Abstract:
Tanzania is among the countries in Sub-Saharan Africa with high prevalence of HIV
infection. The country has implemented several interventions for control and prevention,
including care and treatment with ARV drugs. The ARV drug treatment programme of
patients living with HIV and AIDS started in 2004. Among the major potential challenges
inherent in ARV drug treatment programmes is the danger of emergence of ARV drugresistant
strains. This study aimed at determining the occurrence and risk factors of ARV
drug resistance among HIV patients receiving ARV treatment at the ART clinic in Muhimbili
National Hospital, Dar es Salaam.
A descriptive comparison study selecting cases (HIV patients on ARV treatment for more
than six months experiencing treatment failure) and non-cases (HIV patients on ARV
treatment for more than six months responding well to treatment) was conducted. Viral load
testing and genotypic resistance testing was done on 150 of the patient samples (79 cases and
71 non-cases). Epi Info version 3.3.2 and Microsoft excel were used for general data analysis.
Chromas Pro, Bioedit and Mega 2 were used for Phylogenetic analysis. ARV resistant
mutations were analysed using Stanford ARV resistance database.
There was no statistically significant difference between cases and non-cases with respect to
marital status, education level, gender and mean viral load and development of ARV
resistance mutations.
The difference in mean percentage weight gain and the mean percentage CD4 increase
between cases and non-cases was statistically significant at a P-value of 0.0001. The clinical
stage of the patients at the initiation of therapy was found to be a significant factor for
development of drug failure at a P-value of 0.001.
Only 28 samples were fully sequenced and mostly those with the viral load of more than 400
copies/ml. Subtypes A and C were the most prevalent subtypes followed by subtype D and
their recombinants. Overall the occurrence of PI major mutations was 4%, PI minor mutations
was 29%, NRTI mutations 64% and NNRTI mutations 71%. The mutations detected were
related to the ARV therapy in use, more observed for Lamivudine, Stavudine and Nevirapine.
There was no significant association between subtypes and development of resistant
mutations. The maintenance of resistance genotypic programs supplied for ARV drug naïve
patients and ARV failing patients is important in the management of HIV patients
