Vasundhra Bhandari

Bio: Vasundhra Bhandari is an academic researcher from Department of Biotechnology. The author has contributed to research in topics: Medicine & Leishmania donovani. The author has an hindex of 14, co-authored 31 publications receiving 609 citations. Previous affiliations of Vasundhra Bhandari include Indian Council of Medical Research & University of Hyderabad.

Drug susceptibility in Leishmania isolates following miltefosine treatment in cases of visceral leishmaniasis and post kala-azar dermal leishmaniasis.

Abstract: Background With widespread resistance to antimonials in Visceral Leishmaniasis (VL) in the Indian subcontinent, Miltefosine (MIL) has been introduced as the first line therapy. Surveillance of MIL susceptibility in natural populations of Leishmania donovani is vital to preserve it and support the VL elimination program.

Increased miltefosine tolerance in clinical isolates of Leishmania donovani is associated with reduced drug accumulation, increased infectivity and resistance to oxidative stress.

Abstract: Background Miltefosine (MIL) is an oral antileishmanial drug used for treatment of visceral leishmaniasis (VL) in the Indian subcontinent. Recent reports indicate a significant decline in its efficacy with a high rate of relapse in VL as well as post kala-azar dermal leishmaniasis (PKDL). We investigated the parasitic factors apparently involved in miltefosine unresponsiveness in clinical isolates of Leishmania donovani. Methodology L. donovani isolated from patients of VL and PKDL at pretreatment stage (LdPreTx, n = 9), patients that relapsed after MIL treatment (LdRelapse, n = 7) and parasites made experimentally resistant to MIL (LdM30) were included in this study. MIL uptake was estimated using liquid chromatography coupled mass spectrometry. Reactive oxygen species and intracellular thiol content were measured fluorometrically. Q-PCR was used to assess the differential expression of genes associated with MIL resistance. Results LdRelapse parasites exhibited higher IC50 both at promastigote level (7.92 ± 1.30 μM) and at intracellular amastigote level (11.35 ± 6.48 μM) when compared with LdPreTx parasites (3.27 ± 1.52 μM) and (3.85 ± 3.11 μM), respectively. The percent infectivity (72 hrs post infection) of LdRelapse parasites was significantly higher (80.71 ± 5.67%, P<0.001) in comparison to LdPreTx (60.44 ± 2.80%). MIL accumulation was significantly lower in LdRelapse parasites (1.7 fold, P<0.001) and in LdM30 parasites (2.4 fold, P<0.001) when compared with LdPreTx parasites. MIL induced ROS levels were significantly lower (p<0.05) in macrophages infected with LdRelapse while intracellular thiol content were significantly higher in LdRelapse compared to LdPreTx, indicating a better tolerance for oxidative stress in LdRelapse isolates. Genes associated with oxidative stress, metabolic processes and transporters showed modulated expression in LdRelapse and LdM30 parasites in comparison with LdPreTx parasites. Conclusion The present study highlights the parasitic factors and pathways responsible for miltefosine unresponsiveness in VL and PKDL.

Elucidation of Cellular Mechanisms Involved in Experimental Paromomycin Resistance in Leishmania donovani

Abstract: Leishmania donovani is the causative agent of the potentially fatal disease visceral leishmaniasis (VL). Chemotherapeutic options available to treat VL are limited and often face parasite resistance, inconsistent efficacy, and toxic side effects. Paromomycin (PMM) was recently introduced to treat VL as a monotherapy and in combination therapy. It is vital to understand the mechanisms of PMM resistance to safeguard the drug. In the present study, we utilized experimentally generated PMM-resistant L. donovani to elucidate the mechanisms of resistance and parasite biology. We found increased membrane fluidity accompanied by decreased intracellular drug accumulation in the PMM-resistant parasites. There were marked increases in gene expression of ATP-binding cassette (ABC) transporters (MDR1 and MRPA) and protein phosphatase 2A that evince increased drug efflux. Further, evaluation of parasite tolerance toward host leishmanicidal mechanisms revealed PMM-resistant parasites as being more tolerant to nitrosative stress at the promastigote and amastigote stages. The PMM-resistant parasites also predicted a better survival capacity, as indicated by resistance to complement-mediated lysis and increased stimulation of host interleukin-10 (IL-10) expression. The susceptibilities of PMM-resistant isolates to other antileishmanial agents (sodium antimony gluconate and miltefosine) remained unchanged. The data implicated the roles of altered membrane fluidity, decreased drug accumulation, increased expression of ABC transporters, and greater tolerance of parasites to host defense mechanisms in conferring PMM resistance in Leishmania.

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India

Abstract: Bovine mastitis caused by multidrug resistant Staphylococcus aureus is a huge problem reported worldwide, resulting in prolonged antibiotic treatment and death of livestock. The current study is focused on surveillance of antibiotic susceptibility along with genotypic and phenotypic characterization of the pathogenic S. aureus strains causing mastitis in India. One hundred and sixty seven milk samples were collected from mastitis-affected cows from different farms in India resulting in thirty nine isolated S. aureus strains. Antibiotic sensitivity profiling revealed the majority of the strains (n = 24) to be multidrug resistant and eleven strains showed reduced susceptibility to vancomycin (MICs = 2μg/ml). All strains were oxacillin sensitive, but 19 strains were positive for the mecA gene, which revealed the occurrence of oxacillin susceptible mecA positive strains (OS-MRSA) for the first time from India. Additionally, 32 strains were positive for the pvl gene, a virulence determinant; of these 17 were also OS-MRSA strains. Molecular characterization based on multilocus sequence typing (MLST), spa typing, agr typing and SCCmec classification revealed strains belonging to different groups. Moreover, strains showed spa types (t2526, t9602) and MLST sequence types, ST-72, ST-88 and ST-239 which have been earlier reported in human infections. The prevalence of OS-MRSA strains indicates the importance of including both the genetic and phenotypic tests in characterizing S. aureus strains. Increased genotypic variability with strain related to human infections and pvl positive isolates indicates a worrisome situation with the possibility of bilateral transfer.

Validation of a simple resazurin-based promastigote assay for the routine monitoring of miltefosine susceptibility in clinical isolates of Leishmania donovani.

Abstract: Simple, cost-effective approach for routine surveillance of parasite susceptibility to antileishmanial drug miltefosine (MIL) is highly desirable for controlling emergence of drug resistance in visceral leishmaniasis (VL). We validated a simple resazurin-based fluorimetric assay using promastigotes to track natural MIL tolerance in Leishmania donovani parasites from VL cases (n = 17) against standard amastigote assay, in two different labs in India. The inter-stage MIL susceptibility correlated strongly (r = 0.70, p = 0.0018) using J774.A.1 macrophage cell line-based amastigote assay and fluorescence-based resazurin assay for promastigotes. Investigation of inter-stage MIL susceptibility for the same set of clinical isolates in another lab also showed a strong correlation (r = 0.72, p = 0.0012) using mouse peritoneal macrophages for amastigote assay and resazurin-based alamar blue assay for promastigotes. Additionally, parasites from post-kala-azar dermal leishmaniasis (PKDL) lesions (n = 7, r = 0.78, p = 0.046) and MIL-induced parasites (r = 0.92, p = 0.0001; n = 3) also exhibited a strongly correlated inter-stage miltefosine susceptibility. Thus, our results support the utility of resazurin assay as a simplified biological tool for MIL susceptibility monitoring in clinical isolates from MIL-treated VL/PKDL patients.

SPAdes, a new genome assembly algorithm and its applications to single-cell sequencing ( 7th Annual SFAF Meeting, 2012)

Abstract: The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

What is Veterinary Medicine

Abstract: Transfer Requirements The following requirements for the major are subject to change without notice. To assure accuracy of the information on this sheet, you should consult with a counselor, the articulation officer, or review articulation agreements via the internet at www.assist.org Veterinary medicine uses problem-solving skills and in-depth knowledge to diagnose, treat and prevent animal diseases. It is the broadest and most comprehensive of all the health professions. The profession is concerned with enhancing the health, welfare, and productivity of animals and assuring the safety of animal products used by people. Veterinarians are highly trained medical professionals who provide for the health needs of all kinds of animals while maintaining sensitivity to human health and well-being. Most veterinarians in the United States are engaged in private practice. Other veterinarians work in a wide range of fields relating to public health, animal disease control, environmental protection, the biotechnology industry, higher education and research. Academic preparation for veterinary school takes place at the undergraduate level through a comprehensive educational experience with special emphasis in the sciences. In order to succeed academically, in the rigorous veterinary school curriculum, veterinary schools are looking for individuals with a highly developed science background. Since Pre-Veterinary is not a major, it is important to meet with a counselor during your first semester at El Camino College to help with the selection of classes. 1. Academic preparation and grade point average is critical for admission. Cumulative GPA, strong grades in science courses, and GPA in the last two years of undergraduate study are critical in the selection process. 2. Many, but not all veterinary schools require a bachelor's degree. In some instances, a bachelor's degree may make an applicant more competitive in the admission process. 3. Score on a standardized graduate admissions test (e.g. GRE, MCAT, and VCAT). Check with the individual program for the specific test required. 4. Strong letters of recommendation-Most schools require a minimum of three letters of recommendation. Some schools require on letter from a Doctor of Veterinary Medicine. 5. Undergraduate course of study-Veterinary schools are looking for both lower and upper division preparation. 6. Applicant's personal statement or narrative. 7. Extracurricular activities, work experience, community activities, motivation, individual character, personality, and other post-undergraduate experiences. 8. Animal related activities and/or animal related work experience-Most colleges are looking for a strong commitment to working with animals. Some require employment by a Veterinarian. 9. Personal interview. …

Drug resistance and treatment failure in leishmaniasis: A 21st century challenge

Abstract: Reevaluation of treatment guidelines for Old and New World leishmaniasis is urgently needed on a global basis because treatment failure is an increasing problem. Drug resistance is a fundamental determinant of treatment failure, although other factors also contribute to this phenomenon, including the global HIV/AIDS epidemic with its accompanying impact on the immune system. Pentavalent antimonials have been used successfully worldwide for the treatment of leishmaniasis since the first half of the 20th century, but the last 10 to 20 years have witnessed an increase in clinical resistance, e.g., in North Bihar in India. In this review, we discuss the meaning of “resistance” related to leishmaniasis and discuss its molecular epidemiology, particularly for Leishmania donovani that causes visceral leishmaniasis. We also discuss how resistance can affect drug combination therapies. Molecular mechanisms known to contribute to resistance to antimonials, amphotericin B, and miltefosine are also outlined.

Increasing Failure of Miltefosine in the Treatment of Kala-azar in Nepal and the Potential Role of Parasite Drug Resistance, Reinfection, or Noncompliance

Abstract: Background. Miltefosine (MIL), the only oral drug for visceral leishmaniasis (VL), is currently the first-line therapy in the VL elimination program of the Indian subcontinent. Given the paucity of anti-VL drugs and the looming threat of resistance, there is an obvious need for close monitoring of clinical efficacy of MIL. Methods. In a cohort study of 120 VL patients treated with MIL in Nepal, we monitored the clinical outcomes up to 12 months after completion of therapy and explored the potential role of drug compliance, parasite drug resistance, and reinfection. Results. The initial cure rate was 95.8% (95% confidence interval [CI], 92.2−99.4) and the relapse rate at 6 and 12 months was 10.8% (95% CI, 5.2−16.4) and 20.0% (95% CI, 12.8−27.2) , respectively. No significant clinical risk factors of relapse apart from age <12 years were found. Parasite fingerprints of pretreatment and relapse bone marrow isolates within 8 patients were similar, suggesting that clinical relapses were not due to reinfection with a new strain. The mean promastigote MIL susceptibility (50% inhibitory concentration) of isolates from definite cures was similar to that of relapses. Although more tolerant strains were observed, parasite resistance, as currently measured, is thus not likely involved in MIL treatment failure. Moreover, MIL blood levels at the end of treatment were similar in cured and relapsed patients. Conclusions. Relapse in one-fifth of the MIL-treated patients observed in our study is an alarming signal for the VL elimination campaign, urging for further review and cohort monitoring.

Recent developments in drug discovery for leishmaniasis and human African trypanosomiasis.

Abstract: Leishmaniasis is a parasitic disease that presents four main clinical syndromes: cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), visceral leishmaniasis/kala azar (VL), and post kala azar dermal leishmaniasis (PKDL). Causative Leishmania are protozoan parasites that are transmitted among mammalian hosts by phlebotomine sandflies. In mammalian hosts, parasite cells proliferate inside the host phagocytic cells as round amastigotes. Infection of sandflies with Leishmania occurs during insect feeding on infected mammalian hosts. After introduction into the insect gut together with the blood meal, Leishmania amastigotes transform into elongated flagellated promastigotes that propagate in the insect gut. A new round of infection is initiated after the infected sandfly takes a blood meal from a naive mammalian host and introduces Leishmania parasites into the bite wound in the host dermis (Scheme 1). More than 20 different Leishmania species have been found to cause human leishmaniasis (Table 1). Leishmaniasis is endemic in 98 countries and is closely associated with poverty. More than a million new cases are reported per year and 350 million people are at risk of contracting the infection. For the most severe form of leishmaniasis, VL, ∼300 000 new cases are estimated to occur annually resulting in ∼40 000 deaths. Approximately 90% of all VL cases occur in 3 endemic foci: 1. India, Bangladesh, and Nepal; 2. East Africa; and 3. Brazil. In spite of the high prevalence, currently available treatments for leishmaniasis are inadequate. Pentavalent antimonials, the standard treatment for leishmaniasis for many decades, are not efficacious in Bihar (∼60% of VL cases worldwide) any longer due to widespread resistance to the drug in this region. Several new VL treatments have emerged during the past 10–15 years, but each has serious shortcomings (summarized in Table 2). These include paromomycin (injectable, long treatment, region-dependent efficacy), miltefosine (cost, teratogenicity, long treatment), and liposomal amphotericin B (cost, hospitalization, region-dependent efficacy). An additional challenge is represented by patients with HIV/VL coinfections who are more difficult to cure (lower initial and final cure rates), have greater susceptibility to drug toxicity, and have higher rates of death and relapse. Due to the limitations of the existing treatments, better drugs are urgently needed. Ideally, new VL drugs would be efficacious across all endemic regions, would affect cure in ≤10 days, and would cost <$10 per course (for a complete target product profile for new VL drugs, which was formulated by DNDi, see Table 4).1 Here we describe the disease history and parasite biology followed by a summary of the currently available treatments and, finally, review reports of novel small molecules with antileishmanial activity.