1.Epitope variances demonstrated by Blastocystis sp. ST3 symptomatic and asymptomatic isolates
Sheela, D.S. ; Chandramathi, S. ; Suresh, K.
Tropical Biomedicine 2020;37(No.1):210-217
Blastocystis sp. is an enteric protozoan parasite of humans and many animals. Blastocystis sp. subtype 3 (ST3) proves to be the highest frequency case in most populations around the world and it is further distinguished into symptomatic and asymptomatic isolates based on the clinical symptoms exhibited by infected individuals. Phenotypic and genotypic studies implicate the distinctiveness of this parasite which may describe its pathogenesis. However, the antigenic distinctiveness which describes the antibody mediated cell lysis of this parasite has not been explored. This study was aimed to identify the cross-reactivity and cytotoxicity effect between three isolates of symptomatic and asymptomatic Blastocystis sp. ST3 respectively. Antigen specificity and diversity of this parasite was performed by coculturing sera (10-fold dilution) obtained from mice immunised with Blastocystis sp. symptomatic and asymptomatic antigens and the respective Blastocystis sp. ST3 live cells through complement dependant cell cytotoxicity (CDC) assay. The results obtained has shown that, the sera (at 10-fold diluted concentration) from symptomatic and asymptomatic solubilised antigen immunised mice were able to specifically lyse the respective live parasites with an average percentage of 82% and 86% respectively. There were almost 50% crossreactivity observed between the three isolates of Blastocystis sp. ST3 from symptomatic and asymptomatic group proving high antigen diversity or rather low antigen specificity within the same group. However, there was only 17% cross-reactivity observed between the mice sera and parasitic cells of different groups (symptomatic vs asymptomatic isolates) suggesting high specificity between these two groups. We, for the first time have proven that through CDC analysis there were epitopes dissimilarities between Blastocystis sp. ST3 symptomatic and asymptomatic isolates which may allow the parasite to set up diverse immune modulations such as imbalanced Th1/Th2 responses in an infected host.
2.Evaluation of bactericidal and virucidal activity of novel disinfectant Aaride AGT-1 compared to other commercially available disinfectants against hospital-acquired infections (HAIs)
Jindal, H.M. ; Chandramathi, S. ; Sekaran, S.D. ; Suresh, K.
Tropical Biomedicine 2020;37(No.3):626-636
Hand hygiene is the topmost crucial procedure to prevent hospital-acquired infections. Choosing an effective hand disinfectant is necessary in enforcing good hand hygiene practice especially in hospital settings. The aim of the study was to investigate the efficacy of Aaride AGT-1 as a hand disinfectant for the inhibition of pathogenic microorganisms’ transmission among both patients and personnel in the health care system compared to other commercially available disinfectants. In the present study, a new hand disinfectant Aaride AGT-1 was tested against several bacterial and viral pathogens to evaluate its antimicrobial activity profile. The results revealed that Aaride AGT-1 displayed the highest antibacterial activity against five pathogenic bacteria including MRSA when compared to other commercially available hand sanitizers. Aaride AGT-1 showed the lowest percentage needed to inhibit the growth of bacterial pathogens. In addition, results obtained from time killing assay revealed that Aaride AGT-1 demonstrated the best killing kinetics, by eradicating the bacterial cells rapidly within 0.5 min with 6 log reduction (>99.99% killing). Also, Aaride AGT1 was able to reduce 100% plaque formed by three viruses namely HSV-1, HSV-2 and EV-71. In conclusion, Aaride AGT-1 is capable of killing wide-spectrum of pathogens including bacteria and viruses compared to other common disinfectants used in hospital settings. Aaride AGT-1’s ability to kill both bacteria and viruses contributes as valuable addition to the hand disinfection portfolio.
3.Release of pro-inflammatory cytokines TNF-α, IFN-γ and IL-6 by Burkholderia pseudomallei- stimulated peripheral blood mononucleocytes of acute myeloid leukemia patients
Zulpa, A.K. ; Barathan, M. ; Iyadorai, T. ; Chandramathi, S. ; Vellasamy, K.M. ; Vadivelu, J. ; Gan, G.G. ; Anuar, N.A.
Tropical Biomedicine 2021;38(No.2):180-185
Acute myeloid leukemia (AML) is a malignant disease progressed from abnormal production of immature myeloid cells, which is often associated with concurrent infections after diagnosis. It was widely established that infections are the major contributors to mortality in this group due to the prevalency of neutropenia. Gram-negative Burkholderia pseudomallei is the causative agent of melioidosis. This disease had been reported in several neutropenic cancer patients undergoing chemotherapy resulting in severe clinical presentations and high mortalities which is in need of critical attention. Studies show that cytokines are important mediators of melioidosis progression and low neutrophil counts are associated with progression of its severity. However, to date, there are no reports on cytokine production in neutropenic cancer patients who are prone to melioidosis. Hence, here we assessed the cytokine production in neutropenic AML patients by introducing B. pseudomallei to their peripheral blood mononuclear cell (PBMC) culture in vitro. We observed that inflammatory response related cytokines namely TNF-α, IFN-γ IL-6 and IL-10 were highly circulated in infected PBMCs suggesting that these cytokines may play important roles in the progression of severity in melioidosis infected neutropenic patients.
4.Antibacterial and antibiotic potentiating capabilities of extracts isolated from Burkillanthus malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus against human pathogenic bacteria
Kathirvalu, G. ; Chandramathi, S. ; Azahar, S.A. ; Atiya, N. ; Begum, S. ; Christophe, W. ; Sulaiman, M. ; Abdullah, N. ; Mani, R.R. ; Jindal, H.M. ; Zulkipli, M.
Tropical Biomedicine 2023;40(No.2):152-159
Antibiotics which once a boon in medicine and saved millions of lives are now facing an ever-growing
menace of antibacterial resistance, which desperately needs new antibacterial drugs which are innovative
in chemistry and mode of action. For many years, the world has turned to natural plants with antibacterial
properties to combat antibiotic resistance. On that basis, we aimed to identify plants with antibacterial
and antibiotic potentiating properties. Seventeen different extracts of 3 plants namely Burkillanthus
malaccensis, Diospyros hasseltii and Cleisthanthus bracteosus were tested against multi-drug resistant
Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Methicillinresistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA).
Antibacterial activity of hexane, methanol and chloroform extracts of bark, seed, fruit, flesh and leaves
from these plants were tested using, disk diffusion assay, minimum inhibitory concentration (MIC) and
minimum bactericidal concentration (MBC) assays. Antibiotic potentiating capabilities were tested using
time-kill assay. B. malaccensis fruit chloroform extract showed the biggest zone of inhibition against MRSA
(13.00±0.0 mm) but C. bracteosus bark methanol extract showed the biggest inhibition zone against
MSSA (15.33±0.6 mm). Interestingly, bark methanol extract of C. bracteosus was active against MRSA
(8.7±0.6 mm), MSSA (7.7±0.6 mm) (Gram-positive) and A. baumannii (7.7±0.6 mm) (Gram-negative).
Overall, the leaf methanol and bark methanol extract of C. bracteosus warrants further investigation
such as compound isolation and mechanism of action for validating its therapeutic use as antibiotic
potentiator importantly against MRSA and A. baumannii.