Emergence Of Multidrug Resistance Research Articles

Targeting breast cancer resistance protein (BCRP/ABCG2) in cancer.

Breast cancer is one of the most common cancers among women. Nowadays postoperative adjuvant chemotherapy is the mainstay for clinical treatment of breast cancer. However, the emergence of multidrug resistance (MDR) in breast cancer has become a main reason for the failure of clinical chemotherapy. Multiple studies have demonstrated that the formation of MDR in breast cancer is combined with ATP-binding transporters, which are the proteins that can lead to the drug resistance by pumping out chemotherapeutic drugs to reduce their intracellular accumulation. This kind of protein mainly includes P-glycoprotein (Pgp, ABCB1, MDR1), multidrug resistance-associated protein (MRP-1, ABCC1) and breast cancer resistance protein (BCRP, ABCG2). The former two transporters have been investigated deeply and widely, while the molecular mechanism of BCRP regulation of breast cancer drug resistance has relatively not much been explored in the area of breast cancer. How to design a novel, effective and non-toxic BCRP inhibitor to reverse the MDR of breast cancer, and boost the success rate of chemotherapy is a serious challenge at present. A detailed overview of the molecular role of BCRP-mediated breast cancer MDR and its inhibitors reported in recent years is provided in this article. The expectation is to provide ideas for clinically addressing MDR in breast cancer, and further guide the direction for the development of new anti-breast cancer drugs and reversal of breast cancer MDR drugs.

Design, synthesis and biological evaluation of biaryl amide derivatives as modulators of multi-drug resistance

The emergence of multi-drug resistance (MDR) presents a significant impediment to the efficacy of cancer treatment. Aberrant expression of ABC (ATP-binding cassette) transporters is acknowledged as one of the underlying factors contributing to MDR. P-glycoprotein (P-gp, MDR1, ABCB1), breast cancer resistance protein (BCRP, ABCG2), and MDR-associated protein 1 (MRP1, ABCC1) are members of the ABC transporter, and their over-expression usually occurs in drug-resistant tumor cells. In this work, the structure-activity relationships of the biaryl amide skeleton were systematically investigated via structural optimization step by step, which led to the identification of an exceptionally potent resistance reversal agent, D2. Compound D2 effectively reversed MDR to paclitaxel and cisplatin in A2780/T, A2780/CDDP and A549/T cell lines. It could directly bind to P-gp and downregulate the expression of both P-gp and MRP1. The treatment with D2 increased the intracellular accumulation of Rh123 and inhibited P-gp-mediated drug efflux of Rh123 in A2780/T cells. Therefore, compound D2 exhibits promising potential in overcoming multidrug resistance (MDR) induced by P-gp in cancer.

Differential Host Gene Expression in Response to Infection by Different Mycobacterium tuberculosis Strains-A Pilot Study.

Tuberculosis (TB) represents a global public health threat and is a leading cause of morbidity and mortality worldwide. Effective control of TB is complicated with the emergence of multidrug resistance. Yet, there is a fundamental gap in understanding the complex and dynamic interactions between different Mycobacterium tuberculosis strains and the host. In this pilot study, we investigated the host immune response to different M. tuberculosis strains, including drug-sensitive avirulent or virulent, and rifampin-resistant or isoniazid-resistant virulent strains in human THP-1 cells. We identified major differences in the gene expression profiles in response to infection with these strains. The expression of IDO1 and IL-1β in the infected cells was stronger in all virulent M. tuberculosis strains. The most striking result was the overexpression of many interferon-stimulated genes (ISGs) in cells infected with the isoniazid-resistant strain, compared to the rifampin-resistant and the drug-sensitive strains. Our data indicate that infection with the isoniazid-resistant M. tuberculosis strain preferentially resulted in cGAS-STING/STAT1 activation, which induced a characteristic host immune response. These findings reveal complex gene signatures and a dynamic variation in the immune response to infection by different M. tuberculosis strains.

Synthesis and evaluation of novel tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates as dual ABCB1/CYP1B1 inhibitors for overcoming MDR in cancer

The emergence of multidrug resistance (MDR) in malignant tumors is one of the major threats encountered currently by many chemotherapeutic agents. Among the various mechanisms involved in drug resistance, P-glycoprotein (P-gp, ABCB1), a member of the ABC transporter family that significantly increases the efflux of various anticancer drugs from tumor cells, and the metabolic enzyme CYP1B1 are widely considered to be two critical targets for overcoming MDR. Unfortunately, no MDR modulator has been approved by the FDA to date. In this study, based on pharmacophore hybridization, bioisosteric and fragment-growing strategies, we designed and synthesized 11 novel tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates as dual ABCB1/CYP1B1 inhibitors. Among them, the preferred compound A10 exhibited the best MDR reversal activity (IC50 = 0.25 μM, RF = 44.4) in SW620/AD300 cells, being comparable to one of the most potent third-generation P-gp inhibitors WK-X-34. In parallel, this dual ABCB1/CYP1B1 inhibitory effect drives compound A10 exhibiting prominent drug resistance reversal activity to doxorubicin (IC50 = 4.7 μM, RF = 13.7) in ABCB1/CYP1B1-overexpressing DOX-SW620/AD300-1B1 resistant cells, which is more potent than that of the CYP1B1 inhibitor ANF. Furthermore, although compound A2 possessed moderate ABCB1/CYP1B1 inhibitory activity, it showed considerable antiproliferative activity towards drug-resistant SW620/AD300 and MKN45-DDP-R cells, which may be partly related to the increase of PUMA expression to promote the apoptosis of the drug-resistant MKN45-DDP-R cells as confirmed by proteomics and western blot assay. These results indicated that the tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates may provide a fundamental scaffold reference for further discovery of MDR reversal agents.

Molecular characterization and genotype of multi-drug resistant Staphylococcus epidermidis in nasal carriage of young population, Mahasarakham, Thailand.

Staphylococcus epidermidis, a coagulase-negative staphylococcus, is a prevalent skin commensal that has increasingly been recognized as a significant pathogen, particularly in hospital environments, where it is associated with device-related infections. The emergence of multi-drug resistance and its ability to form biofilms complicate the clinical management of infections caused by this organism, posing a growing public health concern. This study aimed to investigate the nasal carriage of S. epidermidis among healthy young individuals and to analyze its antibiotic resistance patterns, resistance genes, and biofilm formation capabilities. Nasal swabs were collected from 40 undergraduate students at Mahasarakham University, Thailand, aged between 20 and 22 years. A total of 38 isolates were confirmed as S. epidermidis through both phenotypic and molecular characterization. Antibiotic susceptibility testing demonstrated resistance to various classes of antimicrobials, including beta-lactams, macrolides, and tetracyclines. Notably, five isolates exhibited methicillin resistance S. epidermidis (MRSE). Resistance genes, such as mecA, ermA, tetM, tetL, and tetK, were identified across the isolates, contributing to the observed resistance profiles. Biofilm formation assays revealed that most isolates displayed weak to moderate biofilm formation, with only one isolate demonstrating strong biofilm-forming capacity. Genetic analysis indicated a significant correlation between biofilm formation and the presence of the icaA gene, which is crucial for biofilm production. This study suggests the necessity for ongoing surveillance of nasal carriage of S. epidermidis to enhance understanding of its role in the dissemination of antimicrobial resistance and biofilm-associated infections, particularly within healthcare settings.

Liposomal Nanoformulation-encapsulated Paclitaxel for Reducing Chemotherapy Side Effects in Lung Cancer Treatments: Recent Advances and Future Outlooks.

Paclitaxel is one notable chemotherapy drug that is used to treat a number of cancers, including lung cancer. Nevertheless, it has drawbacks such as toxicity, low solubility in water, and the emergence of multidrug resistance (MDR). This article reviews the use of liposomal formulations to improve paclitaxel administration and efficacy for lung cancer therapy. Paclitaxel's pharmacological characteristics can be improved by liposomes through increased solubility, extended circulation, passive tumor targeting through leaky vasculature, and decreased side effects. Recent developments in paclitaxel liposomal formulations, including as cationic liposomes, conventional liposomes, targeted liposomes with particular ligands, and liposome-loaded microorganisms, are outlined in this article. In comparison to free paclitaxel, these nanoformulations exhibit enhanced cytotoxicity, cellular uptake, apoptosis, tumor growth suppression, and anticancer effects in lung cancer cell lines and animal models. One efficient way to get around the drawbacks of paclitaxel is to alter its size, makeup, and surface characteristics. This will let the medication accumulate and penetrate tumors more easily, avoid multidrug resistance, and cause less systemic toxicity. The article explores clinical studies showcasing the safety and therapeutic efficacy of liposomal paclitaxel for individuals afflicted with lung cancer. In its entirety, the document provides an in-depth examination of the potential enhancement in paclitaxel's dispersion and anti-tumor impacts through the utilization of liposomal technology when addressing diverse manifestations of lung cancer.

Computational and in vitro analyses of the antibacterial effect of the ethanolic extract of Pluchea indica L. leaves.

The most common gram-negative, Escherichia coli, and gram-positive bacteria, Bacillus spp., have evolved different mechanisms that have caused the emergence of multi-drug resistance. As a result, drugs that block the bacterial growth cycle are needed. Here, in silico and in vitro studies were performed to assess compounds in the Pluchea indica leaf extract, a medicinal plant, that can inhibit bacterial proteins. Briefly, P. indica leaves were extracted using ethanol. The crude extract was then subjected to gas chromatography-mass spectrometry for metabolite screening. Molecular docking simulations with rhomboid protease (Rpro) (Protein data bank ID number: 3ZMI from E. coli and filamenting temperature-sensitive mutant Z (FtsZ) protein data bank ID number: 2VAM from Bacillus subtilis were performed. Moreover, the well diffusion method was used to confirm the antibacterial activity of P. indica leaf extract. A total of 10 compounds were identified in the P. indica extract and used for computational analysis. Based on drug-likeness prediction, P. indica compounds may be drug-like molecules. Binding affinity tests indicated that 10,10-Dimethyl-2,6-dimethylenebicyclo(7.2.0)undecan-5.β.-ol and 11,11-Dimethyl-4,8-dimethylenebicyclo(7.2.0)undecan-3-ol had the most negative values. Accordingly, these compounds may be potential ligands that bind to bacterial proteins. The root mean square fluctuation values was <2 Å, indicating stable fluctuation binding for the ligand-protein complex. According to in vitro antibacterial assays, a high concentration (50%) of the P. indica extract markedly inhibited E. coli and B. subtilis, with inhibitory zone diameters of 31.86±1.63 and 21.09±0.09 mm, respectively. Overall, the compounds in the P. indica leaf extract were identified as functional inhibitors of E. coli and B. subtilis proteins via in silico analysis. This may facilitate development of antibacterial agents.

Codelivery of methotrexate and silibinin by niosome nanoparticles for enhanced chemotherapy of CT26 colon cancer cells

Colon cancer (CC) is one of the most prevalent cancers in the world, and chemotherapy is widely applied to combat it. However, chemotherapy drugs have severe side effects and emergence of multi drug resistance (MDR) is common. This bottleneck can be overcome by niosome nanocarriers that minimize drug dose/toxicity meanwhile allow co-loading of incompatible drugs for combination therapy. In this research, silibinin (Sil) as a hydrophobic drug was loaded into the lipophilic part, and methotrexate (MTX) into the hydrophilic part of niosome by the thin film hydration (TFH) method to form Nio@MS NPs for CT26 colon cancer therapy in vitro. Our results indicated synthesis of ideal niosome nanoparticles (NPs) with spherical morphology, size of ∼100 nm, and a zeta potential of −10 mV. The IC50 value for Nio@MS was determined ∼2.6 µg ml−1, which was significantly lower than MTX-Sil (∼6.86 µg ml−1), Sil (18.46 µg ml−1 ), and MTX (9.8 µg ml−1 ). Further, Nio@MS significantly reduced cell adhesion density, promoted apoptosis and increased gene expression level of caspase 3 and BAX while promoted significant downregulation of BCL2. In conclusion, the design and application of niosome to co-administer Sil and MTX can increase the drugs cytotoxicity, reduce their dose and improve anti-cancer potential by combating MDR.

Secondary metabolite profile of Streptomyces spp. changes when grown with the sub-lethal concentration of silver nanoparticles: possible implication in novel compound discovery.

The decline of new antibiotics and the emergence of multidrug resistance in pathogens necessitates a revisit of strategies used for lead compound discovery. This study proposes to induce the production of bioactive compounds with sub-lethal concentrations of silver nanoparticles (Ag-NPs). A total of Forty-two Actinobacteria isolates from four Saudi soil samples were grown with and without sub-lethal concentration of Ag-NPs (50µgml-1). The spent broth grown with Ag-NPs, or without Ag-NPs were screened for antimicrobial activity against four bacteria. Interestingly, out of 42 strains, broths of three strains grown with sub-lethal concentration of Ag-NPs exhibit antimicrobial activity against Staphylococcus aureus and Micrococcus luteus. Among these, two strains S4-4 and S4-21 identified as Streptomyces labedae and Streptomyces tirandamycinicus based on 16S rRNA gene sequence were selected for detailed study. The change in the secondary metabolites profile in the presence of Ag-NPs was evaluated using GC-MS and LC-MS analyses. Butanol extracts of spent broth grown with Ag-NPs exhibit strong antimicrobial activity against M. luteus and S. aureus. While the extracts of the controls with the same concentration of Ag-NPs do not show any activity. GC-analysis revealed a clear change in the secondary metabolite profile when grown with Ag-NPs. Similarly, the LC-MS patterns also differ significantly. Results of this study, strongly suggest that sub-lethal concentrations of Ag-NPs influence the production of secondary metabolites by Streptomyces. Besides, LC-MS results identified possible secondary metabolites, associated with oxidative stress and antimicrobial activities. This strategy can be used to possibly induce cryptic biosynthetic gene clusters for the discovery of new lead compounds.

Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice

Abstract. Ngemenya MN, Itoe LO, Awah LA, Asongana R, Ndip RA. 2024. Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice. Asian J Nat Prod Biochem 22: 43-50. The emergence of multidrug resistance has significantly compromised the treatment of Salmonella infections. The anti-Salmonella activity, toxicity, and biochemical effects of Moringa oleifera Lam. leaf crude extracts were studied by disc diffusion and microdilution against Multidrug-Resistant (MDR) strains. Cytotoxicity was investigated on monkey kidney epithelial cells (LLCMK2) and acute toxicity in BALB/c mice. Both hexane (MOHEX) and methanol (MOMET) extracts produced small zones of inhibition of 8mm at 1 mg and 2 mg per disc, indicating weak activity, but the minimum inhibitory concentration showed high (0.0625 mg/mL) to low activity (10 mg/mL) activity. No minimum bactericidal concentration was recorded at the concentrations tested. The 50% cytotoxic concentration (CC50) for methanol and hexane extracts were 2524 µg/mL and 5004 µg/mL, respectively, indicating a low risk of toxicity. No mortality or adverse effects were recorded in the acute toxicity test. Both extracts had no significant effects (p &lt; 0.05) on renal function and one liver enzyme (alanine aminotransferase), but MOMET significantly increased aspartate aminotransferase (p = 0.04), suggesting possible liver toxicity. The study shows that M. oleifera leaves possess bacteriostatic activity against multidrug-resistant Salmonella and are non-toxic; hence, it is a potential alternative treatment against multidrug-resistant Salmonella. Further studies of fractions and pure natural products of the extracts should be pursued.

Characterization of Salmonella phage of the genus Kayfunavirus isolated from sewage infecting clinical strains of Salmonella enterica.

The emergence of multi-drug resistance in Salmonella, causing food-borne infections, is a significant issue. With over 2,600 serovars in in Salmonella sp., it is crucial to identify specific solutions for each serovar. Phage therapy serves as an alternate treatment option. In this study, vB_SalP_792 phage was obtained from sewage, forming plaques in eight out of 13 tested clinical S. enterica isolates. Transmission electron microscopy (TEM) examination revealed a T7-like morphotype. The phage was characterized by its stability, life cycle, antibiofilm, and lytic ability in food sources. The phage remains stable throughout a range of temperatures (-20 to 70°C), pH levels (3-11), and in chloroform and ether. It also exhibited lytic activity within a range of MOIs from 0.0001 to 100. The life cycle revealed that 95% of the phages attached to their host within 3 min, followed by a 5-min latent period, resulting in a 50 PFU/cell burst size. The vB_SalP_792 phage genome has a dsDNA with a length of 37,281 bp and a GC content of 51%. There are 42 coding sequences (CDS), with 24 having putative functions and no resistance or virulence-related genes. The vB_SalP_792 phage significantly reduced the bacterial load in the established biofilms and also in egg whites. Thus, vB_SalP_792 phage can serve as an effective biocontrol agent for preventing Salmonella infections in food, and its potent lytic activity against the clinical isolates of S. enterica, sets out vB_SalP_792 phage as a successful candidate for future in vivo studies and therapeutical application against drug-resistant Salmonella infections.

Antimicrobial combination effects against multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa strains: A cross-sectional study.

Emergence of multidrug resistance in non-fermenting Gram-negative bacilli is a threat to public health. Combination therapy is a strategy for the treatment of antibiotic-resistant infections. In this cross-sectional study, a total of 63 nonduplicate clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosawere collected from various specimens. Identification of bacterial isolates was performed by phenotypic and molecular tests. Antibiotic susceptibility patterns and detection of β-lactamase genes were determined using the broth microdilution and polymerase chain reaction (PCR) techniques, respectively. Then, the combined effects analysis was determined by the checkerboard method. Based on the status of resistance to carbapenems (imipenem and meropenem), 25 isolates of each genus were selected for further investigation. For A. baumannii, bla OXA-23, bla OXA-58, and bla OXA-48 genes were positive in 21 (84%), 17 (68%), and 11 (44%) of isolates, respectively. In P. aeruginosa isolates, bla VIM was the most common gene (44%) and other genes including bla IMP, bla NDM, and bla OXA-23 were found in nine (36%), six (24%), and three (12%) isolates, respectively. Meropenem (MER)-tigecycline (TIG) had a significant synergistic effect against 20 (80%) A. baumannii (pvalue < 0.001). This combination was also efficient against 5 (20%) P. aeruginosa isolates. Moreover, the other combination, tigecycline-amikacin (TIG-AMK) was effective against 10 (40%) A. baumannii isolates. The combination of colistin (COL) and MER showed a significant synergistic effect against 21 (84%) A. baumannii (pvalue < 0.001) and 17 (68%) P. aeruginosa isolates (pvalue < 0.001). The MER-TIG and COL-MER combinations are promising options against resistant bacteria. Our study could be helpful for the development of a new treatment recommendation.

Strategic implementation of upflow microbubble airlift photocatalytic process to control heavy metal resistant-MDR bacteria and the associated genes in wastewater

The emergence of multidrug resistance (MDR) and heavy metal resistance (HMR) in bacterial pathogens and genes through mobile genetic elements (MGEs) from wastewater effluents needs to be eradicated using green technology. HMR is critical to controlling antimicrobial resistance but has been neglected in most photocatalytic disinfection (PCD) studies. Advanced photocatalysis in antimicrobial studies requires a strategic approach to enhance the disinfection efficiency. This study applied an optimized upflow airlift photocatalytic reactor (UAPR) with microbubble air and blue light to remove the antimicrobial resistance (HMR–MDR bacteria (HMR–MDRB), HMR genes (HMRGs), antibiotic resistant genes (ARGs) and MGEs) and inhibit pathogenicity in a mixed culture of high-strength HMR–MDRB isolated from wastewater. Stable dissolved oxygen (DO) supplementation and blue light significantly affected the HMRGs and MGE reduction, resulting in enhanced disinfection activity (30 %) and reaction time (60 min) required for the complete inactivation of HMR-MDRB mixed culture. The process effectively reduced the blaNDM-1 (3.37 log), pbrT (2.18 log), intl1 (2.16 log), and tn916/1545 (4.07 log), with a PCD rate constant (kg) of 0.0515 min−1, 0.0359 min−1, 0.0292 min−1, and 0.0662 min−1, respectively. Process mechanism studies showed that the stable supplementation of DO was a critical factor in controlling the type of reactive oxygen species (ROS), resulting in type II ROS, 1O2, as the critical free radical contributing to the reduction of ARGs and integron, whereas h+ was the ROS for pbrT and transposon.

Acquired resistance or tolerance? – in search of mechanisms underlying changes in the resistance profile of Candida albicans and Candida parapsilosis as a result of exposure to methotrexate

The increasing prevalence of fungal strains showing acquired resistance and multidrug resistance is an increasing therapeutic problem, especially in patients with a severely weakened immune system and undergoing chemotherapy. What is also extremely disturbing is the similarity of the resistance mechanisms of fungal cells and other eukaryotic cells, including human cells, which may contribute to the development of cross-resistance in fungi in response to substances used in e.g. anticancer treatment. An example of such a drug is methotrexate, which is pumped out of eukaryotic cells by ABC transmembrane transporters - in fungi, used to remove azoles from fungal cells.For this reason, the aim of the study was to analyze the expression levels of genes: ERG11, MDR1 and CDR1, potentially responsible for the occurrence of cross-resistance in Candida albicans and Candida parapsilosis as a result of fungal exposure to methotrexate (MTX).In vitro exposure of C. albicans and C. parapsilosis strains to methotrexate showed a high increase in resistance to fluconazole and a partial increase in resistance to voriconazole. Analysis of the expression of resistance genes showed varied responses of the tested strains depending on the species. In the case of C. albicans, an increase in the expression of the MDR1 gene was observed, and a decrease in ERG11 and CDR1. However, for C. parapsilosis there was an increase in the expression of the CDR1 gene and a decrease in ERG11 and MDR1.We noted the relationship between the level of resistance to voriconazole and the level of ERG11 gene expression in C. albicans. This indicates that this type of relationship is different for each species. Our research confirms that the mechanisms by which fungi acquire resistance and develop cross-resistance are highly complex and most likely involve several pathways simultaneously. The emergence of multidrug resistance may be related to the possibility of developing tolerance to antimycotics by fungi.

Comprehensive analysis of multiple cytokines to stratify uropathogenic Escherichia coli pathogenesis in mouse model of urinary tract infection

PurposeUrinary tract infection (UTI) is one of the most common human bacterial infections primarily caused by uropathogenic E. coli (UPEC). Empiric treatment in UTI cause emergence of multidrug resistance and limit treatment options. Understanding UTI at the molecular level with respect to the causative pathogen as well as subsequent host response pose an absolute necessity towards appropriate clinical management. This study aimed to investigate host cytokine response in mouse UTI model with respect to bacterial colonization and associated virulence gene expression upon infection. MethodMouse UTI model was established with two clinical UPEC isolates E. coli NP105 and E. coli P025. UPEC colonization in bladder and kidney was evaluated by bacterial culture (CFU/ml). Histopathology of the tissues were examined by hematoxylin and eosin staining. PCR and real time PCR were used to detect the incidence and expression of respective bacterial genes. Cytokine concentrations in tissues and sera were evaluated using ELISA. GraphPad prism version 8.0.2 was used for statistical interpretation. ResultHighest bacterial colonization was observed on 7th and 9th day post infection (p.i). in bladder and kidney of mouse infected with E. coli P025 and E. coli NP105 respectively with a distinct difference in relative expression of fimH and papC adhesin genes in vivo. IL-1β level in tissues and sera of E. coli NP105 and E. coli P025 infected mouse was significantly different but the IL-17A, GCSF, TGF-β levels were comparable. ConclusionThese findings show a role of IL1β to stratify pathogenicity of UPEC in mouse UTI model.

Insights into the anti-Candida albicans properties of natural phytochemicals: An in vitro and in vivo investigation.

Invasive candidiasis, attributed to Candida albicans, has long been a formidable threat to human health. Despite the advent of effective therapeutics in recent decades, the mortality rate in affected patient populations remains discouraging. This is exacerbated by the emergence of multidrug resistance, significantly limiting the utility of conventional antifungals. Consequently, researchers are compelled to continuously explore novel solutions. Natural phytochemicals present a potential adjunct to the existing arsenal of agents. Previous studies have substantiated the efficacy of phytochemicals against C. albicans. Emerging evidence also underscores the promising application of phytochemicals in the realm of antifungal treatment. This review systematically delineates the inhibitory activity of phytochemicals, both in monotherapy and combination therapy, against C. albicans in both in vivo and in vitro settings. Moreover, it elucidates the mechanisms underpinning the antifungal properties, encompassing (i) cell wall and plasma membrane damage, (ii) inhibition of efflux pumps, (iii) induction of mitochondrial dysfunction, and (iv) inhibition of virulence factors. Subsequently, the review introduces the substantial potential of nanotechnology and photodynamic technology in enhancing the bioavailability of phytochemicals. Lastly, it discusses current limitations and outlines future research priorities, emphasizing the need for high-quality research to comprehensively establish the clinical efficacy and safety of phytochemicals in treating fungal infections. This review aims to inspire further contemplation and recommendations for the effective integration of natural phytochemicals in the development of new medicines for patients afflicted with C. albicans.

Attenuation of Las/Rhl quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 by Artocarpesin

The emergence of multidrug resistance and increased pathogenicity in microorganisms is conferred by the presence of highly synchronized cell density dependent signalling pathway known as quorum sensing (QS). The QS hierarchy is accountable for the secretion of virulence phenotypes, biofilm formation and drug resistance. Hence, targeting the QS phenomenon could be a promising strategy to counteract the bacterial virulence and drug resistance. In the present study, artocarpesin (ACN), a 6-prenylated flavone was investigated for its capability to quench the synthesis of QS regulated virulence factors. From the results, ACN showed significant inhibition of secreted virulence phenotypes such as pyocyanin (80%), rhamnolipid (79%), protease (69%), elastase (84%), alginate (88%) and biofilm formation (88%) in opportunistic pathogen, Pseudomonas aeruginosa PAO1. Further, microscopic observation of biofilm confirmed a significant reduction in biofilm matrix when P. aeruginosa PAO1 was supplemented with ACN at its sub-MIC concentration. Quantitative gene expression studies showed the promising aspects of ACN in down regulation of several QS regulatory genes associated with production of virulence phenotypes. Upon treatment with sub-MIC of ACN, the bacterial colonization in the gut of Caenorhabditis elegans was potentially reduced and the survival rate was greatly improved. The promising QS inhibition activities were further validated through in silico studies, which put an insight into the mechanism of QS inhibition. Thus, ACN could be considered as possible drug candidate targeting chronic microbial infections.

Detection of Multidrug-Resistant Integrons Associated with Acinetobacter baumannii Isolated from Clinical and Environmental Samples

The emergence of multidrug resistance (MDR) among pathogenic bacteria is a root cause of severe infections. It is threatening to observe that MDR is also found in ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens, which has caused a hike in nosocomial infection. The diminishing spectrum of treatment against these pathogens demands an alternative realm of treatment. One such nosocomial pathogen, Acinetobacter baumannii is known to cause pneumonia, blood stream infection, urinary tract infections, especially affecting immunocompromised individuals. Due to indiscriminate use of antibiotics, these pathogens have gained resistance to major classes of antibiotics through mutation and horizontal gene transfer via mobile genetic elements such as plasmids, transposons and integrons. This study mainly aims at identifying integron mediated drug resistance among clinical and environmental strains of A. baumannii. In this study, A. baumannii strains isolated from clinical and environmental samples were screened for antibiotic susceptibility tests. The multidrug resistant isolates were then checked for the presence of 3 classes of integrons viz Intl1 (Class 1), Intl2 (class 2) and, Intl3 (class 3). The integron region of the positive isolates was sequenced, and the drug-resistance gene cassettes were identified. All the clinical and environmental isolates were multidrug resistant. Three clinical isolates of A. baumannii showed positive amplification to Intl1 at 2kb, while none of the environmental isolates carried integrons, though they were multidrug resistant. The sequencing of the integron region of clinical isolates revealed the presence of three antibiotic resistance genes within the integron that encode resistance to chloramphenicol, rifampin, and aminoglycoside. This study prominently highlights the presence of class 1 integrons carrying different antimicrobial resistance determinants among A. baumannii isolated from clinical samples.

Multidrug resistance of Botrytis cinerea associated with its adaptation to plant secondary metabolites.

Fungicides are an effective way to control gray mold of grapes, but the pathogen Botrytis cinerea can develop resistance, overcoming the effectiveness of a fungicide that is repeatedly applied. More importantly, the emergence of multidrug resistance (MDR) in the field, where multiple fungicides with different modes of action simultaneously lose their efficacies, is a significant concern. MDR is associated with ATP-binding cassette (ABC) transporters of the pathogen, and certain plant secondary metabolites (PSMs) stimulate the upregulation of ABC transporters, we hypothesized that the pathogen's preadaptation to PSMs might contribute to MDR development. To test this in B. cinerea, ten PSMs, namely, resveratrol, reserpine, chalcone, flavanone, eugenol, farnesol, anethene, camptothecin, salicylic acid, and psoralen, were selected based on their association with ABC transporters involved in fungicide resistance. B. cinerea strain B05.10 was continuously transferred for 15 generations on potato dextrose agar amended with a PSM (PDAP), and sensitivities to PSMs and fungicides were examined on the 5th, 10th, and 15th generations. RNA was extracted from B. cinerea from the selected generations. After 15 generations of culture transfers, an up-regulation was observed in the expression of ABC transporter-encoding genes BcatrB, BcatrD, and BcatrK using quantitative polymerase chain reaction (qPCR). This upregulation was found to contribute to MDR of B. cinerea against two or more fungicides, among azoxystrobin, boscalid, fludioxonil, difenoconazole, prochloraz, and pyrimethanil. This finding was confirmed through genetic transformation. The decreased sensitivity of B. cinerea to fungicides was confirmed as a subsequent MDR phenotype after exposure to camptothecin, flavanone, and resveratrol. Besides, transcriptome analysis also revealed the upregulation of transcription factors related to ABC expression following resveratrol exposure. This suggests that PSMs contributed to inducing preadaptation of B. cinerea, leading to subsequent MDR.IMPORTANCEThe emergence of MDR in plant pathogens is a threat to plant disease management and leads to the use of excessive fungicides. Botrytis cinerea is of particular concern because its MDR has widely emerged in the field. Understanding its genesis is the first step for controlling MDR. In this study, the contribution of PSMs to MDR has been examined. Effective management of this pathogen in agroecosystems relies on a better understanding of how it copes with phytochemicals or fungicides.

Study of bacteriological profile and antibiotic susceptibility pattern of pus isolates in tertiary care hospital

Surgical wound causes invasion of pathogens causing surgical site infections which are commonly polymicrobial in nature. This pus forming infection causes delayed wound healing, wound dehiscence and wound breakdown contributing to important healthcare associated infections (HAI) Multidrug resistance has emerged among organisms isolated in pus sample due to failure of appropriate use of antibiotics.: 1. To study the bacteriological profile of pus samples 2. To determine the antibiotic susceptibility pattern of isolated pathogens from pus samples.The study was conducted in department of microbiology, Shimoga institute of medical sciences, Shimoga from January 2018 to June 2018.All pus samples were processed on blood agar, MacConkey agar and incubated at 37°c under aerobic conditions for 24 hours. The organisms were identified as per standard conventional methods. The antimicrobial susceptibility tests were done by Kirby–Bauer’s Disk Diffusion method on Mueller–Hinton Agar and interpreted as per clinical laboratory standard institution guidelines (CLSI). Out of 350 samples 250 were culture positive 100 were culture negative. Among culture positive most common organism isolated was followed by 86(34.45%), 72(28.8%), 55(22%), 20(8%), 9(3.6%), 2(0.8%), 3(1.2%) 3(1.2%), 3(1.2%). Gram positive organisms were most sensitive for linezolid, vancomycin and least sensitive to cefoxitin, erythromycin. Gram Negative Organisms Were Most Sensitive for Imipenam, Piperacillin tazobactam and least Sensitive for Ampicillin-sulbactam, Ciprofloxacin is most common etiology of pus forming infection most importantly surgical site infections (SSI). MRSA prevalence in hospital set up indicates the failure of proper infection control practices implementation in the hospitals causing healthcare associated infections (HAI). Emergence of multidrug resistance among the pus isolates is because of non-judicious use of antibiotics.