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Fulltext Antiviral cationic peptides as a strategy for innovation in global health therapeutics for dengue virus: high yield production of the biologically active recombinant plectasin peptide

Rothan HA, Mohamed Z, Suhaeb AM, Rahman NA, Yusof R

OMICS, 2013 Nov;17(11):560-7.
PMID: 24044366 DOI: 10.1089/omi.2013.0056

Dengue virus infects millions of people worldwide, and there is no vaccine or anti-dengue therapeutic available. Antimicrobial peptides have been shown to possess effective antiviral activity against various viruses. One of the main limitations of developing these peptides as potent antiviral drugs is the high cost of production. In this study, high yield production of biologically active plectasin peptide was inexpensively achieved by producing tandem plectasin peptides as inclusion bodies in E. coli. Antiviral activity of the recombinant peptide towards dengue serotype-2 NS2B-NS3 protease (DENV2 NS2B-NS3pro) was assessed as a target to inhibit dengue virus replication in Vero cells. Single units of recombinant plectasin were collected after applying consecutive steps of refolding, cleaving by Factor Xa, and nickel column purification to obtain recombinant proteins of high purity. The maximal nontoxic dose (MNTD) of the recombinant peptide against Vero cells was 20 μM (100 μg/mL). The reaction velocity of DENV2 NS2B-NS3pro decreased significantly after increasing concentrations of recombinant plectasin were applied to the reaction mixture. Plectasin peptide noncompetitively inhibited DENV2 NS2B-NS3pro at Ki value of 5.03 ± 0.98 μM. The percentage of viral inhibition was more than 80% at the MNTD value of plectasin. In this study, biologically active recombinant plectasin which was able to inhibit dengue protease and viral replication in Vero cells was successfully produced in E. coli in a time- and cost- effective method. These findings are potentially important in the development of potent therapeutics against dengue infection.

Matched MeSH terms: Staphylococcus aureus/drug effects; Staphylococcus aureus/growth & development
Fulltext Composition and Bioactivity of Essential Oil from Citrus grandis (L.) Osbeck 'Mato Peiyu' Leaf

Tsai ML, Lin CD, Khoo KA, Wang MY, Kuan TK, Lin WC, et al.

Molecules, 2017 Dec 05;22(12).
PMID: 29206180 DOI: 10.3390/molecules22122154

'Mato Peiyu' pomelo (Citrus grandis (L.) Osbeck 'Mato Peiyu') leaves from pruning are currently an agricultural waste. The aim of this study was to isolate essential oils from these leaves through steam distillation (SD) and solvent-free microwave extraction (SFME) and to evaluate their applicability to skin care by analyzing their antimicrobial, antioxidant (diphenyl-1-picrylhydrazyl scavenging assay, β-carotene/linoleic acid assay, and nitric oxide scavenging assay), anti-inflammatory (5-lipoxygenase inhibition assay), and antityrosinase activities. The gas chromatography-mass spectrometry results indicated that the main components of 'Mato Peiyu' leaf essential oils were citronellal and citronellol, with a total percentage of 50.71% and 59.82% for SD and SFME, respectively. The highest bioactivity among all assays was obtained for 5-lipoxygenase inhibition, with an IC50 value of 0.034% (v/v). The MIC90 of the antimicrobial activity of essential oils against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans ranged from 0.086% to 0.121% (v/v). Citronellal and citronellol were the main contributors, accounting for at least 54.58% of the essential oil's bioactivity. This paper is the first to report the compositions and bioactivities of 'Mato Peiyu' leaf essential oil, and the results imply that the pomelo leaf essential oil may be applied in skin care.

Matched MeSH terms: Staphylococcus aureus/drug effects; Staphylococcus aureus/growth & development
Fulltext Neonatal septic arthritis

Halder D, Quah BS, Malik AS, Choo KE

Southeast Asian J. Trop. Med. Public Health, 1996 Sep;27(3):600-5.
PMID: 9185277

Neonatal septic arthritis has always been considered as separate from its counterpart in older children. The condition is uncommon but serious. Affected neonates usually survive, but with permanent skeletal deformities. Ten cases of neonatal septic arthritis were diagnosed between January 1989 and December 1993 in the neonatal intensive care units of two referral hospitals in the state of Kelantan, Malaysia. All except one neonate was born prematurely. The mean age of presentation was 15.6 days. Joint swelling (10/10), increased warmth (7/10) and erythema of the overlying skin (7/10) were the common presenting signs. Vague constitutional symptoms preceded the definitive signs of septic arthritis in all cases. The total white cell counts were raised with shift to the left. The knee (60%) was not commonly affected, followed by the hip (13%) and ankle (13%). Three neonates had multiple joint involvement. Coexistence of arthritis with osteomyelitis was observed in seven neonates. The commonest organism isolated was methicillin resistant Staphylococcus aureus (9/10). Needle aspiration was performed in nine neonates and one had incision with drainage. Follow up data was available for five neonates and two of these had skeletal morbidity. Early diagnosis by frequent examination of the joints, prompt treatment and control of nosocomial infection are important for management.

Matched MeSH terms: Staphylococcus aureus
Fulltext Natural Xanthones and Skin Inflammatory Diseases: Multitargeting Mechanisms of Action and Potential Application

Gunter NV, Teh SS, Lim YM, Mah SH

Front Pharmacol, 2020;11:594202.
PMID: 33424605 DOI: 10.3389/fphar.2020.594202

The pathogenesis of skin inflammatory diseases such as atopic dermatitis, acne, psoriasis, and skin cancers generally involve the generation of oxidative stress and chronic inflammation. Exposure of the skin to external aggressors such as ultraviolet (UV) radiation and xenobiotics induces the generation of reactive oxygen species (ROS) which subsequently activates immune responses and causes immunological aberrations. Hence, antioxidant and anti-inflammatory agents were considered to be potential compounds to treat skin inflammatory diseases. A prime example of such compounds is xanthone (xanthene-9-one), a class of natural compounds that possess a wide range of biological activities including antioxidant, anti-inflammatory, antimicrobial, cytotoxic, and chemotherapeutic effects. Many studies reported various mechanisms of action by xanthones for the treatment of skin inflammatory diseases. These mechanisms of action commonly involve the modulation of various pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor α (TNF-α), as well as anti-inflammatory cytokines such as IL-10. Other mechanisms of action include the regulation of NF-κB and MAPK signaling pathways, besides immune cell recruitment via modulation of chemokines, activation, and infiltration. Moreover, disease-specific activity contributed by xanthones, such as antibacterial action against Propionibacterium acnes and Staphylococcus epidermidis for acne treatment, and numerous cytotoxic mechanisms involving pro-apoptotic and anti-metastatic effects for skin cancer treatment have been extensively elucidated. Furthermore, xanthones have been reported to modulate pathways responsible for mediating oxidative stress and inflammation such as PPAR, nuclear factor erythroid 2-related factor and prostaglandin cascades. These pathways were also implicated in skin inflammatory diseases. Xanthones including the prenylated α-mangostin (2) and γ-mangostin (3), glucosylated mangiferin (4) and the caged xanthone gambogic acid (8) are potential lead compounds to be further developed into pharmaceutical agents for the treatment of skin inflammatory diseases. Future studies on the structure-activity relationships, molecular mechanisms, and applications of xanthones for the treatment of skin inflammatory diseases are thus highly recommended.

Matched MeSH terms: Staphylococcus epidermidis
Fulltext Deep vein thrombosis as a rare presentation in a female with anti-neutrophil cytoplasmic antibodies-associated vasculitis

Wan Ghazali WS, Mohammad N, Ismail AM

Arch Rheumatol, 2017 Jun;32(2):171-174.
PMID: 30375559 DOI: 10.5606/ArchRheumatol.2017.6108

This article aims to report a case of a young female patient with anti-neutrophil cytoplasmic antibodies-associated vasculitis complicated with pulmonary renal syndrome, multiple relapses, and who later developed venous thromboembolism. Pulmonary renal syndrome is a well- recognized and lethal complication; however, incidence of venous thromboembolism has not been well-described. In this article, we described a 38-year-old Malay female patient admitted in 2008 with three-month history of peripheral neuropathy of lower limbs and right ankle ulcers. Initial inflammatory markers were high and perinuclear Anti-Neutrophil Cytoplasmic Antibodies were positive. She was diagnosed as anti-neutrophil cytoplasmic antibodies-associated vasculitis and started on intravenous methylprednisolone with methotrexate. She presented with relapse of skin vasculitis complicated with pulmonary renal syndrome after being stable for one year. She was intubated and proceeded with plasmapheresis and hemodialysis. She completed six cycles of cyclophosphamide. Renal biopsy revealed chronic changes consistent with end stage renal disease. She further relapsed in 2011 with nasal blockage, epistaxis, and nasal deviation. Chest X-ray revealed lung nodules. Prednisolone was increased, her symptoms settled, and she was discharged with azathioprine. She was readmitted at the end of the same year due to two-day history of right deep vein thrombosis and she later succumbed to methicillin-resistant Staphylococcus aureus sepsis.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus
A rare case of methicillin resistant Staphylococcus aureus (MRSA) cerebral abscess secondary to conjunctivitis

Gan YK, Azmi AZ, Ghani SA, Samsudin A

Med J Malaysia, 2017 06;72(3):197-198.
PMID: 28733571 MyJurnal

This case report discusses the rare association of cerebral abscess related to conjunctivitis in an otherwise healthy child. A 6 year old boy presented with conjunctivitis was treated with topical antibiotics and resolved after a week. Conjunctival swab cultures grew MRSA. A month later he developed status epileptics and CT scans revealed a large cerebral abscess. He was treated with intravenous antibiotics which covered for MRSA, along with an incision and drainage for the cerebral abscess. Pus cultures grew MRSA. The patient recovered well with no disturbance in visual acuity or visual field. On post-operative follow ups, he had no other neurological deficit apart from a slight limp.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus
Fulltext Genetic mechanisms and correlated risk factors of antimicrobial-resistant ESKAPEE pathogens isolated in a tertiary hospital in Malaysia

Ngoi ST, Chong CW, Ponnampalavanar SSS, Tang SN, Idris N, Abdul Jabar K, et al.

Antimicrob Resist Infect Control, 2021 04 23;10(1):70.
PMID: 33892804 DOI: 10.1186/s13756-021-00936-5

BACKGROUND: Knowledge on the epidemiology, genotypic and phenotypic features of antimicrobial-resistant (AMR) ESKAPEE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli) and their association with hospital-acquired infections (HAIs) are limited in Malaysia. Therefore, we evaluated the AMR features and resistance mechanisms of the ESKAPEE pathogens collected in a tertiary hospital located in the capital of Malaysia.
METHODS: A total of 378 AMR-ESKAPEE strains were obtained based on convenience sampling over a nine-month study period (2019-2020). All strains were subjected to disk diffusion and broth microdilution assays to determine the antimicrobial susceptibility profiles. Polymerase chain reaction (PCR) and DNA sequence analyses were performed to determine the AMR genes profiles of the non-susceptible strains. Chi-square test and logistic regression analyses were used to correlate the AMR profiles and clinical data to determine the risk factors associated with HAIs.
RESULTS: High rates of multidrug resistance (MDR) were observed in A. baumannii, K. pneumoniae, E. coli, and S. aureus (69-89%). All organisms except E. coli were frequently associated with HAIs (61-94%). Non-susceptibility to the last-resort drugs vancomycin (in Enterococcus spp. and S. aureus), carbapenems (in A. baumannii, P. aeruginosa, and Enterobacteriaceae), and colistin (in Enterobacteriaceae) were observed. Both A. baumannii and K. pneumoniae harbored a wide array of extended-spectrum β-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaOXA). Metallo-β-lactamase genes (blaVEB, blaVIM, blaNDM) were detected in carbapenem-resistant strains, at a higher frequency compared to other local reports. We detected two novel mutations in the quinolone-resistant determining region of the gyrA in fluoroquinolone-resistant E. coli (Leu-102-Ala; Gly-105-Val). Microbial resistance to ampicillin, methicillin, and cephalosporins was identified as important risk factors associated with HAIs in the hospital.
CONCLUSION: Overall, our findings may provide valuable insight into the microbial resistance pattern and the risk factors of ESKAPEE-associated HAIs in a tertiary hospital located in central Peninsular Malaysia. The data obtained in this study may contribute to informing better hospital infection control in this region.

Matched MeSH terms: Staphylococcus aureus
Novel Ag/cellulose-doped CeO2 quantum dots for efficient dye degradation and bactericidal activity with molecular docking study

Ikram M, Hayat S, Imran M, Haider A, Naz S, Ul-Hamid A, et al.

Carbohydr Polym, 2021 Oct 01;269:118346.
PMID: 34294353 DOI: 10.1016/j.carbpol.2021.118346

In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO2 quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO2 vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO2 revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO2 and Ag/CNC-CeO2.

Matched MeSH terms: Staphylococcus aureus/drug effects
Streptomyces pluripotens sp. nov., a bacteriocin-producing streptomycete that inhibits meticillin-resistant Staphylococcus aureus

Lee LH, Zainal N, Azman AS, Eng SK, Ab Mutalib NS, Yin WF, et al.

Int J Syst Evol Microbiol, 2014 Sep;64(Pt 9):3297-306.
PMID: 24994773 DOI: 10.1099/ijs.0.065045-0

Two novel actinobacteria, strains MUSC 135(T) and MUSC 137, were isolated from mangrove soil at Tanjung Lumpur, Malaysia. The 16S rRNA gene sequence similarity and DNA-DNA relatedness between strains MUSC 135(T) and MUSC 137 were 100 % and 83±3.2 %, confirming that these two strains should be classified in the same species. Strain MUSC 135(T) exhibited a broad-spectrum bacteriocin against the pathogens meticillin-resistant Staphylococcus aureus (MRSA) strain ATCC BAA-44, Salmonella typhi ATCC 19430(T) and Aeromonas hydrophila ATCC 7966(T). A polyphasic approach was used to study the taxonomy of MUSC 135(T), and it showed a range of phylogenetic and chemotaxonomic properties consistent with those of the genus Streptomyces. The diamino acid of the cell-wall peptidoglycan was ll-diaminopimelic acid. The predominant menaquinones were MK-9(H6), MK-9(H4) and MK-9(H8). Polar lipids detected were a lipid, an aminolipid, a phospholipid, phosphatidylinositol, phosphatidylethanolamine and two glycolipids. The predominant cellular fatty acids (>10.0 %) were anteiso-C15 : 0 (20.8 %), iso-C16 : 0 (18.0 %), iso-C15 : 0 (12.2 %) and anteiso-C17 : 0 (11.6 %). The whole-cell sugars were ribose, glucose and mannose. These results suggested that MUSC 135(T) should be placed within the genus Streptomyces. Phylogenetic analysis based on the 16S rRNA gene sequence exhibited that the most closely related strains were Streptomyces cinereospinus NBRC 15397(T) (99.18 % similarity), Streptomyces mexicanus NBRC 100915(T) (99.17 %) and Streptomyces coeruleofuscus NBRC 12757(T) (98.97 %). DNA-DNA relatedness between MUSC 135(T) and closely related type strains ranged from 26.3±2.1 to 49.6±2.5 %. BOX-PCR fingerprint comparisons showed that MUSC 135(T) exhibited a unique DNA profile. The DNA G+C content determined was 70.7±0.3 mol%. Based on our polyphasic study of MUSC 135(T), the strain merits assignment to a novel species, for which the name Streptomyces pluripotens sp. nov. is proposed. The type strain is MUSC 135(T) ( = MCCC 1K00252(T) = DSM 42140(T)).

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus