Limited Number Of Effective Drugs Research Articles

Surveillance of In Vitro Activity of Cefiderocol Against Carbapenem-Resistant Gram-Negative Clinical Isolates in a Tertiary Care Hospital.

Antibiotic resistance among Gram-negative bacterial isolates is increasingly observed. With the emergence of carbapenem-resistant and pan-resistant pathogens, treating these resistant infections is becoming more challenging due to the limited number of effective drugs. There is a desperate need for the discovery of new antibiotics with novel mechanisms of action. Cefiderocol is one such novel antibiotic with a unique siderophore-based mechanism of action, which has been recently approved for clinical use against drug-resistant pathogens. The present study aims to identify the in vitro activity of cefiderocol against major carbapenem-resistant clinical isolates, including those resistant to colistin. One hundred and one carbapenem-resistant clinical isolates were included in the study. Identification and antibiotic susceptibility testing were performed using the automated VITEK® 2 Compact (bioMérieux SA, Marcy-l'Étoile, France) identification and susceptibility testing system, except for colistin and cefiderocol. Colistin resistance in Enterobacterales and Pseudomonas aeruginosa was assessed using the agar dilution minimum inhibitory concentration method, while for Acinetobacter baumannii, broth microdilution method was employed. Cefiderocol susceptibility testing was conducted using the Kirby-Bauer disc diffusion method with 30 µg discs on standard Mueller-Hinton agar plates. For selected isolates, cefiderocol minimum inhibitory concentration detection was performed using broth microdilution with iron-depleted cation-adjusted Mueller-Hinton broth. Of the total 101 isolates, the majority (75, 74.25%) were Enterobacterales which includedKlebsiella pneumonia (42, 41.58%) and Escherichia coli (33, 32.67%), followed by Pseudomonas aeruginosa (13, 12.87%) and Acinetobacter baumannii (10, 9.9%). Only three (2.97%)of the isolates were Stenotrophomonas maltophilia. Most of the isolates were susceptible to cefiderocol, with only four (3.96%) isolates showing resistance. Colistin resistance was observed in six (6.12%) of the isolates. There was a good correlation between disc diffusion testing and broth microdilution testing for the detection of cefiderocol-resistant isolates. No cross-resistance with colistin was observed, as all colistin-resistant isolates were uniformly susceptible to cefiderocol Conclusion: Cefiderocol is highly effective with good in vitro activity against the majority of carbapenem-resistant pathogens. While some isolates do show resistance, it is relatively uncommon. Given its safety profile compared to colistin, cefiderocol can serve as an alternative to colistin to treat carbapenem-resistant infections and it may be considered even for the management of colistin-resistant cases. Disc diffusion testing is a reliable method for identifying cefiderocol-resistant isolates in routine clinical and diagnostic laboratories, especially in resource-limited settings.

Antiplasmodial activity and cytotoxicity of plant extracts from the Asteraceae and Rubiaceae families

The increasing resistance of parasites to antimalarial drugs and the limited number of effective drugs are the greatest challenges in the treatment of malaria. It is necessary to search for an alternative medicine for use as a new, more effective antimalarial drug. Therefore, this study aimed to evaluate the in vitro antimalarial activity and cytotoxicity of extracts from plants belonging to the Asteraceae and Rubiaceae families. The phytoconstituents of one hundred ten ethanolic and aqueous extracts from different parts of twenty-three plant species were analyzed. Evaluation of their antimalarial activities against the chloroquine (CQ)-resistant Plasmodium falciparum (K1) strain was carried out using the lactate dehydrogenase (pLDH) assay, and their cytotoxicity in Vero cells was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric method. A total of 40.91% of the extracts were active antimalarial agents. Three extracts (2.73%) exhibited high antiplasmodial activity (IC50 < 10 μg/ml), twenty-four extracts (21.82%) were moderately active with IC50 values ranging from 10–50 μg/ml, and eighteen extracts (16.36%) were mildly active with IC50 values ranging from 50–100 μg/ml. The ethanolic leaf extract of Mussaenda erythrophylla (Dona Trining; Rubiaceae) exhibited the highest activity against P. falciparum, with an IC50 value of 3.73 μg/ml and a selectivity index (SI) of 30.74, followed by the ethanolic leaf extract of Mussaenda philippica Dona Luz x M. flava (Dona Marmalade; Rubiaceae) and the ethanolic leaf extract of Blumea balsamifera (Camphor Tree; Asteraceae), with IC50 values of 5.94 and 9.66 μg/ml and SI values of 25.36 and >20.70, respectively. GC–MS analysis of these three plant species revealed the presence of various compounds, such as squalene, oleic acid amide, β-sitosterol, quinic acid, phytol, oleamide, α-amyrin, sakuranin, quercetin and pillion. In conclusion, the ethanolic leaf extract of M. erythrophylla, the leaf extract of M. philippica Dona Luz x M. flava and the leaf extract of B. balsamifera had strong antimalarial properties with minimal toxicity, indicating that compounds from these plant species have the potential to be developed into new antiplasmodial agents.

Uji Aktivitas Antiplasmodium Dari Isolat Kulit Batang Kayu Tammate (Lannea coromandelica Houtt. Merr.) Secara In-Vitro

One of the main causes of death an d a major public health problem is malaria. Some drug resistance and the limited number of effective drugs have given the community a sense of worry. This makes the discovery of new antimalarial compounds very necessary. Based on the results of exploration of natural materials, Javanese wood is one of the plants that is efficacious as an antimicrobial and is thought to be efficacious as antiplasmodium. This study was then conducted to find hexan and ethyl acetate isolates from the Java wood fraction (Lannea coromandelica Houtt. Merr.) Which effectively inhibited the development of Plasmodium falciparum in vitro. This research is a follow-up study from previous studies in testing the fraction of Javanese bark against antioxidant activity. The procedure starts from hexan and ethyl acetate isolates with five concentrations of 10 (µg / ml), 1 (µg / ml), 0.1 (µg / ml), 0.01 (µg / ml) and 0.001 (µg / ml) 3D7 strain of Plasmodium falciparum was measured based on the average percent resistance. The results of this study indicate that etil asetat isolate have IC 50 2,727 µg/ml, its mean moderate activity as antiplasmodium. While hexan isolate have IC 50 >10 µg/ml its mean not have or low antiplasmodium activity.

Recent progress in selective estrogen receptor downregulators (SERDs) for the treatment of breast cancer.

Selective estrogen receptor downregulators (SERDs) are a novel class of compounds capable of reducing the ERα protein level and blocking ER activity. Therefore, SERDs are considered as a significant therapeutic approach to treat ER+ breast cancer in both early stage and more advanced drug-resistant cases. After the FDA approval of a steroidal drug, fulvestrant, as a SERD for the treatment of breast cancer in patients who have progressed on antihormonal agents, several molecules with diverse chemical structures have been rapidly developed, studied and evaluated for selective estrogen receptor downregulation activity. Here we compile the promising SERDs reported in recent years and discuss the chemical structure and pharmacological profile of the most potent compound of the considered series. Because of the availability of only a limited number of effective drugs for the treatment of breast cancer, the quest for a potent SERD with respectable activity and bioavailability is still ongoing. The goal of this article is to make available to the reader an overview of the current progress in SERDs and provide clues for the future discovery and development of novel pharmacological potent SERDs for the treatment of breast cancer.

Redefining MDR-TB: Comparison of Mycobacterium tuberculosis clinical isolates from Russia and Taiwan

Multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis are global challenges due to the limited number of effective drugs for treatment. Treatment with less than 4–5 effective drugs might lead to the further emergence of drug resistance and poor clinical outcomes. For better prediction of treatment outcomes, we compared drug-resistance profiles of consecutive clinical MDR Mycobacterium tuberculosis isolates from high- and low-burden settings.This was a retrospective cohort study. We analysed 225 and 229 MDR isolates from Moscow (Russia) and Taiwan, respectively, obtained between 2014 and 2015. Drug susceptibility testing was performed by the Bactec MGIT 960 automated system and the agar proportion method. Detection of resistance-associated mutations in the M. tuberculosis genome was carried out by an array and/or sequencing of selected loci.The principal differences between resistance profiles of MDR isolates in the two countries were the percentages of pre-XDR (40.9% vs. 14.8%) and XDR (34.7% vs. 1.7%) isolates, both of which were significantly higher in Moscow isolates. Forty-eight (33%) of 147 MDR and pre-XDR Russian isolates fall into a group with less than four effective drugs, which accounts for 40% (N = 120) of these isolates. The other 60% in this group were XDR strains (N = 72). Consequently, the average number of effective anti-tuberculosis drugs for MDR-TB treatment was lower for Russian isolates (3 vs. 7). Furthermore, a notable percentage (9%) of isolates resistant to kanamycin harboured mutations in the whiB7 locus, which was not detected by molecular tests targeting common mutations in the rrs and eis loci. We found that 98.2% and 45.9% of MDR isolates from Moscow and Taiwan, respectively, were resistant to streptomycin.Molecular tests for detecting resistance to drugs other than rifampicin, isoniazid, fluoroquinolones, and second-line injectable drugs are needed for individualized therapy. The conventional MDR treatment schemes most probably fail in these cases due to the limited number of effective drugs.

A novel function of N-linked glycoproteins, alpha-2-HS-glycoprotein and hemopexin: Implications for small molecule compound-mediated neuroprotection.

Therapeutic agents to the central nervous system (CNS) need to be efficiently delivered to the target site of action at appropriate therapeutic levels. However, a limited number of effective drugs for the treatment of neurological diseases has been developed thus far. Further, the pharmacological mechanisms by which such therapeutic agents can protect neurons from cell death have not been fully understood. We have previously reported the novel small-molecule compound, 2-[mesityl(methyl)amino]-N-[4-(pyridin-2-yl)-1H-imidazol-2-yl] acetamide trihydrochloride (WN1316), as a unique neuroprotectant against oxidative injury and a highly promising remedy for the treatment of amyotrophic lateral sclerosis (ALS). One of the remarkable characteristics of WN1316 is that its efficacious doses in ALS mouse models are much less than those against oxidative injury in cultured human neuronal cells. It is also noted that the WN1316 cytoprotective activity observed in cultured cells is totally dependent upon the addition of fetal bovine serum in culture medium. These findings led us to postulate some serum factors being tightly linked to the WN1316 efficacy. In this study, we sieved through fetal bovine serum proteins and identified two N-linked glycoproteins, alpha-2-HS-glycoprotein (AHSG) and hemopexin (HPX), requisites to exert the WN1316 cytoprotective activity against oxidative injury in neuronal cells in vitro. Notably, the removal of glycan chains from these molecules did not affect the WN1316 cytoprotective activity. Thus, two glycoproteins, AHSG and HPX, represent a pivotal glycoprotein of the cytoprotective activity for WN1316, showing a concrete evidence for the novel glycan-independent function of serum glycoproteins in neuroprotective drug efficacy.

Antimalarial activity of Artemisia nilagirica against Plasmodium falciparum.

Malaria is one of the most prevalent vector borne infectious disease and a serious global health problem in the world. Treatment for malaria is commonly inadequate due to the lack of quality assured limited number of effective drugs, underline how important it is to discover new antimalarial plants from number of natural sources. In the present study, the efficacy of antimalarial activity was studied by taking six various (n-hexane, chloroform, petroleum ether, ethanol, methanol and aqueous) organic leaf extracts of Artemisia nilagirica (Clarke) Pamp. against malarial parasite Plasmodium falciparum. Promising antiplasmodial activity was found in all tested extracts; however, maximum 50% inhibitory concentration (IC50) values were noticed after 32h of incubation, which is 5.76±0.82, 7.09±1.09, 9.88±1.13, 10.24±1.52, 11.37±1.77 and 50.15±6.16µg/ml in methanol, chloroform, n-hexane, petroleum ether, ethanol and aqueous extracts, respectively. In conclusion, A. nilagirica leaf extract possesses antiplasmodial activity which may be used as a potent plant-based antimalarial drug in the future by investigating the hidden phytochemical/(s).

Identification of lead chemotherapeutic agents from medicinal plants against blood flukes and whipworms.

Schistosomiasis and trichuriasis are two of the most common neglected tropical diseases (NTD) that affect almost a billion people worldwide. There is only a limited number of effective drugs to combat these NTD. Medicinal plants are a viable source of parasiticides. In this study, we have investigated six of the 19 phytochemicals isolated from two Bhutanese medicinal plants, Corydalis crispa and Pleurospermum amabile, for their anthelmintic properties. We used the xWORM technique and Scanning Electron Microscope-based imaging to determine the activity of the compounds. Of the six compounds tested, isomyristicin and bergapten showed significant anthelmintic activity against Schistosoma mansoni and Trichuris muris with bergapten being the most efficacious compound one against both parasites (S. mansoni IC50 = 8.6 μg/mL and T. muris IC50 = 10.6 μg/mL) and also against the schistosomulum stage of S. mansoni. These two compounds induced tegumental damage to S. mansoni and affected the cuticle, bacillary bands and bacillary glands of T. muris. The efficacy against multiple phylogenetically distinct parasites and different life stages, especially the schistosomulum where praziquantel is ineffective, makes isomyristicin and bergapten novel scaffolds for broad-spectrum anthelmintic drug development that could be used for the control of helminths infecting humans and animals.

Recent Development in Identification of Potential Novel Therapeutic Targets Against Trypanosomatids.

Trypanosomatids continue to cause suffering among human and wide range of animal population and have enormous health, social and economic impact. The present constraints in control of trypanosomosis are availability of limited number of effective drugs with narrow safety index, nonavailability of vaccines due to immune evasion mechanisms developed by the parasite and drug resistance problem. The kinetoplastids/ trypanosomatids possess unique kinetoplast DNA structure and express hundreds of membrane transport proteins that allow them to take up nutrients, establish ion gradients, efflux metabolites, translocate compounds from one intracellular compartment to another, and take up or export drugs. In this context, there is urgent need of application of innovative strategies for identification of novel therapeutic drug targets affecting metabolic pathways essential for survival of the parasites using modern molecular approaches (functional/genomics/ proteomics/bioinformatics). In this review we have discussed existing drugs in use for treatment and outline of emerging approaches in identification and evaluation of potential novel therapeutic targets against trypanosomatids.

A simple and inexpensive haemozoin-based colorimetric method to evaluate anti-malarial drug activity

BackgroundThe spread of drug resistance in malaria parasites and the limited number of effective drugs for treatment indicates the need for new anti-malarial compounds. Current assays evaluating drugs against Plasmodium falciparum require expensive materials and equipment, thus limiting the search for new drugs, particularly in developing countries. This study describes an inexpensive procedure that is based on the advantage of a positive correlation between the haemozoin level of infected erythrocytes and parasite load.MethodsThe relationship between parasitaemia and the haemozoin level of infected erythrocytes was investigated after converting haemozoin into monomeric haem. The 50% inhibitory concentration (IC50) values of chloroquine, quinine, artemisinin, quinidine and clotrimazole against P. falciparum K1 and 9A strains were determined using the novel assay method.ResultsThe haemozoin of parasites was extracted and converted into monomeric haem, allowing the use of a colorimeter to efficiently and rapidly measure the growth of the parasites. There was a strong and direct linear relationship between the absorbance of haem converted from haemozoin and the percentage of the parasite (R2 = 0.9929). Furthermore, the IC50 values of drugs were within the range of the values previously reported.ConclusionThe haemozoin-based colorimetric assay can be considered as an alternative, simple, robust, inexpensive and convenient method, making it applicable in developing countries.

In vitro antimalarial activity of medicinal plant extracts against Plasmodium falciparum

Malaria is a major global public health problem, and the alarming spread of drug resistance and limited number of effective drugs now available underline how important it is to discover new antimalarial compounds. In the present study, ten plants were extracted with ethyl acetate and methanol and tested for their antimalarial activity against chloroquine (CQ)-sensitive (3D7) and CQ-resistant (Dd2 and INDO) strains of Plasmodium falciparum in culture using the fluorescence-based SYBR Green assay. Plant extracts showed moderate to good antiparasitic effects. Promising antiplasmodial activity was found in the extracts from two plants, Phyllanthus emblica leaf 50% inhibitory concentration (IC₅₀) 3D7: 7.25 μg/mL (ethyl acetate extract), 3.125 μg/mL (methanol extract), and Syzygium aromaticum flower bud, IC₅₀ 3D7:13 μg/mL, (ethyl acetate extract) and 6.25 μg/mL (methanol extract). Moderate activity (30-75 μg/mL) was found in the ethyl acetate and methanol extracts of Abrus precatorius (seed) and Gloriosa superba (leaf); leaf ethyl acetate extracts of Annona squamosa and flower of Musa paradisiaca. The above mentioned plant extracts were also found to be active against CQ-resistant strains (Dd2 and INDO). Cytotoxicity study with P. emblica leaf and S. aromaticum flower bud, extracts showed good therapeutic indices. These results demonstrate that leaf ethyl acetate and methanol extracts of P. emblica and flower bud extract of S. aromaticum may serve as antimalarial agents even in their crude form. The isolation of compounds from P. emblica and S. aromaticum seems to be of special interest for further antimalarial studies.

In vitro antimalarial activity of traditionally used Western Ghats plants from India and their interactions with chloroquine against chloroquine-resistant Plasmodium falciparum

Malaria is a major global public health problem, and the alarming spread of drug resistance and limited number of effective drugs now available underline how important it is to discover new antimalarial compounds. An ethnopharmacological investigation was undertaken on Western Ghats plants traditionally used to treat malaria in India; 50 plants were very carefully selected from a total of 372 plants, and 200 extracts were prepared and tested for in vitro antiplasmodial activity alone and in combination with chloroquine (CQ) against CQ-resistant Plasmodium falciparum (strain MRC-Pf-43). In in vitro antiplasmodial activity, when plant extract alone is used, 29 extracts (or 14.5%) showed significant high in vitro antiplasmodial activity with IC(50) values ranging from 3.96 to 4.85 μg/ml, 53 extracts (or 26.5%) showed significant good in vitro antiplasmodial activity with IC(50) values ranging from 5.02 to 9.87 μg/ml, and 28 extracts (or 14%) showed significant moderate in vitro antiplasmodial activity with IC(50) values ranging from 10.87 to 14 μg/ml, respectively. In combination with CQ, 103 extracts (or 51.5%) showed significant synergistic in vitro antiplasmodial activities with synergistic factor values ranging from 1.03 to 1.92, and these activities were up to a fold higher with CQ, suggesting synergistic interactions of the two drugs. Our investigation has confirmed that above 62.1% of the plant extracts showed moderate to high in vitro antiplasmodial activity when used alone, and in combination with CQ, 55.7% of the extracts showed borderline to good synergistic activity.

Antimalarial and cytotoxic activities of ethnopharmacologically selected medicinal plants from South Vietnam

Malaria is a major global public health problem and the alarming spread of drug resistance and limited number of effective drugs now available underline how important it is to discover new antimalarial compounds. An ethnopharmacological investigation was undertaken of medicinal plants traditionally used to treat malaria in the South Vietnam. Forty-nine plants were identified, 228 extracts were prepared and tested for their in vitro activity against Plasmodium falciparum, and assessed for any cytotoxicity against the human cancer cell line HeLa and the embryonic lung MRC5 cell line. In a first screening at a concentration of 10 μg/ml, 92 extracts from 46 plants showed antiplasmodial activity (parasite growth inhibition >30%). The IC 50 values of the most active extracts were determined as well as their selectivity towards Plasmodium falciparum in comparison to their cytotoxic effects against the human cell lines. Six plants showed interesting antiplasmodial activity (IC 50 ranging from 0.4 to 8.6 μg/ml) with a good selectivity: two Menispermaceae, Arcangelisia flava (L.) Merr. and Fibraurea tinctoria Lour., and also Harrisonia perforata (Blanco) Merr. (Simaroubaceae), Irvingia malayana Oliv. ex Benn. (Irvingiaceae), Elaeocarpus kontumensis Gagn. (Elaeocarpaceae) and Anneslea fragrans Wall. (Theaceae).