Qualification: 
Ph.D
Email: 
lalithabiswas@aims.amrita.edu

Dr. Lalitha Biswas joined as Assistant Professor at Amrita Institute of Medical Sciences in Jan 2010. She obtained her Ph.D from the University of Tuebingen, Germany. Her postdoctoral training was at University of Tuebingen, Germany and Purdue University, Indiana, USA. She was a member of the Graduate College Infection Biology (GKI-685), German Research Foundation and Sonder Forshungs Bereich (SFB). A couple of research projects on which she is currently working on is concentrated on molecular biology and Infection biology which is funded by DST and ICMR.

She adds to her achievements the author and co - author of nearly 11 publications in various reputed journals like journal of immunology, journal of Bacteriology etc. She qualified CSIR - NET in the year 2000. Apart from these she owned the DFG fellowship from 2002 - 2006 and also received the fellowship from German Sonder Forshungs Bereich for the year 2007 - 2009.

Currently, Dr. Biswas also heads the Molecular biology diagnostic laboratory, which provides diagnostic services under various categories such as histocompatability & immunogenetics, gene testing, pharmacogenomics, cancer genetics and molecular basis of infectious diseases.

Publications

Publication Type: Journal Article

Year of Publication Title

2021

Alka Suresh, Parasmal Suresh, Dr. Raja Biswas, Anupama Rajanbabu, Sarala Sreedhar, and Dr. Lalitha Biswas, “Prevalence of high-risk HPV and its genotypes-Implications in the choice of prophylactic HPV vaccine.”, J Med Virol, vol. 93, no. 8, pp. 5188-5192, 2021.[Abstract]


The prevalence of human papillomavirus (HPV) types varies geographically between various countries and different parts of the same country. The efficacy of the HPV vaccines is dependent on the prevalent HPV types. Here, we have studied the prevalence of high-risk HPV (hrHPV) and its genotypes in women in our population. Cervical samples of 2443 women were screened for the presence of hrHPV using the careHPV system. To determine the HPV genotypes, viral DNA was isolated from the hrHPV-positive samples, nested PCR was used to amplify the L1 hypervariable region, and was subjected to Sanger sequencing. The prevalence of hrHPV was found to be 2%. HPV16 (52%), HPV33 (40%), HPV18 (4%), HPV31 (2%), and HPV66 (2%) genotypes were found in this study. In Kerala, HPV16 and HPV33 genotypes were found to be significantly higher compared with the other HPV types detected. As the bivalent (Cervarix) and quadrivalent (Gardasil-4) vaccines offer limited cross-protection against HPV33, nonavalent (Gardasil 9) vaccine would be more effective in preventing cervical carcinoma in Kerala.

More »»

2021

Dr. Anil Kumar V., Ani Sreedhar, Dr. Lalitha Biswas, Sarga Prabhat, Parasmal Suresh, Asokan, A., Rita Mary Tomy, Vivek Vinod, Bindu Lakshmanan, Ajit Nambiar, and Dr. Raja Biswas, “Candidatus Dirofilaria Hongkongensis Infections in Humans During 2005 to 2020, in Kerala, India.”, American Journal of Tropical Medicine and Hygiene, vol. 104, pp. 2046-2049., 2021.[Abstract]


We tried to determine the epidemiology and species of human dirofilariasis observed at two tertiary care hospitals in Kerala. We searched the hospital database to identify cases of dirofilariosis from January 2005 to March 2020. Along with human isolates, one dog Dirofilaria isolate was also subjected to PCR and sequencing of pan filarial primers cytochrome oxidase subunits 1 and 12S rDNA. We documented 78 cases of human dirofilariosis. The orbit, eyelid, and conjunctiva were the most commonly affected sites. Molecular characterization identified one dog and five human isolates as Candidatus Dirofilaria Hongkongensis. A rare case of subconjunctival infestation by B. malayi was also documented. Human dirofilariosis is a public health problem in the state of Kerala in India, and it is mostly caused by Candidatus Dirofilaria Hongkongensis. We propose that all diroifilaria isolates are subjected to sequencing for identification.

More »»

2021

Navia Vinoy, Neethu Sheeja, Suresh Kumar, and Dr. Lalitha Biswas, “Class II HLA (DRB1, & DQB1) alleles and IL7R (rs6897932) variants and the risk for Multiple Sclerosis in Kerala, India.”, Multiple Sclerosis and Related Disorders, vol. 50, p. 102848, 2021.[Abstract]


BACKGROUND: Different human leukocyte antigen (HLA) variants are known to modulate the risk of multiple sclerosis. The main objective of this study was to identify HLA-DRB1 and HLA-DQB1 alleles and Non -HLA gene IL7R (rs6897932) variants associated with MS.

METHODS: Patients attending the MS clinic, diagnosed with Multiple Sclerosis as per Mc Donald diagnostic criteria were the subjects in the study. The association of the highly polymorphic HLA-DRB1 and HLA-DQB1 loci was determined by high resolution tissue typing and the genotyping of the IL7R (rs6897932) variants was performed by Sanger sequencing in MS patients (n = 81) and healthy individuals (n = 82).

RESULTS: HLA-DRB1*15:01/15:02 alleles (OR = 3.65; p< 0.0001) and HLA-DQB1*06:02 (OR=4.19, p<0.0001) were found to be positively associated while HLA-DRB1*14:04:01 (OR = 0.21; p = 0.0009) was found to be negatively associated with MS. The most significant predisposing HLA haplotype was found to be DRB1*15:01-DQB1*06:02 (OR=5.69, p<0.0001). Univariate analysis of IL7R SNP (rs6897932) showed no significant association with MS in our population whereas analysis of HLA-DRB1 alleles and IL7R (rs6897932) genotypes showed significant association between the HLA-DRB1*15:01/15:02 and the IL7R (rs6897932) CC genotype (OR = 3.58, p = 0.0002).

CONCLUSION: HLA-DRB1*15:01, 15:02 and DQB1*06:02 are the predisposing alleles while HLA-DRB1*14:04 is the protective allele for MS in our population.

More »»

2021

Dr. Anil Kumar V., Radhamany Kunjukutty, Ameena Thaha, Saranya Srikumar, Haritha Madhusoodanan, Sachin David, Dr. Lalitha Biswas, and Dipu Sathyapalan, “Universal screening for SARS-CoV-2 in pregnant women using a combination of antigen and RT-PCR testing.”, Infezioni in Medicina, vol. 29, no. 2, pp. 294-296, 2021.

2021

Deepa Nair, Nandita Shashindran, Anil kumar, Vivek Vinodh, Dr. Lalitha Biswas, and Dr. Raja Biswas, “Comparison of Phenotypic MRSA Detection Methods with PCR for Gene in the Background of Emergence of Oxacillin-Susceptible MRSA.”, Microbial Drug Resistance, vol. 27, no. 9, pp. 1190-1194, 2021.[Abstract]


Phenotypic methods for detection of methicillin resistance in (MRSA) can be inaccurate due to heterogeneous expression of resistance and due to environmental factors that influence the expression of resistance. This study aims to compare various phenotypic methods of detection of methicillin resistance with polymerase chain reaction (PCR) for gene and to detect the presence of oxacillin-susceptible MRSA (OS-MRSA). A total of 150 isolates were tested using cefoxitin disk diffusion, oxacillin salt agar (OSA), latex agglutination test for penicillin binding protein 2a antigen, chromogenic MRSA ID agar, and PCR. Using PCR as the gold standard, 91 (60.66%) of 150 clinical strains were identified as MRSA. Three oxacillin-susceptible (minimum inhibitory concentration ≤2 μg/mL) -positive isolates were classified as OS-MRSA. Among the different phenotypic MRSA detection methods studied, latex agglutination had the highest sensitivity and specificity (98.9% and 98.3%), followed by cefoxitin disk diffusion (95.6% and 98.3%), MRSA ID (97.8% and 83.05%), and OSA (86.81% and 94.92%). The sensitivity of cefoxitin disk diffusion method may be reduced in areas with a high prevalence of OS-MRSA where a combination of cefoxitin disk diffusion test with MRSA ID agar or latex agglutination is recommended.

More »»

2021

M. K. Suresh, Vasudevan, A. K., Dr. Lalitha Biswas, and Dr. Raja Biswas, “Protective efficacy of Alum adjuvanted Amidase protein vaccine against Staphylococcus aureus infection in multiple mouse models.”, Journal of Applied Microbiology (Article in Press), 2021.[Abstract]


AIMS: Staphylococcus aureus is an opportunistic pathogen of humans. No commercial vaccine is available to combat S. aureus infections. In this study, we have investigated the protective immune response generated by S. aureus non-covalently associated cell wall surface protein N-acetylmuramoyl-L-alanine amidase (AM) in combination with Alum (Al) and heat-killed S. aureus (hkSA) using murine models.

METHODS AND RESULTS: BALB/c mice were immunized with increasing concentrations of AM antigen or hkSA to determine their optimum concentration for vaccination. Fifty micrograms of AM and hkSA each were found to generate maximum anti-AM IgG antibody production. BALB/c mice were immunized next with 50 µg of AM, 50 µg of hKSA and 1 mg Al vaccine formulation. Vaccine efficacy was validated by challenging immunized BALB/c mice with S. aureus Newman and three clinical methicillin-resistant S. aureus strains. AM-hkSA-Al-immunized mice generated high anti-AM IgG antibody response with IgG1 and IgG2b as the predominant immunoglobulin subtypes. Increased survival (60%-90%) with decreased clinical disease symptoms was observed in the vaccinated BALB/c mice group. A significantly lower bacterial load and decreased kidney abscess formation was observed following the challenge with S. aureus in the vaccinated BALB/c mice group. Furthermore, the efficacy of AM-hkSA-Al vaccine was also validated using C57 BL/6 and Swiss albino mice.

CONCLUSIONS: Using murine infection models, we have demonstrated that AM-hkSA-Al vaccine would be effective in preventing S. aureus infections.

SIGNIFICANCE AND IMPACT OF STUDY: AM-hkSA-Al vaccine elicited strong immune response and may be considered for future vaccine design against S. aureus infections.

More »»

2021

Ayswarya Kannan, Dr. Lalitha Biswas, Anil Kumar, Jessy Kurian, Anjaly S. Nair, Parasmal Suresh, Shine Sadasivan, and Dr. Raja Biswas, “Improving Diagnosis of Hepatitis C Virus Infection Using Hepatitis C Core Antigen Testing in a Resource-Poor Setting.”, Rev Soc Bras Med Trop, vol. 54, p. e02532020, 2021.[Abstract]


INTRODUCTION: We compared the hepatitis C virus (HCV) core antigen test with the HCV RNA assay to confirm anti-HCV results to determine whether the HCV core antigen test could be used as an alternative confirmatory test to the HCV RNA test.

METHODS: Sera from 156 patients were analyzed for anti-HCV and HCV core antigen using a chemiluminescent microparticle immunoassay (Architect i2000SR) and for HCV RNA using the artus HCV RG RT-PCR Kit (QIAGEN) in a Rotor-Gene Q instrument.

RESULTS: The diagnostic sensitivity, specificity, and positive and negative predictive values of the HCV core antigen assay compared to the HCV RNA test were 77.35%, 100%, 100%, and 89.38%, respectively. HCV core antigen levels showed a good correlation with those from HCV RNA quantification (r =0.872). However, 13 samples with a viral load of less than 4000 IU/mL were negative in the HCV core antigen assay. All gray-zone reactive samples were also RNA positive and were positive on repeat testing.

CONCLUSIONS: The Architect HCV core antigen assay is highly specific and has an excellent positive predictive value. At the present level of sensitivity (77%), the study is still relevant in a low-income setting in which most of the HCV-positive patients would go undiagnosed, since HCV RNA testing is not available and/or not affordable. HCV core antigen testing can also help determine the true burden of infection in a population, considering the fact that almost 50% of the anti-HCV positive cases are negative for HCV RNA.

More »»

2021

Dr. Anil Kumar V., Aswin Prabhakaran, Sanju Sherji, Dr. Lalitha Biswas, Arya Ramachandran, Mohan Abraham, and Dr. Raja Biswas, “Dirofilarial adult worms can also dance.”, Clinical Microbiology and Infection, vol. 27, pp. 1118-1119., 2021.[Abstract]


A boy in his teens on long-term treatment with mycophenolate mofetil and steroids presented with a nodular swelling on the volar aspect of the right forearm. During the previous 2 months, he had experienced creeping eruptions of the right arm. The patient had never travelled outside India. Physical examination found a tender, well-defined 1 × 1-cm, mobile swelling in the subcutaneous plane with fixing of the skin. Ultrasound scan of the swelling revealed a 1.3 × 0.9 cm hyperechoic lesion suggestive of a live worm ( Fig. 1, and see Supplementary material, video S1). Laboratory investigations showed a normal blood leucocyte count without eosinophilia. The excised cystic lesion on sectioning revealed a white thread-like, live worm in a coiled state (see Supplementary material, videos S2, S3). Scanning electron microscopy of the worm surface showed longitudinal ridges and transverse striations ( Fig. 2A,B) ruling out Dirofilaria immitis. The worm was subjected to multiplex PCR, which identified it as Dirofilaria repens; however, sequencing of the cyclo-oxygenase type 1 gene identified it as Candidatus Dirofilaria hongkongensis.

More »»

2021

Jayakumar Jayashree, V.A. Kumar, Dr. Lalitha Biswas, and Dr. Raja Biswas, “Therapeutic applications of lysostaphin against Staphylococcus aureus”, Journal of Applied Microbiology, vol. n/a, 2021.[Abstract]


Staphylococcus aureus, an opportunistic pathogen, causes diverse community and nosocomial-acquired human infections, including folliculitis, impetigo, sepsis, septic arthritis, endocarditis, osteomyelitis, implant-associated biofilm infections and contagious mastitis in cattle. In recent days, both methicillin-sensitive and methicillin-resistant S. aureus infections have increased. Highly effective anti-staphylococcal agents are urgently required. Lysostaphin is a 27 kDa zinc metallo antimicrobial lytic enzyme that is produced by Staphylococcus simulans biovar staphylolyticus and was first discovered in the 1960s. Lysostaphin is highly active against S. aureus strains irrespective of their drug-resistant patterns with a minimum inhibitory concentration of ranges between 0·001 and 0·064 μg ml−1. Lysostaphin has activity against both dividing and non-dividing S. aureus cells; and can seep through the extracellular matrix to kill the biofilm embedded S. aureus. In spite of having excellent anti-staphylococcal activity, its clinical application is hindered because of its immunogenicity and reduced bio-availability. Extensive research with lysostaphin lead to the development of several engineered lysostaphin derivatives with reduced immunogenicity and increased serum half-life. Therapeutic efficacy of both native and engineered lysostaphin derivatives was studied by several research groups. This review provides an overview of the therapeutic applications of native and engineered lysostaphin derivatives developed to eradicate S. aureus infections.

More »»

2020

A. A., Sidharthan, N., Vidyadharan, G., Kurian, J., and Dr. Lalitha Biswas, “Mutation Profile of JAK2, EPOR and CALR Genes in Polycythemia Patients”, Blood Cells, Molecules, and Diseases, vol. 82, p. 102414, 2020.

2017

P. S. Panicker, Melge, A. R., Dr. Lalitha Biswas, Keechilat, P., and Dr. Gopi Mohan C., “Epidermal Growth Factor Receptor (EGFR) Structure-based Bioactive Pharmacophore Models for Identifying Next-generation Inhibitors Against Clinically relevant EGFR Mutations”, Chemical Biology & Drug Design, vol. 90, pp. 629-636, 2017.[Abstract]


Present work elucidates identification of next generation inhibitors for clinically relevant mutations of epidermal growth factor receptor (EGFR) using structure-based bioactive pharmacophore modeling followed by virtual screening (VS) techniques. Three-dimensional (3D) pharmacophore models of EGFR and its different mutants were generated. This includes seven 3D pharmacophoric points with three different chemical features (descriptors), that is, one hydrogen bond donor, three hydrogen bond acceptors and three aromatic rings. Pharmacophore models were validated using decoy dataset, Receiver operating characteristic plot, and external dataset compounds. The robust, bioactive 3D e-pharmacophore models were then used for VS of four different small compound databases: FDA approved, investigational, anticancer, and bioactive compounds collections of Selleck Chemicals. CUDC101 a multitargeted kinase inhibitor showed highest binding free energy and 3D pharmacophore fit value than the well known EGFR inhibitors, Gefitinib and Erlotinib. Further, we obtained ML167 as the second best hit on VS from bioactive database showing high binding energy and pharmacophore fit value with respect to EGFR receptor and its mutants. Optimistically, presented drug discovery based on the computational study serves as a foundation in identifying and designing of more potent EGFR next-generation kinase inhibitors and warrants further experimental studies to fight against lung cancer.

More »»

2017

Dr. Lalitha Biswas, CG, N., M, B., Pradeep Jacob, Riju R. Menon, AK, R., and K, N., “Lack of Association of B-type Raf Kinase V600E Mutation with High-risk Tumor Features and Adverse Outcome in Conventional and Follicular Variants of Papillary Thyroid Carcinoma”, Indian Journal of Endocrinol Metab, vol. 21, no. 2, pp. 329-333, 2017.[Abstract]


INTRODUCTION:
Somatic B-type Raf kinase (BRAF) V600E mutation in exon 15 was frequently found in high frequencies associated with papillary thyroid cancer (PTC). The phenotype of these cancers expressed aggressive clinical and pathological features. The present study aimed to assess the prevalence of BRAF V600E mutation among conventional and follicular variants of PTC and its association with aggressive tumor factors and outcome.

STUDY DESIGN:
Patients who were operated and received further treatment for PTC during 2012 were included in the study. BRAF V600E mutation analysis was done by extracting genomic DNA from tumor tissue.

RESULTS:
Of the 59 patients included in the study, 51% harbored BRAF V600E mutation, but the mutation status was not associated with aggressive tumor factors and adverse outcome.

CONCLUSION:
BRAF V600E mutation was not significant predictor of aggressive tumor behavior in conventional and follicular variants of PTC.

More »»

2017

G. Baranwal, Mohammad, M., Jarneborn, A., Reddy, B. Raghunath, Golla, A., Chakravarty, S., Dr. Lalitha Biswas, Götz, F., Shankarappa, S., Jin, T., and Raja Biswas, “Impact of Cell Wall Peptidoglycan O-acetylation on the Pathogenesis of Staphylococcus Aureus in Septic Arthritis”, International Journal of Medical Microbiology, vol. 307, pp. 388 - 397, 2017.[Abstract]


Staphylococcus aureus (S. aureus) is one of the most common pathogen causing septic arthritis. To colonize the joints and establish septic arthritis this bacterium needs to resist the host innate immune responses. Lysozyme secreted by neutrophils and macrophages is an important defense protein present in the joint synovial fluids. S. aureus is known to be resistant to lysozyme due to its peptidoglycan modification by O-acetylation of N-acetyl muramic acid. In this study we have investigated the role of O-acetylated peptidoglycan in septic arthritis. Using mouse models for both local and hematogenous S. aureus arthritis we compared the onset and progress of the disease induced by O-acetyl transferase mutant and the parenteral wild type SA113 strain. The disease progression was assessed by observing the clinical parameters including body weight, arthritis, and functionality of the affected limbs. Further X-ray and histopathological examinations were performed to monitor the synovitis and bone damage. In local S. aureus arthritis model, mice inoculated with the ΔoatA strain developed milder disease (in terms of knee swelling, motor and movement functionality) compared to mice inoculated with the wild type SA113 strain. X-ray and histopathological data revealed that ΔoatA infected mice knee joints had significantly lesser joint destruction, which was accompanied by reduced bacterial load in knee joints. Similarly, in hematogenous S. aureus arthritis model, ΔoatA mutant strain induced significantly less severe clinical septic arthritis compared to its parental strain, which is in accordance with radiological findings. Our data indicate that peptidoglycan O-acetylation plays an important role in S. aureus mediated septic arthritis.

More »»

2017

Dr. Lalitha Biswas, S, I., M, S., P, K., J, M., R, J., R, R., A, W., ,, SM, C. Mali, V, V., A, C., S, D., A, O., G, K., R, N., A, M., Z, P., and M, E., “First Two Bilateral Hand Transplantations in India (Part 4): Immediate Post-operative Care, Immunosuppression Protocol and Monitoring”, Indian J Plast Surg, vol. 50, no. 2, pp. 168-172, 2017.[Abstract]


Being able to counter immune-mediated rejection has for decades been the single largest obstacle for the progress of vascular composite allotransplantation (VCA). The human immune system performs the key role of differentiating the 'self ' from the 'non-self '. This, although is quintessential to eliminate or resist infections, also resists the acceptance of an allograft which it promptly recognises as 'non-self'.

More »»

2016

C. S. Keechilot, Shenoy, V., A. Kumar, Dr. Lalitha Biswas, Vijayrajratnam, S., Dinesh, K., and Dr. Prem Kumar Nair, “Detection of Occult Hepatitis B and Window Period Infection Among Blood Donors by Individual donation Nucleic Acid Testing in a Tertiary Care Center in South India”, Pathogens and Global Health, pp. 1-5, 2016.[Abstract]


With the introduction of highly sensitive hepatitis B surface antigen immunoassay, transfusion associated HBV infection have reduced drastically but they still tend to occur due to blood donors with occult hepatitis B infection (OBI) and window period (WP) infection. Sera from, 24338 healthy voluntary blood donors were screened for HBsAg, HIV and HCV antibody using Vitros Enhanced Chemiluminescent Immunoassay. The median age of the donor population was 30 (range 18–54) with male preponderance (98%). All serologically negative samples were screened by nucleic acid testing (NAT) for viral DNA and RNA. NAT-positive samples were subjected to discriminatory NAT for HBV, HCV, and HIV and all samples positive for HBV DNA were tested for anti-HBc, anti-HBs, HBeAg. Viral load was determined using artus HBV RG PCR Kit. Of the 24,338 donors screened, 99.81% (24292/24338) were HBsAg negative of which NAT was positive for HBV DNA in 0.0205% (5/24292) donors. Four NAT positive donors had viral load of &lt;200&nbsp;IU/ml making them true cases of OBI. One NAT positive donor was negative for all antibodies making it a case of WP infection. Among OBI donors, 75% (3/4) were immune and all were negative for HBeAg. Precise HBV viral load could not be determined in all (5/5) NAT positive donors due to viral loads below the detection limit of the artus HBV RG PCR Kit. The overall incidence of OBI and WP infections was found to be low at 1 in 6503 and 1 in 24214 donations, respectively. More studies are needed to determine the actual burden of WP infections in Indian blood donors.

More »»
PDF icondetection-occult-hepatitis-b-window-period-infection.pdf

2015

N. Nair, Vinod, V., Suresh, M. K., Vijayrajratnam, S., Dr. Lalitha Biswas, Peethambaran, R., Vasudevan, A. K., and Dr. Raja Biswas, “Amidase, a Cell Wall Hydrolase, Elicits Protective Immunity Against Staphylococcus Aureus and S. Epidermidis”, International Journal of Biological Macromolecules, vol. 77, pp. 314-321, 2015.[Abstract]


The morbidity and the mortality associated with Staphylococcus aureus and S. epidermidis infections have greatly increased due to the rapid emergence of highly virulent and antibiotic resistant strains. Development of a vaccine-based therapy is greatly desired. However, no staphylococcal vaccine is available till date. In this study, we have identified Major amidase (Atl-AM) as a prime candidate for future vaccine design against these pathogens. Atl-AM is a multi-functional non-covalently cell wall associated protein which is involved in staphylococcal cell separation after cell division, host extracellular matrix adhesion and biofilm formation. Atl-AM is present on the surface of diverse S. aureus and S. epidermidis strains. When used in combination with Freund's adjuvant, Atl-AM generated a mixed Th1 and Th2 mediated immune response which is skewed more toward Th1; and showed increased production of opsonophagocytic IgG2a and IgG2b antibodies. Significant protective immune response was observed when vaccinated mice were challenged with S. aureus or S. epidermidis. Vaccination prevented the systemic dissemination of both organisms. Our results demonstrate the remarkable efficacy of Atl-AM as a vaccine candidate against both of these pathogens. © 2015 Elsevier B.V.

More »»

2014

N. Nair, Biswas, R., Götz, F., and Dr. Lalitha Biswas, “Impact of Staphylococcus aureus on Pathogenesis in Polymicrobial Infections”, Infection and Immunity, vol. 82, pp. 2162–2169, 2014.[Abstract]


Polymicrobial infections involving Staphylococcus aureus exhibit enhanced disease severity and morbidity. We reviewed the nature of polymicrobial interactions between S. aureus and other bacterial, fungal, and viral cocolonizers. Microbes that were frequently recovered from the infection site with S. aureus are Haemophilus influenzae, Enterococcus faecalis, Pseudomonas aeruginosa, Streptococcus pneumoniae, Corynebacterium sp., Lactobacillus sp., Candida albicans, and influenza virus. Detailed analyses of several in vitro and in vivo observations demonstrate that S. aureus exhibits cooperative relations with C. albicans, E. faecalis, H. influenzae, and influenza virus and competitive relations with P. aeruginosa, Streptococcus pneumoniae, Lactobacillus sp., and Corynebacterium sp. Interactions of both types influence changes in S. aureus that alter its characteristics in terms of colony formation, protein expression, pathogenicity, and antibiotic susceptibility.

More »»

2014

Anil Kumar, Sreehari, S., Velayudhan, K., Dr. Lalitha Biswas, Babu, R., Ahmed, S., Sharma, N., Kurupath, V. P., Jojo, A., Dinesh, K. R., Karim, S., and Biswas, R., “Autochthonous Blastomycosis of the Adrenal: First Case Report from Asia”, The American Journal of Tropical Medicine and Hygiene, vol. 90, 2014.

2013

Va Sukhithasri, Nisha, Na, Dr. Lalitha Biswas, Kumar, VbAnil, and Dr. Raja Biswas, “Innate immune recognition of microbial cell wall components and microbial strategies to evade such recognitions”, Microbiological Research, vol. 168, pp. 396-406, 2013.[Abstract]


The innate immune system constitutes the first line of defence against invading microbes. The basis of this defence resides in the recognition of defined structural motifs of the microbes called "Microbial associated molecular patterns" that are absent in the host. Cell wall, the outer layer of both bacterial and fungal cells, a unique structure that is absent in the host and is recognized by the germ line encoded host receptors. Nucleotide oligomerization domain proteins, peptidoglycan recognition proteins and C-type lectins are host receptors that are involved in the recognition of bacterial cell wall (usually called peptidoglycan), whereas fungal cell wall components (N- and O-linked mannans, β-glucans etc.) are recognized by host receptors like C-type lectins (Dectin-1, Dectin-2, mannose receptor, DC-SIGN), Toll like receptors-2 and -4 (TLR-2 and TLR-4). These recognitions lead to activation of a variety of host signaling cascades and ultimate production of anti-microbial compounds including phospholipase A2, antimicrobial peptides, lysozyme, reactive oxygen and nitrogen species. These molecules act in cohort against the invading microbes to eradicate infections. Additionally pathogen recognition leads to the production of cytokines, which further activate the adaptive immune system. Both pathogenic and commensal bacteria and fungus use numerous strategies to subvert the host defence. These strategies include bacterial peptidoglycan glycan backbone modifications by O-acetylation, N-deacetylation, N-glycolylation and stem peptide modifications by amidation of meso-Diaminopimelic acid; fungal cell wall modifications by shielding the β-glucan layer with mannoproteins and α-1,3 glucan. This review focuses on the recent advances in understanding the role of bacterial and fungal cell wall in their innate immune recognition and evasion strategies. © 2013 Elsevier GmbH.

More »»