 N,M230 LM |
M41 L,L74 V,T215Y | K103 N, A98G,L100IL,,M230 L |
K219KR | G190EG |
Drug naïve group (Group 2) | V75S | E138A |
NONE | A98G |
M184 V | K103 N |
L210 W | V106A |
Art without prophylaxiS (Group 3) | M184 V,Y115F,T215S | A98G |
M41 LM,D67G,K70R,K219E,T215I,M184 V | A98G |
M184 V | NONE |
For Group 1 (Prophylaxis plus ART Group) all the participants were given the same combination of ARVs as prophylaxis (AZT, 3TC and NVP) with the exception of one patient who was given only NVP as prophylaxis. The subsequent ART regimen for all Group 1 mothers was the same. There was no drug resistant associated mutation (DRAM) to Protease Inhibitors (PIs) in this group. The major drug resistance associated mutations to NRTIs seen among the Group 1 participants were M41 L, M184 V, M184MV, L74 V and T215Y with no minor drug resistant associated mutations to NRTIs in this group. The most commonly seen drug resistant associated mutations to NRTIs in this group were M184 V, T215Y and M41 L.
Major DRAMs to NNRTIs seen in the Prophylaxis plus ART Group (Group 1) were K103 N, Y181C, M230 L and L100IL and the minor DRAMs to NNRTIs seen was A98G. The most common HIV-1 drug resistance associated mutations seen with the NNRTIs were K103 N, M230 L and A98G. There were no resistance associated mutations with regards to the Protease Inhibitors (PIs) and no participants in this Group had been treated with a Protease Inhibitor.
In the drug-naïve participants group (Group 2), there were no drug resistance associated mutations with Protease Inhibitors either. However, there were four (4) participants (15%) showing DRAMs to NRTIs and NNRTIs. Two major HIV-1 drug resistance associated mutations for NRTIs, M184 V and L210 W, were seen in two of the participants with one minor DRAMs to NRTIs, V75S, seen in one patient; one patient did not have any drug resistance mutation to NRTIs. Three major DRAMs to NNRTIs were seen in 3 patients among the drug-naïve participants; these DRAMs were K103 N, V106A and E138A. One minor drug resistance associated mutation, A98G, was seen in one patient in this group [
28].
In Group 3 where participants had received ART but no Prophylaxis (drug-experienced without prophylaxis group) for prevention of mother-to-child transmission (PMTCT) of HIV, 3 patients (5%) showed drug resistance associated mutations to NRTIs, NNRTIs and PIs. Major and minor DRAMs to NRTIs, NNRTIs and PIs were seen in one patient who had been given NRTIs and a PI (Nelfinavir) initially, followed by other NRTIs and an NNRTI. The major DRAMs to NRTIs seen in this group were M184 V, Y115F, K70R, K219E and M41 LM while the minor DRAMs to NRTIs seen were T215S, T215I and D67G. There were no major DRAMs to NNRTIs in this group though the minor drug resistance mutation, A98G, was seen in two of the patients. The major DRAMs to PIs seen in the group was I84V; the minor drug resistance mutations seen were A71V, L89 V and M46MV. M184 V mutation was found to be the most common mutation among this group of mothers.
Thymidine analogue mutations (TAMs) were seen in this study; these were M41 L, K70R, L210 W, T215Y and K219E. The most common TAM seen in this study were M41 L and T215Y. These appeared in 7 (88%) out of the 8 participants with DRAMs in Group 1 which had prophylaxis followed by treatment.
Distribution of HIV-1 subtypes
All the sequences obtained were subtyped using the Stanford HIV database drug resistance programme (
www.hivdb.stanford.edu), which produced 33 (82%) CRF02_AG subtypes, 2 (5%) subtype CRF01_AE, 1 (3%) subtype A, 2 (5%) subtype B and 2 (5%) subtype G for the RT gene whilst the PR gene had 32 samples (97%) being subtype CRF02_AG and 1(3ó%) subtype A. Subtyping by phylogenetic analysis was also performed though some of the sequences for the RT gene were excluded from the phylogenetic tree-building (Fig.
1) because they were relatively shorter fragments. The Phylogenetic analyses were conducted in MEGA 6. Majority of study sequences clustered with the circulating recombinant form CRF02_AG.
Of the 8 mothers in Group 1(Prophylaxis plus ART) with HIV-1 drug resistance associated mutations, 7 (88%) were of subtype CRF02_AG and 1(13%) was of CRF01_AE. Out of the 4 mothers (15%) in Group 2 (Drug-Naïve patients) with HIV-1 drug resistance associated mutations, 3 (75%) were of subtype CRF02_AG and 1 (25%) was of subtype A. Two of the HIV-1 strains showing drug resistance associated mutations in Group 3 were of Subtype CRF02_AG and one was of Subtype B.