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Sample records for antifungal drug resistance

  1. Antifungal drugs and resistance: Current concepts

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    Pramod Kumar Nigam

    2015-04-01

    Full Text Available Recently, clinical failure and relapses have been observed in patients treated with antifungals. Drug resistance has become an important problem leading to significant negative social, psychological, and occupational health effects and quality of life. Early recognition and treatment is essential to reduce morbidity and possibility of transmission. The increased use, inappropriate prescribing and over the counter sale of antifungal agents has also added in the development of resistance to these drugs. The main biochemical and molecular mechanisms that contribute to antifungal resistance include reduced uptake of the drug, an active transport out of the cell or modified drug metabolic degradation of the cell, changes in the interaction of the drug to the target site or other enzymes involved in the process by point mutations, overexpression of the target molecule, overproduction or mutation of the target enzyme, amplification and gene conversion (recombination, and increased cellular efflux and occurrence of biofilm. Although, there is considerable knowledge concerning the biochemical, genetic and clinical aspects of resistance to antifungal agents, expansion of our understanding of the mechanisms by which antifungal resistance emerges and spreads, quicker methods for the determination of resistance, targetting efflux pumps, especially ATP binding cassette (ABC transporters and heat shock protein 90, new drug delivery systems, optimizing therapy according to pharmacokinetic and pharmacodynamic characteristics, new classes of antifungal drugs that are active against azole-resistant isolates, and use of combinations of antifungal drugs or use of adjunctive immunostimulatory therapy and other modalities of treatment will clearly be important for future treatment strategies and in preventing development of resistance.

  2. Antifungal drugs and resistance: Current concepts

    OpenAIRE

    Pramod Kumar Nigam

    2015-01-01

    Recently, clinical failure and relapses have been observed in patients treated with antifungals. Drug resistance has become an important problem leading to significant negative social, psychological, and occupational health effects and quality of life. Early recognition and treatment is essential to reduce morbidity and possibility of transmission. The increased use, inappropriate prescribing and over the counter sale of antifungal agents has also added in the development of resistance to the...

  3. Antifungal Drug Resistance - Concerns for Veterinarians

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    Bharat B. Bhanderi

    2009-10-01

    Full Text Available In the 1990s, there were increased incidences of fungal infectious diseases in human population which might be due to increase in immunosuppressive diseases. But the major concern was increase in prevalence of resistance to antifungal drugs which were reported both in the fungal isolates of human beings and that of animal origin. In both animals and human beings, resistance to antimicrobial agents has important implications for morbidity, mortality and health care costs, because resistant strains are responsible for bulk of infection in animals and human beings, and large number of antimicrobial classes offers more diverse range of resistance mechanisms to study and resistance determinants move into standard well-characterized strains that facilitates the detailed study of molecular mechanisms of resistance in microorganisms. Studies on resistance to antifungal agents has been lagging behind that of antibacterial resistance for several reasons, the foremost reason might be fungal agents were not recognized as important animal and human pathogens, until relatively in recent past. But the initial studies of antifungal drug resistance in the early 1980s, have accumulated a wealth of knowledge concerning the clinical, biochemical, and genetic aspects of this phenomenon. Presently, exploration of the molecular aspects for antifungal drug resistance has been undertaken. Recently, the focus was on several points like developing a more detailed understanding of the mechanisms of antimicrobial resistance, improved methods to detect resistance when it occurs, methods to prevent the emergence and spread of resistance and new antimicrobial options for the treatment of infections caused by resistant organisms. [Vet. World 2009; 2(5.000: 204-207

  4. Targeting efflux pumps to overcome antifungal drug resistance.

    Science.gov (United States)

    Holmes, Ann R; Cardno, Tony S; Strouse, J Jacob; Ivnitski-Steele, Irena; Keniya, Mikhail V; Lackovic, Kurt; Monk, Brian C; Sklar, Larry A; Cannon, Richard D

    2016-08-01

    Resistance to antifungal drugs is an increasingly significant clinical problem. The most common antifungal resistance encountered is efflux pump-mediated resistance of Candida species to azole drugs. One approach to overcome this resistance is to inhibit the pumps and chemosensitize resistant strains to azole drugs. Drug discovery targeting fungal efflux pumps could thus result in the development of azole-enhancing combination therapy. Heterologous expression of fungal efflux pumps in Saccharomyces cerevisiae provides a versatile system for screening for pump inhibitors. Fungal efflux pumps transport a range of xenobiotics including fluorescent compounds. This enables the use of fluorescence-based detection, as well as growth inhibition assays, in screens to discover compounds targeting efflux-mediated antifungal drug resistance. A variety of medium- and high-throughput screens have been used to identify a number of chemical entities that inhibit fungal efflux pumps. PMID:27463566

  5. Update on antifungal drug resistance mechanisms of Aspergillus fumigatus.

    Science.gov (United States)

    Chamilos, G; Kontoyiannis, D P

    2005-12-01

    Although the arsenal of agents with anti-Aspergillus activity has expanded over the last decade, mortality due to invasive aspergillosis (IA) remains unacceptably high. Aspergillus fumigatus still accounts for the majority of cases of IA; however less susceptible to antifungals non-fumigatus aspergilli began to emerge. Antifungal drug resistance of Aspergillus might partially account for treatment failures. Recent advances in our understanding of mechanisms of antifungal drug action in Aspergillus, along with the standardization of in vitro susceptibility testing methods, has brought resistance testing to the forefront of clinical mycology. In addition, molecular biology has started to shed light on the mechanisms of resistance of A. fumigatus to azoles and the echinocandins, while genome-based assays show promise for high-throughput screening for genotypic antifungal resistance. Several problems remain, however, in the study of this complex area. Large multicenter clinical studies--point prevalence or longitudinal--to capture the incidence and prevalence of antifungal resistance in A. fumigatus isolates are lacking. Correlation of in vitro susceptibility with clinical outcome and susceptibility breakpoints has not been established. In addition, the issue of cross-resistance between the newer triazoles is of concern. Furthermore, in vitro resistance testing for polyenes and echinocandins is difficult, and their mechanisms of resistance are largely unknown. This review examines challenges in the diagnosis, epidemiology, and mechanisms of antifungal drug resistance in A. fumigatus. PMID:16488654

  6. Mechanisms of antifungal drug resistance in Candida dubliniensis.

    LENUS (Irish Health Repository)

    Coleman, David C

    2010-06-01

    Candida dubliniensis was first described in 1995 and is the most closely related species to the predominant human fungal pathogen Candida albicans. C. dubliniensis is significantly less prevalent and less pathogenic than C. albicans and is primarily associated with infections in HIV-infected individuals and other immunocompromised cohorts. The population structure of C. dubliniensis consists of three well-defined major clades and is significantly less diverse than C. albicans. The majority of C. dubliniensis isolates are susceptible to antifungal drugs commonly used to treat Candida infections. To date only two major patterns of antifungal drug resistance have been identified and the molecular mechanisms of these are very similar to the resistance mechanisms that have been described previously in C. albicans. However, significant differences are evident in the predominant antifungal drug mechanisms employed by C. dubliniensis, differences that reflect its more clonal nature, its lower prevalence and characteristics of its genome, the complete sequence of which has only recently been determined.

  7. Nationwide study of candidemia, antifungal use, and antifungal drug resistance in Iceland, 2000 to 2011.

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    Asmundsdottir, Lena Ros; Erlendsdottir, Helga; Gottfredsson, Magnus

    2013-03-01

    Candidemia is often a life-threatening infection, with highly variable incidence among countries. We conducted a nationwide study of candidemia in Iceland from 2000 to 2011, in order to determine recent trends in incidence rates, fungal species distribution, antifungal susceptibility patterns, and concurrent antifungal consumption. A total of 208 infection episodes in 199 patients were identified. The average incidence during the 12 years was 5.7 cases/100,000 population/year, which was significantly higher than that from 1990 to 1999 (4.3/100,000/year; P = 0.02). A significant reduction in the use of blood cultures was noted in the last 3 years of the study, coinciding with the economic crisis in the country (P 60 years, and varied by gender. Age-specific incidence among males >80 years old was 28.6/100,000/year, and it was 8.3/100,000/year for females in this age group (P = 0.028). The 30-day survival rate among adult patients remained unchanged compared to that from 1990 to 1999 (70.4% versus 69.5%, P = 0.97). Candida albicans was the predominant species (56%), followed by C. glabrata (16%) and C. tropicalis (13%). The species distribution remained stable compared to that from previous decades. Fluconazole use increased 2.4-fold from 2000 to 2011, with no increase in resistance. In summary, the incidence of candidemia in Iceland has continued to increase but may have reached a steady state, and no increase in antifungal drug resistance has been noted. Decreased use of blood cultures toward the end of the study may have influenced detection rates.

  8. Ergosterol biosynthesis in Aspergillus fumigatus: its relevance as an antifungal target and role in antifungal drug resistance

    OpenAIRE

    Alcazar-Fuoli, Laura; Mellado, Emilia

    2013-01-01

    Ergosterol, the major sterol of fungal membranes, is essential for developmental growth and the main target of antifungals that are currently used to treat fatal fungal infections. Emergence of resistance to existing antifungals is a current problem and several secondary resistance mechanisms have been described in Aspergillus fumigatus clinical isolates. A full understanding of ergosterol biosynthetic control therefore appears to be essential for improvement of antifungal efficacy and to pre...

  9. Exploring azole antifungal drug resistance in Aspergillus fumigatus with special reference to resistance mechanisms

    NARCIS (Netherlands)

    Chowdhary, A.; Sharma, C.; Hagen, F.; Meis, J.F.G.M.

    2014-01-01

    Aspergillus fumigatus, a ubiquitously distributed opportunistic pathogen, is the global leading cause of aspergillosis. Azole antifungals play an important role in the management of aspergillosis. However, over a decade, azole resistance in A. fumigatus isolates has been increasingly reported with v

  10. Effectiveness of Posaconazole in Recalcitrant Fungal Keratitis Resistant to Conventional Antifungal Drugs

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    A. Altun

    2014-01-01

    Full Text Available Purpose. To present the success of posaconazole in two cases with recalcitrant fugal keratitis that were resistant to conventional antifungal drugs. Method. We presented two cases that were treated with posaconazole after the failure of fluconazole or voriconazole, amphotericin B, and natamycin therapy. Case 1 was a 62-year-old man with a history of ocular trauma. He had been using topical fluorometholone and tobramycin. His best corrected visual acuity (BCVA was hand motion. He had 5.0 × 4.5 mm area of deep corneal ulcer with stromal infiltration. Case 2 was a 14-year-old contact lens user. He had been using topical moxifloxacin, tobramycin, and cyclopentolate. His BCVA was 20/200. He had a 4.0 × 3.0 mm area of pericentral corneal ulcer with deep corneal stromal infiltration and 2 mm hypopyon. Results. Both patients initially received systemic and topical fluconazole or voriconazole and amphotericin B and topical natamycin that were all ineffective. But the response of posaconazole was significant. After posaconazole, progressive improvement was seen in clinical appearance. BCVA improved to 20/100 in case 1 and 20/40 in case 2. Conclusion. Posaconazole might be an effective treatment option for recalcitrant fusarium keratitis and/or endophthalmitis resistant to conventional antifungal drugs.

  11. The synthesis and synergistic antifungal effects of chalcones against drug resistant Candida albicans.

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    Wang, Yuan-Hua; Dong, Huai-Huai; Zhao, Fei; Wang, Jie; Yan, Fang; Jiang, Yuan-Ying; Jin, Yong-Sheng

    2016-07-01

    To identify effective and low toxicity synergistic antifungal compounds, 24 derivatives of chalcone were synthesized to restore the effectiveness of fluconazole against fluconazole-resistant Candida albicans. The minimal inhibitory concentration (MIC80) and the fractional inhibitory concentration index (FICI) of the antifungal synergist fluconazole were measured against fluconazole-resistant Candida albicans. This was done via methods established by the clinical and laboratory standards institute (CLSI). Of the synthesized compounds, 2'-hydroxy-4'-methoxychalcone (8) exhibited the most potent in vitro (FICI=0.007) effects. The structure activity relationship of the compounds are then discussed. PMID:27210436

  12. Emerging Threats in Antifungal-Resistant Fungal Pathogens

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    Sanglard, Dominique

    2016-01-01

    The use of antifungal drugs in the therapy of fungal diseases can lead to the development of antifungal resistance. Resistance has been described for virtually all antifungal agents in diverse pathogens, including Candida and Aspergillus species. The majority of resistance mechanisms have also been elucidated at the molecular level in these pathogens. Drug resistance genes and genome mutations have been identified. Therapeutic choices are limited for the control of fungal diseases, and it is ...

  13. Yeasts acquire resistance secondary to antifungal drug treatment by adaptive mutagenesis.

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    David Quinto-Alemany

    Full Text Available Acquisition of resistance secondary to treatment both by microorganisms and by tumor cells is a major public health concern. Several species of bacteria acquire resistance to various antibiotics through stress-induced responses that have an adaptive mutagenesis effect. So far, adaptive mutagenesis in yeast has only been described when the stress is nutrient deprivation. Here, we hypothesized that adaptive mutagenesis in yeast (Saccharomyces cerevisiae and Candida albicans as model organisms would also take place in response to antifungal agents (5-fluorocytosine or flucytosine, 5-FC, and caspofungin, CSP, giving rise to resistance secondary to treatment with these agents. We have developed a clinically relevant model where both yeasts acquire resistance when exposed to these agents. Stressful lifestyle associated mutation (SLAM experiments show that the adaptive mutation frequencies are 20 (S. cerevisiae -5-FC, 600 (C. albicans -5-FC or 1000 (S. cerevisiae--CSP fold higher than the spontaneous mutation frequency, the experimental data for C. albicans -5-FC being in agreement with the clinical data of acquisition of resistance secondary to treatment. The spectrum of mutations in the S. cerevisiae -5-FC model differs between spontaneous and acquired, indicating that the molecular mechanisms that generate them are different. Remarkably, in the acquired mutations, an ectopic intrachromosomal recombination with an 87% homologous gene takes place with a high frequency. In conclusion, we present here a clinically relevant adaptive mutation model that fulfils the conditions reported previously.

  14. Antifungal drug discovery: the process and outcomes.

    Science.gov (United States)

    Calderone, Richard; Sun, Nuo; Gay-Andrieu, Francoise; Groutas, William; Weerawarna, Pathum; Prasad, Sridhar; Alex, Deepu; Li, Dongmei

    2014-01-01

    New data suggest that the global incidence of several types of fungal diseases have traditionally been under-documented. Of these, mortality caused by invasive fungal infections remains disturbingly high, equal to or exceeding deaths caused by drug-resistant tuberculosis and malaria. It is clear that basic research on new antifungal drugs, vaccines and diagnostic tools is needed. In this review, we focus upon antifungal drug discovery including in vitro assays, compound libraries and approaches to target identification. Genome mining has made it possible to identify fungal-specific targets; however, new compounds to these targets are apparently not in the antimicrobial pipeline. We suggest that 'repurposing' compounds (off patent) might be a more immediate starting point. Furthermore, we examine the dogma on antifungal discovery and suggest that a major thrust in technologies such as structural biology, homology modeling and virtual imaging is needed to drive discovery. PMID:25046525

  15. The dual role of candida glabrata drug:H+ antiporter CgAqr1 (ORF CAGL0J09944g) in antifungal drug and acetic acid resistance.

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    Costa, Catarina; Henriques, André; Pires, Carla; Nunes, Joana; Ohno, Michiyo; Chibana, Hiroji; Sá-Correia, Isabel; Teixeira, Miguel C

    2013-01-01

    Opportunistic Candida species often have to cope with inhibitory concentrations of acetic acid, in the acidic environment of the vaginal mucosa. Given that the ability of these yeast species to tolerate stress induced by weak acids and antifungal drugs appears to be a key factor in their persistence and virulence, it is crucial to understand the underlying mechanisms. In this study, the drug:H(+) antiporter CgAqr1 (ORF CAGL0J09944g), from Candida glabrata, was identified as a determinant of resistance to acetic acid, and also to the antifungal agents flucytosine and, less significantly, clotrimazole. These antifungals were found to act synergistically with acetic acid against this pathogen. The action of CgAqr1 in this phenomenon was analyzed. Using a green fluorescent protein fusion, CgAqr1 was found to localize to the plasma membrane and to membrane vesicles when expressed in C. glabrata or, heterologously, in Saccharomyces cerevisiae. Given its ability to complement the susceptibility phenotype of its S. cerevisiae homolog, ScAqr1, CgAqr1 was proposed to play a similar role in mediating the extrusion of chemical compounds. Significantly, the expression of this gene was found to reduce the intracellular accumulation of (3)H-flucytosine and, to a moderate extent, of (3)H-clotrimazole, consistent with a direct role in antifungal drug efflux. Interestingly, no effect of CgAQR1 deletion could be found on the intracellular accumulation of (14)C-acetic acid, suggesting that its role in acetic acid resistance may be indirect, presumably through the transport of a still unidentified physiological substrate. Although neither of the tested chemicals induces changes in CgAQR1 expression, pre-exposure to flucytosine or clotrimazole was found to make C. glabrata cells more sensitive to acetic acid stress. Results from this study show that CgAqr1 is an antifungal drug resistance determinant and raise the hypothesis that it may play a role in C. glabrata persistent colonization

  16. The dual role of Candida glabrata Drug:H+ Antiporter CgAqr1 (ORF CAGL0J09944g in antifungal drug and acetic acid resistance

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    Catarina eCosta

    2013-06-01

    Full Text Available Opportunistic Candida species often have to cope with inhibitory concentrations of acetic acid, in the acidic environment of the vaginal mucosa. Given that the ability of these yeast species to tolerate stress induced by weak acids and antifungal drugs appears to be a key factor in their persistence and virulence, it is crucial to understand the underlying mechanisms.In this study, the Drug:H+ Antiporter CgAqr1 (ORF CAGL0J09944g, from Candida glabrata, was identified as a determinant of resistance to acetic acid, and also to the antifungal agents flucytosine and, less significantly, clotrimazole. These antifungals were found to act synergistically with acetic acid against this pathogen. The action of CgAqr1 in this phenomenon was analyzed. Using a GFP fusion, CgAqr1 was found to localize to the plasma membrane and to membrane vesicles when expressed in C. glabrata or, heterologously, in Saccharomyces cerevisiae. Given its ability to complement the susceptibility phenotype of its S. cerevisiae homolog, ScAqr1, CgAqr1 was proposed to play a similar role in mediating the extrusion of chemical compounds. Significantly, the expression of this gene was found to reduce the intracellular accumulation of 3H-flucytosine and, to a moderate extent, of 3H-clotrimazole, consistent with a direct role in antifungal drug efflux. Interestingly, no effect of CgAQR1 deletion could be found on the intracellular accumulation of 14C-acetic acid, suggesting that its role in acetic acid resistance may be indirect, presumably through the transport of a still unidentified physiological substrate. Although neither of the tested chemicals induces changes in CgAQR1 expression, pre-exposure to flucytosine or clotrimazole was found to make C. glabrata cells more sensitive to acetic acid stress. Results from this study show that CgAqr1 is an antifungal drug resistance determinant and raise the hypothesis that it may play a role in C. glabrata persistent colonization and

  17. Antibacterial and antifungal activity of Terminalia arjuna Wight & Arn. bark against multi-drug resistant clinical isolates

    Institute of Scientific and Technical Information of China (English)

    Sukalyani Debnath; Diganta Dey; Sudipta Hazra; Subhalakshmi Ghosh; Ratnamala Ray; Banasri Hazra

    2013-01-01

    Objective: To evaluate antimicrobial activity of Terminalia arjuna (T. arjuna) bark against clinical strains of multi-drug resistant bacteria, and Candida spp. isolated from patients, as well as the corresponding reference strains.Methods:were evaluated by agar-well diffusion method, followed by determination of minimum inhibitory concentration (MIC) by broth micro-dilution method. The clinical isolates were studied for antibacterial susceptibility by Kirby and Bauer disk diffusion technique. The antimicrobial activity of water, methanol and chloroform extracts of T. arjuna bark Results: The water and methanolic extracts of T. arjuna bark produced significant zones of inhibition against twenty-two tested bacteria including eight uropathogens. MIC values against the bacteria were found in the range of 0.16 to 2.56 mg/mL. The chloroform extract did not exhibit antibacterial activity. The polar extracts of T. arjuna also demonstrated strong antifungal effect against eight species of Candida, with MIC between 0.16 and 0.64 mg/mL. The antimicrobial efficacy of the polar extracts was found to be commensurate with high polyphenol content in contrast to the non-polar (chloroform fraction). Conclusions: This study has revealed the therapeutic prospect of T. arjuna bark for the treatment of microbial diseases. The polar fraction of the bark could be used for development of novel antimicrobial agents, particularly against urinary tract infections, and candidiasis/candidaemia.

  18. Therapeutic drug monitoring (TDM) of antifungal agents: guidelines from the British Society for Medical Mycology

    OpenAIRE

    Ashbee, H. Ruth; Barnes, Rosemary A.; Johnson, Elizabeth M.; Richardson, Malcolm D.; Gorton, Rebecca; Hope, William W.

    2013-01-01

    The burden of human disease related to medically important fungal pathogens is substantial. An improved understanding of antifungal pharmacology and antifungal pharmacokinetics–pharmacodynamics has resulted in therapeutic drug monitoring (TDM) becoming a valuable adjunct to the routine administration of some antifungal agents. TDM may increase the probability of a successful outcome, prevent drug-related toxicity and potentially prevent the emergence of antifungal drug resistance. Much of the...

  19. Drug Resistance

    Science.gov (United States)

    HIV Treatment Drug Resistance (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points As HIV multiplies in the ... the risk of drug resistance. What is HIV drug resistance? Once a person becomes infected with HIV, ...

  20. 21 CFR 333.250 - Labeling of antifungal drug products.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Labeling of antifungal drug products. 333.250... Antifungal Drug Products § 333.250 Labeling of antifungal drug products. (a) Statement of identity. The... “antifungal.” (b) Indications. The labeling of the product states, under the heading “Indications,” the...

  1. Resistance to antifungals that target CYP51.

    Science.gov (United States)

    Parker, Josie E; Warrilow, Andrew G S; Price, Claire L; Mullins, Jonathan G L; Kelly, Diane E; Kelly, Steven L

    2014-10-01

    Fungal diseases are an increasing global burden. Fungi are now recognised to kill more people annually than malaria, whilst in agriculture, fungi threaten crop yields and food security. Azole resistance, mediated by several mechanisms including point mutations in the target enzyme (CYP51), is increasing through selection pressure as a result of widespread use of triazole fungicides in agriculture and triazole antifungal drugs in the clinic. Mutations similar to those seen in clinical isolates as long ago as the 1990s in Candida albicans and later in Aspergillus fumigatus have been identified in agriculturally important fungal species and also wider combinations of point mutations. Recently, evidence that mutations originate in the field and now appear in clinical infections has been suggested. This situation is likely to increase in prevalence as triazole fungicide use continues to rise. Here, we review the progress made in understanding azole resistance found amongst clinically and agriculturally important fungal species focussing on resistance mechanisms associated with CYP51. Biochemical characterisation of wild-type and mutant CYP51 enzymes through ligand binding studies and azole IC50 determinations is an important tool for understanding azole susceptibility and can be used in conjunction with microbiological methods (MIC50 values), molecular biological studies (site-directed mutagenesis) and protein modelling studies to inform future antifungal development with increased specificity for the target enzyme over the host homologue. PMID:25320648

  2. Hrk1 plays both Hog1-dependent and -independent roles in controlling stress response and antifungal drug resistance in Cryptococcus neoformans.

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    Seo-Young Kim

    Full Text Available The HOG (High Osmolarity Glycerol response pathway plays a central role in controlling stress response, ergosterol biosynthesis, virulence factor production, and differentiation of Cryptococcus neoformans, which causes fatal fungal meningoencephalitis. Recent transcriptome analysis of the HOG pathway discovered a Hog1-regulated gene (CNAG_00130.2, encoding a putative protein kinase orthologous to Rck1/2 in Saccharomyces cerevisiae and Srk1 in Schizosaccharomyces pombe. Its function is not known in C. neoformans. The present study functionally characterized the role of Hrk1 in C. neoformans. Northern blot analysis confirmed that HRK1 expression depends on the Hog1 MAPK. Similar to the hog1Δ mutant, the hrk1Δ mutant exhibited almost complete resistance to fludioxonil, which triggers glycerol biosynthesis via the HOG pathway. Supporting this, the hrk1Δ mutant showed reduced intracellular glycerol accumulation and swollen cell morphology in response to fludioxonil, further suggesting that Hrk1 works downstream of the HOG pathway. However, Hrk1 also appeared to have Hog1-independent functions. Mutation of HRK1 not only further increased osmosensitivity of the hog1Δ mutant, but also suppressed increased azole-resistance of the hog1Δ mutant in an Erg11-independent manner. Furthermore, unlike the hog1Δ mutant, Hrk1 was not involved in capsule biosynthesis. Hrk1 was slightly involved in melanin production but dispensable for virulence of C. neoformans. These findings suggest that Hrk1 plays both Hog1-dependent and -independent roles in stress and antifungal drug susceptibility and virulence factor production in C. neoformans. Particularly, the finding that inhibition of Hrk1 substantially increases azole drug susceptibility provides a novel strategy for combination antifungal therapy.

  3. Echinocandins: A ray of hope in antifungal drug therapy

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    Grover Neeta

    2010-01-01

    Full Text Available Invasive fungal infections are on the rise. Amphotericin B and azole antifungals have been the mainstay of antifungal therapy so far. The high incidence of infusion related toxicity and nephrotoxicity with amphotericin B and the emergence of fluconazole resistant strains of Candida glabrata egged on the search for alternatives. Echinocandins are a new class of antifungal drugs that act by inhibition of β (1, 3-D- glucan synthase, a key enzyme necessary for integrity of the fungal cell wall. Caspofungin was the first drug in this class to be approved. It is indicated for esophageal candidiasis, candidemia, invasive candidiasis, empirical therapy in febrile neutropenia and invasive aspergillosis. Response rates are comparable to those of amphotericin B and fluconazole. Micafungin is presently approved for esophageal candidiasis, for prophylaxis of candida infections in patients undergoing hematopoietic stem cell transplant (HSCT and in disseminated candidiasis and candidemia. The currently approved indications for anidulafungin are esophageal candidiasis, candidemia and invasive candidiasis. The incidence of infusion related adverse effects and nephrotoxicity is much lower than with amphotericin B. The main adverse effect is hepatotoxicity and derangement of serum transaminases. Liver function may need to be monitored. They are, however, safer in renal impairment. Even though a better pharmacoeconomical choice than amphotericin B, the higher cost of these drugs in comparison to azole antifungals is likely to limit their use to azole resistant cases of candidial infections and as salvage therapy in invasive aspergillosis rather than as first line drugs.

  4. Mystery unraveled about antifungal drug targets

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ A long-standing mystery about the functional roles of the N-terminal region of protein N-myristoyltransferase, an ideal target for antifungal drugs, was recently decoded, thanks to the threeyear joint efforts of researchers from the CAS Key Laboratory of Molecular Biology and their US colleagues at the DuPont Stine Haskell Research Center.

  5. Antifungal effect of cumin essential oil alone and in combination with antifungal drugs

    OpenAIRE

    SAHADEO PATIL; PANKAJ MAKNIKAR; SUSHILKUMAR WANKHADE; CHANDRAKIRAN UKESH; MAHENDRA RA

    2015-01-01

    Abstract. Patil S, Maknikar P, Wankhade S, Ukesh C, Rai M. 2015. Antifungal effect of cumin essential oil alone and in combination with antifungal drugs. Nusantara Bioscience 7: 55-59. We report evaluation of antifungal activity of cumin seed oil and its pharmacological interactions when used in combination with some of the widely used conventional antifungal drugs using CLSI broth microdilution, agar disc diffusion and checkerboard microtitre assay against Candida. The essential oil was obta...

  6. Oral Antifungal Drugs in the Treatment of Dermatomycosis.

    Science.gov (United States)

    Tsunemi, Yuichiro

    2016-01-01

    Oral antifungal drugs are used primarily to treat tinea unguium; however, they are also useful for other types of tinea. For example, a combination of topical and oral antifungal drugs is effective in hyperkeratotic tinea pedis that is unresponsive to topical monotherapy. In cases of tinea facialis adjacent to the eyes, ears, or mouth, or widespread tinea corporis, or tinea cruris involving the complex skin folds of the external genitalia, it is difficult to apply topical drugs to all the lesions; therefore, oral antifungal drugs are necessary. Oral antifungal drugs are also useful not only for tinea but for widespread pityriasis versicolor and Malassezia folliculitis, candidal onychomycosis, and candidal paronychia and onychia. Topical antifungal drugs are in fact unsuitable for some mycoses. In tinea capitis, for example, irritation by topical drugs is likely to enhance inflammation; therefore, oral antifungal drug monotherapy is preferable. In interdigital tinea pedis with erosion or contact dermatitis, topical drugs are difficult to use because they tend to cause irritant dermatitis, resulting in exacerbation of the condition. In such cases, treatment should begin with a combination of topical corticosteroid therapy and oral antifungal drugs active against dermatophytes. Topical antifungal drugs are used after the complications resolve. A combination of topical and oral antifungal drugs can shorten the treatment period, thus improving patient adherence to topical treatment. Oral antifungal drugs are useful because of their wide range of applications in the treatment of dermatomycosis. PMID:27251319

  7. Tolerability and safety of antifungal drugs

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    Francesco Scaglione

    2013-08-01

    Full Text Available When treating critically ill patients, as those with fungal infections, attention should be focused on the appropriate use of drugs, especially in terms of dose, safety, and tolerability. The fungal infection itself and the concomitant physiological disorders concur to increase the risk of mortality in these patients, therefore the use of any antifungal agent should be carefully evaluated, considering both the direct action on the target fungus and the adverse effects eventually caused. Among antifungal drugs, echinocandins have the greatest tolerability. In fact, unlike amphotericin B, showing nephrotoxicity, and azoles, which are hepatotoxic, the use of echinocandins doesn’t result in major adverse events.http://dx.doi.org/10.7175/rhc.v4i2s.873

  8. Antifungal effect of cumin essential oil alone and in combination with antifungal drugs

    Directory of Open Access Journals (Sweden)

    SAHADEO PATIL

    2015-05-01

    Full Text Available Abstract. Patil S, Maknikar P, Wankhade S, Ukesh C, Rai M. 2015. Antifungal effect of cumin essential oil alone and in combination with antifungal drugs. Nusantara Bioscience 7: 55-59. We report evaluation of antifungal activity of cumin seed oil and its pharmacological interactions when used in combination with some of the widely used conventional antifungal drugs using CLSI broth microdilution, agar disc diffusion and checkerboard microtitre assay against Candida. The essential oil was obtained from cumin seeds using hydrodistillation technique and was later evaluated for the presence of major chemical constituents present in it using gas chromatography and mass spectrometry (GC-MS assay. The GC-MS assay revealed the abundance of γ-terpinene (35.42% followed by p-cymene (30.72%. The agar disc diffusion assay demonstrated highly potent antifungal effect against Candida species. Moreover, the combination of cumin essential oil (CEO with conventional antifungal drugs was found to reduce the individual MIC of antifungal drug suggesting the occurrence of synergistic interactions. Therefore, the therapy involving combinations of CEO and conventional antifungal drugs can be used for reducing the toxicity induced by antifungal drugs and at the same time enhancing their antifungal efficacy in controlling the infections caused due to Candida species.

  9. SUSCEPTIBILITY OF CANDIDA SPECIES TO ANTIFUNGAL DRUGS IN WESTERN INDIA

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    Geeta M Vaghela

    2015-06-01

    Full Text Available Introduction: The increase in candidaemia is associated with high mortality. A shift has been observed in the relative frequency of each Candida spp. isolated from blood. Options of the antifungal drugs available for treatment of systemic and invasive candidiasis are restricted to polyenes, allylamines, azoles and recently developed echinocandin class of molecules. A rise in the incidence of antifungal resistance to Candida spp. has also been reported over the past decade. Studies on prevalence of infections and antifungal susceptibility testing are useful in deciding clinical strategies. Aims: To do species level identification and detect resistance, if any, among Indian clinical isolates of C. albicans. Methodology: From total 135 patients from a tertiary care hospital of Gujarat, Candida species were isolated from different clinical specimens. The growth of Candida on Sabouraud's dextrose agar was confirmed by Gram staining in which gram positive budding fungal cells were observed. Then its growth was examined for colony morphology on Sabouraud's dextrose agar and chlamydospore production on Corn meal tween 80 agar. Germ tube tests and other biochemical tests like sugar fermentation, sugar assimilation and urease test were performed to identify the species of Candida. Antifungal susceptibility testing was performed by NCCLS M44-A Disc diffusion method. Results: Out of total 135 samples, C. Albicans were isolated from 52 (38.5%. Among Non Albican Candid (NAC, Candida glabrata was 36 (26.7% followed by Candida tropicalis 25(18.5%. C. albicans was found resistant to Fluconazole, Itraconazole and Amphotericine B in 3.8%, 3.8% and 1.9% cases respectively. For NAC, resistance of Fluconazole, Itraconazole and Amphotericine B was found in 4.8%, 3.6% and 2.4% cases respectively. [Natl J Med Res 2015; 5(2.000: 122-126

  10. Multidrug-Resistant Transporter Mdr1p-Mediated Uptake of a Novel Antifungal Compound

    OpenAIRE

    Sun, Nuo; Li, Dongmei; Fonzi, William; Xin LI; Zhang, Lixin; Calderone, Richard

    2013-01-01

    The activity of many anti-infectious drugs has been compromised by the evolution of multidrug-resistant (MDR) pathogens. For life-threatening fungal infections, such as those caused by Candida albicans, overexpression of MDR1, which encodes an MDR efflux pump of the major facilitator superfamily (MFS), often confers resistance to chemically unrelated substances, including the most commonly used azole antifungals. As the development of new and efficacious antifungals has lagged far behind the ...

  11. Impact of New Antifungal Breakpoints on Antifungal Resistance in Candida Species

    OpenAIRE

    Fothergill, Annette W.; Sutton, Deanna A.; McCarthy, Dora I.; Wiederhold, Nathan P.

    2014-01-01

    We reviewed our antifungal susceptibility data for micafungin, anidulafungin, fluconazole, and voriconazole against Candida species and compared resistance rates determined by the previous and recently revised CLSI antifungal breakpoints. With the new breakpoints, resistance was significantly increased for micafungin (from 0.8% to 7.6%), anidulafungin (from 0.9% to 7.3%), and voriconazole (from 6.1% to 18.4%) against Candida glabrata. Resistance was also increased for fluconazole against Cand...

  12. Use of antifungal drugs in hematology

    Directory of Open Access Journals (Sweden)

    Marcio Nucci

    2012-01-01

    Full Text Available Invasive fungal disease represents a major complication in hematological patients. Antifungal agents are frequently used in hematologic patients for different purposes. In neutropenic patients, antifungal agents may be used as prophylaxis, as empiric or preemptive therapy, or to treat an invasive fungal disease that has been diagnosed. The hematologist must be familiar with the epidemiology, diagnostic tools and strategies of antifungal use, as well as the pharmacologic proprieties of the different antifungal agents. In this paper the principal antifungal agents used in hematologic patients will be discussed as will the clinical scenarios where these agents have been used.

  13. A Genomewide Screen in Schizosaccharomyces pombe for Genes Affecting the Sensitivity of Antifungal Drugs That Target Ergosterol Biosynthesis

    OpenAIRE

    Fang, Yue; Hu, Lingling; Zhou, Xin; Jaiseng, Wurentuya; Zhang, Ben; Takami, Tomonori; Kuno, Takayoshi

    2012-01-01

    We performed a genomewide screen for altered sensitivity to antifungal drugs, including clotrimazole and terbinafine, that target ergosterol biosynthesis using a Schizosaccharomyces pombe gene deletion library consisting of 3,004 nonessential haploid deletion mutants. We identified 109 mutants that were hypersensitive and 11 mutants that were resistant to these antifungals. Proteins whose absence rendered cells sensitive to these antifungals were classified into various functional categories,...

  14. Use of antifungal drugs in hematology

    OpenAIRE

    Marcio Nucci

    2012-01-01

    Invasive fungal disease represents a major complication in hematological patients. Antifungal agents are frequently used in hematologic patients for different purposes. In neutropenic patients, antifungal agents may be used as prophylaxis, as empiric or preemptive therapy, or to treat an invasive fungal disease that has been diagnosed. The hematologist must be familiar with the epidemiology, diagnostic tools and strategies of antifungal use, as well as the pharmacologic proprieties of the dif...

  15. Survey on drug resistance of Candida to common antifungal drugs%念珠菌对临床常用抗真菌药物的耐药性分析

    Institute of Scientific and Technical Information of China (English)

    张丽君; 王博

    2012-01-01

    Objective To study the drug resistance of Candida to commonly used antifungal drugs and to survey the distribution of Candida infection in this area. Methods By using Candida color culture medium for cultivation and identification of Candida, and K - B method was used for drug sensitivity testing. Results The specimens from respiratory tract of 267 cases of Candida infection accounted for 70. 8% , urine specimens accounted for 16.9% , pus specimens for 6. 4% , pleural effusion and ascites for 3. 4% , cerebrospinal fluid for 0.7% and blood samples for 1.9%. Among species distribution, Candida albicans accounted for 61. 4% , Candida tropicalis accounted for 10. 9% , Candida krusei accounted for 6.4%, Candida glabrata accounted for 8. 6% , and other species of Candida accounted for 12.7% . The rate of resistance was 1. 1 % to ampho-tericinB, 13.1% to 5 - fluorocytosine, 46. 4% to itraconazole, 48. 3% to fluconazole and 34. 8% to ketoconazole. Conclusion The incidence of infection with Candida is in rising tendency, distribution of species and manifestations in drug resistance are different, hence clinical medication should be based on drug sensitivity test for rational application of antifungal drugs.%目的 研究本地区念珠菌感染构成及对临床常用抗真菌药物的耐药情况.方法 使用念珠菌显色培养基对念珠菌进行培养鉴定,并用现行纸片扩散法(K-B法)进行药敏实验.结果 267例念珠菌感染中呼吸道标本占70.8%、尿液占16.9%,脓液6.4%,胸腹水3.4%,脑脊液0.7%,血液1.9%;菌种分布分别为白色念珠菌占61.4%,热带念珠菌占10.9%,克柔念珠菌占6.4%,光滑念珠菌占8.6%,其他念珠菌占12.7%;耐药情况分别为两性霉素B耐药性1.1%,5-氟胞嘧啶13.1%,依曲康唑46.4%,氟康唑48.3%,酮康唑34.8%.结论 念珠菌的感染呈上升态势,菌种分布及耐药性表现均不同,临床上应根据药敏实验合理使用抗真菌药物.

  16. Enhanced activity of antifungal drugs using natural phenolics against yeast strains of Candida and Cryptococcus

    Science.gov (United States)

    Candidiasis and cryptococcosis are diseases of widening global incidence as a result of increasing immunosuppressive disorders, such as AIDS. An enduring problem for treatment of these mycoses is recurrent development of resistance to introduced antifungal drugs. We examined the potential for enhan...

  17. Candida Infections: An Update on Host Immune Defenses and Anti-Fungal Drugs

    Directory of Open Access Journals (Sweden)

    Ning Gao

    2016-04-01

    Full Text Available Infections by fungal pathogens such as Candida albicans and non-albicans Candida species are becoming increasing prevalent in the human population. Such pathogens cause life-threatening diseases with high mortality, particularly in immunocompromised patients. Host defenses against fungal infections are provided by an exquisite interplay between innate and adaptive immune responses. However, effective anti-fungal agents for Candida infections are limited, and fungal drug resistance is a significant treatment challenge. In this review, we summarize the current understanding of host–fungal interactions, discuss the modes action of anti-fungal drugs, explore host defense mechanisms, and define the new challenges for treating Candida infections.

  18. Antifungal drug discovery through the study of invertebrate model hosts

    OpenAIRE

    Pukkila-Worley, R.; Holson, E.; Wagner, F.; Mylonakis, E.

    2009-01-01

    There is an urgent need for new antifungal agents that are both effective and non-toxic in the therapy of systemic mycoses. The model nematode Caenorhabditis elegans has been used both to elucidate evolutionarily conserved components of host-pathogen interactions and to screen large chemical libraries for novel antimicrobial compounds. Here we review the use of C. elegans models in drug discovery and discuss caffeic acid phenethyl ester, a novel antifungal agent identified using an in vivo sc...

  19. Solid lipid nanoparticles for antifungal drugs delivery for topical applications.

    Science.gov (United States)

    Trombino, Sonia; Mellace, Silvia; Cassano, Roberta

    2016-09-01

    Systemic and local infections caused by fungi, in particular those concerning the skin and nails, are increasing. Various drugs are used for mycoses treatment such as amphotericin B, nystatin and ketoconazole, fluconazole, itraconazole and fluconazole, among others. Unfortunately, many of these antifungal agents can cause side effects such as allergic and severe skin reaction. With the aim to reduce these side effects and maximize the antifungal drug activity, various drug-delivery systems have been formulated and been investigated in the last few years. In this context, solid lipid nanoparticles are attracting great attention. The aim of this review is to highlight the role of solid lipid nanoparticles as carriers of antifungal drugs for topical applications. PMID:27582235

  20. Synergy and antagonism between iron chelators and antifungal drugs in Cryptococcus.

    Science.gov (United States)

    Lai, Yu-Wen; Campbell, Leona T; Wilkins, Marc R; Pang, Chi Nam Ignatius; Chen, Sharon; Carter, Dee A

    2016-10-01

    Fungal infections remain very difficult to treat, and developing new antifungal drugs is difficult and expensive. Recent approaches therefore seek to augment existing antifungals with synergistic agents that can lower the therapeutic dose, increase efficacy and prevent resistance from developing. Iron limitation can inhibit microbial growth, and iron chelators have been employed to treat fungal infections. In this study, chequerboard testing was used to explore combinations of iron chelators with antifungal agents against pathogenic Cryptococcus spp. with the aim of determining how disruption to iron homeostasis affects antifungal susceptibility. The iron chelators ethylenediaminetetraacetic acid (EDTA), deferoxamine (DFO), deferiprone (DFP), deferasirox (DSX), ciclopirox olamine and lactoferrin (LF) were paired with the antifungal agents amphotericin B (AmB), fluconazole, itraconazole, voriconazole and caspofungin. All chelators except for DFO increased the efficacy of AmB, and significant synergy was seen between AmB and LF for all Cryptococcus strains. Addition of exogenous iron rescued cells from the antifungal effect of LF alone but could not prevent inhibition by AmB + LF, indicating that synergy was not due primarily to iron chelation but to other properties of LF that were potentiated in the presence of AmB. Significant synergy was not seen consistently for other antifungal-chelator combinations, and EDTA, DSX and DFP antagonised the activity of azole drugs in strains of Cryptococcus neoformans var. grubii. This study highlights the range of interactions that can be induced by chelators and indicates that most antifungal drugs are not enhanced by iron limitation in Cryptococcus. PMID:27474467

  1. Candida Infections, Causes, Targets, and Resistance Mechanisms: Traditional and Alternative Antifungal Agents

    Directory of Open Access Journals (Sweden)

    Claudia Spampinato

    2013-01-01

    Full Text Available The genus Candida includes about 200 different species, but only a few species are human opportunistic pathogens and cause infections when the host becomes debilitated or immunocompromised. Candida infections can be superficial or invasive. Superficial infections often affect the skin or mucous membranes and can be treated successfully with topical antifungal drugs. However, invasive fungal infections are often life-threatening, probably due to inefficient diagnostic methods and inappropriate initial antifungal therapies. Here, we briefly review our current knowledge of pathogenic species of the genus Candida and yeast infection causes and then focus on current antifungal drugs and resistance mechanisms. An overview of new therapeutic alternatives for the treatment of Candida infections is also provided.

  2. Mode of Antifungal Drugs Interaction with Cytochrome P- 450

    Directory of Open Access Journals (Sweden)

    M- Mahmodian

    1991-07-01

    Full Text Available Computer was used to identify the interactions of substrates and antifungal drugs with the enzyme, Cytochrome P-450; and then Molplot.bas computer program was applied to get three dimensional figures of 5-hydroxy camphor.oxidation products of camphor analogues, and antifungal drugs.Cartesian characteristics of atoms building molecules, are taken from Buildz. for program, which can calculate X,Y,Z coordinates of atoms by Zmatrix data. The other program which can calculate X,Y,Z coordinates, using fractional characteristics, is the Coord, for program that, gives our cartesian characteristics of the atoms of molecule, then by using these data, we obtain three dimensional figures and distance between active atoms in compounds under consideration. Results show that distance between two oxygen atoms in 5-exo-hydroxy- camphor and the other compounds obtained from oxidation of camphor analogues, with the distance of two oxygen atoms in antifungal compounds under discussion are equal. Therefore, we can conclude that, the antifungal molecule also interacts with enzyme's active site, by its own sites, in a similar manner to the 5-hydroxy camphor molecule, which is:"n1. Nitrogen atom (N of Imidazole and Triazole ring in antifungal molecule with Iron atom in heam molecule belonging to Cytochrome P-450 enzyme, are coordinated."n2. The other atoms such as : 0,S or N in structure of the antifungal drug are coordinated with hydrogen atom of hydroxyl group belong ing to Tyr-96 in the structure of enzyme, forming hydrogen bonding.

  3. Sensitization of Candida albicans biofilms to various antifungal drugs by cyclosporine A

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    Shinde Ravikumar B

    2012-10-01

    Full Text Available Abstract Background Biofilms formed by Candida albicans are resistant towards most of the available antifungal drugs. Therefore, infections associated with Candida biofilms are considered as a threat to immunocompromised patients. Combinatorial drug therapy may be a good strategy to combat C. albicans biofilms. Methods Combinations of five antifungal drugs- fluconazole (FLC, voriconazole (VOR, caspofungin (CSP, amphotericin B (AmB and nystatin (NYT with cyclosporine A (CSA were tested in vitro against planktonic and biofilm growth of C. albicans. Standard broth micro dilution method was used to study planktonic growth, while biofilms were studied in an in vitro biofilm model. A chequerboard format was used to determine fractional inhibitory concentration indices (FICI of combination effects. Biofilm growth was analyzed using XTT-metabolic assay. Results MICs of various antifungal drugs for planktonic growth of C. albicans were lowered in combination with CSA by 2 to 16 fold. Activity against biofilm development with FIC indices of 0.26, 0.28, 0.31 and 0.25 indicated synergistic interactions between FLC-CSA, VOR-CSA, CSP-CSA and AmB-CSA, respectively. Increase in efficacy of the drugs FLC, VOR and CSP against mature biofilms after addition of 62.5 μg/ml of CSA was evident with FIC indices 0.06, 0.14 and 0.37, respectively. Conclusions The combinations with CSA resulted in increased susceptibility of biofilms to antifungal drugs. Combination of antifungal drugs with CSA would be an effective prophylactic and therapeutic strategy against biofilm associated C. albicans infections.

  4. Resistance of Candida albicans biofilms to antifungal agents in vitro.

    OpenAIRE

    Hawser, S. P.; Douglas, L J

    1995-01-01

    Biofilms formed by Candida albicans on small discs of catheter material were resistant to the action of five clinically important antifungal agents as determined by [3H]leucine incorporation and tetrazolium reduction assays. Fluconazole showed the greatest activity, and amphotericin B showed the least activity against biofilm cells. These findings were confirmed by scanning electron microscopy of the biofilms.

  5. Caenorhabditis elegans-based Model Systems for Antifungal Drug Discovery

    OpenAIRE

    Cleo G Anastassopoulou; Fuchs, Beth Burgwyn; Mylonakis, Eleftherios

    2011-01-01

    The substantial morbidity and mortality associated with invasive fungal infections constitute undisputed tokens of their severity. The continued expansion of susceptible population groups (such as immunocompromised individuals, patients undergoing extensive surgery, and those hospitalized with serious underlying diseases especially in the intensive care unit) and the limitations of current antifungal agents due to toxicity issues or to the development of resistance, mandate the development of...

  6. Calcium signaling mediates antifungal activity of triazole drugs in the Aspergilli.

    Science.gov (United States)

    Liu, Fei-fei; Pu, Li; Zheng, Qing-qing; Zhang, Yuan-wei; Gao, Rong-sui; Xu, Xu-shi; Zhang, Shi-zhu; Lu, Ling

    2015-08-01

    Azoles are widely applied and largely effective as antifungals; however, the increasing prevalence of clinically resistant isolates has yet to be matched by approaches to improve the efficacy of antimicrobial therapy. In this study, using the model fungus Aspergillus nidulans and one of the most common human pathogen Aspergillus fumigatus as research materials, we present the evidence that calcium signaling is involved in the azole-antifungals-induced stress-response reactions. In normal media, antifungal-itraconazole (ITZ) is able to induce the [Ca(2+)]c increased sharply but the addition of calcium chelator-EGTA or BAPTA almost blocks the calcium influx responses, resulted in the dramatically decreasing of [Ca(2+)]c transient. Real-time PCR analysis verified that six-tested Ca(2+)-inducible genes-two calcium channels (cchA/midA), a calmodulin-dependent phosphatase-calcineurin (cnaA), a transcription factor-crzA, and two calcium transporters (pmrA/pmcA)-could be transiently up-regulated by adding ITZ, indicating these components are involved in the azole stress-response reaction. Defect of cnaA or crzA caused more susceptibility to azole antifungals than did single mutants or double deletions of midA and cchA. Notably, EGTA may influence Rh123 accumulation as an azole-mimicking substrate through the process of the drug absorption. In vivo studies of a Galleria mellonella model identified that the calcium chelator works as an adjunct antifungal agent with azoles for invasive aspergillosis. Most importantly, combination of ITZ and EGTA or ITZ with calcium signaling inhibitor-FK506 greatly enhances the ITZ efficacy. Thus, our study provides potential clues that specific inhibitors of calcium signaling could be clinically useful adjuncts to conventional azole antifungals in the Aspergilli.

  7. Antifungal activity of ibuprofen against aspergillus species and its interaction with common antifungal drugs

    Institute of Scientific and Technical Information of China (English)

    LI Li-juan; CHEN Wei; XU Hui; WAN Zhe; LI Ruo-yu; LIU Wei

    2010-01-01

    Background The incidence of invasive aspergillosis (IA) has increased in frequency in immunocompromised patients with a variety of diseases. The poor prognosis might be due to limited treatment option. This study aimed to evaluate antifungal activity of ibuprofen against clinical isolates of aspergillus species, as well as its interaction with azoles or with amphotericin B or with micafungin.Methods Antifungal activity of ibuprofen against 10 strains of Aspergillus fumigatus, Aspergillus flavus, and Aspergillus terreus were tested with both disk diffusion assay and standard broth microdilution method. To determine whether ibuprofen combined with itraconazole, voriconazole, amphotericin B, or micafungin had interactive effects on aspergillus spp., we used both disk diffusion assay and Chequerboard method.Results As for disk diffusion method, ibuprofen produced a zone of growth inhibition with diameters of (20.1±3.9) mm at 48 hours of incubation. As for broth microdilution method, the minimal inhibitory concentration (MIC) ranges of ibuprofen against aspergillus spp. were 1000-2000 μg/ml, and the minimal fungicidal concentration (MFC) ranges of that was 2000-8000 μg/ml. For 2 of 5 isolates, when ibuprofen combined with itraconazole or voriconazole, the zones of growth inhibition were larger than those of the individual drug. The results of Chequerboard method showed that fractional inhibitory concentration index (FICI) ranges were 1.125-2.500.Conclusions Ibuprofen is active against aspergillus spp.. And ibuprofen does not affect the in vitro activity of itraconazole, voriconazole, amphotericin B or micafungin against aspergillus spp..

  8. Substitutions at Methionine 220 in the 14α-Sterol Demethylase (Cyp51A) of Aspergillus fumigatus Are Responsible for Resistance In Vitro to Azole Antifungal Drugs

    OpenAIRE

    Mellado, E.; Garcia-Effron, G.; Alcazar-Fuoli, L.; Cuenca-Estrella, M.; Rodriguez-Tudela, J. L.

    2004-01-01

    Five clinical isolates of Aspergillus fumigatus that exhibited similar patterns of reduced susceptibility to itraconazole and other triazole drugs were analyzed. Sequence analysis of genes (cyp51A and cyp51B) encoding the 14α-sterol demethylases revealed that all five strains harbored mutations in cyp51A resulting in the replacement of methionine at residue 220 by valine, lysine, or threonine. When the mutated cyp51A genes were introduced into an A. fumigatus wild-type strain, the transforman...

  9. Mycotoxins and Antifungal Drug Interactions: Implications in the Treatment of Illnesses Due to Indoor Chronic Toxigenic Mold Exposures

    Directory of Open Access Journals (Sweden)

    Ebere C. Anyanwu

    2004-01-01

    Full Text Available Chronic exposure to toxigenic molds in water-damaged buildings is an indoor environmental health problem to which escalating health and property insurance costs are raising a statewide concern in recent times. This paper reviews the structural and functional properties of mycotoxins produced by toxigenic molds and their interactive health implications with antifungal drugs. Fundamental bases of pathophysiological, neurodevelopmental, and cellular mechanisms of mycotoxic effects are evaluated. It is most likely that the interactions of mycotoxins with antifungal drugs may, at least in part, contribute to the observable persistent illnesses, antifungal drug resistance, and allergic reactions in patients exposed to chronic toxigenic molds. Safe dose level of mycotoxin in humans is not clear. Hence, the safety regulations in place at the moment remain inconclusive, precautionary, and arbitrary. Since some of the antifungal drugs are derived from molds, and since they have structural and functional groups similar to those of mycotoxins, the knowledge of their interactions are important in enhancing preventive measures.

  10. Kinetically Controlled Drug Resistance

    DEFF Research Database (Denmark)

    Sun, Xin E.; Hansen, Bjarne Gram; Hedstrom, Lizbeth

    2011-01-01

    The filamentous fungus Penicillium brevicompactum produces the immunosuppressive drug mycophenolic acid (MPA), which is a potent inhibitor of eukaryotic IMP dehydrogenases (IMPDHs). IMPDH catalyzes the conversion of IMP to XMP via a covalent enzyme intermediate, E-XMP*; MPA inhibits by trapping E...... of resistance is not apparent. Here, we show that, unlike MPA-sensitive IMPDHs, formation of E-XMP* is rate-limiting for both PbIMPDH-A and PbIMPDH-B. Therefore, MPA resistance derives from the failure to accumulate the drug-sensitive intermediate....

  11. Environmental isolation, biochemical identification, and antifungal drug susceptibility of Cryptococcus species

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    Valter Luis Iost Teodoro

    2013-12-01

    Full Text Available Introduction The incidence of opportunistic fungal infections has increased in recent years and is considered an important public health problem. Among systemic and opportunistic mycoses, cryptococcosis is distinguished by its clinical importance due to the increased risk of infection in individuals infected by human immunodeficiency virus. Methods To determine the occurrence of pathogenic Cryptococcus in pigeon excrement in the City of Araraquara, samples were collected from nine environments, including state and municipal schools, abandoned buildings, parks, and a hospital. The isolates were identified using classical tests, and susceptibility testing for the antifungal drugs (fluconazole, itraconazole, voriconazole, and amphotericin B independently was also performed. After collection, the excrement samples were plated on Niger agar and incubated at room temperature. Results A total of 87 bird dropping samples were collected, and 66.6% were positive for the genus Cryptococcus. The following species were identified: Cryptococcus neoformans (17.2%, Cryptococcus gattii (5.2%, Cryptococcus ater (3.5%, Cryptococcus laurentti (1.7%, and Cryptococcus luteolus (1.7%. A total of 70.7% of the isolates were not identified to the species level and are referred to as Cryptococcus spp. throughout the manuscript. Conclusions Although none of the isolates demonstrated resistance to antifungal drugs, the identification of infested areas, the proper control of birds, and the disinfection of these environments are essential for the epidemiological control of cryptococcosis.

  12. Drug resistance in malaria

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    S C Parija

    2011-01-01

    Full Text Available Antimalarial chemotherapy is an important component of all malaria control programmes throughout the world. This is especially so in light of the fact that there are no antimalarial vaccines which are available for clinical use at present. Emergence and spread of malaria parasites which are resistant to many of the available antimalarials today is, therefore, a major cause for concern. Till date, resistance to all groups of antimalarials excluding artemisinin has been reported. In recent years, in vitro resistance to even artemisinin has been described. While resistance to antibacterial agents has come to prominence as a clinical problem in recent years, antiparasitic resistance in general and antimalarial resistance in particular has not received much attention, especially in the Indian scenario. The present review deals with commonly used antimalarial drugs and the mechanisms of resistance to them. Various methods of detecting antimalarial resistance and avoiding the same have also been dealt with. Newer parasite targets which can be used in developing newer antimalarial agents and antimalarials obtained from plants have also been mentioned.

  13. Relationship between antifungal resistance of fluconazole resistant Candida albicans and mutations in ERG11 gene

    Institute of Scientific and Technical Information of China (English)

    FENG Li-juan; WAN Zhe; WANG Xiao-hong; LI Ruo-yu; LIU Wei

    2010-01-01

    Background The cytochrome P450 lanosterol 14α-demethylase(Erg11p) encoded by ERG11 gene is the primary target for azole antifungals.Changes in azole affinity of this enzyme caused by amino acid substitutions have been reported as a mechanism of azole antifungal resistance. This study aimed to investigate the relationship between amino acid substitutions in Erg11p from fluconazole resistant Candida albicans (C.albicans)isolates and their cross-resistance to azoles.Methods Mutations in ERG11 gene were screened in 10 clinical isolates of fluconazole resistant C.albicans strains.DNA sequence of ERG11 was determined by PCR based DNA sequencing.Results In the 10 isolates,19 types of amino acid substitutions were found,of which 10 substitutions (F72S, F103L, F145I, F198L, G206D, G227D, N349S, F416S, F422L and T482A) have not been reported previously. Mutations in ERG11 gene were detected in 9 isolates of fluconazole resistant C. albicans, but were not detected in 1 isolate. Conclusions Although no definite correlation was found between the type of amino acid substitutions in Erg11p and the phenotype of cross-resistance to azoles, the substitutions F72S, F145I and G227D in our study may be highly associated with resistance to azoles because of their special location in Erg11p.

  14. Flow cytometry susceptibility testing for conventional antifungal drugs and Comparison with the NCCLS Broth Macrodilution Test

    Directory of Open Access Journals (Sweden)

    M.J. Najafzadeh

    2009-08-01

    Full Text Available Introduction: During the last decade, the incidence of fungal infection has been increased in many countries. Because of the advent of resistant to antifungal agents, determination of an efficient strategic plan for treatment of fungal disease is an important issue in clinical mycology. Many methods have been introduced and developed for determination of invitro susceptibility tests. During the recent years, flow cytometry has developed to solving the problem and many papers have documented the usefulness of this technique. Materials and methods: As the first step, the invitro susceptibility of standard PTCC (Persian Type of Culture Collection strain and some clinical isolates of Candida consisting of Candida albicans, C. dubliniensis, C. glabrata, C. kefyer and C. parapsilosis were evaluated by macrodilution broth method according to NCCLS (National Committee for Clinical Laboratory Standards guidelines and flow cytometry susceptibility test. Results:  The data indicated that macro dilution broth methods and flow cytometry have the same results in determination of MIC (Minimum Inhibitory Concentration for amphotericin B, clotrimazole, fluconazole, ketoconazole and miconazole in C. albicans PTCC 5027 as well as clinical Candida isolates, such as C.albicans, C.dubliniensis, C.glabrata C.kefyr, and C.parapsilosis. Discussion: Comparing the results obtained by macrodilution broth and flow cytometry methods revealed that flow cytometry was faster. It is suggested that flow cytometry susceptibility test can be used as a powerful tool for determination of MIC and administration of the best antifungal drug in treatment of patients with Candida infections.

  15. Aspergillus nidulans galactofuranose biosynthesis affects antifungal drug sensitivity.

    Science.gov (United States)

    Alam, Md Kausar; El-Ganiny, Amira M; Afroz, Sharmin; Sanders, David A R; Liu, Juxin; Kaminskyj, Susan G W

    2012-12-01

    The cell wall is essential for fungal survival in natural environments. Many fungal wall carbohydrates are absent from humans, so they are a promising source of antifungal drug targets. Galactofuranose (Galf) is a sugar that decorates certain carbohydrates and lipids. It comprises about 5% of the Aspergillus fumigatus cell wall, and may play a role in systemic aspergillosis. We are studying Aspergillus wall formation in the tractable model system, A. nidulans. Previously we showed single-gene deletions of three sequential A. nidulans Galf biosynthesis proteins each caused similar hyphal morphogenesis defects and 500-fold reduced colony growth and sporulation. Here, we generated ugeA, ugmA and ugtA strains controlled by the alcA(p) or niiA(p) regulatable promoters. For repression and expression, alcA(p)-regulated strains were grown on complete medium with glucose or threonine, whereas niiA(p)-regulated strains were grown on minimal medium with ammonium or nitrate. Expression was assessed by qPCR and colony phenotype. The alcA(p) and niiA(p) strains produced similar effects: colonies resembling wild type for gene expression, and resembling deletion strains for gene repression. Galf immunolocalization using the L10 monoclonal antibody showed that ugmA deletion and repression phenotypes correlated with loss of hyphal wall Galf. None of the gene manipulations affected itraconazole sensitivity, as expected. Deletion of any of ugmA, ugeA, ugtA, their repression by alcA(p) or niiA(p), OR, ugmA overexpression by alcA(p), increased sensitivity to Caspofungin. Strains with alcA(p)-mediated overexpression of ugeA and ugtA had lower caspofungin sensitivity. Galf appears to play an important role in A. nidulans growth and vigor.

  16. Cyanobacteria, Lyngbya aestuarii and Aphanothece bullosa as antifungal and antileishmanial drug resources

    Institute of Scientific and Technical Information of China (English)

    Maheep Kumar; Manoj Kumar Tripathi; Akanksha Srivastava; Jalaj Kumar Gour; Rakesh Kumar Singh; Ragini Tilak; Ravi Kumar Asthana

    2013-01-01

    To investigate two cyanobacteria isolated from different origins i.e. Lyngbya aestuarii(L. aestuarii) from brackish water and Aphanothece bullosa (A. bullosa) from fresh water paddy fields for antifungal and antileishmanila activity taking Candida albicans and Leishmaniadonovain as targets. Methods: Biomass of L. aestuarii and A. bullosa were harvested after 40 and 60 d respectively and lyophilized twice in methanol (100%) and redissolved in methanol (5%) for bioassay. Antifungal bioassay was done by agar well diffusion method while antileishmanial, by counting cell numbers and flageller motility observation of promastigotes and amastigotes fromL. donovani . Fluconazole and 5% methanol were used as control. Results: Both the cyanobacteria were found to be potent source of antifungal activity keeping fluconazole as positive control, however, methanolic crude extract (15 mg/mL) of A. bullosa was found more potent (larger inhibition zone) over that of methanolic crude extract of L. aestuarii. Similarly antileishmanial activity of crude extract (24.0 mg/mL) of A. bullosa was superior over that of methanolic crude extract of L. aestuarii (25.6 mg/mL). Conclusions: Antifungal and antileishmanial drugs are still limited in the market. Screening of microbes possessing antifungal and antileishmanial activity drug is of prime importance. Cyanobacteria are little explored in this context because most of the drugs in human therapy are derived from microorganisms, mainly bacterial, fungal and actinomycetes. Thus in the present study two cyanobacterial strains from different origins showed potent source of antifungal and antileishmanial biomolecules.

  17. Role of Multidrug Resistance Protein 3 in Antifungal-Induced Cholestasis.

    Science.gov (United States)

    Mahdi, Zainab M; Synal-Hermanns, Uta; Yoker, Aylin; Locher, Kaspar P; Stieger, Bruno

    2016-07-01

    Drug-induced liver injury is an important clinical entity resulting in a considerable number of hospitalizations. While drug-induced cholestasis due to the inhibition of the bile salt export pump (BSEP) is well investigated, only limited information on the interaction of drugs with multidrug resistance protein 3 (MDR3) exists and its role in the pathogenesis of drug-induced cholestasis is poorly understood. Therefore, we aimed to study the interaction of drugs with MDR3 and the effect of drugs on canalicular lipid secretion in a newly established polarized cell line system that serves as a model of canalicular lipid secretion. LLC-PK1 cells were stably transfected with human Na(+)-taurocholate cotransporting polypeptide, BSEP, MDR3, and ABCG5/G8 and grown in the Transwell system. Apical phospholipid secretion and taurocholate transport were assayed to investigate the effect of selected drugs on MDR3-mediated phospholipid secretion as well as inhibition of BSEP. The established cell line displayed vectorial bile salt transport and specific phosphatidylcholine secretion into the apical compartment. The antifungal azoles, posaconazole, itraconazole, and ketoconazole, significantly inhibited MDR3-mediated phosphatidylcholine secretion. In contrast, amoxicillin clavulanate and troglitazone did not interfere with MDR3 activity. Drugs interfering with MDR3 activity did not display a parallel inhibition of BSEP. Our in vitro model for MDR3-mediated phospholipid secretion facilitates parallel screening for MDR3 and BSEP inhibitors. Our data demonstrate that the cholestatic potential of certain drugs may be aggravated by simultaneous inhibition of BSEP and MDR3. PMID:27112167

  18. Adverse events of modern antifungal drugs during treatment of invasive fungal infections

    Directory of Open Access Journals (Sweden)

    N. V. Dmitrieva

    2013-01-01

    Full Text Available Characteristics of adverse events of modern antimycotics by organ systems and comparative frequency between different medicines and their groups are presented. The examples of incompatibility of antifungal drugs with other pharmacological groups are discussed. Records of adverse events and drug compatibility will allow the practitioner to prevent and timely cure possible complications, should they arise.

  19. Effects of the association of antifungal drugs on the antimicrobial action of endodontic sealers

    Directory of Open Access Journals (Sweden)

    Paulo Henrique WECKWERTH

    2015-01-01

    Full Text Available This in vitro study aimed to determine the susceptibility of oral specimens and ATCC lineages of Candida albicans for five endodontic sealers, which were pure and associated with two antifungal drugs, and to analyze their effect on the physical properties. For this purpose, 30 lineages of C. albicans, collected from the oral cavity of patients assisted at the endodontics clinic of the Universidade Sagrado Coração, were analyzed. Yeasts susceptibility to the sealers was tested by diffusion on agar plates. Physical properties were evaluated according to the ADA specification no. 57. The pure versions of the Sealer 26, AH Plus, Endofill, Fillapex, and Sealapex demonstrated antifungal activity, with Endofill presenting the greatest inhibition zones. All cements, except for Endofill, had their antifungal actions enhanced by addition of ketoconazole and fluconazole (p < 0.05, and the AH Plus presented the best antifungal activity. The addition of antifungal drugs did not interfere with the setting time and flowability of the sealers. It was concluded that the addition of antifungals to endodontic sealers enhanced the antimicrobial action of most cements tested without altering their physical properties.

  20. Exploring the Molecular Basis of Antifungal Synergies Using Genome-Wide Approaches

    OpenAIRE

    Agarwal, Ameeta K.; Tripathi, Siddharth K.; Xu, Tao; Jacob, Melissa R.; Li, Xing-Cong; Clark, Alice M.

    2012-01-01

    Drug resistance poses a significant challenge in antifungal therapy since resistance has been found for all known classes of antifungal drugs. The discovery of compounds that can act synergistically with antifungal drugs is an important strategy to overcome resistance. For such combination therapies to be effective, it is critical to understand the molecular basis for the synergism by examining the cellular effects exerted by the combined drugs. Genomic profiling technologies developed in the...

  1. Drug resistance in mycobacterium tuberculosis

    OpenAIRE

    Abate, Getahun

    1999-01-01

    Drug-resistant tuberculosis is a global public health problem. This investigation was performed to find ways of improving regimens that could be used for the treatment of drug- and multidrug-resistant TB and also to find a rapid method of diagnosis of drug resistant TB, particularly MDR-TB. Among 107 isolates of M. tuberculosis from re-treatment cases of pulmonary TB in Ethiopia (study 1), 48% were resistant at least to one of the four first-line drugs tested and 12 % were A...

  2. Structural characterization of CYP51 from Trypanosoma cruzi and Trypanosoma brucei bound to the antifungal drugs posaconazole and fluconazole.

    Directory of Open Access Journals (Sweden)

    Chiung-Kuang Chen

    Full Text Available BACKGROUND: Chagas Disease is the leading cause of heart failure in Latin America. Current drug therapy is limited by issues of both efficacy and severe side effects. Trypansoma cruzi, the protozoan agent of Chagas Disease, is closely related to two other major global pathogens, Leishmania spp., responsible for leishmaniasis, and Trypansoma brucei, the causative agent of African Sleeping Sickness. Both T. cruzi and Leishmania parasites have an essential requirement for ergosterol, and are thus vulnerable to inhibitors of sterol 14alpha-demethylase (CYP51, which catalyzes the conversion of lanosterol to ergosterol. Clinically employed anti-fungal azoles inhibit ergosterol biosynthesis in fungi, and specific azoles are also effective against both Trypanosoma and Leishmania parasites. However, modification of azoles to enhance efficacy and circumvent potential drug resistance has been problematic for both parasitic and fungal infections due to the lack of structural insights into drug binding. METHODOLOGY/PRINCIPAL FINDINGS: We have determined the crystal structures for CYP51 from T. cruzi (resolutions of 2.35 A and 2.27 A, and from the related pathogen T. brucei (resolutions of 2.7 A and 2.6 A, co-crystallized with the antifungal drugs fluconazole and posaconazole. Remarkably, both drugs adopt multiple conformations when binding the target. The fluconazole 2,4-difluorophenyl ring flips 180 degrees depending on the H-bonding interactions with the BC-loop. The terminus of the long functional tail group of posaconazole is bound loosely in the mouth of the hydrophobic substrate binding tunnel, suggesting that the major contribution of the tail to drug efficacy is for pharmacokinetics rather than in interactions with the target. CONCLUSIONS/SIGNIFICANCE: The structures provide new insights into binding of azoles to CYP51 and mechanisms of potential drug resistance. Our studies define in structural detail the CYP51 therapeutic target in T. cruzi, and

  3. The expenditures related to the use of antifungal drugs in patients with hematological cancers: a cost analysis

    Directory of Open Access Journals (Sweden)

    Gedik H

    2015-11-01

    Full Text Available Habip Gedik Department of Infectious Diseases and Clinical Microbiology, Ministry of Health Okmeydani Training and Research Hospital, Istanbul, Turkey Objective: The aim of this study is to analyze the expenditures related to the use of antifungal drugs in patients with hematological malignancies. Methods: In this retrospective study, the expenditures related to use of antifungal drugs for treatment of invasive fungal infections in patients with hematological malignancies between November 2010 and November 2012 were analyzed. Expenditures of antifungal drugs were calculated by converting the price billed to the Republic of Turkey Social Security Institution per patient using the US dollar ($ exchange rate. Results: We retrospectively analyzed the expenditures related to the use of antifungal drugs in 282 febrile episodes of 126 neutropenic patients. Voriconazole (VOR, caspofungin, and liposomal amphotericin B (L-AmB were administered as a first-line antifungal therapy to treat 72 febrile episodes of 65 neutropenic patients, 45 febrile episodes of 37 neutropenic patients, and 34 febrile episodes of 32 neutropenic patients, respectively. The expenditures related to the use of antifungal drugs per febrile neutropenic episode were $3,857.85 for VOR; $15,783.34 for caspofungin, and $21,561.02 for L-AmB, respectively. The expenditure related to the use of posaconazole (POS was $32,167.39 per patient for primary or secondary prophylaxis. Conclusion: Improving conditions in the patient's room, choosing pre-emptive antifungal treatment instead of empirical antifungal treatment, switching to tablet form of VOR after initiation of its intravenous form, secondary prophylaxis with VOR against invasive aspergillosis, primary prophylaxis with POS in high-risk patients, and choosing less L-AmB as being an alternative to other antifungal drugs, may reduce expenditures related to the use of antifungal drugs in the treatment of invasive fungal infections during

  4. Drug-interactions of azole antifungals with selected immunosuppressants in transplant patients: strategies for optimal management in clinical practice

    NARCIS (Netherlands)

    Lempers, V.J.C.; Martial, L.C.; Schreuder, M.F.; Blijlevens, N.M.A.; Burger, D.M.; Aarnoutse, R.E.; Bruggemann, R.J.M.

    2015-01-01

    The management of drug-drug interactions (DDIs) between azole antifungals (fluconazole, itraconazole, posaconazole and voriconazole) and immunosuppressants (cyclosporine, tacrolimus, everolimus and sirolimus) in transplant patients remains challenging, as the impact of altered immunosuppressant conc

  5. Molecular and biochemical mechanisms of drug resistance in fungi.

    Science.gov (United States)

    Yamaguchi, H

    1999-01-01

    This paper reviews the current status of our understanding of resistance mechanisms of three major classes of antifungal drugs for systemic use, amphotericin B (AMPH), flucytosine (5-FC) and several azole antifungals, in particular fluconazole (FLCZ), at the molecular and cellular levels. Although the number of reports of AMPH- or 5-FC-resistant fungal species and strains is limited, several mechanisms of resistance have been described. AMPH-resistant Candida have a marked decrease in ergosterol content compared with AMPH-susceptible control isolates. A lesion in the UMP-pyrophosphorylase is the most frequent determinant of 5-FC resistance in C. albicans. Recently resistance of C. albicans to azoles has become an increasing problem. Extensive biochemical studies have highlighted a significant diversity in mechanisms conferring resistance to FLCZ and other azoles, which include alterations in sterol biosynthesis, target site, uptake and efflux. Among them, the most important mechanism clinically is reduced access of the drug to the intracellular P450 14 DM target, probably because of the action of a multidrug resistance efflux pump, and overproduction of that target. However, other possible resistance mechanisms for azoles remain to be identified.

  6. Structural Insights into Binding of the Antifungal Drug Fluconazole to Saccharomyces cerevisiae Lanosterol 14α-Demethylase.

    Science.gov (United States)

    Sagatova, Alia A; Keniya, Mikhail V; Wilson, Rajni K; Monk, Brian C; Tyndall, Joel D A

    2015-08-01

    Infections by fungal pathogens such as Candida albicans and Aspergillus fumigatus and their resistance to triazole drugs are major concerns. Fungal lanosterol 14α-demethylase belongs to the CYP51 class in the cytochrome P450 superfamily of enzymes. This monospanning bitopic membrane protein is involved in ergosterol biosynthesis and is the primary target of azole antifungal drugs, including fluconazole. The lack of high-resolution structural information for this drug target from fungal pathogens has been a limiting factor for the design of modified triazole drugs that will overcome resistance. Here we report the X-ray structure of full-length Saccharomyces cerevisiae lanosterol 14α-demethylase in complex with fluconazole at a resolution of 2.05 Å. This structure shows the key interactions involved in fluconazole binding and provides insight into resistance mechanisms by revealing a water-mediated hydrogen bonding network between the drug and tyrosine 140, a residue frequently found mutated to histidine or phenylalanine in resistant clinical isolates. PMID:26055382

  7. Grafting β-Cyclodextrins to Silicone, Formulation of Emulsions and Encapsulation of Antifungal Drug

    Science.gov (United States)

    Noomen, Ahlem; Penciu, Alexandra; Hbaieb, Souhaira; Parrot-Lopez, Hélène; Amdouni, Noureddine; Chevalier, Yves; Kalfat, Rafik

    Emulsions of silicone polymers having β-cyclodextrin units as lateral chains have been prepared and used for the encapsulation of the antifungal drug griseofulvin. Such technology enables the formulation of active substances that are not soluble in water as dosage forms for topical administration.

  8. Drugs reverting multidrug resistance (chemosensitizers)

    Energy Technology Data Exchange (ETDEWEB)

    Gualtieri, F. [Florence Univ. (Italy). Dip. di Scienze Farmaceutiche

    1996-12-01

    Drug resistance is a phenomenon that frequently impairs proper treatment of cancer. Multidrug resistance (MDR) is a particular case of acquired drug resistance, resulting from overexpression of a protein (P-170) that functions as a pump, clearing cells from the chemotherapic. The P-170 protein functions can be inhibited by a variety of lipophilic drugs containing a hydrophilic nitrogen, protonated at physiological pH. A considerable effort is underway to identify new drugs able to reverse MDR. Few of these molecules are already undergoing clinical trials.

  9. Type I methionine aminopeptidase from Saccharomyces cerevisiae is a potential target for antifungal drug screening

    Institute of Scientific and Technical Information of China (English)

    Ling-ling CHEN; Jia LI; Jing-ya LI; Qun-li LUO; Wei-feng MAO; Qiang SHEN; Fa-jun NAN; Qi-zhuang YE

    2004-01-01

    AIM: To screen antifungal drug candidates using in vitro and in vivo assays based on type I methionine aminopeptidase from Saccharomyces cerevisiae (ScMetAP1). METHODS: A colorimetric assay suitable for high throughput screening (HTS) using recombinant ScMetAP1 protein expressed in Escherichia coli was established for antifungal lead discovery. A series of pyridine-2-carboxylic acid derivatives were characterized and a chemical library of 12 800 pure organic compounds was screened with the in vitro ScMetAP1 assay. Active compounds from the in vitro assay were further evaluated by a growth inhibition assay on yeast strain with deletion of ScMetAP1 gene mapl in comparison with the wild-type yeast strain and the yeast strain with deletion of type II enzyme (ScMetAP2)gene map2. RESULTS: Active ScMetAP1 inhibitors were identified from HTS. Some of the pyridine-2-carboxylic acid derivatives (compound 2 and 3) had selective inhibition of the growth of map2 deletion yeast and weak inhibition on wild-type yeast growth, while no inhibition on mapl deletion yeast. CONCLUSION: ScMetAP1 is a novel potential target for developing antifungal drugs. The in vitro and in vivo ScMetAP1 assays can serve as tools in discovering antifungal drug candidates.

  10. Characterisation of the Candida albicans Phosphopantetheinyl Transferase Ppt2 as a Potential Antifungal Drug Target.

    Directory of Open Access Journals (Sweden)

    Katharine S Dobb

    Full Text Available Antifungal drugs acting via new mechanisms of action are urgently needed to combat the increasing numbers of severe fungal infections caused by pathogens such as Candida albicans. The phosphopantetheinyl transferase of Aspergillus fumigatus, encoded by the essential gene pptB, has previously been identified as a potential antifungal target. This study investigated the function of its orthologue in C. albicans, PPT2/C1_09480W by placing one allele under the control of the regulatable MET3 promoter, and deleting the remaining allele. The phenotypes of this conditional null mutant showed that, as in A. fumigatus, the gene PPT2 is essential for growth in C. albicans, thus fulfilling one aspect of an efficient antifungal target. The catalytic activity of Ppt2 as a phosphopantetheinyl transferase and the acyl carrier protein Acp1 as a substrate were demonstrated in a fluorescence transfer assay, using recombinant Ppt2 and Acp1 produced and purified from E.coli. A fluorescence polarisation assay amenable to high-throughput screening was also developed. Therefore we have identified Ppt2 as a broad-spectrum novel antifungal target and developed tools to identify inhibitors as potentially new antifungal compounds.

  11. Rapid identification of antifungal compounds against Exserohilum rostratum using high throughput drug repurposing screens.

    Directory of Open Access Journals (Sweden)

    Wei Sun

    Full Text Available A recent large outbreak of fungal infections by Exserohilum rostratum from contaminated compounding solutions has highlighted the need to rapidly screen available pharmaceuticals that could be useful in therapy. The present study utilized two newly-developed high throughput assays to screen approved drugs and pharmaceutically active compounds for identification of potential antifungal agents. Several known drugs were found that have potent effects against E. rostratum including the triazole antifungal posaconazole. Posaconazole is likely to be effective against infections involving septic joints and may provide an alternative for refractory central nervous system infections. The anti-E. rostratum activities of several other drugs including bithionol (an anti-parasitic drug, tacrolimus (an immunosuppressive agent and floxuridine (an antimetabolite were also identified from the drug repurposing screens. In addition, activities of other potential antifungal agents against E. rostratum were excluded, which may avoid unnecessary therapeutic trials and reveals the limited therapeutic alternatives for this outbreak. In summary, this study has demonstrated that drug repurposing screens can be quickly conducted within a useful time-frame. This would allow clinical implementation of identified alternative therapeutics and should be considered as part of the initial public health response to new outbreaks or rapidly-emerging microbial pathogens.

  12. Hsp90 governs dispersion and drug resistance of fungal biofilms.

    Directory of Open Access Journals (Sweden)

    Nicole Robbins

    2011-09-01

    Full Text Available Fungal biofilms are a major cause of human mortality and are recalcitrant to most treatments due to intrinsic drug resistance. These complex communities of multiple cell types form on indwelling medical devices and their eradication often requires surgical removal of infected devices. Here we implicate the molecular chaperone Hsp90 as a key regulator of biofilm dispersion and drug resistance. We previously established that in the leading human fungal pathogen, Candida albicans, Hsp90 enables the emergence and maintenance of drug resistance in planktonic conditions by stabilizing the protein phosphatase calcineurin and MAPK Mkc1. Hsp90 also regulates temperature-dependent C. albicans morphogenesis through repression of cAMP-PKA signalling. Here we demonstrate that genetic depletion of Hsp90 reduced C. albicans biofilm growth and maturation in vitro and impaired dispersal of biofilm cells. Further, compromising Hsp90 function in vitro abrogated resistance of C. albicans biofilms to the most widely deployed class of antifungal drugs, the azoles. Depletion of Hsp90 led to reduction of calcineurin and Mkc1 in planktonic but not biofilm conditions, suggesting that Hsp90 regulates drug resistance through different mechanisms in these distinct cellular states. Reduction of Hsp90 levels led to a marked decrease in matrix glucan levels, providing a compelling mechanism through which Hsp90 might regulate biofilm azole resistance. Impairment of Hsp90 function genetically or pharmacologically transformed fluconazole from ineffectual to highly effective in eradicating biofilms in a rat venous catheter infection model. Finally, inhibition of Hsp90 reduced resistance of biofilms of the most lethal mould, Aspergillus fumigatus, to the newest class of antifungals to reach the clinic, the echinocandins. Thus, we establish a novel mechanism regulating biofilm drug resistance and dispersion and that targeting Hsp90 provides a much-needed strategy for improving

  13. Curcumin and its promise as an anticancer drug: An analysis of its anticancer and antifungal effects in cancer and associated complications from invasive fungal infections.

    Science.gov (United States)

    Chen, Jin; He, Zheng-Min; Wang, Feng-Ling; Zhang, Zheng-Sheng; Liu, Xiu-zhen; Zhai, Dan-Dan; Chen, Wei-Dong

    2016-02-01

    Invasive fungal infections (IFI) are important complications of cancer, and they have become a major cause of morbidity and mortality in cancer patients. Effective anti-infection therapy is necessary to inhibit significant deterioration from these infections. However, they are difficult to treat, and increasing antifungal drug resistance often leads to a relapse. Curcumin, a natural component that is isolated from the rhizome of Curcuma longa plants, has attracted great interest among many scientists studying solid cancers over the last half century. Interestingly, curcumin provides an ideal alternative to current therapies because of its relatively safe profile, even at high doses. To date, curcumin's potent antifungal activity against different strains of Candida, Cryptococcus, Aspergillus, Trichosporon and Paracoccidioides have been reported, indicating that curcumin anticancer drugs may also possess an antifungal role, helping cancer patients to resist IFI complications. The aim of this review is to discuss curcumin's dual pharmacological activities regarding its applications as a natural anticancer and antifungal agent. These dual pharmacological activities are expected to lead to clinical trials and to improve infection survival among cancer patients. PMID:26723514

  14. Transgenic maize plants expressing the Totivirus antifungal protein, KP4, are highly resistant to corn smut.

    Science.gov (United States)

    Allen, Aron; Islamovic, Emir; Kaur, Jagdeep; Gold, Scott; Shah, Dilip; Smith, Thomas J

    2011-10-01

    The corn smut fungus, Ustilago maydis, is a global pathogen responsible for extensive agricultural losses. Control of corn smut using traditional breeding has met with limited success because natural resistance to U. maydis is organ specific and involves numerous maize genes. Here, we present a transgenic approach by constitutively expressing the Totivirus antifungal protein KP4, in maize. Transgenic maize plants expressed high levels of KP4 with no apparent negative impact on plant development and displayed robust resistance to U. maydis challenges to both the stem and ear tissues in the greenhouse. More broadly, these results demonstrate that a high level of organ independent fungal resistance can be afforded by transgenic expression of this family of antifungal proteins.

  15. Antimicrobial (Drug) Resistance: Gonorrhea

    Science.gov (United States)

    ... Marketing Share this: Main Content Area Multidrug-Resistant Neisseria gonorrhoeae (Gonorrhea) During the past 50 years, the use ... Gonorrhea is a sexually transmitted disease caused by Neisseria gonorrhoeae , a bacterium that can infect areas of the ...

  16. The expenditures related to the use of antifungal drugs in patients with hematological cancers: a cost analysis

    OpenAIRE

    Gedik H

    2015-01-01

    Habip Gedik Department of Infectious Diseases and Clinical Microbiology, Ministry of Health Okmeydani Training and Research Hospital, Istanbul, Turkey Objective: The aim of this study is to analyze the expenditures related to the use of antifungal drugs in patients with hematological malignancies. Methods: In this retrospective study, the expenditures related to use of antifungal drugs for treatment of invasive fungal infections in patients with hematological malignancies between November 20...

  17. [Derivatization of berberine based on its synergistic antifungal activity with fluconazole against fluconazole-resistant Candida albicans].

    Science.gov (United States)

    Tian, Shu-Juan; Gao, Yue; Zang, Cheng-Xu; Cai, Zhan; Ni, Ting-jun-hong; Tan, Shan-Lun; Cao, Yong-Bing; Jiang, Yuan-Ying; Zhang, Da-Zhi

    2014-11-01

    Abstract: Our previous work revealed berberine can significantly enhance the susceptibility of fluconazole against fluconazole-resistant Candida albicans, which suggested that berberine has synergistic antifungal activity with fluconazole. Preliminary SAR of berberine needs to be studied for the possibility of investigating its target and SAR, improving its drug-likeness, and exploring new scaffold. In this work, 13-substitutited benzyl berberine derivatives and N-benzyl isoquinoline analogues were synthesized and characterized by 1H NMR and MS. Their synergetic activity with fluconazole against fluconazole-resistant Candida albicans was evaluated in vitro. The 13-substitutited benzyl berberine derivatives 1a-1e exhibited comparable activity to berberine, which suggested that the introduction of functional groups to C-13 can maintain its activity. The N-benzyl isoquinolines, which were designed as analogues of berberine with its D ring opened, exhibited lower activity than berberine. However, compound 2b, 2c, and 4b showed moderate activity, which indicated that berberine may be deconstructed to new scaffold with synergistic antifungal activity with fluconazole. The results of our research may be helpful to the SAR studies on its other biological activities.

  18. Antiviral Drug Resistance: Mechanisms and Clinical Implications

    OpenAIRE

    Strasfeld, Lynne; Chou, Sunwen

    2010-01-01

    Antiviral drug resistance is an increasing concern in immunocompromised patient populations, where ongoing viral replication and prolonged drug exposure lead to the selection of resistant strains. Rapid diagnosis of resistance can be made by associating characteristic viral mutations with resistance to various drugs as determined by phenotypic assays. Management of drug resistance includes optimization of host factors and drug delivery, selection of alternative therapies based on knowledge of...

  19. Extensively drug-resistant tuberculosis.

    Science.gov (United States)

    Jassal, Mandeep; Bishai, William R

    2009-01-01

    Extensively drug-resistant (XDR) tuberculosis is defined as disease caused by Mycobacterium tuberculosis with resistance to at least isoniazid and rifampicin, any fluoroquinolone, and at least one of three injectable second-line drugs (amikacin, capreomycin, or kanamycin). The definition has applicable clinical value and has allowed for more uniform surveillance in varied international settings. Recent surveillance data have indicated that the prevalence of tuberculosis drug resistance has risen to the highest rate ever recorded. The gold standard for drug-susceptibility testing has been the agar proportion method; however, this technique requires several weeks for results to be determined. More sensitive and specific diagnostic tests are still unavailable in resource-limited settings. Clinical manifestations, although variable in different settings and among different strains, have in general shown that XDR tuberculosis is associated with greater morbidity and mortality than non-XDR tuberculosis. The treatment of XDR tuberculosis should include agents to which the organism is susceptible, and should continue for a minimum of 18-24 months. However, treatment continues to be limited in tuberculosis-endemic countries largely because of weaknesses in national tuberculosis health-care models. The ultimate strategy to control drug-resistant tuberculosis is one that implements a comprehensive approach incorporating innovation from the political, social, economic, and scientific realms. PMID:18990610

  20. Lamisil, a potent alternative antifungal drug for otomycosis

    Directory of Open Access Journals (Sweden)

    Ali Zarei Mahmoudabadi

    2015-01-01

    Results: Out of 23 isolates of Aspergillus, Candida 4(17.4% and 1(4.4% were resistant to nystatin and miconazole, respectively. In addition, all tested organisms were sensitive to clotrimazole and terbinafine. Statistical analysis has shown that there are no significant differences on the effects of clotrimazole, miconazole and, terbinafine on saprophytic (environmental and pathogenic isolates of A. niger, A. flavus, and A. terreus (P value= 0.85. In addition, all tested organisms were found to be highly susceptible to terbinafine (P< 0.04. Conclusion: This is a new approach for the possible use of Lamisil for the treatment of otomycosis.

  1. Antifungal susceptibility of Malassezia pachydermatis biofilm.

    Science.gov (United States)

    Figueredo, Luciana A; Cafarchia, Claudia; Otranto, Domenico

    2013-11-01

    Antifungal resistance has been associated with biofilm formation in many microorganisms, but not yet in Malassezia pachydermatis. This saprophytic yeast can cause otitis and dermatitis in dogs and has emerged as an important human pathogen, responsible for systemic infections in neonates in intensive care units. This study aims to evaluate the in vitro antifungal susceptibility of M. pachydermatis strains, in both their planktonic and sessile forms, to fluconazole, miconazole, ketoconazole, itraconazole, posaconazole, terbinafine and voriconazole using the XTT assay and Clinical and Laboratory Standards Institute (CLSI) microdilution method. The minimum inhibitory concentration (MIC) values recorded for each drug were significantly higher for sessile cells relative to planktonic cells to the extent that ≥ 90% of M. pachydermatis strains in their sessile form were classified as resistant to all antifungal agents tested. Data suggest that M. pachydermatis biofilm formation is associated with antifungal resistance, paving the way towards investigating drug resistance mechanisms in Malassezia spp. PMID:23834283

  2. Posttreatment Antifungal Resistance among Colonizing Candida Isolates in Candidemia Patients

    DEFF Research Database (Denmark)

    Jensen, R H; Johansen, H K; Søes, L M;

    2016-01-01

    isolates (36.6% versus 12.9%; P 0.5). Acquired resistance in Candida albicans was rare (...The prevalence of intrinsic and acquired resistance among colonizing Candida isolates from patients after candidemia was investigated systematically in a 1-year nationwide study. Patients were treated at the discretion of the treating physician. Oral swabs were obtained after treatment. Species...... analysis demonstrated a genetic relationship for 90% of all paired blood and oral isolates. Patients exposed to azoles for ≥ 7 days (n = 93) had a significantly larger proportion of species intrinsically less susceptible to azoles (particularly Candida glabrata) among oral isolates than among initial blood...

  3. Analysis toward innovative herbal antibacterial and antifungal drugs.

    Science.gov (United States)

    Dhankhar, Sandeep; Dhankhar, Seema; Kumar, Manish; Ruhil, Sonam; Balhara, Meenakshi; Chhillar, Anil K

    2012-12-01

    The antimicrobial activities of four medicinal plants Argemona mexicana, Achyranthes aspera, Catharanthus roseus, and Syzygium cumini were evaluated against Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae, Proteus vulgaris, Bacillus subtilis, Salmonella typhi and three Aspergillus species. Extracts from Achyranthes aspera and Catharanthus roseus showed the highest antimicrobial potential (MIC 0.375-0.750 mg/ml) while extract from Argemona mexicana and Syzygium cumini, showed less activity. In disc diffusion assay, only eight out of twenty extracts showed antimicrobial activity at a concentration of 25.0 μg/ disc. The GCMS investigation reveals the existence of 2-bornanone; 1, 2-benzenedicarboxylic acid, bis (2-methylpropyl) ester; hexadecanoic acid, methyl ester and hexatriacontane in water extract fraction of C. roseus. The present research article provides a review of some medicinal plants incorporating antimicrobial drugs, together with recent advances in emerging therapeutics in clinical development and related patents for exploitation of herbal medicine. PMID:23072646

  4. Multifactorial analysis of effects of interactions among antifungal and antineoplastic drugs on inhibition of Candida albicans growth.

    OpenAIRE

    Ghannoum, M. A.; Motawy, M S; Abu Hatab, M A; Ibrahim, A.S.; Criddle, R. S.

    1989-01-01

    Interactions among antineoplastic and antifungal drugs affecting the inhibition of Candida albicans growth are complex functions of the nature of the drugs used in combination, their absolute concentrations, and also their relative concentrations. Studies of drug interactions involving the use of test drugs in fixed concentration ratios can lead to inaccurate conclusions about synergism or antagonism among the drugs. A multifactorial experimental design procedure in which the concentrations o...

  5. Emergence of non-albicans Candida species and antifungal resistance in intensive care unit patients

    Institute of Scientific and Technical Information of China (English)

    Ravinder Kaur; Megh Singh Dhakad; Ritu Goyal; Rakesh Kumar

    2016-01-01

    Objective: To evaluate the epidemiology of candidiasis and the antifungal susceptibility profile of Candida species isolated from the intensive care unit (ICU) patients. Methods: The study used a qualitative descriptive design. Relevant samples depending on organ system involvement from 100 ICU patients were collected and processed. Identification and speciation of the isolates was conducted by the biochemical tests. Antifungal susceptibility testing was carried out as per CLSI-M27-A3 document. Results: Ninety Candida isolates were isolated from the different clinical samples:urine (43.3%), tracheal aspirate (31.1%), urinary catheter (12.2%), endotracheal tube (7.8%), abdominal drains (3.3%), sputum (2.2%). The incidence of candidiasis caused by non-albicans Candida (NAC) species (63.3%) was higher than Candida albicans (36.7%). The various NAC species were isolated as: Candida tropicalis (41.1%), Candida glab-rata (10%), Candida parapsilosis (6.7%), Candida krusei (3.3%) and Candida kefyr (2.2%). The overall isolation rate of Candida species from samples was 53.3%. Anti-fungal susceptibility indicated that 37.8%and 7.8%of the Candida isolates were resistant to fluconazole and amphotericin B, respectively. Conclusions: Predominance of NAC species in ICU patients along with the increasing resistance being recorded to fluconazole which has a major bearing on the morbidity and management of these patients and needs to be further worked upon.

  6. Enhancing disease resistances of Super Hybrid Rice with four antifungal genes

    Institute of Scientific and Technical Information of China (English)

    ZHU HuaChen; XU XinPing; XIAO GuoYing; YUAN LongPing; LI BaoJian

    2007-01-01

    A plant expression vector harboring four antifungal genes was delivered into the embryogenic calli of '9311', an indica restorer line of Super Hybrid Rice, via modified biolistic particle bombardment. Southern blot analysis indicated that in the regenerated hygromycin-resistant plants, all the four antifungal genes, including RCH10, RAC22, β-Glu and B-RIP, were integrated into the genome of '9311', co-transmitted altogether with the marker gene hpt in a Mendelian pattern. Some transgenic R1 and R2 progenies, with all transgenes displaying a normal expression level in the Northern blot analysis, showed high resistance to Magnaporthe grisea when tested in the typical blast nurseries located in Yanxi and Sanya respectively. Furthermore, transgenic F1 plants, resulting from a cross of R2 homozygous lines with high resistance to rice blast with the non-transgenic male sterile line Peiai 64S, showed not only high resistance to M. grisea but also enhanced resistance to rice false smut (a disease caused by Ustilaginoidea virens) and rice kernel smut (another disease caused by Tilletia barclayana).

  7. Enhancing disease resistances of Super Hybrid Rice with four antifungal genes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A plant expression vector harboring four antifungal genes was delivered into the embryogenic calli of ‘9311’, an indica restorer line of Super Hybrid Rice, via modified biolistic particle bombardment. Southern blot analysis indicated that in the regenerated hygromycin-resistant plants, all the four anti-fungal genes, including RCH10, RAC22, β-Glu and B-RIP, were integrated into the genome of ‘9311’, co-transmitted altogether with the marker gene hpt in a Mendelian pattern. Some transgenic R1 and R2 progenies, with all transgenes displaying a normal expression level in the Northern blot analysis, showed high resistance to Magnaporthe grisea when tested in the typical blast nurseries located in Yanxi and Sanya respectively. Furthermore, transgenic F1 plants, resulting from a cross of R2 homo-zygous lines with high resistance to rice blast with the non-transgenic male sterile line Peiai 64S, showed not only high resistance to M. grisea but also enhanced resistance to rice false smut (a disease caused by Ustilaginoidea virens) and rice kernel smut (another disease caused by Tilletia barclayana).

  8. Biodirected synthesis of Miconazole-conjugated bacterial silver nanoparticles and their application as antifungal agents and drug delivery vehicles.

    Science.gov (United States)

    Kumar, C Ganesh; Poornachandra, Y

    2015-01-01

    The recent strategy to improve the efficacy of drugs is to combine them with metal nanoparticles for the control of microbial infections. Considering this fact, we developed a low cost and eco-friendly method for silver nanoparticles synthesis using the cell free supernatant of Delftia sp. strain KCM-006 and their application as antifungal agents and as a drug carrier. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis revealed the formation of spherical and monodispersed silver nanoparticles with an average size of 9.8 nm. The synthesized nanoparticles were found to be photoluminescent, highly stable and crystalline in nature having a zeta potential of -31 mV. The silver nanoparticles exhibited very good antifungal activity against various pathogenic Candida strains. Furthermore, the efficacy of nanoparticles was increased by conjugating the antifungal drug Miconazole to silver nanoparticles which exhibited significant fungicidal activity, inhibition of ergosterol biosynthesis and biofilm inhibition by increasing ROS levels. In addition, the cell viability and immunocytochemistry analysis against different normal cell lines including Chinese hamster ovary cells (CHO), human lung cell line (MRC5) and human vascular endothelial cells (HUVEC) demonstrated that these nanoparticles were non-toxic up to a concentration of 20 μM. In conclusion, these results suggest that the synthesized nanoparticles find application as both antifungal agents and drug delivery vehicles. This is a first report on the preparation of silver nanoparticles using culture supernatant from Delftia sp. and also on the conjugation of Miconazole, an antifungal drug, to the bacterial silver nanoparticles.

  9. Measurement and correlation of antifungal drugs solubility in pure supercritical CO2 using semiempirical models

    International Nuclear Information System (INIS)

    Highlights: → Ketoconazole (KZ) and clotrimazole (CZ) are two antifungal drugs. → The solubilities of KZ and CZ were measured in supercritical CO2. → The experimental results were correlated using five density based models. → The heats' of drug-CO2 solvation and drug vaporization were estimated. - Abstract: In the present study the solubilities of two antifungal drugs of ketoconazole and clotrimazole in supercritical carbon dioxide were measured using a simple static method. The experimental data were measured at (308 to 348) K, over the pressure range of (12.2 to 35.5) MPa. The mole fraction solubilities ranged from 0.2 . 10-6 to 17.45 . 10-5. In this study five density based models were used to calculate the solubility of drugs in supercritical carbon dioxide. The density based models are Chrastil, modified Chrastil, Bartle, modified Bartle and Mendez-Santiago and Teja (M-T). Interaction parameters for the studied models were obtained and the percentage of average absolute relative deviation (AARD%) in each calculation was displayed. The correlation results showed good agreement with the experimental data. A comparison among the five models revealed that the Bartle and its modified models gave much better correlations of the solubility data with an average absolute relative deviation (AARD%) ranging from 4.8% to 6.2% and from 4.5% to 6.3% for ketoconazole and clotrimazole, respectively. Using the correlation results, the heat of drug-CO2 solvation and that of drug vaporization was separately approximated in the range of (-22.1 to -26.4 and 88.3 to 125.9) kJ . mol-1.

  10. Analysis of drug sensitivity of candida to antifungal drugs in 152 infected patients%152例临床念珠菌感染药敏分析

    Institute of Scientific and Technical Information of China (English)

    奚琳琳; 张群智; 李芳芹

    2011-01-01

    目的 了解医院念珠菌感染药敏情况,为临床合理用药提供实验依据.方法 从临床标本中分离培养念珠菌,进行鉴定和药敏试验.结果 1 538份临床标本中分离出念珠菌152株(9.88%);其中,白色念珠菌111株(73.03%),克柔氏念珠菌31例(20.39%),其他10(6.58%).白色念珠菌时常用抗真菌药物敏感性均较高(伊曲康唑除外),而克柔氏念珠菌则对常用抗真菌药物均有较高的敏感率.结论 白色念珠菌和克柔氏念珠菌对临床一线抗真菌药氟康哇存在耐药株,应重视对高危人群进行微生物学检测和药敏试验.%Aim To investigate drug sensitivity of candida to antibiotics in patients with candida infection.Methods Candida were isolated and cultured from clinical 152 and drug sensitivity of candida to antifungal was conducted and the results were analyzed.Results A total of 152 (9.88%)candida strains were isolated from 1 538 samples,including 111 (73.03%)Candida albicans and 31 (20.39%)Candida krusei.Candida albicans showed higher sensitive rates to conventional antifungal drugs except itraconazole.However,Candida krusei showed higher sensitive rates to antifungal agents.Conclusion Candida albicans and Candida krusei showed resistances to clinical first-line antffuangal drugs such as fluconazole.Thus srug sensitivity tests be carried out to guide clinical treatment of the infections

  11. Ethosomes: a novel delivery system for antifungal drugs in the treatment of topical fungal diseases.

    Science.gov (United States)

    Bhalaria, M K; Naik, Sachin; Misra, A N

    2009-05-01

    Aim of this work was to prepare and characterize fluconazole (FLZ) encapsulated ethosomes, incorporate it in suitable dermatological base, and asses its comparative clinical efficacy in the treatment of Candidiasis patients against liposomal gel, marketed product and hydroethanolic solution of the drug. Drug encapsulated ethosomes and liposomes were prepared and optimized by "Hot" method technique and lipid film hydration technique. Vesicular carriers were characterized for % entrapment efficiency, particle size and shape, in vitro drug diffusion study, mean % reduction in dimension of Candidiasis lesion and stability study by using suitable analytical technique. Vesicle size and drug entrapment efficiency of the optimized ethosomes and liposomes were found to be 144 +/- 6.8 nm and 82.68% and 216 +/- 9.2 nm and 68.22% respectively. Microscopic examinations suggest ethosomes to be multilamellar spherical vesicles with a smooth surface. The differential scanning calorimetry results suggest high fluidity of the ethosomes than liposomes. In vitro drug diffusion studies demonstrated that % drug diffused from ethosomes was nearly twice than liposomes and three times higher than the hydroethanolic solution across rat skin. From the clinical evaluation, the developed novel delivery system demonstrated enhanced antifungal activity compared to liposomal formulation, marketed formulation and hydroethanolic solution of the drug.

  12. Ethosomes: a novel delivery system for antifungal drugs in the treatment of topical fungal diseases.

    Science.gov (United States)

    Bhalaria, M K; Naik, Sachin; Misra, A N

    2009-05-01

    Aim of this work was to prepare and characterize fluconazole (FLZ) encapsulated ethosomes, incorporate it in suitable dermatological base, and asses its comparative clinical efficacy in the treatment of Candidiasis patients against liposomal gel, marketed product and hydroethanolic solution of the drug. Drug encapsulated ethosomes and liposomes were prepared and optimized by "Hot" method technique and lipid film hydration technique. Vesicular carriers were characterized for % entrapment efficiency, particle size and shape, in vitro drug diffusion study, mean % reduction in dimension of Candidiasis lesion and stability study by using suitable analytical technique. Vesicle size and drug entrapment efficiency of the optimized ethosomes and liposomes were found to be 144 +/- 6.8 nm and 82.68% and 216 +/- 9.2 nm and 68.22% respectively. Microscopic examinations suggest ethosomes to be multilamellar spherical vesicles with a smooth surface. The differential scanning calorimetry results suggest high fluidity of the ethosomes than liposomes. In vitro drug diffusion studies demonstrated that % drug diffused from ethosomes was nearly twice than liposomes and three times higher than the hydroethanolic solution across rat skin. From the clinical evaluation, the developed novel delivery system demonstrated enhanced antifungal activity compared to liposomal formulation, marketed formulation and hydroethanolic solution of the drug. PMID:19579803

  13. Early State Research on Antifungal Natural Products

    Directory of Open Access Journals (Sweden)

    Melyssa Negri

    2014-03-01

    Full Text Available Nosocomial infections caused by fungi have increased greatly in recent years, mainly due to the rising number of immunocompromised patients. However, the available antifungal therapeutic arsenal is limited, and the development of new drugs has been slow. Therefore, the search for alternative drugs with low resistance rates and fewer side effects remains a major challenge. Plants produce a variety of medicinal components that can inhibit pathogen growth. Studies of plant species have been conducted to evaluate the characteristics of natural drug products, including their sustainability, affordability, and antimicrobial activity. A considerable number of studies of medicinal plants and alternative compounds, such as secondary metabolites, phenolic compounds, essential oils and extracts, have been performed. Thus, this review discusses the history of the antifungal arsenal, surveys natural products with potential antifungal activity, discusses strategies to develop derivatives of natural products, and presents perspectives on the development of novel antifungal drug candidates.

  14. Usefulness of Defined Daily Dose and Days of Therapy in Pediatrics and Obstetrics-Gynecology: A Comparative Analysis of Antifungal Drugs (2000–2001, 2005–2006, and 2010–2011)

    OpenAIRE

    Guillot, Justine; Lebel, Denis; Roy, Hélène; Ovetchkine, Philippe; Bussières, Jean-François

    2014-01-01

    OBJECTIVES: The objective was to describe antifungal drug use by using the number of defined daily doses (DDD)/1000 patient-days per antifungal, the number of days of therapy (DOT)/1000 patient-days per antifungal, and the mean dose in mg/kg/day per antifungal during a 10-year period.

  15. Hollow polycaprolactone composite fibers for controlled magnetic responsive antifungal drug release.

    Science.gov (United States)

    Wang, Baolin; Zheng, Hongxia; Chang, Ming-Wei; Ahmad, Zeeshan; Li, Jing-Song

    2016-09-01

    Hollow magnetic fibers for trigger based drug release were synthesized using one-step co-axial electrospinning (COX-ES). This was achieved by encapsulating the antifungal active 'ketoconazole' (KCZ) and iron oxide (Fe3O4) nanoparticles (NPs) in composite form within the core shell polymeric matrix material (polycaprolactone, PCL) during the COX-ES process. Dimethyl silicone oil was used as the inner core (liquid) of co-flowing solutions, which subsequently perfused out of the two-phase electrospun microstructures to form hollow fibers. Resulting drug-loaded magnetic hollow fibers were characterized using optical microscopy, scanning electron microscopy and Fourier Transform Infra-Red. The tensile strength and magnetization properties of composite fibers were also assessed. KCZ drug concentration in electrospinning solutions strongly influenced resulting fiber morphology, drug loading efficiency and release. Expedited drug release during a slow-sustained phase was demonstrated through the application of an auxiliary magnetic field. Variations in tensile strength (∼1.3-6.3MPa) were due to composite fiber components compromising polymer chain integrity. In-vitro cell studies (using human cervical carcinoma cell lines) demonstrated fiber biocompatibility. The present study demonstrates the potential application of magnetic hollow fibers for controlled treatment of fungal infections and antimicrobial indications. PMID:27295492

  16. Antifungal susceptibility of clinical and environmental isolates of Cryptococcus neoformans to four antifungal drugs determined by two techniques.

    Science.gov (United States)

    Moraes, E M P; Prímola, N S; Hamdan, Júnia Soares

    2003-06-01

    A total of 64 Cryptococcus neoformans strains, including clinical and environmental Brazilian isolates var. neoformans and var. gattii, were tested for susceptibility to amphotericin B, 5-flucytosine, fluconazole and itraconazole. The tests were performed according to the recommendations of National Committee of Clinical Laboratory Standards and the method of macrodilution in liquid medium of Shadomy et al. [Manual de Microbiologia Clínica, 4th ed. Buenos Aires: Editorial Medica Panamericana, 1987: 1229-38]. For most drugs there was a significant difference between the readings taken at 24 and 48 h with both methods. When the minimum inhibitory concentrations obtained by the two techniques were compared, significant differences were observed for amphotericin B and fluconazole. Overall, differences in drug susceptibility with respect to the origin of the isolates or the variety of the fungus were not observed. As an exception, the gattii variety exhibited a high resistance rate to amphotericin B when the technique of Shadomy et al. was applied, a fact possibly related to the greater difficulty for treatment of the disease caused by this fungal variety.

  17. Epidemiology and antifungal resistance in invasive aspergillosis according to primary disease - review of the literature

    Directory of Open Access Journals (Sweden)

    Mayr A

    2011-04-01

    Full Text Available Abstract Aspergilli, less susceptible to antifungals emerge and resistance to azoles have been found mainly in Aspergillus fumigatus; this has launched a new phase in handling aspergillosis. Resistant strains have currently been reported from Belgium, Canada, China, Denmark, France, Norway, Spain, Sweden, The Netherlands, UK and the USA. Centres in the UK (Manchester and The Netherlands (Nijmegen have described particularly high frequencies (15 and 10% respectively, and a significant increase in azole resistance in recent years. The reason of this high incidence may be due to long term azole therapy in patients with chronic aspergillosis in Manchester, and due to high use of agricultural azoles in Nijmegen. The primary underlying mechanism of resistance is as a result of alterations in the cyp51A target gene, with a variety of mutations found in clinical isolates and one genotype identified in the environmental (LH98. Reports on well documented in vitro and in vivo resistance to echinocandins are rare for Aspergillus species and resistance may be under-diagnosed as susceptibility testing is less frequently performed due to technical reasons.

  18. Increased chitin biosynthesis contributes to the resistance of Penicillium polonicum against the antifungal protein PgAFP.

    Science.gov (United States)

    Delgado, Josué; Owens, Rebecca A; Doyle, Sean; Asensio, Miguel A; Núñez, Félix

    2016-01-01

    Antifungal proteins from molds have been proposed as a valuable tool against unwanted molds, but the resistance of some fungi limits their use. Resistance to antimicrobial peptides has been suggested to be due to lack of interaction with the mold or to a successful response. The antifungal protein PgAFP produced by Penicillium chrysogenum inhibits the growth of various ascomycetes, but not Penicillium polonicum. To study the basis for resistance to this antifungal protein, localization of PgAFP and metabolic, structural, and morphological changes were investigated in P. polonicum. PgAFP bound the outer layer of P. polonicum but not regenerated chitin, suggesting an interaction with specific molecules. Comparative two-dimensional gel electrophoresis (2D-PAGE) and comparative quantitative proteomics revealed changes in the relative abundance of several proteins from ribosome, spliceosome, metabolic, and biosynthesis of secondary metabolite pathways. The proteome changes and an altered permeability reveal an active reaction of P. polonicum to PgAFP. The successful response of the resistant mold seems to be based on the higher abundance of protein Rho GTPase Rho1 that would lead to the increased chitin deposition via cell wall integrity (CWI) signaling pathway. Thus, combined treatment with chitinases could provide a complementary means to combat resistance to antifungal proteins.

  19. Natural and synthetic peptides with antifungal activity.

    Science.gov (United States)

    Ciociola, Tecla; Giovati, Laura; Conti, Stefania; Magliani, Walter; Santinoli, Claudia; Polonelli, Luciano

    2016-08-01

    In recent years, the increase of invasive fungal infections and the emergence of antifungal resistance stressed the need for new antifungal drugs. Peptides have shown to be good candidates for the development of alternative antimicrobial agents through high-throughput screening, and subsequent optimization according to a rational approach. This review presents a brief overview on antifungal natural peptides of different sources (animals, plants, micro-organisms), peptide fragments derived by proteolytic cleavage of precursor physiological proteins (cryptides), synthetic unnatural peptides and peptide derivatives. Antifungal peptides are schematically reported based on their structure, antifungal spectrum and reported effects. Natural or synthetic peptides and their modified derivatives may represent the basis for new compounds active against fungal infections. PMID:27502155

  20. Yeasts from the oral cavity of children with AIDS: exoenzyme production and antifungal resistance

    Directory of Open Access Journals (Sweden)

    Bosco Vera Lúcia

    2003-01-01

    Full Text Available The oral fungal microbiota of 30 children with AIDS, of both genders, aged from two to six years, receiving outpatient treatment, was evaluated and compared with that of a control group composed of 30 healthy subjects with matching ages and genders. Virulence factors, such as exoenzyme production, and susceptibility to five antifungal agents using an E-Test kit were evaluated. C. albicans predominated over other species in the AIDS group, showing a higher production of proteinase and phospholipase when compared with that observed in the control group. In this study few clinical manifestations of and low selectivity for C. albicans (23.3% were observed in the AIDS group. The enzymatic studies showed that 53.8% of the AIDS strains were strongly positive whereas only 33.3% of the non-AIDS strains were positive. Amphotericin B was the most effective drug among the antifungal agents tested against C. albicans. The frequency, selectivity and level of exoenzyme production by C. albicans suggest a higher pathogenicity in the AIDS children than in the control children.

  1. Understanding drug resistance in human intestinal protozoa.

    Science.gov (United States)

    El-Taweel, Hend Aly

    2015-05-01

    Infections with intestinal protozoa continue to be a major health problem in many areas of the world. The widespread use of a limited number of therapeutic agents for their management and control raises concerns about development of drug resistance. Generally, the use of any antimicrobial agent should be accompanied by meticulous monitoring of its efficacy and measures to minimize resistance formation. Evidence for the occurrence of drug resistance in different intestinal protozoa comes from case studies and clinical trials, sometimes with a limited number of patients. Large-scale field-based assessment of drug resistance and drug sensitivity testing of clinical isolates are needed. Furthermore, the association of drug resistance with certain geographic isolates or genotypes deserves consideration. Drug resistance has been triggered in vitro and has been linked to modification of pyruvate:ferredoxin oxidoreductase, nitroreductases, antioxidant defense, or cytoskeletal system. Further mechanistic studies will have important implications in the development of second generation therapeutic agents.

  2. Drug-resistant tuberculosis in Sindh

    International Nuclear Information System (INIS)

    Objective: To assess the prevalence of primary and secondary drug resistance amongst the clinical isolates of M.tuberculosis, to identify risk factors and how to overcome this problem. Design: A case series of 50 indoor patients with sputum smear-positive pulmonary tuberculosis. Place and duration of Study: Department of Medicine, Liaquat University of Medical and Health Sciences Jamshoro, Sindh, (Pakistan) from January 1999 to December 2000. Patients and methods: Four first line anti-tuberculous drugs rifampicine, ethambutol and streptomycin were tested for sensitivity pattern. Results: Twelve (26.66%) were sensitive to all four drugs, 12(26.66%) were resistant to one drug, 14 (31.11%) were resistant to two drugs, 2 (4.44%) were resistant to three drugs, and 5(11.11%) were resistant to all four drugs. Resistance to isoniazid was the most common in 27 cases (60%) with primary resistance in 6(13.33%) and secondary resistance in 21(46.66%), followed by resistance to streptomycin in 17 cases (37.77%) with primary resistance in 5(11.11%) and secondary resistance in 12 (26.66%). Resistance to ethambutol in 10 cases (22.22%) and rifampicine in 11 (24.44%) and all cases were secondary. Similarly multi-drugs resistance (MRD) TB was found in 11(24.44%) isolates. Conclusion: This study showed high prevalence of drug resistance among clinical isolates of M. tuberculosis. Their is a need to establish centers at number of places with adequate facilities for susceptibility testing so that the resistant pattern could be ascertained and treatment regimens tailored accordingly. (author)

  3. Drug-Resistant Tuberculosis: Challenges and Progress.

    Science.gov (United States)

    Kurz, Sebastian G; Furin, Jennifer J; Bark, Charles M

    2016-06-01

    Antimicrobial resistance is a natural evolutionary process, which in the case of Mycobacterium tuberculosis is based on spontaneous chromosomal mutations, meaning that well-designed combination drug regimens provided under supervised therapy will prevent the emergence of drug-resistant strains. Unfortunately, limited resources, poverty, and neglect have led to the emergence of drug-resistant tuberculosis throughout the world. The international community has responded with financial and scientific support, leading to new rapid diagnostics, new drugs and regimens in advanced clinical development, and an increasingly sophisticated understanding of resistance mechanisms and their application to all aspects of TB control and treatment. PMID:27208770

  4. Synergistic combinations of antifungals and antivirulence agents to fight against Candida albicans

    DEFF Research Database (Denmark)

    Cui, Jinhui; Ren, Biao; Tong, Yaojun;

    2015-01-01

    -drug resistance, demand innovative strategies for new effective antifungal drugs. Synergistic combinations of antifungals and anti-virulence agents highlight the pragmatic strategy to reduce the development of drug resistant and potentially repurpose known antifungals, which bypass the costly and time......Candida albicans, one of the pathogenic Candida species, causes high mortality rate in immunocompromised and high-risk surgical patients. In the last decade, only one new class of antifungal drug echinocandin was applied. The increased therapy failures, such as the one caused by multi......-consuming pipeline of new drug development. Anti-virulence and synergistic combination provide new options for antifungal drug discovery by counteracting the difficulty or failure of traditional therapy for fungal infections....

  5. Cinnamaldehyde and its derivatives, a novel class of antifungal agents.

    Science.gov (United States)

    Shreaz, Sheikh; Wani, Waseem A; Behbehani, Jawad M; Raja, Vaseem; Irshad, Md; Karched, Maribasappa; Ali, Intzar; Siddiqi, Weqar A; Hun, Lee Ting

    2016-07-01

    The last few decades have seen an alarming rise in fungal infections, which currently represent a global health threat. Despite extensive research towards the development of new antifungal agents, only a limited number of antifungal drugs are available in the market. The routinely used polyene agents and many azole antifungals are associated with some common side effects such as severe hepatotoxicity and nephrotoxicity. Also, antifungal resistance continues to grow and evolve and complicate patient management, despite the introduction of new antifungal agents. This suitation requires continuous attention. Cinnamaldehyde has been reported to inhibit bacteria, yeasts, and filamentous molds via the inhibition of ATPases, cell wall biosynthesis, and alteration of membrane structure and integrity. In this regard, several novel cinnamaldehyde derivatives were synthesized with the claim of potential antifungal activities. The present article describes antifungal properties of cinnamaldehyde and its derivatives against diverse classes of pathogenic fungi. This review will provide an overview of what is currently known about the primary mode of action of cinnamaldehyde. Synergistic approaches for boosting the effectiveness of cinnamaldehyde and its derivatives have been highlighted. Also, a keen analysis of the pharmacologically active systems derived from cinnamaldehyde has been discussed. Finally, efforts were made to outline the future perspectives of cinnamaldehyde-based antifungal agents. The purpose of this review is to provide an overview of current knowledge about the antifungal properties and antifungal mode of action of cinnamaldehyde and its derivatives and to identify research avenues that can facilitate implementation of cinnamaldehyde as a natural antifungal. PMID:27259370

  6. Lemon grass (Cymbopogon citratus essential oil as a potent anti-inflammatory and antifungal drugs

    Directory of Open Access Journals (Sweden)

    Mohamed Nadjib Boukhatem

    2014-09-01

    Full Text Available Background: Volatile oils obtained from lemon grass [Cymbopogon citratus (DC. Stapf, Poaceae family] are used in traditional medicine as remedies for the treatment of various diseases. Aims: In the present study, lemon grass essential oil (LGEO was evaluated for its in vivo topical and oral anti-inflammatory effects, and for its in vitro antifungal activity using both liquid and vapor phases. Methods: The chemical profile of LGEO as determined by gas chromatography–mass spectrometry analysis revealed two major components: geranial (42.2%, and neral (31.5%. The antifungal activity of LGEO was evaluated against several pathogenic yeasts and filamentous fungi using disc diffusion and vapor diffusion methods. Results: LGEO exhibited promising antifungal effect against Candida albicans, C. tropicalis, and Aspergillus niger, with different inhibition zone diameters (IZDs (35–90 mm. IZD increased with increasing oil volume. Significantly, higher anti-Candida activity was observed in the vapor phase. For the evaluation of the anti-inflammatory effect, LGEO (10 mg/kg, administered orally significantly reduced carrageenan-induced paw edema with a similar effect to that observed for oral diclofenac (50 mg/kg, which was used as the positive control. Oral administration of LGEO showed dose-dependent anti-inflammatory activity. In addition, topical application of LGEO in vivo resulted in a potent anti-inflammatory effect, as demonstrated by using the mouse model of croton oil-induced ear edema. To our knowledge, this is the first such report to be published. The topical application of LGEO at doses of 5 and 10 µL/ear significantly reduced acute ear edema induced by croton oil in 62.5 and 75% of the mice, respectively. In addition, histological analysis clearly confirmed that LGEO inhibits the skin inflammatory response in animal models. Conclusion: Results of the present study indicate that LGEO has a noteworthy potential for the development of drugs for

  7. Triazole derivatives with improved in vitro antifungal activity over azole drugs

    Directory of Open Access Journals (Sweden)

    Yu S

    2014-04-01

    Full Text Available Shichong Yu,1,* Xiaoyun Chai,1,* Yanwei Wang,1 Yongbing Cao,2 Jun Zhang,3 Qiuye Wu,1 Dazhi Zhang,1 Yuanying Jiang,2 Tianhua Yan,4 Qingyan Sun11Department of Organic Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, People's Republic of China; 2Drug Research Center, School of Pharmacy, Second Military Medical University, Shanghai, People's Republic of China; 3Overseas Education Faculty of the Second Military Medical University, Shanghai, People's Republic of China; 4Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, People's Republic of China*These authors contributed equally to this workAbstract: A series of triazole antifungal agents with piperidine side chains was designed and synthesized. The results of antifungal tests against eight human pathogenic fungi in vitro showed that all the compounds exhibited moderate-to-excellent activities. Molecular docking between 8d and the active site of Candida albicans CYP51 was provided based on the computational docking results. The triazole interacts with the iron of the heme group. The difluorophenyl group is located in the S3 subsite and its fluorine atom (2-F can form H-bonds with Gly307. The side chain is oriented into the S4 subsite and formed hydrophobic and van der Waals interactions with the amino residues. Moreover, the phenyl group in the side chain interacts with the phenol group of Phe380 through the formation of π–π face-to-edge interactions.Keywords: synthesis, CYP51, molecular docking, azole agents

  8. Total Protein Profile and Drug Resistance in Candida albicans Isolated from Clinical Samples

    Directory of Open Access Journals (Sweden)

    Kamal Uddin Zaidi

    2016-01-01

    Full Text Available This study was done to assess the antifungal susceptibility of clinical isolates of Candida albicans and to evaluate its total protein profile based on morphological difference on drug resistance. Hundred and twenty clinical isolates of C. albicans from various clinical specimens were tested for susceptibility against four antifungal agents, namely, fluconazole, itraconazole, amphotericin B, and ketoconazole. A significant increase of drug resistance in clinical isolates of C. albicans was observed. The study showed 50% fluconazole and itraconazole resistance at 32 μg mL−1 with a MIC50 and MIC90 values at 34 and 47 and 36 and 49 μg mL−1, respectively. All isolates were sensitive to amphotericin B and ketoconazole. The SDS-PAGE protein profile showed a prevalent band of ~52.5 kDa, indicating overexpression of gene in 72% strains with fluconazole resistance. Since the opportunistic infections of Candida spp. are increasing along with drug resistance, the total protein profile will help in understanding the evolutionary changes in drug resistance and also to characterize them.

  9. Antifungal drug susceptibility and phylogenetic diversity among Cryptococcus isolates from dogs and cats in North America.

    Science.gov (United States)

    Singer, Lisa M; Meyer, Wieland; Firacative, Carolina; Thompson, George R; Samitz, Eileen; Sykes, Jane E

    2014-06-01

    Molecular types of the Cryptococcus neoformans/Cryptococcus gattii species complex that infect dogs and cats differ regionally and with host species. Antifungal drug susceptibility can vary with molecular type, but the susceptibility of Cryptococcus isolates from dogs and cats is largely unknown. Cryptococcus isolates from 15 dogs and 27 cats were typed using URA5 restriction fragment length polymorphism analysis (RFLP), PCR fingerprinting, and multilocus sequence typing (MLST). Susceptibility was determined using a microdilution assay (Sensititre YeastOne; Trek Diagnostic Systems). MICs were compared among groups. The 42 isolates studied comprised molecular types VGI (7%), VGIIa (7%), VGIIb (5%), VGIIc (5%), VGIII (38%), VGIV (2%), VNI (33%), and VNII (2%), as determined by URA5 RFLP. The VGIV isolate was more closely related to VGIII according to MLST. All VGIII isolates were from cats. All sequence types identified from veterinary isolates clustered with isolates from humans. VGIII isolates showed considerable genetic diversity compared with other Cryptococcus molecular types and could be divided into two major subgroups. Compared with C. neoformans MICs, C. gattii MICs were lower for flucytosine, and VGIII MICs were lower for flucytosine and itraconazole. For all drugs except itraconazole, C. gattii isolates exhibited a wider range of MICs than C. neoformans. MICs varied with Cryptococcus species and molecular type in dogs and cats, and MICs of VGIII isolates were most variable and may reflect phylogenetic diversity in this group. Because sequence types of dogs and cats reflect those infecting humans, these observations may also have implications for treatment of human cryptococcosis.

  10. Overcoming drug resistance by regulating nuclear receptors

    OpenAIRE

    Chen, Taosheng

    2010-01-01

    Drug resistance involves multiple mechanisms. Multidrug resistance (MDR) is the leading cause of treatment failure in cancer therapy. Elevated levels of MDR proteins [members of the ATP-binding cassette (ABC) transporter family] increase cellular efflux and decrease the effectiveness of chemotherapeutic agents. As a salvage approach to overcome drug resistance, inhibitors of MDR proteins have been developed, but have had limited success mainly due to undesired toxicities. Nuclear receptors (N...

  11. In vitro resistance of clinical Fusarium species to amphotericin B and voriconazole using the EUCAST antifungal susceptibility method.

    Science.gov (United States)

    Taj-Aldeen, Saad J; Salah, Husam; Al-Hatmi, Abdullah M S; Hamed, Manal; Theelen, Bart; van Diepeningen, Anne D; Boekhout, Teun; Lass-Flörl, Cornelia

    2016-08-01

    Susceptibility testing using the EUCAST-AFST method against 39 clinical Fusarium strains consecutively collected from local and invasive infections during the last 10years assessed the in vitro activities of amphotericin B (AmB) and triazole antifungal agents. In addition, the susceptibility pattern of 12 reference strains from the CBS-KNAW Fungal Biodiversity Centre (CBS) was evaluated. In particular Fusarium petroliphilum and F. solani sensu lato were involved in disseminated infections and known for treatment failure. AmB displayed the lowest MICs followed by voriconazole VRC, posaconazole (POC). Itraconazole (ITC) showed high MIC values, displaying in vitro resistance. Clinical isolates were significantly (P antifungal therapy. Resistant profiles to AmB and VRC, which are the currently recommended agents in the guidelines for treatments, and a late diagnosis may be associated with high mortality rate in immunocompromised patients. The present antifungal susceptibility profiles showed that species- and strain-specific differences in antifungal susceptibility exist within Fusarium and that susceptibility testing is important and may improve the prognosis of these infections. PMID:27312690

  12. Nosocomial Candidiasis: Antifungal Stewardship and the Importance of Rapid Diagnosis.

    Science.gov (United States)

    Pfaller, Michael A; Castanheira, Mariana

    2016-01-01

    Candidemia and other forms of candidiasis are associated with considerable excess mortality and costs. Despite the addition of several new antifungal agents with improved spectrum and potency, the frequency of Candida infection and associated mortality have not decreased in the past two decades. The lack of rapid and sensitive diagnostic tests has led to considerable overuse of antifungal agents resulting in increased costs, selection pressure for resistance, unnecessary drug toxicity, and adverse drug interactions. Both the lack of timely diagnostic tests and emergence of antifungal resistance pose considerable problems for antifungal stewardship. Whereas antifungal stewardship with a focus on nosocomial candidiasis should be able to improve the administration of antifungal therapy in terms of drug selection, proper dose and duration, source control and de-escalation therapy, an important parameter, timeliness of antifungal therapy, remains a victim of slow and insensitive diagnostic tests. Fortunately, new proteomic and molecular diagnostic tools are improving the time to species identification and detection. In this review we will describe the potential impact that rapid diagnostic testing and antifungal stewardship can have on the management of nosocomial candidiasis.

  13. Identification of Aspergillus fumigatus multidrug transporter genes and their potential involvement in antifungal resistance.

    Science.gov (United States)

    Meneau, Isabelle; Coste, Alix T; Sanglard, Dominique

    2016-08-01

    Aspergillus fumigatus can cause severe fatal invasive aspergillosis in immunocompromised patients but is also found in the environment. A. fumigatus infections can be treated with antifungals agents among which azole and echinocandins. Resistance to the class of azoles has been reported not only from patient samples but also from environmental samples. Azole resistance mechanisms involve for most isolates alterations at the site of the azole target (cyp51A); however, a substantial number of isolates can also exhibit non-cyp51A-mediated mechanisms.We aimed here to identify novel A. fumigatus genes involved in azole resistance. For this purpose, we designed a functional complementation system of A. fumigatus cDNAs expressed in a Saccharomyces cerevisiae isolate lacking the ATP Binding Cassette (ABC) transporter PDR5 and that was therefore more azole-susceptible than the parent wild type. Several genes were recovered including two distinct ABC transporters (atrF, atrI) and a Major Facilitator transporter (mdrA), from which atrI (Afu3g07300) and mdrA (Afu1g13800) were not yet described. atrI mediated resistance to itraconazole and voriconazole, while atrF only to voriconazole in S. cerevisiae Gene inactivation of each transporter in A. fumigatus indicated that the transporters were involved in the basal level of azole susceptibility. The expression of the transporters was addressed in clinical and environmental isolates with several azole resistance profiles. Our results show that atrI and mdrA tended to be expressed at higher levels than atrF in normal growth conditions. atrF was upregulated in 2/4 of azole-resistant environmental isolates and was the only gene with a significant association between transporter expression and azole resistance. In conclusion, this work showed the potential of complementation to identify functional transporters. The identified transporters were suggested to participate in azole resistance of A. fumigatus; however, this hypothesis will

  14. Resistance Surveillance in Candida albicans: A Five-Year Antifungal Susceptibility Evaluation in a Brazilian University Hospital

    Science.gov (United States)

    Peron, Isabela Haddad; Reichert-Lima, Franqueline; Busso-Lopes, Ariane Fidelis; Nagasako, Cristiane Kibune; Lyra, Luzia; Moretti, Maria Luiza

    2016-01-01

    Candida albicans caused 44% of the overall candidemia episodes from 2006 to 2010 in our university tertiary care hospital. As different antifungal agents are used in therapy and also immunocompromised patients receive fluconazole prophylaxis in our institution, this study aimed to perform an antifungal susceptibility surveillance with the C.albicans bloodstream isolates and to characterize the fluconazole resistance in 2 non-blood C.albicans isolates by sequencing ERG11 gene. The study included 147 C. albicans bloodstream samples and 2 fluconazole resistant isolates: one from oral cavity (LIF 12560 fluconazole MIC: 8μg/mL) and one from esophageal cavity (LIF-E10 fluconazole MIC: 64μg/mL) of two different patients previously treated with oral fluconazole. The in vitro antifungal susceptibility to amphotericin B (AMB), 5-flucytosine (5FC), fluconazole (FLC), itraconazole (ITC), voriconazole (VRC), caspofungin (CASP) was performed by broth microdilution methodology recommended by the Clinical and Laboratory Standards Institute documents (M27-A3 and M27-S4, CLSI). All blood isolates were classified as susceptible according to CLSI guidelines for all evaluated antifungal agents (MIC range: 0,125–1.00 μg/mL for AMB, ≤0.125–1.00 μg/mL for 5FC, ≤0.125–0.5 μg/mL for FLC, ≤0.015–0.125 μg/mL for ITC, ≤0.015–0.06 μg/mL for VRC and ≤0.015–0.125 μg/mL for CASP). In this study, we also amplified and sequenced the ERG11 gene of LIF 12560 and LIF-E10 C.albicans isolates. Six mutations encoding distinct amino acid substitutions were found (E116D, T128K, E266D, A298V, G448V and G464S) and these mutations were previously described as associated with fluconazole resistance. Despite the large consumption of antifungals in our institution, resistant blood isolates were not found over the trial period. Further studies should be conducted, but it may be that the very prolonged direct contact with the oral antifungal agent administered to the patient from which

  15. Antifungal drugs as corrosion inhibitors for aluminium in 0.1 M HCl

    Energy Technology Data Exchange (ETDEWEB)

    Obot, I.B. [Department of Chemistry, Faculty of Science, University of Uyo, Uyo (Nigeria)], E-mail: proffoime@yahoo.com; Obi-Egbedi, N.O. [Department of Chemistry, University of Ibadan, Ibadan (Nigeria); Umoren, S.A. [Department of Chemistry, Faculty of Science, University of Uyo, Uyo (Nigeria)

    2009-08-15

    The inhibitive capabilities of Clotrimazole (CTM) and Fluconazole (FLC), two antifungal drugs, on the electrochemical corrosion of aluminium in 0.1 M HCl solution has been studied using weight loss measurements at 30 and 50 deg. C. The results indicate that both compound act as inhibitors in the acidic corrodent. At constant acid concentration, the inhibition efficiency (%I) increased with increase in the concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of the inhibitors but decreased the inhibition efficiency. CTM and FLC adsorbed on the surface of aluminium according to the Langmuir adsorption isotherm model at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameter obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. The reactivity of these compounds was analyzed through theoretical calculations based on AM1 semi-empirical method to explain the different efficiencies of these compounds as corrosion inhibitors. CTM was found to be a better inhibitor than FLC.

  16. Antifungal drugs as corrosion inhibitors for aluminium in 0.1 M HCl

    International Nuclear Information System (INIS)

    The inhibitive capabilities of Clotrimazole (CTM) and Fluconazole (FLC), two antifungal drugs, on the electrochemical corrosion of aluminium in 0.1 M HCl solution has been studied using weight loss measurements at 30 and 50 deg. C. The results indicate that both compound act as inhibitors in the acidic corrodent. At constant acid concentration, the inhibition efficiency (%I) increased with increase in the concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of the inhibitors but decreased the inhibition efficiency. CTM and FLC adsorbed on the surface of aluminium according to the Langmuir adsorption isotherm model at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameter obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. The reactivity of these compounds was analyzed through theoretical calculations based on AM1 semi-empirical method to explain the different efficiencies of these compounds as corrosion inhibitors. CTM was found to be a better inhibitor than FLC.

  17. Multidrug resistant to extensively drug resistant tuberculosis: What is next?

    Indian Academy of Sciences (India)

    Amita Jain; Pratima Dixit

    2008-11-01

    Drug resistant tuberculosis is a man made problem. While tuberculosis is hundred percent curable, multidrug resistant tuberculosis (MDR-TB) is difficult to treat. Inadequate and incomplete treatment and poor treatment adherence has led to a newer form of drug resistance known as extensively drug resistant tuberculosis (XDR-TB). XDR-TB is defined as tuberculosis caused by Mycobacterium tuberculosis strain, which is resistant to at least rifampicin and isoniazid among the first line anti tubercular drugs (MDR-TB) in addition to resistance to any fluroquinolones and at least one of three injectable second line anti tubercular drugs i.e. amikacin, kanamycin and/or capreomycin. Mismanagement of tuberculosis paves the way to drug resistant tuberculosis. Emergence of XDR-TB is reported world wide. Reported prevalence rates of XDR-TB of total MDR cases are; 6.6% overall worldwide, 6.5% in industrialized countries, 13.6% in Russia and Eastern Europe, 1.5% in Asia, 0.6% in Africa and Middle East and 15.4% in Republic of Korea. Better management and control of tuberculosis specially drug resistant TB by experienced and qualified doctors, access to standard microbiology laboratory, co-morbitidy of HIV and tuberculosis, new anti-TB drug regimens, better diagnostic tests, international standards for second line drugs (SLD)-susceptibility testing, invention of newer anti-tubercular molecules and vaccines and knowing the real magnitude of XDR-TB are some of the important issues to be addressed for effective prevention and management of XDR-TB.

  18. Emerging pathogens: Dynamics, mutation and drug resistance

    Energy Technology Data Exchange (ETDEWEB)

    Perelson, A.S.; Goldstein, B.; Korber, B.T. [and others

    1997-10-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objectives of this project were to develop models of the spread of pathogens, such as HIV-1 and influenza, in humans, and then to use the models to address the possibility of designing appropriate drug therapies that may limit the ability of the pathogen to escape treatment by mutating into a drug resistant form. We have developed a model of drug-resistance to amantidine and rimantadine, the two major antiviral drugs used to treat influenza, and have used the model to suggest treatment strategies during an epidemic.

  19. 武汉地区三年来抗真菌药物应用分析%Utilization Analysis of Antifungal Drugs in 3 Consecutive Years in Wuhan

    Institute of Scientific and Technical Information of China (English)

    汪震; 刘东; 杜光

    2011-01-01

    目的:了解抗真菌类药物的临床使用情况及应用趋势.方法:对长江流域药品监测网提供的武汉地区抗真菌类药物的有关数据进行汇总,分析其药品销售金额、用药频度及排序情况.结果:抗真菌类药物的销售金额逐年增长,但以进口药品注射剂的增长为主;其中氟康唑注射液的销售金额最高,而环肽类抗真菌药物的销售金额增长最快.结论:需加强国产抗真菌类药品的研发工作,以提供更有效经济的临床选择;同时,应加强抗真菌药物的利用评价工作,进一步促进药品合理使用.%Objective: To investigate the application trend of antifungal drugs in clinics. Method; The data of antifungal drugs in Wuhan provided by Hospital Purchase of Drug Information System were collected. Then the consumption sum, frequency and order of drug use were analyzed. Result; The expenditure of antifungal drugs increased year by year and the imported injections increased more quickly than the others. The expenditure of fluconazole injections was the highest among' all the antifungal drugs. The consumption sum of echinocandins increased most quickly in antifungal drugs. Conclusion: The research on the domestic antifungal drugs should be strengthened to provide more effective and economical products. And the utilization analysis of antifungal drugs should be emphasized to promote the rational use of the medicines.

  20. Facing multi-drug resistant tuberculosis.

    Science.gov (United States)

    Sotgiu, Giovanni; Migliori, Giovanni Battista

    2015-06-01

    Multi-drug resistant tuberculosis (MDR-TB) is caused by Mycobacterium tuberculosis strains resistant to at least two of the most effective anti-tuberculosis drugs (i.e., isoniazid and rifampicin). Therapeutic regimens based on second- and third-line anti-tuberculosis medicines showed poor efficacy, safety, and tolerability profiles. It was estimated that in 2012 the multi-drug resistant tuberculosis incidence ranged from 300,000 to 600,000 cases, mainly diagnosed in the Eastern European and Central Asian countries. The highest proportion of cases is among individuals previously exposed to anti-tuberculosis drugs. Three main conditions can favour the emergence and spread of multi-drug resistant tuberculosis: the poor implementation of the DOTS strategy, the shortage or the poor quality of the anti-tuberculosis drugs, and the poor therapeutic adherence of the patients to the prescribed regimens. Consultation with tuberculosis experts (e.g., consilium) is crucial to tailor the best anti-tuberculosis therapy. New therapeutic options are necessary: bedaquiline and delamanid seem promising drugs; in particular, during the development phase they demonstrated a protective effect against the emergence of further resistances towards the backbone drugs. In the recent past, other antibiotics have been administered off-label: the most relevant efficacy, safety, and tolerability profile was proved in linezolid-, meropenem/clavulanate-, cotrimoxazole-containing regimens. New research and development activities are needed in the diagnostic, therapeutic, preventive fields. PMID:24792579

  1. A database of antimalarial drug resistance

    Directory of Open Access Journals (Sweden)

    Ringwald Pascal

    2006-06-01

    Full Text Available Abstract A large investment is required to develop, license and deploy a new antimalarial drug. Too often, that investment has been rapidly devalued by the selection of parasite populations resistant to the drug action. To understand the mechanisms of selection, detailed information on the patterns of drug use in a variety of environments, and the geographic and temporal patterns of resistance is needed. Currently, there is no publically-accessible central database that contains information on the levels of resistance to antimalaria drugs. This paper outlines the resources that are available and the steps that might be taken to create a dynamic, open access database that would include current and historical data on clinical efficacy, in vitro responses and molecular markers related to drug resistance in Plasmodium falciparum and Plasmodium vivax. The goal is to include historical and current data on resistance to commonly used drugs, like chloroquine and sulfadoxine-pyrimethamine, and on the many combinations that are now being tested in different settings. The database will be accessible to all on the Web. The information in such a database will inform optimal utilization of current drugs and sustain the longest possible therapeutic life of newly introduced drugs and combinations. The database will protect the valuable investment represented by the development and deployment of novel therapies for malaria.

  2. In Vitro Screening of 10 Edible Thai Plants for Potential Antifungal Properties

    OpenAIRE

    Supattra Suwanmanee; Thitinan Kitisin; Natthanej Luplertlop

    2014-01-01

    Growing rates of fungal infections and increasing resistance against standard antifungal drugs can cause serious health problems. There is, therefore, increasing interest in the potential use of medicinal plants as novel antifungal agents. This study investigates the antifungal properties of crude plant extracts from ten medicinal plant species. Crude samples were extracted using the hot water extraction process. The minimum inhibitory concentrations (MIC) and diameter zone of inhibition were...

  3. Antimalarial drug resistance and combination chemotherapy.

    OpenAIRE

    White, N.

    1999-01-01

    Antimarial drug resistance develops when spontaneously occurring parasite mutants with reduced susceptibility are selected, and are then transmitted. Drugs for which a single point mutation confers a marked reduction in susceptibility are particularly vulnerable. Low clearance and a shallow concentration-effect relationship increase the chance of selection. Use of combinations of antimalarials that do not share the same resistance mechanisms will reduce the chance of selection because the cha...

  4. Plasmodium falciparum drug resistance in Angola

    OpenAIRE

    Fançony, Cláudia; Brito, Miguel; Gil, Jose Pedro

    2016-01-01

    Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information ...

  5. Emergence of Extensively Drug Resistant Tuberculosis

    Centers for Disease Control (CDC) Podcasts

    2007-03-01

    Extensively drug-resistant tuberculosis (XDR TB) outbreaks have been reported in South Africa, and strains have been identified on 6 continents. Dr. Peter Cegielski, team leader for drug-resistant TB with the Division of Tuberculosis Elimination at CDC, comments on a multinational team's report on this emerging global public health threat.  Created: 3/1/2007 by Emerging Infectious Diseases.   Date Released: 3/26/2007.

  6. Multidrug Transporters and Alterations in Sterol Biosynthesis Contribute to Azole Antifungal Resistance in Candida parapsilosis.

    Science.gov (United States)

    Berkow, Elizabeth L; Manigaba, Kayihura; Parker, Josie E; Barker, Katherine S; Kelly, Stephen L; Rogers, P David

    2015-10-01

    While much is known concerning azole resistance in Candida albicans, considerably less is understood about Candida parapsilosis, an emerging species of Candida with clinical relevance. We conducted a comprehensive analysis of azole resistance in a collection of resistant C. parapsilosis clinical isolates in order to determine which genes might play a role in this process within this species. We examined the relative expression of the putative drug transporter genes CDR1 and MDR1 and that of ERG11. In isolates overexpressing these genes, we sequenced the genes encoding their presumed transcriptional regulators, TAC1, MRR1, and UPC2, respectively. We also sequenced the sterol biosynthesis genes ERG3 and ERG11 in these isolates to find mutations that might contribute to this phenotype in this Candida species. Our findings demonstrate that the putative drug transporters Cdr1 and Mdr1 contribute directly to azole resistance and suggest that their overexpression is due to activating mutations in the genes encoding their transcriptional regulators. We also observed that the Y132F substitution in ERG11 is the only substitution occurring exclusively among azole-resistant isolates, and we correlated this with specific changes in sterol biosynthesis. Finally, sterol analysis of these isolates suggests that other changes in sterol biosynthesis may contribute to azole resistance in C. parapsilosis.

  7. Progress in the study of organosulfur antifungal drugs%有机硫类抗真菌药物的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘栋梁; 肖涛

    2011-01-01

    抗真菌药物(antifungal drugs)是一种用于治疗真菌感染的有效药物.近年来,天然抗真菌化合物的筛选和合成抗真菌药物的结构修饰促进了有机硫类抗真菌药物迅速发展.文中对天然有机硫类抗真菌化合物的研究进展进行了综述,同时从氮唑类、硫脲类和丙烯胺类以及硫色酮类等3类化合物的结构修饰方面综述了目前合成有机硫类抗真菌药物的研究进展.%Antifungal drugs are effective in the treatment of fungal infections. In recent years, the screening of natural antifungal compounds and structural modification of synthetic antifungal agents promote the rapid development of organosulfur antifungal drugs. The progress in the study of natural organosulfur antifungal agents and the development of the synthetic organosulfur antffungal drugs on the structural modification of azoles, thioureas and allylamines, thiochromones were reviewed.

  8. Drug resistance in Schistosomiasis: a review

    Directory of Open Access Journals (Sweden)

    John I. Bruce

    1987-01-01

    Full Text Available Drug resistance associated with the treatment of human schistosomiasis appears to be an emerging problem requiring more attention from the scientific community than the subject currently receives. Drug-resistant strains of Schistosoma mansoni have been isolated by various investigators as a result of laboratory experimentation or from a combination of field and laboratory studies. Review of this data appears to indicate that the lack of susceptibility observed for some of the isolated strains cannot be ascribed solely to previous administration of antischistosome drugs and thus further studies are required to elucidate this phenomena. Strains of S. mansoni have now been identified from Brazil which are resistant to oxamniquine, hycanthone and niridazole; from Puerto Rico which are resistant to hycanthone and oxamniquine; and from Kenya which are resistant to niridazole and probably oxamniquine. Strains derived by in vitro selection and resistant to oxamniquine and possibly to oltipraz are also available. All of these strains are currently maintained in the laboratory in snails and mice, thus providing for the first time an opportunity for indepth comparative studies. Preliminary data indicates that S. haematobium strains resistant to metrifonate may be occurring in Kenya. This problem could poise great difficulty in the eventual development of antischistosomal agents. Biomphalaria glabrata from Puerto Rico and Brazil were found to be susceptible to drug-resistant S. mansoni from each country.

  9. Drug Resistance Proteins and Refractory Epilepsy

    OpenAIRE

    J Gordon Millichap

    2002-01-01

    Expression of multi-drug resistance gene-1 P-glycoprotein (MDR1) and multidrug resistance-associated protein 1 (MRP1) in refractory epilepsy was studied at the Epilepsy Research Group, Institutes of Neurology and Child Health, University College, London, and Radcliffe Infirmary, Oxford, UK.

  10. Malaria Epidemic and Drug Resistance, Djibouti

    OpenAIRE

    Rogier, Christophe; Pradines, Bruno; Bogreau, H.; Koeck, Jean-Louis; Kamil, Mohamed-Ali; Mercereau-Puijalon, Odile

    2005-01-01

    Analysis of Plasmodium falciparum isolates collected before, during, and after a 1999 malaria epidemic in Djibouti shows that, despite a high prevalence of resistance to chloroquine, the epidemic cannot be attributed to a sudden increase in drug resistance of local parasite populations.

  11. Multiple drug resistance and bacterial infection

    Institute of Scientific and Technical Information of China (English)

    Asad U Khan

    2008-01-01

    Drug resistance is becoming a great problem in developing countries due to excessive use and misuse of antibi-otics.The emergence of new pathogenic strains with resistance developed against most of the antibiotics which may cause,difficult to treat infection.To understand the current scenario in different mode of infection is most important for the clinicians and medical practitioners.This article summarized some common infections and an-tibiotic resistance pattern found among these pathogens.

  12. Correlation between in vitro and in vivo antifungal activities in experimental fluconazole-resistant oropharyngeal and esophageal candidiasis.

    Science.gov (United States)

    Walsh, T J; Gonzalez, C E; Piscitelli, S; Bacher, J D; Peter, J; Torres, R; Shetti, D; Katsov, V; Kligys, K; Lyman, C A

    2000-06-01

    Oropharyngeal and esophageal candidiasis (OPEC) is a frequent opportunistic mycosis in immunocompromised patients. Azole-resistant OPEC is a refractory form of this infection occurring particularly in human immunodeficiency virus (HIV)-infected patients. The procedures developed by the Antifungal Subcommittee of the National Committee for Clinical Laboratory Standards (NCCLS) are an important advance in standardization of in vitro antifungal susceptibility methodology. In order to further understand the relationship between NCCLS methodology and antifungal therapeutic response, we studied the potential correlation between in vitro susceptibility to fluconazole and in vivo response in a rabbit model of fluconazole-resistant OPEC. MICs of fluconazole were determined by NCCLS methods. Three fluconazole-susceptible (FS) (MIC, /=64 microgram/ml) isolates of Candida albicans from prospectively monitored HIV-infected children with OPEC were studied. FR isolates were recovered from children with severe OPEC refractory to fluconazole, and FS isolates were recovered from those with mucosal candidiasis responsive to fluconazole. Fluconazole at 2 mg/kg of body weight/day was administered to infected animals for 7 days. The concentrations of fluconazole in plasma were maintained above the MICs for FS isolates throughout the dosing interval. Fluconazole concentrations in the esophagus were greater than or equal to those in plasma. Rabbits infected with FS isolates and treated with fluconazole had significant reductions in oral mucosal quantitative cultures (P OPEC due to C. albicans. PMID:10835005

  13. [Drug resistant epilepsy. Clinical and neurobiological concepts].

    Science.gov (United States)

    Espinosa-Jovel, Camilo A; Sobrino-Mejía, Fidel E

    2015-08-16

    Drug-resistant epilepsy, is a condition defined by the International League Against Epilepsy as persistent seizures despite having used at least two appropriate and adequate antiepileptic drug treatments. Approximately 20-30% of patients with epilepsy are going to be resistant to antiepileptic drugs, with different patterns of clinical presentation, which are related to the biological basis of this disease (de novo resistance, relapsing-remitting and progressive). Drug resistant epilepsy, impacts negatively the quality of life and significantly increases the risk of premature death. From the neurobiological point of view, this medical condition is the result of the interaction of multiple variables related to the underlying disease, drug interactions and proper genetic aspects of each patient. Thanks to advances in pharmacogenetics and molecular biology research, currently some hypotheses may explain the cause of this condition and promote the study of new therapeutic options. Currently, overexpression of membrane transporters such as P-glycoprotein, appears to be one of the most important mechanisms in the development of drug resistant epilepsy. The objective of this review is to deepen the general aspects of this clinical condition, addressing the definition, epidemiology, differential diagnosis and the pathophysiological bases.

  14. Role of drug transporters and drug accumulation in the temporal acquisition of drug resistance

    Directory of Open Access Journals (Sweden)

    Veitch Zachary

    2008-11-01

    Full Text Available Abstract Background Anthracyclines and taxanes are commonly used in the treatment of breast cancer. However, tumor resistance to these drugs often develops, possibly due to overexpression of drug transporters. It remains unclear whether drug resistance in vitro occurs at clinically relevant doses of chemotherapy drugs and whether both the onset and magnitude of drug resistance can be temporally and causally correlated with the enhanced expression and activity of specific drug transporters. To address these issues, MCF-7 cells were selected for survival in increasing concentrations of doxorubicin (MCF-7DOX-2, epirubicin (MCF-7EPI, paclitaxel (MCF-7TAX-2, or docetaxel (MCF-7TXT. During selection cells were assessed for drug sensitivity, drug uptake, and the expression of various drug transporters. Results In all cases, resistance was only achieved when selection reached a specific threshold dose, which was well within the clinical range. A reduction in drug uptake was temporally correlated with the acquisition of drug resistance for all cell lines, but further increases in drug resistance at doses above threshold were unrelated to changes in cellular drug uptake. Elevated expression of one or more drug transporters was seen at or above the threshold dose, but the identity, number, and temporal pattern of drug transporter induction varied with the drug used as selection agent. The pan drug transporter inhibitor cyclosporin A was able to partially or completely restore drug accumulation in the drug-resistant cell lines, but had only partial to no effect on drug sensitivity. The inability of cyclosporin A to restore drug sensitivity suggests the presence of additional mechanisms of drug resistance. Conclusion This study indicates that drug resistance is achieved in breast tumour cells only upon exposure to concentrations of drug at or above a specific selection dose. While changes in drug accumulation and the expression of drug transporters does

  15. Coinfection and the evolution of drug resistance.

    Science.gov (United States)

    Hansen, J; Day, T

    2014-12-01

    Recent experimental work in the rodent malaria model has shown that when two or more strains share a host, there is competitive release of drug-resistant strains upon treatment. In other words, the propagule output of a particular strain is repressed when competing with other strains and increases upon the removal of this competition. This within-host effect is predicted to have an important impact on the evolution and growth of resistant strains. However, how this effect translates to epidemiological parameters at the between-host level, the level at which disease and resistance spread, has yet to be determined. Here we present a general, between-host epidemiological model that explicitly takes into account the effect of coinfection and competitive release. Although our model does show that when there is coinfection competitive release may contribute to the emergence of resistance, it also highlights an additional between-host effect. It is the combination of these two effects, the between-host effect and the within-host effect, that determines the overall influence of coinfection on the emergence of resistance. Therefore, even when competitive release of drug-resistant strains occurs, within an infected individual, it is not necessarily true that coinfection will result in the increased emergence of resistance. These results have important implications for the control of the emergence and spread of drug resistance. PMID:25417787

  16. Antimicrobial Drugs in Fighting against Antimicrobial Resistance.

    Science.gov (United States)

    Cheng, Guyue; Dai, Menghong; Ahmed, Saeed; Hao, Haihong; Wang, Xu; Yuan, Zonghui

    2016-01-01

    The outbreak of antimicrobial resistance, together with the lack of newly developed antimicrobial drugs, represents an alarming signal for both human and animal healthcare worldwide. Selection of rational dosage regimens for traditional antimicrobial drugs based on pharmacokinetic/pharmacodynamic principles as well as development of novel antimicrobials targeting new bacterial targets or resistance mechanisms are key approaches in tackling AMR. In addition to the cellular level resistance (i.e., mutation and horizontal gene transfer of resistance determinants), the community level resistance (i.e., bilofilms and persisters) is also an issue causing antimicrobial therapy difficulties. Therefore, anti-resistance and antibiofilm strategies have currently become research hotspot to combat antimicrobial resistance. Although metallic nanoparticles can both kill bacteria and inhibit biofilm formation, the toxicity is still a big challenge for their clinical applications. In conclusion, rational use of the existing antimicrobials and combinational use of new strategies fighting against antimicrobial resistance are powerful warranties to preserve potent antimicrobial drugs for both humans and animals. PMID:27092125

  17. Antimicrobial Drugs in Fighting against Antimicrobial Resistance

    Directory of Open Access Journals (Sweden)

    Guyue eCheng

    2016-04-01

    Full Text Available The outbreak of antimicrobial resistance, together with the lack of newly developed antimicrobial drugs, represents an alarming signal for both human and animal healthcare worldwide. Selection of rational dosage regimens for traditional antimicrobial drugs based on pharmacokinetic/pharmacodynamic principles as well as development of novel antimicrobials targeting new bacterial targets or resistance mechanisms are key approaches in tackling AMR. In addition to the cellular level resistance (i.e., mutation and horizontal gene transfer of resistance determinants, the community level resistance (i.e., bilofilms and persisters is also an issue causing antimicrobial therapy difficulties. Therefore, anti-resistance and antibiofilm strategies have currently become research hotspot to combat antimicrobial resistance. Although metallic nanoparticles can both kill bacteria and inhibit biofilm formation, the toxicity is still a big challenge for their clinical applications. In conclusion, rational use of the existing antimicrobials and combinational use of new strategies fighting against antimicrobial resistance are powerful warranties to preserve potent antimicrobial drugs for both humans and animals.

  18. Defensins: antifungal lessons from eukaryotes

    Directory of Open Access Journals (Sweden)

    Patrícia M. Silva

    2014-03-01

    Full Text Available Over the last years, antimicrobial peptides (AMPs have been the focus of intense research towards the finding of a viable alternative to current antifungal drugs. Defensins are one of the major families of AMPs and the most represented among all eukaryotic groups, providing an important first line of host defense against pathogenic microorganisms. Several of these cysteine-stabilized peptides present a relevant effect against fungi. Defensins are the AMPs with the broader distribution across all eukaryotic kingdoms, namely, Fungi, Plantæ and Animalia, and were recently shown to have an ancestor in a bacterial organism. As a part of the host defense, defensins act as an important vehicle of information between innate and adaptive immune system and have a role in immunomodulation. This multidimensionality represents a powerful host shield, hard for microorganisms to overcome using single approach resistance strategies. Pathogenic fungi resistance to conventional antimycotic drugs is becoming a major problem. Defensins, as other AMPs, have shown to be an effective alternative to the current antimycotic therapies, demonstrating potential as novel therapeutic agents or drug leads. In this review, we summarize the current knowledge on some eukaryotic defensins with antifungal action. An overview of the main targets in the fungal cell and the mechanism of action of these AMPs (namely, the selectivity for some fungal membrane components are presented. Additionally, recent works on antifungal defensins structure, activity and citotoxicity are also reviewed.

  19. Epithelial-mesenchymal Transition and Tumor Drug Resistance

    Directory of Open Access Journals (Sweden)

    Linlin ZHANG

    2013-01-01

    Full Text Available Resistance to antineoplastic drugs is a common problem in cancer treatments. Epithelial-mesenchymal transition (EMT, which plays an important role in the process of drug resistance, may provide opportunity to solve this problem. This article reviews the characteristics of EMT, relationship between EMT and drug resistance, mechanism of EMT in tumor drug resistance in details.

  20. Epithelial-mesenchymal Transition and Tumor Drug Resistance

    OpenAIRE

    Zhang, Linlin; Wu, Zhihao; Zhou, Qinghua

    2013-01-01

    Resistance to antineoplastic drugs is a common problem in cancer treatments. Epithelial-mesenchymal transition (EMT), which plays an important role in the process of drug resistance, may provide opportunity to solve this problem. This article reviews the characteristics of EMT, relationship between EMT and drug resistance, mechanism of EMT in tumor drug resistance in details.

  1. Drug resistance genomics of the antimalarial drug artemisinin.

    Science.gov (United States)

    Winzeler, Elizabeth A; Manary, Micah J

    2014-01-01

    Across the globe, over 200 million annual malaria infections result in up to 660,000 deaths, 77% of which occur in children under the age of five years. Although prevention is important, malaria deaths are typically prevented by using antimalarial drugs that eliminate symptoms and clear parasites from the blood. Artemisinins are one of the few remaining compound classes that can be used to cure multidrug-resistant Plasmodium falciparum infections. Unfortunately, clinical trials from Southeast Asia are showing that artemisinin-based treatments are beginning to lose their effectiveness, adding renewed urgency to the search for the genetic determinants of parasite resistance to this important drug class. We review the genetic and genomic approaches that have led to an improved understanding of artemisinin resistance, including the identification of resistance-conferring mutations in the P. falciparum kelch13 gene. PMID:25470531

  2. Trichosporon inkin biofilms produce extracellular proteases and exhibit resistance to antifungals.

    Science.gov (United States)

    de Aguiar Cordeiro, Rossana; Serpa, Rosana; Flávia Uchoa Alexandre, Camila; de Farias Marques, Francisca Jakelyne; Vladia Silva de Melo, Charlline; da Silva Franco, Jônatas; José de Jesus Evangelista, Antonio; Pires de Camargo, Zoilo; Samia Nogueira Brilhante, Raimunda; Fabio Gadelha Rocha, Marcos; Luciano Bezerra Moreira, José; de Jesus Pinheiro Gomes Bandeira, Tereza; Júlio Costa Sidrim, José

    2015-11-01

    The aim of this study was to determine experimental conditions for in vitro biofilm formation of clinical isolates of Trichosporon inkin, an important opportunistic pathogen in immunocompromised patients. Biofilms were formed in microtitre plates in three different media (RPMI, Sabouraud and CLED), with inocula of 104, 105 or 106 cells ml- 1, at pH 5.5 and 7.0, and at 35 and 28 °C, under static and shaking conditions for 72 h. Growth kinetics of biofilms were evaluated at 6, 24, 48 and 72 h. Biofilm milieu analysis were assessed by counting viable cells and quantification of nucleic acids released into biofilm supernatants. Biofilms were also analysed for proteolytic activity and antifungal resistance against amphotericin B, caspofungin, fluconazole, itraconazole and voriconazole. Finally, ultrastructural characterization of biofilms formed in microtitre plates and catheter disks was performed by scanning electron microscopy. Greater biofilm formation was observed with a starter inoculum of 106 cells ml- 1, at pH 7.0 at 35 °C and 80 r.p.m., in both RPMI and Sabouraud media. Growth kinetics showed an increase in both viable cells and biomass with increasing incubation time, with maximum production at 48 h. Biofilms were able to disperse viable cells and nucleic acids into the supernatant throughout the developmental cycle. T. inkin biofilms produced more protease than planktonic cells and showed high tolerance to amphotericin B, caspofungin and azole derivatives. Mature biofilms were formed by different morphotypes, such as blastoconidia, arthroconidia and hyphae, in a strain-specific manner. The present article details the multicellular lifestyle of T. inkin and provides perspectives for further research.

  3. Measurement and correlation of antifungal drugs solubility in pure supercritical CO{sub 2} using semiempirical models

    Energy Technology Data Exchange (ETDEWEB)

    Yamini, Yadollah, E-mail: yyamini@modares.ac.ir [Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of); Moradi, Morteza [Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, P.O. Box 14115-175, Tehran (Iran, Islamic Republic of)

    2011-07-15

    Highlights: > Ketoconazole (KZ) and clotrimazole (CZ) are two antifungal drugs. > The solubilities of KZ and CZ were measured in supercritical CO{sub 2}. > The experimental results were correlated using five density based models. > The heats' of drug-CO{sub 2} solvation and drug vaporization were estimated. - Abstract: In the present study the solubilities of two antifungal drugs of ketoconazole and clotrimazole in supercritical carbon dioxide were measured using a simple static method. The experimental data were measured at (308 to 348) K, over the pressure range of (12.2 to 35.5) MPa. The mole fraction solubilities ranged from 0.2 . 10{sup -6} to 17.45 . 10{sup -5}. In this study five density based models were used to calculate the solubility of drugs in supercritical carbon dioxide. The density based models are Chrastil, modified Chrastil, Bartle, modified Bartle and Mendez-Santiago and Teja (M-T). Interaction parameters for the studied models were obtained and the percentage of average absolute relative deviation (AARD%) in each calculation was displayed. The correlation results showed good agreement with the experimental data. A comparison among the five models revealed that the Bartle and its modified models gave much better correlations of the solubility data with an average absolute relative deviation (AARD%) ranging from 4.8% to 6.2% and from 4.5% to 6.3% for ketoconazole and clotrimazole, respectively. Using the correlation results, the heat of drug-CO{sub 2} solvation and that of drug vaporization was separately approximated in the range of (-22.1 to -26.4 and 88.3 to 125.9) kJ . mol{sup -1}.

  4. 致病性曲霉的耐药性研究进展%The progress in antifungal resistance of pathogenic Aspergillus spp.

    Institute of Scientific and Technical Information of China (English)

    王千; 李若瑜; 刘伟

    2015-01-01

    With the wide use of antifungals in the clinic ,there have been increasing reports of resistant strains of Aspergillus spp .to antifungals .The resistance of Aspergillus spp .has important impact on the diagnosis and treatment of invasive aspergillosis .Currently ,the determination of antifungal resistance of pathogenic Aspergillus spp .relies on antifungal susceptibility testing and molecular detection .Recently ,the resistance of Aspergillus spp .to antifungals is mainly focused on azole antifungals .The research progress on antifungal resistance of pathogenic Aspergillus spp ., including the diagnosis for resistance and the molecular mechanisms ,such as over‐expression of efflux pumps ,mutations in the target enzyme (Cyp51) ,formation of biofilm and heat shock protein 90 (Hsp90)‐mediated signaling pathways are reviewed .%随着抗真菌药物在临床上的广泛使用,致病性真菌的耐药率越来越高,耐药曲霉对侵袭性曲霉病的诊治产生了重要影响。目前,致病性曲霉耐药性的确定主要依靠抗真菌药敏试验和分子诊断。在有关曲霉耐药机制的研究中,报道最多的是曲霉对唑类药物的耐药,其机制主要包括外排泵表达增加、靶酶Cyp51突变和表达水平增高、形成生物膜,以及热休克蛋白90(Hsp90)介导的信号通路参与而导致的耐药。本文就上述领域近年来的主要进展进行综述。

  5. Synthesis and investigation of novel benzimidazole derivatives as antifungal agents.

    Science.gov (United States)

    Chandrika, Nishad Thamban; Shrestha, Sanjib K; Ngo, Huy X; Garneau-Tsodikova, Sylvie

    2016-08-15

    The rise and emergence of resistance to antifungal drugs by diverse pathogenic fungal strains have resulted in an increase in demand for new antifungal agents. Various heterocyclic scaffolds with different mechanisms of action against fungi have been investigated in the past. Herein, we report the synthesis and antifungal activities of 18 alkylated mono-, bis-, and trisbenzimidazole derivatives, their toxicities against mammalian cells, as well as their ability to induce reactive oxygen species (ROS) in yeast cells. Many of our bisbenzimidazole compounds exhibited moderate to excellent antifungal activities against all tested fungal strains, with MIC values ranging from 15.6 to 0.975μg/mL. The fungal activity profiles of our bisbenzimidazoles were found to be dependent on alkyl chain length. Our most potent compounds were found to display equal or superior antifungal activity when compared to the currently used agents amphotericin B, fluconazole, itraconazole, posaconazole, and voriconazole against many of the strains tested. PMID:27301676

  6. Antifungal Resistance and Virulence Among Candida spp. from Captive Amazonian manatees and West Indian Manatees: Potential Impacts on Animal and Environmental Health.

    Science.gov (United States)

    Sidrim, José Júlio Costa; Carvalho, Vitor Luz; de Souza Collares Maia Castelo-Branco, Débora; Brilhante, Raimunda Sâmia Nogueira; de Melo Guedes, Gláucia Morgana; Barbosa, Giovanna Riello; Lazzarini, Stella Maris; Oliveira, Daniella Carvalho Ribeiro; de Meirelles, Ana Carolina Oliveira; Attademo, Fernanda Löffler Niemeyer; da Bôaviagem Freire, Augusto Carlos; de Aquino Pereira-Neto, Waldemiro; de Aguiar Cordeiro, Rossana; Moreira, José Luciano Bezerra; Rocha, Marcos Fábio Gadelha

    2016-06-01

    This work aimed at evaluating the antifungal susceptibility and production of virulence factors by Candida spp. isolated from sirenians in Brazil. The isolates (n = 105) were recovered from the natural cavities of Amazonian and West Indian manatees and were tested for the susceptibility to amphotericin B, itraconazole, and fluconazole and for the production of phospholipases, proteases, and biofilm. The minimum inhibitory concentrations (MICs) for amphotericin B ranged from 0.03 to 1 µg/mL, and no resistant isolates were detected. Itraconazole and fluconazole MICs ranged from 0.03 to 16 µg/mL and from 0.125 to 64 µg/mL, respectively, and 35.2% (37/105) of the isolates were resistant to at least one of these azole drugs. Concerning the production of virulence factors, phospholipase activity was observed in 67.6% (71/105) of the isolates, while protease activity and biofilm production were detected in 50.5% (53/105) and 32.4% (34/105) of the isolates, respectively. Since the natural cavities of manatees are colonized by resistant and virulent strains of Candida spp., these animals can act as sources of resistance and virulence genes for the environment, conspecifics and other animal species, demonstrating the potential environmental impacts associated with their release back into their natural habitat.

  7. Early State Research on Antifungal Natural Products

    OpenAIRE

    Melyssa Negri; Tânia P. Salci; Cristiane S. Shinobu-Mesquita; Isis R. G. Capoci; Terezinha I. E. Svidzinski; Erika Seki Kioshima

    2014-01-01

    Nosocomial infections caused by fungi have increased greatly in recent years, mainly due to the rising number of immunocompromised patients. However, the available antifungal therapeutic arsenal is limited, and the development of new drugs has been slow. Therefore, the search for alternative drugs with low resistance rates and fewer side effects remains a major challenge. Plants produce a variety of medicinal components that can inhibit pathogen growth. Studies of plant species have been cond...

  8. Challenges of drug-resistant malaria

    OpenAIRE

    Sinha Shweta; Medhi Bikash; Sehgal Rakesh

    2014-01-01

    Over the past six decades, the drug resistance of Plasmodium falciparum has become an issue of utmost concern. Despite the remarkable progress that has been made in recent years in reducing the mortality rate to about 30% with the scaling-up of vector control, introduction of artemisinin-based combination therapies and other malaria control strategies, the confirmation of artemisinin resistance on the Cambodia–Thailand border threatened all the previous success. This review addresses the glob...

  9. Repurposing salicylanilide anthelmintic drugs to combat drug resistant Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Rajmohan Rajamuthiah

    Full Text Available Staphylococcus aureus is a Gram-positive bacterium that has become the leading cause of hospital acquired infections in the US. Repurposing Food and Drug Administration (FDA approved drugs for antimicrobial therapy involves lower risks and costs compared to de novo development of novel antimicrobial agents. In this study, we examined the antimicrobial properties of two commercially available anthelmintic drugs. The FDA approved drug niclosamide and the veterinary drug oxyclozanide displayed strong in vivo and in vitro activity against methicillin resistant S. aureus (minimum inhibitory concentration (MIC: 0.125 and 0.5 μg/ml respectively; minimum effective concentration: ≤ 0.78 μg/ml for both drugs. The two drugs were also effective against another Gram-positive bacteria Enterococcus faecium (MIC 0.25 and 2 μg/ml respectively, but not against the Gram-negative species Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter aerogenes. The in vitro antimicrobial activity of niclosamide and oxyclozanide were determined against methicillin, vancomycin, linezolid or daptomycin resistant S. aureus clinical isolates, with MICs at 0.0625-0.5 and 0.125-2 μg/ml for niclosamide and oxyclozanide respectively. A time-kill study demonstrated that niclosamide is bacteriostatic, whereas oxyclozanide is bactericidal. Interestingly, oxyclozanide permeabilized the bacterial membrane but neither of the anthelmintic drugs exhibited demonstrable toxicity to sheep erythrocytes. Oxyclozanide was non-toxic to HepG2 human liver carcinoma cells within the range of its in vitro MICs but niclosamide displayed toxicity even at low concentrations. These data show that the salicylanilide anthelmintic drugs niclosamide and oxyclozanide are suitable candidates for mechanism of action studies and further clinical evaluation for treatment of staphylococcal infections.

  10. Synergistic effects of tacrolimus and azole antifungal compounds in fluconazole-susceptible and fluconazole-resistant Candida glabrata isolates

    Directory of Open Access Journals (Sweden)

    Laura Bedin Denardi

    2015-03-01

    Full Text Available In vitro interaction between tacrolimus (FK506 and four azoles (fluconazole, ketoconazole, itraconazole and voriconazole against thirty clinical isolates of both fluconazole susceptible and -resistant Candida glabrata were evaluated by the checkerboard microdilution method. Synergistic, indifferent or antagonism interactions were found for combinations of the antifungal agents and FK506. A larger synergistic effect was observed for the combinations of FK506 with itraconazole and voriconazole (43%, followed by that of the combination with ketoconazole (37%, against fluconazole-susceptible isolates. For fluconazole-resistant C. glabrata, a higher synergistic effect was obtained from FK506 combined with ketoconazole (77%, itraconazole (73%, voriconazole (63% and fluconazole (60%. The synergisms that we observed in vitro, notably against fluconazole-resistant C. glabrata isolates, are promising and warrant further analysis of their applications in experimental in vivo studies.

  11. [Estimation of Probiotic Lactobacilli Drug Resistance].

    Science.gov (United States)

    Bruslik, N L; Akhatova, D R; Toimentseva, A A; Abdulkhakov, S R; Ilyinskaya, O N; Yarullina, D R

    2015-01-01

    An actual problem of analysis of probiotic lactobacilli resistance to antibiotics and other drugs used in the treatment of gastro-intestinal disturbances has been for the first time solved. The levels of resistance of 19 strains of Lactobacillus (14 strains of L. fermentum, 4 strains of L.plantarum and 1 strain of L.rhamnosus) isolated from commercial probiotics and sour milk products to 14 antibiotics of various nature, i.e. β-lactams, aminoglycosides, macrolides, clindamycin, vancomycin, rifampicin, ciprofloxacin, tetracycline and chloramphenicol were determined. All the isolates were practically susceptible to the drugs of the first line antihelicobacterial therapy, i.e. amoxicillin and clarithromycin, that makes inexpedient the parallel use of the probiotics containing the above lactobacilli in the treatment of gastritis and gastric ulcer, despite the lactobacilli antagonism with respect to Helicobacter pylory. Lactobacilli are as well resistant to mesalazin and can be used for correction of dysbiosis in inflammatory affections of the intestine.

  12. [Travellers and multi-drug resistance bacteria].

    Science.gov (United States)

    Takeshita, Nozomi

    2012-02-01

    The number of international travellers has increased. There is enormous diversity in medical backgrounds, purposes of travel, and travelling styles among travellers. Travellers are hospitalized abroad because of exotic and common diseases via medical tourism. This is one way of transporting and importing human bacteria between countries, including multi-drug resistant organisms. In developing countries, the antimicrobial resistance in Shigella sp. and Salmonella sp. have been a problem, because of this trend, the first choice of antibiotics has changed in some countries. Community acquired infections as well as hospital acquired infections with MRSA, multi-drug resistance (MDR) Pseudomonas aeruginosa, and ESBL have been a problem. This review will discuss the risk of MDR bacterial infectious diseases for travellers. PMID:22413540

  13. Pathogen-induced expression of a cecropin A-melittin antimicrobial peptide gene confers antifungal resistance in transgenic tobacco.

    Science.gov (United States)

    Yevtushenko, Dmytro P; Romero, Rafael; Forward, Benjamin S; Hancock, Robert E; Kay, William W; Misra, Santosh

    2005-06-01

    Expression of defensive genes from a promoter that is specifically activated in response to pathogen invasion is highly desirable for engineering disease-resistant plants. A plant transformation vector was constructed with transcriptional fusion between the pathogen-responsive win3.12T promoter from poplar and the gene encoding the novel cecropin A-melittin hybrid peptide (CEMA) with strong antimicrobial activity. This promoter-transgene combination was evaluated in transgenic tobacco (Nicotiana tabacum L. cv. Xanthi) for enhanced plant resistance against a highly virulent pathogenic fungus Fusarium solani. Transgene expression in leaves was strongly increased after fungal infection or mechanical wounding, and the accumulation of CEMA transcripts was found to be systemic and positively correlated with the number of transgene insertions. A simple and efficient in vitro regeneration bioassay for preliminary screening of transgenic lines against pathogenic fungi was developed. CEMA had strong antifungal activity in vitro, inhibiting conidia germination at concentrations that were non-toxic to tobacco protoplasts. Most importantly, the expression level of the CEMA peptide in vivo, regulated by the win3.12T promoter, was sufficient to confer resistance against F. solani in transgenic tobacco. The antifungal resistance of plants with high CEMA expression was strong and reproducible. In addition, leaf tissue extracts from transgenic plants significantly reduced the number of fungal colonies arising from germinated conidia. Accumulation of CEMA peptide in transgenic tobacco had no deleterious effect on plant growth and development. This is the first report showing the application of a heterologous pathogen-inducible promoter to direct the expression of an antimicrobial peptide in plants, and the feasibility of this approach to provide disease resistance in tobacco and, possibly, other crops. PMID:15863447

  14. Challenges of drug-resistant malaria.

    Science.gov (United States)

    Sinha, Shweta; Medhi, Bikash; Sehgal, Rakesh

    2014-01-01

    Over the past six decades, the drug resistance of Plasmodium falciparum has become an issue of utmost concern. Despite the remarkable progress that has been made in recent years in reducing the mortality rate to about 30% with the scaling-up of vector control, introduction of artemisinin-based combination therapies and other malaria control strategies, the confirmation of artemisinin resistance on the Cambodia-Thailand border threatened all the previous success. This review addresses the global scenario of antimalarial resistance and factors associated with it, with the main emphasis on futuristic approaches like nanotechnology and stem cell therapy that may impede resistant malaria, along with novel medications which are preparing to enter the global antimalarial market. These novel studies are likely to escalate over the coming years and will hopefully help to reduce the burden of malaria. PMID:25402734

  15. Drug resistance genomics of the antimalarial drug artemisinin

    OpenAIRE

    Elizabeth A Winzeler; Manary, Micah J

    2014-01-01

    Across the globe, over 200 million annual malaria infections result in up to 660,000 deaths, 77% of which occur in children under the age of five years. Although prevention is important, malaria deaths are typically prevented by using antimalarial drugs that eliminate symptoms and clear parasites from the blood. Artemisinins are one of the few remaining compound classes that can be used to cure multidrug-resistant Plasmodium falciparum infections. Unfortunately, clinical trials from Southeast...

  16. Analysis of Pathogen Distribution and Drug Resistance of Nosocomial Infections Accompanied in Patients with Malignant Tumor

    Institute of Scientific and Technical Information of China (English)

    YAO Dong-mei; CAO Wei; QING Zhi-ju

    2008-01-01

    Objective:To investigate the pathogen distribution and drug resistance of nosocomial infections accompanied in patients with malignant tumor.Methods:The pathogen culture and drug-sensitivity data of 107 specimens isolated from malignant tumor patients accompanied with nosocomial infection were retrospectively analyzed.Results:Among 118 strains of pathogens isolated from 107 specimens,77 were gram-negative bacillus(65.3%),26 were gram-positive coccus(65.3%),and 15 were fungus(12.7%).Eleven specimens were revealed to have combined infection of bacterium and fungus.Gram-negative bacillus showed high sensitivity to amikacin,ciprofloxacin,and tienam.Gram-positive cocci were highly sensitive to tienam and vancomycin.The bacteria were resistant to other antibiotics in different degrees.Vancomycin-resistant staphylococcus was not detected.Candida was sensitive to antifungals.Conclusion:Conditional pathogenic bacteria were mainly responsible for nosocomial infections in malignant tumor patients with considerable drug resistance.This shows that bacterial tests and the rational use of antibiotics should be emphasized in clinical practice to prevent the formation of drug resistant strains and further endogenous infections.

  17. Antifungal susceptibility profiles of 1698 yeast reference strains revealing potential emerging human pathogens.

    Directory of Open Access Journals (Sweden)

    Marie Desnos-Ollivier

    Full Text Available New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes. Interestingly, geometric mean minimum inhibitory concentrations (MICs of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001. Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically "resistant" to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens.

  18. Paradoxical antifungal activity and structural observations in biofilms formed by echinocandin-resistant Candida albicans clinical isolates.

    Science.gov (United States)

    Walraven, Carla J; Bernardo, Stella M; Wiederhold, Nathan P; Lee, Samuel A

    2014-02-01

    Echinocandin-resistant clinical isolates of Candida albicans have been reported, and key-hot spot mutations in the FKS1 gene, which encodes a major glucan synthase subunit, have been identified in these (caspofungin-resistant [CAS-R]) strains. Although these mutations result in phenotypic resistance to echinocandins in planktonic cells, there is little data on antifungal susceptibilities of CAS-R C. albicans strains within biofilms. Thus, we analyzed biofilms formed by 12 C. albicans CAS-R clinical strains in which we previously identified FKS1 hot-spot mutations and compared the sessile antifungal and paradoxical activity of anidulafungin (ANID), caspofungin (CAS), and micafungin (MICA). Biofilms were formed in a 96-well static microplate model and assayed using both tetrazolium-salt reduction and crystal violet assays, as well as examination by scanning electron microscopy. We first sought to assess biofilm formation and structure in these fks1 mutants and found that the biofilm mass and metabolic activities were reduced in most of the fks1 mutants as compared with reference strain SC5314. Structural analyses revealed that the fks1 mutant biofilms were generally less dense and had a clear predominance of yeast and pseudohyphae, with unusual "pit"-like cell surface structures. We also noted that sessile minimum inhibitory concentrations (MICs) to ANID, CAS, and MICA were higher than planktonic MICs of all but one strain. The majority of strains demonstrated a paradoxical effect (PE) to particular echinocandins, in either planktonic or sessile forms. Overall, biofilms formed by echinocandin-resistant clinical isolates demonstrated varied PEs to echinocandins and were structurally characterized by a preponderance of yeast, pseudohyphae, and pit-like structures.

  19. Paradoxical antifungal activity and structural observations in biofilms formed by echinocandin-resistant Candida albicans clinical isolates.

    Science.gov (United States)

    Walraven, Carla J; Bernardo, Stella M; Wiederhold, Nathan P; Lee, Samuel A

    2014-02-01

    Echinocandin-resistant clinical isolates of Candida albicans have been reported, and key-hot spot mutations in the FKS1 gene, which encodes a major glucan synthase subunit, have been identified in these (caspofungin-resistant [CAS-R]) strains. Although these mutations result in phenotypic resistance to echinocandins in planktonic cells, there is little data on antifungal susceptibilities of CAS-R C. albicans strains within biofilms. Thus, we analyzed biofilms formed by 12 C. albicans CAS-R clinical strains in which we previously identified FKS1 hot-spot mutations and compared the sessile antifungal and paradoxical activity of anidulafungin (ANID), caspofungin (CAS), and micafungin (MICA). Biofilms were formed in a 96-well static microplate model and assayed using both tetrazolium-salt reduction and crystal violet assays, as well as examination by scanning electron microscopy. We first sought to assess biofilm formation and structure in these fks1 mutants and found that the biofilm mass and metabolic activities were reduced in most of the fks1 mutants as compared with reference strain SC5314. Structural analyses revealed that the fks1 mutant biofilms were generally less dense and had a clear predominance of yeast and pseudohyphae, with unusual "pit"-like cell surface structures. We also noted that sessile minimum inhibitory concentrations (MICs) to ANID, CAS, and MICA were higher than planktonic MICs of all but one strain. The majority of strains demonstrated a paradoxical effect (PE) to particular echinocandins, in either planktonic or sessile forms. Overall, biofilms formed by echinocandin-resistant clinical isolates demonstrated varied PEs to echinocandins and were structurally characterized by a preponderance of yeast, pseudohyphae, and pit-like structures. PMID:24576999

  20. Antifungal activity of multifunctional Fe3O4-Ag nanocolloids

    International Nuclear Information System (INIS)

    In recent years, rapid increase has been observed in the population of microbes that are resistant to conventionally used antibiotics. Antifungal drug therapy is no exception and now resistance to many of the antifungal agents in use has emerged. Therefore, there is an inevitable and urgent medical need for antibiotics with novel antimicrobial mechanisms. Aspergillus glaucus is the potential cause of fatal brain infections and hypersensitivity pneumonitis in immunocompromised patients and leads to death despite aggressive multidrug antifungal therapy. In the present article, we describe the antifungal activity of multifunctional core-shell Fe3O4-Ag nanocolloids against A. glaucus isolates. Controlled experiments are also carried out with Ag nanocolloids in order to understand the role of core (Fe3O4) in the antifungal action. The minimum inhibitory concentration (MIC) of nanocolloids is determined by the micro-dilution method. MIC of A. glaucus is 2000 μg/mL. The result is quite promising and requires further investigations in order to develop a treatment methodology against this death causing fungus in immunocompromised patients. - Research Highlights: →Synthesis of Fe3O4-Ag core-shell nanocolloids. →Antifungal activity of Fe3O4-Ag nanocolloids against Aspergillus glaucus isolates. →The MIC value for A. glaucus is 2000 μg/mL. →Antifungal activity is better or comparable with most prominent antibiotics.

  1. Multi Drug Resistant (MDR and Extensively Resistant (XDR Tuberculosis

    Directory of Open Access Journals (Sweden)

    Salih Cesur

    2013-08-01

    Full Text Available Multi drug resistant tuberculosis (MDR-TB is defined as tuberculosis that is resistant to at least isoniazid and rifampicin, the two most powerful first-line anti-TB drugs. Extensively drug resistant tuberculosis (XDR-TB is defined as tuberculosis that is resistant to resistant to isoniazid and rifampin and to any fluoroquinolone and at least one of three injectable second-line drugs (namely, amikacin, kanamicin, or capreomycin. MDR-TB and XDR- TB are great dangers that threaten the public health. XDR-TB has been reported from many countries including the United States. In Turkey, among newly diagnosed cases, it was reported that the number of MDR-TB patients was 101 (3.1%, MDR-TB rate in the retreatment cases was 17.7% (90 patients, and MDR-TB rate in all cases was 5.1 (191 patients in 2005. The percentages were calculated through the number of patients who were tested in terms of susceptibility for both isoniazide and rifampin. In 2009, it was reported that the number of MDR-TB patients was 99 (2.7% among newly diagnosed cases, it was 123 (20.5 % in the retreatment cases and the total number of MDR-TB cases was 222 (5.1%. The first patient with XDR-TB was identified in 2010 in Turkey. Diagnosis of XDR TB takes several weeks by using conventional culture-based methods, although (however some molecular test can detect it rapidly. Treatment of XDR-TB patients is difficult and usually requiring at least 18-24 months of four to six second-line anti-TB drugs. The success rate with the treatment is about 30-50%, and mortality rate is higher in HIV-infected patients. Prevention of contact to XDR-TB patients is more complicated by the lack of a proven effective preventive treatment for XDR latent tuberculosis infection. Rapid diagnostic tests and new anti-TB drugs are needed to control the spread of this worldwide public health problem. [Dis Mol Med 2013; 1(4.000: 72-76

  2. An insight into the drug resistance profile & mechanism of drug resistance in Neisseria gonorrhoeae.

    Science.gov (United States)

    Patel, Achchhe Lal; Chaudhry, Uma; Sachdev, Divya; Sachdeva, Poonam Nagpal; Bala, Manju; Saluja, Daman

    2011-10-01

    Among the aetiological agents of treatable sexually transmitted diseases (STDs), Neissseria gonorrhoeae is considered to be most important because of emerging antibiotic resistant strains that compromise the effectiveness of treatment of the disease - gonorrhoea. In most of the developing countries, treatment of gonorrhoea relies mainly on syndromic management rather than the aetiological based therapy. Gonococcal infections are usually treated with single-dose therapy with an agent found to cure > 95 per cent of cases. Unfortunately during the last few decades, N. gonorrhoeae has developed resistance not only to less expensive antimicrobials such as sulphonamides, penicillin and tetracyclines but also to fluoroquinolones. The resistance trend of N. gonorrhoeae towards these antimicrobials can be categorised into pre-quinolone, quinolone and post-quinolone era. Among the antimicrobials available so far, only the third-generation cephalosporins could be safely recommended as first-line therapy for gonorrhoea globally. However, resistance to oral third-generation cephalosporins has also started emerging in some countries. Therefore, it has become imperative to initiate sustained national and international efforts to reduce infection and misuse of antibiotics so as to prevent further emergence and spread of antimicrobial resistance. It is necessary not only to monitor drug resistance and optimise treatment regimens, but also to gain insight into how gonococcus develops drug resistance. Knowledge of mechanism of resistance would help us to devise methods to prevent the occurrence of drug resistance against existing and new drugs. Such studies could also help in finding out new drug targets in N. gonorrhoeae and also a possibility of identification of new drugs for treating gonorrhoea. PMID:22089602

  3. Antituberculosis drug resistance patterns in adults with tuberculous meningitis

    DEFF Research Database (Denmark)

    Senbayrak, Seniha; Ozkutuk, Nuri; Erdem, Hakan;

    2015-01-01

    BACKGROUND: Tuberculous meningitis (TBM) caused by Mycobacterium tuberculosis resistant to antituberculosis drugs is an increasingly common clinical problem. This study aimed to evaluate drug resistance profiles of TBM isolates in adult patients in nine European countries involving 32 centers to ...

  4. Antibacterial Cleaning Products and Drug Resistance

    OpenAIRE

    Aiello, Allison E.; Marshall, Bonnie; Levy, Stuart B.; Della-Latta, Phyllis; Lin, Susan X.; Larson, Elaine

    2005-01-01

    We examined whether household use of antibacterial cleaning and hygiene products is an emerging risk factor for carriage of antimicrobial drug–resistant bacteria on hands of household members. Households (N = 224) were randomized to use of antibacterial or nonantibacterial cleaning and hygiene products for 1 year. Logistic regression was used to assess the influence of antibacterial product use in homes. Antibacterial product use did not lead to a significant increase in antimicrobial drug re...

  5. Peptide-based Antifungal Therapies against Emerging Infections

    OpenAIRE

    Matejuk, A.; Leng, Q.; Begum, M.D.; Woodle, M.C.; Scaria, P.; Chou, S-T; Mixson, A. J.

    2010-01-01

    Acquired drug resistance to mycotic infections is rapidly emerging as a major medical problem. Opportunistic fungal infections create therapeutic challenges, particularly in high risk immunocompromised patients with AIDS, cancer, and those undergoing transplantation. Higher mortality and/or morbidity rates due to invasive mycosis have been increasing over the last 20 years, and in light of growing resistance to commonly used antibiotics, novel antifungal drugs and approaches are required. Cur...

  6. The challenge of developing robust drugs to overcome resistance

    OpenAIRE

    Anderson, Amy C; Schiffer, Celia; Pollastri, Michael; Peet, Norton P.

    2011-01-01

    Drug resistance is problematic in microbial disease, viral disease and cancer. Understanding at the outset that resistance will impact the effectiveness of any new drug that is developed for these disease categories is imperative. In this Feature, we detail approaches that have been taken with selected drug targets to reduce the susceptibility of new drugs to resistance mechanisms. We will also define the concepts of robust drugs and resilient targets, and discuss how the design of robust dru...

  7. In vitro susceptibility of antifungal drugs against Sporothrix brasiliensis recovered from cats with sporotrichosis in Brazil.

    Science.gov (United States)

    Brilhante, Raimunda Sâmia Nogueira; Rodrigues, Anderson Messias; Sidrim, José Júlio Costa; Rocha, Marcos Fábio Gadelha; Pereira, Sandro Antonio; Gremião, Isabella Dib Ferreira; Schubach, Tânia Maria Pacheco; de Camargo, Zoilo Pires

    2016-03-01

    Sporotrichosis is an important subcutaneous mycosis of humans and animals. Classically, the disease is acquired upon traumatic inoculation of Sporothrix propagules from contaminated soil and plant debris. In addition, the direct horizontal transmission of Sporothrix among animals and the resulting zoonotic infection in humans highlight an alternative and efficient rout of transmission through biting and scratching. Sporothrix brasiliensis is the most virulent species of the Sporothrix schenckii complex and is responsible for the long-lasting outbreak of feline sporotrichosis in Brazil. However, antifungal susceptibility data of animal-borne isolates is scarce. Therefore, this study evaluated the in vitro activity of amphotericin B, caspofungin, itraconazole, voriconazole, fluconazole, and ketoconazole against animal-borne isolates of S. brasiliensis. The susceptibility tests were performed through broth microdilution (M38-A2). The results show the relevant activity of itraconazole, amphotericin B, and ketoconazole against S. brasiliensis, with the following MIC ranges: 0.125-2, 0.125-4 and 0.0312-2 μg/ml, respectively. Caspofungin was moderately effective, displaying higher variation in MIC values (0.25-64 μg/ml). Voriconazole (2-64 μg/ml) and fluconazole (62.5-500 μg/ml) showed low activity against S. brasiliensis strains. This study contributed to the characterization of the in vitro antifungal susceptibility of strains of S. brasiliensis recovered from cats with sporotrichosis, which have recently been considered the main source of human infections.

  8. Antifungal activity of essential oils from Iranian plants against fluconazole-resistant and fluconazole-susceptible Candida albicans

    Directory of Open Access Journals (Sweden)

    Aghil Sharifzadeh

    2016-03-01

    Full Text Available Objectives: The purpose of this study was to assay the antifungal activity of selected essential oils obtained from plants against both fluconazole (FLU-resistant and FLU-susceptible C. albicans strains isolated from HIV positive patients with oropharyngeal candidiasis (OPC. Materials and Methods: The essential oils were obtained by hydrodistillation method from Myrtus communis (My. communis, Zingiber officinale roscoe (Z. officinale roscoe, Matricaria chamomilla (Ma. chamomilla, Trachyspermum ammi (T. ammi and Origanum vulgare (O. vulgare. The susceptibility test was based on the M27-A2 methodology. The chemical compositions of the essential oils were obtained by gas chromatography- mass spectroscopy (GC-MS. Results: In GC-MS analysis, thymol (63.40%, linalool (42%, α-pinene (27.87%, α-pinene (22.10%, and zingiberene (31.79% were found to be the major components of T. ammi, O. vulgare, My. communis, Ma. chamomilla and Z. officinale roscoe, respectively. The results showed that essential oils have different levels of antifungal activity. O. vulgare and T. ammi essential oils were found to be the most efficient (P

  9. Clotrimazole, an antifungal drug possessing diverse actions, increases the vulnerability to cadmium in lymphocytes dissociated from rat thymus

    International Nuclear Information System (INIS)

    Since clotrimazole, known as an antifungal drug, exerts diverse actions on cellular functions, it is expected that clotrimazole can be used for other purposes. This antifungal drug protects the cells overloaded with Ca2+ by A23187, a calcium ionophore. Therefore, the agent may prevent the cells from death induced by heavy metals such as CdCl2, PbCl2, or HgCl2 that are respectively proposed to increase intracellular Ca2+ concentration. To test this possibility, we have examined the effect of clotrimazole on the cells simultaneously treated with CdCl2, PbCl2, or HgCl2 using rat thymocytes and a flow cytometer with fluorescent probes. The simultaneous application of clotrimazole and CdCl2 significantly decreased cell viability, even though the concentrations of both were ineffective at affecting the viability. The significant decrease in cell viability was not due to the inhibition of Ca2+-ATPase and Ca2+-dependent K+ channels that were induced by clotrimazole. The simultaneous application increased the population of cells with phosphatidylserine exposed on membrane surface, indicating the change in asymmetrical distribution of membrane phospholipids. Furthermore, the cytotoxicity induced by the combination of clotrimazole and CdCl2 under nominally Ca2+-free condition was more profound than that under normal Ca2+ condition. Therefore, the membrane may be a target for the cytotoxic action of clotrimazole and CdCl2 that were simultaneously applied. It is also the case for PbCl2, but not the case for HgCl2. It is concluded that clotrimazole can modulate the cytotoxicity of some heavy metals

  10. HIV antiviral drug resistance: patient comprehension.

    Science.gov (United States)

    Racey, C Sarai; Zhang, Wendy; Brandson, Eirikka K; Fernandes, Kimberly A; Tzemis, Despina; Harrigan, P Richard; Montaner, Julio S G; Barrios, Rolando; Toy, Junine; Hogg, Robert S

    2010-07-01

    A patient's understanding and use of healthcare information can affect their decisions regarding treatment. Better patient understanding about HIV resistance may improve adherence to therapy, decrease population viral load and extend the use of first-line HIV therapies. We examined knowledge of developing HIV resistance and explored treatment outcomes in a cohort of HIV+ persons on highly active antiretroviral therapy (HAART). The longitudinal investigations into supportive and ancillary health services (LISA) cohort is a prospective study of HIV+ persons on HAART. A comprehensive interviewer-administrated survey collected socio-demographic variables. Drug resistance knowledge was determined using a three-part definition. Clinical markers were collected through linkage with the Drug Treatment Program (DTP) at the British Columbia Centre for Excellence in HIV/AIDS. Categorical variables were compared using Fisher's Exact Test and continuous variables using the Wilcoxon rank-sum test. Proportional odds logistic regression was performed for the adjusted multivariable analysis. Of 457 LISA participants, less than 4% completely defined HIV resistance and 20% reported that they had not discussed resistance with their physician. Overall, 61% of the cohort is >or=95% adherent based on prescription refills. Owing to small numbers pooling was preformed for analyses. The model showed that being younger (OR=0.97, 95% CI: 0.95-0.99), having greater than high school education (OR=1.64, 95% CI: 1.07-2.51), discussing medication with physicians (OR=3.67, 95% CI: 1.76-7.64), having high provider trust (OR=1.02, 95% CI: 1.01-1.03), and receiving one-to-one counseling by a pharmacist (OR=2.14, 95% CI: 1.41-3.24) are predictive of a complete or partial definition of HIV resistance. The probability of completely defining HIV resistance increased from 15.8 to 63.9% if respondents had discussed HIV medication with both a physician and a pharmacist. Although the understanding of HIV

  11. Antiproliferation of Berberine in Combination with Fluconazole from the Perspectives of Reactive Oxygen Species, Ergosterol and Drug Efflux in a Fluconazole-Resistant Candida tropicalis Isolate

    Science.gov (United States)

    Shao, Jing; Shi, GaoXiang; Wang, TianMing; Wu, DaQiang; Wang, ChangZhong

    2016-01-01

    Candida tropicalis has emerged as an important pathogenic fungus in nosocomial infections due to its recalcitrant resistance to conventional antifungal agents, especially to fluconazole (FLC). Berberine (BBR) is a bioactive herbal-originated alkaloids and has been reported to possess antifungal functions against C. albicans. In this paper, we tried to figure out the antifungal mechanisms of BBR and/or FLC in a clinical C. tropicalis isolate 2006. In the microdilution test, the minimum inhibitory concentration (MIC) of BBR was found 16 μg/mL with fractional inhibitory concentration index (FICI) 0.13 in C. tropicalis 2006. The synergism of BBR and FLC was also confirmed microscopically. After the treatments of BBR and/or FLC, the studies revealed that (i) FLC facilitated BBR to increase reactive oxygen species (ROS), (ii) FLC enhanced the intranuclear accumulation of BBR, (iii) BBR decreased the extracellular rhodamine 123 (Rh123) via inhibiting efflux transporters, (iv) FLC assisted BBR to reduce ergosterol content, and (v) BBR in combined with FLC largely downregulated the expressions of Candida drug resistance 1 (CDR1) and CDR2 but impact slightly multidrug resistance 1 (MDR1), and upregulate the expression of ergosterol 11 (ERG11). These results suggested that BBR could become a potent antifungal drug to strengthen FLC efficacy in FLC-resistant C. tropicalis via ROS increase, intracellular BBR accumulation, ergosterol decrease and efflux inhibition. PMID:27721812

  12. Candida albicans autophagy, no longer a bystander: Its role in tolerance to ER stress-related antifungal drugs.

    Science.gov (United States)

    Yu, Qilin; Jia, Chang; Dong, Yijie; Zhang, Bing; Xiao, Chenpeng; Chen, Yulu; Wang, Yuzhou; Li, Xiaoling; Wang, Lei; Zhang, Biao; Li, Mingchun

    2015-08-01

    Autophagy is a degradation process involved in pathogenicity of many pathogenic fungi. However, its roles in Candida albicans, the leading fungal pathogen in human beings, remain to be detailed. Most recently, we found that endoplasmic reticulum (ER) stress-inducing conditions led to transcriptional up-regulation of C. albicans autophagy-related (ATG) genes, implying a possible link between autophagy and ER stress response in this pathogen. Using a series of C. albicans ATG mutants and autophagy reporting systems, we found that both treatment of ER stress-related drugs and loss of the ER calcium pump Spf1 promoted autophagic flux of Atg8 and Lap41 (a homologue of Saccharomyces cerevisiae Ape1), indicating that these conditions induce autophagy. Moreover, deletion of ATG genes in the spf1Δ/Δ mutant rendered cells hypersensitive to these drugs and caused activation of UPR, revealing a role of autophagy in alleviating ER stress. In addition, only treatment of tunicamycin and loss of Spf1 in combination increased autophagic flux of the ER component Sec63, suggesting that most of the ER stress-related conditions cause non-selective autophagy rather than selective ER phagy. This study uncovers the important role of C. albicans autophagy in ER stress response and tolerance to antifungal drugs.

  13. [New developments in antifungal therapy: fluconazole, itraconazole, voriconazole, caspofungin

    NARCIS (Netherlands)

    Wout, J.W. van 't; Kuijper, E.J.; Verweij, P.E.; Kullberg, B.J.

    2004-01-01

    The azole antifungal voriconazole and the echinocandin caspofungin have recently become available for the treatment of invasive mycoses. Fluconazole remains the drug of choice for candidemia, except for infections with one of the resistent species such as Candida krusei and some strains of Candida g

  14. First case of Tritirachium oryzae as agent of onychomycosis and its susceptibility to antifungal drugs.

    Science.gov (United States)

    Naseri, Ali; Fata, Abdolmajid; Najafzadeh, Mohammad Javad

    2013-08-01

    The first case of Tritirachium oryzae isolated from an Iranian patient is reported. A 44-year-old woman with a lesion in her fingernail was examined for onychomycosis. Direct microscopic examination of the nail clippings revealed fungal filaments and inoculation of portions of the nail clippings on cultures media yielded T. oryzae after 8 days. The isolate was identified as Tritirachium spp. on the basis of gross morphological characteristics of the fungal colony and microscopic characterization of slide cultures. The diagnosis of T. oryzae was confirmed by PCR sequencing of the internal transcribed spacer domain of the rDNA gene. In vitro antifungal susceptibility test demonstrated that the fungus was susceptible to itraconazole and posaconazole. The patient was treated with oral itraconazole. PMID:23591624

  15. Sucrose ester stabilized solid lipid nanoparticles and nanostructured lipid carriers: II. Evaluation of the imidazole antifungal drug-loaded nanoparticle dispersions and their gel formulations

    Science.gov (United States)

    Das, Surajit; Kiong Ng, Wai; Tan, Reginald B. H.

    2014-03-01

    This study focused on: (i) feasibility of the previously developed sucrose ester stabilized SLNs and NLCs to encapsulate different imidazole antifungal drugs and (ii) preparation and evaluation of topical gel formulations of those SLNs and NLCs. Three imidazole antifungal drugs; clotrimazole, ketoconazole and climbazole were selected for this study. The results suggested that size, size distribution and drug encapsulation efficiency depend on the drug molecule and type of nanoparticles (SLN/NLC). The drug release experiment always showed faster drug release from NLCs than SLNs when the same drug molecule was loaded in both nanoparticles. However, drug release rate from both SLNs and NLCs followed the order of climbazole > ketoconazole > clotrimazole. NLCs demonstrated better physicochemical stability than SLNs in the case of all drugs. The drug release rate from ketoconazole- and clotrimazole-loaded SLNs became faster after three months than a fresh formulation. There was no significant change in drug release rate from climbazole-loaded SLNs and all drug-loaded NLCs. Gel formulations of SLNs and NLCs were prepared using polycarbophil polymer. Continuous flow measurements demonstrated non-Newtonian flow with shear-thinning behavior and thixotropy. Oscillation measurements depicted viscoelasticity of the gel formulations. Similar to nanoparticle dispersion, drug release rate from SLN- and NLC-gel was in the order of climbazole > ketoconazole > clotrimazole. However, significantly slower drug release was noticed from all gel formulations than their nanoparticle counterparts. Unlike nanoparticle dispersions, no significant difference in drug release from gel formulations containing SLNs and NLCs was observed for each drug. This study concludes that gel formulation of imidazole drug-loaded SLNs and NLCs can be used for sustained/prolonged topical delivery of the drugs.

  16. Sucrose ester stabilized solid lipid nanoparticles and nanostructured lipid carriers: II. Evaluation of the imidazole antifungal drug-loaded nanoparticle dispersions and their gel formulations

    International Nuclear Information System (INIS)

    This study focused on: (i) feasibility of the previously developed sucrose ester stabilized SLNs and NLCs to encapsulate different imidazole antifungal drugs and (ii) preparation and evaluation of topical gel formulations of those SLNs and NLCs. Three imidazole antifungal drugs; clotrimazole, ketoconazole and climbazole were selected for this study. The results suggested that size, size distribution and drug encapsulation efficiency depend on the drug molecule and type of nanoparticles (SLN/NLC). The drug release experiment always showed faster drug release from NLCs than SLNs when the same drug molecule was loaded in both nanoparticles. However, drug release rate from both SLNs and NLCs followed the order of climbazole > ketoconazole > clotrimazole. NLCs demonstrated better physicochemical stability than SLNs in the case of all drugs. The drug release rate from ketoconazole- and clotrimazole-loaded SLNs became faster after three months than a fresh formulation. There was no significant change in drug release rate from climbazole-loaded SLNs and all drug-loaded NLCs. Gel formulations of SLNs and NLCs were prepared using polycarbophil polymer. Continuous flow measurements demonstrated non-Newtonian flow with shear-thinning behavior and thixotropy. Oscillation measurements depicted viscoelasticity of the gel formulations. Similar to nanoparticle dispersion, drug release rate from SLN- and NLC-gel was in the order of climbazole > ketoconazole > clotrimazole. However, significantly slower drug release was noticed from all gel formulations than their nanoparticle counterparts. Unlike nanoparticle dispersions, no significant difference in drug release from gel formulations containing SLNs and NLCs was observed for each drug. This study concludes that gel formulation of imidazole drug-loaded SLNs and NLCs can be used for sustained/prolonged topical delivery of the drugs. (paper)

  17. Drug Resistant Tuberculosis — Is There Hope?

    OpenAIRE

    Manish Kumar Goel; Pardeep Khanna

    2010-01-01

    Tuberculosis remains a worldwide public healthproblem. India has the highest burden of tuberculosis inthe world and accounts for nearly 2/5th of global burdenand 2/3rd of burden in SEAR countries. The XDR- TB wasfirst described in March 2006 and has also beenreported in India. The emergence of XDR – TB isassociated with a very low probability cure and a highcase fatality as evidenced by various researchers.Extensively drug-resistant tuberculosis is rapidly fatal ifnot treated. Some studies re...

  18. Aberrant splicing and drug resistance in AML.

    Science.gov (United States)

    de Necochea-Campion, Rosalia; Shouse, Geoffrey P; Zhou, Qi; Mirshahidi, Saied; Chen, Chien-Shing

    2016-01-01

    The advent of next-generation sequencing technologies has unveiled a new window into the heterogeneity of acute myeloid leukemia (AML). In particular, recurrent mutations in spliceosome machinery and genome-wide aberrant splicing events have been recognized as a prominent component of this disease. This review will focus on how these factors influence drug resistance through altered splicing of tumor suppressor and oncogenes and dysregulation of the apoptotic signaling network. A better understanding of these factors in disease progression is necessary to design appropriate therapeutic strategies recognizing specific alternatively spliced or mutated oncogenic targets. PMID:27613060

  19. Bibliometric analysis on hepatotoxicity due to antifungal drugs%抗真菌药肝毒性的文献计量学分析

    Institute of Scientific and Technical Information of China (English)

    白艳; 李悦; 刘斌; 王昆; 梅和坤; 张颖; 王瑾; 王睿

    2014-01-01

    Objective To investigate the research progress of hepatotoxicity due to antifungal drugs, in order to provide a reference for clinical safety use of antifungal drugs. Methods "Antifungal drugs" and"hepatotoxicity" were selected as the keywords,and PubMed,Embase,Web of Science,Chinese Academic Periodical Full-text Database China HowNet Chinese Academic Journal( CNKI ) and Chinese Biomedical Literature database( CBMdisc)were searched. All literature on hepatotoxicity due to antifungal drugs were selected. A database of literature accepted for final bibliometric study was established by using Microsoft Excel. The parameters of bibliometrics such as published time( years),the top 5 countries and institutes in publishing,literature′s type,published time( years),top 5 journals in publishing number,top 10 articles in terms of cited frequency were studied. The main content and hotspot of literature were analyzed. The clinical manifestations, mechanism, incidence and prophylactico-therapeutic measures of hepatotoxicity due to antifungal drugs were summarized. Results A total of 221 articals(193 in English,28 in Chinese)were enrolled in the study,of which 116 were original articles,49 reviews and 56 case reports. The published time of first original publication of hepatotoxicity due to antifungal drugs were 1976. The journal which published largest number of articles was Mycoses. The highest citation number of individual article was 531. The main clinical manifestations were weak,right upper quadrant pain,diarrhea,jaundice,cholestasis and fever. The severe cases could cause liver failure. Laboratory examination showed elevated serum transaminases,bilirubin, and alkaline phosphatase. The incidence of liver toxicity due to azole antifungals was higher,the incidence of liver toxicity due to amphotericin B was lower. The antifungal drugs should be used with caution in patients with hypohepatia. For the patients who used antifungal drugs for long time,the liver function should

  20. 抗真菌药肝毒性的文献计量学分析%Bibliometric analysis on hepatotoxicity due to antifungal drugs

    Institute of Scientific and Technical Information of China (English)

    白艳; 李悦; 刘斌; 王昆; 梅和坤; 张颖; 王瑾; 王睿

    2014-01-01

    目的了解抗真菌药肝毒性的研究情况及其临床特征,为安全使用抗真菌药提供参考。方法以“antifungal drugs”和“hepatotoxicity”“、抗真菌药”和“肝毒性”为检索词,检索PubMed、Embase、Web of Science、中国知网中国期刊全文数据库和中国生物医学文献数据库收录的抗真菌药肝毒性文献,用Excel表对最终纳入的文献建立评价数据库,录入文献的发表年代、发文量排序前5位的国家及研究机构、文献类型、载文量前5位的期刊、被引频次前10位的文献等。分析有关文献的研究内容和热点,总结抗真菌药肝毒性的临床表现、发生机制及预防措施。结果共纳入文献221篇,其中英文文献193篇,中文文献28篇;论著116篇,综述49篇,病例报告56篇。首次发表抗真菌药肝毒性文献的时间是1976年,载文量最高的期刊是Mycoses,单篇文章的最高被引频次为531次。抗真菌药致肝损伤的临床表现为乏力、右上腹疼痛、腹泻、黄疸、胆汁淤积和发热等,严重者可致肝衰竭。实验室检查可见血清转氨酶、胆红素、碱性磷酸酶升高。唑类抗真菌药致肝损伤发生率较高,两性霉素B致肝损伤发生率较低。肝功能不全者应慎用抗真菌药。长期应用抗真菌药者应注意定期监测肝功能,出现肝损伤后立即停药并采取对症与保肝治疗,部分患者的肝功能可恢复至用药前水平。抗真菌药肝毒性的机制尚不完全清楚,可能与细胞质膜结构完整性受损或抑制细胞色素P4502D6酶代谢有关。结论国内对抗真菌药肝毒性的研究逊于国外;部分抗真菌药所致肝毒性呈可逆性。%Objective To investigate the research progress of hepatotoxicity due to antifungal drugs, in order to provide a reference for clinical safety use of antifungal drugs. Methods "Antifungal drugs" and"hepatotoxicity" were selected as the keywords

  1. Comparative study on the effects of two antifungal drugs against Candida albicans by microcalorimetry and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Qing-Lian [Zhongnan Hospital, Wuhan University, Wuhan 430071 (China); Zhang, Juan [Zhongnan Hospital, Wuhan University, Wuhan 430071 (China); Department of Stomatology, Hubei Provincial Maternal and Child Health Hospital, Wuhan 430070 (China); Xu, Zi-Qiang; Li, Ran [State Key Laboratory of Virology and Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Jiang, Feng-Lei, E-mail: fljiang@whu.edu.cn [State Key Laboratory of Virology and Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Xiao, Qi, E-mail: qi.xiao@whu.edu.cn [College of Chemistry and Life Science, Guangxi Teachers Education University, Nanning 530001 (China); Liu, Yi [State Key Laboratory of Virology and Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Microcalorimetry is a fast, simple method to study the antibiotic property of drugs. Black-Right-Pointing-Pointer We noticed that the antibiotic effect of ITZ was slightly better than that of KTZ. Black-Right-Pointing-Pointer We perform the TEM to study the morphology changes of C. albicans cells. - Abstract: In this work, a multi-channel thermal activity monitor (TAM 2277) was applied to study the growth metabolism of Candida albicans (C. albicans) in vitro in the absence and presence of different concentrations of ketoconazole (KTZ) and itraconazole (ITZ). The results showed that the half inhibiting concentrations (IC{sub 50}) of C. albicans by KTZ and ITZ are 73.5 and 66.3 {mu}mol L{sup -1}, respectively. So the antibiotic effect of ITZ was slightly better than that of KTZ. The morphology of C. albicans cells both in the absence and presence of antifungal agents was examined by transmission electron microscopy (TEM). Our research also suggests that microcalorimetry is a fast, simple, non-invasive, non-destructive and more sensitive method, and can be easily performed to study the antibiotic property of different species of drugs on microorganism compared to other biological and clinical methods.

  2. Evolutionarily repurposed networks reveal the well-known antifungal drug thiabendazole to be a novel vascular disrupting agent.

    Directory of Open Access Journals (Sweden)

    Hye Ji Cha

    Full Text Available Studies in diverse organisms have revealed a surprising depth to the evolutionary conservation of genetic modules. For example, a systematic analysis of such conserved modules has recently shown that genes in yeast that maintain cell walls have been repurposed in vertebrates to regulate vein and artery growth. We reasoned that by analyzing this particular module, we might identify small molecules targeting the yeast pathway that also act as angiogenesis inhibitors suitable for chemotherapy. This insight led to the finding that thiabendazole, an orally available antifungal drug in clinical use for 40 years, also potently inhibits angiogenesis in animal models and in human cells. Moreover, in vivo time-lapse imaging revealed that thiabendazole reversibly disassembles newly established blood vessels, marking it as vascular disrupting agent (VDA and thus as a potential complementary therapeutic for use in combination with current anti-angiogenic therapies. Importantly, we also show that thiabendazole slows tumor growth and decreases vascular density in preclinical fibrosarcoma xenografts. Thus, an exploration of the evolutionary repurposing of gene networks has led directly to the identification of a potential new therapeutic application for an inexpensive drug that is already approved for clinical use in humans.

  3. Comparative study on the effects of two antifungal drugs against Candida albicans by microcalorimetry and transmission electron microscopy

    International Nuclear Information System (INIS)

    Highlights: ► Microcalorimetry is a fast, simple method to study the antibiotic property of drugs. ► We noticed that the antibiotic effect of ITZ was slightly better than that of KTZ. ► We perform the TEM to study the morphology changes of C. albicans cells. - Abstract: In this work, a multi-channel thermal activity monitor (TAM 2277) was applied to study the growth metabolism of Candida albicans (C. albicans) in vitro in the absence and presence of different concentrations of ketoconazole (KTZ) and itraconazole (ITZ). The results showed that the half inhibiting concentrations (IC50) of C. albicans by KTZ and ITZ are 73.5 and 66.3 μmol L−1, respectively. So the antibiotic effect of ITZ was slightly better than that of KTZ. The morphology of C. albicans cells both in the absence and presence of antifungal agents was examined by transmission electron microscopy (TEM). Our research also suggests that microcalorimetry is a fast, simple, non-invasive, non-destructive and more sensitive method, and can be easily performed to study the antibiotic property of different species of drugs on microorganism compared to other biological and clinical methods.

  4. The medical and surgical treatment of drug-resistant tuberculosis

    OpenAIRE

    Calligaro, Gregory L.; Moodley, Loven; Symons, Greg; Dheda, Keertan

    2014-01-01

    Multi drug-resistant tuberculosis (MDR-TB) and extensively drug-resistant TB (XDR-TB) are burgeoning global problems with high mortality which threaten to destabilise TB control programs in several parts of the world. Of alarming concern is the emergence, in large numbers, of patients with resistance beyond XDR-TB (totally drug-resistant TB; TDR-TB or extremely drug resistant TB; XXDR-TB). Given the burgeoning global phenomenon of MDR-TB, XDR-TB and TDR-TB, and increasing international migrat...

  5. Antibody Peptide Based Antifungal Immunotherapy

    OpenAIRE

    Magliani, Walter; Conti, Stefania; Giovati, Laura; Zanello, Pier Paolo; Sperindè, Martina; Ciociola, Tecla; Polonelli, Luciano

    2012-01-01

    Fungal infections still represent relevant human illnesses worldwide and some are accompanied by unacceptably high mortality rates. The limited current availability of effective and safe antifungal agents makes the development of new drugs and approaches of antifungal vaccination/immunotherapy every day more needed. Among them, small antibody(Ab)-derived peptides are arousing great expectations as new potential antifungal agents. In this topic, the search path from the study of the yeast kill...

  6. Evaluation of Idaho's DARE "Drug Abuse Resistance Education Projects."

    Science.gov (United States)

    Silva, Roberta K.

    The goal of DARE (Drug Abuse Resistance Education) is not to completely eliminate the drug and alcohol problems of society. It is a proactive prevention program designed to equip youth (focusing on elementary school) with skills for resisting peer pressure to experiment with drugs, and to manage anger without resorting to violence or the use of…

  7. Evaluation of Idaho's DARE "Drug Abuse Resistance Education" Projects.

    Science.gov (United States)

    Silva, Roberta K.

    The DARE (Drug Abuse Resistance Education) program teaches students decision-making skills, shows them how to resist peer pressure to experiment with drugs and alcohol, and provides positive alternatives to drug use. This report looks at one state's DARE programs. Included are an overview of the implementation process, a program appraisal with…

  8. Inhibitory Potential of Antifungal Drugs on ATP-Binding Cassette Transporters P-Glycoprotein, MRP1 to MRP5, BCRP, and BSEP.

    Science.gov (United States)

    Lempers, Vincent J C; van den Heuvel, Jeroen J M W; Russel, Frans G M; Aarnoutse, Rob E; Burger, David M; Brüggemann, Roger J; Koenderink, Jan B

    2016-06-01

    Inhibition of ABC transporters is a common mechanism underlying drug-drug interactions (DDIs). We determined the inhibitory potential of antifungal drugs currently used for invasive fungal infections on ABC transporters P-glycoprotein (P-gp), MRP1 to MRP5, BCRP, and BSEP in vitro Membrane vesicles isolated from transporter-overexpressing HEK 293 cells were used to investigate the inhibitory potential of antifungal drugs (250 μM) on transport of model substrates. Concentration-inhibition curves were determined if transport inhibition was >60%. Fifty percent inhibitory concentrations (IC50s) for P-gp and BCRP were both 2 μM for itraconazole, 5 and 12 μM for hydroxyitraconazole, 3 and 6 μM for posaconazole, and 3 and 11 μM for isavuconazole, respectively. BSEP was strongly inhibited by itraconazole and hydroxyitraconazole (3 and 17 μM, respectively). Fluconazole and voriconazole did not inhibit any transport for >60%. Micafungin uniquely inhibited all transporters, with strong inhibition of MRP4 (4 μM). Anidulafungin and caspofungin showed strong inhibition of BCRP (7 and 6 μM, respectively). Amphotericin B only weakly inhibited BCRP-mediated transport (127 μM). Despite their wide range of DDIs, azole antifungals exhibit selective inhibition on efflux transporters. Although echinocandins display low potential for clinically relevant DDIs, they demonstrate potent in vitro inhibitory activity. This suggests that inhibition of ABC transporters plays a crucial role in the inexplicable (non-cytochrome P450-mediated) DDIs with antifungal drugs. PMID:27001813

  9. Bedaquiline: A novel antitubercular drug for multidrug-resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    H Nagabushan

    2014-01-01

    Full Text Available Multidrug-resistant and extensively drug-resistant tuberculosis (TB are emerging global health threats. Bedaquiline is a new antituberculous drug belonging to the diarylquinoline class that efficiently inhibits the adenosine triphosphate synthase enzyme of Mycobacterium tuberculosis. It is a bactericidal and long-acting drug. It inhibits both dormant as well as replicating bacterial sub-populations and thus shortens the duration of TB treatment. This drug has been approved by the Food and Drug Administration in December 2012 for the management of multidrug resistant-TB. The drug marks the introduction of a new addition to the TB armamentarium after four decades.

  10. Predicted levels of HIV drug resistance

    DEFF Research Database (Denmark)

    Cambiano, Valentina; Bertagnolio, Silvia; Jordan, Michael R;

    2014-01-01

    -term effects. METHODS: The previously validated HIV Synthesis model was calibrated to South Africa. Resistance was modeled at the level of single mutations, transmission potential, persistence, and effect on drug activity. RESULTS: We estimate 652 000 people (90% uncertainty range: 543 000-744 000) are living...... are maintained, in 20 years' time HIV incidence is projected to have declined by 22% (95% confidence interval, CI -23 to -21%), and the number of people carrying NNRTI resistance to be 2.9-fold higher. If enhancements in diagnosis and retention in care occur, and ART is initiated at CD4 cell count less than 500......  cells/μl, HIV incidence is projected to decline by 36% (95% CI: -37 to -36%) and the number of people with NNRTI resistance to be 4.1-fold higher than currently. Prevalence of people with viral load more than 500  copies/ml carrying NRMV is not projected to differ markedly according to future ART...

  11. Thermo-acoustical analysis of sodium dodecyl sulfate: Fluconazole (antifungal drug) based micellar system in hydro-ethanol solutions for potential drug topical application

    International Nuclear Information System (INIS)

    Highlights: • The mixed micellar system was analyzed for sodium dodecyl sulfate and fluconazole. • Early micellization was found with CMC shift towards lower surfactant concentration. • Negative ΔGmo values suggested that the micelle formation is spontaneous and feasible. • Thermo-acoustical parameters revealed the existence of intermolecular interactions within the molecules. - Abstract: Micellar systems hold excellent drug delivery applications due to their capability to solubilize a large number of hydrophobic and hydrophilic molecules. In this present work, the mixed micelle formation between the anionic surfactant sodium dodecyl sulfate (SDS) and the ‘Azole’ derivative antifungal drug fluconazole (FLZ) have been studied at four temperatures in different hydro-ethanolic solutions. The critical micelle concentration (CMC) was determined by specific conductance techniques and the experimental data was used to calculate several useful thermodynamic parameters, like standard free energy, enthalpy and entropy of micelle formation. Early micellization was found with critical micelle concentration shifting towards lower concentration (CMC) than the standard concentration of SDS in water at 25 °C suggesting that drug and the solvent system facilitates the micellization process. In addition, the transport properties were examined by employing controlled approaches likely, apparent molar volume (ϕv), apparent molar adiabatic compression (ϕk), and isentropic compression (κs) of SDS in presence of FLZ. These parameters revealed the existence of intermolecular interactions within the molecules. Therefore, this study would cast light on utilizing surfactant immobilized FLZ system for better topical biological action

  12. Study on drug resistance of mycobacterium tuberculosis in patients with pulmonary tuberculosis by drug resistance gene detecting

    International Nuclear Information System (INIS)

    To investigate drug resistance of mycobacterium tuberculosis in different age group, compare detecting effect of two methods and evaluate their the clinical application value, all of the strains of mycobacterium tuberculosis were tested for resistance to RFP, INH SM PZA and EMB by the absolute concentration method on Lowenstein-Jensen medium and the mutation of the rpoB, katG, rpsL, pncA and embB resistance genes in M. tuberculosis was tested by PCR-SSCP. In youth, middle and old age group, the rate of acquired drug resistance was 89.2%, 85.3% and 67.6% respectively, the gene mutation rate was 76.2%, 81.3% and 63.2% respectively. The rate of acquired drug resistance and multiple drug resistance in youth group was much higher than those in other groups. The gene mutation was correlated with drug resistance level of mycobacterium tuberculosis. The gene mutation rate was higher in strains isolated from high concentration resistance than those in strains isolated from low concentration resistance. The more irregular treatment was longer, the rate of drug resistance was higher. Acquired drug resistance varies in different age group. It suggested that surveillance of drug resistence in different age group should be taken seriously, especially in youth group. PCR - SSCP is a sensitive and specific method for rapid detecting rpoB, katG, rpsL, pncA and embB genes mutations of MTB. (authors)

  13. Stop the Spread of Superbugs: Help Fight Drug Resistant Bacteria

    Science.gov (United States)

    ... the Spread of Superbugs Help Fight Drug-Resistant Bacteria For nearly a century, bacteria-fighting drugs known as antibiotics have helped to control and destroy many of the harmful bacteria that can make us sick. But in recent ...

  14. Nanomedicine therapeutic approaches to overcome cancer drug resistance.

    Science.gov (United States)

    Markman, Janet L; Rekechenetskiy, Arthur; Holler, Eggehard; Ljubimova, Julia Y

    2013-11-01

    Nanomedicine is an emerging form of therapy that focuses on alternative drug delivery and improvement of the treatment efficacy while reducing detrimental side effects to normal tissues. Cancer drug resistance is a complicated process that involves multiple mechanisms. Here we discuss the major forms of drug resistance and the new possibilities that nanomedicines offer to overcome these treatment obstacles. Novel nanomedicines that have a high ability for flexible, fast drug design and production based on tumor genetic profiles can be created making drug selection for personal patient treatment much more intensive and effective. This review aims to demonstrate the advantage of the young medical science field, nanomedicine, for overcoming cancer drug resistance. With the advanced design and alternative mechanisms of drug delivery known for different nanodrugs including liposomes, polymer conjugates, micelles, dendrimers, carbon-based, and metallic nanoparticles, overcoming various forms of multi-drug resistance looks promising and opens new horizons for cancer treatment. PMID:24120656

  15. 21 CFR 333.210 - Antifungal active ingredients.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Antifungal active ingredients. 333.210 Section 333.210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Antifungal Drug Products § 333.210 Antifungal active ingredients. The active ingredient of the...

  16. PKC signaling regulates drug resistance of the fungal pathogen Candida albicans via circuitry comprised of Mkc1, calcineurin, and Hsp90.

    Directory of Open Access Journals (Sweden)

    Shantelle L LaFayette

    Full Text Available Fungal pathogens exploit diverse mechanisms to survive exposure to antifungal drugs. This poses concern given the limited number of clinically useful antifungals and the growing population of immunocompromised individuals vulnerable to life-threatening fungal infection. To identify molecules that abrogate resistance to the most widely deployed class of antifungals, the azoles, we conducted a screen of 1,280 pharmacologically active compounds. Three out of seven hits that abolished azole resistance of a resistant mutant of the model yeast Saccharomyces cerevisiae and a clinical isolate of the leading human fungal pathogen Candida albicans were inhibitors of protein kinase C (PKC, which regulates cell wall integrity during growth, morphogenesis, and response to cell wall stress. Pharmacological or genetic impairment of Pkc1 conferred hypersensitivity to multiple drugs that target synthesis of the key cell membrane sterol ergosterol, including azoles, allylamines, and morpholines. Pkc1 enabled survival of cell membrane stress at least in part via the mitogen activated protein kinase (MAPK cascade in both species, though through distinct downstream effectors. Strikingly, inhibition of Pkc1 phenocopied inhibition of the molecular chaperone Hsp90 or its client protein calcineurin. PKC signaling was required for calcineurin activation in response to drug exposure in S. cerevisiae. In contrast, Pkc1 and calcineurin independently regulate drug resistance via a common target in C. albicans. We identified an additional level of regulatory control in the C. albicans circuitry linking PKC signaling, Hsp90, and calcineurin as genetic reduction of Hsp90 led to depletion of the terminal MAPK, Mkc1. Deletion of C. albicans PKC1 rendered fungistatic ergosterol biosynthesis inhibitors fungicidal and attenuated virulence in a murine model of systemic candidiasis. This work establishes a new role for PKC signaling in drug resistance, novel circuitry through which

  17. Klebsiella pneumoniae Antimicrobial Drug Resistance, United States, 1998–2010

    OpenAIRE

    Sanchez, Guillermo V.; Master, Ronald N; Clark, Richard B.; Fyyaz, Madiha; Duvvuri, Padmaraj; Ekta, Gupta; Bordon, Jose

    2013-01-01

    We studied antimicrobial-resistant Klebsiella pneumoniae for 1998–2010 by using data from The Surveillance Network. Susceptibility results (n = 3,132,354) demonstrated significant increases in resistance to all antimicrobial drugs studied, except tetracycline. Cross-resistance among carbapenem-resistant K. pneumoniae was lower for tetracycline and amikacin.

  18. New Developments in Antiepileptic Drug Resistance: An Integrative View

    OpenAIRE

    Schmidt, Dieter; Löscher, Wolfgang

    2009-01-01

    Current theories on drug resistance in epilepsy include the drug transporter hypothesis, the drug target hypothesis, and a novel approach called the inherent severity model of epilepsy, which posits that the severity of the disease determines its relative response to medication. Valuable as each of these hypotheses is, none is currently a stand-alone theory that is able to convincingly explain drug resistance in human epilepsy. As a consequence, it may be of interest to update and integrate t...

  19. Bedaquiline: A novel antitubercular drug for multidrug-resistant tuberculosis

    OpenAIRE

    Nagabushan, H.; H. S. Roopadevi

    2014-01-01

    Multidrug-resistant and extensively drug-resistant tuberculosis (TB) are emerging global health threats. Bedaquiline is a new antituberculous drug belonging to the diarylquinoline class that efficiently inhibits the adenosine triphosphate synthase enzyme of Mycobacterium tuberculosis. It is a bactericidal and long-acting drug. It inhibits both dormant as well as replicating bacterial sub-populations and thus shortens the duration of TB treatment. This drug has been approved by the Food and Dr...

  20. From antidiabetic to antifungal: discovery of highly potent triazole-thiazolidinedione hybrids as novel antifungal agents.

    Science.gov (United States)

    Wu, Shanchao; Zhang, Yongqiang; He, Xiaomeng; Che, Xiaoying; Wang, Shengzheng; Liu, Yang; Jiang, Yan; Liu, Na; Dong, Guoqiang; Yao, Jianzhong; Miao, Zhenyuan; Wang, Yan; Zhang, Wannian; Sheng, Chunquan

    2014-12-01

    In an attempt to discover a new generation of triazole antifungal agents, a series of triazole-thiazolidinedione hybrids were designed and synthesized by molecular hybridization of the antifungal agent fluconazole and rosiglitazone (an antidiabetic). Most of the target compounds showed good to excellent inhibitory activity against a variety of clinically important fungal pathogens. In particular, compounds (Z)-5-(2,4-dichlorobenzylidene)-3-(2-(2,4-difluorophenyl)-2-hydroxy-3-(1H-1,2,4-triazol-1-yl)propyl)thiazolidine-2,4-dione) (15 c), (Z)-3-(2-(2,4-difluorophenyl)-2-hydroxy-3-(1H-1,2,4-triazol-1-yl)propyl)-5-(furan-3-ylmethylene)thiazolidine-2,4-dione (15 j), and (Z)-3-(2-(2,4-difluorophenyl)-2-hydroxy-3-(1H-1,2,4-triazol-1-yl)propyl)-5-(furan-3-ylmethylene)thiazolidine-2,4-dione (15 r) were highly active against Candida albicans, with MIC80 values in the range of 0.03-0.15 μM. Moreover, compounds 15 j and 15 r were found to be effective against four fluconazole-resistant clinical isolates; these two compounds are particularly promising antifungal leads for further optimization. Molecular docking studies revealed that the hydrogen bonding interactions between thiazolidinedione and CYP51 from C. albicans are important for antifungal activity. This study also demonstrates the effectiveness of molecular hybridization in antifungal drug discovery. PMID:25196996

  1. Public health implications of antiretroviral therapy and HIV drug resistance.

    Science.gov (United States)

    Wainberg, M A; Friedland, G

    1998-06-24

    Widespread use of antiretroviral agents and increasing occurrence of human immunodeficiency virus (HIV) strains resistant to these drugs have given rise to a number of important issues. Some of these concerns are distinct from the obvious question of the relationship between drug resistance and treatment failure and have potentially widespread public health implications. The relevant issues include but are not limited to the following: (1) frequency with which drug-resistant virus may be transmitted via sexual, intravenous, or mother-to-child routes; (2) ability of drug-resistant variants to be transmitted, a question that relates, in part, to the relative fitness of such strains; (3) effectiveness of antiviral therapy in diminishing viral burden in both blood and genital secretions, and whether this may be compromised in persons harboring resistant virus; and (4) importance of patient adherence to antiviral therapy and its relationship to sustained reduction in viral load to minimize the appearance in and transmission of drug-resistant virus from both blood and genital secretions. Thus, prevention of both development of HIV drug resistance as well as transmission of drug-resistant variants is a central issue of public health importance. Unless this topic is appropriately addressed, the likelihood is that drug-resistant variants of HIV, if able to successfully replicate, will sustain the epidemic and limit the effectiveness of antiviral therapy. PMID:9643862

  2. Emergence of non-albicans Candida species and antifungal resistance in intensive care unit patients

    Directory of Open Access Journals (Sweden)

    Ravinder Kaur

    2016-05-01

    Conclusions: Predominance of NAC species in ICU patients along with the increasing resistance being recorded to fluconazole which has a major bearing on the morbidity and management of these patients and needs to be further worked upon.

  3. In vitro antifungal activity of 2-(2'-hydroxy-5'-aminophenyl)benzoxazole in Candida spp. strains.

    Science.gov (United States)

    Daboit, Tatiane Caroline; Stopiglia, Cheila Denise Ottonelli; Carissimi, Mariana; Corbellini, Valeriano Antonio; Stefani, Valter; Scroferneker, Maria Lúcia

    2009-11-01

    The development of azole antifungals has allowed for the treatment of several fungal infections. However, the use of these compounds is restricted because of their hepatotoxicity or because they need to be administered together with other drugs in order to prevent resistance to monotherapy. Benzoxazole derivatives are among the most thriving molecular prototypes for the development of antifungal agents. 2-(2'-hydroxyphenyl) benzoxazoles are versatile molecules that emit fluorescence and have antibacterial, antiviral and antifungal properties. 2-(2'-hydroxy-5'-aminophenyl) benzoxazole (HAMBO) was tested against Candida yeast. The inhibition provided by HAMBO was lower than that of fluconazole, showing low antifungal activity against Candida spp., but equivalent to that of benzoxazoles tested in similar studies. HAMBO showed fungistatic activity against all analysed strains. This class of novel benzoxazole compounds may be used as template to produce better antifungal drugs.

  4. Antifungal susceptibility testing of yeast isolated from corneal infections

    Directory of Open Access Journals (Sweden)

    Mascaro Vera Lucia Degaspare Monte

    2003-01-01

    Full Text Available PURPOSE: To report the antifungal susceptibility profile of yeast isolates obtained from cases of keratitis. METHODS: Susceptibility testing of 15 yeast strains isolated from corneal infections to amphotericin B, fluconazole, itraconazole and ketoconazole was performed using the NCCLS broth microdilution assay. RESULTS: Most episodes of eye infections were caused by Candida albicans. The antifungal drugs tested showed the following minimal inhibitory concentration values against yeast isolates: 0.125-0.5 mg/ml for amphotericin B; 0.125->64.0 mg/ml for fluconazole; 0.015-1.0 mg/ml for itraconazole and 0.015-0.125 mg/ml for ketoconazole. Despite the fact that all Candida isolates were judged to be susceptible to azoles, one isolate showed a minimal inhibitory concentration value significantly higher than a 90% minimal inhibitory concentration of all tested isolates. Rhodotorula rubra was resistant to fluconazole and itraconazole. CONCLUSIONS: Despite the fact that most yeast isolates from corneal infections are usually susceptible to amphotericin B and azoles, they exhibit a wide range of minimal inhibitory concentration values for antifungal drugs. The identification of strains at species level and their susceptibility pattern to antifungal drugs should be considered before determining the concentration to be used in topical antifungal formulations in order to optimize therapeutic response in eye infections.

  5. Explaining risk factors for drug-resistant tuberculosis in England and Wales: contribution of primary and secondary drug resistance

    OpenAIRE

    Conaty, S. J.; Hayward, A. C.; Story, A; Glynn, J.R.; Drobniewski, F A; Watson, J.M.

    2004-01-01

    Drug-resistant tuberculosis can be transmitted (primary) or develop during the course of treatment (secondary). We investigated risk factors for each type of resistance. We compared all patients in England and Wales with isoniazid- and multidrug-resistant tuberculosis in two time-periods (1993-1994 and 1998-2000) with patients with fully sensitive tuberculosis, examining separately patients without and with previous tuberculosis (a proxy for primary and secondary drug-resistant tuberculosis)....

  6. Searching new antifungals: The use of in vitro and in vivo methods for evaluation of natural compounds.

    Science.gov (United States)

    Scorzoni, Liliana; Sangalli-Leite, Fernanda; de Lacorte Singulani, Junya; de Paula E Silva, Ana Carolina Alves; Costa-Orlandi, Caroline Barcelos; Fusco-Almeida, Ana Marisa; Mendes-Giannini, Maria José Soares

    2016-04-01

    In the last decades, the increased number of immunocompromised patients has led to the emergence of many forms of fungal infections. Furthermore, there are a restricted arsenal of antifungals available and an increase in the development of resistance to antifungal drugs. Because of these disadvantages, the search for new antifungal agents in natural sources has increased. The development of these new antifungal drugs involves various steps and methodologies. The evaluation of the in vitro antifungal activity and cytotoxicity are the first steps in the screening. There is also the possibility of antifungal combinations to improve the therapy and reduce toxicity. Despite that, the application of the new antifungal candidate could be used in association with photodynamic therapy or using nanotechnology as an ally. In vivo tests can be performed to evaluate the efficacy and toxicity using conventional and alternative animal models. In this work, we review the methods available for the evaluation of the antifungal activity and safety of natural products, as well as the recent advances of new technology in the application of natural products for antifungal therapy. PMID:26853122

  7. Antifungal therapy with an emphasis on biofilms

    OpenAIRE

    Pierce, Christopher G.; Srinivasan, Anand; Uppuluri, Priya; Anand K. Ramasubramanian; López-Ribot, José Luis

    2013-01-01

    Fungal infections are on the rise as advances in modern medicine prolong the lives of severely ill patients. Fungi are eukaryotic organisms and there are a limited number of targets for antifungal drug development; as a result the antifungal arsenal is exceedingly limited. Azoles, polyenes and echinocandins, constitute the mainstay of antifungal therapy for patients with life-threatening mycoses. One of the main factors complicating antifungal therapy is the formation of fungal biofilms, micr...

  8. Treatment of falciparum malaria in the age of drug resistance

    Directory of Open Access Journals (Sweden)

    Shanks G

    2006-01-01

    Full Text Available The growing problem of drug resistance has greatly complicated the treatment for falciparum malaria. Whereaschloroquine and sulfadoxine/pyrimethamine could once cure most infections, this is no longer true and requiresexamination of alternative regimens. Not all treatment failures are drug resistant and other issues such asexpired antimalarials and patient compliance need to be considered. Continuation of a failing treatment policyafter drug resistance is established suppresses infections rather than curing them, leading to increasedtransmission of malaria, promotion of epidemics and loss of public confidence in malaria control programs.Antifolate drug resistance (i.e. pyrimethamine means that new combinations are urgently needed particularlybecause addition of a single drug to an already failing regimen is rarely effective for very long. Atovaquone/proguanil and mefloquine have been used against multiple drug resistant falciparum malaria with resistance toeach having been documented soon after drug introduction. Drug combinations delay further transmission ofresistant parasites by increasing cure rates and inhibiting formation of gametocytes. Most currentlyrecommended drug combinations for falciparum malaria are variants of artemisinin combination therapy wherea rapidly acting artemisinin compound is combined with a longer half-life drug of a different class. Artemisininsused include dihydroartemisinin, artesunate, artemether and companion drugs include mefloquine, amodiaquine,sulfadoxine/pyrimethamine, lumefantrine, piperaquine, pyronaridine, chlorproguanil/dapsone. The standard ofcare must be to cure malaria by killing the last parasite. Combination antimalarial treatment is vital not only tothe successful treatment of individual patients but also for public health control of malaria.

  9. Study the interactions between human serum albumin and two antifungal drugs: fluconazole and its analogue DTP.

    Science.gov (United States)

    Zhang, Shao-Lin; Yao, Huankai; Wang, Chenyin; Tam, Kin Y

    2014-11-01

    Binding affinities of fluconazole and its analogue 2-(2,4-dichlorophenyl)-1,3-di(1H-1,2,4-triazol-yl)-2-propanol (DTP) to human serum albumin (HSA) were investigated under approximately human physiological conditions. The obtained result indicated that HSA could generate fluorescent quenching by fluconazole and DTP because of the formation of non-fluorescent ground-state complexes. Binding parameters calculated from the Stern-Volmer and the Scatchard equations showed that fluconazole and DTP bind to HSA with binding affinities of the order 10(4)L/mol. The thermodynamic parameters revealed that the binding was characterized by negative enthalpy and positive entropy changes, suggesting that the binding reaction was exothermic. Hydrogen bonds and hydrophobic interaction were found to be the predominant intermolecular forces stabilizing the drug-protein. The effect of metal ions on the binding constants of fluconazole-HSA complex suggested that the presence of Mg(2+) and Zn(2+) ions could decrease the free drug level and extend the half-life in the systematic circulation. Docking experiments revealed that fluconazole and DTP binds in HSA mainly by hydrophobic interaction with the possibility of hydrogen bonds formation between the drugs and the residues Arg 222, Lys 199 and Lys 195 in HSA.

  10. Adaptation and evolution of drug-resistant Mycobacterium tuberculosis

    NARCIS (Netherlands)

    I.L. Bergval

    2013-01-01

    Many studies have been conducted on drug resistance and the evolution of Mycobacterium tuberculosis. Notwithstanding, many molecular mechanisms facilitating the emergence, adaptation and spread of drug-resistant tuberculosis have yet to be discovered. This thesis reports studies of the adaptive mech

  11. Berberine Antifungal Activity in Fluconazole-Resistant Pathogenic Yeasts: Action Mechanism Evaluated by Flow Cytometry and Biofilm Growth Inhibition in Candida spp.

    Science.gov (United States)

    da Silva, Anderson Ramos; de Andrade Neto, João Batista; da Silva, Cecília Rocha; Campos, Rosana de Sousa; Costa Silva, Rose Anny; Freitas, Daniel Domingues; do Nascimento, Francisca Bruna Stefany Aires; de Andrade, Larissa Nara Dantas; Sampaio, Letícia Serpa; Grangeiro, Thalles Barbosa; Magalhães, Hemerson Iury Ferreira; Cavalcanti, Bruno Coêlho; de Moraes, Manoel Odorico; Nobre Júnior, Hélio Vitoriano

    2016-06-01

    The incidence of fungal infections and, in particular, the incidence of fungal antibiotic resistance, which is associated with biofilm formation, have significantly increased, contributing to morbidity and mortality. Thus, new therapeutic strategies need to be developed. In this context, natural products have emerged as a major source of possible antifungal agents. Berberine is a protoberberine-type isoquinoline alkaloid isolated from the roots, rhizomes, and stem bark of natural herbs, such as Berberis aquifolium, Berberis vulgaris, Berberis aristata, and Hydrastis canadensis, and of Phellodendron amurense Berberine has been proven to have broad antibacterial and antifungal activity. In the present study, the potential antifungal effect of berberine against fluconazole-resistant Candida and Cryptococcus neoformans strains, as well as against the biofilm form of Candida spp., was assessed. The antifungal effect of berberine was determined by a broth microdilution method (the M27-A3 method of the Clinical and Laboratory Standards Institute) and flow cytometry techniques, in which the probable mechanism of action of the compound was also assessed. For biofilm assessment, a colorimetric 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to determine the susceptibility of sessile cells. The isolates used in the study belonged to the Laboratory of Bioprospection and Experiments in Yeast (LABEL) of the Federal University of Ceará. After 24 and 72 h, fluconazole-resistant Candida and Cryptococcus neoformans strains showed berberine MICs equal to 8 μg/ml and 16 μg/ml, respectively. Cytometric analysis showed that treatment with berberine caused alterations to the integrity of the plasma and mitochondrial membranes and DNA damage, which led to cell death, probably by apoptosis. Assessment of biofilm-forming isolates after treatment showed statistically significant reductions in biofilm cell activity (P < 0.001). PMID:27021328

  12. Transgenic maize plants expressing the Totivirus antifungal protein, KP4, are highly resistant to corn smut

    Science.gov (United States)

    The corn smut fungus, Ustilago maydis, is a global pathogen responsible for extensive agricultural losses. Control of corn smut using traditional breeding has met with limited success because natural resistance to U. maydis is organ specific and involves numerous maize genes. Here, we present a tran...

  13. Epidemiological control of drug resistance and compensatory mutation under resistance testing and second-line therapy.

    Science.gov (United States)

    Saddler, Clare A; Wu, Yue; Valckenborgh, Frank; Tanaka, Mark M

    2013-12-01

    The fitness cost of antibiotic resistance in the absence of treatment raises the possibility that prudent use of drugs may slow or reverse the rise of resistance. Unfortunately, compensatory mutations that lower this cost may lead to entrenched resistance. Here, we develop a mathematical model of resistance evolution and compensatory mutation to determine whether reversion to sensitivity can occur, and how disease control might be facilitated by a second-line therapy. When only a single antibiotic is available, sensitive bacteria reach fixation only under treatment rates so low that hardly any cases are treated. We model a scenario in which drug sensitivity can be accurately tested so that a second-line therapy is administered to resistant cases. Before the rise of resistance to the second drug, disease eradication is possible if resistance testing and second-line treatment are conducted at a high enough rate. However, if double drug resistance arises, the possibility of disease eradication is greatly reduced and compensated resistance prevails in most of the parameter space. The boundary separating eradication from fixation of compensated resistance is strongly influenced by the underlying basic reproductive number of the pathogen and drug efficacy in sensitive cases, but depends less on the resistance cost and compensation. When double resistance is possible, the boundary is affected by the relative strengths of resistance against the two drugs in the double-resistant-compensated strain.

  14. Quantifying the Determinants of Evolutionary Dynamics Leading to Drug Resistance.

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    Guillaume Chevereau

    Full Text Available The emergence of drug resistant pathogens is a serious public health problem. It is a long-standing goal to predict rates of resistance evolution and design optimal treatment strategies accordingly. To this end, it is crucial to reveal the underlying causes of drug-specific differences in the evolutionary dynamics leading to resistance. However, it remains largely unknown why the rates of resistance evolution via spontaneous mutations and the diversity of mutational paths vary substantially between drugs. Here we comprehensively quantify the distribution of fitness effects (DFE of mutations, a key determinant of evolutionary dynamics, in the presence of eight antibiotics representing the main modes of action. Using precise high-throughput fitness measurements for genome-wide Escherichia coli gene deletion strains, we find that the width of the DFE varies dramatically between antibiotics and, contrary to conventional wisdom, for some drugs the DFE width is lower than in the absence of stress. We show that this previously underappreciated divergence in DFE width among antibiotics is largely caused by their distinct drug-specific dose-response characteristics. Unlike the DFE, the magnitude of the changes in tolerated drug concentration resulting from genome-wide mutations is similar for most drugs but exceptionally small for the antibiotic nitrofurantoin, i.e., mutations generally have considerably smaller resistance effects for nitrofurantoin than for other drugs. A population genetics model predicts that resistance evolution for drugs with this property is severely limited and confined to reproducible mutational paths. We tested this prediction in laboratory evolution experiments using the "morbidostat", a device for evolving bacteria in well-controlled drug environments. Nitrofurantoin resistance indeed evolved extremely slowly via reproducible mutations-an almost paradoxical behavior since this drug causes DNA damage and increases the mutation

  15. Overcome Cancer Cell Drug Resistance Using Natural Products

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    Pu Wang

    2015-01-01

    Full Text Available Chemotherapy is one of the major treatment methods for cancer. However, failure in chemotherapy is not uncommon, mainly due to dose-limiting toxicity associated with drug resistance. Management of drug resistance is important towards successful chemotherapy. There are many reports in the Chinese literature that natural products can overcome cancer cell drug resistance, which deserve sharing with scientific and industrial communities. We summarized the reports into four categories: (1 in vitro studies using cell line models; (2 serum pharmacology; (3 in vivo studies using animal models; and (4 clinical studies. Fourteen single compounds were reported to have antidrug resistance activity for the first time. In vitro, compounds were able to overcome drug resistance at nontoxic or subtoxic concentrations, in a dose-dependent manner, by inhibiting drug transporters, cell detoxification capacity, or cell apoptosis sensitivity. Studies in vivo showed that single compounds, herbal extract, and formulas had potent antidrug resistance activities. Importantly, many single compounds, herbal extracts, and formulas have been used clinically to treat various diseases including cancer. The review provides comprehensive data on use of natural compounds to overcome cancer cell drug resistance in China, which may facilitate the therapeutic development of natural products for clinical management of cancer drug resistance.

  16. Mycobacterium tuberculosis resistance to antituberculosis drugs in Mozambique

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    Germano Manuel Pires

    2014-04-01

    Full Text Available OBJECTIVE: To determine the drug resistance profile of Mycobacterium tuberculosis in Mozambique. METHODS: We analyzed secondary data from the National Tuberculosis Referral Laboratory, in the city of Maputo, Mozambique, and from the Beira Regional Tuberculosis Referral Laboratory, in the city of Beira, Mozambique. The data were based on culture-positive samples submitted to first-line drug susceptibility testing (DST between January and December of 2011. We attempted to determine whether the frequency of DST positivity was associated with patient type or provenance. RESULTS: During the study period, 641 strains were isolated in culture and submitted to DST. We found that 374 (58.3% were resistant to at least one antituberculosis drug and 280 (43.7% were resistant to multiple antituberculosis drugs. Of the 280 multidrug-resistant tuberculosis cases, 184 (65.7% were in previously treated patients, most of whom were from southern Mozambique. Two (0.71% of the cases of multidrug-resistant tuberculosis were confirmed to be cases of extensively drug-resistant tuberculosis. Multidrug-resistant tuberculosis was most common in males, particularly those in the 21-40 year age bracket. CONCLUSIONS: M. tuberculosis resistance to antituberculosis drugs is high in Mozambique, especially in previously treated patients. The frequency of M. tuberculosis strains that were resistant to isoniazid, rifampin, and streptomycin in combination was found to be high, particularly in samples from previously treated patients.

  17. Anti-fungal resistance in candida isolated from oral and diaper rash candidiasis in neonates

    OpenAIRE

    Mohamadi, Jasem; Motaghi, Mahsa; Panahi, Jafar; Havasian, Mohamad Reza; Delpisheh, Ali; Azizian, Mitra; PAKZAD, Iraj

    2014-01-01

    The purpose of the present study is to evaluate the sensitivity of Candida species isolated from oral candidiasis and diaper dermatitis infections in children. The children referring to private and public clinics in Ilam, Iran were exmined for oral candidiasis and diaper dermatitis. In this study, 248 oral candidiasis and diaper dermatitis samples were collected and cultured.Candida species were identified by using standard methods. Resistance and sensitivity to amphotericin B, nystatin, keto...

  18. Bedaquiline: A novel drug to combat multiple drug-resistant tuberculosis

    OpenAIRE

    Divya Goel

    2014-01-01

    Tuberculosis (TB) is among the most common infectious diseases and continues as a major global health problem. The scenario is worsened by the emergence and spread of multiple drug-resistant tuberculosis (MDR-TB) and extensive drug-resistant tuberculosis (XDR-TB). Cure rates are high for drug sensitive strains of Myobacterium tuberculosis if treatment protocols are adhered to, but treatment of MDR-TB and extensive drug drug-resistant strains is virtually impossible. The treatment of MDR-TB an...

  19. Antifungal susceptibility testing of Aspergillus species complex in the Clinical Laboratory: how to do it, when to do it, and how to interpret it

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    Esther Manso

    2014-12-01

    Full Text Available The emergence of drug resistance in fungal pathogens has a profound impact on human health given limited number of antifungal drugs. Antifungal resistance in Aspergillus spp. infection can be encountered in the antifungal drug-exposed patient due to selection of intrinsically resistant species or isolates with acquired resistance belonging to species that are normally susceptible. Resistance to triazoles is not common in Aspergillus spp., however, triazole resistance in A. fumigatus appears to be increasing in several European countries in recent years and can be clinically relevant. The Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing have developed breakpoints and epidemiological cutoff values that are now established for Aspergillus spp. Clinical microbiology laboratories will be employed commercial susceptibility assays, rather than reference broth microdilution methods and comparative studies are particularly important.

  20. Totally drug-resistant tuberculosis and adjunct therapies.

    Science.gov (United States)

    Parida, S K; Axelsson-Robertson, R; Rao, M V; Singh, N; Master, I; Lutckii, A; Keshavjee, S; Andersson, J; Zumla, A; Maeurer, M

    2015-04-01

    The first cases of totally drug-resistant (TDR) tuberculosis (TB) were reported in Italy 10 years ago; more recently, cases have also been reported in Iran, India and South Africa. Although there is no consensus on terminology, it is most commonly described as 'resistance to all first- and second-line drugs used to treat TB'. Mycobacterium tuberculosis (M.tb) acquires drug resistance mutations in a sequential fashion under suboptimal drug pressure due to monotherapy, inadequate dosing, treatment interruptions and drug interactions. The treatment of TDR-TB includes antibiotics with disputed or minimal effectiveness against M.tb, and the fatality rate is high. Comorbidities such as diabetes and infection with human immunodeficiency virus further impact on TB treatment options and survival rates. Several new drug candidates with novel modes of action are under late-stage clinical evaluation (e.g., delamanid, bedaquiline, SQ109 and sutezolid). 'Repurposed' antibiotics have also recently been included in the treatment of extensively drug resistant TB. However, because of mutations in M.tb, drugs will not provide a cure for TB in the long term. Adjunct TB therapies, including therapeutic vaccines, vitamin supplementation and/or repurposing of drugs targeting biologically and clinically relevant molecular pathways, may achieve better clinical outcomes in combination with standard chemotherapy. Here, we review broader perspectives of drug resistance in TB and potential adjunct treatment options. PMID:24809736

  1. Antimicrobial (Drug) Resistance: Methicillin-Resistant Staphylococcus aureus (MRSA)

    Science.gov (United States)

    ... Marketing Share this: Main Content Area Methicillin-Resistant Staphylococcus aureus (MRSA) During the past four decades, methicillin-resistant Staphylococcus aureus , or MRSA, has evolved from a controllable ...

  2. Drug-resistance mechanisms and prevalence of Enterobacter cloacae resistant to multi-antibiotics

    Institute of Scientific and Technical Information of China (English)

    张杰; 顾怡明; 俞云松; 周志慧; 杜小玲

    2004-01-01

    @@The main drug-resistance mechanism of gram-negative bacteria is producing β-lactamases. Two kinds of enzymes cause drug resistance by hydrolyzing oxyimino-cephalosporins and aztreonam: one is chromosomally encoded AmpC β-lactamases, the other is plasmid-mediated extended-spectrum β-lactamases (ESBLs). Enterobacter cloacae can produce both of them, so that these strains are seriously resistance to many antibiotics. In order to study the main drug-resistant mechanism in Enterobacter cloacae, PCR and nucleotide sequencing were performed on 58 multidrug resistant strains.

  3. Secondary metabolite profiles and antifungal drug susceptibility of Aspergillus fumigatus and closely related species, Aspergillus lentulus, Aspergillus udagawae, and Aspergillus viridinutans.

    Science.gov (United States)

    Tamiya, Hiroyuki; Ochiai, Eri; Kikuchi, Kazuyo; Yahiro, Maki; Toyotome, Takahito; Watanabe, Akira; Yaguchi, Takashi; Kamei, Katsuhiko

    2015-05-01

    The incidence of Aspergillus infection has been increasing in the past few years. Also, new Aspergillus fumigatus-related species, namely Aspergillus lentulus, Aspergillus udagawae, and Aspergillus viridinutans, were shown to infect humans. These fungi exhibit marked morphological similarities to A. fumigatus, albeit with different clinical courses and antifungal drug susceptibilities. The present study used liquid chromatography/time-of-flight mass spectrometry to identify the secondary metabolites secreted as virulence factors by these Aspergillus species and compared their antifungal susceptibility. The metabolite profiles varied widely among A. fumigatus, A. lentulus, A. udagawae, and A. viridinutans, producing 27, 13, 8, and 11 substances, respectively. Among the mycotoxins, fumifungin, fumiquinazoline A/B and D, fumitremorgin B, gliotoxin, sphingofungins, pseurotins, and verruculogen were only found in A. fumigatus, whereas auranthine was only found in A. lentulus. The amount of gliotoxin, one of the most abundant mycotoxins in A. fumigatus, was negligible in these related species. In addition, they had decreased susceptibility to antifungal agents such as itraconazole and voriconazole, even though metabolites that were shared in the isolates showing higher minimum inhibitory concentrations than epidemiological cutoff values were not detected. These strikingly different secondary metabolite profiles may lead to the development of more discriminative identification protocols for such closely related Aspergillus species as well as improved treatment outcomes.

  4. Fitness of Leishmania donovani parasites resistant to drug combinations.

    Directory of Open Access Journals (Sweden)

    Raquel García-Hernández

    2015-04-01

    Full Text Available Drug resistance represents one of the main problems for the use of chemotherapy to treat leishmaniasis. Additionally, it could provide some advantages to Leishmania parasites, such as a higher capacity to survive in stress conditions. In this work, in mixed populations of Leishmania donovani parasites, we have analyzed whether experimentally resistant lines to one or two combined anti-leishmanial drugs better support the stress conditions than a susceptible line expressing luciferase (Luc line. In the absence of stress, none of the Leishmania lines showed growth advantage relative to the other when mixed at a 1:1 parasite ratio. However, when promastigotes from resistant lines and the Luc line were mixed and exposed to different stresses, we observed that the resistant lines are more tolerant of different stress conditions: nutrient starvation and heat shock-pH stress. Further to this, we observed that intracellular amastigotes from resistant lines present a higher capacity to survive inside the macrophages than those of the control line. These results suggest that resistant parasites acquire an overall fitness increase and that resistance to drug combinations presents significant differences in their fitness capacity versus single-drug resistant parasites, particularly in intracellular amastigotes. These results contribute to the assessment of the possible impact of drug resistance on leishmaniasis control programs.

  5. Defeating pathogen drug resistance: guidance from evolutionary theory.

    Science.gov (United States)

    Pepper, John W

    2008-12-01

    Many of the greatest challenges in medicine and public health involve the evolution of drug resistance by pathogens. Recent advances in the theory of natural selection suggest that there are two broad classes of pathogen traits that can be targeted by drugs or vaccines. The first class, consisting of traits that benefit the individual organisms bearing them, causes a strong evolutionary response and the rapid emergence of drug resistance. The second class, consisting of traits that benefit groups of pathogen organisms including the individual provider, causes a weaker evolutionary response and less drug resistance. Although most previous drug development has targeted the first class, it would be advantageous to focus on the second class as targets for drug and vaccine development. Specific examples and test cases are discussed.

  6. Interaction of Common Azole Antifungals with P Glycoprotein

    Science.gov (United States)

    Wang, Er-jia; Lew, Karen; Casciano, Christopher N.; Clement, Robert P.; Johnson, William W.

    2002-01-01

    Both eucaryotic and procaryotic cells are resistant to a large number of antibiotics because of the activities of export transporters. The most studied transporter in the mammalian ATP-binding cassette transporter superfamily, P glycoprotein (P-gp), ejects many structurally unrelated amphiphilic and lipophilic xenobiotics. Observed clinical interactions and some in vitro studies suggest that azole antifungals may interact with P-gp. Such an interaction could both affect the disposition and exposure to azole antifungal therapeutics and partially explain the clinical drug interactions observed with some antifungals. Using a whole-cell assay in which the retention of a marker substrate is evaluated and quantified, we studied the abilities of the most widely prescribed orally administered azole antifungals to inhibit the function of this transporter. In a cell line presenting an overexpressed amount of the human P-gp transporter, itraconazole and ketoconazole inhibited P-gp function with 50% inhibitory concentrations (IC50s) of ∼2 and ∼6 μM, respectively. Cyclosporin A was inhibitory with an IC50 of 1.4 μM in this system. Uniquely, fluconazole had no effect in this assay, a result consistent with known clinical interactions. The effects of these azole antifungals on ATP consumption by P-gp (representing transport activity) were also assessed, and the Km values were congruent with the IC50s. Therefore, exposure of tissue to the azole antifungals may be modulated by human P-gp, and the clinical interactions of azole antifungals with other drugs may be due, in part, to inhibition of P-gp transport. PMID:11751127

  7. Antifungal activity of multifunctional Fe{sub 3}O{sub 4}-Ag nanocolloids

    Energy Technology Data Exchange (ETDEWEB)

    Chudasama, Bhupendra, E-mail: bnchudasama@thapar.ed [School of Physics and Materials Science, Thapar University, Patiala 147004 (India); Vala, Anjana K.; Andhariya, Nidhi [Department of Physics, Bhavnagar University, Bhavnagar 364022 (India); Upadhyay, R.V. [P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology, Changa 388421 (India); Mehta, R.V. [Department of Physics, Bhavnagar University, Bhavnagar 364022 (India)

    2011-05-15

    In recent years, rapid increase has been observed in the population of microbes that are resistant to conventionally used antibiotics. Antifungal drug therapy is no exception and now resistance to many of the antifungal agents in use has emerged. Therefore, there is an inevitable and urgent medical need for antibiotics with novel antimicrobial mechanisms. Aspergillus glaucus is the potential cause of fatal brain infections and hypersensitivity pneumonitis in immunocompromised patients and leads to death despite aggressive multidrug antifungal therapy. In the present article, we describe the antifungal activity of multifunctional core-shell Fe{sub 3}O{sub 4}-Ag nanocolloids against A. glaucus isolates. Controlled experiments are also carried out with Ag nanocolloids in order to understand the role of core (Fe{sub 3}O{sub 4}) in the antifungal action. The minimum inhibitory concentration (MIC) of nanocolloids is determined by the micro-dilution method. MIC of A. glaucus is 2000 {mu}g/mL. The result is quite promising and requires further investigations in order to develop a treatment methodology against this death causing fungus in immunocompromised patients. - Research Highlights: Synthesis of Fe{sub 3}O{sub 4}-Ag core-shell nanocolloids. Antifungal activity of Fe{sub 3}O{sub 4}-Ag nanocolloids against Aspergillus glaucus isolates. The MIC value for A. glaucus is 2000 {mu}g/mL. Antifungal activity is better or comparable with most prominent antibiotics.

  8. Delamanid: A new armor in combating drug-resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    Alphienes Stanley Xavier

    2014-01-01

    Full Text Available Intense search has been made in the discovery of newer anti-TB drugs to tackle the issues such as drug resistance, HIV co-infection and risk of drug-drug interactions in the management of TB. Delamanid, a newer mycobacterial cell wall synthesis inhibitor, received a conditional approval from European medicines agency (EMA for the treatment of MDR-TB. Preclinical and clinical studies have shown that delamanid has high potency, least risk for drug-drug interactions and better tolerability.

  9. The identification of Candida species isolated from clinical specimens of immunocompromised patients with PCR and determination of antifungal resistance genes with RFLP and sequencing analysis

    Directory of Open Access Journals (Sweden)

    Yıldız Yeğenoğlu

    2012-06-01

    Full Text Available Objectives: The aim of this study is to investigate PCRtechnique and antifungal resistance genes with RFLP andsequencing analysis in Candida species isolated fromclinical specimens of immune-compromised patients.Materials and methods: Clinical samples (96 bronchoalveolarlavages, 56 biopsy-abscess, 8 blood specimens,15 peritoneal fluid specimens, 15 pleural fluid, 5 cerebrospinalfluid and 5 pericard fluid specimens from 200 immunosuppressedpatients were studied by conventionaland molecular methods. Antifungal susceptibility testingwas performed by the E-test method. Firstly, fungal DNAwas isolated from specimens, and then the resultantproducts are defined with multiplex PCR. Antifungal resistanceand resistance genes were established by E-testand RFLP analysis.Results: Thirty of 200 samples (15% were culture positive[20 Candida albicans (67%, five Candida parapsilosis(17%, five Candida tropicalis (17%], and 170 ofsamples were found culture negative (85%. PCR with theuniversal primers detected fungal DNA in all 30 culturepositive samples. One strain was determined as resistant;2 strains were dose dependent susceptible and 27 strainswere sensitive to fluconazole by E-test. The resistancegene (ERG11 was detected by BamHI and SalI enzymesrevealed fluconazole resistance in one of C.albicansstrains. The identification was successful in Candida dubliniensis(950 bp and Candida krusei (360 bp with multiplexPCR. D132E and E216D mutations were detected insequencing of ERG 11 gene of this isolate and comparedwith reference gene in GenBank by clustal analysis.Conclusion: The molecular test methods supplies correcttherapy rather early in immunosuppressive patientstherefore it is important for the survival.

  10. Bedaquiline for the treatment of drug-resistant tuberculosis.

    Science.gov (United States)

    Bélard, Sabine; Heuvelings, Charlotte C; Janssen, Saskia; Grobusch, Martin P

    2015-05-01

    Bedaquiline is a much-needed novel drug which is highly effective against drug-resistant tuberculosis. While its clinical development has been laudably fast-tracked and the drug is now available for inclusion into treatment regimens when no suitable alternatives exist, clinical experience with bedaquiline is still limited. Phase III trial data and Phase IV studies are needed particularly to study different patient populations and to optimize treatment regimens. Drug resistance to bedaquiline needs to be monitored carefully, and full access to bedaquiline treatment where it is appropriate and needed must be promoted. PMID:25797824

  11. Drug-resistant epilepsy associated with cortical dysplasias

    Directory of Open Access Journals (Sweden)

    I. E. Poverennova

    2013-12-01

    Full Text Available Epilepsy associated with malformations of the cerebral cortex is reported in the literature to account for up to 25% of the total cases of symptomatic epilepsies. It is characterized by the most severe course and often induces drug-resistance in seizures. A group of patients with resistant seizures is singled out among the total number of patients with symptomatic epilepsy caused by cerebral cortical dysgenesis. The most important risk factors for resistance are identified in dysplasias. The prognostically unfavorable clinical features of epilepsy are described. A diagnostic algorithm is proposed to identify risk groups and to prevent drug-resistant forms of epilepsy.

  12. Monitoring of antifungal drugs in biological samples using ultrasonic-assisted supramolecular dispersive liquid-liquid microextraction based on solidification of a floating organic droplet.

    Science.gov (United States)

    Ezoddin, Maryam; Abdi, Khosrou

    2016-08-01

    A new method for the simultaneous determination of the three antifungal drugs using ultrasonic-assisted supramolecular dispersive liquid-liquid microextraction based on solidification of a floating organic droplet (UASMDLLME-SFO) was proposed. The supramolecular solvents produced from reversed micelles of 1-dodecanol (extraction solvent) in tetrahydrofuran (THF) were injected into the aqueous sample solution. Reverse micelle coacervates were produced in situ through self-assembly processes. The antifungal drugs were extracted from the aqueous sample into a supramolecular solvent. Sonication accelerated the mass transfer of the target analytes into the supramolecular solvent phase and enhanced the dispersion process. Some parameters affecting the extraction efficiency such as type and volume of the extraction solvent, pH, volume of the disperser solvent and ultrasound extraction time were investigated. Under optimum conditions, the limits of detections for ketoconazole, clotrimazole and miconazole ranged from 0.08 to 1.3μgL(-1) and the relative standard deviations (RSDs, n=5)<6% were obtained. The method was successfully applied for preconcentration of the three drugs in biological and water samples. PMID:27262083

  13. Bedaquiline: A novel drug to combat multiple drug-resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    Divya Goel

    2014-01-01

    Full Text Available Tuberculosis (TB is among the most common infectious diseases and continues as a major global health problem. The scenario is worsened by the emergence and spread of multiple drug-resistant tuberculosis (MDR-TB and extensive drug-resistant tuberculosis (XDR-TB. Cure rates are high for drug sensitive strains of Myobacterium tuberculosis if treatment protocols are adhered to, but treatment of MDR-TB and extensive drug drug-resistant strains is virtually impossible. The treatment of MDR-TB and XDR-TB relies on the drugs, which are less potent, more toxic and more costly and have to be administered for the longer duration. No new drug had come in to market for last 40 years, but the emergence of MDR-TB and XDR-TB has spurred interest in the development of novel drugs. For the effective treatment outcome, there is a dire need of new drugs with a different mechanism of action that can tackle both drug sensitive as well as drug-resistant strains. Bedaquiline is one such new drug with unique mechanism of action. Food and Drug Administration has approved bedaquiline for MDR-TB in December 2012. This article reviews the available evidence of efficacy and safety of bedaquiline.

  14. The evolution of drug-resistant malaria

    OpenAIRE

    Plowe, Christopher V.

    2008-01-01

    Molecular epidemiological investigations have uncovered the patterns of emergence and global spread of Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine. Malaria parasites highly resistant to chloroquine and pyrimethamine spread from Asian origins to Africa, at great cost to human health and life. If artemisinin-resistant falciparum malaria follows the same pattern, renewed efforts to eliminate and eradicate malaria will be gravely threatened. This paper, adapted f...

  15. Antibiotics in Animal Feed Contribute to Drug-Resistant Germs

    Science.gov (United States)

    ... medlineplus/news/fullstory_158316.html Antibiotics in Animal Feed Contribute to Drug-Resistant Germs: Study Individual farm ... HealthDay News) -- Use of antibiotics in farm animal feed is helping drive the worldwide increase in antibiotic- ...

  16. Aggressive chemotherapy and the selection of drug resistant pathogens.

    Directory of Open Access Journals (Sweden)

    Silvie Huijben

    2013-09-01

    Full Text Available Drug resistant pathogens are one of the key public health challenges of the 21st century. There is a widespread belief that resistance is best managed by using drugs to rapidly eliminate target pathogens from patients so as to minimize the probability that pathogens acquire resistance de novo. Yet strong drug pressure imposes intense selection in favor of resistance through alleviation of competition with wild-type populations. Aggressive chemotherapy thus generates opposing evolutionary forces which together determine the rate of drug resistance emergence. Identifying treatment regimens which best retard resistance evolution while maximizing health gains and minimizing disease transmission requires empirical analysis of resistance evolution in vivo in conjunction with measures of clinical outcomes and infectiousness. Using rodent malaria in laboratory mice, we found that less aggressive chemotherapeutic regimens substantially reduced the probability of onward transmission of resistance (by >150-fold, without compromising health outcomes. Our experiments suggest that there may be cases where resistance evolution can be managed more effectively with treatment regimens other than those which reduce pathogen burdens as fast as possible.

  17. Multidrug-resistant and extensively drug-resistant tuberculosis: a threat to global control of tuberculosis.

    NARCIS (Netherlands)

    Gandhi, N.R.; Nunn, P.; Dheda, K.; Schaaf, H.S.; Zignol, M.; Soolingen, D. van; Jensen, P.; Bayona, J.

    2010-01-01

    Although progress has been made to reduce global incidence of drug-susceptible tuberculosis, the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis during the past decade threatens to undermine these advances. However, countries are responding far too slowly. Of

  18. Soft X-ray tomography of phenotypic switching and the cellular response to antifungal peptoids in Candida albicans

    OpenAIRE

    Uchida, Maho; McDermott, Gerry; Wetzler, Modi; Le Gros, Mark A.; Myllys, Markko; Knoechel, Christian; Barron, Annelise E.; Larabell, Carolyn A.

    2009-01-01

    The opportunistic pathogen Candida albicans can undergo phenotypic switching between a benign, unicellular phenotype and an invasive, multicellular form that causes candidiasis. Increasingly, strains of Candida are becoming resistant to antifungal drugs, making the treatment of candidiasis difficult, especially in immunocompromised or critically ill patients. Consequently, there is a pressing need to develop new drugs that circumvent fungal drug-resistance mechanisms. In this work we used sof...

  19. Highly active ozonides selected against drug resistant malaria

    Science.gov (United States)

    Lobo, Lis; de Sousa, Bruno; Cabral, Lília; Cristiano, Maria LS; Nogueira, Fátima

    2016-01-01

    Ever increasing multi-drug resistance by Plasmodium falciparum is creating new challenges in malaria chemotherapy. In the absence of licensed vaccines, treatment and prevention of malaria is heavily dependent on drugs. Potency, range of activity, safety, low cost and ease of administration are crucial issues in the design and formulation of antimalarials. We have tested three synthetic ozonides NAC89, LC50 and LCD67 in vitro and in vivo against multidrug resistant Plasmodium. In vitro, LC50 was at least 10 times more efficient inhibiting P. falciparum multidrug resistant Dd2 strain than chloroquine and mefloquine and as efficient as artemisinin (ART), artesunate and dihydroartemisinin. All three ozonides showed high efficacy in clearing parasitaemia in mice, caused by multi-drug resistant Plasmodium chabaudi strains, by subcutaneous administration, demonstrating high efficacy in vivo against ART and artesunate resistant parasites. PMID:27276364

  20. Targeting imperfect vaccines against drug-resistance determinants: a strategy for countering the rise of drug resistance.

    Directory of Open Access Journals (Sweden)

    Regina Joice

    Full Text Available The growing prevalence of antimicrobial resistance in major pathogens is outpacing discovery of new antimicrobial classes. Vaccines mitigate the effect of antimicrobial resistance by reducing the need for treatment, but vaccines for many drug-resistant pathogens remain undiscovered or have limited efficacy, in part because some vaccines selectively favor pathogen strains that escape vaccine-induced immunity. A strain with even a modest advantage in vaccinated hosts can have high fitness in a population with high vaccine coverage, which can offset a strong selection pressure such as antimicrobial use that occurs in a small fraction of hosts. We propose a strategy to target vaccines against drug-resistant pathogens, by using resistance-conferring proteins as antigens in multicomponent vaccines. Resistance determinants may be weakly immunogenic, offering only modest specific protection against resistant strains. Therefore, we assess here how varying the specific efficacy of the vaccine against resistant strains would affect the proportion of drug-resistant vs. -sensitive strains population-wide for three pathogens--Streptococcus pneumoniae, Staphylococcus aureus, and influenza virus--in which drug resistance is a problem. Notably, if such vaccines confer even slightly higher protection (additional efficacy between 1% and 8% against resistant variants than sensitive ones, they may be an effective tool in controlling the rise of resistant strains, given current levels of use for many antimicrobial agents. We show that the population-wide impact of such vaccines depends on the additional effect on resistant strains and on the overall effect (against all strains. Resistance-conferring accessory gene products or resistant alleles of essential genes could be valuable as components of vaccines even if their specific protective effect is weak.

  1. Drug resistance in the sexually transmitted protozoan Trichomonas vaginalis

    Institute of Scientific and Technical Information of China (English)

    REBECCA L DUNNE; LINDA A DUNN; PETER UPCROFT; PETER J O'DONOGHUE; JACQUELINE A UPCROFT

    2003-01-01

    Trichomoniasis is the most common, sexually transmitted infection. It is caused by the flagellated protozoan parasite Trichomonas vaginalis. Symptoms include vaginitis and infections have been associated with preterm delivery, low birth weight and increased infant mortality, as well as predisposing to HIV/AIDS and cervical cancer. Trichomoniasis has the highest prevalence and incidence of any sexually transmitted infection. The 5-nitroimidazole drugs, of which metronidazole is the most prescribed, are the only approved,effective drugs to treat trichomoniasis. Resistance against metronidazole is frequently reported and crossresistance among the family of 5-nitroimidazole drugs is common, leaving no alternative for treatment, with some cases remaining unresolved. The mechanism of metronidazole resistance in T. vaginalis from treatment failures is not well understood, unlike resistance which is developed in the laboratory under increasing metronidazole pressure. In the latter situation, hydrogenosomal function which is involved in activation of the prodrug, metronidazole, is down-regulated. Reversion to sensitivity is incomplete after removal of drug pressure in the highly resistant parasites while clinically resistant strains, so far analysed, maintain their resistance levels in the absence of drug pressure. Although anaerobic resistance has been regarded as a laboratory induced phenomenon, it clearly has been demonstrated in clinical isolates. Pursuit of both approaches will allow dissection of the underlying mechanisms. Many alternative drugs and treatments have been tested in vivo in cases of refractory trichomoniasis, as well as in vitro with some successes including the broad spectrum anti-parasitic drug nitazoxanide. Drug resistance incidence in T. vaginalis appears to be on the increase and improved surveillance of treatment failures is urged.

  2. Fitness of Leishmania donovani parasites resistant to drug combinations.

    OpenAIRE

    Raquel García-Hernández; Verónica Gómez-Pérez; Santiago Castanys; Francisco Gamarro

    2015-01-01

    Drug resistance represents one of the main problems for the use of chemotherapy to treat leishmaniasis. Additionally, it could provide some advantages to Leishmania parasites, such as a higher capacity to survive in stress conditions. In this work, in mixed populations of Leishmania donovani parasites, we have analyzed whether experimentally resistant lines to one or two combined anti-leishmanial drugs better support the stress conditions than a susceptible line expressing luciferase (Luc lin...

  3. Tiagabine add-on for drug-resistant partial epilepsy

    OpenAIRE

    Pereira, J; Marson, A G; Hutton, J L

    2012-01-01

    Cochrane Database Syst Rev. 2002;(3):CD001908. Tiagabine add-on for drug-resistant partial epilepsy. Pereira J, Marson AG, Hutton JL. Servico de Neurologia, Hospital de Santo Antonio, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal. Abstract BACKGROUND: Epilepsy is a common neurological condition, affecting almost 0.5 to 1 per cent of the population. Nearly 30 per cent of people with epilepsy are resistant to currently available drugs. Tiagabine...

  4. 真菌的多向耐药性ABC转运蛋白%Pleiotropic drug resistance ABC transporters in fungi

    Institute of Scientific and Technical Information of China (English)

    王倩; 崔志峰

    2011-01-01

    Overexpression of pleiotropic drug resistance (PDR) efflux pumps of the ATP-binding cassette (ABC) transporter superfamily is the major cause of fungal multi-drug resistance and decreased efficacy of antifungal drugs. This review focused on recent progresses in understanding of the PDR efflux pumps of ABC transporter superfamily in Saccharo-myces cerevisiae and the fungal pathogens Candida albicans, Cryptococcus neoformans, and Aspergillus fumigates. The mechanisms underlying efflux pump-mediated drug resistance and the regulatory networks involved were discussed. Investigation of the PDR efflux pumps of ABC transporter superfamily and their impact on drug resistance may lead to strategies to overcome fungal multi-drug resistance and improve drug efficacy.%真菌的多向耐药性ABC转运蛋白(ATP-binding cassette transporters)是导致多药耐药性和抗真菌药物治疗效果明显下降的主要原因.文章对酿酒酵母(accharomyces cerevisiae)和主要致病真菌白色假丝酵母(Candida albicans)、新型隐球酵母(Cryptococcus neoformans)和烟曲霉(Aspergillus fumigatus)中的多向耐药性ABC转运蛋白的种类、药物外排机制以及基因表达调控网络的研究进展作一综述,为深入了解真菌的多向耐药性机制以及探讨克服多向耐药性的策略和提高药效提供参考.

  5. Nanodrug Formed by Coassembly of Dual Anticancer Drugs to Inhibit Cancer Cell Drug Resistance.

    Science.gov (United States)

    Zhao, Yuanyuan; Chen, Fei; Pan, Yuanming; Li, Zhipeng; Xue, Xiangdong; Okeke, Chukwunweike Ikechukwu; Wang, Yifeng; Li, Chan; Peng, Ling; Wang, Paul C; Ma, Xiaowei; Liang, Xing-Jie

    2015-09-01

    Carrier-free pure nanodrugs (PNDs) that are composed entirely of pharmaceutically active molecules are regarded as promising candidates to be the next generation of drug formulations and are mainly formulated from supramolecular self-assembly of drug molecules. It benefits from the efficient use of drug compounds with poor aqueous solubility and takes advantage of nanoscale drug delivery systems. Here, a type of all-in-one nanoparticle consisting of multiple drugs with enhanced synergistic antiproliferation efficiency against drug-resistant cancer cells has been created. To nanoparticulate the anticancer drugs, 10-hydroxycamptothecin (HCPT) and doxorubicin (DOX) were chosen as a typical model. The resulting HD nanoparticles (HD NPs) were formulated by a "green" and convenient self-assembling method, and the water-solubility of 10-hydroxycamptothecin (HCPT) was improved 50-fold after nanosizing by coassembly with DOX. The formation process was studied by observing the morphological changes at various reaction times and molar ratios of DOX to HCPT. Molecular dynamics (MD) simulations showed that DOX molecules tend to assemble around HCPT molecules through intermolecular forces. With the advantage of nanosizing, HD NPs could improve the intracellular drug retention of DOX to as much as 2-fold in drug-resistant cancer cells (MCF-7R). As a dual-drug-loaded nanoformulation, HD NPs effectively enhanced drug cytotoxicity to drug-resistant cancer cells. The combination of HCPT and DOX exhibited a synergistic effect as the nanosized HD NPs improved drug retention in drug-resistant cancer cells against P-gp efflux in MCF-7R cells. Furthermore, colony forming assays were applied to evaluate long-term inhibition of cancer cell proliferation, and these assays confirmed the greatly improved cytotoxicity of HD NPs in drug-resistant cells compared to free drugs. PMID:26270258

  6. Identifying clinically relevant drug resistance genes in drug-induced resistant cancer cell lines and post-chemotherapy tissues.

    Science.gov (United States)

    Tong, Mengsha; Zheng, Weicheng; Lu, Xingrong; Ao, Lu; Li, Xiangyu; Guan, Qingzhou; Cai, Hao; Li, Mengyao; Yan, Haidan; Guo, You; Chi, Pan; Guo, Zheng

    2015-12-01

    Until recently, few molecular signatures of drug resistance identified in drug-induced resistant cancer cell models can be translated into clinical practice. Here, we defined differentially expressed genes (DEGs) between pre-chemotherapy colorectal cancer (CRC) tissue samples of non-responders and responders for 5-fluorouracil and oxaliplatin-based therapy as clinically relevant drug resistance genes (CRG5-FU/L-OHP). Taking CRG5-FU/L-OHP as reference, we evaluated the clinical relevance of several types of genes derived from HCT116 CRC cells with resistance to 5-fluorouracil and oxaliplatin, respectively. The results revealed that DEGs between parental and resistant cells, when both were treated with the corresponding drug for a certain time, were significantly consistent with the CRG5-FU/L-OHP as well as the DEGs between the post-chemotherapy CRC specimens of responders and non-responders. This study suggests a novel strategy to extract clinically relevant drug resistance genes from both drug-induced resistant cell models and post-chemotherapy cancer tissue specimens.

  7. Salicylic acid in the induction of resistance to beet seedling damping-off and antifungal activity against Fusarium sp., in vitro

    OpenAIRE

    Douglas Junior Bertoncelli; Sérgio Miguel Mazaro; Rita de Cacia Dosciatti Serrão Rocha; Nean Locatelli Dalacosta; Adriano Lewandowski; Américo Wagner Junior

    2016-01-01

    The damping off is the main disease that affects the beet crop during the seedling production. The aim of this study was to evaluate different salicylic acid (SA) concentrations for resistance induction against damping-off in beet seedling and its antifungal activity against Fusarium sp., in vitro condition. Treatment of beet seed was with SA solution by immersion during 5 minutes in the 0.5, 1.0, 1.5 and 2.0 mM concentrations and control (distilled water). It was used four replications with ...

  8. Phenotypic drug profiling in droplet microfluidics for better targeting of drug-resistant tumors

    Science.gov (United States)

    Sarkar, S.; Cohen, N.; Sabhachandani, P.; Konry, T.

    2015-01-01

    Acquired drug resistance is a key factor in the failure of chemotherapy. Due to intratumoral heterogeneity, cancer cells depict variations in intracellular drug uptake and efflux at the single cell level, which may not be detectable in bulk assays. In this study we present a droplet microfluidics-based approach to assess the dynamics of drug uptake, efflux and cytotoxicity in drug-sensitive and drug-resistant breast cancer cells. An integrated droplet generation and docking microarray was utilized to encapsulate single cells as well as homotypic cell aggregates. Drug-sensitive cells showed greater death in the presence or absence of Doxorubicin (Dox) compared to the drug-resistant cells. We observed heterogeneous Dox uptake in individual drug-sensitive cells while the drug-resistant cells showed uniformly low uptake and retention. Dox-resistant cells were classified into distinct subsets based on their efflux properties. Cells that showed longer retention of extracellular reagents also demonstrated maximal death. We further observed homotypic fusion of both cell types in droplets, which resulted in increased cell survival in the presence of high doses of Dox. Our results establish the applicability of this microfluidic platform for quantitative drug screening in single cells and multicellular interactions. PMID:26456240

  9. Chalcone derivatives as potential antifungal agents: Synthesis, and antifungal activity

    OpenAIRE

    Deepa Gupta; Jain, D. K.

    2015-01-01

    Much research has been carried out with the aim to discover the therapeutic values of chalcone derivatives. Chalcones possess wide range of pharmacological activity such as antibacterial, antimalarial, antiprotozoal, antitubercular, anticancer, and antifungal agents etc. The presence of reactive α,β-unsaturated keto group in chalcones is found to be responsible for their biological activity. The rapid developments of resistance to antifungal agents, led to design, and synthesize the new antif...

  10. Sphingolipids in neuroblastoma : Their role in drug resistance mechanisms

    NARCIS (Netherlands)

    Sietsma, H; Dijkhuis, AJ; Kamps, W; Kok, JW

    2002-01-01

    Disseminated neuroblastoma usually calls for chemotherapy as the primary approach for treatment. Treatment failure is often attributable to drug resistance. This involves a variety of cellular mechanisms, including increased drug efflux through expression of ATP-binding cassette transporters (e.g.,

  11. Mechanisms of acquired resistance to androgen receptor targeting drugs in castration resistant prostate cancer

    OpenAIRE

    Chism, David D.; De Silva, Dinuka; Whang, Young E.

    2014-01-01

    After initial response to androgen receptor targeting drugs abiraterone or enzalutamide, most patients develop progressive disease and therefore, castration resistant prostate cancer (CRPC) remains a terminal disease. Multiple mechanisms underlying acquired resistance have been postulated. Intratumoral androgen synthesis may resume after abiraterone treatment. A point mutation in the ligand binding domain of androgen receptor may confer resistance to enzalutamide. Emergence of androgen recept...

  12. (Post-)genomic approaches to tackle drug resistance in Leishmania

    OpenAIRE

    Berg, Maya; Mannaert, An; Vanaerschot, Manu; Van Der Auwera, Gert; Dujardin, Jean-Claude

    2013-01-01

    Abstract: Leishmaniasis, like other neglected diseases is characterized by a small arsenal of drugs for its control. To safeguard the efficacy of current drugs and guide the development of new ones it is thus of utmost importance to acquire a deep understanding of the phenomenon of drug resistance and its link with treatment outcome. We discuss here how (post-) genomic approaches may contribute to this purpose. We highlight the need for a clear definition of the phenotypes under consideration...

  13. Study on Drug Resistance and Relative Mechanisms of Chlamydia Trachomatis

    Institute of Scientific and Technical Information of China (English)

    侯淑萍; 刘全忠

    2004-01-01

    Abstract: Chlamydia Trachomatis (C.T.) is one of the most common pathogens of human sexually transmitted diseases. Treatment of C.T. infection primarily depends on Tetracyclines, Macrolides and Quinolones, but with the wide use of antibiotics an increasing number of drug-resistant Chlamydia trachomatis cases have been reported. This review summarizes the resistant conditions and the possible resistance mechanisms of C.T..

  14. Troglitazone reverses the multiple drug resistance phenotype in cancer cells

    Directory of Open Access Journals (Sweden)

    Gerald F Davies

    2009-03-01

    Full Text Available Gerald F Davies1, Bernhard HJ Juurlink2, Troy AA Harkness11Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, Canada; 2College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi ArabiaAbstract: A major problem in treating cancer is the development of drug resistance. We previously demonstrated doxorubicin (DOX resistance in K562 human leukemia cells that was associated with upregulation of glyoxalase 1 (GLO-1 and histone H3 expression. The thiazolidinedione troglitazone (TRG downregulated GLO-1 expression and further upregulated histone H3 expression and post-translational modifications in these cells, leading to a regained sensitivity to DOX. Given the pleiotropic effects of epigenetic changes in cancer development, we hypothesized that TRG may downregulate the multiple drug resistance (MDR phenotype in a variety of cancer cells. To test this, MCF7 human breast cancer cells and K562 cells were cultured in the presence of low-dose DOX to establish DOX-resistant cell lines (K562/DOX and MCF7/DOX. The MDR phenotype was confirmed by Western blot analysis of the 170 kDa P-glycoprotein (Pgp drug efflux pump multiple drug resistance protein 1 (MDR-1, and the breast cancer resistance protein (BCRP. TRG markedly decreased expression of both MDR-1 and BCRP in these cells, resulting in sensitivity to DOX. Silencing of MDR-1 expression also sensitized MCF7/DOX cells to DOX. Use of the specific and irreversible peroxisome proliferator-activated receptor gamma (PPARγ inhibitor GW9662 in the nanomolar range not only demonstrated that the action of TRG on MCF/DOX was PPARγ-independent, but indicated that PPARγ may play a role in the MDR phenotype, which is antagonized by TRG. We conclude that TRG is potentially a useful adjunct therapy in chemoresistant cancers. Keywords: chemotherapy, doxorubicin, breast cancer resistance protein-1, multiple drug resistance, multiple drug resistance protein 1

  15. Extensively Drug-Resistant Tuberculosis (XDR TB)

    Science.gov (United States)

    ... American Community Summit Background Slideset Children Correctional Facilities Homelessness International Travelers Pregnancy Health Disparities Laboratory Information Model Performance Evaluation Program (MPEP) Drug Susceptibility Testing The Uses of Nucleic Acid Amplification ...

  16. Design, synthesis and molecular docking studies of novel triazole antifungal compounds

    Institute of Scientific and Technical Information of China (English)

    Qiu Qin He; Ke Li; Yong Bing Cao; Huan Wen Dong; Li Hua Zhao; Chao Mei Liu; Chun Quan Sheng

    2007-01-01

    Based on the active site of Candida albicans lanosterol 14α-demethylase (CACYP51), novel triazole compounds structurally different from the current triazole drugs were designed and synthesized.In vitro antifungal activities showed that compounds 10,11,16 and 20 exhibited strong activities.In addition, compounds 10,11 and 16 also displayed certain activities against fluconazole-resistant fungi.

  17. INDUCTION OF DRUG RESISTANCE IN PLASMODIUM FALCIPARUM: AN INTERMITTENT DRUG EXPOSURE METHOD

    Directory of Open Access Journals (Sweden)

    M.Nateghpour

    1998-03-01

    Full Text Available The production of experimentally induced drug resistance in the laboratory provides valuable opportunities for investigators to study the nature and genetics of drug resistance mechanisms to a given agent, patterns of cross resistance and the mode of action of drugs. At the beginning the continuous drug exposure was chosen as a standard procedure to produce drug— resistant strains of P. falciparum,.but later on some other methods were also applied. An intermittent drug exposure method as a novel procedure has been introduced in this study. Intermittent exposure of chloroquine resistant Kl and chloroquine sensitive T9.96 strains of P. falciparum to halofantrine culminated in a relatively rapid reduction in sensitivity to the drug. The response of halofantrifle - resistnat K1HF and T9.96 strains and parent parasites to halofantrifle, inefloquine, quinine and chloroquine was determined. The results indicated that the effectiveness of halofantrine to K1HF and T9.96HF strains decreased 9 and 3 folds respectively, compared to the parent parasites. Cross -resistance occurred among halofantrine. mefloquine and quinine. Halofantrine resistance was associated with enhanced chloroquine sensitivity in the strain derived from chloroquine - resistant K1 strain, hut not in the strain derived from chloroquine - sensitive T9.96 parasites.

  18. Drug resistance pattern among afb smear positive retreatment completed cases

    International Nuclear Information System (INIS)

    Worldwide, multidrug resistance (MDR TB) is a serious issue. It has increased over the last decade. Re-treatment completed sputum smear positive cases have much higher incidence of MDR- TB as compared to primary MDR - TB. Objective: To estimate the incidence of drug resistance pattern among AFB smear positive re-treatment completed cases. Study Design: Evidence based prospective study. Study Setting: Institute of Chest Medicine, Mayo Hospital Lahore, Tertiary care hospital affiliated with King Edward Medical University, Lahore, Pakistan. Methodology: A total 50 (Male 22, Female 28) pulmonary TB patients who had completed Re- treatment regimen in the past and are still sputum smear positive for acid fast Bacilli were included in the study. Three consecutive sputum specimens were collected at Aga Khan University collection center at Lahore. The specimen were sent to Aga Khan University Lab Karachi for AFB smear, culture and drug sensitivity both for essential and reserve drugs. Reports for AFB smear were received within a week, while culture and drug sensitivity' reports after 6 weeks. Reports data was analyzed for essential and reserve anti tuberculous drug sensitivity for mycobacterium tuberculosis. Results: Data Analysis revealed MDR TB in 31(62%) patients which include 11 males and 23 females. Individual drug resistance to essential drugs was INH - 62%, Rifampicin - 68%, Ethambutol - 24%, PZA - 25% and Streptomycin - 21 %. Poly drug resistance was determined in' 38% cases. Individual drug resistance to reserve drugs - kanamycin, Amikacin, ofloxacin, Ethionamide and PAS was 4%, 4%, 36%, 10% and 2% respectively. Conclusion: There is a very high proportion of MDR TB in sputum smear AFB positive retreatment cases. Suggestion: Comprehensive measures including DO- TS PLUS are needed to control MDR TB in Pakistan. (author)

  19. Modeling and predicting drug resistance rate and strength.

    Science.gov (United States)

    Fullybright, R; Dwivedi, A; Mallawaarachchi, I; Sinsin, B

    2016-08-01

    Drug resistance has been worsening in human infectious diseases medicine over the past several decades. Our ability to successfully control resistance depends to a large extent on our understanding of the features characterizing the process. Part of that understanding includes the rate at which new resistance has been emerging in pathogens. Along that line, resistance data covering 90 infectious diseases, 118 pathogens, and 337 molecules, from 1921 through 2007, are modeled using various statistical tools to generate regression models for the rate of new resistance emergence and for cumulative resistance build-up in pathogens. Thereafter, the strength of the association between the number of molecules put on the market and the number of resulting cases of resistance is statistically tested. Predictive models are presented for the rate at which new resistance has been emerging in infectious diseases medicine, along with predictive models for the rate of cumulative resistance build-up in the aggregate of 118 pathogens as well as in ten individual pathogens. The models are expressed as a function of time and/or as a function of the number of molecules put on the market by the pharmaceutical industry. It is found that molecules significantly induce resistance in pathogens and that new or cumulative drug resistance across infectious diseases medicine has been arising at exponential rates. PMID:27209288

  20. Supramolecular Antibiotic Switches: A Potential Strategy for Combating Drug Resistance.

    Science.gov (United States)

    Bai, Haotian; Lv, Fengting; Liu, Libing; Wang, Shu

    2016-08-01

    Bacterial infectious disease is a serious public health concern throughout the world. Pathogen drug resistance, arising from both rational use and abuse/misuse of germicides, complicates the situation. Aside from developing novel antibiotics and antimicrobial agents, molecular approaches have become another significant method to overcome the problem of pathogen drug resistance. Established supramolecular systems, the antibiotic properties of which can be switched "on" and "off" through host-guest interactions, show great potential in combating issues regarding antibiotic resistance in the long term, as indicated by several recent studies. In this Concept, recently developed strategies for antibacterial regulation are summarized and further directions for research into antibiotic switches are proposed. PMID:27312106

  1. Topical antifungals for seborrhoeic dermatitis

    OpenAIRE

    Okokon, Enembe O; Verbeek, Jos H.; Ruotsalainen, Jani H; Ojo, Olumuyiwa A; Bakhoya, Victor Nyange

    2015-01-01

    Background Seborrhoeic dermatitis is a chronic inflammatory skin condition that is distributed worldwide. It commonly affects the scalp, face and flexures of the body. Treatment options include antifungal drugs, steroids, calcineurin inhibitors, keratolytic agents and phototherapy. Objectives To assess the effects of antifungal agents for seborrhoeic dermatitis of the face and scalp in adolescents and adults. A secondary objective is to assess whether the same interventions are effective in t...

  2. Nanoparticles: Alternatives Against Drug-Resistant Pathogenic Microbes.

    Science.gov (United States)

    Rudramurthy, Gudepalya Renukaiah; Swamy, Mallappa Kumara; Sinniah, Uma Rani; Ghasemzadeh, Ali

    2016-01-01

    Antimicrobial substances may be synthetic, semisynthetic, or of natural origin (i.e., from plants and animals). Antimicrobials are considered "miracle drugs" and can determine if an infected patient/animal recovers or dies. However, the misuse of antimicrobials has led to the development of multi-drug-resistant bacteria, which is one of the greatest challenges for healthcare practitioners and is a significant global threat. The major concern with the development of antimicrobial resistance is the spread of resistant organisms. The replacement of conventional antimicrobials by new technology to counteract antimicrobial resistance is ongoing. Nanotechnology-driven innovations provide hope for patients and practitioners in overcoming the problem of drug resistance. Nanomaterials have tremendous potential in both the medical and veterinary fields. Several nanostructures comprising metallic particles have been developed to counteract microbial pathogens. The effectiveness of nanoparticles (NPs) depends on the interaction between the microorganism and the NPs. The development of effective nanomaterials requires in-depth knowledge of the physicochemical properties of NPs and the biological aspects of microorganisms. However, the risks associated with using NPs in healthcare need to be addressed. The present review highlights the antimicrobial effects of various nanomaterials and their potential advantages, drawbacks, or side effects. In addition, this comprehensive information may be useful in the discovery of broad-spectrum antimicrobial drugs for use against multi-drug-resistant microbial pathogens in the near future. PMID:27355939

  3. Anti tuberculosis drug resistance in west of Iran

    Directory of Open Access Journals (Sweden)

    Parviz Mohajeri

    2014-01-01

    Full Text Available Background and Objective: Mycobacterium tuberculosis has developed resistance to antituberculosis drugs and becoming a major and alarming public health problem in worldwide. This study was aimed to determine antituberculosis drug resistance rate and to identify multidrug resistant tuberculosis (MDR-TB in West of Iran. Materials and Methods: Of 130 samples were included between December 2011 and July 2012 in the study from that 112 cases were M. tuberculosis. The proportional method was carried out according to the Clinical and Laboratory Standards Institute on Lowenstein-Jensen against isoniazid, rifampicin, streptomycin, ethambutol, pyrazinamide, para aminosalicylic acid, ethionamide, cycloserine (CYC. The microdilution method was carried out using 7H9 broth with 96 well-plates. Results: From 112 isolates, resistance was observed to isoniazid 18 (16.07%, rifampicin 16 (14.28%, streptomycin 25 (22.32%, ethambutol 15 (13.39%, pyrazinamide 27 (24.10%, para aminosalicylic acid 19 (16.96%, CYC 4 (3.57%, and ethionamide 14 (12.5% cases. 16 isolates were MDR. Conclusion: The high prevalence of MDR-TB in our study is assumed to be due to recent transmission of drug-resistant strains. Overall, the rate of drug resistance in our study was high, which is in line with findings of some high-burden countries. Hence that early case detection, rapid drug susceptibility testing, and effective anti-TB treatment is necessary.

  4. Challenges of drug resistance in the management of pancreatic cancer.

    LENUS (Irish Health Repository)

    Sheikh, Rizwan

    2012-02-01

    The current treatment of choice for metastatic pancreatic cancer involves single-agent gemcitabine or a combination of gemcitabine with capecitabine or erlotinib (a tyrosine kinase inhibitor). Only 25–30% of patients respond to this treatment and patients who do respond initially ultimately exhibit disease progression. Median survival for pancreatic cancer patients has reached a plateau due to inherent and acquired resistance to these agents. Key molecular factors implicated in this resistance include: deficiencies in drug uptake, alteration of drug targets, activation of DNA repair pathways, resistance to apoptosis and the contribution of the tumor microenvironment. Moreover, for newer agents including tyrosine kinase inhibitors, overexpression of signaling proteins, mutations in kinase domains, activation of alternative pathways, mutations of genes downstream of the target and\\/or amplification of the target represent key challenges for treatment efficacy. Here we will review the contribution of known mechanisms and markers of resistance to key pancreatic cancer drug treatments.

  5. Long non-coding RNAs in cancer drug resistance development.

    Science.gov (United States)

    Majidinia, Maryam; Yousefi, Bahman

    2016-09-01

    The presence or emergence of chemoresistance in tumor cells is a major burden in cancer therapy. While drug resistance is a multifactorial phenomenon arising from altered membrane transport of drugs, altered drug metabolism, altered DNA repair, reduced apoptosis rate and alterations of drug metabolism, it can also be linked to genetic and epigenetic factors. Long non-coding RNAs (lncRNAs) have important regulatory roles in many aspects of genome function including gene transcription, splicing, and epigenetics as well as biological processes involved in cell cycle, cell differentiation, development, and pluripotency. As such, it may not be surprising that some lncRNAs have been recently linked to carcinogenesis and drug resistance/sensitivity. Research is accelerating to decipher the exact molecular mechanism of lncRNA-regulated drug resistance and its therapeutic implications. In this article, we will review the structure, biogenesis, and mode of action of lncRNAs. Then, the involvement of lncRNAs in drug resistance will be discussed in detail. PMID:27427176

  6. Developing artemisinin based drug combinations for the treatment of drug resistant falciparum malaria: A review

    Directory of Open Access Journals (Sweden)

    Olliaro P

    2004-01-01

    Full Text Available The emergence and spread of drug resistant malaria represents a considerable challenge to controlling malaria. To date, malaria control has relied heavily on a comparatively small number of chemically related drugs, belonging to either the quinoline or the antifolate groups. Only recently have the artemisinin derivatives been used but mostly in south east Asia. Experience has shown that resistance eventually curtails the life-span of antimalarial drugs. Controlling resistance is key to ensuring that the investment put into developing new antimalarial drugs is not wasted. Current efforts focus on research into new compounds with novel mechanisms of action, and on measures to prevent or delay resistance when drugs are introduced. Drug discovery and development are long, risky and costly ventures. Antimalarial drug development has traditionally been slow but now various private and public institutions are at work to discover and develop new compounds. Today, the antimalarial development pipeline is looking reasonably healthy. Most development relies on the quinoline, antifolate and artemisinin compounds. There is a pressing need to have effective, easy to use, affordable drugs that will last a long time. Drug combinations that have independent modes of action are seen as a way of enhancing efficacy while ensuring mutual protection against resistance. Most research work has focused on the use of artesunate combined with currently used standard drugs, namely, mefloquine, amodiaquine, sulfadoxine/pyrimethamine, and chloroquine. There is clear evidence that combinations improve efficacy without increasing toxicity. However, the absolute cure rates that are achieved by combinations vary widely and depend on the level of resistance of the standard drug. From these studies, further work is underway to produce fixed dose combinations that will be packaged in blister packs. This review will summarise current antimalarial drug developments and outline recent

  7. Comparative Evaluation of FUNGITEST and Broth Microdilution Methods for Antifungal Drug Susceptibility Testing of Candida Species and Cryptococcus neoformans

    OpenAIRE

    Davey, Kate G.; Holmes, Ann D.; Elizabeth M. Johnson; Szekely, Adrien; Warnock, David W.

    1998-01-01

    The FUNGITEST method (Sanofi Diagnostics Pasteur, Paris, France) is a microplate-based procedure for the breakpoint testing of six antifungal agents (amphotericin B, flucytosine, fluconazole, itraconazole, ketoconazole, and miconazole). We compared the FUNGITEST method with a broth microdilution test, performed according to National Committee for Clinical Laboratory Standards document M27-A guidelines, for determining the in vitro susceptibilities of 180 isolates of Candida spp. (50 C. albica...

  8. Chalcone derivatives as potential antifungal agents: Synthesis, and antifungal activity

    Directory of Open Access Journals (Sweden)

    Deepa Gupta

    2015-01-01

    Full Text Available Much research has been carried out with the aim to discover the therapeutic values of chalcone derivatives. Chalcones possess wide range of pharmacological activity such as antibacterial, antimalarial, antiprotozoal, antitubercular, anticancer, and antifungal agents etc. The presence of reactive α,β-unsaturated keto group in chalcones is found to be responsible for their biological activity. The rapid developments of resistance to antifungal agents, led to design, and synthesize the new antifungal agents. The derivatives of chalcones were prepared using Claisen-Schmidt condensation scheme with appropriate tetralone and aldehyde derivatives. Ten derivatives were synthesized and were biologically screened for antifungal activity. The newly synthesized derivatives of chalcone showed antifungal activity against fungal species, Microsporum gypseum. The results so obtained were superior or comparable to ketoconazole. It was observed that none of the compounds tested showed positive results for fungi Candida albicans nor against fungi Aspergillus niger. Chalcone derivatives showed inhibitory effect against M. gypseum species of fungus. It was found that among the chalcone derivatives so synthesized, two of them, that is, 4-chloro derivative, and unsubstituted derivative of chalcone showed antifungal activity superior to ketoconazole. Thus, these can be the potential new molecule as antifungal agent.

  9. Dynamics of immune response and drug resistance in malaria infection

    Directory of Open Access Journals (Sweden)

    Gurarie David

    2006-10-01

    Full Text Available Abstract Background Malaria parasites that concurrently infect a host compete on the basis of their intrinsic growth rates and by stimulating cross-reactive immune responses that inhibit each others' growth. If the phenotypes also show different drug sensitivities ('sensitive' vs. 'resistant' strains, drug treatment can change their joint dynamics and the long-term outcome of the infection: most obviously, persistent drug pressure can permit the more resistant, but otherwise competitively-inferior, strains to dominate. Methods Here a mathematical model is developed to analyse how these and more subtle effects of antimalarial drug use are modulated by immune response, repeated re-inoculation of parasites, drug pharmacokinetic parameters, dose and treatment frequency. Results The model quantifies possible effects of single and multiple (periodic treatment on the outcome of parasite competition. In the absence of further inoculation, the dosage and/or treatment frequency required for complete clearance can be estimated. With persistent superinfection, time-average parasite densities can be derived in terms of the basic immune-regulating parameters, the drug efficacy and treatment regimen. Conclusion The functional relations in the model are applicable to a wide range of conditions and transmission environments, allowing predictions to be made on both the individual and the community levels, and, in particular, transitions from drug-sensitive to drug-resistant parasite dominance to be projected on both levels.

  10. HIV resistance testing and detected drug resistance in Europe

    DEFF Research Database (Denmark)

    Schultze, Anna; Phillips, Andrew N; Paredes, Roger;

    2015-01-01

    calculated using logistic regression with generalized estimating equations. RESULTS: Compared to 74.2% of ART-experienced individuals in 1997, only 5.1% showed evidence of virological failure in 2012. The odds of resistance testing declined after 2004 (global P 

  11. The action of Pseudomonas aeruginosa biofilms in intrinsic drug resistance

    Institute of Scientific and Technical Information of China (English)

    XIE Yi; JIA Wen-xiang; ZENG Wei; YANG Wei-qing; CHENG Xi; LI Xue-ru; WANG Lan-lan; KANG Mei; ZHANG Zai-rong

    2005-01-01

    Background There is a growing interest in studying the relationship between intrinsic resistance and biofilms resistance to drugs. However, the relationship still remains unclear in the macroscopic bacterial growth. Our study is to illuminate the change of bacterial drug resistance of gyrA mutant and active efflux pump during the development of Pseudomonas aeruginosa (P. aeruginosa) biofilms. Methods The strains of type Ⅱ topoisomerase gene mutant (gyrA mutant) and multidrug resistance (MDR) efflux pump were clinical isolates and detected by polymerase chain reaction (PCR). The process of bacterial biofilms development was observed by scanning electron microscope. Triparental mating experiments were performed to transfer report gene of green fluorescent protein (GFP) into P. aeruginosa biofilms strains and followed by analysis of bacterial survival rate between intrinsic resistance and biofilms resistance.Results The fluorescent strains with pGFPuv could develop mature biofilms on Teflon surface. Before a period of 72 hours, the survival rate of biofilms bacteria and intrinsic resistance strains in ciprofloxacin solution was significantly different (P0.05). The carbonyl cyanide m-chlorophenylhydrazone and azithromycin could significantly reduce the drug resistance of biofilm strains and efflux pump strains.Conclusions In the development of P. aeruginosa biofilms, the strains of gyrA mutation and MDR efflux could be conferred with new level of drug resistance. When co-cultured mutated strains with biofilm strains, biofilms may play a major role in bacterial resistance. But after 72 hours incubation (a mature biofilms had been developed), there was no clearly difference between the number of mutant strains and biofilm strains.

  12. Efflux Pump-mediated Drug Resistance in Burkholderia

    Directory of Open Access Journals (Sweden)

    Nicole L Podnecky

    2015-04-01

    Full Text Available Several members of the genus Burkholderia are prominent pathogens. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. Virtually all Burkholderia species are also resistant to polymyxin, prohibiting use of drugs like colistin that are available for treatment of infections caused by most other drug resistant Gram-negative bacteria. Despite clinical significance and antibiotic resistance of Burkholderia species, characterization of efflux pumps lags behind other non-enteric Gram-negative pathogens such as Acinetobacter baumannii and Pseudomonas aeruginosa. Although efflux pumps have been described in several Burkholderia species, they have been best studied in B. cenocepacia and B. pseudomallei. As in other non-enteric Gram-negatives, efflux pumps of the resistance nodulation cell division (RND family are the clinically most significant efflux systems in these two species. Several efflux pumps were described in B. cenocepacia, which when expressed confer resistance to clinically significant antibiotics, including aminoglycosides, chloramphenicol, fluoroquinolones, and tetracyclines. Three RND pumps have been characterized in B. pseudomallei, two of which confer either intrinsic or acquired resistance to aminoglycosides, macrolides, chloramphenicol, fluoroquinolones, tetracyclines, trimethoprim, and in some instances trimethoprim+sulfamethoxazole. Several strains of the host-adapted B. mallei, a clone of B. pseudomallei, lack AmrAB-OprA and are therefore aminoglycoside and macrolide susceptible. B. thailandensis is closely related to B. pseudomallei, but non-pathogenic to humans. Its pump repertoire and ensuing drug resistance profile parallels that of B. pseudomallei. An efflux pump in B. vietnamiensis plays a significant role in acquired aminoglycoside resistance. Summarily, efflux pumps are significant players in Burkholderia drug resistance.

  13. Drug efflux proteins in multidrug resistant bacteria

    NARCIS (Netherlands)

    vanVeen, HW; Konings, WN

    1997-01-01

    Bacteria contain an array of transport proteins in their cytoplasmic membrane. Many of these proteins play an important role in conferring resistance to toxic compounds. The multidrug efflux systems encountered in prokaryotic cells are very similar to those observed in eukaryotic cells. Therefore, a

  14. Potential risk for drug resistance globalization at the Hajj.

    Science.gov (United States)

    Al-Tawfiq, J A; Memish, Z A

    2015-02-01

    Antibiotics were once considered the miracle cure for infectious diseases. The tragedy would be the loss of these miracles as we witness increased antibiotic resistance throughout the world. One of the concerns during mass gatherings is the transmission of antibiotic resistance. Hajj is one of the most common recurring mass gatherings, attracting millions of people from around the world. The transmission of drug-resistant organisms during the Hajj is not well described. In the current review, we summarize the available literature on the transmission and acquisition of antibiotic resistance during the Hajj and present possible solutions.

  15. TWO OPTIMAL CONTROL PROBLEMS IN CANCER CHEMOTHERAPY WITH DRUG RESISTANCE

    Directory of Open Access Journals (Sweden)

    Werner Krabs

    2012-01-01

    Full Text Available We investigate two well-known basic optimal control problems forchemotherapeutic cancer treatment modified by introducing a timedependent “resistance factor”. This factor should be responsible for the effect of the drug resistance of tumor cells on the dynamical growth for the tumor. Both optimal control problems have common pointwise but different integral constraints on the control. We show that in both models the usually practised bang-bang control is optimal if the resistance is sufficiently strong. Further, we discuss different optimal strategies in both models for general resistance.

  16. Drug Repurposing Identifies Inhibitors of Oseltamivir-Resistant Influenza Viruses.

    Science.gov (United States)

    Bao, Ju; Marathe, Bindumadhav; Govorkova, Elena A; Zheng, Jie J

    2016-03-01

    The neuraminidase (NA) inhibitor, oseltamivir, is a widely used anti-influenza drug. However, oseltamivir-resistant H1N1 influenza viruses carrying the H275Y NA mutation spontaneously emerged as a result of natural genetic drift and drug treatment. Because H275Y and other potential mutations may generate a future pandemic influenza strain that is oseltamivir-resistant, alternative therapy options are needed. Herein, we show that a structure-based computational method can be used to identify existing drugs that inhibit resistant viruses, thereby providing a first line of pharmaceutical defense against this possible scenario. We identified two drugs, nalidixic acid and dorzolamide, that potently inhibit the NA activity of oseltamivir-resistant H1N1 viruses with the H275Y NA mutation at very low concentrations, but have no effect on wild-type H1N1 NA even at a much higher concentration, suggesting that the oseltamivir-resistance mutation itself caused susceptibility to these drugs. PMID:26833677

  17. Nanoparticles: Alternatives Against Drug-Resistant Pathogenic Microbes

    Directory of Open Access Journals (Sweden)

    Gudepalya Renukaiah Rudramurthy

    2016-06-01

    Full Text Available Antimicrobial substances may be synthetic, semisynthetic, or of natural origin (i.e., from plants and animals. Antimicrobials are considered “miracle drugs” and can determine if an infected patient/animal recovers or dies. However, the misuse of antimicrobials has led to the development of multi-drug-resistant bacteria, which is one of the greatest challenges for healthcare practitioners and is a significant global threat. The major concern with the development of antimicrobial resistance is the spread of resistant organisms. The replacement of conventional antimicrobials by new technology to counteract antimicrobial resistance is ongoing. Nanotechnology-driven innovations provide hope for patients and practitioners in overcoming the problem of drug resistance. Nanomaterials have tremendous potential in both the medical and veterinary fields. Several nanostructures comprising metallic particles have been developed to counteract microbial pathogens. The effectiveness of nanoparticles (NPs depends on the interaction between the microorganism and the NPs. The development of effective nanomaterials requires in-depth knowledge of the physicochemical properties of NPs and the biological aspects of microorganisms. However, the risks associated with using NPs in healthcare need to be addressed. The present review highlights the antimicrobial effects of various nanomaterials and their potential advantages, drawbacks, or side effects. In addition, this comprehensive information may be useful in the discovery of broad-spectrum antimicrobial drugs for use against multi-drug-resistant microbial pathogens in the near future.

  18. Extensively Drug-Resistant Tuberculosis: Principles of Resistance, Diagnosis, and Management.

    Science.gov (United States)

    Wilson, John W; Tsukayama, Dean T

    2016-04-01

    Extensively drug-resistant (XDR) tuberculosis (TB) is an unfortunate by-product of mankind's medical and pharmaceutical ingenuity during the past 60 years. Although new drug developments have enabled TB to be more readily curable, inappropriate TB management has led to the emergence of drug-resistant disease. Extensively drug-resistant TB describes Mycobacterium tuberculosis that is collectively resistant to isoniazid, rifampin, a fluoroquinolone, and an injectable agent. It proliferates when established case management and infection control procedures are not followed. Optimized treatment outcomes necessitate time-sensitive diagnoses, along with expanded combinations and prolonged durations of antimicrobial drug therapy. The challenges to public health institutions are immense and most noteworthy in underresourced communities and in patients coinfected with human immunodeficiency virus. A comprehensive and multidisciplinary case management approach is required to optimize outcomes. We review the principles of TB drug resistance and the risk factors, diagnosis, and managerial approaches for extensively drug-resistant TB. Treatment outcomes, cost, and unresolved medical issues are also discussed.

  19. Spread of anti-malarial drug resistance: Mathematical model with implications for ACT drug policies

    Directory of Open Access Journals (Sweden)

    Dondorp Arjen M

    2008-11-01

    Full Text Available Abstract Background Most malaria-endemic countries are implementing a change in anti-malarial drug policy to artemisinin-based combination therapy (ACT. The impact of different drug choices and implementation strategies is uncertain. Data from many epidemiological studies in different levels of malaria endemicity and in areas with the highest prevalence of drug resistance like borders of Thailand are certainly valuable. Formulating an appropriate dynamic data-driven model is a powerful predictive tool for exploring the impact of these strategies quantitatively. Methods A comprehensive model was constructed incorporating important epidemiological and biological factors of human, mosquito, parasite and treatment. The iterative process of developing the model, identifying data needed, and parameterization has been taken to strongly link the model to the empirical evidence. The model provides quantitative measures of outcomes, such as malaria prevalence/incidence and treatment failure, and illustrates the spread of resistance in low and high transmission settings. The model was used to evaluate different anti-malarial policy options focusing on ACT deployment. Results The model predicts robustly that in low transmission settings drug resistance spreads faster than in high transmission settings, and treatment failure is the main force driving the spread of drug resistance. In low transmission settings, ACT slows the spread of drug resistance to a partner drug, especially at high coverage rates. This effect decreases exponentially with increasing delay in deploying the ACT and decreasing rates of coverage. In the high transmission settings, however, drug resistance is driven by the proportion of the human population with a residual drug level, which gives resistant parasites some survival advantage. The spread of drug resistance could be slowed down by controlling presumptive drug use and avoiding the use of combination therapies containing drugs with

  20. Drug resistance mechanisms of fungal biofilms

    OpenAIRE

    Seneviratne, CJ; Samaranayake, LP

    2011-01-01

    Fungi are ubiquitous in nature and exist in soil, water, plants, and in animals and humans. Similar to bacteria, fungi also form confluent biofilms either singly (mono-species) or with other microbial species (mixed-species). Fungal biofilms are known to be highly resistant to the adverse environmental conditions including antimicrobials and biocide compared to its planktonic (free-floating) counterparts. Although bacterial biofilms have been studied in detail, relatively little is known of f...

  1. Drugs that target pathogen public goods are robust against evolved drug resistance.

    Science.gov (United States)

    Pepper, John W

    2012-11-01

    Pathogen drug resistance is a central problem in medicine and public health. It arises through somatic evolution, by mutation and selection among pathogen cells within a host. Here, we examine the hypothesis that evolution of drug resistance could be reduced by developing drugs that target the secreted metabolites produced by pathogen cells instead of directly targeting the cells themselves. Using an agent-based computational model of an evolving population of pathogen cells, we test this hypothesis and find support for it. We also use our model to explain this effect within the framework of standard evolutionary theory. We find that in our model, the drugs most robust against evolved drug resistance are those that target the most widely shared external products, or 'public goods', of pathogen cells. We also show that these drugs exert a weak selective pressure for resistance because they create only a weak correlation between drug resistance and cell fitness. The same principles apply to design of vaccines that are robust against vaccine escape. Because our theoretical results have crucial practical implications, they should be tested by empirical experiments.

  2. Enhanced transmission of drug-resistant parasites to mosquitoes following drug treatment in rodent malaria.

    Directory of Open Access Journals (Sweden)

    Andrew S Bell

    Full Text Available The evolution of drug resistant Plasmodium parasites is a major challenge to effective malaria control. In theory, competitive interactions between sensitive parasites and resistant parasites within infections are a major determinant of the rate at which parasite evolution undermines drug efficacy. Competitive suppression of resistant parasites in untreated hosts slows the spread of resistance; competitive release following treatment enhances it. Here we report that for the murine model Plasmodium chabaudi, co-infection with drug-sensitive parasites can prevent the transmission of initially rare resistant parasites to mosquitoes. Removal of drug-sensitive parasites following chemotherapy enabled resistant parasites to transmit to mosquitoes as successfully as sensitive parasites in the absence of treatment. We also show that the genetic composition of gametocyte populations in host venous blood accurately reflects the genetic composition of gametocytes taken up by mosquitoes. Our data demonstrate that, at least for this mouse model, aggressive chemotherapy leads to very effective transmission of highly resistant parasites that are present in an infection, the very parasites which undermine the long term efficacy of front-line drugs.

  3. In vitro antifungal susceptibility of Malassezia pachydermatis from dogs with and without skin lesions.

    Science.gov (United States)

    Cafarchia, Claudia; Figueredo, Luciana A; Iatta, Roberta; Montagna, Maria Teresa; Otranto, Domenico

    2012-03-23

    Canine Malassezia dermatitis is frequently treated with systemic ketoconazole (KTZ) and itraconazole (ITZ). However, no information is available on the antifungal susceptibility to azoles and allilamine of Malassezia pachydermatis isolates from dogs with or without skin lesions. The present study was designed to evaluate the in vitro antifungal susceptibility of M. pachydermatis strains from dogs with or without skin lesions to KTZ, ITZ, miconazole (MICO), fluconazole (FLZ), posaconazole (POS), voriconazole (VOR) and terbinafine (TER) using the Clinical and Laboratory Standards Institute reference Broth Microdilution Method (CLSI M27-A2). The association between the susceptibility to antifungal compounds and the origin of M. pachydermatis, from skin with or without lesions has been also assessed. A total of 62 M. pachydermatis strains from healthy dogs (i.e., Group A=30) or with skin lesions (i.e., Group B=32) were tested. ITZ, KTZ and POS showed the highest activity against M. pachydermatis strains, whereas MICO TER and FLZ the lowest. A higher number of Malassezia resistant strains were registered among isolates from Group B than those from Group A. This study indicates that M. pachydermatis strains were susceptible to ITZ, KTZ, and POS. However, dogs with lesions may harbour strains with low susceptibility to antifungal agents and displaying cross-resistance phenomena to azole. The antifungal therapy in Malassezia infections requires careful appraisal of choice of drugs especially in cases of unresponsiveness to antifungal treatment or recurrent infections. PMID:21962411

  4. New strategies against drug resistance to herpes simplex virus

    Institute of Scientific and Technical Information of China (English)

    Yu-Chen Jiang; Hui Feng; Yu-Chun Lin; Xiu-Rong Guo

    2016-01-01

    Herpes simplex virus (HSV), a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir (ACV) and related nucleoside analogues can successfully treat HSV infections, but the emergence of drug resistance to ACV has created a barrier for the treatment of HSV infections, especially in immunocompromised patients. There is an urgent need to explore new and effective tactics to circumvent drug resistance to HSV. This review summarises the current strategies in the development of new targets (the DNA helicase/primase (H/P) complex), new types of molecules (nature products) and new antiviral mechanisms (lethal mutagenesis of Janus-type nucleosides) to fight the drug resistance of HSV.

  5. HIV Drug-resistant Strains as Epidemiologic Sentinels

    Science.gov (United States)

    Grant, Robert M.; Porco, Travis C.; Getz, Wayne M.

    2006-01-01

    Observed declines in drug resistance to nucleoside reverse transcriptase inhibitors among persons recently infected with HIV-1 in monitored subpopulations can be interpreted as a positive sign and lead public health officials to decrease efforts towards HIV prevention. By means of a mathematical model, we identified 3 processes that can account for the observed decline: increase in high-risk behavior, decrease in proportion of acutely infected persons whose conditions are treated, and change in treatment efficacy. These processes, singly or in combination, can lead to increases or decreases in disease and drug-resistance prevalence in the general population. We discuss the most appropriate public health response under each scenario and emphasize how further data collection and analyses are required to more reliably evaluate the observed time trends and the relative importance of forces shaping the epidemic. Our study highlights how drug resistance markers can be used as epidemiologic sentinels to devise public health solutions. PMID:16494741

  6. New strategies against drug resistance to herpes simplex virus

    Science.gov (United States)

    Jiang, Yu-Chen; Feng, Hui; Lin, Yu-Chun; Guo, Xiu-Rong

    2016-01-01

    Herpes simplex virus (HSV), a member of the Herpesviridae family, is a significant human pathogen that results in mucocutaneous lesions in the oral cavity or genital infections. Acyclovir (ACV) and related nucleoside analogues can successfully treat HSV infections, but the emergence of drug resistance to ACV has created a barrier for the treatment of HSV infections, especially in immunocompromised patients. There is an urgent need to explore new and effective tactics to circumvent drug resistance to HSV. This review summarises the current strategies in the development of new targets (the DNA helicase/primase (H/P) complex), new types of molecules (nature products) and new antiviral mechanisms (lethal mutagenesis of Janus-type nucleosides) to fight the drug resistance of HSV. PMID:27025259

  7. Antimicrobial drug resistance ofStaphylococcus aureus in dairy products

    Institute of Scientific and Technical Information of China (English)

    Sasidharan S; Prema B; Yoga Latha L

    2011-01-01

    Objective:To evaluate the prevalence of multidrug resistantStaphylococcus aureus(S. aureus) in dairy products.Methods:Isolation and identification ofS. aureus were performed in3 dairy-based food products. The isolates were tested for their susceptibility to5 different common antimicrobial drugs.Results:Of50 samples examined,5 (10%) were contaminated with S. aureus. Subsequently, the5 isolates were subjected to antimicrobial resistance pattern using five antibiotic discs (methicillin, vancomycin, kanamycin, chloramphenicol and tetracycline). Sample 29 showed resistance to methicillin and vancomycin. Sample18 showed intermediate response to tetracycline. The other samples were susceptible to all the antibiotics tested.Conclusions:The results provide preliminary data on sources of food contamination which may act as vehicles for the transmission of antimicrobial-resistantStaphylococcus.Therefore, it enables us to develop preventive strategies to avoid the emergence of new strains of resistantS. aureus.

  8. Two small molecule lead compounds as new antifungal agents effective against Candida albicans and Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Yones Pilehvar-Soltanahmadi

    2014-06-01

    Full Text Available  Background: Antifungal drug resistance and few numbers of available drugs limit therapeutic options against fungal infections. The present study was designed to discover new antifungal drugs. Materials and Methods: This study was carried out in two separate steps, that is, in silico lead identification and in vitro assaying of antifungal potential. A structural data file of a ternary complex of fusicuccin (legend, C terminus of H+-ATPase and 14-3-3 regulatory protein (1o9F.pdb file was used as a model. Computational screening of a virtual 3D database of drug-like molecules was performed and selected small molecules, resembling the functional part of the ligand performing ligand docking, were tested using ArgusLab (4.0.1. Two lead compounds, 3-Cyclohexan propionic acid (CXP and 4-phenyl butyric acid (PBA were selected according to their ligation scores. Standard Strains of Candida albicans and Saccharomyces cerevisiae were used to measure the antifungal potential of the two identified lead compounds against the fungi using micro-well plate dilution assay. Results: Ligation scores for CXP and PBA were -9.33744 and -10.7259 kcal/mol, respectively, and MIC and MFC of CXP and PBA against the two yeasts were promising. Conclusion: The evidence from the present study suggests that CXP and PBA possess potentially antifungals properties. 

  9. Identification of Ebsulfur Analogues with Broad-Spectrum Antifungal Activity.

    Science.gov (United States)

    Ngo, Huy X; Shrestha, Sanjib K; Garneau-Tsodikova, Sylvie

    2016-07-19

    Invasive fungal infections are on the rise due to an increased population of critically ill patients as a result of HIV infections, chemotherapies, and organ transplantations. Current antifungal drugs are helpful, but are insufficient in addressing the problem of drug-resistant fungal infections. Thus, there is a growing need for novel antimycotics that are safe and effective. The ebselen scaffold has been evaluated in clinical trials and has been shown to be safe in humans. This makes ebselen an attractive scaffold for facile translation from bench to bedside. We recently reported a library of ebselen-inspired ebsulfur analogues with antibacterial properties, but their antifungal activity has not been characterized. In this study, we repurposed ebselen, ebsulfur, and 32 additional ebsulfur analogues as antifungal agents by evaluating their antifungal activity against a panel of 13 clinically relevant fungal strains. The effect of induction of reactive oxygen species (ROS) by three of these compounds was evaluated. Their hemolytic and cytotoxicity activities were also determined using mouse erythrocytes and mammalian cells. The MIC values of these compounds were found to be in the range of 0.02-12.5 μg mL(-1) against the fungal strains tested. Notably, yeast cells treated with our compounds showed an accumulation of ROS, which may further contribute to the growth-inhibitory effect against fungi. This study provides new lead compounds for the development of antimycotic agents. PMID:27334363

  10. Multidrug resistance in oncology and beyond : from imaging of drug efflux pumps to cellular drug targets

    NARCIS (Netherlands)

    Nagengast, Wouter B; Oude Munnink, Thijs H; Dijkers, Eli; Hospers, Geesiena; Brouwers, Adrienne H; Schröder, Carolien P; Lub-de Hooge, Marjolijn; de Vries, Elisabeth G E

    2010-01-01

    Resistance of tumor cells to several structurally unrelated classes of natural products, including anthracyclines, taxanes, and epipodophyllotoxines, is often referred as multidrug resistance (MDR). This is associated with ATP-binding cassette transporters, which function as drug efflux pumps such a

  11. Prediction of resistance development against drug combinations by collateral responses to component drugs

    DEFF Research Database (Denmark)

    Munck, Christian; Gumpert, Heidi; Nilsson Wallin, Annika;

    2014-01-01

    to do so. Thus, predictive models are needed to rationally design resistance-limiting therapeutic regimens. Using adaptive evolution, we studied the resistance response of the common pathogen Escherichia coli to 5 different single antibiotics and all 10 different antibiotic drug pairs. By analyzing...

  12. Drug Resistance and Cancer Stem Cells

    OpenAIRE

    Fonseca, João Pedro Couto

    2012-01-01

    O cancro do pulmão é a principal causa de morte por cancro a nível mundial. Apesar do crescente conhecimento sobre os mecanismos subjacentes ao processo tumorigénico não se tem observado alteração significativa na sobrevivência dos pacientes. É, por isso, urgente encontrar novas estratégias terapêuticas que visem superar a resistência, tanto intrínseca como extrínseca, observada com a quimioterapia corrente. Os tumores são caracterizados pela sua heterogeneidade celular, devido à coexistên...

  13. A new antihypertensive drug ameliorates insulin resistance

    Institute of Scientific and Technical Information of China (English)

    Yan-xia LIU

    2012-01-01

    Insulin resistance (IR)is defined as decreased sensitivity and/or responsiveness to insulin that promote glucose disposal.A growing body of clinical and epidemiologic evidence indicates that essential hypertension and IR often coexist[1].Approximately 50 percent of patients with hypertension can be considered to have IR and hyperinsulinemia[1].This inextricable linkage between hypertension and IR has been identified to increase the prevalence of cardiovascular disease (CVD)and new onset of type Ⅱ diabetes that is the major cause of morbidity and mortality in this clinical syndrome[2].However,the driving force linking IR and hypertension remains to be fully elucidated.

  14. Antifungal susceptibility testing of Candida in the Clinical Laboratory: how to do it, when to do it, and how to interpret it

    Directory of Open Access Journals (Sweden)

    Esther Manso

    2014-06-01

    Full Text Available Significant changes in the management of fungaemia have occurred in the last decade with increased use of fluconazole prophylaxis, of empirical treatment and of echinocandins as first-line agents for documented disease. The emergence of drug resistance in fungal pathogens has a profound impact on human health given limited number of antifungal drugs. Antifungal resistance in Candida may be either intrinsic or acquired and may be encountered in the antifungal drug exposed but also the antifungal drug naïve patient The variation in resistance rates between centers emphasizes that it is essential to have knowledge of the local Candida species distribution and antifungal resistance rates to guide initial therapy for Candida BSI. Moreover, all Candida isolates from blood and normally sterile sites should be identified to the species level. The Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing have developed breakpoints and epidemiological cutoff values that are now established for Candida spp. Clinical microbiology laboratories will be employed commercial susceptibility assays, rather than reference broth microdilution methods and comparative studies are particularly important. Vitek 2®, Etest® and Sensititre YeastOne® provided a high degree of essential agreement and comparable sensitivity and specificity to BMD-RPMI for identifying resistance to azole and echinocandins in Candida spp.

  15. (Post-) Genomic approaches to tackle drug resistance in Leishmania.

    Science.gov (United States)

    Berg, Maya; Mannaert, An; Vanaerschot, Manu; Van Der Auwera, Gert; Dujardin, Jean-Claude

    2013-10-01

    Leishmaniasis, like other neglected diseases is characterized by a small arsenal of drugs for its control. To safeguard the efficacy of current drugs and guide the development of new ones it is thus of utmost importance to acquire a deep understanding of the phenomenon of drug resistance and its link with treatment outcome. We discuss here how (post-)genomic approaches may contribute to this purpose. We highlight the need for a clear definition of the phenotypes under consideration: innate and acquired resistance versus treatment failure. We provide a recent update of our knowledge on the Leishmania genome structure and dynamics, and compare the contribution of targeted and untargeted methods for the understanding of drug resistance and show their limits. We also present the main assays allowing the experimental validation of the genes putatively involved in drug resistance. The importance of analysing information downstream of the genome is stressed and further illustrated by recent metabolomics findings. Finally, the attention is called onto the challenges for implementing the acquired knowledge to the benefit of the patients and the population at risk. PMID:23480865

  16. Multi drug resistance to cancer chemotherapy: Genes involved and blockers

    International Nuclear Information System (INIS)

    During the last three decades, important and considerable research efforts had been performed to investigate the mechanism through which cancer cells overcome the cytotoxic effects of a variety of chemotherapeutic drugs. Most of the previously published work has been focused on the resistance of tumor cells to those anticancer drugs of natural source. Multidrug resistance (MDR) is a cellular cross-resistance to a broad spectrum of natural products used in cancer chemotherapy and is believed to be the major cause of the therapeutic failures of the drugs belonging to different naturally obtained or semisynthetic groups including vinca alkaloids, taxans, epipodophyllotoxins and certain antibiotics. This phenomenon results from overexpression of four MDR genes and their corresponding proteins that act as membrane-bound ATP consuming pumps. These proteins mediate the efflux of many structurally and functionally unrelated anticancer drugs of natural source. MDR may be intrinsic or acquired following exposure to chemotherapy. The existence of intrinsically resistant tumor cell clone before and following chemotherapeutic treatment has been associated with a worse final outcome because of increased incidence of distant metasis. In view of irreplaceability of natural product anticancer drugs as effective chemotherapeutic agents, and in view of MDR as a major obstacle to successful chemotherapy, this review is aimed to highlight the genes involved in MDR, classical MDR blockers and gene therapy approaches to overcome MDR. (author)

  17. Live-cell luciferase assay of drug resistant cells

    OpenAIRE

    sprotocols

    2015-01-01

    To date, multiplexing cell-based assay is essential for high-throughput screening of molecular targets. Measuring multiple parameters of a single sample increases consistency and decrease time and cost of assay. Functional assay of living cell is useful as a first step of multiplexing assay, because live-cell assay allows following second assay using cell lysate or stained cell. However, live-cell assay of drug resistant cells that are highly activated of drug efflux mechanisms is sometimes u...

  18. Treating chromoblastomycosis with systemic antifungals.

    Science.gov (United States)

    Bonifaz, Alexandro; Paredes-Solís, Vanessa; Saúl, Amado

    2004-02-01

    Chromoblastomycosis is a subcutaneous mycosis for which there is no treatment of choice but rather, several treatment options, with low cure rates and many relapses. The choice of treatment should consider several conditions, such as the causal agent (the most common one being Fonsecaea pedrosoi ), extension of the lesions, clinical topography and health status of the patient. Most oral and systemic antifungals have been used; the best results have been obtained with itraconazole and terbinafine at high doses, for a mean of 6 - 12 months. In extensive and refractory cases, chemotherapy with oral antifungals may be associated with thermotherapy (local heat and/or cryosurgery). Limited or early cases may be managed with surgical methods, always associated with oral antifungal agents. It is important to determine the in vitro sensitivity of the major causal agents to the various drugs, by estimating the minimum inhibitory concentration, as well as drug tolerability and drug interactions.

  19. HIV Drug-Resistant Patient Information Management, Analysis, and Interpretation

    OpenAIRE

    Singh, Yashik; Mars, Maurice

    2012-01-01

    Introduction The science of information systems, management, and interpretation plays an important part in the continuity of care of patients. This is becoming more evident in the treatment of human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS), the leading cause of death in sub-Saharan Africa. The high replication rates, selective pressure, and initial infection by resistant strains of HIV infer that drug resistance will inevitably become an important health car...

  20. Antibiotic residues and drug resistance in human intestinal flora.

    OpenAIRE

    Corpet, D. E.

    1987-01-01

    The effect of residual levels of ampicillin on the drug resistance of fecal flora was studied in human volunteers given 1.5 mg of ampicillin orally per day for 21 days. This treatment failed to have any significant reproducible effect on the number of resistant Escherichia coli in their feces. The effect of continuous administration of small doses of ampicillin, chlortetracycline, or streptomycin in the drinking water was studied in gnotobiotic mice inoculated with a human fecal flora. In thi...

  1. Extensively drug-resistant tuberculosis: epidemiology and management

    Directory of Open Access Journals (Sweden)

    Matteelli A

    2014-04-01

    Full Text Available Alberto Matteelli,1 Alberto Roggi,1 Anna CC Carvalho21Institute of Infectious and Tropical Diseases, WHO Collaborating Centre for TB/HIV Co-Infection, University of Brescia, Brescia, Italy; 2Laboratory of Innovations in Therapies, Education and Bioproducts (LITEB, Oswaldo Cruz Institute (IOC, Oswaldo Cruz Foundation (Fiocruz, Rio de Janeiro, BrazilAbstract: The advent of antibiotics for the treatment of tuberculosis (TB represented a major breakthrough in the fight against the disease. However, since its first use, antibiotic therapy has been associated with the emergence of resistance to drugs. The incorrect use of anti-TB drugs, either due to prescription errors, low patient compliance, or poor quality of drugs, led to the widespread emergence of Mycobacterium tuberculosis strains with an expanding spectrum of resistance. The spread of multidrug-resistant (MDR strains (ie, strains resistant to both isoniazid and rifampicin has represented a major threat to TB control since the 1990s. In 2006, the first cases of MDR strains with further resistance to fluoroquinolone and injectable drugs were described and named extensively drug-resistant TB (XDR-TB. The emergence of XDR-TB strains is a result of mismanagement of MDR cases, and treatment relies on drugs that are less potent and more toxic than those used to treat drug-susceptible or MDR strains. Furthermore, treatment success is lower and mortality higher than achieved in MDR-TB cases, and the number of drugs necessary in the intensive phase of treatment may be higher than the four drugs recommended for MDR-TB. Linezolid may represent a valuable drug to treat cases of XDR-TB. Delamanid, bedaquiline, and PA-824 are new anti-TB agents in the development pipeline that have the potential to enhance the cure rate of XDR-TB. The best measures to prevent new cases of XDR-TB are the correct management of MDR-TB patients, early detection, and proper treatment of existing patients with XDR

  2. Effect and Safety of Shihogyejitang for Drug Resistant Childhood Epilepsy.

    Science.gov (United States)

    Lee, Jinsoo; Son, Kwanghyun; Hwang, Gwiseo; Kim, Moonju

    2016-01-01

    Objective. Herbal medicine has been widely used to treat drug resistant epilepsy. Shihogyejitang (SGT) has been commonly used to treat epilepsy. We investigated the effect and safety of SGT in children with drug resistant epilepsy. Design. We reviewed medical records of 54 patients with epilepsy, who failed to respond to at least two antiepileptic drugs and have been treated with SGT between April 2006 and June 2014 at the Department of Pediatric Neurology, I-Tomato Hospital, Korea. Effect was measured by the response rate, seizure-free rate, and retention rate at six months. We also checked adverse events, change in antiepileptic drugs use, and the variables related to the outcome. Results. Intent-to-treat analysis showed that, after six months, 44.4% showed a >50% seizure reduction, 24.1% including seizure-free, respectively, and 53.7% remained on SGT. Two adverse events were reported, mild skin rash and fever. Focal seizure type presented significantly more positive responses when compared with other seizure types at six months (p = 0.0284, Fisher's exact test). Conclusion. SGT is an effective treatment with excellent tolerability for drug resistant epilepsy patients. Our data provide evidence that SGT may be used as alternative treatment option when antiepileptic drug does not work in epilepsy children. PMID:27047568

  3. Effect and Safety of Shihogyejitang for Drug Resistant Childhood Epilepsy

    Directory of Open Access Journals (Sweden)

    Jinsoo Lee

    2016-01-01

    Full Text Available Objective. Herbal medicine has been widely used to treat drug resistant epilepsy. Shihogyejitang (SGT has been commonly used to treat epilepsy. We investigated the effect and safety of SGT in children with drug resistant epilepsy. Design. We reviewed medical records of 54 patients with epilepsy, who failed to respond to at least two antiepileptic drugs and have been treated with SGT between April 2006 and June 2014 at the Department of Pediatric Neurology, I-Tomato Hospital, Korea. Effect was measured by the response rate, seizure-free rate, and retention rate at six months. We also checked adverse events, change in antiepileptic drugs use, and the variables related to the outcome. Results. Intent-to-treat analysis showed that, after six months, 44.4% showed a >50% seizure reduction, 24.1% including seizure-free, respectively, and 53.7% remained on SGT. Two adverse events were reported, mild skin rash and fever. Focal seizure type presented significantly more positive responses when compared with other seizure types at six months (p=0.0284, Fisher’s exact test. Conclusion. SGT is an effective treatment with excellent tolerability for drug resistant epilepsy patients. Our data provide evidence that SGT may be used as alternative treatment option when antiepileptic drug does not work in epilepsy children.

  4. Determinants of Genetic Diversity of Spontaneous Drug Resistance in Bacteria.

    Science.gov (United States)

    Couce, Alejandro; Rodríguez-Rojas, Alexandro; Blázquez, Jesús

    2016-07-01

    Any pathogen population sufficiently large is expected to harbor spontaneous drug-resistant mutants, often responsible for disease relapse after antibiotic therapy. It is seldom appreciated, however, that while larger populations harbor more mutants, the abundance distribution of these mutants is expected to be markedly uneven. This is because a larger population size allows early mutants to expand for longer, exacerbating their predominance in the final mutant subpopulation. Here, we investigate the extent to which this reduction in evenness can constrain the genetic diversity of spontaneous drug resistance in bacteria. Combining theory and experiments, we show that even small variations in growth rate between resistant mutants and the wild type result in orders-of-magnitude differences in genetic diversity. Indeed, only a slight fitness advantage for the mutant is enough to keep diversity low and independent of population size. These results have important clinical implications. Genetic diversity at antibiotic resistance loci can determine a population's capacity to cope with future challenges (i.e., second-line therapy). We thus revealed an unanticipated way in which the fitness effects of antibiotic resistance can affect the evolvability of pathogens surviving a drug-induced bottleneck. This insight will assist in the fight against multidrug-resistant microbes, as well as contribute to theories aimed at predicting cancer evolution.

  5. Evidence for epistatic interactions in antiepileptic drug resistance.

    Science.gov (United States)

    Kim, Myeong-Kyu; Moore, Jason H; Kim, Jong-Ki; Cho, Ki-Hyun; Cho, Yong-Won; Kim, Yo-Sik; Lee, Min-Cheol; Kim, Young-Ok; Shin, Min-Ho

    2011-01-01

    To investigate the epistatic interactions involved in antiepileptic drug (AED) resistance, 26 coding single-nucleotide polymorphisms (SNPs) were selected from 16 candidate genes. A total of 200 patients with drug-resistant localization-related epilepsy and 200 patients with drug-responsive localization-related epilepsy were genotyped individually for the SNPs. Rather than using the traditional parametric statistical method, a new statistical method, multifactor dimensionality reduction (MDR), was used to determine whether gene-gene interactions increase the risk of AED resistance. The MDR method indicated that a combination of four SNPs (rs12658835 and rs35166395 from GABRA1, rs2228622 from EAAT3 and rs2304725 from GAT3) was the best model for predicting susceptibility to AED resistance with a statistically significant testing accuracy of 0.625 (P < 0.001) and cross-validation consistency of 10/10. This best model had an odds ratio of 3.68 with a significant 95% confidence interval of 2.32-5.85 (P < 0.0001). Our results may provide meaningful information on the mechanism underlying AED resistance and, to the best of our knowledge, this is the first report of evidence for gene-gene interactions underlying AED resistance. PMID:21124337

  6. Scedosporium apiospermum infections and the role of combination antifungal therapy and GM-CSF: A case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Chloe Goldman

    2016-03-01

    Full Text Available Scedosporium apiospermum, a ubiquitous environmental mold, is increasingly reported as causing invasive fungal disease in immunocompromised hosts. It poses a therapeutic challenge due to its intrinsic resistance to traditional antifungals and ability to recur despite demonstrating susceptibility. We present an immunocompromised patient with a cutaneous S. apiospermum infection that disseminated despite treatment with voriconazole, the drug of choice. Adding echinocandins and GM-CSF provided partial recovery, indicating a potential synergistic role of dual-antifungal and immunotherapeutic agents.

  7. Controlled nail delivery of a novel lipophilic antifungal agent using various modern drug carrier systems as well as in vitro and ex vivo model systems.

    Science.gov (United States)

    Naumann, Sandy; Meyer, Jean-Philippe; Kiesow, Andreas; Mrestani, Yahya; Wohlrab, Johannes; Neubert, Reinhard H H

    2014-04-28

    The penetration behavior into human nails and animal hoof membranes of a novel antifungal agent (EV-086K) for the treatment of onychomycosis was investigated in this study. The new drug provides a high lipophilicity which is adverse for penetration into nails. Therefore, four different formulations were developed, with particular focus on a colloidal carrier system (CCS) due to its penetration enhancing properties. On the one hand, ex vivo penetration experiments on human nails were performed. Afterwards the human nail plates were cut by cryomicrotome in order to quantify the drug concentration in the dorsal, intermediate and ventral nail layer using high-performance liquid chromatography (HPLC) with UV detection. On the other hand, equine and bovine hoof membranes were used to determine the in vitro penetration of the drug into the acceptor compartment of an online diffusion cell coupled with Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy. In combination, both results should exhibit a correlation between the EV-086K penetration behavior in human nail plates and animal hoof membranes. The investigations showed that the developed CCS could increase drug delivery through the human nail most compared to other formulations (nail lacquer, solution and hydrogel). Using animal hooves in the online diffusion cell, we were able to calculate pharmacokinetic data of the penetration process, especially diffusion and permeability coefficients. Finally, a qualitative correlation between the penetration results of human nails and equine hooves was established. PMID:24560884

  8. Controlled nail delivery of a novel lipophilic antifungal agent using various modern drug carrier systems as well as in vitro and ex vivo model systems.

    Science.gov (United States)

    Naumann, Sandy; Meyer, Jean-Philippe; Kiesow, Andreas; Mrestani, Yahya; Wohlrab, Johannes; Neubert, Reinhard H H

    2014-04-28

    The penetration behavior into human nails and animal hoof membranes of a novel antifungal agent (EV-086K) for the treatment of onychomycosis was investigated in this study. The new drug provides a high lipophilicity which is adverse for penetration into nails. Therefore, four different formulations were developed, with particular focus on a colloidal carrier system (CCS) due to its penetration enhancing properties. On the one hand, ex vivo penetration experiments on human nails were performed. Afterwards the human nail plates were cut by cryomicrotome in order to quantify the drug concentration in the dorsal, intermediate and ventral nail layer using high-performance liquid chromatography (HPLC) with UV detection. On the other hand, equine and bovine hoof membranes were used to determine the in vitro penetration of the drug into the acceptor compartment of an online diffusion cell coupled with Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy. In combination, both results should exhibit a correlation between the EV-086K penetration behavior in human nail plates and animal hoof membranes. The investigations showed that the developed CCS could increase drug delivery through the human nail most compared to other formulations (nail lacquer, solution and hydrogel). Using animal hooves in the online diffusion cell, we were able to calculate pharmacokinetic data of the penetration process, especially diffusion and permeability coefficients. Finally, a qualitative correlation between the penetration results of human nails and equine hooves was established.

  9. Hepatitis C Virus and Antiviral Drug Resistance

    Science.gov (United States)

    Kim, Seungtaek; Han, Kwang-Hyub; Ahn, Sang Hoon

    2016-01-01

    Since its discovery in 1989, hepatitis C virus (HCV) has been intensively investigated to understand its biology and develop effective antiviral therapies. The efforts of the previous 25 years have resulted in a better understanding of the virus, and this was facilitated by the development of in vitro cell culture systems for HCV replication. Antiviral treatments and sustained virological responses have also improved from the early interferon monotherapy to the current all-oral regimens using direct-acting antivirals. However, antiviral resistance has become a critical issue in the treatment of chronic hepatitis C, similar to other chronic viral infections, and retreatment options following treatment failure have become important questions. Despite the clinical challenges in the management of chronic hepatitis C, substantial progress has been made in understanding HCV, which may facilitate the investigation of other closely related flaviviruses and lead to the development of antiviral agents against these human pathogens. PMID:27784846

  10. Additional drug resistance of multidrug-resistant tuberculosis in patients in 9 countries.

    Science.gov (United States)

    Kurbatova, Ekaterina V; Dalton, Tracy; Ershova, Julia; Tupasi, Thelma; Caoili, Janice Campos; Van Der Walt, Martie; Kvasnovsky, Charlotte; Yagui, Martin; Bayona, Jaime; Contreras, Carmen; Leimane, Vaira; Via, Laura E; Kim, HeeJin; Akksilp, Somsak; Kazennyy, Boris Y; Volchenkov, Grigory V; Jou, Ruwen; Kliiman, Kai; Demikhova, Olga V; Cegielski, J Peter

    2015-06-01

    Data from a large multicenter observational study of patients with multidrug-resistant tuberculosis (MDR TB) were analyzed to simulate the possible use of 2 new approaches to treatment of MDR TB: a short (9-month) regimen and a bedaquiline-containing regimen. Of 1,254 patients, 952 (75.9%) had no resistance to fluoroquinolones and second-line injectable drugs and thus would qualify as candidates for the 9-month regimen; 302 (24.1%) patients with resistance to a fluoroquinolone or second-line injectable drug would qualify as candidates for a bedaquiline-containing regimen in accordance with published guidelines. Among candidates for the 9-month regimen, standardized drug-susceptibility tests demonstrated susceptibility to a median of 5 (interquartile range 5-6) drugs. Among candidates for bedaquiline, drug-susceptibility tests demonstrated susceptibility to a median of 3 (interquartile range 2-4) drugs; 26% retained susceptibility to <2 drugs. These data may assist national TB programs in planning to implement new drugs and drug regimens. PMID:25988299

  11. Biophysical principles predict fitness landscapes of drug resistance.

    Science.gov (United States)

    Rodrigues, João V; Bershtein, Shimon; Li, Anna; Lozovsky, Elena R; Hartl, Daniel L; Shakhnovich, Eugene I

    2016-03-15

    Fitness landscapes of drug resistance constitute powerful tools to elucidate mutational pathways of antibiotic escape. Here, we developed a predictive biophysics-based fitness landscape of trimethoprim (TMP) resistance for Escherichia coli dihydrofolate reductase (DHFR). We investigated the activity, binding, folding stability, and intracellular abundance for a complete set of combinatorial DHFR mutants made out of three key resistance mutations and extended this analysis to DHFR originated from Chlamydia muridarum and Listeria grayi We found that the acquisition of TMP resistance via decreased drug affinity is limited by a trade-off in catalytic efficiency. Protein stability is concurrently affected by the resistant mutants, which precludes a precise description of fitness from a single molecular trait. Application of the kinetic flux theory provided an accurate model to predict resistance phenotypes (IC50) quantitatively from a unique combination of the in vitro protein molecular properties. Further, we found that a controlled modulation of the GroEL/ES chaperonins and Lon protease levels affects the intracellular steady-state concentration of DHFR in a mutation-specific manner, whereas IC50 is changed proportionally, as indeed predicted by the model. This unveils a molecular rationale for the pleiotropic role of the protein quality control machinery on the evolution of antibiotic resistance, which, as we illustrate here, may drastically confound the evolutionary outcome. These results provide a comprehensive quantitative genotype-phenotype map for the essential enzyme that serves as an important target of antibiotic and anticancer therapies.

  12. Biophysical principles predict fitness landscapes of drug resistance.

    Science.gov (United States)

    Rodrigues, João V; Bershtein, Shimon; Li, Anna; Lozovsky, Elena R; Hartl, Daniel L; Shakhnovich, Eugene I

    2016-03-15

    Fitness landscapes of drug resistance constitute powerful tools to elucidate mutational pathways of antibiotic escape. Here, we developed a predictive biophysics-based fitness landscape of trimethoprim (TMP) resistance for Escherichia coli dihydrofolate reductase (DHFR). We investigated the activity, binding, folding stability, and intracellular abundance for a complete set of combinatorial DHFR mutants made out of three key resistance mutations and extended this analysis to DHFR originated from Chlamydia muridarum and Listeria grayi We found that the acquisition of TMP resistance via decreased drug affinity is limited by a trade-off in catalytic efficiency. Protein stability is concurrently affected by the resistant mutants, which precludes a precise description of fitness from a single molecular trait. Application of the kinetic flux theory provided an accurate model to predict resistance phenotypes (IC50) quantitatively from a unique combination of the in vitro protein molecular properties. Further, we found that a controlled modulation of the GroEL/ES chaperonins and Lon protease levels affects the intracellular steady-state concentration of DHFR in a mutation-specific manner, whereas IC50 is changed proportionally, as indeed predicted by the model. This unveils a molecular rationale for the pleiotropic role of the protein quality control machinery on the evolution of antibiotic resistance, which, as we illustrate here, may drastically confound the evolutionary outcome. These results provide a comprehensive quantitative genotype-phenotype map for the essential enzyme that serves as an important target of antibiotic and anticancer therapies. PMID:26929328

  13. "Applied" Aspects of the Drug Resistance Strategies Project

    Science.gov (United States)

    Hecht, Michael L.; Miller-Day, Michelle A.

    2010-01-01

    This paper discusses the applied aspects of our Drug Resistance Strategies Project. We argue that a new definitional distinction is needed to expand the notion of "applied" from the traditional notion of utilizing theory, which we call "applied.1," in order to consider theory-grounded, theory testing and theory developing applied research. We…

  14. P-Glycoprotein and Drug Resistance in Systemic Autoimmune Diseases

    Directory of Open Access Journals (Sweden)

    Andrea Picchianti-Diamanti

    2014-03-01

    Full Text Available Autoimmune diseases such as systemic lupus erythematosus (SLE, rheumatoid arthritis (RA and psoriatic arthritis (PsA are chronic inflammatory disorders of unknown etiology characterized by a wide range of abnormalities of the immune system that may compromise the function of several organs, such as kidney, heart, joints, brain and skin. Corticosteroids (CCS, synthetic and biologic immunosuppressive agents have demonstrated the capacity to improve the course of autoimmune diseases. However, a significant number of patients do not respond or develop resistance to these therapies over time. P-glycoprotein (P-gp is a transmembrane protein that pumps several drugs out of the cell, including CCS and immunosuppressants; thus, its over-expression or hyper-function has been proposed as a possible mechanism of drug resistance in patients with autoimmune disorders. Recently, different authors have demonstrated that P-gp inhibitors, such as cyclosporine A (CsA and its analogue Tacrolimus, are able to reduce P-gp expression and or function in SLE, RA and PsA patients. These observations suggest that P-gp antagonists could be adopted to revert drug resistance and improve disease outcome. The complex inter-relationship among drug resistance, P-gp expression and autoimmunity still remains elusive.

  15. Flu Resistance to Antiviral Drug in North Carolina

    Centers for Disease Control (CDC) Podcasts

    2011-12-19

    Dr. Katrina Sleeman, Associate Service Fellow at CDC, discusses resistance to an antiviral flu drug in North Carolina.  Created: 12/19/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 12/19/2011.

  16. Leukemia stem cells in drug resistance and metastasis

    Institute of Scientific and Technical Information of China (English)

    DENG Chao-hua; ZHANG Qiu-ping

    2010-01-01

    Objective To review the central role of leukemia stem cells (LSCs) in drug resistance and metastasis, aiming to provide key insights into leukemogenic pathology and developing novel therapeutic strategies against the relapse of leukemia.Data sources The data used in this review were obtained mainly from the studies reported in PubMed using the key terms "tumor-initiating cells", "leukemia stem cells", "drug resistance" and "metastasis".Study selection Relevant articles on studies of leukemia stem cells were selected.Results Increasing numbers of studies have suggested the importance of cancer stem cells (CSCs) in the initiation and maintenance of cancer, especially in leukemia. This review has summarized the origin, characteristics, isolation and identification of LSCs. It highlights the crucial role of LSCs in drug resistance and metastasis of leukemia by illustrating possible mechanisms and aims to provide novel therapeutic strategies for LSCs-targeted treatment.Conclusion LSCs play a crucial role in drug resistance and metastasis of leukemia and new promising LSCs-targeted therapies warrant investigation in both experimental models and clinical practice.

  17. Characterization of Tamoxifen as an Antifungal Agent Using the Yeast Schizosaccharomyces Pombe Model Organism.

    Science.gov (United States)

    Zhang, Xibo; Fang, Yue; Jaiseng, Wurentuya; Hu, Lingling; Lu, Yabin; Ma, Yan; Furuyashiki, Tomoyuki

    2015-01-01

    Tamoxifen, a selective estrogen receptor modulator used for managing breast cancer, is known to have antifungal activity. However, its molecular mechanism remains unknown. Using the fission yeast Schizosaccharomyces pombe as a model organism, we have explored the mechanism involved in antifungal action of tamoxifen. Since tamoxifen was shown to inhibit the binding of calmodulin to calcineurin in fungi, we first examined involvement of these molecules and found that overexpression of a catalytic subunit of calcineurin and its constitutively active mutant as well as calmodulin increases tamoxifen sensitivity. Since terbinafine and azoles inhibit enzymes for ergosterol biosynthesis, Erg1 and Erg11, for their antifungal actions, we also examined involvement of these molecules. Overexpression of Erg1 and Erg11 reduced the sensitivity to terbinafine and azoles, respectively, but increased tamoxifen sensitivity, suggesting that ergosterol biosynthesis is differently related to the action of tamoxifen and those of terbinafine and azoles. To elucidate molecules involved in tamoxifen action, we performed a genome-wide screen for altered sensitivity to tamoxifen using a fission yeast gene deletion library, and identified various hypersensitive and resistant mutants to this drug. Notably, these mutants are rarely overlapped with those identified in similar genetic screens with currently used antifungals, suggesting a novel mode of antifungal action. Furthermore, tamoxifen augmented antifungal actions of terbinafine and azoles, suggesting synergetic actions between these drugs. Therefore, our findings suggest that calmodulin-calcineurin pathway and ergosterol biosynthesis are related to antifungal action of tamoxifen, and propose novel targets for antifungal development as well as combined therapy with tamoxifen for fungal diseases. PMID:26628015

  18. Drug Resistance Characteristics and Macrolide-Resistant Mechanisms of Streptococcus pneumoniae in Wenzhou City, China.

    Science.gov (United States)

    Hu, Dakang; Sun, Zheng; Luo, Xinhua; Liu, Shuangchun; Yu, Lianhua; Qu, Ying; Yang, Jinhong; Yu, Jian; Li, Xiangyang; Zhang, Jin

    2016-01-01

    BACKGROUND Streptococcus pneumoniae (SP) is a Gram-positive, alpha-hemolytic, facultative anaerobic member of the genus Streptococcus. The erythromycin-resistant methylase (erm) gene and macrolide efflux (mef) gene are the 2 main genes that can mediate SP. Transposon (Tn) also plays an important role in the collection and metastasis of the gene. In the present study we investigated the drug resistance characteristics and the macrolide-resistant mechanisms of SP in Wenzhou City, China. MATERIAL AND METHODS Sixty-eight strains of SP were isolated from sputum samples of hospitalized children in the Second Affiliated Hospital of Wenzhou Medical University. These strains were analyzed using antimicrobial susceptibility tests to determine their drug resistance to 10 kinds of antibacterials. Macrolide-resistant phenotypes were identified using K-B method. PCR method was used to analyze the erm B gene, mef A gene, and int Tn gene. RESULTS Drug resistance rates of 68 strains of SP were 98.5%, 100.0%, 63.2%, 52.9%, 94.1%, 89.7%, 0.0%, 0.0%, 16.2%, and 14.7% for clindamycin, erythromycin, penicillin G, cefotaxime, tetracycline, sulfamethoxazole/trimethoprim, levofloxacin, vancomycin, chloramphenicol, and amoxicillin, respectively. Total detection rates of the erm B gene, mef A gene, and int Tn gene were 98.5%, 91.2%, and 100.0%, respectively. CONCLUSIONS SP shows significant multi-drug resistance in Wenzhou City, whereas there is no clinical value of macrolides antibiotics for SP. cMLSB mediated by erm B gene is the most predominant phenotype among macrolide-resistant SP. The int Tn gene may play an important role in horizontal transfer and clonal dissemination of SP drug resistance genes in Wenzhou City. PMID:27483416

  19. Posaconazole exhibits in vitro and in vivo synergistic antifungal activity with caspofungin or FK506 against Candida albicans.

    Directory of Open Access Journals (Sweden)

    Ying-Lien Chen

    Full Text Available The object of this study was to test whether posaconazole, a broad-spectrum antifungal agent inhibiting ergosterol biosynthesis, exhibits synergy with the β-1,3 glucan synthase inhibitor caspofungin or the calcineurin inhibitor FK506 against the human fungal pathogen Candida albicans. Although current drug treatments for Candida infection are often efficacious, the available antifungal armamentarium may not be keeping pace with the increasing incidence of drug resistant strains. The development of drug combinations or novel antifungal drugs to address emerging drug resistance is therefore of general importance. Combination drug therapies are employed to treat patients with HIV, cancer, or tuberculosis, and has considerable promise in the treatment of fungal infections like cryptococcal meningitis and C. albicans infections. Our studies reported here demonstrate that posaconazole exhibits in vitro synergy with caspofungin or FK506 against drug susceptible or resistant C. albicans strains. Furthermore, these combinations also show in vivo synergy against C. albicans strain SC5314 and its derived echinocandin-resistant mutants, which harbor an S645Y mutation in the CaFks1 β-1,3 glucan synthase drug target, suggesting potential therapeutic applicability for these combinations in the future.

  20. Amino Acid Substitutions in the Cytochrome P-450 Lanosterol 14α-Demethylase (CYP51A1) from Azole-Resistant Candida albicans Clinical Isolates Contribute to Resistance to Azole Antifungal Agents

    OpenAIRE

    Sanglard, Dominique; Ischer, Françoise; Koymans, Luc; Bille, Jacques

    1998-01-01

    The cytochrome P-450 lanosterol 14α-demethylase (CYP51A1) of yeasts is involved in an important step in the biosynthesis of ergosterol. Since CYP51A1 is the target of azole antifungal agents, this enzyme is potentially prone to alterations leading to resistance to these agents. Among them, a decrease in the affinity of CYP51A1 for these agents is possible. We showed in a group of Candida albicans isolates from AIDS patients that multidrug efflux transporters were playing an important role in ...

  1. Clinically relevant transmitted drug resistance to first line antiretroviral drugs and implications for recommendations.

    Directory of Open Access Journals (Sweden)

    Susana Monge

    Full Text Available BACKGROUND: The aim was to analyse trends in clinically relevant resistance to first-line antiretroviral drugs in Spain, applying the Stanford algorithm, and to compare these results with reported Transmitted Drug Resistance (TDR defined by the 2009 update of the WHO SDRM list. METHODS: We analysed 2781 sequences from ARV naive patients of the CoRIS cohort (Spain between 2007-2011. Using the Stanford algorithm "Low-level resistance", "Intermediate resistance" and "High-level resistance" categories were considered as "Resistant". RESULTS: 70% of the TDR found using the WHO list were relevant for first-line treatment according to the Stanford algorithm. A total of 188 patients showed clinically relevant resistance to first-line ARVs [6.8% (95%Confidence Interval: 5.8-7.7], and 221 harbored TDR using the WHO list [7.9% (6.9-9.0]. Differences were due to a lower prevalence in clinically relevant resistance for NRTIs [2.3% (1.8-2.9 vs. 3.6% (2.9-4.3 by the WHO list] and PIs [0.8% (0.4-1.1 vs. 1.7% (1.2-2.2], while it was higher for NNRTIs [4.6% (3.8-5.3 vs. 3.7% (3.0-4.7]. While TDR remained stable throughout the study period, clinically relevant resistance to first line drugs showed a significant trend to a decline (p = 0.02. CONCLUSIONS: Prevalence of clinically relevant resistance to first line ARVs in Spain is decreasing, and lower than the one expected looking at TDR using the WHO list. Resistance to first-line PIs falls below 1%, so the recommendation of screening for TDR in the protease gene should be questioned in our setting. Cost-effectiveness studies need to be carried out to inform evidence-based recommendations.

  2. Balancing drug resistance and growth rates via compensatory mutations in the Plasmodium falciparum chloroquine resistance transporter.

    Science.gov (United States)

    Petersen, Ines; Gabryszewski, Stanislaw J; Johnston, Geoffrey L; Dhingra, Satish K; Ecker, Andrea; Lewis, Rebecca E; de Almeida, Mariana Justino; Straimer, Judith; Henrich, Philipp P; Palatulan, Eugene; Johnson, David J; Coburn-Flynn, Olivia; Sanchez, Cecilia; Lehane, Adele M; Lanzer, Michael; Fidock, David A

    2015-07-01

    The widespread use of chloroquine to treat Plasmodium falciparum infections has resulted in the selection and dissemination of variant haplotypes of the primary resistance determinant PfCRT. These haplotypes have encountered drug pressure and within-host competition with wild-type drug-sensitive parasites. To examine these selective forces in vitro, we genetically engineered P. falciparum to express geographically diverse PfCRT haplotypes. Variant alleles from the Philippines (PH1 and PH2, which differ solely by the C72S mutation) both conferred a moderate gain of chloroquine resistance and a reduction in growth rates in vitro. Of the two, PH2 showed higher IC50 values, contrasting with reduced growth. Furthermore, a highly mutated pfcrt allele from Cambodia (Cam734) conferred moderate chloroquine resistance and enhanced growth rates, when tested against wild-type pfcrt in co-culture competition assays. These three alleles mediated cross-resistance to amodiaquine, an antimalarial drug widely used in Africa. Each allele, along with the globally prevalent Dd2 and 7G8 alleles, rendered parasites more susceptible to lumefantrine, the partner drug used in the leading first-line artemisinin-based combination therapy. These data reveal ongoing region-specific evolution of PfCRT that impacts drug susceptibility and relative fitness in settings of mixed infections, and raise important considerations about optimal agents to treat chloroquine-resistant malaria.

  3. Antifungal Susceptibility Testing of Ascomycetous Yeasts Isolated from Animals.

    Science.gov (United States)

    Álvarez-Pérez, Sergio; García, Marta E; Peláez, Teresa; Martínez-Nevado, Eva; Blanco, José L

    2016-08-01

    Recent studies suggest that antifungal resistance in yeast isolates of veterinary origin may be an underdiagnosed threat. We tested a collection of 92 ascomycetous yeast isolates that were obtained in Spain from birds, mammals and insects for antifungal susceptibility. MICs to amphotericin B and azoles were low, and no resistant isolates were detected. Despite these results, and given the potential role of animals as reservoirs of resistant strains, continuous monitoring of antifungal susceptibility in the veterinary setting is recommended. PMID:27216048

  4. Characterization of Antifungal Activity and Nail Penetration of ME1111, a New Antifungal Agent for Topical Treatment of Onychomycosis

    OpenAIRE

    Tabata, Yuji; Takei-Masuda, Naomi; Kubota, Natsuki; Takahata, Sho; Ohyama, Makoto; Kaneda, Kaori; Iida, Maiko; Maebashi, Kazunori

    2016-01-01

    Fungal nail infection (onychomycosis) is a prevalent disease in many areas of the world, with a high incidence approaching 23%. Available antifungals to treat the disease suffer from a number of disadvantages, necessitating the discovery of new efficacious and safe antifungals. Here, we evaluate the in vitro antifungal activity and nail penetration ability of ME1111, a novel antifungal agent, along with comparator drugs, including ciclopirox, amorolfine, terbinafine, and itraconazole. ME1111 ...

  5. The population genetics of drug resistance evolution in natural populations of viral, bacterial and eukaryotic pathogens.

    Science.gov (United States)

    Wilson, Benjamin A; Garud, Nandita R; Feder, Alison F; Assaf, Zoe J; Pennings, Pleuni S

    2016-01-01

    Drug resistance is a costly consequence of pathogen evolution and a major concern in public health. In this review, we show how population genetics can be used to study the evolution of drug resistance and also how drug resistance evolution is informative as an evolutionary model system. We highlight five examples from diverse organisms with particular focus on: (i) identifying drug resistance loci in the malaria parasite Plasmodium falciparum using the genomic signatures of selective sweeps, (ii) determining the role of epistasis in drug resistance evolution in influenza, (iii) quantifying the role of standing genetic variation in the evolution of drug resistance in HIV, (iv) using drug resistance mutations to study clonal interference dynamics in tuberculosis and (v) analysing the population structure of the core and accessory genome of Staphylococcus aureus to understand the spread of methicillin resistance. Throughout this review, we discuss the uses of sequence data and population genetic theory in studying the evolution of drug resistance.

  6. Smart doxorubicin nanoparticles with high drug payload for enhanced chemotherapy against drug resistance and cancer diagnosis

    Science.gov (United States)

    Yu, Caitong; Zhou, Mengjiao; Zhang, Xiujuan; Wei, Weijia; Chen, Xianfeng; Zhang, Xiaohong

    2015-03-01

    Considering the obvious advantages in efficacy and price, doxorubicin (DOX) has been widely used for a range of cancers, which is usually encapsulated in various nanocarriers for drug delivery. Although effective, in most nanocarrier-based delivery systems, the drug loading capacity of DOX is rather low; this can lead to undesired systemic toxicity and excretion concern. Herein, we report for the first time the usage of pure doxorubicin nanoparticles (DOX NPs) without addition of any carriers for enhanced chemotherapy against drug-resistance. The drug payload reaches as high as 90.47%, which largely surpassed those in previous reports. These PEG stabilized DOX NPs exhibit good biocompatibility and stability, long blood circulation time, fast release in an acidic environment and high accumulation in tumors. Compared with free DOX, DOX NPs display a dramatically enhanced anticancer therapeutic efficacy in the inhibition of cell and tumor growth. Moreover, they can also be readily incorporated with other anticancer drugs for synergistic chemotherapy to overcome the drug resistance of cancers. The fluorescence properties of DOX also endow these NPs with imaging capabilities, thus making it a multifunctional system for diagnosis and treatment. This work demonstrates great potential of DOX NPs for cancer diagnosis, therapy and overcoming drug tolerance.Considering the obvious advantages in efficacy and price, doxorubicin (DOX) has been widely used for a range of cancers, which is usually encapsulated in various nanocarriers for drug delivery. Although effective, in most nanocarrier-based delivery systems, the drug loading capacity of DOX is rather low; this can lead to undesired systemic toxicity and excretion concern. Herein, we report for the first time the usage of pure doxorubicin nanoparticles (DOX NPs) without addition of any carriers for enhanced chemotherapy against drug-resistance. The drug payload reaches as high as 90.47%, which largely surpassed those in

  7. Drug resistance of bacteria——present situation and treatment

    Directory of Open Access Journals (Sweden)

    Min ZHAO

    2011-02-01

    Full Text Available Antimicrobial resistance of bacteria is a serious problem worldwide.It has become the difficulty of anti-infection that multidrug-resistance(MDR and drug wide-resistance(DWR gram-negative bacteria are increasing year and year.Alarm has been knolled again on the emerging of Gram-negative pathogens producing the NDM-1 worldwide in 2010.NDM-1 is a new metallo-carbapenemase which is highly resistant to all antibiotics,and has been mostly found among Escherichia coli and Klebsiella pneumoniae.Infections of MDR and DWR Enterobacteriaceae can be effectively treated with tigecycline,polymyxin and fosfomycin on clinic trail.Prevention is very important for reducing the occurring and spreading of MDR and DWR bacteria.

  8. Antimalarial drug resistance in Bangladesh, 1996-2012.

    Science.gov (United States)

    Haque, Ubydul; Glass, Gregory E; Haque, Waziul; Islam, Nazrul; Roy, Shyamal; Karim, Jahirul; Noedl, Harald

    2013-12-01

    Malaria remains an important health problem in Bangladesh, with approximately 14 million people at risk. Antimalarial drug resistance is a major obstacle to the control of malaria in endemic countries. In 2012, Bangladesh reported an estimated 29 522 malaria episodes, of which 94% were reported as being caused by Plasmodium falciparum. In this study, we reviewed and summarized antimalarial drug resistance data from Bangladesh published until June 2013. We searched published sources for data referring to any type of P. falciparum drug resistance (in vivo, in vitro, or molecular) and found 169 articles published in peer-reviewed journals. Of these, 143 articles were excluded because they did not meet our inclusion criteria. After detailed review of the remaining 26 articles, 14 were selected for evaluation. Published studies indicate that P. falciparum shows varying levels of resistance to chloroquine, mefloquine and sulfadoxine-pyrimethamine. Combination therapy of chloroquine and primaquine has proven ineffective and combinations of sulfadoxine-pyrimethamine with either quinine or chloroquine have also shown poor efficacy. Recent studies indicate that artemisinin derivatives, such as artesunate, remain highly efficacious in treating P. falciparum malaria. Available data suggest that artemisinins, quinine, doxycyline, mefloquine-artesunate and azithromycin-artesunate combination therapy remain efficacious in the treatment of P. falciparum malaria in Bangladesh.

  9. Modeling HIV-1 drug resistance as episodic directional selection.

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    Ben Murrell

    Full Text Available The evolution of substitutions conferring drug resistance to HIV-1 is both episodic, occurring when patients are on antiretroviral therapy, and strongly directional, with site-specific resistant residues increasing in frequency over time. While methods exist to detect episodic diversifying selection and continuous directional selection, no evolutionary model combining these two properties has been proposed. We present two models of episodic directional selection (MEDS and EDEPS which allow the a priori specification of lineages expected to have undergone directional selection. The models infer the sites and target residues that were likely subject to directional selection, using either codon or protein sequences. Compared to its null model of episodic diversifying selection, MEDS provides a superior fit to most sites known to be involved in drug resistance, and neither one test for episodic diversifying selection nor another for constant directional selection are able to detect as many true positives as MEDS and EDEPS while maintaining acceptable levels of false positives. This suggests that episodic directional selection is a better description of the process driving the evolution of drug resistance.

  10. Experience with pulmonary resection for extensively drug-resistant tuberculosis.

    Science.gov (United States)

    Shiraishi, Yuji; Katsuragi, Naoya; Kita, Hidefumi; Toishi, Masayuki; Onda, Takahito

    2008-12-01

    Extensively drug-resistant tuberculosis is becoming a global threat. It is a relatively new phenomenon, and its optimal management remains undetermined. We report our experience in using pulmonary resection for treating patients with this disease. Records were reviewed of 54 consecutive patients undergoing a pulmonary resection for multidrug-resistant tuberculosis at Fukujuji Hospital between 2000 and 2006. These patients were identified using the definition approved by the World Health Organization Global Task Force on extensively drug-resistant tuberculosis in October 2006. Five (9%) patients (3 men and 2 women) aged 31-60 years met the definition. None of the patients was HIV-positive. Although the best available multidrug regimens were initiated, no patient could achieve sputum conversion. Adjuvant resectional surgery was considered because the patients had localized disease. Procedures performed included pneumonectomy (2) and upper lobectomy (3). There was no operative mortality or morbidity. All patients attained sputum-negative status after the operation, and they were maintained on multidrug regimens for 12-25 months postoperatively. All patients remained free from disease at the time of follow-up. Pulmonary resection under cover of state-of-the-art chemotherapy is safe and effective for patients with localized extensively drug-resistant tuberculosis.

  11. Systematic review of the performance of rapid rifampicin resistance testing for drug-resistant tuberculosis.

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    Matthew Arentz

    Full Text Available INTRODUCTION: Rapid tests for rifampicin resistance may be useful for identifying isolates at high risk of drug resistance, including multidrug-resistant TB (MDR-TB. However, choice of diagnostic test and prevalence of rifampicin resistance may both impact a diagnostic strategy for identifying drug resistant-TB. We performed a systematic review to evaluate the performance of WHO-endorsed rapid tests for rifampicin resistance detection. METHODS: We searched MEDLINE, Embase and the Cochrane Library through January 1, 2012. For each rapid test, we determined pooled sensitivity and specificity estimates using a hierarchical random effects model. Predictive values of the tests were determined at different prevalence rates of rifampicin resistance and MDR-TB. RESULTS: We identified 60 publications involving six different tests (INNO-LiPA Rif. TB assay, Genotype MTBDR assay, Genotype MTBDRplus assay, Colorimetric Redox Indicator (CRI assay, Nitrate Reductase Assay (NRA and MODS tests: for all tests, negative predictive values were high when rifampicin resistance prevalence was ≤ 30%. However, positive predictive values were considerably reduced for the INNO-LiPA Rif. TB assay, the MTBDRplus assay and MODS when rifampicin resistance prevalence was < 5%. LIMITATIONS: In many studies, it was unclear whether patient selection or index test performance could have introduced bias. In addition, we were unable to evaluate critical concentration thresholds for the colorimetric tests. DISCUSSION: Rapid tests for rifampicin resistance alone cannot accurately predict rifampicin resistance or MDR-TB in areas with a low prevalence of rifampicin resistance. However, in areas with a high prevalence of rifampicin resistance and MDR-TB, these tests may be a valuable component of an MDR-TB management strategy.

  12. Genome-wide screening of loci associated with drug resistance to 5-fluorouracil-based drugs.

    Science.gov (United States)

    Ooyama, Akio; Okayama, Yoshihiro; Takechi, Teiji; Sugimoto, Yoshikazu; Oka, Toshinori; Fukushima, Masakazu

    2007-04-01

    Resistance to chemotherapeutic agents represents the chief cause of mortality in cancer patients with advanced disease. Chromosomal aberration and altered gene expression are the main genetic mechanisms of tumor chemoresistance. In this study, we have established an algorithm to calculate DNA copy number using the Affymetrix 10K array, and performed a genome-wide correlation analysis between DNA copy number and antitumor activity against 5-fluorouracil (5-FU)-based drugs (S-1, tegafur + uracil [UFT], 5'-DFUR and capecitabine) to screen for loci influencing drug resistance using 27 human cancer xenografts. A correlation analysis confirmed that the single nucleotide polymorphism (SNP) showing significant associations with drug sensitivity were concentrated in some cytogenetic regions (18p, 17p13.2, 17p12, 11q14.1, 11q11 and 11p11.12), and we identified some genes that have been indicated their relations to drug sensitivity. Among these regions, 18p11.32 at the location of the thymidylate synthase gene (TYMS) was strongly associated with resistance to 5-FU-based drugs. A change in copy number of the TYMS gene was reflected in the TYMS expression level, and showed a significant negative correlation with sensitivity against 5-FU-based drugs. These results suggest that amplification of the TYMS gene is associated with innate resistance, supporting the possibility that TYMS copy number might be a predictive marker of drug sensitivity to fluoropyrimidines. Further study is necessary to clarify the functional roles of other genes coded in significant cytogenetic regions. These promising data suggest that a comprehensive DNA copy number analysis might aid in the quest for optimal markers of drug response. PMID:17425594

  13. Prediction of Antifungal Activity of Gemini Imidazolium Compounds

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    Łukasz Pałkowski

    2015-01-01

    Full Text Available The progress of antimicrobial therapy contributes to the development of strains of fungi resistant to antimicrobial drugs. Since cationic surfactants have been described as good antifungals, we present a SAR study of a novel homologous series of 140 bis-quaternary imidazolium chlorides and analyze them with respect to their biological activity against Candida albicans as one of the major opportunistic pathogens causing a wide spectrum of diseases in human beings. We characterize a set of features of these compounds, concerning their structure, molecular descriptors, and surface active properties. SAR study was conducted with the help of the Dominance-Based Rough Set Approach (DRSA, which involves identification of relevant features and relevant combinations of features being in strong relationship with a high antifungal activity of the compounds. The SAR study shows, moreover, that the antifungal activity is dependent on the type of substituents and their position at the chloride moiety, as well as on the surface active properties of the compounds. We also show that molecular descriptors MlogP, HOMO-LUMO gap, total structure connectivity index, and Wiener index may be useful in prediction of antifungal activity of new chemical compounds.

  14. Antiviral drug resistance in Cuban children infected with HIV-1

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    L Pérez

    2012-11-01

    Full Text Available Between 1986 and 2011, 100 children have been diagnosed with HIV-1 in Cuba. 38 have acquired HIV-1 by vertical transmission, 6 by blood transfusion and 56 by sexual contacts (teenager. Currently, AZT/D4T + 3TC + NVP/KALETRA are available for the treatment of pediatric patients. The aim of the study was to monitor the subtype distribution and emergence of drug resistance in pediatric HIV-1 infections. Plasma from 46 HIV-1-infected children were collected from November 2005 to November 2011, subsequently extracted, amplified and sequenced. Phylogenetic analysis was performed using Mega 4 (Neighbour joining, Kimura 2. The CPR tool v6.0 (WHO list 2009 was used to interpret transmitted drug resistance (TDR. In addition, acquired drug resistance was interpreted according to HIVdb v6.1.1. Experiments were successful for 28 samples from 20 patients (5 patients with multiple samples. At the moment of analysis, 17 children were receiving ART. The median age at diagnosis was 1.9 years, whereas the median age at sampling was 4.5 years. Ten children were male (50%, 16 (80% were infected by vertical transmission, 1 by blood transfusion (5% and 3 by sexual route (15%. The subtypes were CRF18_cpx (25%, CRF19_cpx (25%, B (20%, CRF20_BG (10%, G (10%, CRF24_BG (5% and C (5%. 82.3% of the children who were receiving ART at sampling (14/17 displayed at least one drug resistance mutation. The most common NRTI and NNRT mutations were: M184V (55.5%, T215FY (16.6% and K70R (16.6%; and K103NS (61.1% and G190A (22.0%. In contrast, only one PI mutation, L90M (5.5%, was observed. 5.8% of these children displayed single NRTI class resistance, 17.4% single NNRTI class resistance, 59% double NRTI + NNRTI class resistance and 5.8% triple NRTI + NNRTI + PI class resistance. According to HIVdb, NRTI, NNRTI and PI resistance was present in respectively 42.8%, 58.7% and 8.08% of the treated children. High-level NVP and EFV resistance was observed in 76.5% and 58

  15. Sensitive, resistant and multi-drug resistant Acinetobacter baumanii at Saudi Arabia hospital eastern region.

    Science.gov (United States)

    Ahmed, Mughis Uddin; Farooq, Reshma; Al-Hawashim, Nadia; Ahmed, Motasim; Yiannakou, Nearchos; Sayeed, Fatima; Sayed, Ali Rifat; Lutfullah, Sualiha

    2015-05-01

    Since the Physicians start use of antibiotics long ago with un-notice drug resistance. However actual problem was recognized about 85 years ago. Antibiotic resistant and Multi-drug resistant bacterial strains are at rise throughout the world. It is physicians and researchers to take scientific research based appropriate action to overcome this ever-spreading problem. This study is designed to find out sensitive (S), resistant (R) and multi-drug resistant (MDR) Acinetobacter baumanii strain along with other isolates in the resident patients of Eastern Region of Saudi Arabia. Pseudomonas aeruginosa is excluded from other gram-negative organisms isolated from different sites as it will be dealt separately. This study is based in was retrospective observations designed to collect data of different stains of Acinetobacter baumanii with reference to their Sensitivity (S), Resistance (R), Multi-Drug Resistance (MDR) along with other Gram negative isolated from different sites (from 1st January 2004 to 31st December 2011) at King Abdulaziz Hospital located Eastern Region of Kingdom of Saudi Arabia (KSA). All necessary techniques were used to culture and perform sensitivity of these isolates. There were 4532 isolates out of which 3018 (67%) were from patients. Out of Acinetobacter baumanii infected were 906 (20%) while other 3626 (80%) isolates were miscellaneous. Numbers of patients or cases were 480 (53%) out of 906 isolates and numbers of patients or cases in other organisms were 2538 (70%) out of 3626 isolates. Acinetobacter baumanii infected patients 221 (46%) were male and 259 (54%) were female and the male and female ratio of 1:1.2. In other organisms this male female ratio was almost same. There was steady rise in number of patients and the hence the isolates from 2004 to 2011. Majority of the bacterial strains were isolated as single organism but some were isolated as double or triple or quadruple or more organisms from different sites. Sensitive, Resistant and

  16. Drug resistance profiles of Mycobacterium tuberculosis isolates to first line anti-tuberculous drugs: A five years study

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    Sarala Menon

    2012-01-01

    Full Text Available Background: Drug resistance is a major problem in the treatment of tuberculosis (TB. An estimate of drug resistance is extremely important in the epidemiology and control of TB. However, an assessment of the magnitude of drug resistance in TB is not very well described globally and data remains scantier for India. In view of this, we reviewed our data over last five years. Materials and Methods: Six hundred and seventy-three Mycobacterium tuberculosis isolates were subjected to drug susceptibility against primary anti-tuberculosis drugs by economic variant proportion method. All isolates resistant to isoniazid and rifampicin were taken as multi-drug resistant (MDR. Results: Out of the 673 strains tested, 95 (14.11% showed monoresistance, 365 (54.23% strains were found to be resistant to more than one drug. A total of 118 (17.53% strains were found to be resistant to all the four drugs tested. MDR was seen with 320 (47.54% isolates. This study observed maximum resistance with rifampicin (74.4% followed by streptomycin (70.0%, isoniazid (53.2%, and ethambutol (21.7%. Conclusion: While this information may not reflect true prevalence of drug resistance in the region, this may help in further planning long term surveillance studies to know the trend of drug resistance in this area.

  17. Elaboration of a global strategy for containing microbial drug resistance.

    Science.gov (United States)

    Zabicki, W

    2001-01-01

    The World Health Organization is engaged in developing the Global Strategy for Containment of Antimicrobial Resistance. The preliminary document WHO/CDC/CSR/DRS/2000.I Draft has already been distributed, and remarks have been solicited. The World Health Assembly Resolution of 1998 urged Member States to encourage the appropriate and cost-effective use of antimicrobials. Member States were requested to implement effective systems of microbial resistance surveillance and to monitor volumes and patterns of antimicrobial drug use. The phenomenon of antimicrobial resistance is rising rapidly and causing growing international concern. Many countries have undertaken their own national plans to address the problem. The overall aim of the strategy being developed is to find the most effective forms and to prevent the spread of antimicrobial resistance and resistant microbes. The strategy covers the following topics: patients and general community, prescribers, hospitals, veterinarians, manufacturers and drug dispensers, and international aspects. The strategy is being developed on the basis of expert opinions, published reports, reviews of specific topics specially commissioned by various international and national bodies, and a large body of literature with a list of publications containing over 100 items. PMID:17986973

  18. [MOLECULAR MECHANISMS OF DRUG RESISTANCE NEISSERIA GONORRHOEAE HISTORY AND PROSPECTS].

    Science.gov (United States)

    Bodoev, I N; Il'ina, E N

    2015-01-01

    Neisseria gonorrhoeae (gonococcus) is a strict human pathogen, which causes gonorrhea--an infectious disease, whose origin dates back to more than two thousand years. Due to the unique plasticity of the genetic material, these bacteria have acquired the capacity to adapt to the host immune system, cause repeated infections, as well as withstand antimicrobials. Since the introduction of antibiotics in 1930s, gonococcus has displayed its propensity to develop resistance to all clinically useful antibiotics. It is important to note that the known resistance determinants of N. gonorrhoeae were acquired through horizontal gene transfer, recombination and spontaneous mutagenesis, and may be located both in the chromosome and on the plasmid. After introduction of a new antimicrobial drug, gonococcus becomes resistant within two decades and replaces sensitive bacterial population. Currently Ceftriaxone is the last remaining antibiotic for first-line treatment of gonorrhea. However, the first gonococcus displaying high-level resistance to Ceftriaxone was isolated in Japan a few years ago. Therefore, in the near future, gonorrhea may become untreatable. In the present review, we discuss the chronology of the anti-gonorrhea drugs (antibiotics) replacement, the evolution of resistance mechanisms emergence and future perspectives of N. gonorrhoeae treatment.

  19. Fighting drug-resistant Plasmodium falciparum: the challenge of artemisinin resistance.

    Science.gov (United States)

    Wongsrichanalai, C; Sibley, C H

    2013-10-01

    Following a decade-long scale up of malaria control through vector control interventions, the introduction of rapid diagnostic tests and highly efficacious Artemisinin-based Combination Therapy (ACT) along with other measures, global malaria incidence declined significantly. The recent development of artemisinin resistance on the Cambodia-Thailand border, however, is of great concern. This review encompasses the background of artemisinin resistance in Plasmodium falciparum, its situation, especially in the Greater Mekong Sub-region (GMS), and the responses taken to overcome this resistance. The difficulties in defining resistance are presented, particularly the necessity of measuring the clinical response to artemisinins using the slow parasite-clearance phenotype. Efforts to understand the molecular basis of artemisinin resistance and the search for molecular markers are reviewed. The markers, once identified, can be applied as an efficient tool for resistance surveillance. Despite the limitation of current surveillance methods, it is important to continue vigilance for artemisinin resistance. The therapeutic efficacy "in vivo study" network for monitoring antimalarial resistance in the GMS has been strengthened. GMS countries are working together in response to artemisinin resistance and aim to eliminate all P. falciparum parasites. These efforts are crucial since a resurgence of malaria due to drug and/or insecticide resistance, program cuts, lack of political support and donor fatigue could set back malaria control success in the sub-region and threaten malaria control and elimination if resistance spreads to other regions.

  20. The management of drug resistant seizures in tuberous sclerosis

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    Romina MOAVERO

    2009-12-01

    Full Text Available Tuberous Sclerosis Complex (TSC is a multisystem autosomal dominant genetic disorder resulting from mutations in one of two genes, TSC1 and TSC2. Pathologically TSC is characterized by abnormal cellular differentiation and proliferation, as well as abnormal neuronal migration. The majority of patients with TSC have epilepsy, although the mechanisms underlying epileptogenesis remain unknown. Seizures onset is frequently during the first year of life, and in a sizable proportion of individuals tend to be refractory to antiepileptic drug treatment. This article reviews the progress in understanding drug resistant seizures in TSC, from molecular pathogenesis to the pathophysiological mechanisms of epileptogenesis, and the rationale for appropriate medical and surgical treatment.

  1. Drug accumulation in the presence of the multidrug resistance pump

    DEFF Research Database (Denmark)

    Ayesh, S; Litman, Thomas; Stein, W D

    1997-01-01

    We studied the interaction between the multidrug transporter, P-glycoprotein, and two compounds that interact with it: vinblastine, a classical substrate of the pump, and verapamil, a classical reverser. Steady-state levels of accumulation of these two drugs were determined in a multidrug resistant...... P388 leukemia cell line, P388/ADR. The time course of accumulation of these drugs, and the effect of energy starvation and the presence of chloroquine on the level of their steady-state accumulation were quite disparate. Vinblastine inhibited the accumulation of verapamil whereas it enhanced...

  2. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine.

    Science.gov (United States)

    Almeida-Paes, Rodrigo; Figueiredo-Carvalho, Maria Helena Galdino; Brito-Santos, Fábio; Almeida-Silva, Fernando; Oliveira, Manoel Marques Evangelista; Zancopé-Oliveira, Rosely Maria

    2016-01-01

    Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.

  3. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine.

    Directory of Open Access Journals (Sweden)

    Rodrigo Almeida-Paes

    Full Text Available Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC and minimal fungicidal concentrations (MFC of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies.

  4. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine.

    Science.gov (United States)

    Almeida-Paes, Rodrigo; Figueiredo-Carvalho, Maria Helena Galdino; Brito-Santos, Fábio; Almeida-Silva, Fernando; Oliveira, Manoel Marques Evangelista; Zancopé-Oliveira, Rosely Maria

    2016-01-01

    Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies. PMID:27031728

  5. Melanins Protect Sporothrix brasiliensis and Sporothrix schenckii from the Antifungal Effects of Terbinafine

    Science.gov (United States)

    Almeida-Paes, Rodrigo; Figueiredo-Carvalho, Maria Helena Galdino; Brito-Santos, Fábio; Almeida-Silva, Fernando; Oliveira, Manoel Marques Evangelista; Zancopé-Oliveira, Rosely Maria

    2016-01-01

    Terbinafine is a recommended therapeutic alternative for patients with sporotrichosis who cannot use itraconazole due to drug interactions or side effects. Melanins are involved in resistance to antifungal drugs and Sporothrix species produce three different types of melanin. Therefore, in this study we evaluated whether Sporothrix melanins impact the efficacy of antifungal drugs. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of two Sporothrix brasiliensis and four Sporothrix schenckii strains grown in the presence of the melanin precursors L-DOPA and L-tyrosine were similar to the MIC determined by the CLSI standard protocol for S. schenckii susceptibility to amphotericin B, ketoconazole, itraconazole or terbinafine. When MICs were determined in the presence of inhibitors to three pathways of melanin synthesis, we observed, in four strains, an increase in terbinafine susceptibility in the presence of tricyclazole, a DHN-melanin inhibitor. In addition, one S. schenckii strain grown in the presence of L-DOPA had a higher MFC value when compared to the control. Growth curves in presence of 2×MIC concentrations of terbinafine showed that pyomelanin and, to a lesser extent, eumelanin were able to protect the fungi against the fungicidal effect of this antifungal drug. Our results suggest that melanin protects the major pathogenic species of the Sporothrix complex from the effects of terbinafine and that the development of new antifungal drugs targeting melanin synthesis may improve sporotrichosis therapies. PMID:27031728

  6. Multi drug resistant tuberculosis presenting as anterior mediastinal mass

    Directory of Open Access Journals (Sweden)

    Parmarth Chandane

    2016-01-01

    Full Text Available Enlargement of the mediastinal lymphatic glands is a common presentation of intrathoracic tuberculosis (TB in children. However, usually, the mediastinal TB nodes enlarge to 2.8 ± 1.0 cm. In this report, we describe a case of anterior mediastinal lymphnode TB seen as huge mass (7 cm on computed tomography (CT thorax without respiratory or food pipe compromise despite anterior mediastinum being an enclosed space. CT guided biopsy of the mass cultured Mycobacterium TB complex which was resistant to isoniazide, rifampicin, streptomycin ofloxacin, moxifloxacin, and pyrazinamide. Hence, we report primary multi drug resistant TB presenting as anterior mediastinal mass as a rare case report.

  7. 2009-2013年某医院抗真菌药使用情况分析%Analysis of the Use of Antifungal Drugs in a Hospital from 2009 to 2013

    Institute of Scientific and Technical Information of China (English)

    范玉田; 王春艳

    2015-01-01

    Objective: To summarize and analyze the utilization of antifungal drugs in our hospital, so as to provide references for the rational drug use and the effective management of clinical medication.Methods:Pharmaco-economic theory was used to conduct caculations and the statistic analysis of the deifned daily dose (DDD), the amount and costs of antifungal medication, frequency of administration (DDDs), the daily cost (DUC) so on of antifungal and so on in our hospital during the years of 2009-2013.Results:The varieties, use amount and sales amount of antifungal drugs showed an increasing trend. The use intensity of nystatin tablets and imported lfuconazole injection rose steadily by year too.Conclusion:The use of antifungal drugs was basically stable in our hospital. However, there is still the need to strengthen the clinical management of antifungal drugs, reduce possible factors for fungal infections and promote rational use of drugs.%目的:对我院抗真菌药物的使用情况进行统计与分析,为临床合理用药和有效管理提供参考。方法:运用药物经济学原理,使用限定日剂量(DDD),对2009-2013年我院抗真菌药物用药数量与金额、用药频率(DDDs)、日均费用(DUC)等进行统计与分析。结果:我院抗真菌药物品种、使用数量和销售金额均呈逐年上升趋势。制霉菌素片及进口氟康唑注射液使用强度呈逐年增加趋势。结论:我院抗真菌药物的使用情况基本稳定。但仍应进一步加强抗真菌药物的临床管理,减少真菌感染的可能因素,促进药物合理应用。

  8. 2010~2012年我院深部抗真菌药使用情况分析%Analysis of deep antifungal drugs in Shidong hospital from 2010 to 2012

    Institute of Scientific and Technical Information of China (English)

    毛亚佩; 李婷; 卫英

    2014-01-01

    Objective To evaluate the utilization of deep antifungal drugs in our hospital,so as to provide evidence for the effective management of medication. Methods The defined daily dose (DDD) was used as the unit.The usage figure and consumption sum of deep antifungal drugs,DDC,DUI and AUD were analyzed in our hospital from 2010 to 2012. Results The kinds, usage figure and consumption sum of deep antifungal drugs were increasing over the 3 years.The consumption sum of Fluconazole was accounted for more than 70% of all deep antifungal drugs in three years.And the antibiotics use densities (AUD) of deep antifungal drugs presented clearly growing trend. Conclusion In order to promote the rational use of deep antifungal drugs,the causes should be further analyzed.%目的:对我院深部抗真菌药物的使用情况进行统计与评价,为临床合理用药和有效管理提供参考。方法使用限定日剂量(DDD)作为分析单位,计算累积DDDs,并以此为基础对2010~2012年我院(二级甲等)住院患者的深部抗真菌药物用药数量与金额、日均费用(DDC)、药物利用指数(DUI)、药物使用强度(AUD)进行统计计算。结果我院深部抗真菌药品种、使用数量和销售金额均呈逐年上升趋势。氟康唑是治疗深部真菌感染的主要药品。深部抗真菌药的用药强度逐年增长趋势明显。结论为促进抗菌药物合理应用,需进一步分析原因,加强监控。

  9. Metabolism and resistance of Fusarium spp. to the manzamine alkaloids via a putative retro pictet-spengler reaction and utility of the rational design of antimalarial and antifungal agents.

    Science.gov (United States)

    Kasanah, Noer; Farr, Lorelei Lucas; Gholipour, Abbas; Wedge, David E; Hamann, Mark T

    2014-08-01

    As a part of our continuing investigation of the manzamine alkaloids we studied the in vitro activity of the β-carboline containing manzamine alkaloids against Fusarium solani, Fusarium oxysporium, and Fusarium proliferatum by employing several bioassay techniques including one-dimensional direct bioautography, dilution, and plate susceptibility, and microtiter broth assays. In addition, we also studied the metabolism of the manzamine alkaloids by Fusarium spp. in order to facilitate the redesign of the compounds to prevent resistance of Fusarium spp. through metabolism. The present research reveals that the manzamine alkaloids are inactive against Fusarium spp. and the fungi transform manzamines via hydrolysis, reduction, and a retro Pictet-Spengler reaction. This is the first report to demonstrate an enzymatically retro Pictet-Spengler reaction. The results of this study reveal the utility of the rational design of metabolically stable antifungal agents from this class and the development of manzamine alkaloids as antimalarial drugs through the utilization of Fusarium's metabolic products to reconstruct the molecule.

  10. Lenghty reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) polymeric micelles and gels for sustained release of antifungal drugs.

    Science.gov (United States)

    Figueroa-Ochoa, Edgar B; Villar-Alvarez, Eva M; Cambón, Adriana; Mistry, Dharmista; Llovo, José; Attwood, David; Barbosa, Silvia; Soltero, J F Armando; Taboada, Pablo

    2016-08-20

    In this work, we present a detailed study of the potential application of polymeric micelles and gels of four different reverse triblock poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) copolymers (BOnEOmBOn, where n denotes the respective block lengths), specifically BO8EO90BO8, BO14EO378BO14, BO20EO411BO20 and BO21EO385BO21, as effective drug transport nanocarriers. In particular, we tested the use of this kind of polymeric nanostructures as reservoirs for the sustained delivery of the antifungals griseofulvin and fluconazole for oral and topical administration. Polymeric micelles and gels formed by these copolymers were shown to solubilize important amounts of these two drugs and to have a good stability in physiologically relevant conditions for oral or topical administration. These polymeric micellar nanocarriers were able to release drugs in a sustained manner, being the release rate slower as the copolymer chain hydrophobicity increased. Different sustained drug release profiles were observed depending on the medium conditions. Gel nanocarriers were shown to display longer sustained release rates than micellar formulations, with the existence of a pulsatile-like release mode under certain solution conditions as a result of their inner network structure. Certain bioadhesive properties were observed for the polymeric physical gels, being moderately tuned by the length and hydrophobicity of the polymeric chains. Furthermore, polymeric gels and micelles showed activity against the yeast Candida albicans and the mould demartophytes (Trichophyton rubrum and Microsporum canis) and, thus, may be useful for the treatment of different cutaneous fungal infections. PMID:27289012

  11. Analysis of Etiology and Drug Resistance of Biliary Infections

    Institute of Scientific and Technical Information of China (English)

    王欣; 李秋; 邹声泉; 孙自庸; 朱峰

    2004-01-01

    The bile was collected from fro patients with biliary infections, with the bacterium isolated to study the sensitivity of each kind of the bacterium to several antibiotics in common use. Except G- bacterium, we also found some kinds of G+ bacterium in infection bile. G- bacterium were not sensitive to Clindamycin, G+ bacterium were sensitive to Ciprofloxacin. Escherichia coli,Xanthomonas maltophilia, Enterobacter cloacae, Pseudomonas aeruginosa were sensitive to Ampicillin. G+ bacterium were not sensitive to Azactam. Enterococcus faecalis, Enterococcus faecium,Enterobacter cloacae were not sensitive to Ceftazidime. Enterococcus faecalis, Staphylococcus coagulase negative, Staphylococcus epidermidis, Pseudomonas aeruginosa were not sensitive to Ceftriaxone Sodium. We didn't found any bacterium resistance Imipenem. The possibility of the existence of G+ bacterium as well as drug resistance should be considered n patients with biliary infections.The value of susceptibility test should be respected to avoid drug abuse of antibiotics.

  12. Mathematical models of tumor heterogeneity and drug resistance

    Science.gov (United States)

    Greene, James

    In this dissertation we develop mathematical models of tumor heterogeneity and drug resistance in cancer chemotherapy. Resistance to chemotherapy is one of the major causes of the failure of cancer treatment. Furthermore, recent experimental evidence suggests that drug resistance is a complex biological phenomena, with many influences that interact nonlinearly. Here we study the influence of such heterogeneity on treatment outcomes, both in general frameworks and under specific mechanisms. We begin by developing a mathematical framework for describing multi-drug resistance to cancer. Heterogeneity is reflected by a continuous parameter, which can either describe a single resistance mechanism (such as the expression of P-gp in the cellular membrane) or can account for the cumulative effect of several mechanisms and factors. The model is written as a system of integro-differential equations, structured by the continuous "trait," and includes density effects as well as mutations. We study the limiting behavior of the model, both analytically and numerically, and apply it to study treatment protocols. We next study a specific mechanism of tumor heterogeneity and its influence on cell growth: the cell-cycle. We derive two novel mathematical models, a stochastic agent-based model and an integro-differential equation model, each of which describes the growth of cancer cells as a dynamic transition between proliferative and quiescent states. By examining the role all parameters play in the evolution of intrinsic tumor heterogeneity, and the sensitivity of the population growth to parameter values, we show that the cell-cycle length has the most significant effect on the growth dynamics. In addition, we demonstrate that the agent-based model can be approximated well by the more computationally efficient integro-differential equations, when the number of cells is large. The model is closely tied to experimental data of cell growth, and includes a novel implementation of

  13. Multi-drug resistant Acinetobacter ventilator-associated pneumonia

    OpenAIRE

    Shete, Vishal B.; Dnyaneshwari P Ghadage; Vrishali A Muley; Bhore, Arvind V.

    2010-01-01

    Background: Ventilator-associated pneumonia (VAP) due to a multi-drug resistant (MDR) Acinetobacter is one of the most dreadful complications, which occurs in the critical care setting. Aims and objectives: To find out the incidence of Acinetobacter infection in VAP cases, to determine various risk factors responsible for acquisition of Acinetobacter infection and to determine the antimicrobial susceptibility pattern of Acinetobacter. Materials and Methods: A total of 60 endotracheal aspirate...

  14. Risk factors for anti-MRSA drug resistance.

    Science.gov (United States)

    Abe, Yasuhisa; Shigemura, Katsumi; Yoshida, Hiroyuki; Fujisawa, Masato; Arakawa, Soichi

    2012-11-01

    Meticillin-resistant Staphylococcus aureus (MRSA)-related infections have recently been spreading and are difficult to control, partly because affected patients are frequently in a poor condition. This study retrospectively investigated recent MRSA-related infections focusing on the relationship between clinical risk factors and anti-MRSA drug resistance. The patients with MRSA-related infections in Kobe University Hospital (Kobe, Japan) in 2009 were enrolled in the study. The relationships between various clinical risk factors as well as MRSA bacterial DNA concentration with minimum inhibitory concentrations (MICs) of anti-MRSA drugs were examined. In total, 44 patients were enrolled in the study and MRSA was isolated from blood (23 patients), urine (12 patients) and nasal secretions (9 patients). There was only one resistant strain to linezolid (LZD) among the anti-MRSA drugs tested, and this strain was considered staphylococcal cassette chromosome mec (SCCmec) type IIa from phage open-reading frame typing analyses. Statistical analyses showed that MRSA bacterial DNA concentration, cancer and use of a respirator, respectively, had a significant relationship with the MICs of LZD (P=0.0058) and arbekacin (ABK) (P=0.0003), of quinupristin/dalfopristin (Q/D) (P=0.0500) and ABK (P=0.0133), and of Q/D (P=0.0198) and vancomycin (P=0.0036). In conclusion, bacterial DNA concentration, cancer and use of a respirator were found to be significant risk factors for lower susceptibilities to anti-MRSA drugs; one strain was resistant to LZD. We suggest that further investigation and surveillance for MRSA-related infection are necessary for preventing the spread of MRSA-related infections. PMID:22999766

  15. Anti-tuberculosis drug resistance in Sub-Saharan Africa: The case of Uganda

    OpenAIRE

    Cobelens, F.G.J.; Joloba, M.L.; Lukoye, D

    2015-01-01

    This thesis reports findings of six studies including two tuberculosis (TB) drug resistance surveys, a comparative study of HIV infection rates among patients enrolled in the survey and those under routine TB/HIV surveillance, two TB molecular epidemiological analyses and a systematic review and meta-analysis of drug-resistant TB in sub-Saharan Africa. It provides a general introduction to anti-tuberculosis drug resistance in the world and associated risk factors. Results from the drug resist...

  16. New drugs to treat multidrug-resistant tuberculosis: the case for bedaquiline

    OpenAIRE

    Leibert E; Danckers M; Rom WN

    2014-01-01

    Eric Leibert, Mauricio Danckers, William N Rom Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, New York University School of Medicine, New York, NY, USA Abstract: Mycobacterium tuberculosis develops spontaneous resistance mutants to virtually every drug in use. Courses of therapy select for these mutants and drug-resistant organisms emerge. The development of drug-resistant organisms has reached the point that drug resistance now threatens to undermi...

  17. Assessing transmissibility of HIV-1 drug resistance mutations from treated and from drug-naive individuals

    Science.gov (United States)

    Winand, Raf; Theys, Kristof; Eusébio, Mónica; Aerts, Jan; Camacho, Ricardo J.; Gomes, Perpetua; Suchard, Marc A.; Vandamme, Anne-Mieke; Abecasis, Ana B.

    2015-01-01

    Objectives: Surveillance drug resistance mutations (SDRMs) in drug-naive patients are typically used to survey HIV-1-transmitted drug resistance (TDR). We test here how SDRMs in patients failing treatment, the original source of TDR, contribute to assessing TDR, transmissibility and transmission source of SDRMs. Design: This is a retrospective observational study analyzing a Portuguese cohort of HIV-1-infected patients. Methods: The prevalence of SDRMs to protease inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs) in drug-naive and treatment-failing patients was measured for 3554 HIV-1 subtype B patients. Transmission ratio (prevalence in drug-naive/prevalence in treatment-failing patients), average viral load and robust linear regression with outlier detection (prevalence in drug-naive versus in treatment-failing patients) were analyzed and used to interpret transmissibility. Results: Prevalence of SDRMs in drug-naive and treatment-failing patients were linearly correlated, but some SDRMs were classified as outliers – above (PRO: D30N, N88D/S, L90 M, RT: G190A/S/E) or below (RT: M184I/V) expectations. The normalized regression slope was 0.073 for protease inhibitors, 0.084 for NRTIs and 0.116 for NNRTIs. Differences between SDRMs transmission ratios were not associated with differences in viral loads. Conclusion: The significant linear correlation between prevalence of SDRMs in drug-naive and in treatment-failing patients indicates that the prevalence in treatment-failing patients can be useful to predict levels of TDR. The slope is a cohort-dependent estimate of rate of TDR per drug class and outlier detection reveals comparative persistence of SDRMs. Outlier SDRMs with higher transmissibility are more persistent and more likely to have been acquired from drug-naive patients. Those with lower transmissibility have faster reversion dynamics after transmission and are associated with

  18. Molecular Genetics of Drug-resistance in Epilepsies

    Directory of Open Access Journals (Sweden)

    Kurupath Radhakrishnan

    2015-06-01

    Full Text Available Nearly one-third of newly diagnosed patients with epilepsy remain unresponsive to antiepileptic drugs (AEDs, etiopathogenesis of which is poorly understood. The genes encoding the proteins that regulate the pharmacokinetics such as P-glycoprotein [ABCBI], major vault protein [MVP gene] and drug metabolizing enzymes [ABCB1, ABCG2, MVP, CYP2C9, CYP2C19, CYP3A4, CYP3A5, EPHX1, UGT1A1, UGT2B7], and pharmacodynamics such as sodium channels [SCN1A, SCN2A] and GABA receptors [GABRA1, GABRA6, GABRB2, GABRG2] of AEDs are under intense investigation to unravel the mysteries of AED-resistance. However, till today, a consistent and reliable result that could help the clinician either to predict drug resistance or to overcome it has not been forthcoming. The discrepant results may be related to variations in the definition of drug-resistance, heterogeneous patient populations, ethnic variations in the frequency distribution of single nucleotide polymorphisms (SNPs and the selection of SNPs. Understanding of these limitations of existing studies, hopefully, will help in designing better studies. Nearly one-third of newly diagnosed patients with epilepsy remain unresponsive toantiepileptic drugs (AEDs, etiopathogenesis of which is poorly understood. The genesencoding the proteins that regulate the pharmacokinetics such as P-glycoprotein[ABCBI], major vault protein [MVP gene] and drug metabolizing enzymes [ABCB1,ABCG2, MVP, CYP2C9, CYP2C19, CYP3A4, CYP3A5, EPHX1, UGT1A1, UGT2B7],and pharmacodynamics such as sodium channels [SCN1A, SCN2A] and GABAreceptors [GABRA1, GABRA6, GABRB2, GABRG2] of AEDs are under intenseinvestigation to unravel the mysteries of AED-resistance. However, till today, aconsistent and reliable result that could help the clinician either to predict drugresistanceor to overcome it has not been forthcoming. The discrepant results may berelated to variations in the definition of drug-resistance, heterogeneous patientpopulations, ethnic

  19. Additional Drug Resistance of Multidrug-Resistant Tuberculosis in Patients in 9 Countries

    OpenAIRE

    Kurbatova, Ekaterina V.; Dalton, Tracy; Ershova, Julia; Tupasi, Thelma; Caoili, Janice Campos; van der Walt, Martie; Kvasnovsky, Charlotte; Yagui, Martin; Bayona, Jaime; Contreras, Carmen; Leimane, Vaira; Via, Laura E.; Kim, HeeJin; Akksilp, Somsak; Kazennyy, Boris Y.

    2015-01-01

    Data from a large multicenter observational study of patients with multidrug-resistant tuberculosis (MDR TB) were analyzed to simulate the possible use of 2 new approaches to treatment of MDR TB: a short (9-month) regimen and a bedaquiline-containing regimen. Of 1,254 patients, 952 (75.9%) had no resistance to fluoroquinolones and second-line injectable drugs and thus would qualify as candidates for the 9-month regimen; 302 (24.1%) patients with resistance to a fluoroquinolone or second-line ...

  20. Definition of drug resistance of Mycobacterium tuberculosis to antituberculosis drugs in patients with multidrugresistant tuberculosis and TB with extremely drug resistant depending on the case of the disease

    Directory of Open Access Journals (Sweden)

    Kryzhanovsky D.G.

    2014-11-01

    Full Text Available There was studied the profile of drug resistance to the main (I line and reserve (II line antituberculosis drugs in patients with MDR and XDR tuberculosis, depending of the case of the disease. According to the randomized retrospective research 200 patients with MDR and XDR tuberculosis, who received treatment in the clinic of hospital Municipal institution «Dnipropetrovsk rigional clinical association «Phthisiology» Dnipropetrovsk regional Council» during the period 2010 – 2012 were involved. Data about patients contained the data on a case of the disease and the results of the test of drug sensitivity to MBT. XDR – TB was revealed in 7.5% of patients with MDR tuberculosis. In patients with MDR tuberculosis as compared with patients with XDR tuberculosis «new cases» were diagnosed in 19.5% against 18.5% (p <0.05. In patients with MDR tuberculosis and with XDR tuberculosis resistance to the antituberculosis drug more commonly developed to S - 88.5%, E - 55% and Z - 24%. The presence of MDR-TB and XDR-TB prevails in patients, who underwent previous courses of treatment with anti-TB drugs in case history as compared with patients with «new cases» of treatment. The development of resistance to anti-TB drugs depends on the availability of these drugs in the previous treatment regimens.

  1. Surfactant-based drug delivery systems for treating drug-resistant lung cancer.

    Science.gov (United States)

    Kaur, Prabhjot; Garg, Tarun; Rath, Goutam; Murthy, R S R; Goyal, Amit K

    2016-01-01

    Among all cancers, lung cancer is the major cause of deaths. Lung cancer can be categorized into two classes for prognostic and treatment purposes: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Both categories of cancer are resistant to certain drugs. Various mechanisms behind drug resistance are over-expression of superficial membrane proteins [glycoprotein (P-gp)], lung resistance-associated proteins, aberration of the intracellular enzyme system, enhancement of the cell repair system and deregulation of cell apoptosis. Structure-performance relationships and chemical compatibility are consequently major fundamentals in surfactant-based formulations, with the intention that a great deal investigation is committed to this region. With the purpose to understand the potential of P-gp in transportation of anti-tumor drugs to cancer cells with much effectiveness and specificity, several surfactant-based delivery systems have been developed which may include microspheres, nanosized drug carriers (nanoparticles, nanoemulsions, stealth liposomes, nanogels, polymer-drug conjugates), novel powders, hydrogels and mixed micellar systems intended for systemic and/or localized delivery. PMID:25013959

  2. HIV-1 Drug Resistance Mutations: Potential Applications for Point-of-Care Genotypic Resistance Testing.

    Directory of Open Access Journals (Sweden)

    Soo-Yon Rhee

    Full Text Available The increasing prevalence of acquired and transmitted HIV-1 drug resistance is an obstacle to successful antiretroviral therapy (ART in the low- and middle-income countries (LMICs hardest hit by the HIV-1 pandemic. Genotypic drug resistance testing could facilitate the choice of initial ART in areas with rising transmitted drug resistance (TDR and enable care-providers to determine which individuals with virological failure (VF on a first- or second-line ART regimen require a change in treatment. An inexpensive near point-of-care (POC genotypic resistance test would be useful in settings where the resources, capacity, and infrastructure to perform standard genotypic drug resistance testing are limited. Such a test would be particularly useful in conjunction with the POC HIV-1 viral load tests that are currently being introduced in LMICs. A POC genotypic resistance test is likely to involve the use of allele-specific point mutation assays for detecting drug-resistance mutations (DRMs. This study proposes that two major nucleoside reverse transcriptase inhibitor (NRTI-associated DRMs (M184V and K65R and four major NNRTI-associated DRMs (K103N, Y181C, G190A, and V106M would be the most useful for POC genotypic resistance testing in LMIC settings. One or more of these six DRMs was present in 61.2% of analyzed virus sequences from ART-naïve individuals with intermediate or high-level TDR and 98.8% of analyzed virus sequences from individuals on a first-line NRTI/NNRTI-containing regimen with intermediate or high-level acquired drug resistance. The detection of one or more of these DRMs in an ART-naïve individual or in a individual with VF on a first-line NRTI/NNRTI-containing regimen may be considered an indication for a protease inhibitor (PI-containing regimen or closer virological monitoring based on cost-effectiveness or country policy.

  3. HIV-1 Drug Resistance Mutations: Potential Applications for Point-of-Care Genotypic Resistance Testing.

    Science.gov (United States)

    Rhee, Soo-Yon; Jordan, Michael R; Raizes, Elliot; Chua, Arlene; Parkin, Neil; Kantor, Rami; Van Zyl, Gert U; Mukui, Irene; Hosseinipour, Mina C; Frenkel, Lisa M; Ndembi, Nicaise; Hamers, Raph L; Rinke de Wit, Tobias F; Wallis, Carole L; Gupta, Ravindra K; Fokam, Joseph; Zeh, Clement; Schapiro, Jonathan M; Carmona, Sergio; Katzenstein, David; Tang, Michele; Aghokeng, Avelin F; De Oliveira, Tulio; Wensing, Annemarie M J; Gallant, Joel E; Wainberg, Mark A; Richman, Douglas D; Fitzgibbon, Joseph E; Schito, Marco; Bertagnolio, Silvia; Yang, Chunfu; Shafer, Robert W

    2015-01-01

    The increasing prevalence of acquired and transmitted HIV-1 drug resistance is an obstacle to successful antiretroviral therapy (ART) in the low- and middle-income countries (LMICs) hardest hit by the HIV-1 pandemic. Genotypic drug resistance testing could facilitate the choice of initial ART in areas with rising transmitted drug resistance (TDR) and enable care-providers to determine which individuals with virological failure (VF) on a first- or second-line ART regimen require a change in treatment. An inexpensive near point-of-care (POC) genotypic resistance test would be useful in settings where the resources, capacity, and infrastructure to perform standard genotypic drug resistance testing are limited. Such a test would be particularly useful in conjunction with the POC HIV-1 viral load tests that are currently being introduced in LMICs. A POC genotypic resistance test is likely to involve the use of allele-specific point mutation assays for detecting drug-resistance mutations (DRMs). This study proposes that two major nucleoside reverse transcriptase inhibitor (NRTI)-associated DRMs (M184V and K65R) and four major NNRTI-associated DRMs (K103N, Y181C, G190A, and V106M) would be the most useful for POC genotypic resistance testing in LMIC settings. One or more of these six DRMs was present in 61.2% of analyzed virus sequences from ART-naïve individuals with intermediate or high-level TDR and 98.8% of analyzed virus sequences from individuals on a first-line NRTI/NNRTI-containing regimen with intermediate or high-level acquired drug resistance. The detection of one or more of these DRMs in an ART-naïve individual or in a individual with VF on a first-line NRTI/NNRTI-containing regimen may be considered an indication for a protease inhibitor (PI)-containing regimen or closer virological monitoring based on cost-effectiveness or country policy. PMID:26717411

  4. Exosomes in development, metastasis and drug resistance of breast cancer.

    Science.gov (United States)

    Yu, Dan-dan; Wu, Ying; Shen, Hong-yu; Lv, Meng-meng; Chen, Wei-xian; Zhang, Xiao-hui; Zhong, Shan-liang; Tang, Jin-hai; Zhao, Jian-hua

    2015-08-01

    Transport through the cell membrane can be divided into active, passive and vesicular types (exosomes). Exosomes are nano-sized vesicles released by a variety of cells. Emerging evidence shows that exosomes play a critical role in cancers. Exosomes mediate communication between stroma and cancer cells through the transfer of nucleic acid and proteins. It is demonstrated that the contents and the quantity of exosomes will change after occurrence of cancers. Over the last decade, growing attention has been paid to the role of exosomes in the development of breast cancer, the most life-threatening cancer in women. Breast cancer could induce salivary glands to secret specific exosomes, which could be used as biomarkers in the diagnosis of early breast cancer. Exosome-delivered nucleic acid and proteins partly facilitate the tumorigenesis, metastasis and resistance of breast cancer. Exosomes could also transmit anti-cancer drugs outside breast cancer cells, therefore leading to drug resistance. However, exosomes are effective tools for transportation of anti-cancer drugs with lower immunogenicity and toxicity. This is a promising way to establish a drug delivery system.

  5. Epidemiology and antifungal susceptibilities of yeasts causing vulvovaginitis in a teaching hospital.

    Science.gov (United States)

    Gamarra, Soledad; Morano, Susana; Dudiuk, Catiana; Mancilla, Estefanía; Nardin, María Elena; de Los Angeles Méndez, Emilce; Garcia-Effron, Guillermo

    2014-10-01

    Vulvovaginal candidiasis is one of the most common mycosis. However, the information about antifungal susceptibilities of the yeasts causing this infection is scant. We studied 121 yeasts isolated from 118 patients with vulvovaginal candidiasis. The isolates were identified by phenotypic and molecular methods, including four phenotypic methods described to differentiate Candida albicans from C. dubliniensis. Antifungal susceptibility testing was performed according to CLSI documents M27A3 and M27S4 using the drugs available as treatment option in the hospital. Diabetes, any antibacterial and amoxicillin treatment were statistically linked with vulvovaginal candidiasis, while oral contraceptives were not considered a risk factor. Previous azole-based over-the-counter antifungal treatment was statistically associated with non-C.albicans yeasts infections. The most common isolated yeast species was C. albicans (85.2 %) followed by C. glabrata (5 %), Saccharomyces cerevisiae (3.3 %), and C. dubliniensis (2.5 %). Fluconazole- and itraconazole-reduced susceptibility was observed in ten and in only one C. albicans strains, respectively. All the C. glabrata isolates showed low fluconazole MICs. Clotrimazole showed excellent potency against all but seven isolates (three C. glabrata, two S. cerevisiae, one C. albicans and one Picchia anomala). Any of the strains showed nystatin reduced susceptibility. On the other hand, terbinafine was the less potent drug. Antifungal resistance is still a rare phenomenon supporting the use of azole antifungals as empirical treatment of vulvovaginal candidiasis. PMID:25005365

  6. Bypass of Tumor Drug Resistance by Antivascular Therapy

    Directory of Open Access Journals (Sweden)

    Dina Preise

    2003-11-01

    Full Text Available Multidrug resistance (MDR presents a major obstacle for the successful chemotherapy of cancer. Its emergence during chemotherapy is attributed to a selective process, which gives a growth advantage to MDR cells within the genetically unstable neoplastic cell population. The pleiotropic nature of clinical MDR poses a great difficulty for the development of treatment strategies that aim at blocking MDR at the tumor cell level. Targeting treatment to the nonmalignant vascular network—the lifeline of the tumor—is a promising alternative for the treatment of drug-resistant tumors. The present study demonstrates that MDR in cancer can be successfully circumvented by photodynamic therapy (PDT using an antivascular treatment protocol. We show that, although P-glycoprotein-expressing human HT29/MDR colon carcinoma cells in culture are resistant to PDT with Pd-bacteriopheophorbide (TOOKAD, the same treatment induces tumor necrosis with equal efficacy (88% vs 82% in HT29/MDR-derived xenografts and their wild type counterparts, respectively. These results are ascribed to the rapid antivascular effects of the treatment, supporting the hypothesis that MDR tumors can be successfully eradicated by indirect approaches that bypass their inherent drug resistance. We suggest that with progress in ongoing clinical trials, TOOKAD-PDT may offer a novel option for local treatment of MDR tumors.

  7. The new concepts on overcoming drug resistance in lung cancer

    Directory of Open Access Journals (Sweden)

    Zhang W

    2014-06-01

    Full Text Available Weisan Zhang,1 Ping Lei,1 Xifeng Dong,2 Cuiping Xu31Department of Geriatrics, 2Department of Hematology-Oncology, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China; 3Qianfoshan Hospital, Shandong University, Jinan, People’s Republic of ChinaAbstract: Lung cancer is one of the most deadly diseases worldwide. The current first-line therapies include chemotherapy using epidermal growth factor receptor tyrosine kinase inhibitors and radiotherapies. With the current progress in identifying new molecular targets, acquired drug resistance stands as an obstacle for good prognosis. About half the patients receiving epidermal growth factor receptor-tyrosine kinase inhibitor treatments develop resistance. Although extensive studies have been applied to elucidate the underlying mechanisms, evidence is far from enough to establish a well-defined picture to correct resistance. In the review, we will discuss four different currently developed strategies that have the potential to overcome drug resistance in lung cancer therapies and facilitate prolonged anticancer effects of the first-line therapies.Keywords: ALK receptors cancer stem cell, chemotherapy, EGFR-TKI, target therapy, pharmacology, molecular biology, biotherapy

  8. Catalysis and Sulfa Drug Resistance in Dihydropteroate Synthase

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Mi-Kyung; Wu, Yinan; Li, Zhenmei; Zhao, Ying; Waddell, M. Brett; Ferreira, Antonio M.; Lee, Richard E.; Bashford, Donald; White, Stephen W. (SJCH)

    2013-04-08

    The sulfonamide antibiotics inhibit dihydropteroate synthase (DHPS), a key enzyme in the folate pathway of bacteria and primitive eukaryotes. However, resistance mutations have severely compromised the usefulness of these drugs. We report structural, computational, and mutagenesis studies on the catalytic and resistance mechanisms of DHPS. By performing the enzyme-catalyzed reaction in crystalline DHPS, we have structurally characterized key intermediates along the reaction pathway. Results support an S{sub N}1 reaction mechanism via formation of a novel cationic pterin intermediate. We also show that two conserved loops generate a substructure during catalysis that creates a specific binding pocket for p-aminobenzoic acid, one of the two DHPS substrates. This substructure, together with the pterin-binding pocket, explains the roles of the conserved active-site residues and reveals how sulfonamide resistance arises.

  9. 21 CFR 866.3950 - In vitro human immunodeficiency virus (HIV) drug resistance genotype assay.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false In vitro human immunodeficiency virus (HIV) drug... Serological Reagents § 866.3950 In vitro human immunodeficiency virus (HIV) drug resistance genotype assay. (a) Identification. The in vitro HIV drug resistance genotype assay is a device that consists of nucleic acid...

  10. Seasonal distribution of anti-malarial drug resistance alleles on the island of Sumba, Indonesia

    NARCIS (Netherlands)

    Asih, P.B.; Rogers, W.O.; Susanti, A.I.; Rahmat, A.; Rozi, I.E.; Kusumaningtyas, M.A.; Dewi, R.M.; Coutrier, F.N.; Sutamihardja, A.; Ven, A.J.A.M. van der; Sauerwein, R.W.; Syafruddin, D.

    2009-01-01

    BACKGROUND: Drug resistant malaria poses an increasing public health problem in Indonesia, especially eastern Indonesia, where malaria is highly endemic. Widespread chloroquine (CQ) resistance and increasing sulphadoxine-pyrimethamine (SP) resistance prompted Indonesia to adopt artemisinin-based com

  11. Conjugation to polymeric chains of influenza drugs targeting M2 ion channels partially restores inhibition of drug-resistant mutants

    OpenAIRE

    Larson, Alyssa M.; Chen, Jianzhu; Klibanov, Alexander M.

    2013-01-01

    By attaching multiple copies of the influenza M2 ion channel inhibitors amantadine (1) and rimantadine (2) to polymeric chains, we endeavored to recover their potency in inhibiting drug-resistant influenza viruses. Depending on loading densities, as well as the nature of the drug, the polymer, and the spacer arm, polymer-conjugated drugs were up to 30-fold more potent inhibitors of drug-resistant strains than their monomeric parents. In particular, a 20% loading density and a short linker gro...

  12. Drug delivery by a self-assembled DNA tetrahedron for overcoming drug resistance in breast cancer cells.

    Science.gov (United States)

    Kim, Kyoung-Ran; Kim, Da-Rae; Lee, Taemin; Yhee, Ji Young; Kim, Byeong-Su; Kwon, Ick Chan; Ahn, Dae-Ro

    2013-03-11

    A DNA tetrahedron is employed for efficient delivery of doxorubicin into drug-resistant breast cancer cells. The drug delivered with the DNA nanoconstruct is considerably cytotoxic, whereas free doxorubicin is virtually non-cytotoxic for the drug-resistant cells. Thus, the DNA tetrahedron, made of the inherently natural and biocompatible material, can be a good candidate for the drug carrier to overcome MDR in cancer cells.

  13. Repurposing Clinical Molecule Ebselen to Combat Drug Resistant Pathogens.

    Directory of Open Access Journals (Sweden)

    Shankar Thangamani

    Full Text Available Without a doubt, our current antimicrobials are losing the battle in the fight against newly-emerged multidrug-resistant pathogens. There is a pressing, unmet need for novel antimicrobials and novel approaches to develop them; however, it is becoming increasingly difficult and costly to develop new antimicrobials. One strategy to reduce the time and cost associated with antimicrobial innovation is drug repurposing, which is to find new applications outside the scope of the original medical indication of the drug. Ebselen, an organoselenium clinical molecule, possesses potent antimicrobial activity against clinical multidrug-resistant Gram-positive pathogens, including Staphylococcus, Streptococcus, and Enterococcus, but not against Gram-negative pathogens. Moreover, the activity of ebselen against Gram-positive pathogens exceeded those activities determined for vancomycin and linezolid, drugs of choice for treatment of Enterococcus and Staphylococcus infections. The minimum inhibitory concentrations of ebselen at which 90% of clinical isolates of Enterococcus and Staphylococcus were inhibited (MIC90 were found to be 0.5 and 0.25 mg/L, respectively. Ebselen showed significant clearance of intracellular methicillin-resistant S. aureus (MRSA in comparison to vancomycin and linezolid. We demonstrated that ebselen inhibits the bacterial translation process without affecting mitochondrial biogenesis. Additionally, ebselen was found to exhibit excellent activity in vivo in a Caenorhabditis elegans MRSA-infected whole animal model. Finally, ebselen showed synergistic activities with conventional antimicrobials against MRSA. Taken together, our results demonstrate that ebselen, with its potent antimicrobial activity and safety profiles, can be potentially used to treat multidrug resistant Gram-positive bacterial infections alone or in combination with other antibiotics and should be further clinically evaluated.

  14. OTYPIC CHARACTERIZATION AND ANTIFUNGAL SUSCEPTIBILITY PATTERN OF CANDIDA SP ISOLATED FROM A TERTIARY CARE CENTER

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    Rudramurthy

    2014-02-01

    Full Text Available ACT: Candida , a yeast like ubiquitous fungus , is an endogenous species which produces commonest fungal infection; Candidiasis. Resistance to antifungal agents is an alarming sign for the emerging common nosocomial candidiasis. MATERIALS AND METHODS: Various types of specimens we re collected from the c linically suspected cases of candidiasis. Isolation and characterization of candida sp . was done by standard procedures. Antifungal susceptibility was done by disc diffusion method. RESULT: The candida was isolated from various clinical specimens , vaginal swab (24.66% , skin scraping (13.33% oral swabs (12.66% , ear swabs ( 11.33% , nail scraping (10% , and pus from diabetes foot ulcer and post - operative wound infection ( 8% , sputum ( 6% , urine (4.66% , stool ( 4% , blood ( 2.66% , and eye swabs ( 2.66%. Amon g different species of candida isolated C.albicans was the predominant species (79.33% followed by C tropicalis (19.33% and C.Guilliermondii (1.33%. Antifungal resistance of different species of candida was higher to fluconazole . The least resistance wa s seen with amphotericin - B (1.33%. CONCLUSION: The increased isolation of candida species and development of resistance to commonly used antifungal drugs requires careful interpretation and the in vitro susceptibility testing. This facilitates better pat ient care.

  15. Transmission of extensively drug-resistant and multidrug resistant Mycobacterium tuberculosis in families identified by genotyping

    Institute of Scientific and Technical Information of China (English)

    YAN Li-ping; QIN Lian-hua; ZHANG Qing; SUN Hua; HAN Min; XIAO He-ping

    2013-01-01

    Background Diagnosis and appropriate treatment of multidrug-resistant tuberculosis (MDR-TB) remain major challenges.We sought to elucidate that persons who share a household with drug resistance tuberculosis patients are at high risk for primary drug resistance tuberculosis and how to prevent these outbreaks.Methods We used 12-locus mycobacterial interspersed repetitive unit and 7-locus variable-number tandem repeat to identify household transmission of extensively drug resistant and multiple drug resistant Mycobacterium tuberculosis in three families admitted in Shanghai Pulmonary Hospital affiliated with Tongji University.Drug susceptibility tests were done by the modified proportion method in the MGIT 960 system in the same time.Clinical data were also obtained from the subjects' medical records.Results All of the six strains were defined as Beijing genotype by the deletion-targeted multiplex PCR (DTM-PCR) identification on the genomic deletion RD105.Strains from family-1 had the same minisatellite interspersed repetitive unit (MIRU) pattem (232225172531) and the same MIRU pattern (3677235).Strains from family-2 had the same MIRU pattern (2212261553323) and the same MIRU pattern (3685134).Strains from family-3 did not have the same MIRU pattern and they differed at only one locus (223326173533,223325173533),and did not have the same VNTR pattern with two locus differed (3667233,3677234).Conclusions Household transmission exists in the three families.A clear chain of tuberculosis transmission within family exists.Tuberculosis susceptibility should be considered when there is more than one tuberculosis patients in a family.Household tuberculosis transmission could be prevented with adequate treatment of source patients.

  16. "DRUG RESISTANCE PATTERN IN ISOLATED BACTERIA FROM BLOOD CULTURES"

    Directory of Open Access Journals (Sweden)

    A. Sobhani

    2004-05-01

    Full Text Available Bacteremia is an important infectious disease which may lead to death. Common bacteria and pattern of antibiotic resistance in different communities are different and understanding these differences is important. In the present study, relative frequency and pattern of drug resistance have been examined in bacteria isolated from blood cultures in Razi Hospital laboratory. The method of the study was descriptive. Data collection was carried out retrospectively. Total sample consisted of 311 positive blood cultures from 1999 to 2001. Variables under study were bacterial strains, antibiotics examined in antibiogram, microbial resistance, and patients' age and sex. The most common isolated bacteria were Salmonella typhi (22.2% and the least common ones were Citrobacter (1.6%. The highest antibiotic resistance was seen against amoxicillin (88.4%. The proportion of males to females was1: 1/1 and the most common age group was 15-44 (47.3%. Common bacteria and pattern of antibiotic resistance were different in some areas and this subject requires further studies in the future.

  17. Comparative genomics of drug resistance in Trypanosoma brucei rhodesiense.

    Science.gov (United States)

    Graf, Fabrice E; Ludin, Philipp; Arquint, Christian; Schmidt, Remo S; Schaub, Nadia; Kunz Renggli, Christina; Munday, Jane C; Krezdorn, Jessica; Baker, Nicola; Horn, David; Balmer, Oliver; Caccone, Adalgisa; de Koning, Harry P; Mäser, Pascal

    2016-09-01

    Trypanosoma brucei rhodesiense is one of the causative agents of human sleeping sickness, a fatal disease that is transmitted by tsetse flies and restricted to Sub-Saharan Africa. Here we investigate two independent lines of T. b. rhodesiense that have been selected with the drugs melarsoprol and pentamidine over the course of 2 years, until they exhibited stable cross-resistance to an unprecedented degree. We apply comparative genomics and transcriptomics to identify the underlying mutations. Only few mutations have become fixed during selection. Three genes were affected by mutations in both lines: the aminopurine transporter AT1, the aquaporin AQP2, and the RNA-binding protein UBP1. The melarsoprol-selected line carried a large deletion including the adenosine transporter gene AT1, whereas the pentamidine-selected line carried a heterozygous point mutation in AT1, G430R, which rendered the transporter non-functional. Both resistant lines had lost AQP2, and both lines carried the same point mutation, R131L, in the RNA-binding motif of UBP1. The finding that concomitant deletion of the known resistance genes AT1 and AQP2 in T. b. brucei failed to phenocopy the high levels of resistance of the T. b. rhodesiense mutants indicated a possible role of UBP1 in melarsoprol-pentamidine cross-resistance. However, homozygous in situ expression of UBP1-Leu(131) in T. b. brucei did not affect the sensitivity to melarsoprol or pentamidine. PMID:26973180

  18. Multiple myeloma and persistence of drug resistance in the age of novel drugs (Review).

    Science.gov (United States)

    Krishnan, Sabna Rajeev; Jaiswal, Ritu; Brown, Ross D; Luk, Frederick; Bebawy, Mary

    2016-07-01

    Multiple myeloma (MM) is a mature B cell neoplasm that results in multi-organ failure. The median age of onset, diverse clinical manifestations, heterogeneous survival rate, clonal evolution, intrinsic and acquired drug resistance have impact on the therapeutic management of the disease. Specifically, the emergence of multidrug resistance (MDR) during the course of treatment contributes significantly to treatment failure. The introduction of the immunomodulatory agents and proteasome inhibitors has seen an increase in overall patient survival, however, for the majority of patients, relapse remains inevitable with evidence that these agents, like the conventional chemotherapeutics are also subject to the development of MDR. Clinical management of patients with MM is currently compromised by lack of a suitable procedure to monitor the development of clinical drug resistance in individual patients. The current MM prognostic measures fail to pick the clonotypic tumor cells overexpressing drug efflux pumps, and invasive biopsy is insufficient in detecting sporadic tumors in the skeletal system. This review summarizes the challenges associated with treating the complex disease spectrum of myeloma, with an emphasis on the role of deleterious multidrug resistant clones orchestrating relapse. PMID:27175906

  19. Synthesis of Antifungal Drug Amorolfine Hydrochloride%抗真菌药盐酸阿莫罗芬的合成研究

    Institute of Scientific and Technical Information of China (English)

    王兴旺; 张珩; 杨艺虹; 张秀兰; 曾威

    2012-01-01

    Antifungal drug amorolfine hydrochloride was synthesized starting from formaldehyde and propanal via the processes of Mannich reaction, Friedel -Crafts reaction, saponification, condensation, reduction and salification. The affecting factors including the ratio of the raw materials, the reaction time, the reaction temperature and the catalyst were investigated. The product was prepared in an overall yield of 30.97%, and the structure was confirmed with IR, GC-MS and 'H NMR.%以甲醛和丙醛为原料,经Mannich反应、Friedel-Crafts烷基化、Saponification反应、缩合、还原、成盐反应合成抗真菌药盐酸阿莫罗芬.对影响收率的原料配比、反应时间、反应温度和催化剂等因素进行了工艺优化.通过IR、GC-MS、1H NMR确证了盐酸阿莫罗芬结构.其工艺简单、原料易得、条件温和、操作简便,总收率达30.97%(以丙醛计),具有工业化应用前景.

  20. Candida albicans AGE3, the ortholog of the S. cerevisiae ARF-GAP-encoding gene GCS1, is required for hyphal growth and drug resistance.

    Directory of Open Access Journals (Sweden)

    Thomas Lettner

    Full Text Available BACKGROUND: Hyphal growth and multidrug resistance of C. albicans are important features for virulence and antifungal therapy of this pathogenic fungus. METHODOLOGY/PRINCIPAL FINDINGS: Here we show by phenotypic complementation analysis that the C. albicans gene AGE3 is the functional ortholog of the yeast ARF-GAP-encoding gene GCS1. The finding that the gene is required for efficient endocytosis points to an important functional role of Age3p in endosomal compartments. Most C. albicans age3Delta mutant cells which grew as cell clusters under yeast growth conditions showed defects in filamentation under different hyphal growth conditions and were almost completely disabled for invasive filamentous growth. Under hyphal growth conditions only a fraction of age3Delta cells shows a wild-type-like polarization pattern of the actin cytoskeleton and lipid rafts. Moreover, age3Delta cells were highly susceptible to several unrelated toxic compounds including antifungal azole drugs. Irrespective of the AGE3 genotype, C-terminal fusions of GFP to the drug efflux pumps Cdr1p and Mdr1p were predominantly localized in the plasma membrane. Moreover, the plasma membranes of wild-type and age3Delta mutant cells contained similar amounts of Cdr1p, Cdr2p and Mdr1p. CONCLUSIONS/SIGNIFICANCE: The results indicate that the defect in sustaining filament elongation is probably caused by the failure of age3Delta cells to polarize the actin cytoskeleton and possibly of inefficient endocytosis. The high susceptibility of age3Delta cells to azoles is not caused by inefficient transport of efflux pumps to the cell membrane. A possible role of a vacuolar defect of age3Delta cells in drug susceptibility is proposed and discussed. In conclusion, our study shows that the ARF-GAP Age3p is required for hyphal growth which is an important virulence factor of C. albicans and essential for detoxification of azole drugs which are routinely used for antifungal therapy. Thus, it

  1. Definition of drug-resistant epilepsy: is it evidence based?

    Science.gov (United States)

    Wiebe, Samuel

    2013-05-01

    Clinical case definitions are the cornerstone of clinical communication and of clinical and epidemiologic research. The ramifications of establishing a case definition are extensive, including potentially large changes in epidemiologic estimates of frequency, and decisions for clinical management. Yet, defining a condition entails numerous challenges such as defining the scope and purpose, incorporating the strongest evidence base with clinical expertise, accounting for patients' values, and considering impact on care. The clinical case definition of drug-resistant epilepsy, in addition, must address what constitutes an adequate intervention for an individual drug, what are the outcomes of relevance, what period of observation is sufficient to determine success or failure, how many medications should be tried, whether seizure frequency should play a role, and what is the role of side effects and tolerability. On the other hand, the principles of evidence-based medicine (EBM) aim at providing a systematic approach to incorporating the best available evidence into the process of clinical decision for individual patients. The case definition of drug-resistant epilepsy proposed by the the International League Against Epilepsy (ILAE) in 2009 is evaluated in terms of the principles of EBM as well as the stated goals of the authors of the definition.

  2. Pharmacogenomic association study on the role of drug metabolizing, drug transporters and drug target gene polymorphisms in drug-resistant epilepsy in a north Indian population

    OpenAIRE

    Ritu Kumari; Ram Lakhan; Garg, R. K.; Kalita, J; Misra, U K; Balraj Mittal

    2011-01-01

    Background: In epilepsy, in spite of the best possible medications and treatment protocols, approximately one-third of the patients do not respond adequately to anti-epileptic drugs. Such interindividual variations in drug response are believed to result from genetic variations in candidate genes belonging to multiple pathways. Materials and Methods: In the present pharmacogenetic analysis, a total of 402 epilepsy patients were enrolled. Of them, 128 were diagnosed as multiple drug-resist...

  3. Drug sensitivity and drug resistance profiles of human intrahepatic cholangiocarcinoma cell lines

    Institute of Scientific and Technical Information of China (English)

    Nisana Tepsiri; Liengchai Chaturat; Banchob Sripa; Wises Namwat; Sopit Wongkham; Vajarabhongsa Bhudhisawasdi; Wichittra Tassaneeyakul

    2005-01-01

    AIM: To study the effect of a number of chemotherapeutic drugs on five human intrahepatic cholangiocarcinoma (CCA) cell lines. The expressions of genes that have been proposed to influence the resistance of chemotherapeutic drugs including thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), glutathione-S-transferase P1 (GSTP1), multidrug resistance protein (MDR1) and multidrug resistance-associated proteins (MRPs) were also determined.METHODS: Five human CCA cell lines (KKU-100, KKU M055, KKU-M156, KKU-M214 and KKU-OCA17) weretreated with various chemotherapeutic drugs and growth inhibition was determined by 3-(4,5-dimethylthiazol-2-yl)5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Semi-quantitative levels of gene expression were determined by a reverse transcriptase polymerase chain reaction (RT-PCR). Results of IC50 values and the ratios of gene expression were analyzed by linear regression to predict their relationship. RESULTS: Among five CCA cell lines, KKU-M055 was the most sensitive cell line towards all chemotherapeutic drugs investigated, particularly taxane derivatives with IC50 values of 0.02-3 nmol/L, whereas KKU-100 was apparently the least sensitive cell line. When compared to other chemotherapeutic agents, doxorubicin and pirarubicin showed the lowest IC50 values (<5 μmol/L) in all five CCA cell lines. Results from RT-PCR showed that TS, MRP1, MRP3 and GSTP1 were highly expressed in these five CCA cell lines while DPD and MRP2 were only moderately expressed. It should be noted that MDR1 expression was detected only in KKU-OCA17 cell lines. A strong correlation was only found between the level of MRP3 expression and the IC50 values of etoposide, doxorubicin and pirarubicin (r = 0.86-0.98, ,P<0.05). CONCLUSION: Sensitivity to chemotherapeutic agents is not associated with the histological type of CCA. Choosing of the appropriate chemotherapeutic regimen for the treatment of CCA requires knowledge of drug

  4. Antifungal activity of topical microemulsion containing a thiophene derivative

    Directory of Open Access Journals (Sweden)

    Geovani Pereira Guimarães

    2014-06-01

    Full Text Available Fungal infections have become a major problem of worldwide concern. Yeasts belonging to the Candida genus and the pathogenic fungus Cryptococcus neoformans are responsible for different clinical manifestations, especially in immunocompromised patients. Antifungal therapies are currently based on a few chemotherapeutic agents that have problems related to effectiveness and resistance profiles. Microemulsions are isotropic, thermodynamically stable transparent systems of oil, water and surfactant that can improve the solubilization of lipophilic drugs. Taking into account the need for more effective and less toxic drugs along with the potential of thiophene derivatives as inhibitors of pathogenic fungi growth, this study aimed to evaluate the antifungal activity of a thiophene derivative (5CN05 embedded in a microemulsion (ME. The minimum inhibitory concentration (MIC was determined using the microdilution method using amphotericin B as a control. The formulations tested (ME- blank and ME-5CN05 showed physico-chemical properties that would allow their use by the topical route. 5CN05 as such exhibited moderate or weak antifungal activity against Candida species (MIC = 270-540 µg.mL-1 and good activity against C. neoformans (MIC = 17 µg.mL-1. Candida species were susceptible to ME-5CN05 (70-140 µg.mL-1, but C. neoformans was much more, presenting a MIC value of 2.2 µg.mL-1. The results of this work proved promising for the pharmaceutical industry, because they suggest an alternative therapy against C. neoformans.

  5. Drug resistance. K13-propeller mutations confer artemisinin resistance in Plasmodium falciparum clinical isolates.

    Science.gov (United States)

    Straimer, Judith; Gnädig, Nina F; Witkowski, Benoit; Amaratunga, Chanaki; Duru, Valentine; Ramadani, Arba Pramundita; Dacheux, Mélanie; Khim, Nimol; Zhang, Lei; Lam, Stephen; Gregory, Philip D; Urnov, Fyodor D; Mercereau-Puijalon, Odile; Benoit-Vical, Françoise; Fairhurst, Rick M; Ménard, Didier; Fidock, David A

    2015-01-23

    The emergence of artemisinin resistance in Southeast Asia imperils efforts to reduce the global malaria burden. We genetically modified the Plasmodium falciparum K13 locus using zinc-finger nucleases and measured ring-stage survival rates after drug exposure in vitro; these rates correlate with parasite clearance half-lives in artemisinin-treated patients. With isolates from Cambodia, where resistance first emerged, survival rates decreased from 13 to 49% to 0.3 to 2.4% after the removal of K13 mutations. Conversely, survival rates in wild-type parasites increased from ≤0.6% to 2 to 29% after the insertion of K13 mutations. These mutations conferred elevated resistance to recent Cambodian isolates compared with that of reference lines, suggesting a contemporary contribution of additional genetic factors. Our data provide a conclusive rationale for worldwide K13-propeller sequencing to identify and eliminate artemisinin-resistant parasites.

  6. Combined drug medium with isoniazid and rifampicin for identification of multi-drug resistant Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Nalini S

    2010-01-01

    Full Text Available A low-cost method of detecting multi-drug resistant Mycobacterium tuberculosis (MDR-TB with the possibility of quick adoption in a resource limited setting is urgently required. We conducted a study combining isoniazid and rifampicin in a single LJ medium, to detect MDR-TB strains. Combined and individual drug media showed 100% concordance for the detection of MDR-TB and susceptible strains by proportion method. Considering the results, combined isoniazid and rifampicin containing medium could be considered for use in settings where the sole detection of MDR-TB strains is justified.

  7. Probiotics as Antifungals in Mucosal Candidiasis.

    Science.gov (United States)

    Matsubara, Victor H; Bandara, H M H N; Mayer, Marcia P A; Samaranayake, Lakshman P

    2016-05-01

    Candidais an opportunistic pathogen that causes mucosal and deep systemic candidiasis. The emergence of drug resistance and the side effects of currently available antifungals have restricted their use as long-term prophylactic agents for candidal infections. Given this scenario, probiotics have been suggested as a useful alternative for the management of candidiasis. We analyzed the available data on the efficacy of probiotics in candidal colonization of host surfaces. A number of well-controlled studies indicate that probiotics, particularly lactobacilli, suppressCandidagrowth and biofilm development in vitro.A few clinical trials have also shown the beneficial effects of probiotics in reducing oral, vaginal, and enteric colonization byCandida; alleviation of clinical signs and symptoms; and, in some cases, reducing the incidence of invasive fungal infection in critically ill patients. Probiotics may serve in the future as a worthy ally in the battle against chronic mucosal candidal infections. PMID:26826375

  8. Positron emission tomography in patients with drug-resistant epilepsy

    International Nuclear Information System (INIS)

    Positron emission tomography with 18Fluor-deoxyglucose (18FDG PET) was introduced as method of evaluation of the cerebral metabolism in the early 80s. 18FDG PET/computed tomography (PET/CT) has rapidly become a method of epileptogenic zone localization because of the hypometaboilsm of this zone during the interictal period. This paper represents the first Bulgarian series of patients with drug- resistant epilepsy who were evaluated with 18FDG PET as part of the presurgical work-up. Our study has included 21 patients with drug-resistant epilepsy who were evaluated with 18FDG PET/CT from January 2010 to May 2013. All patients were evaluated with dedicated MRI epilepsy protocol. PET/CT study was fused with 3D MRI study using FSL or GE software. Video EEG monitoring was performed in all 21 patients and seizures were recorded in 18 patients. Hypometabolic zones were found in 15 patients. The hypometabolism was focal in 5 patients, multilobar in 9 patients and hemispheric in 1 patient. The MRI was normal in 8 patients. Hypometabolic zones were found in 3 of these 8 patients with cryptogenic epilepsy. Epilepsy surgery was performed in 6 cases. All operated patients were with hypometabolic zones. Significant seizure reduction after surgery was observed in 5 of 6 operated patients. 18FDG PET/CT is a valuable method for epileptogenic zone localization in patients with drug-resistant epilepsy. The introduction of this method in the bulgarian epilepsy surgery program increases the chances for successful resective surgery. (authors)

  9. Structure-Functional Characterization of Cytochrome P450 Sterol 14α-Demethylase (CYP51B) from Aspergillus fumigatus and Molecular Basis for the Development of Antifungal Drugs.

    Science.gov (United States)

    Hargrove, Tatiana Y; Wawrzak, Zdzislaw; Lamb, David C; Guengerich, F Peter; Lepesheva, Galina I

    2015-09-25

    Aspergillus fumigatus is the opportunistic fungal pathogen that predominantly affects the immunocompromised population and causes 600,000 deaths/year. The cytochrome P450 51 (CYP51) inhibitor voriconazole is currently the drug of choice, yet the treatment efficiency remains low, calling for rational development of more efficient agents. A. fumigatus has two CYP51 genes, CYP51A and CYP51B, which share 59% amino acid sequence identity. CYP51B is expressed constitutively, whereas gene CYP51A is reported to be inducible. We expressed, purified, and characterized A. fumigatus CYP51B, including determination of its substrate preferences, catalytic parameters, inhibition, and x-ray structure in complexes with voriconazole and the experimental inhibitor (R)-N-(1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethyl)-4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamide (VNI). The enzyme demethylated its natural substrate eburicol and the plant CYP51 substrate obtusifoliol at steady-state rates of 17 and 16 min(-1), respectively, but did not metabolize lanosterol, and the topical antifungal drug miconazole was the strongest inhibitor that we identified. The x-ray crystal structures displayed high overall similarity of A. fumigatus CYP51B to CYP51 orthologs from other biological kingdoms but revealed phylum-specific differences relevant to enzyme catalysis and inhibition. The complex with voriconazole provides an explanation for the potency of this relatively small molecule, whereas the complex with VNI outlines a direction for further enhancement of the efficiency of this new inhibitory scaffold to treat humans afflicted with filamentous fungal infections. PMID:26269599

  10. Predicting drug resistance of the HIV-1 protease using molecular interaction energy components

    OpenAIRE

    Hou, Tingjun; Zhang, Wei; Wang, Jian; Wang, Wei

    2009-01-01

    Drug resistance significantly impairs the efficacy of AIDS therapy. Therefore, precise prediction of resistant viral mutants is particularly useful for developing effective drugs and designing therapeutic regimen. In this study, we applied a structure-based computational approach to predict mutants of the HIV-1 protease resistant to the seven FDA approved drugs. We analyzed the energetic pattern of the protease-drug interaction by calculating the molecular interaction energy components (MIECs...

  11. Studies of overcoming acquired resistance : molecular mechanisms and development of novel drugs

    OpenAIRE

    Wang, Xin

    2014-01-01

    Chemotherapeutic agents have become widely applied for treatment of various types of malignancies. Drug resistance unfortunately remains as a major obstacle for the effectiveness of chemotherapy. Cancer drug resistance includes two broad categories: intrinsic and acquired. In this thesis I have examined the problem of acquired drug resistance and have aimed to develop novel approaches to overcome acquired resistance. Clofarabine is a second-generation nucleoside analogue which has been ...

  12. Outcome after hemispherectomy in patients with drug-resistant epilepsy

    Directory of Open Access Journals (Sweden)

    Wei-wei WANG

    2015-11-01

    Full Text Available Hemispherectomy, as well as hemispherotomy, is an effective treatment for children and adolescents with drug-resistant epilepsy. The procedure is considered in children and adolescents with hemispheric damage due to congenital (e.g. malformation of cortical development, acquired (e.g. perinatal cerebral infarction or progressive diseases (e.g. Rasmussen encephalitis. As the main objective of this procedure, seizure control can be achieved in up to 80% of selected cases. Besides, the cognitive and motor function as well as the quality of life has shown good outcome. DOI: 10.3969/j.issn.1672-6731.2015.11.016

  13. Plasmonic Nanobubbles Rapidly Detect and Destroy Drug-Resistant Tumors

    Directory of Open Access Journals (Sweden)

    Ekaterina Y. Lukianova-Hleb, Xiaoyang Ren, Debra Townley, Xiangwei Wu, Michael E. Kupferman, Dmitri O. Lapotko

    2012-01-01

    Full Text Available The resistance of residual cancer cells after oncological resection to adjuvant chemoradiotherapies results in both high recurrence rates and high non-specific tissue toxicity, thus preventing the successful treatment of such cancers as head and neck squamous cell carcinoma (HNSCC. The patients' survival rate and quality of life therefore depend upon the efficacy, selectivity and low non-specific toxicity of the adjuvant treatment. We report a novel, theranostic in vivo technology that unites both the acoustic diagnostics and guided intracellular delivery of anti-tumor drug (liposome-encapsulated doxorubicin, Doxil in one rapid process, namely a pulsed laser-activated plasmonic nanobubble (PNB. HNSCC-bearing mice were treated with gold nanoparticle conjugates, Doxil, and single near-infrared laser pulses of low energy. Tumor-specific clusters of gold nanoparticles (solid gold spheres converted the optical pulses into localized PNBs. The acoustic signals of the PNB detected the tumor with high specificity and sensitivity. The mechanical impact of the PNB, co-localized with Doxil liposomes, selectively ejected the drug into the cytoplasm of cancer cells. Cancer cell-specific generation of PNBs and their intracellular co-localization with Doxil improved the in vivo therapeutic efficacy from 5-7% for administration of only Doxil or PNBs alone to 90% thus demonstrating the synergistic therapeutic effect of the PNB-based intracellular drug release. This mechanism also reduced the non-specific toxicity of Doxil below a detectable level and the treatment time to less than one minute. Thus PNBs combine highly sensitive diagnosis, overcome drug resistance and minimize non-specific toxicity in a single rapid theranostic procedure for intra-operative treatment.

  14. Low-level quinolone-resistance in multi-drug resistant typhoid

    International Nuclear Information System (INIS)

    To find out the frequency of low-level quinolone-resistance in Multi-Drug Resistant (MDR) typhoid using nalidixic acid screening disc. Blood was obtained from suspected cases of typhoid fever and cultured in to BacT/ALERT. The positive blood cultures bottles were subcultured. The isolates were identified by colony morphology and biochemical tests using API-20E galleries. Susceptibility testing of isolates was done by modified Kirby-Bauer disc diffusion method on Muellar Hinton Agar. For the isolates, which were resistant to nalidixic acid by disc diffusion method, Minimal Inhibitory Concentrations (MICs) of ciprofloxacin and nalidixic acid were determined by using the E-test strips. Disc diffusion susceptibility tests and MICs were interpreted according to the guidelines provided by National Committee for Control Laboratory Standard (NCCLS). A total of 21(65.5%) out of 32 isolates of Salmonellae were nalidixic acid-resistant by disk diffusion method. All the nalidixic acid-resistant isolates by disc diffusion method were confirmed by MICs for both ciprofloxacin and nalidixic acid. All the nalidixic acid-resistant isolates had a ciprofloxacin MIC of 0.25-1 microg/ml (reduced susceptibility) and nalidixic acid MICs > 32 microg (resistant). Out of all Salmonella isolates, 24 (75%) were found to be MDR, and all were S. typbi. Low-level quinolone-resistance in typhoid was high in this small series. Screening for nalidixic acid resistance with a 30 microg nalidixic acid disk is a reliable and cost-effective method to detect low-level fluoroquinolone resistance, especially in the developing countries. (author)

  15. 含有额外拷贝黄曲霉cyp51同源基因的烟曲霉对抗真菌药物的敏感性测定%Antifungal susceptibility of the A.fumigatus transformants containing extra copies of A.flavus cyp51 gene homologues to the common antifungal drugs

    Institute of Scientific and Technical Information of China (English)

    刘伟霞; 孙毅; 万喆; 李若瑜; 刘伟

    2011-01-01

    Objective To investigate the effect of Aspergillus flavus cyp51 genes on antifungal susceptibility by cloning and constucting the extra copies of Aspergillus flavus cyp51 genes. Methods A.flavus cyp5l gene homologues were identified by tblastn searches inA. flavus genome database. PCR fragments composed of the 5'flanking sequence (approximately 1 000 bp) ofcyp51 ,cyp51 ORF, and its 3'flanking sequence (approximately 1 000 bp), were subcloned into shuttle plasmid pRG3-AMAl-NotI to produce recombinant plasmids. These plasmids and empty plasmid pRG3-AMA1-Notl were transformed into A.fumigatus strain AF293.1 (pyrG-) respectively to produce transformants. The Clinical Laboratory Standard Institute broth microdilution method M38-A2 and E-test method were used to assay the minimal inhibitory concentrations (MICs) of itraconazole ( ITC), voriconazole ( VRC), amphotericin B (AMB), and posaconazole (POS), or minimal effect concentration (MEC) of caspofungin (CAS), against these transformants. Results A. flavus genome contains three cyp51 gene homologues, cyp51A ,cyp51B and cyp51 C, of which the ORF size are 1 400-2 000 bp. When these genes were subcloned into shuttle plasmid pRG3-AMA1-NotI, we get plasmids pRG3-AMA1-CYP51 A, pRG3-AMA1-CYP51B and pRG3-AMA1-CYP51C. These plasmids and empty plasmid were transformed into A.fumigatus strain AF293.1 (pyrG-) to produce transformants rCYP51A, rCYP51B, rCYP51C and rpRG. The antifungal susceptibility of these A.fumigatus transformants to the antifungal drugs by broth microdilution assaying and E-test method showed that, rCYP51A and rCYP51B were cross-resistant to VRC and ITC, susceptible to both AM B and CAS; rCYP51C and rpRG were intermediate to ITC and VRC, susceptible to both A MB and CAS. Conclusion In A. fumigatus , extra copies of A.flavus ' cyp51A gene or cyp51B gene have effect on antifungal susceptibility to azoles, have no effect on AMB and CAS. Extra copy ofcyp51C has no obvious effect on all the tested drugs.%目的

  16. Extensively and Pre-Extensively Drug Resistant Tuberculosis in Clinical Isolates of Multi-Drug Resistant Tuberculosis Using Classical Second Line Drugs (Levofloxacin and Amikacin)

    International Nuclear Information System (INIS)

    Objective:To find out the frequency of Extensively Drug Resistant (XDR) and pre-XDR tuberculosis in clinical isolates of Multi-Drug Resistant (MDR) Tuberculosis (TB) by determining the susceptibilities against Levofloxacin and Amikacin (classical second line antituberculosis drugs). Study Design: A descriptive cross-sectional study. Place and Duration of Study: Microbiology Department, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from September 2011 to August 2013. Methodology: Amikacin (AK) and Levofloxacin (LEVO) were obtained in chemically pure form from Sigma (Taufkirchen, Germany). The breakpoint concentration used for AK was 1.0 micro g/ml and for LEVO 2.0 micro g/ml. Mycobacterial Growth Indicator Tube (MGIT) 960 system was used to carry out drug susceptibility testing as per recommended protocol. Results: A total of 3 MDR-TB isolates (3 percentage) turned out to be XDR-TB based upon simultaneous resistance to injectable second line antituberculosis drug AK and one of the fluoro-quinolones (LEVO). A total of 24 MDR-TB isolates (24 percentage) were found to be pre-XDR based upon resistance to LEVO alone. Treatment status record of patients with XDR and pre-XDRTB isolates revealed that majority of patients had received fluoroquinolones (FQs) during the course of treatment. Conclusion: XDR-TB has started to emerge in MDR-TB isolates in our set up. The worrying sign is the high frequency of pre-XDR tuberculosis. Urgent steps need to be taken to stem the tide of pre-XDR-TB in our population. It is thus recommended to develop facilities to carry out drug susceptibility testing to monitor the status of pre-XDR and XDR-TB in our population. (author)

  17. Spectrum and the In Vitro Antifungal Susceptibility Pattern of Yeast Isolates in Ethiopian HIV Patients with Oropharyngeal Candidiasis

    Directory of Open Access Journals (Sweden)

    Birhan Moges

    2016-01-01

    Full Text Available Background. In Ethiopia, little is known regarding the distribution and the in vitro antifungal susceptibility profile of yeasts. Objective. This study was undertaken to determine the spectrum and the in vitro antifungal susceptibility pattern of yeasts isolated from HIV infected patients with OPC. Method. Oral pharyngeal swabs taken from oral lesions of study subjects were inoculated onto Sabouraud Dextrose Agar. Yeasts were identified by employing conventional test procedures and the susceptibility of yeasts to antifungal agents was evaluated by disk diffusion assay method. Result. One hundred and fifty-five yeast isolates were recovered of which 91 isolates were from patients that were not under HAART and 64 were from patients that were under HAART. C. albicans was the most frequently isolated species followed by C. glabrata, C. tropicalis, C. krusei, C. kefyr, Cryptococcus laurentii, and Rhodotorula species. Irrespective of yeasts isolated and identified, 5.8%, 5.8%, 12.3%, 8.4%, 0.6%, and 1.3% of the isolates were resistant to amphotericin B, clotrimazole, fluconazole, ketoconazole, miconazole, and nystatin, respectively. Conclusion. Yeast colonization rate of 69.2% and 31% resistance to six antifungal agents was documented. These highlight the need for nationwide study on the epidemiology of OPC and resistance to antifungal drugs.

  18. In vitro study of the antifungal potential of Lamiaceae hydroalcoholic extracts against Candida species

    OpenAIRE

    Martins, Natália; Ferreira, Isabel C.F.R.; Barros, Lillian; Henriques, Mariana; Silva, Sónia

    2014-01-01

    The use of medicinal plants is an ancient practice, but recently there is an increasing interest towards the evaluation of their bioactive properties. Opportunistic fungal infections, linked with higher rates of fungal resistance to the current antifungal drugs, have deserved special relevance in the last decades. Candida albicans was identified as the main responsible agent for those infections, but other non-Candida albicans Candida (NCAC) species have been also found [1]. Thus,...

  19. In vitro study of the antifungal potential of Apiaceae hydroalcoholic extracts against Candida species

    OpenAIRE

    Martins, Natália; Ferreira, Isabel C.F.R.; Barros, Lillian; Henriques, Mariana; Silva, Sónia Carina

    2014-01-01

    The use of medicinal plants is an ancient practice, but recently there is an increasing interest towards the evaluation of their bioactive properties. Opportunistic fungal infections, linked with higher rates of fungal resistance to the current antifungal drugs, have deserved special relevance in the last decades. Candida albicans was identified as the main responsible agent for those infections, but other non-Candida albicans Candida (NCAC) species have been also found [1]. Thus, it is urgen...

  20. Salicylic acid in the induction of resistance to beet seedling damping-off and antifungal activity against Fusarium sp., in vitro

    Directory of Open Access Journals (Sweden)

    Douglas Junior Bertoncelli

    2016-02-01

    Full Text Available The damping off is the main disease that affects the beet crop during the seedling production. The aim of this study was to evaluate different salicylic acid (SA concentrations for resistance induction against damping-off in beet seedling and its antifungal activity against Fusarium sp., in vitro condition. Treatment of beet seed was with SA solution by immersion during 5 minutes in the 0.5, 1.0, 1.5 and 2.0 mM concentrations and control (distilled water. It was used four replications with 20 cells by experimental unit. The experiment was carried out for 14 days in cultivate chamber with temperature (23 oC ± 2°C, lighting (12 hours photoperiod and humidity (70% ± 10% controlled. After this time, the germination, damping off incidence, seedling length and fresh mass matter weight were evaluated. It was evaluated also in the seedling tissue the phenylalanine ammonia-lyase (PAL, ?-1.3 glucanase and chitinase level enzymes. In the in vitro the SA was putted in PDA (potato-dextrose-agar medium, where the Fusarium sp. mycelial growth was evaluated. The SA applied for seeds treatment didn’t had effect significant on damping off of beet seedlings, but it induced the activity of ?-1.3 glucanase enzyme, it being this higher in nine times when compared the treatment control. The SA acted in the Fusarium sp. in vitro control with fungitoxic action, suppressed mycelial growth in 28% if compared to control.

  1. A genomic and evolutionary approach reveals non-genetic drug resistance in malaria

    OpenAIRE

    Herman, Jonathan D.; Rice, Daniel P.; Ribacke, Ulf; Silterra, Jacob; Deik, Amy A.; Moss, Eli L; Broadbent, Kate M; Neafsey, Daniel E; Desai, Michael M; Clish, Clary B.; Mazitschek, Ralph; Wirth, Dyann F.

    2014-01-01

    Background Drug resistance remains a major public health challenge for malaria treatment and eradication. Individual loci associated with drug resistance to many antimalarials have been identified, but their epistasis with other resistance mechanisms has not yet been elucidated. Results We previously described two mutations in the cytoplasmic prolyl-tRNA synthetase (cPRS) gene that confer resistance to halofuginone. We describe here the evolutionary trajectory of halofuginone resistance of tw...

  2. Species distribution & antifungal susceptibility pattern of oropharyngeal Candida isolates from human immunodeficiency virus infected individuals

    Directory of Open Access Journals (Sweden)

    Partha Pratim Das

    2016-01-01

    Results: From the 59 culture positive HIV seropositive cases, 61 Candida isolates were recovered; Candidaalbicans (n=47, 77.0%, C. dubliniensis (n=9, 14.7%, C. parapsilosis (n=2, 3.2%, C. glabrata (n=2, 3.2%, and C. famata (n=1, 1.6%. Candida colonization in HIV-seropositive individuals was significantly higher than that of HIV-seronegative (control group. Antifungal susceptibility testing revealed (n=6, 9.3% C. albicans isolates resistant to voriconazole and fluconazole by disk-diffusion method whereas no resistance was seen by Fungitest method. Interpretation & conclusions: C. albicans was the commonest Candida species infecting or colonizing HIV seropositive individuals. Oropharyngeal Candida isolates had high level susceptibility to all the major antifungals commonly in use. Increased level of immunosuppression in HIV-seropositives and drug resistance of non-albicans Candida species makes identification and susceptibility testing of Candida species necessary in different geographical areas of the country.

  3. Adaptive and Mutational Resistance: Role of Porins and Efflux Pumps in Drug Resistance

    OpenAIRE

    Fernández, Lucía; Robert E W Hancock

    2012-01-01

    Summary: The substantial use of antibiotics in the clinic, combined with a dearth of new antibiotic classes, has led to a gradual increase in the resistance of bacterial pathogens to these compounds. Among the various mechanisms by which bacteria endure the action of antibiotics, those affecting influx and efflux are of particular importance, as they limit the interaction of the drug with its intracellular targets and, consequently, its deleterious effects on the cell. This review evaluates t...

  4. Surgical management of cavernous malformations coursing with drug resistant epilepsy

    Directory of Open Access Journals (Sweden)

    Mario Arturo Alonso-Vanegas

    2012-01-01

    Full Text Available Cerebral cavernous malformations (CM are dynamic lesions characterized by continuous size changes and repeated bleeding. When involving cortical tissue, CM pose a significant risk for the development of drug-resistant epilepsy, which is thought to be result of an altered neuronal network caused by the lesion itself and its blood degradation products. Preoperative evaluation should comprise a complete seizure history, neurological examination, epilepsy-oriented MRI, EEG, video-EEG, completed with SPECT, PET, functional MRI and/or invasive monitoring as needed. Radiosurgery shows variable rates of seizure freedom and a high incidence of complications, thus microsurgical resection remains the optimal treatment for CM coursing with drug-resistant epilepsy.Two thirds of patients reach Engel I class at three-year follow-up, regardless of lobar location. Those with secondarily generalized seizures, a higher seizure frequency, and generalized abnormalities on preoperative or postoperative EEG, show poorer outcomes, while factors such as gender, duration of epilepsy, lesion size, age, bleeding at the time of surgery, do not correlate consistently with seizure outcome. Electrocorticography and a meticulous removal of all cortical hemosiderin –beyond pure lesionectomy– reduce the risk of symptomatic recurrences.

  5. Yeast cells with impaired drug resistance accumulate glycerol and glucose.

    Science.gov (United States)

    Dikicioglu, Duygu; Oc, Sebnem; Rash, Bharat M; Dunn, Warwick B; Pir, Pınar; Kell, Douglas B; Kirdar, Betul; Oliver, Stephen G

    2014-01-01

    Multiple drug resistance (MDR) in yeast is effected by two major superfamilies of membrane transporters: the major facilitator superfamily (MFS) and the ATP-binding cassette (ABC) superfamily. In the present work, we investigated the cellular responses to disruptions in both MFS (by deleting the transporter gene, QDR3) and ABC (by deleting the gene for the Pdr3 transcription factor) transporter systems by growing diploid homozygous deletion yeast strains in glucose- or ammonium-limited continuous cultures. The transcriptome and the metabolome profiles of these strains, as well as the flux distributions in the optimal solution space, reveal novel insights into the underlying mechanisms of action of QDR3 and PDR3. Our results show how cells rearrange their metabolism to cope with the problems that arise from the loss of these drug-resistance genes, which likely evolved to combat chemical attack from bacterial or fungal competitors. This is achieved through the accumulation of intracellular glucose, glycerol, and inorganic phosphate, as well as by repurposing genes that are known to function in other parts of metabolism in order to minimise the effects of toxic compounds. PMID:24157722

  6. Multidrug-resistant and extensively drug-resistant tuberculosis: a review of current concepts and future challenges.

    Science.gov (United States)

    Günther, Gunar

    2014-06-01

    Multidrug-resistant and extensively drug-resistant tuberculosis are recent global health issues, which makes tuberculosis - after the success of short course treatment during the second half of the last century - a major health challenge. Globalisation, health inequalities, competing economic interests and political instability contribute substantially to the spread of drug-resistant strains, which are associated with high rates of morbidity and mortality. Issues such as increasing transmission of drug-resistant strains, poor diagnostic coverage and a lengthy, toxic treatment need to be overcome by innovative approaches to tuberculosis control, prevention, diagnostics and treatment. This review addresses recent developments and future concepts.

  7. Synthesis, Structure-Activity Relationships (SAR and in Silico Studies of Coumarin Derivatives with Antifungal Activity

    Directory of Open Access Journals (Sweden)

    José M. Barbosa-Filho

    2013-01-01

    Full Text Available The increased incidence of opportunistic fungal infections, associated with greater resistance to the antifungal drugs currently in use has highlighted the need for new solutions. In this study twenty four coumarin derivatives were screened in vitro for antifungal activity against strains of Aspergillus. Some of the compounds exhibited significant antifungal activity with MICs values ranging between 16 and 32 µg/mL. The structure-activity relationships (SAR study demonstrated that O-substitutions are essential for antifungal activity. It also showed that the presence of a short aliphatic chain and/or electron withdrawing groups (NO2 and/or acetate favor activity. These findings were confirmed using density functional theory (DFT, when calculating the LUMO density. In Principal Component Analysis (PCA, two significant principal components (PCs explained more than 60% of the total variance. The best Partial Least Squares Regression (PLS model showed an r2 of 0.86 and q2cv of 0.64 corroborating the SAR observations as well as demonstrating a greater probe N1 interaction for active compounds. Descriptors generated by TIP correlogram demonstrated the importance of the molecular shape for antifungal activity.

  8. [Progress in researches on molecular markers of Plasmodium falciparum drug resistance].

    Science.gov (United States)

    Zhang, Mei-hua; Lu, Feng; Cao, Jun; Gao, Qi

    2015-06-01

    Effective chemotherapy is the mainstay of malaria control. However, it is undergoing the serious threat by resis- tance of falciparum malaria to antimalarial drugs. In recent years, with the development of molecular biology technology, molec- ular markers have been widely used to monitor antimalarial drug resistance. This paper reviews the researches on the common molecular markers related to Plasmodiumfalciparum drug resistance.

  9. Amplification of a Gene Related to Mammalian mdr Genes in Drug-Resistant Plasmodium falciparum

    Science.gov (United States)

    Wilson, Craig M.; Serrano, Adelfa E.; Wasley, Annemarie; Bogenschutz, Michael P.; Shankar, Anuraj H.; Wirth, Dyann F.

    1989-06-01

    The malaria parasite Plasmodium falciparum contains at least two genes related to the mammalian multiple drug resistance genes, and at least one of the P. falciparum genes is expressed at a higher level and is present in higher copy number in a strain that is resistant to multiple drugs than in a strain that is sensitive to the drugs.

  10. Drug Resistance versus Spiritual Resistance: A Comparative Analysis from the Perspective of Spiritual Health

    Directory of Open Access Journals (Sweden)

    Mohammad Baqer Mohammadi Laini

    2014-12-01

    Full Text Available Background and Objectives: Taking into account a few principles concerning human being, it becomes plausible that the human spirit would also have a similar reaction to spiritual “medicine” provided to it. In order to better understand how this is possible, we must consider the means by which the human spirit becomes resistant to spiritual remedies and compare them with the resistance developed by the body against physical drugs. As such, this research aimed at creating a comparative analysis between the elements that cause the human spirit to become resistant against spiritual remedies in comparison to the body’s resistance against physical treatments (e.g. drugs and other physical treatment. Methods: The research at hand highlights the conclusions of an overall study of the Holy Quran, books of Islamic narration, and extensive Internet research concerning this subject. With these resources, the various aspects of the spirit’s resistance against spiritual remedies were discussed in detail. Results: According to Holy Quran and Islamic narrations: Based on the expectations which God has of man, his heart (i.e. spirit has the potential to fall under one of two categories – positive or negative. An afflicted heart may at times, like an afflicted body, become resistant against a remedy designed to cure it. In both cases of physical or metaphysical resistance, the underlying element that causes this resistance as well as the symptoms which accompany it are similar to one another. Having considered the teachings found in religious texts, this research discovered the underlying causes of spiritual resistance, and outlined some solutions which can prevent this issue from arising in the first place. Conclusion: Based on the standards of health and spiritual wellbeing as outlined in Holy Quran, it is said that some hearts are unhealthy and require treatment and healing. In Holy Quran, there is also no doubt in it, guidance to the God wary

  11. Antifungal activity of essential oils of Origanum vulgare and Rosmarinus officinalis against three Candida albicans strains

    Directory of Open Access Journals (Sweden)

    Delić Dafina N.

    2013-01-01

    Full Text Available Due to general growing resistance and side effects to common antifungal drugs nowadays, there have been many studies reported on the use of herbal essential oils as antifungal agents in recent years. In this study, essential oils of Origanum vulgare and Rosmarinus officinalis (Lamiaceae were examined for their in vitro antifungal activity against three Candida albicans strains (laboratory - CAL, human pulmonary - CAH, and reference ATCC10231-CAR in comparison to Nystatin (0.30 mg/ml and Fluconazole (2 mg/ml as standard antifungal agents. The antifungal activity was evaluated by comparing inhibition zone diameters obtained both by disc-and well-diffusion assays, as well as by comparing MIC and MBC values detected by microdilution assay. Diffusion test results revealed stronger antifungal effect of O. vulgare against all analyzed C. albicans strains identifying CAL strain as the most susceptible one. Inhibition zones ranged from 12.65 to 25.10 mm depending on the concentrations applied. The highest concentrations of Rosemary essential oil (5.00 mg/ml demonstrated activity against two strains: CAL and CAR ATCC 10231 in both diffusion assays applied, while no antifungal activity was recorded against CAH isolate. Microdilution assay showed that both oils demonstrated the same MIC values for all tested strains (0.11 mg/ml, except MIC value against ATCC strain (0.23 mg/ml obtained for Rosemary essential oil. The obtained results indicated that oregano and rosemary essential oils might be highly effective in the natural prevention treatment of candidiasis, although toxicity assays should be previously preformed. [Projekat Ministarstva nauke Republike Srbije, br. 172058

  12. Managing drug-resistant epilepsy: challenges and solutions

    Science.gov (United States)

    Dalic, Linda; Cook, Mark J

    2016-01-01

    Despite the development of new antiepileptic drugs (AEDs), ~20%–30% of people with epilepsy remain refractory to treatment and are said to have drug-resistant epilepsy (DRE). This multifaceted condition comprises intractable seizures, neurobiochemical changes, cognitive decline, and psychosocial dysfunction. An ongoing challenge to both researchers and clinicians alike, DRE management is complicated by the heterogeneity among this patient group. The underlying mechanism of DRE is not completely understood. Many hypotheses exist, and relate to both the intrinsic characteristics of the particular epilepsy (associated syndrome/lesion, initial response to AED, and the number and type of seizures prior to diagnosis) and other pharmacological mechanisms of resistance. The four current hypotheses behind pharmacological resistance are the “transporter”, “target”, “network”, and “intrinsic severity” hypotheses, and these are reviewed in this paper. Of equal challenge is managing patients with DRE, and this requires a multidisciplinary approach, involving physicians, surgeons, psychiatrists, neuropsychologists, pharmacists, dietitians, and specialist nurses. Attention to comorbid psychiatric and other diseases is paramount, given the higher prevalence in this cohort and associated poorer health outcomes. Treatment options need to consider the economic burden to the patient and the likelihood of AED compliance and tolerability. Most importantly, higher mortality rates, due to comorbidities, suicide, and sudden death, emphasize the importance of seizure control in reducing this risk. Overall, resective surgery offers the best rates of seizure control. It is not an option for all patients, and there is often a significant delay in referring to epilepsy surgery centers. Optimization of AEDs, identification and treatment of comorbidities, patient education to promote adherence to treatment, and avoidance of triggers should be periodically performed until further

  13. Analysis of Antimicrobial Resistance Genes in Multiple Drug Resistant (MDR) Salmonella enterica Isolated from Animals and Humans

    Science.gov (United States)

    Background: Multiple Drug Resistant (MDR) foodborne bacteria are a concern in animal and human health. Identification of resistance genes in foodborne pathogens is necessary to determine similarities of resistance mechanisms in animal, food and human clinical isolates. This information will help us ...

  14. Second-line drug resistance in multidrug-resistant tuberculosis cases of various origins in the Netherlands.

    NARCIS (Netherlands)

    Ingen, J. van; Boeree, M.J.; Wright, A.; Laan, T.; Dekhuijzen, P.N.R.; Soolingen, D van

    2008-01-01

    SETTING: The Netherlands. OBJECTIVE: To investigate the frequency of resistance to second-line drugs among multidrug-resistant tuberculosis (MDR-TB) cases and its correlation with patients' geographic origin. DESIGN: Retrospective laboratory database study of multidrug-resistant Mycobacterium tuberc

  15. Susceptibilidad "in vitro" de cepas de Cryptococcus a 5 drogas antifungicas "In vitro" susceptibility of Cryptococcus strains to 5 antifungal drugs

    Directory of Open Access Journals (Sweden)

    A. J. Bava

    1989-10-01

    Full Text Available Se estudió la susceptibilidad "in vitro" de 24 cepas de 3 especies del género Cryptococcus a 5 drogas antifúngicas (anfotericina B, 5 fluorocitosina, ketoconazol, itraconazol y miconazol. Las mismas se agruparon según su especie, variedad y origen de aislamiento. Para determinar la concentración inhibitoria mínima (C.I.M. de cada droga se empleó el método de dilución en agar con el medio básico nitrogenado para levaduras, adicionado de glucosa. Se obtuvo además la media geométrica de estos valores para cada grupo y se comparó cada uno de ellos. Los resultados obtenidos fueron homogéneos con la sola excepción de las cepas de Cryptococcus sp (no neoformans, en las cuales se detectaron elevados valores de C.I.M. para la 5 fluorocitosina.A comparative study of the "in vitro" susceptibility of 24 Cryptococcus strains to 5 antifungal drugs (amphotericin B, 5 fluorocytosine, miconazole, itraconazole and ketoconazole, was carried out. These strains were grouped according to species, varieties and isolation's origins. The minimum inhibitory concentration (M.I.C. was determinated by the agar dilution technique in yeast nitrogen base agar with dextrose. The mean geometrical of the M.I.C. values of each group was compared with the others. The results obtained were homogeneous with the only exception of the "non neoformans" strains, in which, higher M.I.C. to 5 fluorocytosine values were detected.

  16. Global Introduction of New Multidrug-Resistant Tuberculosis Drugs-Balancing Regulation with Urgent Patient Needs.

    Science.gov (United States)

    Sullivan, Timothy; Ben Amor, Yanis

    2016-03-01

    New treatments for multidrug-resistant tuberculosis (MDR TB) are urgently needed. Two new drugs, bedaquiline and delamanid, have recently been released, and several new drugs and treatment regimens are in the pipeline. Misuse of TB drugs is a principal cause of drug resistance. As new drugs and regimens reach the market, the need to make them available to patients must be balanced with regulation of their use so that resistance to the new drugs can be prevented. To foster the rational use of new drugs, we propose 1) expanding/strengthening the capacity for drug susceptibility testing, beginning with countries with a high TB burden; 2) regulating prescribing practices by banning over-the-counter sale of TB drugs and enacting an accreditation system whereby providers must be certified to prescribe new drugs; and 3) decentralizing MDR TB care in rural communities by employing trained community health workers, using promising mobile technologies, and enlisting the aid of civil society organizations. PMID:26889711

  17. Prevalence and determinants of resistance to use drugs among adolescents who had an opportunity to use drugs *

    OpenAIRE

    Lopez-Quintero, Catalina; Neumark, Yehuda

    2015-01-01

    Background As drugs remain ubiquitous and their use increasingly viewed as socially normative, vulnerable population groups such as adolescents face continued and growing risk. A better understanding of the factors that discourage individuals from initiating drug use, particularly in enabling scenarios, is therefore needed. This study aims to identify individual, interpersonal and school-contextual factors associated with resistance to using drugs in the presence of a drug use opportunity amo...

  18. 2012-2014年南京地区34家医院抗真菌药物的使用情况分析%Analysis on utilization of antifungal drugs in 34 hospitals from Nanjing area during 2012 - 2014

    Institute of Scientific and Technical Information of China (English)

    储晓媚; 罗璨

    2016-01-01

    目的:了解南京地区34家医院2012—2014年抗真菌药物的使用情况和趋势,为临床合理用药提供参考。方法收集2012—2014年南京地区34家医院抗真菌药物的使用数据,对抗真菌药物的销售金额、用药频度(DDDs)等进行统计分析。结果2012—2014年南京地区34家医院抗真菌药物的总销售金额及构成比逐年上升。深部抗真菌药的用药金额远大于浅部抗真菌药,其中三唑类用药金额最大,其次是棘白菌素类。抗真菌药金额排序中三唑类药物排在前列,伏立康唑和氟康唑稳居第1、2位。浅表抗真菌药以特比萘芬为主,销售金额逐年下降。抗真菌药的DDDs排序中,深部抗真菌药中三唑类伊曲康唑排在前列,浅部抗真菌药克霉唑、硝呋太尔制霉素排名也居于前列。结论南京地区医院2012—2014年抗真菌药物的用药金额呈增长趋势,应加强对抗真菌药物的临床应用评价工作,从而促进抗真菌药的临床合理应用。%Objective To investigate the use and trend of antifungal drugs in 34 hospitals from Nanjing area during 2012 — 2014, and to provide reference for reasonable application of antifungal drugs.Methods The data of antifungal drugs in 34 hospitals from Nanjing area during 2012 — 2014 were collected, sales amount, consumption sum, and the frequency of drug use (DDDs) were analyzed statistically.Results The total consumption sum and constituent ratio of antifungal drugs in 34 hospitals from Nanjing area during 2012 — 2014 increased yearly. Consumption sum of deep antifungal drugs were more than those of superficial antifungal drugs. The consumption sum of triazoles was the largest, and the next were echinocandins. In the consumption sum sequence of antifungal drugs, voriconazole and fluconazole in triazoles ranked the first and second. Superficial antifungal drugs were mainly consisted of terbinafine, while the consumption sum of that

  19. 2012-2014年南京地区34家医院抗真菌药物的使用情况分析%Analysis on utilization of antifungal drugs in 34 hospitals from Nanjing area during 2012 - 2014

    Institute of Scientific and Technical Information of China (English)

    储晓媚; 罗璨

    2016-01-01

    Objective To investigate the use and trend of antifungal drugs in 34 hospitals from Nanjing area during 2012 — 2014, and to provide reference for reasonable application of antifungal drugs.Methods The data of antifungal drugs in 34 hospitals from Nanjing area during 2012 — 2014 were collected, sales amount, consumption sum, and the frequency of drug use (DDDs) were analyzed statistically.Results The total consumption sum and constituent ratio of antifungal drugs in 34 hospitals from Nanjing area during 2012 — 2014 increased yearly. Consumption sum of deep antifungal drugs were more than those of superficial antifungal drugs. The consumption sum of triazoles was the largest, and the next were echinocandins. In the consumption sum sequence of antifungal drugs, voriconazole and fluconazole in triazoles ranked the first and second. Superficial antifungal drugs were mainly consisted of terbinafine, while the consumption sum of that decreased yearly. In DDDs sequence of antifungal drugs, itraconazole in triazoles of antifungal drugs was ranked the first. In superficial antifungal drugs, clotrimazole and nifuratel nysfungin ranked the top. Conclusion The consumption sum of hospitals from Nanjing area has a tendency to increase. Therefore, clinical evaluation of antifungal drugs should be strengthened, and to promote reasonable application of antifungal drugs in clinic.%目的:了解南京地区34家医院2012—2014年抗真菌药物的使用情况和趋势,为临床合理用药提供参考。方法收集2012—2014年南京地区34家医院抗真菌药物的使用数据,对抗真菌药物的销售金额、用药频度(DDDs)等进行统计分析。结果2012—2014年南京地区34家医院抗真菌药物的总销售金额及构成比逐年上升。深部抗真菌药的用药金额远大于浅部抗真菌药,其中三唑类用药金额最大,其次是棘白菌素类。抗真菌药金额排序中三唑类药物排在前列,伏

  20. Antifungal susceptibility and virulence factors of clinically isolated dermatophytes in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Afshari

    2016-03-01

    Full Text Available Background and Objectives: Dermatophytes possess a wide array of virulence factors and various antifungal susceptibility patterns which influence their pathogenesis in humans and animals. The aim of this study was to evaluate antifungal suscep- tibility and keratinase and proteinase activity of 49 dermatophyte strains from the genera Microsporum, Trichophyton and Epidermophyton which were isolated from human cases of dermatophytosis.Materials and Methods: Forty-nine dermatophyte strains isolated from clinical samples were cultured on general and spe- cific culture media. Keratinase and proteinase activity was screened on solid mineral media and confirmed in liquid cultures. Drug susceptibility toward azoles (fluconazole, ketoconazole and itraconazole, griseofulvin and terbinafine was evaluated using disk diffusion method on Mueller-Hinton agar and minimum inhibitory concentrations (MICs were determined using microbroth dilution assay according to the Clinical and Laboratory Standards Institute (CLSI guidelines.Results: Our results indicated that clinically isolated dermatophytes from 7 major species produced keratinase and protein- ase at different extents. The mean keratinase and proteinase activity was reported as 6.69 ± 0.31 (U/ml and 2.10 ± 0.22 (U/ ml respectively. Disk diffusion and microbroth dilution (MIC results of antifungal susceptibility testing showed that ke- toconazole was the most effective drug against Epidermophyton floccosum and Trichophyton mentagrophytes, itraconazole against T. rubrum and E. floccosum, and griseofulvin and terbinafine against Trichophyton verrucosum. Our results showed that all dermatophyte isolates were resistant to fluconazole. Overall, ketoconazole and itraconazole were the most effective drugs for all dermatophyte species tested.Conclusion: Our results showed that antifungal susceptibility testing is an urgent need to select drugs of choice for treatment of different types of dermatophytosis and

  1. Antifungals of acromyrmex, allomerus, and tetraponera ant- and cultivarassociated bacteria

    OpenAIRE

    Barke, Joerg

    2013-01-01

    The central purpose of this thesis is to test the utility of ant-microbe associations for discovering antifungal compounds with novel molecular (sub-) structures. Novel antifungals displaying reduced adverse side-effects, increased water-solubilities, and/or strong fungicidal properties would be helpful in medical science for responding to the rising prevalence of human mycoses and for solving problems with adverse side-effects in currently used antifungal drugs. Host-symbiont systems m...

  2. Preformed antifungal compounds in strawberry fruit and flower tissues

    OpenAIRE

    Terry, Leon A.; Joyce, Daryl C.; Adikaram, Nimal K. B.; Khambay, Bhupinder P. S.

    2004-01-01

    Antifungal activity against the pathogen, Botrytis cinerea, and a bioassay organism, Cladosporium cladosporioides, declined with advancing strawberry fruit maturity as shown by thin layer chromatography (TLC) bioassays. Preformed antifungal activity was also present in flower tissue. The fall in fruit antifungal compounds was correlated with a decline in natural disease resistance (NDR) against B. cinerea in-planta. Crude extracts of green stage I fruit (7 days after anthesi...

  3. The problem of resistant Trichomonas vaginalis to antiprotozoal drugs

    Directory of Open Access Journals (Sweden)

    A. L. Poznyak

    2011-01-01

    Full Text Available This review presents recent data on the energy metabolism of Trichomonas vaginalis and ways the activation of metronidazole. The sensitivity of microorganisms to the 5-nitroimidazole by the presence of their enzyme systems, generating and transporting electrons, which can then transfer them to the nitro group of the drug. In T.vaginalis these are pyruvate ferredoxin-oxydoreductase, thioredoxin reductase and flavin reductase. The development of resistance T.vaginalis to metronidazole preparations of this multistep process, based on the gradual reduction (up to a loss activity hydrogenosomal enzymes and / or violation of the flavindependent metabolic pathways.

  4. Drug resistance in sea lice: a threat to salmonid aquaculture.

    Science.gov (United States)

    Aaen, Stian Mørch; Helgesen, Kari Olli; Bakke, Marit Jørgensen; Kaur, Kiranpreet; Horsberg, Tor Einar

    2015-02-01

    Sea lice are copepod ectoparasites with vast reproductive potential and affect a wide variety of fish species. The number of parasites causing morbidity is proportional to fish size. Natural low host density restricts massive parasite dispersal. However, expanded salmon farming has shifted the conditions in favor of the parasite. Salmon farms are often situated near wild salmonid migrating routes, with smolts being particularly vulnerable to sea lice infestation. In order to protect both farmed and wild salmonids passing or residing in the proximity of the farms, several measures are taken. Medicinal treatment of farmed fish has been the most predictable and efficacious, leading to extensive use of the available compounds. This has resulted in drug-resistant parasites occurring on farmed and possibly wild salmonids. PMID:25639521

  5. Pattern of primary tuberculosis drug resistance and associated treatment outcomes in Transnistria, Moldova.

    Science.gov (United States)

    Dolgusev, O; Obevzenco, N; Padalco, O; Pankrushev, S; Ramsay, A; Van den Bergh, R; Manzi, M; Denisiuk, O; Zachariah, R

    2014-10-21

    This cohort study assessed drug susceptibility testing (DST) patterns and associated treatment outcomes from Transnistria, Moldova, from 2009 to 2012. Of 1089 newly registered tuberculosis (TB) patients with available DST results, 556 (51%) had some form of drug resistance, while 369 (34%) had multidrug-resistant TB (MDR-TB). There were four cases of extensively drug-resistant TB. MDR-TB patients had poor treatment success (45%); human immunodeficiency virus positivity and a history of incarceration were associated with an unfavourable treatment outcome. This first study from Trans-nistria shows a high level of drug-resistant TB, which constitutes a major public health problem requiring urgent attention.

  6. Consensus drug resistance mutations for epidemiological surveillance: basic principles and potential controversies.

    Science.gov (United States)

    Shafer, Robert W; Rhee, Soo-Yon; Bennett, Diane E

    2008-01-01

    Programmes that monitor local, national and regional levels of transmitted HIV-1 drug resistance inform treatment guidelines and provide feedback on the success of HIV-1 treatment and prevention programmes. The World Health Organization (WHO) has established a global programme for genotypic surveillance of HIV-1 drug resistance and has recommended the adoption of a consensus definition of genotypic drug resistance. Such a definition is necessary to accurately compare transmitted drug resistance rates across geographical regions and time periods. HIV-1 diversity and the large number of mutations associated with antiretroviral drug resistance complicate the development of a consensus definition for genotypic drug resistance. This paper reviews the data that must be considered to determine which of the many HIV-1 drug resistance mutations are likely to be both sensitive and specific indicators of transmitted drug resistance. The process used to create a previously published list of drug resistance mutations for HIV-1 surveillance is reviewed and alternative approaches to this process are discussed. PMID:18575192

  7. 3-Halo Chloroquine Derivatives Overcome Plasmodium falciparum Chloroquine Resistance Transporter-Mediated Drug Resistance in P. falciparum.

    Science.gov (United States)

    Edaye, Sonia; Tazoo, Dagobert; Bohle, D Scott; Georges, Elias

    2015-12-01

    Polymorphism in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) was shown to cause chloroquine resistance. In this report, we examined the antimalarial potential of novel 3-halo chloroquine derivatives (3-chloro, 3-bromo, and 3-iodo) against chloroquine-susceptible and -resistant P. falciparum. All three derivatives inhibited the proliferation of P. falciparum; with 3-iodo chloroquine being most effective. Moreover, 3-iodo chloroquine was highly effective at potentiating and reversing chloroquine toxicity of drug-susceptible and -resistant P. falciparum.

  8. Harnessing evolutionary fitness in Plasmodium falciparum for drug discovery and suppressing resistance

    OpenAIRE

    Lukens, Amanda Kathleen; Ross, L. S.; Heidebrecht, Richard W; Javier Gamo, F.; Lafuente-Monasterio, M. J.; Booker, M. L.; Hartl, Daniel L.; Wiegand, R C; Wirth, Dyann F

    2013-01-01

    Drug resistance emerges in an ecological context where fitness costs restrict the diversity of escape pathways. These pathways are targets for drug discovery, and here we demonstrate that we can identify small-molecule inhibitors that differentially target resistant parasites. Combining wild-type and mutant-type inhibitors may prevent the emergence of competitively viable resistance. We tested this hypothesis with a clinically derived chloroquine-resistant (CQr) malaria parasite and with para...

  9. Application of antifungal drugs in the treatment of cutaneous and mucocutaneous leishmaniasis%抗真菌药物在皮肤黏膜利什曼病治疗中的应用

    Institute of Scientific and Technical Information of China (English)

    曲卉; 李若瑜; 余进; 王爱平

    2015-01-01

    Leishmaniasis is zoonotic disease caused byLeishmania with different clinical manifestations. It can be characterized into three clinical types: visceral leishmaniasis, mucocutaneous leishmaniasis and cutaneous leishmaniasis. Traditionally, antimony is the ifrst-line treatment for leishmaniasis, but its application is compromised due to the high adverse effects and the emergence of drug resistantLeishmania isolates. Clinical researches have shown that amphotericin B can be used in patients infected by antimony resistant isolates, and treatment of azole and propylene amine can also be effective and safe. Through the analysis of the components inLeishmania membrane, this article further illustrates the mechanism, usage and efifcacy of antifungal agents in the treatment of leishmaniasis.%利什曼病(leishmaniasis)是由利什曼原虫(Leishmania spp)引起的一组具有不同临床表现的疾病,可分为内脏利什曼病、黏膜皮肤利什曼病和皮肤利什曼病3个临床类型。利什曼病的治疗首选五价锑制剂,但因其不良反应发生率高、部分利什曼原虫对锑剂耐药,应用受到了一定的限制。临床研究显示抗真菌药物两性霉素B可以用于对锑剂耐药的患者,唑类和丙烯胺类抗真菌药物对部分利什曼病治疗有效、安全。该文从利什曼原虫胞膜成分的分析入手,重点介绍抗真菌药物在利什曼病治疗中的作用机制、用法及疗效。

  10. Autophagy and Transporter-Based Multi-Drug Resistance

    Directory of Open Access Journals (Sweden)

    Zhe-Sheng Chen

    2012-08-01

    Full Text Available All the therapeutic strategies for treating cancers aim at killing the cancer cells via apoptosis (programmed cell death type I. Defective apoptosis endow tumor cells with survival. The cell can respond to such defects with autophagy. Autophagy is a cellular process by which cytoplasmic material is either degraded to maintain homeostasis or recycled for energy and nutrients in starvation. A plethora of evidence has shown that the role of autophagy in tumors is complex. A lot of effort is needed to underline the functional status of autophagy in tumor progression and treatment, and elucidate how to tweak autophagy to treat cancer. Furthermore, during the treatment of cancer, the limitation for the cure rate and survival is the phenomenon of multi drug resistance (MDR. The development of MDR is an intricate process that could be regulated by drug transporters, enzymes, anti-apoptotic genes or DNA repair mechanisms. Reports have shown that autophagy has a dual role in MDR. Furthermore, it has been reported that activation of a death pathway may overcome MDR, thus pointing the importance of other death pathways to regulate tumor cell progression and growth. Therefore, in this review we will discuss the role of autophagy in MDR tumors and a possible link amongst these phenomena.

  11. Multi-drug resistant Acinetobacter ventilator-associated pneumonia

    Directory of Open Access Journals (Sweden)

    Shete Vishal

    2010-01-01

    Full Text Available Background: Ventilator-associated pneumonia (VAP due to a multi-drug resistant (MDR Acinetobacter is one of the most dreadful complications, which occurs in the critical care setting. Aims and objectives: To find out the incidence of Acinetobacter infection in VAP cases, to determine various risk factors responsible for acquisition of Acinetobacter infection and to determine the antimicrobial susceptibility pattern of Acinetobacter. Materials and Methods: A total of 60 endotracheal aspirate specimens from intubated patients diagnosed clinically and microscopically as VAP were studied bacteriologically. All clinical details and prior exposure to antibiotics were recorded. Results: An incidence of 11.6% of Acinetobacter VAP cases was recorded. Various underlying conditions like head injury, cerebral hemorrhage and chronic obstructive pulmonary disease (COPD were found to be associated with Acinetobacter VAP. Acinetobacter strains exhibited MDR pattern. Conclusion: Strict infection control measures, judicious prescribing of antibiotics, antibiotic resistance surveillance programs and antibiotic cycling should be adopted to control infections due to these bacteria in patients admitted to intensive care units.

  12. Detection of Low Frequency Multi-Drug Resistance and Novel Putative Maribavir Resistance in Immunocompromised Pediatric Patients with Cytomegalovirus

    Science.gov (United States)

    Houldcroft, Charlotte J.; Bryant, Josephine M.; Depledge, Daniel P.; Margetts, Ben K.; Simmonds, Jacob; Nicolaou, Stephanos; Tutill, Helena J.; Williams, Rachel; Worth, Austen J. J.; Marks, Stephen D.; Veys, Paul; Whittaker, Elizabeth; Breuer, Judith

    2016-01-01

    Human cytomegalovirus (HCMV) is a significant pathogen in immunocompromised individuals, with the potential to cause fatal pneumonitis and colitis, as well as increasing the risk of organ rejection in transplant patients. With the advent of new anti-HCMV drugs there is therefore considerable interest in using virus sequence data to monitor emerging resistance to antiviral drugs in HCMV viraemia and disease, including the identification of putative new mutations. We used target-enrichment to deep sequence HCMV DNA from 11 immunosuppressed pediatric patients receiving single or combination anti-HCMV treatment, serially sampled over 1–27 weeks. Changes in consensus sequence and resistance mutations were analyzed for three ORFs targeted by anti-HCMV drugs and the frequencies of drug resistance mutations monitored. Targeted-enriched sequencing of clinical material detected mutations occurring at frequencies of 2%. Seven patients showed no evidence of drug resistance mutations. Four patients developed drug resistance mutations a mean of 16 weeks after starting treatment. In two patients, multiple resistance mutations accumulated at frequencies of 20% or less, including putative maribavir and ganciclovir resistance mutations P522Q (UL54) and C480F (UL97). In one patient, resistance was detected 14 days earlier than by PCR. Phylogenetic analysis suggested recombination or superinfection in one patient. Deep sequencing of HCMV enriched from clinical samples excluded resistance in 7 of 11 subjects and identified resistance mutations earlier than conventional PCR-based resistance testing in 2 patients. Detection of multiple low level resistance mutations was associated with poor outcome. PMID:27667983

  13. 我院2009-2011年老年真菌感染菌种分布及其对抗真菌药敏感性分析%Analysis of Species Distribution and Drug Susceptibility to Antifungal Agents in the Aged with Fungal Infection of Our Hospital during 2009-2011

    Institute of Scientific and Technical Information of China (English)

    张慧儿; 裘莉佩

    2013-01-01

    目的:探讨临床老年患者标本中所分离的假丝酵母菌属的菌种分布及其对临床常用抗真菌药的敏感性,为老年人使用抗真菌药提供参考.方法:对我院2009-2011年从老年体内分离的213例假丝酵母菌进行回顾性分析,分析其菌种分布情况以及对5种抗真菌药的敏感性.结果:在213株假丝酵母菌中,白假丝酵母菌占42.3%(90/213),非白假丝酵母菌占57.7% (123/213);5-氟胞嘧啶、两性霉素B、氟康唑、伊曲康唑和伏立康唑的总敏感率分别为87.8%、100%、93.2%、85.9%和95.9%;90株白假丝酵母菌对上述5种抗真菌药的敏感率分别为93.3%、100%、95.4%、92.2%和96.3%,123株非白假丝酵母菌分别为83.7%、100%、91.6%、81.3%和95.6%.结论:在老年感染假丝酵母菌中最常见的菌种仍是白假丝酵母菌,但其比例较已报道的非老年感染者比例有所下降;白假丝酵母菌对常用抗真菌药仍有较高的敏感性,非白假丝酵母菌的耐药性则高于白假丝酵母菌.%OBJECTIVE: To discuss the species distribution and drug susceptibility to antifungal agent of isolated Candida, and to provide reference for the use of antifungal agent in the aged. METHODS: A total of 213 isolates were collected from our hospital during 2009 — 2011 were analyzed statistically, and the species distribution of Candida and drug resistance to 5 commonly used antifungal agents were analyzed. RESULTS: Among 213 Candida, Candida albicans accounted for 42.3% (90/213) and non-Candida albicans accounted for 57.7% (123/213). The overall percentage of strains susceptible to 5-flucytosine, amphotericin B, flucytosine, itraconazole and voriconazole were 87.8% , 100% , 93.2% , 85.9% and 95.9% , respectively. About 93.3% , 100%, 95.4% , 92.2% and 96.3% of 90 strains of Candida albicans were susceptible to these 5 antifungal agents. The susceptibility rates of 123 non-Candida albicans isolates were 83.7%, 100

  14. Pay close attention to prevalence and treatment of multi-drug-resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    Hong-bing CHEN

    2011-03-01

    Full Text Available Multi-drug-resistant tuberculosis(MDR-TB and extensive-drug-resistant tuberculosis(XDR-TB has become more prevalent worldwide.It is a disease which is difficult and expensive to treatment,with poor prognosis and high mortality.The spread of HIV accelerated the progression of malignancy of infection of tuberculosis.The evolution of MDR-and XDR-Mycobacterium tuberculosis had been a complicated and dynamic process related to the drug-resistant genes and phenotypes.The new diagnostic and therapeutic methods,research on vaccines,and the research and application of new drugs would be conducive to inhibit the prevalence of MDR-TB and XDR-TB.Prevention of initial drug-resistance infection should be emphasized in the prevention of drug-resistant TB.

  15. Epidemiology and patterns of drug resistance among tuberculosis patients in Northwestern Iran

    Directory of Open Access Journals (Sweden)

    L Sahebi

    2016-01-01

    Full Text Available Background: Multidrug-resistant tuberculosis (MDR-TB has emerged as an important global health concern and is on the rise throughout the world. Objective: The aim of this study was to examine the epidemiology and pattern of TB drug resistance. Methods: In this cross-sectional study, 180 pulmonary TB patients from two Northwestern provinces of Iran were selected. The first and second line drug susceptibility testing was carried out using the 1% proportion method on the Lφwenstein-Jensen medium. Full demographic, environmental and clinical history was evaluated. Results: Prevalence of resistance to any TB drug was 13.8%. Eight (4.4% patients had MDR-TB (2.4% in the province of East Azerbaijan and 9.3% in the province of Ardabil and one patient had extensively drug-resistant TB. Patient resistance to both isoniazid and streptomycin was the most prevalent at a rate of 8.3%. Patients showed the least resistance to ethambutol (2.8%. There was a significant relationship between the previous history of TB drug treatment and TB drug resistance. Migrants from rural to urban areas were in high-risk groups for the occurrence of TB drug resistance. Conclusion: In our study, prevalence of MDR was less than the global average. It is essential to monitor the patients with previous history of TB treatment and migrants by rapid and accurate techniques in terms of drug-resistance odds.

  16. Higher Desolvation Energy Reduces Molecular Recognition in Multi-Drug Resistant HIV-1 Protease

    Directory of Open Access Journals (Sweden)

    Ladislau C. Kovari

    2012-05-01

    Full Text Available Designing HIV-1 protease inhibitors that overcome drug-resistance is still a challenging task. In this study, four clinical isolates of multi-drug resistant HIV-1 proteases that exhibit resistance to all the US FDA-approved HIV-1 protease inhibitors and also reduce the substrate recognition ability were examined. A multi-drug resistant HIV-1 protease isolate, MDR 769, was co-crystallized with the p2/NC substrate and the mutated CA/p2 substrate, CA/p2 P1’F. Both substrates display different levels of molecular recognition by the wild-type and multi-drug resistant HIV-1 protease. From the crystal structures, only limited differences can be identified between the wild-type and multi-drug resistant protease. Therefore, a wild-type HIV-1 protease and four multi-drug resistant HIV-1 proteases in complex with the two peptides were modeled based on the crystal structures and examined during a 10 ns-molecular dynamics simulation. The simulation results reveal that the multi-drug resistant HIV-1 proteases require higher desolvation energy to form complexes with the peptides. This result suggests that the desolvation of the HIV-1 protease active site is an important step of protease-ligand complex formation as well as drug resistance. Therefore, desolvation energy could be considered as a parameter in the evaluation of future HIV-1 protease inhibitor candidates.

  17. Overcoming of multidrug resistance by introducing the apoptosis gene, bcl-Xs, into MRP-overexpressing drug resistant cells.

    Science.gov (United States)

    Ohi, Y; Kim, R; Toge, T

    2000-05-01

    Multidrug resistance associated protein (MRP) is one of drug transport membranes that confer multidrug resistance in cancer cells. Multidrug resistance has been known to be associated with resistance to apoptosis. In this study, using MRP overexpressing multidrug resistant nasopharyngeal cancer cells, we examined the expression of apoptosis related genes including p53, p21WAF1, bax and bcl-Xs between drug sensitive KB and its resistant KB/7D cells. We also examined whether the introduction of apoptosis related gene could increase the sensitivity to anticancer drugs in association with apoptotic cell death. The relative resistances to anticancer drugs in KB/7D cells evaluated by IC50 values were 3.6, 61.3, 10.4 and 10.5 to adriamycin (ADM), etoposide (VP-16), vincristine (VCR) and vindesine (VDS), respectively. The resistance to anticancer drugs in KB/7D cells was associated with the attenuation of internucleosomal DNA ladder formation in apoptosis. Of important, the mRNA expression of bcl-Xs gene in KB/7D cells was decreased in one-fourth as compared to that of KB cells among the apoptosis genes. The mRNA expression of bcl-Xs gene in a bcl-Xs transfected clone (KB/7Dbcl-Xs) was increased about 2-fold compared to that of KB/7Dneo cells, while the mRNA expression of MRP gene was not significantly different in KB/7bcl-Xs and KB/7Dneo cells. The sensitivities to anticancer drugs including ADM, VCR and VDS except VP-16 were increased in KB/7Dbcl-Xs cells, in turn, the relative resistance in KB/7Dbcl-Xs cells was decreased to 1.4, 4.0, and 3.0 in ADM, VCR and VDS, respectively, as compared to those of KB/7Dneo cells. Of interest, the studies on the accumulation of [3H]VCR showed that the decrease of [3H]VCR accumulation in KB/7Dbcl-Xs was not significantly different from that of KB/7Dneo cells. Collectively, these results indicated that the mechanism(s) of drug resistance in KB/7D cells could be explained at least by two factors: a) reduced drug accumulation mediated by

  18. Toward genetic transformation of mitochondria in mammalian cells using a recoded drug-resistant selection marker

    Institute of Scientific and Technical Information of China (English)

    Young Geol Yoon; Michael Duane Koob

    2011-01-01

    Due to technical difficulties, the genetic transformation of mitochondria in mammalian cells is still a challenge. In this report, we described our attempts to transform mammalian mitochondria with an engineered mitochondrial genome based on selection using a drug resistance gene. Because the standard drug-resistant neomycin phosphotransferase confers resistance to high concentrations of G418 when targeted to the mitochondria, we generated a recoded neomycin resistance gene that uses the mammalian mitochondrial genetic code to direct the synthesis of this protein in the mitochondria, but not in the nucleus (mitochondrial version). We also generated a universal version of the recoded neomycin resistance gene that allows synthesis of the drug-resistant proteins both in the mitochondria and nucleus. When we transfected these recoded neomycin resistance genes that were incorporated into the mouse mitochondrial genome clones into mouse tissue culture cells by electroporation, no DNA constructs were delivered into the mitochondria. We found that the universal version of the recoded neomycin resistance gene was expressed in the nucleus and thus conferred drug resistance to G418 selection, while the synthetic mitochondrial version of the gene produced no background drug-resistant cells from nuclear transformation. These recoded synthetic drug-resistant genes could be a useful tool for selecting mitochondrial genetic transformants as a precise technology for mitochondrial transformation is developed.

  19. Determination of antifungal susceptibility patterns among the environmental isolates of Aspergillus fumigatus in Iran

    Science.gov (United States)

    Mohammadi, Faezeh; Dehghan, Parvin; Nekoeian, Shahram; Hashemi, Seyed Jamal

    2016-01-01

    Background: In recent years, triazole-resistant environmental isolates of Aspergillus fumigatus have emerged in Europe and Asia. Azole resistance has been reported in patients who are treated with long-term azole therapy or exposure of the fungus spores to the azole fungicides used in agriculture. To date, a wide range of mutations in A. fumigatus have been described conferring azole-resistance, which commonly involves modifications in the cyp51A gene. We investigated antifungal susceptibility pattern of environmental isolates of A. fumigatus. Materials and Methods: In this study, 170 environmental samples collected from indoors surfaces of three hospitals in Iran. It was used β-tubulin gene to confirm the all of A. fumigatus isolates, which was identified by conventional methods. Furthermore, the antifungal susceptibility of itraconazole, voriconazole, and posaconazole was investigated using broth microdilution test, according to European Committee on Antimicrobial Susceptibility testing reference method. Results: From a total of 158 environmental molds fungi obtained from the hospitals, 58 isolates were identified as A. fumigatus by amplification of expected size of β-tubulin gene (~500 bp). In this study, in vitro antifungal susceptibility testing has shown that there were not high minimum inhibitory concentration values of triazole antifungals in all of the 58 environmental isolates of A. fumigatus. Conclusion: Our findings demonstrated that there was not azole-resistant among environmental isolates of A. fumigatus. Medical triazoles compounds have structural similarity with triazole fungicide compounds in agriculture, therefore, resistance development through exposure to triazole fungicide compounds in the environment is important but it sounds there is not a serious health problem in drug resistance in environmental isolates in Iran. PMID:27656605

  20. Collateral Resistance and Sensitivity Modulate Evolution of High-Level Resistance to Drug Combination Treatment in Staphylococcus aureus

    DEFF Research Database (Denmark)

    de Evgrafov, Mari Cristina Rodriguez; Gumpert, Heidi; Munck, Christian;

    2015-01-01

    As drug-resistant pathogens continue to emerge, combination therapy will increasingly be relied upon to treat infections and to help combat further development of multidrug resistance. At present a dichotomy exists between clinical practice, which favors therapeutically synergistic combinations......, and the scientific model emerging from in vitro experimental work, which maintains that this interaction provides greater selective pressure toward resistance development than other interaction types. We sought to extend the current paradigm, based on work below or near minimum inhibitory...... concentration levels, to reflect drug concentrations more likely to be encountered during treatment. We performed a series of adaptive evolution experiments using Staphylococcus aureus. Interestingly, no relationship between drug interaction type and resistance evolution was found as resistance increased...

  1. Rapid determination of antifungal activity by flow cytometry.

    OpenAIRE

    Green, L.; Petersen, B.; Steimel, L; Haeber, P; Current, W

    1994-01-01

    We have developed a rapid assay of antifungal activity which utilizes flow cytometry to detect accumulation of a vital dye in drug-damaged fungal cells. Results of these studies suggest that flow cytometry may provide an improved, rapid method for determining and comparing the antifungal activities of compounds with differing modes of action.

  2. Predicting drug resistance of the HIV-1 protease using molecular interaction energy components.

    Science.gov (United States)

    Hou, Tingjun; Zhang, Wei; Wang, Jian; Wang, Wei

    2009-03-01

    Drug resistance significantly impairs the efficacy of AIDS therapy. Therefore, precise prediction of resistant viral mutants is particularly useful for developing effective drugs and designing therapeutic regimen. In this study, we applied a structure-based computational approach to predict mutants of the HIV-1 protease resistant to the seven FDA approved drugs. We analyzed the energetic pattern of the protease-drug interaction by calculating the molecular interaction energy components (MIECs) between the drug and the protease residues. Support vector machines (SVMs) were trained on MIECs to classify protease mutants into resistant and nonresistant categories. The high prediction accuracies for the test sets of cross-validations suggested that the MIECs successfully characterized the interaction interface between drugs and the HIV-1 protease. We conducted a proof-of-concept study on a newly approved drug, darunavir (TMC114), on which no drug resistance data were available in the public domain. Compared with amprenavir, our analysis suggested that darunavir might be more potent to combat drug resistance. To quantitatively estimate binding affinities of drugs and study the contributions of protease residues to causing resistance, linear regression models were trained on MIECs using partial least squares (PLS). The MIEC-PLS models also achieved satisfactory prediction accuracy. Analysis of the fitting coefficients of MIECs in the regression model revealed the important resistance mutations and shed light into understanding the mechanisms of these mutations to cause resistance. Our study demonstrated the advantages of characterizing the protease-drug interaction using MIECs. We believe that MIEC-SVM and MIEC-PLS can help design new agents or combination of therapeutic regimens to counter HIV-1 protease resistant strains. PMID:18704937

  3. Advancements in Topical Antifungal Vehicles.

    Science.gov (United States)

    Kircik, Leon H

    2016-02-01

    The primary treatment for superficial fungal infections is antifungal topical formulations, and allylamines and azoles represent the two major classes of topical formulations that are used to treat these infections. The stratum corneum (SC) is composed of keratinocytes that are surrounded by a matrix of lipids. The efficacy of topically applied formulations depends on their ability to penetrate this lipid matrix, and the vehicle plays an integral role in the penetration of active molecule into skin. There are several challenges to formulating topical drugs, which include the biotransformation of the active molecules as they pass through the SC and the physical changes that occur to the vehicle itself when it is applied to the skin. This article will review current and emerging topical antifungal vehicles. PMID:26885798

  4. Efficacy of verapamil as an adjunctive treatment in children with drug-resistant epilepsy

    DEFF Research Database (Denmark)

    Nicita, Francesco; Spalice, Alberto; Papetti, Laura;

    2014-01-01

    Verapamil, a voltage-gated calcium channel blocker, has been occasionally reported to have some effect on reducing seizure frequency in drug-resistant epilepsy or status epilepticus. We aimed to investigate the efficacy of verapamil as add-on treatment in children with drug-resistant epilepsy....

  5. Transferable and non-transferable drug resistance in enteric bacteria from hospital and from general practice

    DEFF Research Database (Denmark)

    Møller, JK; Bak, AL; Bülow, P;

    1976-01-01

    Drug resistance to 8 different antibiotics in Enterobacteriaceae isolated from different hospitals and two groups of general practitioners was studied. Escherichia coli dominated among the 632 strains investigated. Drug resistance was found in 62% of the 512 hospital strains and in 38% of the 120...... alone or in combinations were the most common traits transferred....

  6. An Invitation to Project DARE: Drug Abuse Resistance Education. Program Brief.

    Science.gov (United States)

    Marx, Eva; DeJong, William

    Project DARE (Drug Abuse Resistance Education) is a substance use prevention education program designed to equip elementary school children with skills for resisting peer pressure to experiment with tobacco, drugs, and alcohol. This unique program, which was developed in 1983 as a cooperative effort by the Los Angeles Police Department and the Los…

  7. Extremely Drug-Resistant Salmonella enterica Serovar Senftenberg Infections in Patients in Zambia

    DEFF Research Database (Denmark)

    Hendriksen, Rene S.; Joensen, Katrine Grimstrup; Lukwesa-Musyani, Chileshe;

    2013-01-01

    Two cases of extremely drug-resistant Salmonella enterica serovar Senftenberg isolated from patients in Zambia were investigated by utilizing MIC determinations and whole-genome sequencing. The isolates were resistant to, and harbored genes toward, nine drug classes, including fluoroquinolones...

  8. Prevalence and Risk Factors of Primary Drug-Resistant Tuberculosis in China

    Institute of Scientific and Technical Information of China (English)

    WANG Sheng Fen; ZHOU Yang; PANG Yu; ZHENG Hui Wen; ZHAO Yan Lin

    2016-01-01

    ObjectiveTo investigatetheprevalence of primary drug-resistant tuberculosis (TB) and associated risk factors in China.We also explored factors contributing tothe transmission of multidrug-resistant tuberculosis (MDR-TB). MethodsA total of 2794 representative,Mycobacterium tuberculosis isolates from treatment-naive patients were subjected to drug susceptibility testing, and risk factors for drug-resistant TBwere analyzed. We also analyzed MDR-TB strain sublineages, drug-resistance-conferring mutations, and risk factors associated with clustered primary MDR strains. ResultsAmong 2794Mycobacterium tuberculosis isolates from treatment-naive patients, the prevalence of any resistance to first-line drugs was 33.2%andthe prevalence of MDR-TB was 5.7%. We did not find any risk factors significantly associated with resistance to first-line drugs.The93 primary MDR-TB isolates were classified into six sublineages, of which, 75 (80.6%) isolates were the RD105-deleted Beijing lineage.The largest sublineage included 65 (69.9%) isolates with concurrent deletions of RD105, RD207, and RD181.Twenty-nine (31.2%) primary MDR strains grouped in clusters;MDR isolates in clusters were more likely to have S531LrpoBmutation. ConclusionThis study indicates that primary drug-resistantTBand MDR-TBstrains are prevalent in China,and multiplemeasures should be taken toaddress drug-resistant TB.

  9. Transmission Intensity and Drug Resistance in Malaria Population Dynamics : Implications for Climate Change

    NARCIS (Netherlands)

    Artzy-Randrup, Yael; Alonso, David; Pascual, Mercedes

    2010-01-01

    Although the spread of drug resistance and the influence of climate change on malaria are most often considered separately, these factors have the potential to interact through altered levels of transmission intensity. The influence of transmission intensity on the evolution of drug resistance has b

  10. HIV-1 drug resistance among antiretroviral treatment-naïve Ethiopian patients

    Directory of Open Access Journals (Sweden)

    A Mulu

    2012-11-01

    Full Text Available Background: In many African countries, access to antiretroviral treatment (ART has been significantly scaled up over the last five years. Nevertheless, data on drug resistance mutation are scarce. The objective of the current study was to determine the predominant subtypes of HIV-1 as well as to identify baseline mutations with potential drug resistance among ART-naïve patients from Ethiopia. Methods: Genotypic drug resistance on the entire protease and partial reverse transcriptase (codons 1–335 regions of the pol gene was determined by an in-house protocol in 160 ART-naïve patients. Genotypic drug resistance was defined as the presence of one or more resistance-related mutations, as specified by the consensus of the Stanford University HIV drug resistance database (HIVDB available at http://hivdb.stanford.edu/ and the 2011 International AIDS Society (IAS mutation list (http://www.iasusa.org/resistance-mutations/. Results: A predominance of HIV-1 subtype C (98.7% was observed. According to the IAS mutation list, antiretroviral drug resistance mutations were detected in 20 patients (13%. However, the level of drug resistance is 5.2% (8/155 when the most conservative method, HIVDB algorithms were applied. In both algorithms, none had major PI mutation and mutation-conferring resistance to NRTI and NNRTI were not overlapping. Conclusions: There is strong evidence for clade homogeneity in Ethiopia and low influx of other subtypes to the country. The level of transmitted drug resistance exceeds that of WHO estimates and indicates that many HIV-infected individuals on ART are practicing risk-related behaviours. The results also show that HIV drug resistance testing should be installed in resource limited settings.

  11. The Association between Mycobacterium Tuberculosis Genotype and Drug Resistance in Peru.

    Directory of Open Access Journals (Sweden)

    Louis Grandjean

    Full Text Available The comparison of Mycobacterium tuberculosis bacterial genotypes with phenotypic, demographic, geospatial and clinical data improves our understanding of how strain lineage influences the development of drug-resistance and the spread of tuberculosis.To investigate the association of Mycobacterium tuberculosis bacterial genotype with drug-resistance. Drug susceptibility testing together with genotyping using both 15-loci MIRU-typing and spoligotyping, was performed on 2,139 culture positive isolates, each from a different patient in Lima, Peru. Demographic, geospatial and socio-economic data were collected using questionnaires, global positioning equipment and the latest national census.The Latin American Mediterranean (LAM clade (OR 2.4, p<0.001 was significantly associated with drug-resistance and alone accounted for more than half of all drug resistance in the region. Previously treated patients, prisoners and genetically clustered cases were also significantly associated with drug-resistance (OR's 2.5, 2.4 and 1.8, p<0.001, p<0.05, p<0.001 respectively.Tuberculosis disease caused by the LAM clade was more likely to be drug resistant independent of important clinical, genetic and socio-economic confounding factors. Explanations for this include; the preferential co-evolution of LAM strains in a Latin American population, a LAM strain bacterial genetic background that favors drug-resistance or the "founder effect" from pre-existing LAM strains disproportionately exposed to drugs.

  12. Epigenetic mechanisms of cell adhesion-mediated drug resistance in multiple myeloma.

    Science.gov (United States)

    Furukawa, Yusuke; Kikuchi, Jiro

    2016-09-01

    Multiple myeloma cells acquire the resistance to anti-cancer drugs through physical and functional interactions with the bone marrow microenvironment via two overlapping mechanisms. First, bone marrow stromal cells (BMSCs) produce soluble factors, such as interleukin-6 and insulin-like growth factor-1, to activate signal transduction pathways leading to drug resistance (soluble factor-mediated drug resistance). Second, BMSCs up-regulate the expression of cell cycle inhibitors, anti-apoptotic members of the Bcl-2 family and ABC drug transporters in myeloma cells upon direct adhesion [cell adhesion-mediated drug resistance (CAM-DR)]. Elucidation of the mechanisms underlying drug resistance may greatly contribute to the advancement of cancer therapies. Recent investigations, including ours, have revealed the involvement of epigenetic alterations in drug resistance especially CAM-DR. For example, we found that class I histone deacetylases (HDACs) determine the sensitivity of proteasome inhibitors and the histone methyltransferase EZH2 regulates the transcription of anti-apoptotic genes during the acquisition of CAM-DR by myeloma cells. In addition, another histone methyltransferase MMSET was shown to confer drug resistance to myeloma cells by facilitating DNA repair. These findings provide a rationale for the inclusion of epigenetic drugs, such as HDAC inhibitors and histone methylation modifiers, in combination chemotherapy for MM patients to increase the therapeutic index. PMID:27411688

  13. Hospital costs of nosocomial multi-drug resistant Pseudomonas aeruginosa acquisition

    Directory of Open Access Journals (Sweden)

    Morales Eva

    2012-05-01

    Full Text Available Abstract Background We aimed to assess the hospital economic costs of nosocomial multi-drug resistant Pseudomonas aeruginosa acquisition. Methods A retrospective study of all hospital admissions between January 1, 2005, and December 31, 2006 was carried out in a 420-bed, urban, tertiary-care teaching hospital in Barcelona (Spain. All patients with a first positive clinical culture for P. aeruginosa more than 48 h after admission were included. Patient and hospitalization characteristics were collected from hospital and microbiology laboratory computerized records. According to antibiotic susceptibility, isolates were classified as non-resistant, resistant and multi-drug resistant. Cost estimation was based on a full-costing cost accounting system and on the criteria of clinical Activity-Based Costing methods. Multivariate analyses were performed using generalized linear models of log-transformed costs. Results Cost estimations were available for 402 nosocomial incident P. aeruginosa positive cultures. Their distribution by antibiotic susceptibility pattern was 37.1% non-resistant, 29.6% resistant and 33.3% multi-drug resistant. The total mean economic cost per admission of patients with multi-drug resistant P. aeruginosa strains was higher than that for non-resistant strains (15,265 vs. 4,933 Euros. In multivariate analysis, resistant and multi-drug resistant strains were independently predictive of an increased hospital total cost in compared with non-resistant strains (the incremental increase in total hospital cost was more than 1.37-fold and 1.77-fold that for non-resistant strains, respectively. Conclusions P. aeruginosa multi-drug resistance independently predicted higher hospital costs with a more than 70% increase per admission compared with non-resistant strains. Prevention of the nosocomial emergence and spread of antimicrobial resistant microorganisms is essential to limit the strong economic impact.

  14. Hospital costs of nosocomial multi-drug resistant Pseudomonas aeruginosa acquisition

    Science.gov (United States)

    2012-01-01

    Background We aimed to assess the hospital economic costs of nosocomial multi-drug resistant Pseudomonas aeruginosa acquisition. Methods A retrospective study of all hospital admissions between January 1, 2005, and December 31, 2006 was carried out in a 420-bed, urban, tertiary-care teaching hospital in Barcelona (Spain). All patients with a first positive clinical culture for P. aeruginosa more than 48 h after admission were included. Patient and hospitalization characteristics were collected from hospital and microbiology laboratory computerized records. According to antibiotic susceptibility, isolates were classified as non-resistant, resistant and multi-drug resistant. Cost estimation was based on a full-costing cost accounting system and on the criteria of clinical Activity-Based Costing methods. Multivariate analyses were performed using generalized linear models of log-transformed costs. Results Cost estimations were available for 402 nosocomial incident P. aeruginosa positive cultures. Their distribution by antibiotic susceptibility pattern was 37.1% non-resistant, 29.6% resistant and 33.3% multi-drug resistant. The total mean economic cost per admission of patients with multi-drug resistant P. aeruginosa strains was higher than that for non-resistant strains (15,265 vs. 4,933 Euros). In multivariate analysis, resistant and multi-drug resistant strains were independently predictive of an increased hospital total cost in compared with non-resistant strains (the incremental increase in total hospital cost was more than 1.37-fold and 1.77-fold that for non-resistant strains, respectively). Conclusions P. aeruginosa multi-drug resistance independently predicted higher hospital costs with a more than 70% increase per admission compared with non-resistant strains. Prevention of the nosocomial emergence and spread of antimicrobial resistant microorganisms is essential to limit the strong economic impact. PMID:22621745

  15. Extraction and identification of exosomes from drug-resistant breast cancer cells and their potential role in cell-to-cell drug-resistance transfer

    Institute of Scientific and Technical Information of China (English)

    许金金

    2014-01-01

    Objective To explore whether docetaxel-resistant cells(MCF-7/Doc)and doxorubicin-resistant cells(MCF-7/ADM)can secrete Exosomes and their potential role in cell-cell drug-resistance transfer.Methods Exosomes were extracted from the cell culture supernatants of MCF-7/Doc and MCF-7/ADM cells by fractionation ultracentrifugation,and were identified by transmission

  16. Antifungal polypeptides

    Energy Technology Data Exchange (ETDEWEB)

    Altier, Daniel J. (Granger, IA); Dahlbacka, Glen (Oakland, CA); Ellanskaya, Irina (Kyiv, UA); Ellanskaya, legal representative, Natalia (Kyiv, UA); Herrmann, Rafael (Wilmington, DE); Hunter-Cevera, Jennie (Elliott City, MD); McCutchen, Billy F. (College Station, TX); Presnail, James K. (Avondale, PA); Rice, Janet A. (Wilmington, DE); Schepers, Eric (Port Deposit, MD); Simmons, Carl R. (Des Moines, IA); Torok, Tamas (Richmond, CA); Yalpani, Nasser (Johnston, IA)

    2012-04-03

    Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include novel amino acid sequences, and variants and fragments thereof, for antipathogenic polypeptides that were isolated from microbial fermentation broths. Nucleic acid molecules comprising nucleotide sequences that encode the antipathogenic polypeptides of the invention are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention, or variant or fragment thereof, are also disclosed.

  17. Drug-resistant tuberculosis control in China: progress and challenges

    Institute of Scientific and Technical Information of China (English)

    Qian Long; Yan Qu; Henry Lucas

    2016-01-01

    Background:China has the second highest caseload of multidrug-resistant tuberculosis (MDR-TB) in the world.In 2009,the Chinese government agreed to draw up a plan for MDR-TB prevention and control in the context of a comprehensive health system reform launched in the same year.Discussion:China is facing high prevalence rates of drug-resistant TB and MDR-TB.MDR-TB disproportionally affects the poor rural population and the highest rates are in less developed regions largely due to interrupted and/or inappropriate TB treatment.Most households with an affected member suffer a heavy financial burden because of a combination of treatment and other related costs.The influential Global Fund programme for MDR-TB control in China provides technical and financial support for MDR-TB diagnosis and treatment.However,this programme has a fixed timeline and cannot provide a long term solution.In 2009,the Bill and Melinda Gates Foundation,in cooperation with the National Health and Family Planning Commission of China,started to develop innovative approaches to TB/MDR-TB management and case-based payment mechanisms for treatment,alongside increased health insurance benefits for patients,in order to contain medical costs and reduce financial barriers to treatment.Although these efforts appear to be in the right direction,they may not be sufficient unless (a) domestic sources are mobilized to raise funding for TB/MDR-TB prevention and control and (b) appropriate incentives are given to both health facilities and their care providers.Summary:Along with the on-going Chinese health system reform,sustained government financing and social health protection schemes will be critical to ensure universal access to appropriate TB treatment in order to reduce risk of developing MDR-TB and systematic MDR-TB treatment and management.

  18. Fitness trade-offs in the evolution of dihydrofolate reductase and drug resistance in Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Marna S Costanzo

    Full Text Available BACKGROUND: Patterns of emerging drug resistance reflect the underlying adaptive landscapes for specific drugs. In Plasmodium falciparum, the parasite that causes the most serious form of malaria, antifolate drugs inhibit the function of essential enzymes in the folate pathway. However, a handful of mutations in the gene coding for one such enzyme, dihydrofolate reductase, confer drug resistance. Understanding how evolution proceeds from drug susceptibility to drug resistance is critical if new antifolate treatments are to have sustained usefulness. METHODOLOGY/PRINCIPAL FINDINGS: We use a transgenic yeast expression system to build on previous studies that described the adaptive landscape for the antifolate drug pyrimethamine, and we describe the most likely evolutionary trajectories for the evolution of drug resistance to the antifolate chlorcycloguanil. We find that the adaptive landscape for chlorcycloguanil is multi-peaked, not all highly resistant alleles are equally accessible by evolution, and there are both commonalities and differences in adaptive landscapes for chlorcycloguanil and pyrimethamine. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that cross-resistance between drugs targeting the same enzyme reflect the fitness landscapes associated with each particular drug and the position of the genotype on both landscapes. The possible public health implications of these findings are discussed.

  19. Identification of a New Class of Antifungals Targeting the Synthesis of Fungal Sphingolipids

    Science.gov (United States)

    Mor, Visesato; Rella, Antonella; Farnoud, Amir M.; Singh, Ashutosh; Munshi, Mansa; Bryan, Arielle; Naseem, Shamoon; Konopka, James B.; Ojima, Iwao; Bullesbach, Erika; Ashbaugh, Alan; Linke, Michael J.; Cushion, Melanie; Collins, Margaret; Ananthula, Hari Krishna; Sallans, Larry; Desai, Pankaj B.; Wiederhold, Nathan P.; Fothergill, Annette W.; Kirkpatrick, William R.; Patterson, Thomas; Wong, Lai Hong; Sinha, Sunita; Giaever, Guri; Nislow, Corey; Flaherty, Patrick; Pan, Xuewen; Cesar, Gabriele Vargas; de Melo Tavares, Patricia; Frases, Susana; Miranda, Kildare; Rodrigues, Marcio L.; Luberto, Chiara; Nimrichter, Leonardo

    2015-01-01

    ABSTRACT Recent estimates suggest that >300 million people are afflicted by serious fungal infections worldwide. Current antifungal drugs are static and toxic and/or have a narrow spectrum of activity. Thus, there is an urgent need for the development of new antifungal drugs. The fungal sphingolipid glucosylceramide (GlcCer) is critical in promoting virulence of a variety of human-pathogenic fungi. In this study, we screened a synthetic drug library for compounds that target the synthesis of fungal, but not mammalian, GlcCer and found two compounds [N′-(3-bromo-4-hydroxybenzylidene)-2-methylbenzohydrazide (BHBM) and its derivative, 3-bromo-N′-(3-bromo-4-hydroxybenzylidene) benzohydrazide (D0)] that were highly effective in vitro and in vivo against several pathogenic fungi. BHBM and D0 were well tolerated in animals and are highly synergistic or additive to current antifungals. BHBM and D0 significantly affected fungal cell morphology and resulted in the accumulation of intracellular vesicles. Deep-sequencing analysis of drug-resistant mutants revealed that four protein products, encoded by genes APL5, COS111, MKK1, and STE2, which are involved in vesicular transport and cell cycle progression, are targeted by BHBM. PMID:26106079

  20. Antifungal activity of redox-active benzaldehydes that target cellular antioxidation

    Directory of Open Access Journals (Sweden)

    Mahoney Noreen

    2011-05-01

    Full Text Available Abstract Background Disruption of cellular antioxidation systems should be an effective method for control of fungal pathogens. Such disruption can be achieved with redox-active compounds. Natural phenolic compounds can serve as potent redox cyclers that inhibit microbial growth through destabilization of cellular redox homeostasis and/or antioxidation systems. The aim of this study was to identify benzaldehydes that disrupt the fungal antioxidation system. These compounds could then function as chemosensitizing agents in concert with conventional drugs or fungicides to improve antifungal efficacy. Methods Benzaldehydes were tested as natural antifungal agents against strains of Aspergillus fumigatus, A. flavus, A. terreus and Penicillium expansum, fungi that are causative agents of human invasive aspergillosis and/or are mycotoxigenic. The yeast Saccharomyces cerevisiae was also used as a model system for identifying gene targets of benzaldehydes. The efficacy of screened compounds as effective chemosensitizers or as antifungal agents in formulations was tested with methods outlined by the Clinical Laboratory Standards Institute (CLSI. Results Several benzaldehydes are identified having potent antifungal activity. Structure-activity analysis reveals that antifungal activity increases by the presence of an ortho-hydroxyl group in the aromatic ring. Use of deletion mutants in the oxidative stress-response pathway of S. cerevisiae (sod1Δ, sod2Δ, glr1Δ and two mitogen-activated protein kinase (MAPK mutants of A. fumigatus (sakAΔ, mpkCΔ, indicates antifungal activity of the benzaldehydes is through disruption of cellular antioxidation. Certain benzaldehydes, in combination with phenylpyrroles, overcome tolerance of A. fumigatus MAPK mutants to this agent and/or increase sensitivity of fungal pathogens to mitochondrial respiration inhibitory agents. Synergistic chemosensitization greatly lowers minimum inhibitory (MIC or fungicidal (MFC

  1. Toward repurposing ciclopirox as an antibiotic against drug-resistant Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae.

    Directory of Open Access Journals (Sweden)

    Kimberly M Carlson-Banning

    Full Text Available Antibiotic-resistant infections caused by gram-negative bacteria are a major healthcare concern. Repurposing drugs circumvents the time and money limitations associated with developing new antimicrobial agents needed to combat these antibiotic-resistant infections. Here we identified the off-patent antifungal agent, ciclopirox, as a candidate to repurpose for antibiotic use. To test the efficacy of ciclopirox against antibiotic-resistant pathogens, we used a curated collection of Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae clinical isolates that are representative of known antibiotic resistance phenotypes. We found that ciclopirox, at 5-15 µg/ml concentrations, inhibited bacterial growth regardless of the antibiotic resistance status. At these same concentrations, ciclopirox reduced growth of Pseudomonas aeruginosa clinical isolates, but some of these pathogens required higher ciclopirox concentrations to completely block growth. To determine how ciclopirox inhibits bacterial growth, we performed an overexpression screen in E. coli. This screen revealed that galE, which encodes UDP-glucose 4-epimerase, rescued bacterial growth at otherwise restrictive ciclopirox concentrations. We found that ciclopirox does not inhibit epimerization of UDP-galactose by purified E. coli GalE; however, ΔgalU, ΔgalE, ΔrfaI, or ΔrfaB mutant strains all have lower ciclopirox minimum inhibitory concentrations than the parent strain. The galU, galE, rfaI, and rfaB genes all encode enzymes that use UDP-galactose or UDP-glucose for galactose metabolism and lipopolysaccharide (LPS biosynthesis. Indeed, we found that ciclopirox altered LPS composition of an E. coli clinical isolate. Taken together, our data demonstrate that ciclopirox affects galactose metabolism and LPS biosynthesis, two pathways important for bacterial growth and virulence. The lack of any reported fungal resistance to ciclopirox in over twenty years of use in the clinic

  2. Phylogeny and drug resistance of HIV PR gene among HIV patients receiving RT inhibitors in Iran

    Institute of Scientific and Technical Information of China (English)

    Kazem Baesi; Majedeh Moradbeigi; Mehrdad Ravanshad; Ashrafolnesa Baghban

    2016-01-01

    Objective: To survey the level and patterns of reverse transcriptase-based drug resistance and subtype distribution among antiretroviral-treated HIV-infected patients receiving only reverse transcriptase inhibitors in Iran. Methods: A total of 25 samples of antiretroviral therapy experienced patients with no history of using protease inhibitors were collected. After RNA extraction, reverse transcriptase-nested PCR was performed. The final products were sequenced and then analysed for drug-resistant mutations and subtypes. Results: No drug resistant mutations were observed among the 25 subjects. The results showed the following subtypes among patients:CRF 35_AD (88%), CRF 28_BF (8%), and CRF 29_BF (4%). Conclusions: A significant increase in drug resistance has been noted in recently-infected patients worldwide. Subtype distributions are needed to perform properly-designed surveillance studies to continuously monitor rates and patterns of transmitted drug resistance and subtypes to help guide therapeutic approaches and limit transmission of these variants.

  3. Prevalence of drug-resistant tuberculosis in mainland China: systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Yu Yang

    Full Text Available BACKGROUND: The spread of drug-resistant tuberculosis (TB is one of the major public health problems in the world. Surveillance of anti-TB drug resistance is important for monitoring TB control strategies. However, the status of drug-resistant TB in China has been reported inconsistently. METHODS: We systematically reviewed published studies on drug-resistant TB in China until March 31, 2011, and quantitatively summarized prevalence and patterns of anti-TB drug resistance among new cases and previously treated cases, respectively. RESULTS: Ninety-five eligible articles, published during 1993-2011, were included in this review. The meta-analyses showed that the prevalence of drug-resistant TB in new cases was 27.9% (95% CI, 25.6%-30.2% (n/N = 27,360/104,356 and in previously treated cases was 60.3% (95% CI, 56.2%-64.2% (n/N = 30,350/45,858. Furthermore, in these two study populations, the prevalence of multiple drug resistance was found to be 5.3% (95% CI, 4.4%-6.4% (n/N = 8810/101,718 and 27.4% (95% CI, 24.1%-30.9% (n/N = 10,486/44,530 respectively. However, the results were found to be frequently heterogeneous (p for Q tests <0.001. The most common resistance was observed for isoniazid among both study populations. Different patterns of drug resistance were observed in the subgroup analysis with respect to geographic areas, drug susceptibility testing methods and subject enrollment time. CONCLUSIONS: Results of meta-analyses indicated a severe status of drug-resistant TB in China, which attaches an importance to strength TB prevention and control.

  4. Prevalence and risk factors associated with drug resistant TB in South West, Nigeria

    Institute of Scientific and Technical Information of China (English)

    Olusoji Daniel; Eltayeb Osman

    2011-01-01

    Objective:To determine the prevalence and risk factors associated with drug resistant tuberculosis(TB) in South West Nigeria.Methods: A retrospective study conducted among pulmonary tuberculosis (PTB) patients from Oyo and Osun States in South West Nigeria who had their culture and drug susceptibility test performed at the institute of tropical medicine Antwerp, Belgium between2007 and2009. Data on the patient’s characteristics were retrieved from the TB treatment card. Univariate analysis was performed to assess the risk factors for drug resistant tuberculosis. The Level of significance was atP<0.05.Results:Among the88 patients who had drug-susceptibility test result, there were50 males and38 females. Of the88patients,55 (62.5%) had strains resistant to at least one or more anti-drugs. The proportion ofTBcases with resistance to a single drug was12.7%. The multi-drug resistantTB (MDR-TB) rate was76.4%. The only significant factor for the development of drug resistance andMDR was the history of previous anti TB treatment (P<0.01). Other factors such as age[OR 0.86 (0.35-2.13);P=0.72] and gender[OR 1.24 (0.49-3.14);P=0.62] were not significantly associated with drug resistanceTB.Conclusions: The study highlighted a high prevalence ofMDR-TBamong the study population. History of previous TB treatment was associated withMDR-TB. There is an urgent need to conduct a nationalTB drug resistance survey to determine the actual burden and risk factors associated with drug resistance TB in the country.

  5. Clinical and operational value of the extensively drug-resistant tuberculosis definition.

    Science.gov (United States)

    Migliori, G B; Besozzi, G; Girardi, E; Kliiman, K; Lange, C; Toungoussova, O S; Ferrara, G; Cirillo, D M; Gori, A; Matteelli, A; Spanevello, A; Codecasa, L R; Raviglione, M C

    2007-10-01

    Currently, no information is available on the effect of resistance/susceptibility to first-line drugs different from isoniazid and rifampicin in determining the outcome of extensively drug-resistant tuberculosis (XDR-TB) patients, and whether being XDR-TB is a more accurate indicator of poor clinical outcome than being resistant to all first-line anti-tuberculosis (TB) drugs. To investigate this issue, a large series of multidrug-resistant TB (MDR-TB) and XDR-TB cases diagnosed in Estonia, Germany, Italy and the Russian Federation during the period 1999-2006 were analysed. Drug-susceptibility testing for first- and second-line anti-TB drugs, quality assurance and treatment delivery was performed according to World Health Organization recommendations in all study sites. Out of 4,583 culture-positive TB cases analysed, 361 (7.9%) were MDR and 64 (1.4%) were XDR. XDR-TB cases had a relative risk (RR) of 1.58 to have an unfavourable outcome compared with MDR-TB cases resistant to all first-line drugs (isoniazid, rifampicin ethambutol, streptomycin and, when tested, pyrazinamide), and an RR of 2.61 compared with "other" MDR-TB cases (those susceptible to at least one first-line anti-TB drug among ethambutol, pyrazinamide and streptomycin, regardless of resistance to the second-line drugs not defining XDR-TB). The emergence of extensively drug-resistant tuberculosis confirms that problems in tuberculosis management are still present in Europe. While waiting for new tools which will facilitate management of extensively drug-resistant tuberculosis, accessibility to quality diagnostic and treatment services should be urgently ensured and adequate public health policies should be rapidly implemented to prevent further development of drug resistance.

  6. Multimodal neuroimaging in presurgical evaluation of drug-resistant epilepsy

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2014-01-01

    Full Text Available Intracranial EEG (icEEG monitoring is critical in epilepsy surgical planning, but it has limitations. The advances of neuroimaging have made it possible to reveal epileptic abnormalities that could not be identified previously and improve the localization of the seizure focus and the vital cortex. A frequently asked question in the field is whether non-invasive neuroimaging could replace invasive icEEG or reduce the need for icEEG in presurgical evaluation. This review considers promising neuroimaging techniques in epilepsy presurgical assessment in order to address this question. In addition, due to large variations in the accuracies of neuroimaging across epilepsy centers, multicenter neuroimaging studies are reviewed, and there is much need for randomized controlled trials (RCTs to better reveal the utility of presurgical neuroimaging. The results of multiple studies indicate that non-invasive neuroimaging could not replace invasive icEEG in surgical planning especially in non-lesional or extratemporal lobe epilepsies, but it could reduce the need for icEEG in certain cases. With technical advances, multimodal neuroimaging may play a greater role in presurgical evaluation to reduce the costs and risks of epilepsy surgery, and provide surgical options for more patients with drug-resistant epilepsy.

  7. A Randomised Trial Comparing Genotypic and Virtual Phenotypic Interpretation of HIV Drug Resistance: The CREST Study

    OpenAIRE

    Hales, Gillian; Birch, Chris; Crowe, Suzanne; Workman, Cassy; Hoy, Jennifer F.; Law, Matthew G; Kelleher, Anthony D.; Lincoln, Douglas; Emery, Sean

    2006-01-01

    Editorial Commentary Background: Antiretroviral drugs are used to treat patients with HIV infection, with good evidence that they improve prognosis. However, mutations develop in the HIV genome that allow it to evade successful treatment—known as drug resistance—and such mutations are known against every class of antiretroviral drug. Resistance can cause treatment failure and limit the treatment options available. Different types of tests are often used to detect resistance and to work out wh...

  8. Studies of resistance factors against chloroethylnitrosourea drugs in malignant tumor cells

    OpenAIRE

    Egyházi, Suzanne

    1996-01-01

    Drug resistance is a major clinical problem in the chemotherapy of tumor diseases and the identification of factors that make tumor cells resistant to drug treatment is therefore of crucial importance. We have investigated a possible involvement of O6-methylguanine-DNA methyltransferase (MGMT), glutathione transferase (GST) and glutathione (GSH) in the resistance to 1,3- bis(2-chloroethyl)- 1 -nitrosourea (BCNU) in two human lung cancer cell lines. The non-small cell lung ca...

  9. Use of the Aspergillus oryzae actin gene promoter in a novel reporter system for exploring antifungal compounds and their target genes.

    Science.gov (United States)

    Marui, Junichiro; Yoshimi, Akira; Hagiwara, Daisuke; Fujii-Watanabe, Yoshimi; Oda, Ken; Koike, Hideaki; Tamano, Koichi; Ishii, Tomoko; Sano, Motoaki; Machida, Masayuki; Abe, Keietsu

    2010-08-01

    Demand for novel antifungal drugs for medical and agricultural uses has been increasing because of the diversity of pathogenic fungi and the emergence of drug-resistant strains. Genomic resources for various living species, including pathogenic fungi, can be utilized to develop novel and effective antifungal compounds. We used Aspergillus oryzae as a model to construct a reporter system for exploring novel antifungal compounds and their target genes. The comprehensive gene expression analysis showed that the actin-encoding actB gene was transcriptionally highly induced by benomyl treatment. We therefore used the actB gene to construct a novel reporter system for monitoring responses to cytoskeletal stress in A. oryzae by introducing the actB promoter::EGFP fusion gene. Distinct fluorescence was observed in the reporter strain with minimum background noise in response to not only benomyl but also compounds inhibiting lipid metabolism that is closely related to cell membrane integrity. The fluorescent responses indicated that the reporter strain can be used to screen for lead compounds affecting fungal microtubule and cell membrane integrity, both of which are attractive antifungal targets. Furthermore, the reporter strain was shown to be technically applicable for identifying novel target genes of antifungal drugs triggering perturbation of fungal microtubules or membrane integrity.

  10. Diversity and antifungal susceptibility of Norwegian Candida glabrata clinical isolates

    Science.gov (United States)

    Andersen, Kari-Mette; Kristoffersen, Anne Karin; Ingebretsen, André; Vikholt, Katharina Johnsen; Örtengren, Ulf Thore; Olsen, Ingar; Enersen, Morten; Gaustad, Peter

    2016-01-01

    Background Increasing numbers of immunocompromised patients have resulted in greater incidence of invasive fungal infections with high mortality. Candida albicans infections dominate, but during the last decade, Candida glabrata has become the second highest cause of candidemia in the United States and Northern Europe. Reliable and early diagnosis, together with appropriate choice of antifungal treatment, is needed to combat these challenging infections. Objectives To confirm the identity of 183 Candida glabrata isolates from different human body sites using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and VITEK®2, and to analyze isolate protein profiles and antifungal susceptibility. The minimum inhibitory concentration (MIC) of seven antifungal drugs was determined for the isolates to elucidate susceptibility. Design A total of 183 C. glabrata isolates obtained between 2002 and 2012 from Norwegian health-care units were analyzed. For species verification and differentiation, biochemical characterization (VITEK®2) and mass spectrometry (MALDI–TOF) were used. MIC determination for seven antifungal drugs was undertaken using E-tests®. Results Using VITEK®2, 92.9% of isolates were identified as C. glabrata, while all isolates (100%) were identified as C. glabrata using MALDI-TOF. Variation in protein spectra occurred for all identified C. glabrata isolates. The majority of isolates had low MICs to amphotericin B (≤1 mg/L for 99.5%) and anidulafungin (≤0.06 mg/L for 98.9%). For fluconazole, 18% of isolates had MICs >32 mg/L and 82% had MICs in the range ≥0.016 mg/L to ≤32 mg/L. Conclusions Protein profiles and antifungal susceptibility characteristics of the C. glabrata isolates were diverse. Clustering of protein profiles indicated that many azole resistant isolates were closely related. In most cases, isolates had highest susceptibility to amphotericin B and anidulafungin. The results confirmed previous observations of high

  11. Evaluation of efflux pump gene expression among drug susceptible and drug resistant strains of Mycobacterium tuberculosis from Iran.

    Science.gov (United States)

    Kardan Yamchi, Jalil; Haeili, Mehri; Gizaw Feyisa, Seifu; Kazemian, Hossein; Hashemi Shahraki, Abdolrazagh; Zahednamazi, Fatemeh; Imani Fooladi, Abbas Ali; Feizabadi, Mohammad Mehdi

    2015-12-01

    Absence of mutations within the genes encoding drug targets in some phenotypically drug resistant strains of Mycobacterium tuberculosis suggests possible involvement of alternative mechanisms such as over-expression of efflux pumps. We investigated the expression level of Rv1410c, Rv2459, Rv1218c and Rv1273c efflux pumps gene by real-time quantitative reverse transcription PCR (qRT-PCR) in 31 clinical isolates of M. tuberculosis. Susceptibility to first-line drugs was performed using the proportion method. Twenty one isolates were characterized with drug resistance (DR), and among them 12 showed a significantly elevated level of expression (>4 fold) for at least one of the studied genes encoding for efflux pumps. Point mutations in the katG (codons 315 or 335) and rpoB (codons 456 and 441) genes were found in 42.85% and 66.6% of drug resistant isolates, respectively. Only one isolate showed mutation at position -15 of the inhA promoter region. Among the 7 isolates (33.33%) which had no mutation in the studied regions of drug target genes, 5 isolates showed over-expression for efflux pumps. Our results demonstrated that over-expression of efflux pumps can contribute to drug resistance in M. tuberculosis.

  12. Evaluation of antifungal susceptibility testing in Candida isolates by Candifast and disk-diffusion method

    OpenAIRE

    Sidhartha Giri; Anupma Jyoti Kindo

    2014-01-01

    With the increase in invasive fungal infections due to Candida species and resistance to antifungal therapy, in vitro antifungal susceptibility testing is becoming an important part of clinical microbiology laboratories. Along with broth microdilution and disk diffusion method, various commercial methods are being increasingly used for antifungal susceptibility testing, especially in the developed world. In our study, we compared the antifungal susceptibility patterns of 39 isolates of Candid...

  13. Selective modulation of P-glycoprotein-mediated drug resistance

    OpenAIRE

    Bebawy, M; Morris, M B; Roufogalis, B. D.

    2001-01-01

    Multidrug resistance associated with the overexpression of the multidrug transporter P-glycoprotein is a serious impediment to successful cancer treatment. We found that verapamil reversed resistance of CEM/VLB 100 cells to vinblastine and fluorescein-colchicine, but not to colchicine. Chlorpromazine reversed resistance to vinblastine but not to fluorescein-colchicine, and it increased resistance to colchicine. Initial influx rates of fluorescein-colchicine were similar in resistant and paren...

  14. Overcoming ABC transporter-mediated multidrug resistance: Molecular mechanisms and novel therapeutic drug strategies.

    Science.gov (United States)

    Li, Wen; Zhang, Han; Assaraf, Yehuda G; Zhao, Kun; Xu, Xiaojun; Xie, Jinbing; Yang, Dong-Hua; Chen, Zhe-Sheng

    2016-07-01

    Multidrug resistance is a key determinant of cancer chemotherapy failure. One of the major causes of multidrug resistance is the enhanced efflux of drugs by membrane ABC transporters. Targeting ABC transporters projects a promising approach to eliminating or suppressing drug resistance in cancer treatment. To reveal the functional mechanisms of ABC transporters in drug resistance, extensive studies have been conducted from identifying drug binding sites to elucidating structural dynamics. In this review article, we examined the recent crystal structures of ABC proteins to depict the functionally important structural elements, such as domains, conserved motifs, and critical amino acids that are involved in ATP-binding and drug efflux. We inspected the drug-binding sites on ABC proteins and the molecular mechanisms of various substrate interactions with the drug binding pocket. While our continuous battle against drug resistance is far from over, new approaches and technologies have emerged to push forward our frontier. Most recent developments in anti-MDR strategies include P-gp inhibitors, RNA-interference, nano-medicines, and delivering combination strategies. With the advent of the 'Omics' era - genomics, epigenomics, transcriptomics, proteomics, and metabolomics - these disciplines play an important role in fighting the battle against chemoresistance by further unraveling the molecular mechanisms of drug resistance and shed light on medical therapies that specifically target MDR. PMID:27449595

  15. A New Aspergillus fumigatus Resistance Mechanism Conferring In Vitro Cross-Resistance to Azole Antifungals Involves a Combination of cyp51A Alterations▿

    OpenAIRE

    Mellado, E.; Garcia-Effron, G.; Alcázar-Fuoli, L.; Melchers, W J G; Verweij, P. E.; Cuenca-Estrella, M.; Rodríguez-Tudela, J L

    2007-01-01

    Fourteen Aspergillus fumigatus clinical isolates that exhibited a pattern of reduced susceptibility to triazole drugs were analyzed. The sequences of the cyp51A gene from all isolates showed the presence of a point mutation at t364a, which led to the substitution of leucine 98 for histidine (L98H), together with the presence of two copies of a 34-bp sequence in tandem in the promoter of the cyp51A gene. Quantitative expression analysis (real-time PCR) showed up to an eightfold increase in the...

  16. Label-free recognition of drug resistance via impedimetric screening of breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Bilge Eker

    Full Text Available We present a novel study on label-free recognition and distinction of drug resistant breast cancer cells (MCF-7 DOX from their parental cells (MCF-7 WT via impedimetric measurements. Drug resistant cells exhibited significant differences in their dielectric properties compared to wild-type cells, exerting much higher extracellular resistance (Rextra . Immunostaining revealed that MCF-7 DOX cells gained a much denser F-actin network upon acquiring drug resistance indicating that remodeling of actin cytoskeleton is probably the reason behind higher Rextra , providing stronger cell architecture. Moreover, having exposed both cell types to doxorubicin, we were able to distinguish these two phenotypes based on their substantially different drug response. Interestingly, impedimetric measurements identified a concentration-dependent and reversible increase in cell stiffness in the presence of low non-lethal drug doses. Combined with a profound frequency analysis, these findings enabled distinguishing distinct cellular responses during drug exposure within four concentration ranges without using any labeling. Overall, this study highlights the possibility to differentiate drug resistant phenotypes from their parental cells and to assess their drug response by using microelectrodes, offering direct, real-time and noninvasive measurements of cell dependent parameters under drug exposure, hence providing a promising step for personalized medicine applications such as evaluation of the disease progress and optimization of the drug treatment of a patient during chemotherapy.

  17. Use of Lot Quality Assurance Sampling to Ascertain Levels of Drug Resistant Tuberculosis in Western Kenya

    Science.gov (United States)

    Cohen, Ted; Zignol, Matteo; Nyakan, Edwin; Hedt-Gauthier, Bethany L.; Gardner, Adrian; Kamle, Lydia; Injera, Wilfred; Carter, E. Jane

    2016-01-01

    Objective To classify the prevalence of multi-drug resistant tuberculosis (MDR-TB) in two different geographic settings in western Kenya using the Lot Quality Assurance Sampling (LQAS) methodology. Design The prevalence of drug resistance was classified among treatment-naïve smear positive TB patients in two settings, one rural and one urban. These regions were classified as having high or low prevalence of MDR-TB according to a static, two-way LQAS sampling plan selected to classify high resistance regions at greater than 5% resistance and low resistance regions at less than 1% resistance. Results This study classified both the urban and rural settings as having low levels of TB drug resistance. Out of the 105 patients screened in each setting, two patients were diagnosed with MDR-TB in the urban setting and one patient was diagnosed with MDR-TB in the rural setting. An additional 27 patients were diagnosed with a variety of mono- and poly- resistant strains. Conclusion Further drug resistance surveillance using LQAS may help identify the levels and geographical distribution of drug resistance in Kenya and may have applications in other countries in the African Region facing similar resource constraints. PMID:27167381

  18. Use of Lot Quality Assurance Sampling to Ascertain Levels of Drug Resistant Tuberculosis in Western Kenya.

    Directory of Open Access Journals (Sweden)

    Julia Jezmir

    Full Text Available To classify the prevalence of multi-drug resistant tuberculosis (MDR-TB in two different geographic settings in western Kenya using the Lot Quality Assurance Sampling (LQAS methodology.The prevalence of drug resistance was classified among treatment-naïve smear positive TB patients in two settings, one rural and one urban. These regions were classified as having high or low prevalence of MDR-TB according to a static, two-way LQAS sampling plan selected to classify high resistance regions at greater than 5% resistance and low resistance regions at less than 1% resistance.This study classified both the urban and rural settings as having low levels of TB drug resistance. Out of the 105 patients screened in each setting, two patients were diagnosed with MDR-TB in the urban setting and one patient was diagnosed with MDR-TB in the rural setting. An additional 27 patients were diagnosed with a variety of mono- and poly- resistant strains.Further drug resistance surveillance using LQAS may help identify the levels and geographical distribution of drug resistance in Kenya and may have applications in other countries in the African Region facing similar resource constraints.

  19. Different frequencies of drug resistance mutations among HIV-1 subtypes circulating in China: a comprehensive study.

    Directory of Open Access Journals (Sweden)

    Hongshuai Sui

    Full Text Available The rapid spreading of HIV drug resistance is threatening the overall success of free HAART in China. Much work has been done on drug-resistant mutations, however, most of which were based on subtype B. Due to different genetic background, subtypes difference would have an effect on the development of drug-resistant mutations, which has already been proved by more and more studies. In China, the main epidemic subtypes are CRF07_BC, CRF08_BC, Thai B and CRF01_AE. The depiction of drug resistance mutations in those subtypes will be helpful for the selection of regimens for Chinese. In this study, the distributions difference of amino acids at sites related to HIV drug resistance were compared among subtype B, CRF01_AE, CRF07_BC and CRF08_BC strains prevalent in China. The amino acid composition of sequences belonging to different subtypes, which were obtained from untreated and treated individuals separately, were also compared. The amino acids proportions of 19 sites in RT among subtype B, CRF01_AE and CRF08_BC have significant difference in drug resistance groups (chi-square test, p<0.05. Genetic barriers analysis revealed that sites 69, 138, 181, 215 and 238 were significantly different among subtypes (Kruskal Wallis test, p<0.05. All subtypes shared three highest prevalent drug resistance sites 103, 181 and 184 in common. Many drug resistant sites in protease show surprising high proportions in almost all subtypes in drug-naïve patients. This is the first comprehensive study in China on different development of drug resistance among different subtypes. The detailed data will lay a foundation for HIV treatment regimens design and improve HIV therapy in China.

  20. Molecular characterization of drug-resistant and drug-sensitive Aspergillus isolates causing infectious keratitis

    Directory of Open Access Journals (Sweden)

    Niranjan Nayak

    2011-01-01

    Full Text Available Purpose: To study the susceptibilities of Aspergillus species against amphotericin B in infectious keratitis and to find out if drug resistance had any association with the molecular characteristics of the fungi. Materials and Methods: One hundred and sixty Aspergillus isolates from the corneal scrapings of patients with keratitis were tested for susceptibilities to amphotericin B by broth microdilution method. These included Aspergillus flavus (64 isolates, A. fumigatus (43 and A. niger (53. Fungal DNA was extracted by glass bead vertexing technique. Polymerase chain reaction (PCR assay was standardized and used to amplify the 28S rRNA gene. Single-stranded conformational polymorphism (SSCP of the PCR product was performed by the standard protocol. Results: Of the 160 isolates, 84 (52.5% showed low minimum inhibitory concentration (MIC values (≤ 1.56 μg/ml and were designated as amphotercin B-sensitive. Similarly, 76 (47.5% had high MICs (≥ 3.12 μg/ml and were categorized as amphotericin B-resistant. MIC 50 and MIC 90 values ranged between 3.12-6.25 μg/ml and 3.12-12.5 μg/ml respectively. A. flavus and A. niger showed higher MIC 50 and MIC 90 values than A. fumigatus. The SSCP pattern exhibited three extra bands (150 bp, 200 bp and 250 bp each in addition to the 260 bp amplicon. Strains (lanes 1 and 7 lacking the 150 bp band showed low MIC values (≤ 1.56 μg/ml. Conclusion: A. niger and A. flavus isolates had higher MICs compared to A. fumigatus, suggesting a high index of suspicion for amphotericin B resistance. PCR-SSCP was a good molecular tool to characterize Aspergillus phenotypes in fungal keratitis.

  1. Antifungal Activity of 14-Helical β-Peptides against Planktonic Cells and Biofilms of Candida Species

    Directory of Open Access Journals (Sweden)

    Namrata Raman

    2015-08-01

    Full Text Available Candida albicans is the most prevalent cause of fungal infections and treatment is further complicated by the formation of drug resistant biofilms, often on the surfaces of implanted medical devices. In recent years, the incidence of fungal infections by other pathogenic Candida species such as C. glabrata, C. parapsilosis and C. tropicalis has increased. Amphiphilic, helical β-peptide structural mimetics of natural antimicrobial α-peptides have been shown to exhibit specific planktonic antifungal and anti-biofilm formation activity against C. albicans in vitro. Here, we demonstrate that β-peptides are also active against clinically isolated and drug resistant strains of C. albicans and against other opportunistic Candida spp. Different Candida species were susceptible to β-peptides to varying degrees, with C. tropicalis being the most and C. glabrata being the least susceptible. β-peptide hydrophobicity directly correlated with antifungal activity against all the Candida clinical strains and species tested. While β-peptides were largely ineffective at disrupting existing Candida biofilms, hydrophobic β-peptides were able to prevent the formation of C. albicans, C. glabrata, C. parapsilosis and C. tropicalis biofilms. The broad-spectrum antifungal activity of β-peptides against planktonic cells and in preventing biofilm formation suggests the promise of this class of molecules as therapeutics.

  2. Antifungal Activity of 14-Helical β-Peptides against Planktonic Cells and Biofilms of Candida Species.

    Science.gov (United States)

    Raman, Namrata; Lee, Myung-Ryul; Lynn, David M; Palecek, Sean P

    2015-01-01

    Candida albicans is the most prevalent cause of fungal infections and treatment is further complicated by the formation of drug resistant biofilms, often on the surfaces of implanted medical devices. In recent years, the incidence of fungal infections by other pathogenic Candida species such as C. glabrata, C. parapsilosis and C. tropicalis has increased. Amphiphilic, helical β-peptide structural mimetics of natural antimicrobial α-peptides have been shown to exhibit specific planktonic antifungal and anti-biofilm formation activity against C. albicans in vitro. Here, we demonstrate that β-peptides are also active against clinically isolated and drug resistant strains of C. albicans and against other opportunistic Candida spp. Different Candida species were susceptible to β-peptides to varying degrees, with C. tropicalis being the most and C. glabrata being the least susceptible. β-peptide hydrophobicity directly correlated with antifungal activity against all the Candida clinical strains and species tested. While β-peptides were largely ineffective at disrupting existing Candida biofilms, hydrophobic β-peptides were able to prevent the formation of C. albicans, C. glabrata, C. parapsilosis and C. tropicalis biofilms. The broad-spectrum antifungal activity of β-peptides against planktonic cells and in preventing biofilm formation suggests the promise of this class of molecules as therapeutics. PMID:26287212

  3. Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

    NARCIS (Netherlands)

    L.M. Hofstra (L. Marije); N. Sauvageot (Nicolas); J. Albert (Jan); I. Alexiev (Ivailo); F. Garcia (Federico); D. Struck (Daniel); D.A.M.C. van de Vijver (David); B. Asjö (Birgitta); D. Beshkov (Danail); S. Coughlan (Suzie); D. Descamps (Diane); A. Griskevicius (Algis); O. Hamouda (Osamah); A. Horban (Andrzej); M.E.E. van Kasteren (Marjo); T. Kolupajeva (Tatjana); L.G. Kostrikis (Leondios); K. Liitsola (Kirsi); M. Linka (Marek); O. Mor (Orna); C. Nielsen (Claus); D. Otelea (Dan); D. Paraskevis (Dimitrios); R. Paredes (Roger); M. Poljak (Mario); E. Puchhammer-Stockl E. (E.); A. Sonnerborg (Anders); D. Stanekova (Danica); M. Stanojevic (Maja); K. Van Laethem (Kristel); M. Zazzi (Maurizio); S. Zidovec Lepej (Snjezana); C.A.B. Boucher (Charles A. B.); J.-C. Schmit (Jean-Claude); A.M.J. Wensing (Annemarie); E. Puchhammer-Stöckl (Elisabeth); M. Sarcletti (M.); B. Schmied (B.); M. Geit (M.); G. Balluch (G.); A.-M. Vandamme; J. Vercauteren (Jurgen); I. Derdelinckx; A. Sasse; M. Bogaert; H. Ceunen (H.); A. de Roo (Annie); S. De Wit; F. Echahidi (F.); K. Fransen; J.-C. Goffard (J.); P. Goubau; E. Goudeseune (E.); J.-C. Yombi (J.); P. Lacor; C. Liesnard (C.); M. Moutschen; L.A. Pierard; R. Rens (R.); J. Schrooten; D. Vaira; L.P.R. Vandekerckhove; A. van den Heuvel (A.); B. van der Gucht (B.); M. Van Ranst; E. Van Wijngaerden; B. Vandercam; M. Vekemans; C. Verhofstede; N. Clumeck (N.); K. van Laethem (Kristel); D. Beshkov; I. Alexiev; S.Z. Lepej (Snjezana); J. Begovac; L.G. Kostrikis (Leondios); I. Demetriades (I.); I. Kousiappa (Ioanna); V.L. Demetriou (Victoria); J. Hezka (Johana); M. Linka; M. Maly; L. MacHala; C. Nielsen; L.B. Jørgensen; J. Gerstoft (J.); L. Mathiesen (L.); C. Pedersen (Court); H. Nielsen; A. Laursen (A.); B. Kvinesdal (B.); K. Liitsola (Kirsi); M. Ristola (M.); J. Suni; J. Sutinen (J.); D. Descamps; L. Assoumou; G. Castor; M. Grude; P. Flandre; A. Storto; O. Hamouda (Osamah); C. K̈ucherer (C.); T. Berg; P. Braun; G. Poggensee; M. Daumer (Martin); J. Eberle; H. Heiken; R. Kaiser; H. Knechten (H.); K. Korn; H. Müller; S. Neifer; B. Schmidt; H. Walter; B. Gunsenheimer-Bartmeyer (B.); T. Harrer (T.); D. Paraskevis (Dimitrios); A. Hatzakis (Angelos); A. Zavitsanou (A.); A. Vassilakis; M. Lazanas; L. Chini; A. Lioni; V. Sakka (V.); S. Kourkounti (S.); V. Paparizos (V.); A. Antoniadou (A.); A. Papadopoulos; G. Poulakou; I. Katsarolis; K. Protopapas; G. Chryssos (G.); S. Drimis (S.); P. Gargalianos; G. Xylomenos; G. Lourida; M. Psichogiou (M.); G.L. Daikos (G.); N.V. Sipsas; A. Kontos (Angelos); M.N. Gamaletsou; G. Koratzanis (G.); H. Sambatakou; H. Mariolis; A. Skoutelis; V. Papastamopoulos; O. Georgiou; P. Panagopoulos (P.); E. Maltezos; S. Coughlan (Suzie); C. de Gascun (Cillian); C. Byrne; M. Duffy; P. Bergin; D. Reidy; G. Farrell; J. Lambert; E. O'Connor; A. Rochford; J. Low; P. Coakely (P.); S. O'Dea; W. Hall; O. Mor; I. Levi (I.); D. Chemtob (D.); Z. Grossman (Zehava); M. Zazzi; A. de Luca (Andrea); C. Balotta (Claudia); C. Riva (Chiara); C. Mussini (C.); I. Caramma (I.); A. Capetti (A.); M. Colombo (Massimo); C. Rossi; F. Prati (Francesco); F. Tramuto; F. Vitale (F.); M. Ciccozzi; G. Angarano (Guiseppe); G. Rezza (G.); T. Kolupajeva; O. Vasins; A. Griskevicius (Algis); V. Lipnickiene; J.C. Schmit; D. Struck (Daniel); N. Sauvageot; R. Hemmer (R.); V. Arendt (V.); C. Michaux; T. Staub (T.); C. Sequin-Devaux; A.M.J. Wensing (Annemarie); C.A.B. Boucher (Charles); D.A.M.C. van de Vijver (David); A. Van Kessel; P.H.M. Van Bentum; K. Brinkman; B.J. Connell; M.E. van der Ende (Marchina); I.M. Hoepelman (Ilja Mohandas); M.E.E. van Kasteren (Marjo); M. Kuipers; N. Langebeek (Nienke); C. Richter; R.M.W.J. Santegoets (R. M W J); L. Schrijnders-Gudde (L.); R. Schuurman; B.J.M. van de Ven (B. J M); B. Åsjö (Birgitta); A.-M.B. Kran (A.-M. Bakken); V. Ormaasen (Vidar); P. Aavitsland (P.); A. Horban (Andrzej); J. Stanczak (J.); G.P. Stanczak (G.); E. Firlag-Burkacka (E.); A. Wiercinska-Drapalo; E. Jablonowska (E.); E. Maolepsza; M. Leszczyszyn-Pynka (M.); W. Szata (W.); R.J. Camacho (Ricardo Jorge); A. de Palma (Andre); F. Borges (F.); T. Paixão; V. Duque (V.); F. Araújo; D. Otelea; C. Paraschiv (Corina); A.M. Tudor; R. Cernat; C. Chiriac; F. Dumitrescu; L.J. Prisecariu; M. Stanojevic (Maja); D.J. Jevtovic (D.); D. Salemovic (D.); D. Stanekova; M. Habekova (M.); Z. Chabadová; T. Drobkova; P. Bukovinova; A. Shunnar; P. Truska; M. Poljak (Mario); M.M. Lunar (Maja M.); D. Babic; J. Tomazic (J.); S. Vidmar (Suzanna); T. Vovko; P. Karner (P.); F. Garcia; R. Paredes (Roger); S. Monge; S. Moreno; J. Del Amo; V. Asensi; J.L. Sirvent

    2016-01-01

    textabstractBackground. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, the

  4. Whole-Genome Sequencing Analysis of Serially Isolated Multi-Drug and Extensively Drug Resistant Mycobacterium tuberculosis from Thai Patients.

    Science.gov (United States)

    Faksri, Kiatichai; Tan, Jun Hao; Disratthakit, Areeya; Xia, Eryu; Prammananan, Therdsak; Suriyaphol, Prapat; Khor, Chiea Chuen; Teo, Yik-Ying; Ong, Rick Twee-Hee; Chaiprasert, Angkana

    2016-01-01

    Multi-drug and extensively drug-resistant tuberculosis (MDR and XDR-TB) are problems that threaten public health worldwide. Only some genetic markers associated with drug-resistant TB are known. Whole-genome sequencing (WGS) is a promising tool for distinguishing between re-infection and persistent infection in isolates taken at different times from a single patient, but has not yet been applied in MDR and XDR-TB. We aim to detect genetic markers associated with drug resistance and distinguish between reinfection and persistent infection from MDR and XDR-TB patients based on WGS analysis. Samples of Mycobacterium tuberculosis (n = 7), serially isolated from 2 MDR cases and 1 XDR-TB case, were retrieved from Siriraj Hospital, Bangkok. The WGS analysis used an Illumina Miseq sequencer. In cases of persistent infection, MDR-TB isolates differed at an average of 2 SNPs across the span of 2-9 months whereas in the case of reinfection, isolates differed at 61 SNPs across 2 years. Known genetic markers associated with resistance were detected from strains susceptible to streptomycin (2/7 isolates), p-aminosalicylic acid (3/7 isolates) and fluoroquinolone drugs. Among fluoroquinolone drugs, ofloxacin had the highest phenotype-genotype concordance (6/7 isolates), whereas gatifloxcain had the lowest (3/7 isolates). A putative candidate SNP in Rv2477c associated with kanamycin and amikacin resistance was suggested for further validation. WGS provided comprehensive results regarding molecular epidemiology, distinguishing between persistent infection and reinfection in M/XDR-TB and potentially can be used for detection of novel mutations associated with drug resistance. PMID:27518818

  5. Adaptive Landscape by Environment Interactions Dictate Evolutionary Dynamics in Models of Drug Resistance.

    Directory of Open Access Journals (Sweden)

    C Brandon Ogbunugafor

    2016-01-01

    Full Text Available The adaptive landscape analogy has found practical use in recent years, as many have explored how their understanding can inform therapeutic strategies that subvert the evolution of drug resistance. A major barrier to applications of these concepts is a lack of detail concerning how the environment affects adaptive landscape topography, and consequently, the outcome of drug treatment. Here we combine empirical data, evolutionary theory, and computer simulations towards dissecting adaptive landscape by environment interactions for the evolution of drug resistance in two dimensions-drug concentration and drug type. We do so by studying the resistance mediated by Plasmodium falciparum dihydrofolate reductase (DHFR to two related inhibitors-pyrimethamine and cycloguanil-across a breadth of drug concentrations. We first examine whether the adaptive landscapes for the two drugs are consistent with common definitions of cross-resistance. We then reconstruct all accessible pathways across the landscape, observing how their structure changes with drug environment. We offer a mechanism for non-linearity in the topography of accessible pathways by calculating of the interaction between mutation effects and drug environment, which reveals rampant patterns of epistasis. We then simulate evolution in several different drug environments to observe how these individual mutation effects (and patterns of epistasis influence paths taken at evolutionary "forks in the road" that dictate adaptive dynamics in silico. In doing so, we reveal how classic metrics like the IC50 and minimal inhibitory concentration (MIC are dubious proxies for understanding how evolution will occur across drug environments. We also consider how the findings reveal ambiguities in the cross-resistance concept, as subtle differences in adaptive landscape topography between otherwise equivalent drugs can drive drastically different evolutionary outcomes. Summarizing, we discuss the results with

  6. Adaptive Landscape by Environment Interactions Dictate Evolutionary Dynamics in Models of Drug Resistance.

    Science.gov (United States)

    Ogbunugafor, C Brandon; Wylie, C Scott; Diakite, Ibrahim; Weinreich, Daniel M; Hartl, Daniel L

    2016-01-01

    The adaptive landscape analogy has found practical use in recent years, as many have explored how their understanding can inform therapeutic strategies that subvert the evolution of drug resistance. A major barrier to applications of these concepts is a lack of detail concerning how the environment affects adaptive landscape topography, and consequently, the outcome of drug treatment. Here we combine empirical data, evolutionary theory, and computer simulations towards dissecting adaptive landscape by environment interactions for the evolution of drug resistance in two dimensions-drug concentration and drug type. We do so by studying the resistance mediated by Plasmodium falciparum dihydrofolate reductase (DHFR) to two related inhibitors-pyrimethamine and cycloguanil-across a breadth of drug concentrations. We first examine whether the adaptive landscapes for the two drugs are consistent with common definitions of cross-resistance. We then reconstruct all accessible pathways across the landscape, observing how their structure changes with drug environment. We offer a mechanism for non-linearity in the topography of accessible pathways by calculating of the interaction between mutation effects and drug environment, which reveals rampant patterns of epistasis. We then simulate evolution in several different drug environments to observe how these individual mutation effects (and patterns of epistasis) influence paths taken at evolutionary "forks in the road" that dictate adaptive dynamics in silico. In doing so, we reveal how classic metrics like the IC50 and minimal inhibitory concentration (MIC) are dubious proxies for understanding how evolution will occur across drug environments. We also consider how the findings reveal ambiguities in the cross-resistance concept, as subtle differences in adaptive landscape topography between otherwise equivalent drugs can drive drastically different evolutionary outcomes. Summarizing, we discuss the results with regards to their

  7. Adaptive Landscape by Environment Interactions Dictate Evolutionary Dynamics in Models of Drug Resistance

    Science.gov (United States)

    Ogbunugafor, C. Brandon; Wylie, C. Scott; Diakite, Ibrahim; Weinreich, Daniel M.; Hartl, Daniel L.

    2016-01-01

    The adaptive landscape analogy has found practical use in recent years, as many have explored how their understanding can inform therapeutic strategies that subvert the evolution of drug resistance. A major barrier to applications of these concepts is a lack of detail concerning how the environment affects adaptive landscape topography, and consequently, the outcome of drug treatment. Here we combine empirical data, evolutionary theory, and computer simulations towards dissecting adaptive landscape by environment interactions for the evolution of drug resistance in two dimensions—drug concentration and drug type. We do so by studying the resistance mediated by Plasmodium falciparum dihydrofolate reductase (DHFR) to two related inhibitors—pyrimethamine and cycloguanil—across a breadth of drug concentrations. We first examine whether the adaptive landscapes for the two drugs are consistent with common definitions of cross-resistance. We then reconstruct all accessible pathways across the landscape, observing how their structure changes with drug environment. We offer a mechanism for non-linearity in the topography of accessible pathways by calculating of the interaction between mutation effects and drug environment, which reveals rampant patterns of epistasis. We then simulate evolution in several different drug environments to observe how these individual mutation effects (and patterns of epistasis) influence paths taken at evolutionary “forks in the road” that dictate adaptive dynamics in silico. In doing so, we reveal how classic metrics like the IC50 and minimal inhibitory concentration (MIC) are dubious proxies for understanding how evolution will occur across drug environments. We also consider how the findings reveal ambiguities in the cross-resistance concept, as subtle differences in adaptive landscape topography between otherwise equivalent drugs can drive drastically different evolutionary outcomes. Summarizing, we discuss the results with

  8. STUDIES ON ANTIBACTERIAL EFFECT OF APAMARGA (ACHYRANTHES ASPERA ON MULTI-DRUG RESISTANT CLINICAL ISOLATES

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    Patil Usha

    2013-04-01

    Full Text Available Recent reports on emergence of multidrug resistant bacteria are cause of concern in medical world. Several ayurvedic drugs have been proved to contain the antimicrobial activity. Literature on effect of ayurvedic drugs on multidrug resistant bacterial pathogens is limited. Present study reports the antimicrobial effect of Achyranthes aspera (Apamarga crude extracts on the clinical isolates of multidrug resistant bacteria. The drug was evaluated by using phytochemical tests. Crude extracts of aqueous, methanol, ethanol and chloroform was prepared. Antibacterial activity against clinically isolated multidrug resistant bacteria belonging to groups of bacillus, citrobacter, E.coli, klebsiella, proteus and salmonella was tested. The drug showed highest efficacy against Bacillus organism while least effectiveness on Proteus spp bacteria. Results of the study conclude that the medicinal plant A. aspera might be useful against multidrug resistance in pathogens of clinical importance.

  9. Trends of drug resistant Mycobacterium Tuberculosis in a tertiary tuberculosis center in Iran

    International Nuclear Information System (INIS)

    To determine the drug resistance pattern to first line antituberculosis drugs in National Research Institute of Tuberculosis and Lung Disease and to compare resistant rates with the previous studies. An anterograde cross-sectional study was performed. The study includes all adults with documented pulmonary tuberculosis (TB) that were hospitalized in National Research Institute of Tuberculosis and Lung Disease, Tehran from June 2003 to September 2004. Demographic characteristic, TB categories, and drug susceptibility tests were recorded. Two previous studies regarding susceptibility in Iran were selected as historical controls. One hundred and ninety-six new cases and 68 previously treated patients were enrolled in the study. The strains of 61% of new patients and 21% of previously treated patients were fully sensitive to all drugs. The most common resistance was streptomycin (27%) followed by isoniazid (23%) in new cases. Multiple drug resistant strains were noted in 2.6% (95% CI 0.8% to 5.8%) of new cases versus 56% (95% CI 43% to 68%) in previously treated group. The frequency of primary drug resistance to isoniazid was 98%-15% or streptomycin 9.8%-15% or streptomycin 9.8%-13% in the previous studies (p<0.00001). While these rates may not reflect the true prevalence of drug resistance on national scale, it does partially demonstrate some defects in the existing tuberculosis control program. The significant increase of isoniazid and streptomycin resistance in the last few years would present a serious challenge to effective management of TB. (author)

  10. Prevalenoe of Drug - Resistant Staphylococci in Teheran University Hospital Wards

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    F. Shafa

    1960-01-01

    Full Text Available 1 Fifty coagulase posittve strains of staphylococc~~ ~folated fr.o~ .the nose"nand wrist of Hospital nurses have been examined for sensltfvlty to pemcilhn, tetracyclines,"nchloramphenicol, dihydrostreptomycin, erythrorriycm, neomycin, kana.n:ycin,"nbacitracin, polymyxin-B and the triple sulfa. The percentages of fully sensittve strains at the present are as followe:                                       Erythromycin                                       100%"nNeomycin                                             78%"nKanamycin                                            78%"nChloramphenicol                                     68%"nDihydrostreptomycin                               52%"nPenicillin                                                18%"nTetracyclines                                         16%"nPolymyxin-B                                            1%"nTriple sulfa                                              0%"n2 The following topics have been discussed:"na The origin anr" mechanism of drug resistance"nb Cross-resistr.nee"nc The hospital epidemiology of Staphylococcus"nd The clinical implications of Staphylococcus drug-resistance

  11. Treatment of complicated intra-abdominal infections in the era of multi-drug resistant Bacteria

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    Herzog T

    2010-11-01

    Full Text Available Abstract The management of severe intra-abdominal infections remains a major challenge facing surgeons and intensive care physicians, because of its association with high morbidity and mortality. Surgical management and intensive care medicine have constantly improved, but in the recent years a rapidly continuing emergence of resistant pathogens led to treatment failure secondary to infections with multi-drug resistant bacteria. In secondary peritonitis the rate of resistant germs at the initial operation is already 30%. The lack of effective antibiotics against these pathogens resulted in the development of new broad-spectrum compounds and antibiotics directed against resistant germs. But so far no "super-drug" with efficacy against all resistant bacteria exists. Even more, soon after their approval, reports on resistance against these novel drugs have been reported, or the drugs were withdrawn from the market due to severe side effects. Since pharmaceutical companies reduced their investigations on antibiotic research, only few new antimicrobial derivates are available. In abdominal surgery you may be in fear that in the future more and more patients with tertiary peritonitis secondary to multi-drug resistant species are seen with an increase of mortality after secondary peritonitis. This article reviews the current treatment modalities for complicated intra-abdominal infections with special reference to the antibiotic treatment of complicated intra-abdominal infections with multi-drug resistant species.

  12. In vitro antifungal and antibiofilm activities of halogenated quinoline analogues against Candida albicans and Cryptococcus neoformans.

    Science.gov (United States)

    Zuo, Ran; Garrison, Aaron T; Basak, Akash; Zhang, Peilan; Huigens, Robert W; Ding, Yousong

    2016-08-01

    With the increasing prevalence of fungal infections coupled with emerging drug resistance, there is an urgent need for new and effective antifungal agents. Here we report the antifungal activities of 19 diverse halogenated quinoline (HQ) small molecules against Candida albicans and Cryptococcus neoformans. Four HQ analogues inhibited C. albicans growth with a minimum inhibitory concentration (MIC) of 100 nM, whilst 16 analogues effectively inhibited C. neoformans at MICs of 50-780 nM. Remarkably, two HQ analogues eradicated mature C. albicans and C. neoformans biofilms [minimum biofilm eradication concentration (MBEC) = 6.25-62.5 µM]. Several active HQs were found to penetrate into fungal cells, whilst one inactive analogue was unable to, suggesting that HQs elicit their antifungal activities through an intracellular mode of action. HQs are a promising class of small molecules that may be useful in future antifungal treatments. PMID:27256584

  13. [Erythropoietin and drug resistance in breast and ovarian cancers].

    Science.gov (United States)

    Szenajch, Jolanta M; Synowiec, Agnieszka E

    2016-01-01

    Recombinant human erythropoietin (rhEPO) is used in breast and ovarian cancer patients to alleviate cancer- and chemotherapy-related anemia. Some clinical trials have reported that rhEPO may adversely impact survival and increase the risk of thrombovascular events in patients with breast cancer but not with ovarian cancer. The latter may potentially benefit the most from rhEPO treatment due to the nephrotoxic and myelosuppresive effects of standard platinum-based chemotherapy used in ovarian cancer disease. However, over the last decade the preclinical data have revealed that EPO is not only the principal growth factor and the hormone which regulates erythropoiesis, but also a cytokine with a pleiotropic activity which also can affect cancer cells. EPO can stimulate survival, ability to form metastases and drug resistance not only in continuous breast- and ovarian cancer cell lines but also in breast cancer stem-like cells. EPO receptor (EPOR) can also be constitutively active in both these cancers and, in breast cancer cells, may act in an interaction with estrogen receptor (ER) and epidermal growth factor receptor-2 (HER-2). EPOR, by an EPO-independent mechanism, promotes proliferation of breast cancer cells in cooperation with estrogen receptor, resulting in decreased effectiveness of tamoxifen treatment. In another interaction, as a result of the molecular antagonism between EPOR and HER2, rhEPO protects breast cancer cells against trastuzumab. Both clinical and preclinical evidence strongly suggest the urgent need to reevaluate the traditional use of rhEPO in the oncology setting. PMID:27321103

  14. Differential Persistence of Transmitted HIV-1 Drug Resistance Mutation Classes

    Science.gov (United States)

    Jain, Vivek; Sucupira, Maria C.; Bacchetti, Peter; Hartogensis, Wendy; Diaz, Ricardo S.; Kallas, Esper G.; Janini, Luiz M.; Liegler, Teri; Pilcher, Christopher D.; Grant, Robert M.; Cortes, Rodrigo; Deeks, Steven G.

    2011-01-01

    Background. Transmitted human immunodeficiency virus type 1 (HIV-1) drug resistance (TDR) mutations can become replaced over time by emerging wild-type viral variants with improved fitness. The impact of class-specific mutations on this rate of mutation replacement is uncertain. Methods. We studied participants with acute and/or early HIV infection and TDR in 2 cohorts (San Francisco, California, and São Paulo, Brazil). We followed baseline mutations longitudinally and compared replacement rates between mutation classes with use of a parametric proportional hazards model. Results. Among 75 individuals with 195 TDR mutations, M184V/I became undetectable markedly faster than did nonnucleoside reverse-transcriptase inhibitor (NNRTI) mutations (hazard ratio, 77.5; 95% confidence interval [CI], 14.7–408.2; P < .0001), while protease inhibitor and NNRTI replacement rates were similar. Higher plasma HIV-1 RNA level predicted faster mutation replacement, but this was not statistically significant (hazard ratio, 1.71 log10 copies/mL; 95% CI, .90–3.25 log10 copies/mL; P = .11). We found substantial person-to-person variability in mutation replacement rates not accounted for by viral load or mutation class (P < .0001). Conclusions. The rapid replacement of M184V/I mutations is consistent with known fitness costs. The long-term persistence of NNRTI and protease inhibitor mutations suggests a risk for person-to-person propagation. Host and/or viral factors not accounted for by viral load or mutation class are likely influencing mutation replacement and warrant further study. PMID:21451005