Browsing by Author "Sackey, S.T."

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Assessment of bacterial diversity in western Accra, Ghana, drinking water samples
(Journal of Water, Sanitation and Hygiene for Development, 2019) Ecklu-Mensah, G.; Sackey, S.T.; Morrison, H.G.; et.al
The design and performance characteristics of municipal drinking water systems can profoundly influence public health. To assess the operational attributes of an Accra, Ghana drinking water distribution system, high-throughput 454 pyrosequencing was employed to characterize its bacterial community composition. Samples from the waterworks and four household sources (one household tap and three polytank storage units) were analyzed within one of Accra’s distribution networks over 4 months. Samples provided between 9,059 and 20,076 reads (average ¼ 13,056) that represented a broad range of bacterial diversity, including rare genera. Minimum Entropy Decomposition (MED) analysis showed that the sequences described four major assemblages. Assemblages 1 and 2 dominated the waterworks and household tap samples while polytank storage unit samples, with one exception, contained assemblages 3 or 4. The considerable bacterial taxonomic difference between different sources suggests that contamination and/or selective growth shapes bacterial community structures after treatment at the waterworks. Of particular interest are the major differences between the poly tank samples following storage and the tap/waterworks samples, suggesting that water storage (stagnation) can select for unique microbial populations
Diagnosis of Cocoa Swollen Shoot Virus Disease by Polymerase Chain Reaction (PCR)
(University of Ghana, 2000-12) Osei, R.N.D.; Sackey, S.T.; Osei, Y.D.; University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Biochemistry, Cell and Molecular Biology
Cocoa swollen shoot virus disease causes severe damage to cocoa farms leading to substantial losses in crop yield and therefore the country’s revenue from cocoa. This study set out to design new PCR primers for the detection of the virus that causes the disease. Thirty-six cocoa swollen shoot virus (CSSV) isolates, randomly selected from 5 main groups based on serological and biological properties from the CRIG museum at Tafo were used Viral DNA extracted and purified from the infected leaves were used for PCR using two sets of universal badna primers 2+T and 3+T. The multiple amplification bands produced were cut out, gel purified and hybridised against full length cloned PCR DNA of CSSV New Juaben probes to detect the amplification products of virus origin. These were then cloned, sequenced and new primers designed based on consensus sequences derived from the alignment of the CSSV sequences with sequences from other closely related badna viruses. The new pair of primers (badna primers 1+4) gave a single PCR amplification product of 600 base pairs. The thirty-six CSSV isolates from the CRIG museum were screened with the new primers to test the efficacy of these new primers. Out of the 36 isolates screened, 28 gave the expected amplification product and 8 did not give any amplification products. The new primers in comparison with the old primers can be said to be better at detecting CSSV.
Drug Resistance Mutations in HIV Patients on Antiretroviral Therapy in Ghana
(University of Ghana, 2013-06) Bonney, E.Y.A.; Sackey, S.T.; Ampofo, W.K.; Nyarko, A.K.
Highly active antiretroviral therapy (HAART) is known to improve treatment in Human Immunodeficiency Virus (HIV)-infected patients but the emergence of drug resistance is an obstacle in the effective management of HIV infection and Acquired Immune Deficiency Syndrome (AIDS). Plasma viral load monitoring is the gold standard used in high-income countries for monitoring treatment but it is not available in many resource-limited settings. Although limited viral load testing is now available in Ghana, viral load is not routinely used for monitoring majority of patients on HAART. Physicians in Ghana therefore depend mainly on CD4 counts and clinical symptoms to monitor treatment. Thus, a significant proportion of patients may suffer virologic failure while continuing to take first-line antiretroviral therapy (ART). This may encourage the development and accumulation of drug resistance mutations and compromise future treatment efforts. The aim of this study was to investigate the presence of HIV drug resistance mutations in patients on ART in Ghana, relate these mutations to treatment regimens in order to inform policy on ART monitoring and patient management in the country. Venous blood was obtained from 338 patients on ART from the Korle-Bu Teaching, St. Martin de Porres, Atua Government and Kumasi South hospitals in Ghana. Personal information and ART history of the patients were also collected using a sample collection form. The CD4 counts and viral loads of patients were determined. HIV ribonucleic acid (RNA) and proviral deoxyribonucleic acid (DNA) were extracted from the plasma and peripheral blood mononuclear cells (PBMC), respectively. The HIV protease and reverse transcriptase genes were amplified from the RNA and DNA by polymerase chain reaction. The positive amplification products were sequenced and analyzed for drug resistant mutations using the Stanford HIV Drug Resistance Database. The mean age of patients was 42 years and 72% of patients were female. The mean CD4 counts increased from 161cells/μl at start of therapy to 454cells/μl at time of sampling. Only 7% of patients had detectable viral loads at time of sampling. Most of the patients (87%) were on first-line regimen. Physicians rating showed that 86% of patients were doing well and the rest were either not doing so well (11%) or were failing (3%). The reverse transcriptase gene was successfully sequenced from 65 (19%) and 99 (29%) of plasma and PBMC respectively while protease gene was successfully sequenced from 54 (16%) of plasma and 76 (23%) of PBMC. Out of these, 46 % and 49% of the plasma sequences had nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations respectively. From PBMC, 25% and 26%, respectively had NRTI and NNRTI mutations. Protease inhibitor (PI) resistance mutations were found in 28% of plasma and 9% of PBMC sequences. The most common NRTI mutation found was M184V and that of NNRTI was K103N. Thymidine analogue mutations (TAMs) including M41L, D67N, T215Y/F, L210W and K219E/Q were mostly found in patients on second-line regimen. Protease inhibitor mutations were mainly found in patients on second-line regimen and they included M46I, V82I and N88S. Similar resistance profiles were observed in paired sequences from plasma and PBMC of the same patients. The results showed that even patients who were doing well, based on their CD4 counts, viral load and physicians assessment, were harbouring drug resistance mutations including TAMs that could render the NRTIs ineffective. The results suggest that CD4 count is an insufficient marker for monitoring treatment since it continues to increase even in the presence of drug resistance mutations. Patients on ART in Ghana may therefore not be deriving optimal benefits from treatment because of the current monitoring system. Therefore drug resistance testing will be useful before switching regimens in order to decide drugs in the new regimen. This will reduce the accumulation of multi-nucleoside and thymidine analog mutations in patients and preserve future drug options. The study has provided vital drug resistance data to guide policy on ART monitoring in Ghana, improved protocols for HIV genotyping at the Virology Department of the NMIMR and built capacity for drug resistance analyses of patients that fail ART in Ghana.
Genetic characterization of TEM-type ESBL-associated antibacterial resistance in Enterobacteriaceae in a tertiary hospital in Ghana
(2016-05-04) Oduro-Mensah, D.; Obeng-Nkrumah, N.; Bonney, E.Y.; Oduro-Mensah, E.; Twum-Danso, K.; Osei, Y.D.; Sackey, S.T.
Abstract Background Antibiotic resistance due to the presence of extended-spectrum beta-lactamases (ESBLs) among Enterobacteriaceae is a worldwide problem. Data from Ghana regarding this resistance mechanism is limited. This study was designed to investigate the presence of TEM-type ESBL genes, their locations and their conjugabilities in clinical isolates of enterobacteria collected from the Korle-Bu Teaching Hospital in Ghana. Methods Study isolates were characterized with respect to ESBL phenotype, TEM-type ESBL gene detection, location of the ESBL gene(s) and conjugability of the ESBL phenotype using nalidixic acid-resistant Escherichia coli K-12 as recipient. Phenotyping was by Kirby Bauer disk diffusion using cefpodoxime, ceftazidime, cefotaxime and their combinations with clavulanate. Gene detections were by PCR using blaTEM primers. Results Overall, 37.96 % of 137 clinical isolates showed ESBL phenotype. The ESBLs occurred mostly in Klebsiella spp. (42.3 %) and then Escherichia coli (34.6 %). The TEM gene was detected in 48.1 % of ESBL-positive isolates and was determined to be plasmid-borne in 24 of 25 blaTEM detections. Overall, 62.7 % of TEM-producing isolates transferred the ESBL phenotype by conjugation. Conclusions The results highlight the presence of TEM-type ESBLs in the Korle-Bu Teaching Hospital and show considerable risk of environmental contamination through the urine of infected persons. An inhibition zone chart was generated which indicates the possible presence of complex beta-lactamase types. The data points to the fact that the ESBL-producing bacteria may disseminate this resistance mechanism via conjugation.
Laboratory diagnosis of dual HIV-1/HIV-2 infection in Ghanaian patients
(East African Medical Journal 85(11): 534-543, 2008) Bonney, E.Y.; Sackey, S.T.; Brandful, J.A.
To determine the true prevalence of HIV dual infections in a previously characterised HIV seropositive patient group due to inconsistencies between different diagnostic methods. A cross-sectional study of an HIV seropositive group with different diagnostic methods. Setting: Three hospitals in the Northern, Ashanti and Greater Accra Regions of Ghana. One hundred and forty five HIV infected patients/individuals sampled from June to September 2002. Main Outcome Measures: Using serological and molecular methods, the seropositive status of HIV-infected patients, previously determined by a preliminary screening process, was confirmed and discrepancies noted. The data was used to propose a more accurate laboratory diagnosis of HIV dual infections involving HIV-1 and HIV-2. Result: HIV-1 infections were mostly accurately detected, but difficulties were encountered in diagnosing HIV-2 infections. To achieve a positive detection on confirmatory immunoblots, antibody concentration in some samples tested was enhanced by using larger volumes. In other cases, diagnosis of HIV infections by PCR, especially HIV-2, was possible only after increasing the DNA template or MgCl2 concentrations. Such samples would otherwise have been inaccurately scored for HIV infections. Conclusion: Based on the results of this study, we propose that the accurate diagnosis of HIV dual infections, especially HIV-2 component, must use an algorithm that involves PCR. Our results however underscore conclusions of a previous study that most dually seroreactive samples are predominantly HIV-1 infections with crossreactivity to HIV-2 antigens.