Browsing by Author "Lucchi, N.W."
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Item A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs(2013-12-17) Quashie, N.B.; Duah, N.O.; Abuaku, B.; Quaye, L.; Ayanful-Torgby, R.; Akwoviah, G.A.; Kweku, M.; Johnson, J.D.; Lucchi, N.W.; Udhayakumar, V.; Duplessis, C.; Kronmann, K.C.; Koram, K.A.Abstract Background Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. Methods A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator. Results Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy, significant elevation of artesunate IC50 value was observed. The results also suggest the existence of possible cross-resistance among some of the test drugs. Conclusion Ghanaian P. falciparum isolates, to some extent, have become susceptible to chloroquine in vitro, however the increasing trend in artesunate IC50 value observed should be of concern. Continuous monitoring of ACT in Ghana is recommended.Item Intermittent preventive treatment with sulfadoxine-pyrimethamine against malaria and anemia in pregnant women(American Journal of Tropical Medicine and Hygiene, 2011-07) Wilson, N.O.; Ceesay, F.K.; Obed, S.A.; Adjei, A.A.; Gyasi, R.K.; Rodney, P.; Ndjakani, Y.; Anderson, W.A.; Lucchi, N.W.; Stiles, J.K.The effectiveness of intermittent preventive treatment during pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) against malaria and anemia is unclear because of the spread of SP-resistant Plasmodium falciparum. This study evaluates the effectiveness of IPTp-SP among pregnant women attending the antenatal clinic at Korle-Bu Teaching Hospital in Accra, Ghana. A cross-sectional study comparing malaria and anemia prevalence among pregnant women using IPTp-SP with non-IPTp-SP users was conducted during June-August 2009. A total of 363 pregnant women (202 of IPTp users and 161 non-IPTp users) were recruited. A total of 15.3% of IPTp users had malaria compared with 44.7% of non-IPTp users (P < 0.001). A total of 58.4% of non-IPTp users were anemic compared with 22.8% of IPTp users (P < 0.001). When we controlled for other variables, the difference in the prevalence of malaria (odds ratio = 0.18, 95% confidence interval = 0.08-0.37) and anemia (odds ratio = 0.20, 95% confidence interval = 0.12-0.34) remained significant. The recommended IPTp-SP regimen is useful in preventing malaria and anemia among pregnant women in Ghana. Copyright © 2011 by The American Society of Tropical Medicine and Hygiene.Item A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs(Malaria Journal, 2013-12) Quashie, N.B.; Duah, N.O.; Abuaku, B.; Quaye, L.; Ayanful-Torgby, R.; Akwoviah, G.A.; Kweku, M.; Johnson, J.D.; Lucchi, N.W.; Udhayakumar, V.; Duplessis, C.; Kronmann, K.C.; Koram, K.A.Background: Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy. Methods. A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC§ssub§50§esub§) for each drug was estimated using the online program, ICEstimator. Results: Pooled results from all the sentinel sites indicated geometric mean IC§ssub§50§esub§ values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC§ssub§ 50§esub§ value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy, significant elevation of artesunate IC§ssub§50§esub§ value was observed. The results also suggest the existence of possible cross-resistance among some of the test drugs. Conclusion: Ghanaian P. falciparum isolates, to some extent, have become susceptible to chloroquine in vitro, however the increasing trend in artesunate IC§ssub§50§esub§ value observed should be of concern. Continuous monitoring of ACT in Ghana is recommended. © 2013 Quashie et al.; licensee BioMed Central Ltd.