Dawit, Assefa Arimide (2009) Prevalence of Primary HIV-1 Drug Resistance using Dried Blood Spot and Treatment Outcome of Highly Active Antiretroviral Theraphy in HIV-1 Infected Adults in Addis Ababa. Masters thesis, Addis Ababa University.
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Abstract
Background: Antiretroviral combination therapy is a major advance in the treatment of HIV infection. With the expansion of ART, a high proportion of treated cases can be expected to develop drug resistance, which will lead to transmission of resistant HIV strains to newly infected persons and thus monitoring the prevalence of drug resistance would be an effective strategy to monitor program effectiveness and to asses the public health impact of the roll-out of ART. The high cost and complexity of resistance testing assays make the tests almost inaccessible in resource-limited settings like Ethiopia. Beside the cost, the blood sample collection, storage and transportation remains a problem in developing countries. Dry blood spots (DBS) are an ideal medium for blood collection in the field. Dried blood spot are simpler to prepare, store and transport than plasma and serum. Since the treatment has recently become available in Ethiopia, few data are available concerning the clinical and immunological outcomes of HAART, the effect of HAART on the prognosis of opportunistic infections and common side effects of ARV drugs. Objective: To determine the prevalence of primary HIV drug resistance using dried blood spot and assess treatment outcome of HAART using clinical and immunological parameter among patients receiving ART at public health facilities in Addis Ababa. Method: The less expensive in-house assay for drug resistance testing that amplifies 1,023bp HIV-1 pol fragment (13-99 of PR and 1-254 of RT) was evaluated against the FDA-approved ViroSeqTM HIV-1 Genotyping System. A total of 46 samples were used for this evaluation. The in-house assay was validated by comparing sequence data and drug resistance profiles to data from the ViroSeqTM HIV-1 Genotyping system. DBS were prepared from blood specimens that were collected from newly diagnosed, treatment-naive HIV-positive subjects in Addis Ababa in 2005 and placed in a gas impermeable, sealable plastic bag containing a silica gel desiccant, and stored at -20°C for 40.7±5.4 months. Genotyping was done from single spot of DBS using an in-house assay that amplifies 1,023bp HIV-1 pol fragment. Sequence data and drug resistance profiles obtained from DBS were compared with corresponding plasma. And furthermore genotypes obtained from DBS were used to determine the level of transmitted HIV drug resistance in Addis Ababa in 20005. A retrospective analysis of clinical data from two hospitals in Addis Ababa, Ethiopia was done. A total of 547 subjects were enrolled in this study. Of these 62% of them were females. The subjects were followed for a mean of 11.4 months. Results: The mean nucleotide similarity of the pol sequence of the in-house assay and the ViroSeqTM assay was 99.35±0.5% and ranged between 98% and 100%. All major HIV drug resistance-associated mutations detected by the ViroSeqTM assay were also detected by the in-house assay. Sixty two (98.4%) of DBS specimens were successfully genotyped. The mean nucleotide similarity of the pol sequence of the paired plasma and DBS was 99.64±0.33% and ranged between 98.9% and 100%. Among these sample (n=62) one patient was found to harbour K103N mutation that cause resistant for NNRTI (NVP and EFV) and another patient was also found to harbour Y188H that cause an intermediate level resistance to NNRTI. No major HIVDR mutation related to NRTI and PIs was detected. HAART increased the median CD4 cell count from 124 cell/ μl at baseline to 237 cell/ μl after an average of 11.4 months. After this period on HAART the proportion of patient with CD4 cell count ≥ 200 cell/μl increased from 18.3% to 62.5%. Most of the opportunistic infection diagnosed after HAART were found to occur within the first 15 weeks after HAART. Conclusions: Thus based on our finding, the in-house assay showed comparable sensitivity, specificity and efficiency with the FDA approved commercial HIV drug resistance genotyping assay (ViroSeqTM) and can be used to effectively monitor patients failing ARV therapy, as well as to collect surveillance data on the emergence and transmission of HIV-1 drug resistance isolates within the population where different subtype circulates. The high nucleotide similarity between the DBS and plasma pol gene sequence suggest that the genotype obtained from DBS are equivalent to those of plasma which makes DBS as reliable alternative specimen resource to plasma for drug resistance surveillance among treatment naïve subjects in resource limited settings where logistic difficulties could prevent the use of plasma and serum for HIV drug resistance testing. The high efficiency of HIV drug resistance genotyping from DBS stored at -20°C with desiccant suggested that -20°C may be suitable for long term storage of DBS. The detection of primary HIV-1 drug resistance mutation in blood sample collected before the expansion of HAART might be due to the availability of unregulated ARV drugs in the black market before the government launched free ARV treatment initiative in 2005. Thus continued surveillance of drug resistance in treated and untreated populations is needed to prevent further transmission of HIV drug-resistant variants and maximize the efficacy of antiretroviral therapy in Ethiopia. HAART has resulted in increase in CD4+ T cell count and thus continuous efforts should be made to further expand the access to ART in Ethiopia and thereby special attention should be given to the implementation of existing preventive strategies and monitoring of these patients on treatment.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | H Social Sciences > H Social Sciences (General) Q Science > Q Science (General) R Medicine > RS Pharmacy and materia medica |
| Divisions: | Africana |
| Depositing User: | Vincent Mpoza |
| Date Deposited: | 21 Jun 2018 07:41 |
| Last Modified: | 21 Jun 2018 07:41 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/5306 |
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