Candida genus yeast resistance to antifungals

Candida genus species are opportunistic fungi causing candidiasis, whose prevalence ison a growing trend. C. albicans is the commonest yeast causing opportunistic fungal diseases inhumans, whose pleomorphism, highly adaptability and biofilm formation are essential for itsvirulence and pathogenicity. Other remarkable species are C. glabrata and the emergentmultidrug resistant C. auris.Main antifungals used for treatment of invasive candidiasis are azoles, whose target is14α-lanosterol demethylase; polyenes, that target ergosterol; pyrimidine analogues, whichinhibit DNA and RNA biosynthesis; and echinocandins, inhibiting β-(1,3)-glucan synthase. Aninappropriate usage or prolonged exposure to these toxic compounds have developed theemergence of multidrug resistance phenomenon. One of the most prominent mechanisms ofantifungal resistance in Candida genus is the rapid efflux of incoming drugs via active transport,due to the overexpression of two main classes of plasma membrane efflux pumps: ABC andMFS transporters. In addition, entry constraints, genomic alterations and cell plasticity are othermechanisms of the resistance.Owing to the alarming life-threatening infections caused by Candida spp., severalstrategies have been found to reduce drug resistance. Some of them are the structure-baseddesign of effective inhibitors of efflux, chemosensitization and design of new antifungal drugs.An effective antifungal stewardship programme and further investigation are urgently needed tocircumvent the menace of multidrug resistance.<br /

Study of Multidrug Resistance in Environmental Microorganisms

El reino Procariota constituye la forma de vida más abundante y omnipresente. El contacto constante de las bacterias ambientales con los seres humanos, les ha permitido desarrollar numerosos mecanismos para protegerse de nuestros productos. De esta manera, las bacterias comunes y no patogénicas, que normalmente se encuentran en productos de uso diario, pueden presentar multirresistencia a los antibióticos. Durante nuestra investigación, nos centraremos en las bacterias obtenidas de diferentes muestras ambientales, que tienen en común que son inocuas y Gram-negativas. Se sugiere que todos ellas muestran resistencia a los antibióticos utilizados, el tipo de resistencia que da la presencia de bombas de flujo. Estas bombas son responsables de expulsar los compuestos patógenos a fuera de la célula, antes de que puedan dañar la bacteria. Para probar nuestras hipótesis, se estudiará la concentración inhibitoria mínima para los antibióticos tetraciclina y cloranfenicol, así como el potencial de membrana bacteriana contra el antibiótico polimixina B. El desarrollo de estos experimentos ha permitido obtener un resultado claro: una gran parte de las bacterias estudiadas tienen la resistencia antibiótica esperada. También se ha comprobado que algunas de ellas son capaces de resistir la presencia de los tres antibióticos utilizados, resultando ser bacterias multirresistentes. Sin embargo, se han realizado un pequeño número de experimentos, sin tener en cuenta todas las bacterias en cada uno de ellos. La falta de resultados comparativos impide obtener una visión más amplia del asunto. Más estudios, más detallados y teniendo en cuenta la información obtenida en este presente, serán necesarios para obtener conclusiones más sólidas.<br /

Biochemijos studijų problemos Vytauto Didžiojo universitete

Biochemijos katedraVytauto Didžiojo universiteta

Synthesis and efficiency evaluation of RND type efflux pump inhibitors

Salmonella enterica serovar Typhimurium is the main cause of food poisoning and is the second most common cause of bacterial diarrhea. RND-type multidrug resistance efflux pumps are the main reason of Salmonella enterica cell resistance to antibiotics. It is important to investigate the mechanism of efflux pump inhibition. The aim of our work was to synthesize small dipeptide inhibitors and to evaluate the efficiency RND-type efflux pump inhibition in S. enterica cells. In this work we present data on the electrochemical assay of accumulation of an indicator compound of efflux pumps in bacteria tetraphenylphosphonium (TPP⁺) ions. We studied effects of the synthesized RND-type efflux pump inhibitors on accumulation of TPP⁺ ions in S. enterica. Data on the effective concentrations of the inhibitors and the efficiency of inhibition of RND-type efflux pump activity will be presentedBiochemijos katedraVytauto Didžiojo universiteta

Monitoring of energy-dependent efflux in Candida albicans

Patients with AIDS and those who are undergoing chemotherapeutic modalities are always at a risk of developing C. albicans infections. Morbidity and mortality from invasive candidiasis and candidemia have increased significantly over the last four decades. The scientific and clinical findings have shown that the incidence of severe Candida infections is constantly increasing. With the development of azoles and other antifungal medicines, the potential for treatment of these infections has improved significantly. However, the possibility of timely diagnosis of fungal infections is limited, and therefore the outcome of the disease is not favorable. The pivotal membrane transporters that C. albicans is exploiting as one of the strategies to develop multidrug resistance (MDR), belong to either the ATP binding cassette (ABC) or the major facilitator superfamily (MFS) classes of efflux pumps. Overexpression of the efflux pumps Cdr1p, Cdr2p and Mdr1p is the main mechanism of fluconazole resistance in C. albicans. For studies of yeast efflux activity we applied electrochemical measurements of phenyldicarbaundeborane (PCB-) ions in incubation medium. To activate the MDR pumps C. albicans wild-type cells were cultivated with fluconazole. During experiments in arsenate buffer, where the cells rapidly lose ATP, an additional binding of PCB- is observed. This indicates the suspended activity of cellular MDR pumps due to the lack of energy. No additional accumulation of PCB- was observed in experiments with control cells grown without fluconazole. Using this assay method different C. albicans isolates were investigated and the results of this study will be presented at the conferenceBiochemijos katedraGamtos mokslų fakultetasVytauto Didžiojo universiteta

Synthesis of RND-type efflux pumps inhibitor phenylalanyl-arginyl-B-naphthylamide

Biochemijos katedraVytauto Didžiojo universiteta

Reason of multidrug resistance in MX-1 cell cultures

Background. Multidrug resistance (MDR) is cancer cells simultaneous resistance to many drugs used for chemotherapy. MDR efflux pumps is one of the main molecular mechanisms responsible for this type of cell resistance [1]. In this study we explored activity of the efflux pumps in wild-type and our derived mutant cell sublines. The aim: to assay the efficiency of MDR pumps in MX-1 cells. Methods. The levels of MX-1 cell resistance to doxorubicin (DOX), ethidium (Et+), monensin (Mon) and nigericin (Nig) were estimated using MTT viability test. The stability of MX- cell resistance to TPP+ were estimated also using MTT viability test. Results. In this study a subline of tetraphenylphosphonium (TPP+)-resistant MX-1 cells was developed. These cells were more resistant also to DOX about 500, ethidium bromide - 16, Mon - 130 and Nig – 170 times. The resistance to TPP+ remained after three days cultivation without TPP+. Conclusion. Cell of MX-1TPP+ subline was more resistant to DOX, Et+, Mon and Nig. Moreover the resistance to TPP+ was detected after three days cultivation without TPP+Biochemijos katedraVytauto Didžiojo universiteta