We have analyzed the in vitro chemosensitivity profiles of 115 Kenyan isolates for chloroquine (CQ), piperaquine, lumefantrine (LM), and dihydroartemisinin in association with polymorphisms in pfcrt at codon 76 and pfmdr1 at codon 86, as well as with variations of the copy number of pfmdr1. The median drug concentrations that inhibit 50% of parasite growth (IC 50 s) were 41 nM (interquartile range [IQR], 18 to 73 nM), 50 nM (IQR, 29 to 96 nM), 32 nM (IQR, 17 to 46 nM), and 2 nM (IQR, 1 to 3 nM) for CQ, LM, piperaquine, and dihydroartemisinin, respectively. The activity of CQ correlated inversely with that of LM (r 2 ‫؍‬ ؊0.26; P ‫؍‬ 0.02). Interestingly, parasites for which LM IC 50 s were higher were wild type for pfcrt-76 and pfmdr1-86. All isolates had one pfmdr1 copy. Thus, the decrease in LM activity is associated with the selection of wild-type pfcrt-76 and pfmdr1-86 parasites, a feature that accounts for the inverse relationship between CQ and LM. Therefore, the use of LM-artemether is likely to lead to the selection of more CQ-susceptible parasites.Chemotherapy is still the main approach for the control of malaria, and current strategies for malaria treatment rely on the use of combinations of drugs that include artemisinin compounds. Although this strategy is designed to reduce the chance of resistance emerging, there is considerable concern that this will inevitably occur.For instance, the combination of lumefantrine (LM) and artemether (ATM), known as Coartem, has become the firstline treatment for malaria in many African countries, including Kenya (19). ATM is converted in vivo to dihydroartemisinin (DHA). Emerging reports indicate that the use of LM (in Coartem) selects for parasites that show increased tolerance to Coartem, and these parasites select for a wild-type pfmdr1 genotype or show increased copy numbers of pfmdr1, a gene associated with chloroquine (CQ) and mefloquine (MFQ) resistance (7,13,15,20,36,38). Thus, there is concern that resistance to LM could emerge rapidly. On the other hand, recent reports from Southeast Asia indicate that resistance to artemisinin derivatives is increasing, threatening the concept of artemisinin-based combinations (8).Another combination, piperaquine (PQ) and DHA, known as Artekin, is undergoing clinical evaluation (17,39,42). This drug is efficacious, safe, and affordable and thus is likely to become an alternative to Coartem. PQ is a bisquinoline derivative consisting of two linked CQ molecules. Although reports indicate that PQ retains potency against CQ-resistant parasites (3), there is concern that PQ could become less susceptible against a backdrop of high CQ resistance (17,22).In this paper, we sought to analyze the in vitro activities of the antimalarials LM, DHA, and PQ in relation to polymorphisms in pfcrt at codon 76 (pfcrt-76) and in pfmdr1 at codon 86 (pfmdr1-86) and in relation to pfmdr1 copy number variations in Kenyan isolates. We used CQ as a reference drug. MATERIALS AND METHODSCQ was purchased from Sigma Chemical Co. (Poole, Dorset, United...

BACKGROUND: Hospitalized children in sub‐Saharan Africa frequently receive whole blood transfusions for severe anemia. The risk from bacterial contamination of blood for transfusion in sub‐Saharan Africa is not known. This study assessed the frequency of bacterial contamination of pediatric whole blood transfusions at a referral hospital in Kenya. STUDY DESIGN AND METHODS: This was an observational study. Over the course of 1 year, bacteriologic cultures were performed on 434 of the 799 blood packs issued to children by the blood bank of Coast Provincial General Hospital, Mombasa. Clinical outcome was not assessed. RESULTS: Forty‐four bacterial contaminants were isolated from 38 blood packs—an overall contamination frequency of 8.8% (95% confidence interval, 6.1%‐11.4%). Sixty‐four percent of the bacteria isolated were Gram‐negative. Many of the isolates are usually found in the environment and the most likely source of contamination was considered to be the hospital blood bank. CONCLUSION: Bacterial contamination of whole blood may be a significant but unrecognized hazard of blood transfusion for children in sub‐Saharan Africa. Further work is needed to clarify the extent of the problem and its clinical consequences. Increased awareness and adherence to basic principles of asepsis in the hospital blood bank may be important immediate interventions.