Stephen Y. Gbedema

Antibiotic producing microorganisms from River Wiwi, Lake Bosomtwe and the Gulf of Guinea at Doakor Sea Beach, Ghana

BackgroundMicroorganisms have provided a wealth of metabolites with interesting activities such as antimicrobial, antiviral and anticancer. In this study, a total of 119 aquatic microbial isolates from 30 samples (taken from water bodies in Ghana) were screened by the agar-well diffusion method for ability to produce antibacterial-metabolites.ResultsAntibacterial activity was exhibited by 27 of the isolates (14 bacteria, 9 actinomycetes and 4 fungi) against at least one of the indicator microorganisms: Enterococcus faecalis (ATCC 29212), Bacillus thuringiensis (ATCC 13838), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Proteus vulgaris (NCTC 4635) and Bacillus Subtilis (NCTC 10073). A sea isolate MAI2 (identified as a strain of Pseudomonas aeruginosa) exhibited the highest antibacterial activity (lowest zone of inhibition = 22 mm). The metabolites of MAI2 extracted with chloroform were stable to heat and gave minimum inhibitory concentrations ranging between 250 and 2000 μg/ml. Bioautography of the extract revealed seven active components.ConclusionThis study has therefore uncovered the potential of water bodies in the West African sub-region as reservoirs of potent bioactive metabolite producing microorganisms.

Antibiotic resistance patterns of escherichia coli isolates from hospitals in Kumasi, Ghana

Nosocomial infections are infections acquired by a patient as a result of treatment in a hospital or healthcare service providing center and symptoms occurs within a short period of hospitalization. The study was to determine the antibiotic resistance patterns of Escherichia coli isolated from Kumasi-South, Tafo and Suntreso Hospitals, Kumasi, Ghana. Total of 600 swabs samples from the hospitals were collected between January and June, 2010. The isolates were identified using morphological and biochemical means. A total of 97 E. coli isolates were obtained from the hospitals. Beds in hospital wards had the highest number of E. coli strains (53.6%), followed by floors (20.6%) while drainages had the least isolates (3.1%). Majority of the E. coli isolates (90.7%) exhibited resistance to ampicillin while 6.2 and 3.1% showed intermediate and sensitive respectively. Co-trimoxazole, 78.4% of the isolates were resistant while 9.3 and 12.4% exhibited intermediate and sensitive responses respectively. E. coli isolates (28.6 to 46.4%) were resistant to gentamicin, ciprofloxacin and ceftriaxone while 14.4 to 47.4% gave intermediate responses. Most isolates (80.4%) exhibited multi-drug resistance. There is a need to observe proper personal hygiene, use of effective disinfectants and proper disposal of contaminated/pathogenic materials in these hospitals to control nosocomial infections.

ACCURACY OF DIAGNOSIS OF INTESTINAL HELMINTH PARASITES IN A REFERENCE DIAGNOSTIC LABORATORY IN THE ASHANTI REGION OF GHANA

There are reports of many intestinal-helminth negative stool specimens in most laboratories in Ghana even though the prevalence of these infections seems to be on the increase. In this study 2000 stool specimens collected between May and October 2008 in The Reference Laboratory of the Ashanti Region of Ghana were screened using Direct Wet Mount, Kato-Katz and Formol-Ether Concentration methods. The Formol-Ether Concentration method gave the highest prevalence (11.1%) of helminth parasites made up of hookworm, Dicrocoelium dendriticum, Strongyloides stercoralis, Schistosoma mansoni, Hymenolepis nana, Taenia species and Trichuris trichiura. The direct wet mount and Kato-Katz detected total prevalence of 3.2% and 5.1% respectively. Kato-Katz showed good agreement with the formol-ether concentration in the detection of hookworms, T. trichiura and S. mansoni infections (99.1% sensitivity) with positive and negative predictive values of 100% and 99.5% respectively. This study confirmed earlier reports that the traditional Direct Wet Mount screening test is less sensitivity hence the employment of Formol-Ether Concentration as a confirmatory test in routine laboratory examination of stool samples will significantly reduce misdiagnosis of intestinal helminth infections and its attendant public health consequences.

Synthesis, biological profiling and mechanistic studies of 4-aminoquinoline-based heterodimeric compounds with dual trypanocidal-antiplasmodial activity.

Dual submicromolar trypanocidal-antiplasmodial compounds have been identified by screening and chemical synthesis of 4-aminoquinoline-based heterodimeric compounds of three different structural classes. In Trypanosoma brucei, inhibition of the enzyme trypanothione reductase seems to be involved in the potent trypanocidal activity of these heterodimers, although it is probably not the main biological target. Regarding antiplasmodial activity, the heterodimers seem to share the mode of action of the antimalarial drug chloroquine, which involves inhibition of the haem detoxification process. Interestingly, all of these heterodimers display good brain permeabilities, thereby being potentially useful for late stage human African trypanosomiasis. Future optimization of these compounds should focus mainly on decreasing cytotoxicity and acetylcholinesterase inhibitory activity.

In vitro anti-plasmodial activity of three herbal remedies for malaria in Ghana: Adenia cissampeloides (Planch.) Harms., Termina liaivorensis A. Chev, and Elaeis guineensis Jacq.

Background: Herbal remedies of Adenia cissampeloides, Terminalia ivorensis, and Elaeis guineensis among others have been used in Ghana for the treatment of various ailments including malaria. However, most of these remedies have not been scientifically investigated. Objective: This study, therefore, seeks to investigate the anti-plasmodial activity of these plants. Materials and Methods: The ethanolic extracts of A. cissampeloides stem, T. ivorensis stem bark, and E. guineensis leaves were tested for in vitro anti-plasmodial activity against chloroquine-resistant strains of Plasmodium falciparum. Thin blood films were used to assess the level of parasitemia and growth inhibition of the extracts. Results: The IC 50 of A. cissampeloides, T. ivorensis, and E. guineensis were 8.521, 6.949, and 1.195 μg/ml, respectively, compared to artesunate with IC50 of 0.031 μg/ml. Conclusion: The result of this study appears to confirm the folkloric anti-malarial use these plants.

Prevalence and antibiotic resistance of coagulase-negative Staphylococci isolated from poultry farms in three regions of Ghana

The use of antibiotics in animal production has been associated with the development and spread of antibiotic-resistant organisms including commensals. Coagulase-negative Staphylococcus (CoNS) species, which were until recently considered non-pathogenic, have been associated with opportunistic infections and high resistance to several antibiotics. This study sought to determine the prevalence, identity, and phenotypic resistance of coagulase-negative Staphylococcus spp. isolated from some selected poultry farms and farm workers in the Ashanti, Brong Ahafo, and Greater Accra regions of Ghana. Poultry litter samples and oral swabs of poultry farm workers were collected, from which bacterial species were isolated, identified, and analyzed. Various selective media were used for the presumptive identification of the different species. Confirmation of bacterial identity was done using matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. Antibiotic susceptibility testing of the isolates was performed using the Kirby-Bauer disk diffusion method. Zones of growth inhibition were interpreted based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Two hundred and fifty-six coagulase-negative Staphylococcus spp., comprising S. sciuri (42.97%), S. lentus (35.94%), S. gallinarum (6.64%), S. xylosus (4.30%), S. haemolyticus (3.91%), S. saprophyticus (1.95%), and S. cohnii (0.39%) were confirmed by MALDI-TOF. CoNS were isolated from samples from the Brong Ahafo (48.83%), Ashanti (33.59%), and Greater Accra (17.78%) regions. Isolates from poultry litter constituted 55.47%, and farm workers 44.53%. All the isolates were susceptible to amoxicillin/clavulanic acid and amikacin. The isolates exhibited high resistance toward tetracycline (57.03%), doxycycline (43.75%), and oxacillin (43.36%). Multi-drug resistance (MDR) was observed in 19.14% of the isolates. MDR was higher in isolates obtained from poultry farm workers (61.22%) than isolates from poultry litter (38.78%). The above findings call for stricter monitoring of antibiotic usage in both animal production and in humans.

Clerodane diterpenes from Polyalthia longifolia (Sonn) Thw. var. pendula: Potential antimalarial agents for drug resistant Plasmodium falciparum infection.

BACKGROUND Plasmodium falciparum drug resistance is a major public health challenge in sub-Sahara Africa. Many people are now resorting to the use of herbs in managing malaria due to the increasing treatment failures with the conventional drugs. In this study the ethanolic extract of Polyalthia longifolia (Sonn) Thw. var. pendula, a variety fondly used in folklore medicine in Ghana was investigated for potential antimalarial drug development. METHOD The ethanolic extract of P. longifolia (Sonn) Thw. var. pendula stem bark was screened against the multidrug resistant, K1 strain of P. falciparum by the parasite lactate dehydrogenase (pLDH) assay and a good antiplasmodial activity (IC50 22.04± 4.23µg/ml) was observed which led to further chromatographic analysis in search for actives. RESULTS Bioassay guided fractionation of the extract yielded; three clerodane diterpenes [16-hydroxycleroda-3,13-dien-16,15-olide (1), 16-oxocleroda-3,13E-dien-15-oic acid (2) and 3,16-dihydroxycleroda-4(18),13(14)Z-dien-15,16-olide (3)], a steroid [beta-stigmasterol (4)] and two alkaloids [darienine (5) and stepholidine (6)]. While compounds 4, 5 and 6 exhibited weak antiplasmodial activity (IC50 22-105µg/ml), the clerodane diterpenes exhibited significantly potent (p<0.005) blood schizonticidal activity (IC50: 3-6µg/ml). This is the first report of the antiplasmodial activity of compounds 2 and 3. In combination assay with chloroquine, compounds 1, 2, 3 and 5 antagonized the antiplasmodial activity of chloroquine while 4 and 6 demonstrated a synergistic action. CONCLUSION The potent antiplasmodial activity of the extract of P. longifolia (Sonn) Thw. var. pendula and compounds therein strongly suggests its usefulness as an antimalarial agent and supports its inclusion or exploitation in formulations of herbal remedies for malaria in Ghana.

River Wiwi: A source of Schistosoma haematobium infection in school children in Kumasi, an urban African setting

Article published in African Journal of Microbiology Research Vol. 7(20), pp. 2213-2220, 14 May, 2013. Also available at http://www.academicjournals.org/AJMR

Concurrent Use of Herbal and Orthodox Medicines among Residents of Tamale, Northern Ghana, Who Patronize Hospitals and Herbal Clinics

Despite the development of more researched and formulated orthodox medicines, herbal medicines continue to be well patronized for persons across the world with some patrons concurrently using both forms, oblivious of the unwanted effects that may occur. Using a multistage sampling procedure, a semistructured questionnaire was used to collect data in April 2016 from 240 informants from three selected hospitals and three herbal clinics in Tamale, a city in northern Ghana. Using Statistical Package for the Social Sciences, binary logistic regression was used to determine sociodemographic predictors of concurrent use of herbal and orthodox medicines. Orthodox medicines were the drug of choice for 54.2% and 49.2% of patrons of hospitals and herbal clinics, respectively. Also, 67.5% of herbal clinic patrons used orthodox medicines, while 25.0% of hospital attendees used herbal medications prior to their visit to the health facilities. Up to 17.9% of respondents concurrently used herbal and orthodox medicines for their prevailing ailment with age, less than 30 years being the only predictor of this habit (p = 0.015; 95% CI, 1.183–4.793; cOR = 2.4). All health professionals including those in herbal clinics should therefore be interested in the drug history of their clients.