Xpert ® MTB/RIF offers new and important possibilities for the diagnosis of sputum smear-negative tuberculosis (TB) and/or rifampicin (RMP) resistance, and many are encouraging rapid and widespread implementation. This simple test can be implemented almost everywhere, and it provides results within a few hours. In low-income countries (LICs), however, its cost, environmental limitations (stable and regular electricity, adequate room temperature) and difficulties involved in supply and maintenance are major obstacles. While it may be suitable for major reference hospitals, operational research is needed to evaluate the test and its additional yield above high-quality smear microscopy and clinical algorithms before its use at the peripheral level. In the meantime, direct microscopy should remain the initial diagnostic test for TB suspects. In most LICs, the prevalence of RMP resistance among new TB patients is very low; an Xpert MTB/RIF result indicating RMP resistance will thus always need confirmation by another test. In a population at high risk of RMP resistance (> 15%), however, the positive predictive value for RMP resistance by Xpert MTB/RIF is high, and identification of RMP resistance is an excellent proxy for multidrug-resistant TB (MDR-TB). The assay should be widely used for this purpose if, and only if, excellent MDR-TB management is available, both for ethical reasons and to reduce the risk of extensively drug-resistant TB.
The development and validation of dried sample spots as a method of specimen collection are urgently needed in developing countries for monitoring of human immunodeficiency virus (HIV) infection. Our aim was to test some crucial steps in the use of dried spots, i.e., viral recovery and storage over time. Moreover, we investigated whether dried plasma and blood spots (DPS and DBS, respectively) give comparable viral load (VL) results. Four manual RNA extraction methods from commercial HIV type 1 (HIV-1) VL assays-a QIAamp minikit (Qiagen), the Abbott Molecular sample preparation system, the Nuclisens assay (bioMarieux), and High Pure viral nucleic acid kit (Roche Applied Science)-were compared for VL quantification and PCR amplification for genotypic drug resistance testing on dried spots from spiked plasma and residual samples from HIV-1 patients (n ؍ 47; median VL, 4.13 log 10 copies/ml). RNA recovery from DPS was efficient using Nuclisens extraction (median difference, 0.03 log 10 copies/ml) and slightly underestimated using the Abbott Molecular sample preparation system (median difference, 0.35 log 10 copies/ml). PCR amplification results were in concordance. Measurements from DBS overestimated VL for plasma, with VL results showing <3.7 log 10 copies/ml. VL was stable for up to 3 months in spiked DPS stored at 20°C but for only 1 month at 37°C. A faster decline was observed in PCR efficiency: DPS could be stored for 1 week at 37°C and for 1 month at 20°C. In conclusion, the RNA extraction method is an important factor in obtaining reliable RNA quantification and PCR amplification of HIV-1 on DPS/DBS. DBS could be used as an alternative for DPS depending on HIV RNA cutoffs for virological failure. VL measurements remain stable over a longer period than do PCR amplification results.Due to the efforts of national programs and the support of a wide range of international partners, the number of people receiving antiretroviral therapy (ART) in resource-limited countries has increased significantly over recent years, most notably in sub-Saharan Africa (24). In order to limit the emergence of resistance to antiretroviral drugs, human immunodeficiency virus (HIV) treatment should ideally be accompanied by periodic virological monitoring, such as viral load and resistance testing. However, in resource-limited countries, viral load monitoring and drug resistance tests are not yet available at an affordable cost, and infrastructure requirements limit the scale-up in access to these tests. Treatment initiation and modifications are thus guided mainly by clinical disease progression and by CD4 cell counts, when possible (13, 24). As a consequence, many people with virological failure stay on inadequate drug regimens for long periods. Rapid or uncontrolled emergence of HIV drug resistance is thus feared as a potential consequence of ART scale-up in resource-limited countries. Therefore, ART resistance monitoring is not recommended at the individual patient level in low-income countries, and the WHO has established a sys...
Virological monitoring is still feasible for DBS after 3 months of storage at 37 degrees C when VL is >5000 copies/mL, but DNA contributes largely to the final results.
The accumulation of drug resistance mutations with time on ART needs further attention, and surveillance should be reinforced in ART programs in sub-Saharan Africa.
Molecular epidemiological studies revealed that the epicenter of the HIV pandemic was Kinshasa, the capital city of the Democratic Republic of the Congo (DRC) in Central Africa. All known subtypes and numerous complex recombinant strains co-circulate in the DRC. Moreover, high intra-subtype diversity has been also documented. During two previous surveys on HIV-1 antiretroviral drug resistance in the DRC, we identified two divergent subtype C lineages in the protease and partial reverse transcriptase gene regions. We sequenced eight near full-length genomes and classified them using bootscanning and likelihood-based phylogenetic analyses. Four strains are more closely related to subtype C although within the range of inter sub-subtype distances. However, these strains also have small unclassified fragments and thus were named CRF92_C2U. Another strain is a unique recombinant of CRF92_C2U with an additional small unclassified fragment and a small divergent subtype A fragment. The three remaining strains represent a complex mosaic named CRF93_cpx. CRF93_cpx have two fragments of divergent subtype C sequences, which are not conventional subtype C nor the above described C2, and multiple divergent subtype A-like fragments. We then inferred the time-scaled evolutionary history of subtype C following a Bayesian approach and a partitioned analysis using major genomic regions. CRF92_C2U and CRF93_cpx had the most recent common ancestor with conventional subtype C around 1932 and 1928, respectively. A Bayesian demographic reconstruction corroborated that the subtype C transition to a faster phase of exponential growth occurred during the 1950s. Our analysis showed considerable differences between the newly discovered early-divergent strains and the conventional subtype C and therefore suggested that this virus has been diverging in humans for several decades before the HIV/M diversity boom in the 1950s.
Purpose The decision to amputate is always difficult but becomes even harder in emergency situations, which usually present extra complicating factors. MSF Experience These include human factors (related to both the surgeon and the patient); poor or nonexistent medical facilities, especially in war conditions or resource-poor countries; and cultural and religious considerations. Médecins Sans Frontières (MSF) has developed a quick medical and logistical response that relies on surgical protocols adapted to emergency situations, together with complete "kits" of medical equipment, supplies and inflatable facilities. Conclusion Our response to Haiti's 2010 earthquake relied on these tools but also highlighted the need to develop more detailed protocols that will help our teams on the ground.
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