Qualification: 
MD, MBBS
vanilkumar@aims.amrita.edu

Dr. Anil Kumar V. currently serves as Professor at the Department of Microbiology, School of Medicine, Kochi.

Publications

Publication Type: Journal Article

Year of Publication Publication Type Title

2018

Journal Article

S. C. Mellinghoff, Hoenigl, M., Koehler, P., Dr. Anil Kumar V., Lagrou, K., Lass-Flörl, C., Meis, J. F., Menon, V., Rautemaa-Richardson, R., and Cornely, O. A., “EQUAL Candida Score: An ECMM score derived from current guidelines to measure QUAlity of Clinical Candidaemia Management.”, Mycoses, vol. 61, no. 5, pp. 326-330, 2018.[Abstract]


Candida species frequently cause blood stream infections and are reported to be the third to tenth most commonly isolated pathogens. Guidelines and standardised treatment algorithms provided by professional organisations aim to facilitate decision-making regarding diagnosis, management and treatment of candidaemia. In routine clinical practise, however, it may be challenging to comply with these guidelines. The reasons include lack of familiarity or feasibility to adherence, but also their length and complexity. There is no tool to measure guideline adherence currently. To provide such a tool, we reviewed the current guidelines provided by the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) and by the Infectious Diseases Society of America (IDSA), and selected the strongest recommendations for management quality as the bases for our scoring tool. Factors incorporated were diagnostic (blood cultures, echocardiography, ophthalmoscopy, species identification) and follow-up procedures (repeat blood cultures until negative result) as well as key treatment parameters (echinocandin treatment, step down to fluconazole depending on susceptibility result, CVC removal). The EQUAL Candida Score weighs and aggregates factors recommended for the ideal management of candidaemia and provides a tool for antifungal stewardship as well as for measuring guideline adherence.

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2018

Journal Article

A. Singh, Healey, K. R., Yadav, P., Upadhyaya, G., Sachdeva, N., Sarma, S., Dr. Anil Kumar V., Tarai, B., Perlin, D. S., and Chowdhary, A., “Absence of Azole or Echinocandin Resistance in Candida glabrata Isolates in India despite Background Prevalence of Strains with Defects in the DNA Mismatch Repair Pathway.”, Antimicrob Agents Chemother, vol. 62, no. 6, 2018.[Abstract]


infections are increasing worldwide and exhibit greater rates of antifungal resistance than those with other species. DNA mismatch repair (MMR) gene deletions, such as , in resulting in a mutator phenotype have recently been reported to facilitate rapid acquisition of antifungal resistance. This study determined the antifungal susceptibility profiles of 210 isolates in 10 hospitals in India and investigated the impact of novel polymorphisms on mutation potential. No echinocandin- or azole-resistant strains and no mutations in hot spot regions were detected among the isolates, supporting our susceptibility testing results. CLSI antifungal susceptibility data showed that the MICs of anidulafungin (geometric mean [GM], 0.12 μg/ml) and micafungin (GM, 0.01 μg/ml) were lower and below the susceptibility breakpoint compared to that of caspofungin (CAS) (GM, 1.31 μg/ml). Interestingly, 69% of the strains sequenced contained six nonsynonymous mutations in , i.e., V239L and the novel mutations E459K, R847C, Q386K, T772S, and V239/D946E. Functional analysis of mutations revealed that 49% of the tested strains (40/81) contained a partial loss-of-function mutation. The novel substitution Q386K produced higher frequencies of CAS-resistant colonies upon expression in the mutant. However, expression of two other novel alleles, i.e., E459K or R847C, did not confer selection of resistant colonies, confirming that not all mutations in the MMR pathway affect its function or generate a phenotype of resistance to antifungal drugs. The lack of drug resistance prevented any correlations from being drawn with respect to genotype.

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2017

Journal Article

Dr. Anil Kumar V., Sachu, A., Mohan, K., Vinod, V., Dinesh, K. Radhakrish, and Karim, S., “Simple low cost differentiation of Candida auris from Candida haemulonii complex using CHROMagar Candida medium supplemented with Pal's medium”, Revista Iberoamericana de Micologia, 2017.[Abstract]


Background: Candida auris is unique due to its multidrug resistance and misidentification as Candida haemulonii by commercial systems. Its correct identification is important to avoid inappropriate treatments. Aims: To develop a cheap method for differentiating C. auris from isolates identified as C. haemulonii by VITEK2. Methods: Fifteen C. auris isolates, six isolates each of C. haemulonii and Candida duobushaemulonii, and one isolate of Candida haemulonii var. vulnera were tested using CHROMagar Candida medium supplemented with Pal's agar for better differentiation. Results: On CHROMagar Candida medium supplemented with Pal's agar all C. auris strains showed confluent growth of white to cream colored smooth colonies at 37. °C and 42. °C after 24 and 48. h incubation and did not produce pseudohyphae. The isolates of the C. haemulonii complex, on the contrary, showed poor growth of smooth, light-pink colonies at 24. h while at 48. h the growth was semiconfluent with the production of pseudohyphae. C. haemulonii complex failed to grow at 42. °C. Conclusions: We report a rapid and cheap method using CHROMagar Candida medium supplemented with Pal's agar for differentiating C. auris from isolates identified as C. haemulonii by VITEK2. © 2017 Asociación Española de Micología.

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2017

Journal Article

S. Vijayrajratnam, Pushkaran, A. Choorakott, Balakrishnan, A., Dr. Anil Kumar V., Dr. Raja Biswas, and Dr. Gopi Mohan C., “Understanding the molecular differential recognition of muramyl peptide ligands by LRR domains of human NOD receptors”, Biochem J, vol. 474, no. 16, pp. 2691-2711, 2017.[Abstract]


Human nucleotide-binding oligomerization domain proteins, hNOD1 and hNOD2, are host intracellular receptors with C-terminal leucine-rich repeat (LRR) domains, which recognize specific bacterial peptidoglycan (PG) fragments as their ligands. The specificity of this recognition is dependent on the third amino acid of the stem peptide of the PG ligand, which is usually meso-diaminopimelic acid (mesoDAP) or l-lysine (l-Lys). Since the LRR domains of hNOD receptors had been experimentally shown to confer the PG ligand-sensing specificity, we developed three-dimensional structures of hNOD1-LRR and the hNOD2-LRR to understand the mechanism of differential recognition of muramyl peptide ligands by hNOD receptors. The hNOD1-LRR and hNOD2-LRR receptor models exhibited right-handed curved solenoid shape. The hot-spot residues experimentally proved to be critical for ligand recognition were located in the concavity of the NOD-LRR and formed the recognition site. Our molecular docking analyses and molecular electrostatic potential mapping studies explain the activation of hNOD-LRRs, in response to effective molecular interactions of PG ligands at the recognition site; and conversely, the inability of certain PG ligands to activate hNOD-LRRs, by deviations from the recognition site. Based on molecular docking studies using PG ligands, we propose few residues - G825, D826 and N850 in hNOD1-LRR and L904, G905, W931, L932 and S933 in hNOD2-LRR, evolutionarily conserved across different host species, which may play a major role in ligand recognition. Thus, our integrated experimental and computational approach elucidates the molecular basis underlying the differential recognition of PG ligands by hNOD receptors.

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2016

Journal Article

S. Va Nair, Baranwal, Ga, Chatterjee, Ma, Sachu, Ac, Dr. Anil Kumar V., Bose, C., Dr. Asoke Banerji, and Dr. Raja Biswas, “Antimicrobial activity of plumbagin, a naturally occurring naphthoquinone from Plumbago rosea, against Staphylococcus aureus and Candida albicans”, International Journal of Medical Microbiology, vol. 306, pp. 237-248, 2016.[Abstract]


Candida albicans and Staphylococcus aureus are opportunistic pathogens. Despite causing a number of independent infections, both pathogens can co-infect to cause urinary tract infections, skin infections, biofilm associated infections, sepsis and pneumonia. Infections of these two pathogens especially their biofilm associated infections are often difficult to treat using currently available anti-bacterial and anti-fungal agents. In order to identify a common anti-microbial agent which could confer a broad range of protection against their infections, we screened several phytochemicals and identified plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), a phytochemical from Plumbago species as a potent antimicrobial agent against S. aureus and C. albicans, with a minimum inhibitory concentration of 5 μg/ml. Antimicrobial activity of plumbagin was validated using an ex-vivo porcine skin model. For better understanding of the antimicrobial activity of plumbagin, a Drosophila melanogaster infection model was used, where D. melanogaster was infected using S. aureus and C. albicans, or with both organisms. The fly's survival rate was dramatically increased when infected flies were treated using plumbagin. Further, plumbagin was effective in preventing and dispersing catheter associated biofilms formed by these pathogens. The overall results of this work provides evidence that plumbagin, possesses an excellent antimicrobial activity which should be explored further for the treatment of S. aureus and C. albicans infections. © 2016 Elsevier GmbH.

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2016

Journal Article

S. Vijayrajratnam, Pushkaran, A. Choorakott, Balakrishnan, A., Dr. Anil Kumar V., Dr. Raja Biswas, and Dr. Gopi Mohan C., “Bacterial peptidoglycan with amidated meso-diaminopimelic acid evades NOD1 recognition: an insight into NOD1 structure-recognition.”, Biochem J, vol. 473, no. 24, pp. 4573-4592, 2016.[Abstract]


Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) is an intracellular pattern recognition receptor that recognizes bacterial peptidoglycan (PG) containing meso-diaminopimelic acid (mesoDAP) and activates the innate immune system. Interestingly, a few pathogenic and commensal bacteria modify their PG stem peptide by amidation of mesoDAP (mesoDAPNH2). In the present study, NOD1 stimulation assays were performed using bacterial PG containing mesoDAP (PGDAP) and mesoDAPNH2 (PGDAPNH2) to understand the differences in their biomolecular recognition mechanism. PGDAP was effectively recognized, whereas PGDAPNH2 showed reduced recognition by the NOD1 receptor. Restimulation of the NOD1 receptor, which was initially stimulated with PGDAP using PGDAPNH2, did not show any further NOD1 activation levels than with PGDAP alone. But the NOD1 receptor initially stimulated with PGDAPNH2 responded effectively to restimulation with PGDAP The biomolecular structure-recognition relationship of the ligand-sensing leucine-rich repeat (LRR) domain of human NOD1 (NOD1-LRR) with PGDAP and PGDAPNH2 was studied by different computational techniques to further understand the molecular basis of our experimental observations. The d-Glu-mesoDAP motif of GMTPDAP, which is the minimum essential motif for NOD1 activation, was found involved in specific interactions at the recognition site, but the interactions of the corresponding d-Glu-mesoDAP motif of PGDAPNH2 occur away from the recognition site of the NOD1 receptor. Hot-spot residues identified for effective PG recognition by NOD1-LRR include W820, G821, D826 and N850, which are evolutionarily conserved across different host species. These integrated results thus successfully provided the atomic level and biochemical insights on how PGs containing mesoDAPNH2 evade NOD1-LRR receptor recognition.

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2015

Journal Article

Dr. Anil Kumar V. and S. Khan, “Defining Multidrug Resistance in Gram-negative Bacilli”, Indian Journal of Medical Research, vol. 141, pp. 491-493, 2015.

2015

Journal Article

D. Mathai, Dr. Anil Kumar V., Paul, B., Sugumar, M., John, K. R., Manoharan, A., and Kesavan, L. M., “Fecal carriage rates of extended-spectrum β-lactamase-producing escherichia coli among antibiotic naive healthy human volunteers”, Microbial Drug Resistance, vol. 21, pp. 59-64, 2015.[Abstract]


Introduction: Higher prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli fecal carriage has been reported in the nosocomial setting than in the community. We tried to determine the fecal carriage of ESBL-producing E. coli among healthy volunteers in a relatively isolated community. Materials and Methods: This study was conducted on 115 healthy adult volunteers from whom one fecal sample was collected and was plated on selective media. Each morphotypes were identified, characterized, and ESBL phenotype was confirmed by double-disk potentiation method. Molecular characterization of ESBL gene was done using multiplex polymerase chain reaction and pulse-field gel electrophoresis (PFGE) was done to identify their clonal relation. Results: ESBL-producing E. coli had a prevalence of 19% (22/115) among the healthy volunteers in the community. CTX-M was the predominant type, showed a presence 95.5% (21/22), TEM 63%, SHV 9%, and both TEM and CTX-M were present in 63.6% (14/22), all three present in 4.5% (1/22). The lineage using PFGE showed a single clone in 17 isolates. Seven isolates were type A (all TEM & CTX-M), six were type A1 (all TEM & CTX-M except 2), four were type A2 (all CTX-M), and three belonged to types B, C, and D respectively Conclusion: High prevalence rate of 19% in the community indicated by this study implies the possibility of sustained ESBL carriage even among isolated population, which could serve as a reservoir for enriching the ESBL pool in the hospital. Clonal relations also indicate a possible epidemiological source that needs to be evaluated. © Copyright 2015, Mary Ann Liebert, Inc. 2015.

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2014

Journal Article

Dr. Anil Kumar V., “Susceptibility testing of staphylococcus aureus”, Indian Journal of Medical Research, vol. 139, p. 646, 2014.

2012

Journal Article

Dr. Anil Kumar V., “Recent updates on Methicillin resistant Staphylococcus aureus typing”, Indian Journal of Medical Microbiology, vol. 30, p. 374, 2012.

2012

Journal Article

Dr. Anil Kumar V., “Article published elsewhere as abstract”, Indian Journal of Medical Microbiology, vol. 30, pp. 253-254, 2012.

207
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AMRITA
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