HIV contamination of commercial PCR enzymes raises the importance of quality control of low-cost in-house genotypic HIV drug resistance tests.

BACKGROUND Low-cost in-house technologies for genotypic drug resistance testing use reagents with quality labels for research only. Here, we report on the results of PCR amplifications in negative-controls that were observed in two independent laboratories. METHODS Positive PCR amplifications of protease and reverse transcriptase fragments for genotypic drug resistance testing of HIV on dried blood and/or plasma spots were observed on negative-control samples and were analysed in detail by PCR and sequence and phylogenetic analyses to identify the origin of the PCR contamination. RESULTS Detailed analysis revealed that the RT-PCR enzymes were contaminated with an HIV-based vector commercialized by the same company. CONCLUSIONS These observations show the need to implement quality control steps that verify for the absence of HIV in new reagent batches because this can significantly compromise molecular diagnosis of HIV and genotypic drug resistance tests using in-house protocols.