Antibiotic prescribing practices in community and clinical settings during the COVID-19 pandemic in Nairobi, Kenya.

The COVID-19 pandemic has significantly impacted healthcare systems, including antibiotic use practices. We present data on patterns of antibiotic dispensing and use in community and hospital settings respectively in Nairobi, Kenya during the pandemic. We conducted interviews with 243 pharmacies in Nairobi using a standardised questionnaire from November to December 2021. The data collected included demographic characteristics, antibiotic customers, types of antibiotics sold, and antibiotic prescribing practices. Additionally, we retrospectively reviewed health records for 992 and 738 patients admitted in COVID-19 and general wards at two large inpatient hospitals between April 2020 and May 2021, and January 2019 to October 2021, respectively. Demographic, utilisation of laboratory services, treatment, clinical, and outcome data were collected using a modified Global WHO Point Prevalence Surveys (Global-PPS) tool. Almost all pharmacies (91.4%) served customers suspected of having COVID-19 with a mean weekly number of 15.6 customers. All pharmacies dispensed antibiotics, mainly azithromycin and beta lactams to suspected COVID-19 infected customers. 83.4% of hospitalised COVID-19 patients received at least one antibiotic at some point during their hospitalisation, which was significantly higher than the 53.8% in general ward patients (p<0.001). Similarly, the average number of antibiotics administered to COVID-19 patients was higher than that of patients in the general ward (1.74 vs 0.9). Azithromycin and ceftriaxone were the most commonly used antibiotics in COVID-19 patients compared to ceftriaxone and metronidazole in the general wards. Only 2% of antibiotic prescriptions for COVID-19 patients were supported by microbiological investigations, which was consistent with the proportion of 6.8% among the general ward population. Antibiotics were commonly prescribed to customers and patients suspected of having COVID-19 either in community pharmacies or in hospital, without a prescription or laboratory diagnosis. These findings emphasize the crucial role of antibiotic stewardship, particularly in community pharmacies, in the context of COVID-19.

MAIP: An Open-Source Tool to Enrich High-Throughput Screening Output and Identify Novel, Druglike Molecules with Antimalarial Activity.

Efforts to tackle malaria must continue for a disease that threatens half of the global population. Parasite resistance to current therapies requires new chemotypes that are able to demonstrate effectiveness and safety. Previously, we developed a machine-learning-based approach to predict compound antimalarial activity, which was trained on the compound collections of several organizations. The resulting prediction platform, MAIP, was made freely available to the scientific community and offers a solution to prioritize molecules of interest in virtual screening and hit-to-lead optimization. Here, we experimentally validate MAIP and demonstrate how the approach was used in combination with a robust compound selection workflow and a recently introduced innovative high-throughput screening (HTS) cascade to select and purchase compounds from a public library for subsequent experimental screening. We observed a 12-fold enrichment compared with a randomly selected set of molecules, and the eight hits we ultimately selected exhibit good potency and absorption, distribution, metabolism, and excretion (ADME) profiles.

Exploring a Tetrahydroquinoline Antimalarial Hit from the Medicines for Malaria Pathogen Box and Identification of its Mode of Resistance as PfeEF2.

New antimalarial treatments with novel mechanism of action are needed to tackle Plasmodium falciparum infections that are resistant to first-line therapeutics. Here we report the exploration of MMV692140 (2) from the Pathogen Box, a collection of 400 compounds that was made available by Medicines for Malaria Venture (MMV) in 2015. Compound 2 was profiled in in vitro models of malaria and was found to be active against multiple life-cycle stages of Plasmodium parasites. The mode of resistance, and putatively its mode of action, was identified as Plasmodium falciparum translation elongation factor 2 (PfeEF2), which is responsible for the GTP-dependent translocation of the ribosome along mRNA. The compound maintains activity against a series of drug-resistant parasite strains. The structural motif of the tetrahydroquinoline (2) was explored in a chemistry program with its structure-activity relationships examined, resulting in the identification of an analog with 30-fold improvement of antimalarial asexual blood stage potency.

Replenishing the malaria drug discovery pipeline: Screening and hit evaluation of the MMV Hit Generation Library 1 (HGL1) against asexual blood stage Plasmodium falciparum, using a nano luciferase reporter read-out.

A central challenge of antimalarial therapy is the emergence of resistance to the components of artemisinin-based combination therapies (ACTs) and the urgent need for new drugs acting through novel mechanism of action. Over the last decade, compounds identified in phenotypic high throughput screens (HTS) have provided the starting point for six candidate drugs currently in the Medicines for Malaria Venture (MMV) clinical development portfolio. However, the published screening data which provided much of the new chemical matter for malaria drug discovery projects have been extensively mined. Here we present a new screening and selection cascade for generation of hit compounds active against the blood stage of Plasmodium falciparum. In addition, we validate our approach by testing a library of 141,786 compounds not reported earlier as being tested against malaria. The Hit Generation Library 1 (HGL1) was designed to maximise the chemical diversity and novelty of compounds with physicochemical properties associated with potential for further development. A robust HTS cascade containing orthogonal efficacy and cytotoxicity assays, including a newly developed and validated nanoluciferase-based assay was used to profile the compounds. 75 compounds (Screening Active hit rate of 0.05%) were identified meeting our stringent selection criteria of potency in drug sensitive (NF54) and drug resistant (Dd2) parasite strains (IC50 ≤ 2 µM), rapid speed of action and cell viability in HepG2 cells (IC50 ≥ 10 µM). Following further profiling, 33 compounds were identified that meet the MMV Confirmed Active profile and are high quality starting points for new antimalarial drug discovery projects.

Examination of WHO/INRUD Core Drug Use Indicators at Public Primary Healthcare Centers in Kisii County, Kenya.

BACKGROUND: Irrational drug use is a global problem. However, the extent of the problem is higher in low-income countries. This study sets out to assess and characterize drug use at the public primary healthcare centers (PPHCCs) in a rural county in Kenya, using the World Health Organization/International Network for the Rational Use of Drugs (WHO/INRUD) core drug use indicators methodology. METHODS: Ten PPHCCs were randomly selected. From each PPHCC, ninety prescriptions from October to December 2018 were sampled and data extracted. Three hundred (30 per PPHCC) patients and ten (1 per PPHCC) dispensers were also observed and interviewed. The WHO/INRUD core drug use indicators were used to assess the patterns of drug use. RESULTS: The average number of drugs per prescription was 2.9 (SD 0.5) (recommended: 1.6-1.8), and the percentage of drugs prescribed by generic names was 27.7% (recommended: 100%); the percentage of prescriptions with an antibiotic was 84.8% (recommended: 20.0-26.8%), and with an injection prescribed was 24.9% (recommended: 13.4-24.1%). The percentage of prescribed drugs from the Kenya Essential Medicines List was 96.7% (recommended: 100%). The average consultation time was 4.1 min (SD 1.7) (recommended: ≥10 min), the average dispensing time was 131.5 sec (SD 41.5) (recommended: ≥90 sec), the percentage of drugs actually dispensed was 76.3% (recommended: 100%), the percentage of drugs adequately labeled was 22.6% (recommended: 100%), and the percentage of patients with correct knowledge of dispensed drugs was 54.7% (recommended: 100%). Only 20% of the PPHCCs had a copy of KEML available, and 80% of the selected essential drugs assessed were available. CONCLUSION: The survey shows irrational drug use practices, particularly polypharmacy, nongeneric prescribing, overuse of antibiotics, short consultation time, and inadequacy of drug labeling. Effective programs and activities promoting the rational use of drugs are the key interventions suggested at all the health facilities.

Metformin's effectiveness in preventing prednisone-induced hyperglycemia in hematological cancers.

BACKGROUND: Research has established the development of steroid-induced hyperglycemia as a glucometabolic side effect of high-dose prednisone therapy. Few studies, however, have demonstrated preventative measures that could effectively curtail this side effect in susceptible patients undergoing high-dose prednisone treatment. OBJECTIVE: To assess metformin's prophylactic effectiveness of prednisone-induced hyperglycemia among hematological cancer patients. SETTING: Prospective randomized controlled trial conducted at the Kenyatta National Hospital Oncology Clinic and Wards, Nairobi, Kenya. METHOD: Non-hyperglycemic hematological cancer patients on current or newly initiated high-dose prednisone-based chemotherapy were randomized to receive metformin 850 mg once then 850 mg twice daily for two successive weeks each or to the control group receiving the standard care. Patients were subjected to once weekly fasting and 2-h postprandial glucose measurements for four weeks. MAIN OUTCOME MEASURE: The primary outcome of measure was the development of hyperglycemia defined by fasting capillary blood glucose values >5.6 mmol/L or 2-h postprandial capillary blood glucose values >7.8 mmol/L. RESULTS: Eighteen of 24 randomized patients completed the study (11 control and 7 treatment). The proportion of the control subjects that developed prediabetes was 72.7% (95% confidence interval 45.5-90.9%) using fasting glucose and 54.5% (95% confidence interval 27.3-81.8%) using 2-h postprandial glucose. One treatment group participant developed prediabetes using fasting glucose, representing 14.3% (95% confidence interval 0-42.9%). No prediabetes was detected using the 2-h postprandial glucose. Analysis of mean fasting glucose between the two arms found no significant difference. However, significant differences in mean 2-h postprandial glucose were noted in week 2 (p = 0.0144), week 3 (p = 0.0095), and week 4 (p = 0.0074) of the study. Double dose (1700 mg) metformin was more effective in lowering blood glucose than single dose (850 mg) (p = 1.0000 (fasting), p = 0.4531(2-h postprandial). CONCLUSION: Metformin's prophylactic effectiveness was demonstrated in this randomized study on new and previously exposed non-diabetic cancer patients on high-dose prednisone-based chemotherapy.

Crystal Structures and Cytotoxicity of ent-Kaurane-Type Diterpenoids from Two Aspilia Species.

A phytochemical investigation of the roots of Aspilia plurisetaled to the isolation of ent-kaurane-type diterpenoids and additional phytochemicals (1⁻23). The structures of the isolated compounds were elucidated based on Nuclear Magnetic Resonance (NMR) spectroscopic and mass spectrometric analyses. The absolute configurations of seven of the ent-kaurane-type diterpenoids (3⁻6, 6b, 7 and 8) were determined by single crystal X-ray diffraction studies. Eleven of the compounds were also isolated from the roots and the aerial parts of Aspilia mossambicensis. The literature NMR assignments for compounds 1 and 5 were revised. In a cytotoxicity assay, 12α-methoxy-ent-kaur-9(11),16-dien-19-oic acid (1) (IC50 = 27.3 ± 1.9 µM) and 9ß-hydroxy-15α-angeloyloxy-ent-kaur-16-en-19-oic acid (3) (IC50 = 24.7 ± 2.8 µM) were the most cytotoxic against the hepatocellular carcinoma (Hep-G2) cell line, while 15α-angeloyloxy-16ß,17-epoxy-ent-kauran-19-oic acid (5) (IC50 = 30.7 ± 1.7 µM) was the most cytotoxic against adenocarcinomic human alveolar basal epithelial (A549) cells.

Prescription patterns and adequacy of blood pressure control among adult hypertensive patients in Kenya; findings and implications.

BACKGROUND: Hypertension is a major cause of global morbidity and mortality, with high prevalence rates in Africa including Kenya. Consequently, it is imperative to understand current treatment approaches and their effectiveness in practice. Currently, there is paucity of such data in Kenya, which is a concern. The aim is to describe prescribing patterns and adequacy of blood pressure (BP) control in adult hypertensive patients to guide future practice. METHOD: Retrospective study of patients attending a sub-county outpatient clinic combined with qualitative interviews. RESULTS: 247 hypertensive patients, predominantly female, mean age 55.8 years on antihypertensive therapy for 1-5 years, were analyzed. ACEIs and thiazide diuretics were the most commonly prescribed drugs, mainly as combination therapy. Treatment typically complied with guidelines, mainly for stage 2 hypertension (75%). BP control was observed in 46% of patients, with a significant reduction in mean systolic (155 to 144 mmHg) and diastolic (91 to 83 mmHg) BP (P < 0.001). Patients on ≥2 antihypertensive drugs were more likely to have uncontrolled BP (OR:1.9, p = 0.021). CONCLUSION: Encouragingly good adherence to guidelines was helped by training. Poor blood pressure control in the majority needs to be addressed. Additional training of prescribers and follow-up of measures to improve BP control will be introduced and followed up.

Computer-Aided Drug Discovery Approaches against the Tropical Infectious Diseases Malaria, Tuberculosis, Trypanosomiasis, and Leishmaniasis.

Despite the tremendous improvement in overall global health heralded by the adoption of the Millennium Declaration in the year 2000, tropical infections remain a major health problem in the developing world. Recent estimates indicate that the major tropical infectious diseases, namely, malaria, tuberculosis, trypanosomiasis, and leishmaniasis, account for more than 2.2 million deaths and a loss of approximately 85 million disability-adjusted life years annually. The crucial role of chemotherapy in curtailing the deleterious health and economic impacts of these infections has invigorated the search for new drugs against tropical infectious diseases. The research efforts have involved increased application of computational technologies in mainstream drug discovery programs at the hit identification, hit-to-lead, and lead optimization stages. This review highlights various computer-aided drug discovery approaches that have been utilized in efforts to identify novel antimalarial, antitubercular, antitrypanosomal, and antileishmanial agents. The focus is largely on developments over the past 5 years (2010-2014).

Synthesis, biological evaluation and mechanistic studies of totarol amino alcohol derivatives as potential antimalarial agents.

Herein we report on the semisynthesis and biological evaluation of ß-amino alcohol derivatives of the natural product totarol and other simple aromatic systems. All ß-amino alcohol derivatives of totarol exhibited higher antiplasmodial activity than totarol [IC(50): 11.69 µM (K1, chloroquine and multi-drug resistant strain), and 11.78 µM (D10, chloroquine sensitive strain)]-12e was the most active [IC(50): 0.63 µM (K1), and 0.61 µM (D10)]. The phenyl and naphthyl ß-amino alcohol derivatives were much less active than their corresponding totarol equivalents. The majority of the ß-amino alcohol derivatives of totarol were more active against K1 than the D10 strains of Plasmodium falciparum, a trend similar to the inverse relationship observed with the established aryl-amino alcohol antimalarial mefloquine. Selected compounds were shown to affect erythrocyte morphology, inhibit erythrocyte invasion and trigger CQ accumulation.

Effects of highly active novel artemisinin-chloroquinoline hybrid compounds on ß-hematin formation, parasite morphology and endocytosis in Plasmodium falciparum.

4-Aminoquinolines were hybridized with artemisinin and 1,4-naphthoquinone derivatives via the Ugi-four-component condensation reaction, and their biological activities investigated. The artemisinin-containing compounds 6a-c and its salt 6c-citrate were the most active target compounds in the antiplasmodial assays. However, despite the potent in vitro activities, they also displayed cytotoxicity against a mammalian cell-line, and had lower therapeutic indices than chloroquine. Morphological changes in parasites treated with these artemisinin-containing hybrid compounds were similar to those observed after addition of artemisinin. These hybrid compounds appeared to share mechanism(s) of action with both chloroquine and artemisinin: they exhibited potent ß-hematin inhibitory activities; they caused an increase in accumulation of hemoglobin within the parasites that was intermediate between the increase observed with artesunate and chloroquine; and they also appeared to inhibit endocytosis as suggested by the decrease in the number of transport vesicles in the parasites. No cross-resistance with chloroquine was observed for these hybrid compounds, despite the fact that they contained the chloroquinoline moiety. The hybridization strategy therefore appeared to be borrowing the best from both classes of antimalarials.

Enone- and chalcone-chloroquinoline hybrid analogues: in silico guided design, synthesis, antiplasmodial activity, in vitro metabolism, and mechanistic studies.

Analogues of the previously reported antimalarial hybrid compounds 8b and 12 were proposed with the aim of identifying compounds with improved solubility and retained antimalarial potency. In silico characterization predicted improved solubilities of the analogues, particularly at low pH; they retained acceptable predicted permeability properties but were predicted to be susceptible to hepatic metabolism. These analogues were synthesized and found to exhibit notable in vitro antimalarial activity. Compounds 25 and 27 were the most active of the analogues. In vitro metabolism studies indicated susceptibility of the analogues to hepatic metabolism. There was also evidence of primary glucuronidation for analogues 24-27. Presumed cis-trans isomerism of 12, 22, and 23 under in vitro metabolism assay conditions was also observed, with differences in the nature and rates of metabolism observed between isomers. Biochemical studies strongly suggested that inhibition of hemozoin formation is the primary mechanism of action of these analogues.

Antiplasmodial and antitumor activity of dihydroartemisinin analogs derived via the aza-Michael addition reaction.

A series of dihydroartemisinin derivatives were synthesized via an aza-Michael addition reaction to a dihydroartemisinin-based acrylate and were evaluated for antiplasmodial and antitumor activity. The target compounds showed excellent antiplasmodial activity, with dihydroartemisinin derivatives 5, 7, 9 and 13 exhibiting IC(50) values of ≤10 nM against both D10 and Dd2 strains of Plasmodium falciparum. Derivative 4d was the most active against the HeLa cancer cell line, with an IC(50) of 0.37 µM and the highest tumor specificity.

How can natural products serve as a viable source of lead compounds for the development of new/novel anti-malarials?

Malaria continues to be an enormous global health challenge, with millions of new infections and deaths reported annually. This is partly due to the development of resistance by the malaria parasite to the majority of established anti-malarial drugs, a situation that continues to hamper attempts at controlling the disease. This has spurred intensive drug discovery endeavours geared towards identifying novel, highly active anti-malarial drugs, and the identification of quality leads from natural sources would greatly augment these efforts. The current reality is that other than compounds that have their foundation in historic natural products, there are no other compounds in drug discovery as part of lead optimization projects and preclinical development or further that have originated from a natural product start-point in recent years. This paper briefly presents both classical as well as some more modern, but underutilized, approaches that have been applied outside the field of malaria, and which could be considered in enhancing the potential of natural products to provide or inspire the development of anti-malarial lead compounds.

Design, synthesis and in vitro antimalarial evaluation of triazole-linked chalcone and dienone hybrid compounds.

A targeted series of chalcone and dienone hybrid compounds containing aminoquinoline and nucleoside templates was synthesized and evaluated for in vitro antimalarial activity. The Cu(I)-catalyzed cycloaddition of azides and terminal alkynes was applied as the hybridization strategy. Several chalcone-chloroquinoline hybrid compounds were found to be notably active, with compound 8b the most active, exhibiting submicromolar IC(50) values against the D10, Dd2 and W2 strains of Plasmodium falciparum.

Chloroquine resistance: proposed mechanisms and countermeasures.

Malaria has been, and remains, one of the biggest global health concerns as far as infectious diseases are concerned, with yearly incidence and mortality figures running into millions. One of the major drawbacks to the control of this disease has been the emergence of drug resistant strains of the causative agent, which limits the successful use of many clinically available antimalarial drugs. This review discusses chloroquine resistance; it highlights some of the proposed molecular mechanisms of chloroquine resistance, but dwells more on efforts at reversing chloroquine resistance and the concept of chloroquine resistance-reversal agents.

Synthesis, antimalarial and antitubercular activity of acetylenic chalcones.

A series of acetylenic chalcones were evaluated for antimalarial and antitubercular activity. The antimalarial data for this series suggests that growth inhibition of the W2 strain of Plasmodium falciparum can be imparted by the introduction of a methoxy group ortho to the acetylenic group. Most compounds were more active against non-replicating than replicating cultures of Mycobacterium tuberculosis H(37)Rv, an unusual pattern with respect to existing anti-TB agents.