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Antimicrobial efficacy and activity of ethanolic extract of Piper betle L. on Staphylococcus aureus-infected wound in mice and clinical isolates of multiple drug-resistant bacterial pathogens

Valle DLJ, Puzon JJM, Cabrera EC, Cena-Navarro RB, Rivera WL

Trop Biomed, 2021 Jun 01;38(2):134-142.
PMID: 34172702 DOI: 10.47665/tb.38.2.049

This study aimed to determine the in vivo effectiveness of the ethanolic extract of Piper betle L. leaves against Staphylococcus aureus-infected wounds in mice and its antimicrobial properties on clinical isolates of multiple drug-resistant bacterial pathogens. Twenty mice were divided into four groups. Wounds were created in all mice under anesthesia by excision from the dorsal skin down to the subcutaneous fat and inoculating with S. aureus. After 24 h, the wound of each mouse was treated once daily by application of the respective cream. Group I was treated with mupirocin antibacterial cream; Group II received a cream base containing no active ingredient; Groups III and IV were treated with 2.5% and 5.0% concentrations of P. betle cream, respectively. Further, an in vitro study was performed by adding undiluted, 1:50 and 1:100 dilutions of the four studied creams in normal saline containing 1.5 × 108 CFU/mL of the following bacteria: antimicrobial-susceptible S. aureus, Escherichia coli, Pseudomonas aeruginosa, methicillin-resistant S. aureus, extended-spectrum β-lactamase-producing Escherichia coli, vancomycin-resistant Enterococcus, metallo-βlactamase-producing P. aeruginosa and carbapenem-resistant Klebsiella pneumoniae. The mice in Groups III and IV had significantly faster wound contraction and significantly shorter reepithelialization time than Group II (p < 0.05), which were not significantly different from Group I (p > 0.05). P. betle creams inhibited all studied bacterial strains at full concentration and at a dilution of 1:50. The inhibitory effect was more significant than Groups I and II (p < 0.05), except on S. aureus. Specifically, S. aureus inhibition was not significantly different for Groups III and IV (p > 0.05) when compared with Group I. Cream formulations derived from P. betle ethanolic extract have great potential as antimicrobial agents for the treatment of wound infection. Further clinical tests are recommended to determine the safety and efficacy of these formulations in other mammalian species.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects
Fulltext An antimicrobial compound isolated from Cinnamomum iners leaves with activity against methicillin-resistant Staphylococcus aureus

Mustaffa F, Indurkar J, Ismail S, Shah M, Mansor SM

Molecules, 2011 Apr 08;16(4):3037-47.
PMID: 21478819 DOI: 10.3390/molecules16043037

This study was designed to investigate the antimicrobial activity of Cinnamomum iners standardized leave methanolic extract (CSLE), its fractions and isolated compounds. CSLE and fractions were subjected to disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests using different Gram positive and Gram negative bacteria and yeast. Within the series of fractions tested, the ethyl acetate fraction was the most active, particularly against methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli, with MIC values of 100 and 200 µg/mL, respectively. The active compound in this fraction was isolated and identified as xanthorrhizol [5-(1, 5-dimethyl-4-hexenyl)-2-methylphenol] by various spectroscopic techniques. The overall results of this study provide evidence that Cinnamomum iners leaves extract as well as the isolated compound xanthorrhizol exhibit antimicrobial activity for both Gram negative and Gram positive pathogens, especially against MRSA strains.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext Vancomycin treatment failure in a vancomycin susceptible methicillin-resistant Staphylococcus aureus (MRSA) infected patient

Norazah A, Salbiah N, Nurizzat M, Santhana R

Med J Malaysia, 2009 Jun;64(2):166-7.
PMID: 20058580 MyJurnal

A 64-year old patient, who had bacteraemia, did not respond to vancomycin despite the MRSA isolate being sensitive to the antibiotic at MIC 2 microg/mL. Electron microscopy of the MRSA isolate showed thickening of the cell wall, which was not observed in MRSA with lower vancomycin MIC.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Inhibitory and resistance-modifying potential of plant-based alkaloids against methicillin-resistant Staphylococcus aureus (MRSA)

Mohtar M, Johari SA, Li AR, Isa MM, Mustafa S, Ali AM, et al.

Curr Microbiol, 2009 Aug;59(2):181-6.
PMID: 19475447 DOI: 10.1007/s00284-009-9416-9

Increased prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has become a major threat to the health sector worldwide due to their virulence, limited therapeutic options and their distribution in both hospital and community settings. Discovery and development of new anti-MRSA agents as alternatives to the very few antibiotics left in the armamentarium are, thus, urgently required. Recently, an efflux mechanism in MRSA has been identified as one of the main contributors of resistance towards various structurally unrelated antibiotics. The potential of reserpine (a phytoalkaloid) as efflux pump inhibitor (EPI) against various microbes remains limited as the concentration needed for inhibition is toxic to humans. This study therefore aimed to evaluate 13 alkaloid compounds as potential inhibitory agents and/or potential EPIs against a panel of three MRSA isolates which not only differ in their susceptibility to vancomycin (amongst the last drugs available to treat serious MRSA infection), but also exhibited active efflux activity. Results indicated berberine's moderate inhibitiory activity against two MRSA isolates scoring a minimum inhibitory concentration (MIC) value of 125 microg/ml. Notable efflux inhibitory activity (ranging from two- to eightfold Ethidium Bromide MIC reduction) meanwhile was detected from quinine, piperine and harmaline using reserpine as the positive control. Findings from this study support the opinion that a vast number of potential phytocompounds with pharmacological potential await discovery. Therapeutic application of these compounds, however, warrants further investigation to ascertain their pharmacodynamics and safety aspects.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Could bacteriophages isolated from the sewage be the solution to methicillin-resistant Staphylococcus aureus?

Tan CS, Aqiludeen NA, Tan R, Gowbei A, Mijen AB, Santhana Raj L, et al.

Med J Malaysia, 2020 03;75(2):110-116.
PMID: 32281590

INTRODUCTIONS: The emergence of multidrug-resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA) complicates the treatment of the simplest infection. Although glycopeptides such as vancomycin still proves to be effective in treating MRSA infections, the emergence of vancomycin-resistant strains limits the long term use of this antibiotic. Bacteriophages are ubiquitous bacterial viruses which is capable of infecting and killing bacteria including its antibiotic-resistant strains. Bactericidal bacteriophages use mechanisms that is distinct from antibiotics and is not affected by the antibioticresistant phenotypes.
OBJECTIVES: The study was undertaken to evaluate the possibility to isolate bacteriolytic bacteriophages against S.aureus from raw sewage water and examine their efficacy as antimicrobial agents in vitro.
METHODS: Bacteriophages were isolated from the raw sewage using the agar overlay method. Isolated bacteriophages were plaque purified to obtain homogenous bacteriophage isolates. The host range of the bacteriophages was determined using the spot test assay against the 25 MRSA and 36 MSSA isolates obtained from the Sarawak General Hospital. Staphylococcus saprophyticus, Staphylococcus sciuri and Staphylococcus xylosus were included as non-SA controls. The identity of the bacteriophages was identified via Transmission Electron Microscopy and genomic size analysis. Their stability at different pH and temperature were elucidated.
RESULTS: A total of 10 lytic bacteriophages infecting S.aureus were isolated and two of them namely ΦNUSA-1 and ΦNUSA-10 from the family of Myoviridae and Siphoviridae respectively exhibited exceptionally broad host range against >80% of MRSA and MSSA tested. Both bacteriophages were specific to S.aureus and stable at both physiologic pH and temperature.
CONCLUSION: This study demonstrated the abundance of S.aureus specific bacteriophages in raw sewage. Their high virulence against both MSSA and MRSA is an excellent antimicrobial characteristic which can be exploited for bacteriophage therapy against MRSA.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Synergistic Effect of Polyalthia longifolia Leaf and Antibiotics against Clinical Isolates of Methicillin-Resistant Staphylococcus aureus (MRSA) by Microscopic Technique

Kirubakari B, Chen Y, Sasidharan S

Antiinflamm Antiallergy Agents Med Chem, 2020;19(3):323-334.
PMID: 31113347 DOI: 10.2174/1871523018666190522112902

BACKGROUND: Polyalthia longifolia is a popular medicinal plant and has been widely used as a traditional remedy for centuries in curing of various ailments. The purpose of this study was conducted to determine the in situ antimicrobial synergistic effects between Polyalthia longifolia leaf ethyl acetate fraction (PLEAF) and ampicillin against MRSA local isolate by using modern microscopy technique.
METHODS: Hence, the evaluation of the synergistic activity of PLEAF and ampicillin against MRSA local isolate was conducted with scanning electron microscopy (SEM).
RESULTS: The combinational effect of PLEAF fraction and ampicillin exhibited significant antibacterial activity against MRSA. Bacterial cells observations showed invagination, impaired cell division, extensive wrinkles, cell shrinkage, the appearance of a rougher cell with fibrous matrix and clustered cells which confirmed the synergistic effect of PLEAF and ampicillin against MRSA local isolate by SEM.
CONCLUSION: Conclusively, the in situ SEM observation proved the synergistic antimicrobial activity between PLEAF fraction and ampicillin to destroy the MRSA resistance bacteria which is an important aspect of PLEAF fraction to be used in the future combinational therapy.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Increased vancomycin minimum inhibitory concentration among Staphylococcus aureus isolates in Malaysia

Ahmad N, Nawi S, Rajasekaran G, Maning N, Aziz MN, Husin A, et al.

J Med Microbiol, 2010 Dec;59(Pt 12):1530-1532.
PMID: 20724515 DOI: 10.1099/jmm.0.022079-0
Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Bacterial mediated silver nanoparticles and their efficacy against MRSA

Saleem S, Iqbal A, Hasnain S

Trop Biomed, 2020 Jun 01;37(2):482-488.
PMID: 33612817

Bacterial mediated Silver nanoparticles is considered as an emerging Ecofriendly approach to eradicate human pathogens. This paper aims to provide the biological approach for the synthesis of silver nanoparticles from indigenously isolated bacteria. This study will be beneficial to control the nosocomial infections triggered by MRSA (Methicillin-resistant Staphylococcus aureus). The current study is the extracellular synthesis of silver nanoparticles by using the cell free filtrate of bacterial strains isolated from the soil. The optimization study was also carried out to obtain the maximum production of silver nanoparticles. Nanoparticles were confirmed and characterized by UV-Vis spectroscopy and Transmission Electron Microscopy (TEM) having the plasmon resonance peak between 420-450nm with 10-60nm in size range and most were spherical in shape. Synthesized silver nanoparticles showed a potential antibacterial activity against MRSA (Methicillin Resistant Staphylococcus aureus) in-vitro study. This is the green approach for the production of AgNPs, as there was no previous work done on the synthesis of silver nanoparticles by bacteria in this region of Southern Punjab, Pakistan and these nanoparticles can be used to treat nosocomial infection. These silver nanoparticles can be used in effective disease management as antimicrobial agent.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext Preliminary Insight of Pyrrolylated-Chalcones as New Anti-Methicillin-Resistant Staphylococcus aureus (Anti-MRSA) Agents

Gunasekharan M, Choi TI, Rukayadi Y, Mohammad Latif MA, Karunakaran T, Mohd Faudzi SM, et al.

Molecules, 2021 Sep 01;26(17).
PMID: 34500755 DOI: 10.3390/molecules26175314

Bacterial infections are regarded as one of the leading causes of fatal morbidity and death in patients infected with diseases. The ability of microorganisms, particularly methicillin-resistant Staphylococcus aureus (MRSA), to develop resistance to current drugs has evoked the need for a continuous search for new drugs with better efficacies. Hence, a series of non-PAINS associated pyrrolylated-chalcones (1-15) were synthesized and evaluated for their potency against MRSA. The hydroxyl-containing compounds (8, 9, and 10) showed the most significant anti-MRSA efficiency, with the MIC and MBC values ranging from 0.08 to 0.70 mg/mL and 0.16 to 1.88 mg/mL, respectively. The time-kill curve and SEM analyses exhibited bacterial cell death within four hours after exposure to 9, suggesting its bactericidal properties. Furthermore, the docking simulation between 9 and penicillin-binding protein 2a (PBP2a, PDB ID: 6Q9N) suggests a relatively similar bonding interaction to the standard drug with a binding affinity score of -7.0 kcal/mol. Moreover, the zebrafish model showed no toxic effects in the normal embryonic development, blood vessel formation, and apoptosis when exposed to up to 40 µM of compound 9. The overall results suggest that the pyrrolylated-chalcones may be considered as a potential inhibitor in the design of new anti-MRSA agents.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext Antimicrobial and antibiofilm activities of Cu(II) Schiff base complexes against methicillin-susceptible and resistant Staphylococcus aureus

Chung PY, Khoo REY, Liew HS, Low ML

Ann Clin Microbiol Antimicrob, 2021 Sep 24;20(1):67.
PMID: 34560892 DOI: 10.1186/s12941-021-00473-4

BACKGROUND: Methicillin-resistance S. aureus (MRSA) possesses the ability to resist multiple antibiotics and form biofilm. Currently, vancomycin remains the last drug of choice for treatment of MRSA infection. The emergence of vancomycin-resistant S. aureus (VRSA) has necessitated the development of new therapeutic agents against MRSA. In this study, the antimicrobial and antibiofilm activities of two copper-complexes derived from Schiff base (SBDs) were tested individually, and in combination with oxacillin (OXA) and vancomycin (VAN) against reference strains methicillin-susceptible and methicillin-resistant Staphylococcus aureus. The toxicity of the SBDs was also evaluated on a non-cancerous mammalian cell line.
METHODS: The antimicrobial activity was tested against the planktonic S. aureus cells using the microdilution broth assay, while the antibiofilm activity were evaluated using the crystal violet and resazurin assays. The cytotoxicity of the SBDs was assessed on MRC5 (normal lung tissue), using the MTT assay.
RESULTS: The individual SBDs showed significant reduction of biomass and metabolic activity in both S. aureus strains. Combinations of the SBDs with OXA and VAN were mainly additive against the planktonic cells and cells in the biofilm. Both the compounds showed moderate toxicity against the MRC5 cell line. The selectivity index suggested that the compounds were more cytotoxic to S. aureus than the normal cells.
CONCLUSION: Both the SBD compounds demonstrated promising antimicrobial and antibiofilm activities and have the potential to be further developed as an antimicrobial agent against infections caused by MRSA.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Phytochemical constituents from Cassia alata with inhibition against methicillin-resistant Staphylococcus aureus (MRSA)

Hazni H, Ahmad N, Hitotsuyanagi Y, Takeya K, Choo CY

Planta Med, 2008 Dec;74(15):1802-5.
PMID: 18991205 DOI: 10.1055/s-0028-1088340

The methanolic extract of the leaves of CASSIA ALATA was sequentially partitioned in increasing polarity to afford the hexane, chloroform, butanol and residual extract. Crude extracts were evaluated against MRSA using the agar well diffusion assay. The butanol and chloroform extracts both exhibited inhibition against MRSA with inhibition indexes of 1.03 +/- 0.16 and 0.78 +/- 0.07 at the concentration of 50 mg/mL. The butanol extracts were further purified using silica gel and reverse phase chromatography to afford kaempferol ( 1), kaempferol 3- O-beta-glucopyranoside ( 2), kaempferol 3- O-gentiobioside ( 3) and aloe emodin ( 4). The four constituents showed varying degrees of inhibition against MRSA. Both 1 and 4 exhibited MIC (50) values of 13.0 +/- 1.5 microg/mL and 12.0 +/- 1.5 microg/mL, respectively. The kaempferol glycosides 2 and 3 were less active with MIC (50) values of 83.0 +/- 0.9 microg/mL and 560.0 +/- 1.2 microg/mL, respectively. A free hydroxyl group at C-3 of the flavonol structure is a structural requirement for the inhibition of MRSA.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext Antibacterial and Antibiofilm Activities of Nonpolar Extracts of Allium stipitatum Regel. against Multidrug Resistant Bacteria

Karunanidhi A, Ghaznavi-Rad E, Hamat RA, Pichika MR, Lung LTT, Mohd Fauzi F, et al.

Biomed Res Int, 2018;2018:9845075.
PMID: 30105271 DOI: 10.1155/2018/9845075

The present study assessed the in vitro antibacterial and antibiofilm potential of hexane (ASHE) and dichloromethane (ASDE) extracts of Allium stipitatum (Persian shallot) against planktonic cells and biofilm structures of clinically significant antibiotic resistant pathogens, with a special emphasis on methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), and emerging pathogens, Acinetobacter baumannii and Stenotrophomonas maltophilia. Antibacterial activities were determined through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill kinetics, and electron microscopy. Antibiofilm activity was assessed by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide] reduction assay and by confocal laser scanning microscopy (CLSM). The zone of inhibition ranged from 13 to 33 mm, while the MICs and MBCs ranged from 16 to 1024 μg mL-1. Both ASHE and ASDE completely eradicated overnight cultures of the test microorganisms, including antibiotic resistant strains. Time-kill studies showed that the extracts were strongly bactericidal against planktonic cultures of S. aureus, MRSA, Acinetobacter baumannii, and S. maltophilia as early as 4 hours postinoculation (hpi). ASHE and ASDE were shown to inhibit preformed biofilms of the four biofilm phenotypes tested. Our results demonstrate the potential therapeutic application of ASHE and ASDE to inhibit the growth of gram-positive and gram-negative biofilms of clinical significance and warrant further investigation of the potential of A. stipitatum bulbs against biofilm-related drug resistance.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext Isolation and characterization of cyclo-(tryptophanyl-prolyl) and chloramphenicol from Streptomyces sp. SUK 25 with antimethicillin-resistant Staphylococcus aureus activity

Alshaibani MM, Jalil J, Sidik NM, Edrada-Ebel R, Zin NM

Drug Des Devel Ther, 2016;10:1817-27.
PMID: 27330275 DOI: 10.2147/DDDT.S101212

BACKGROUND: Zingiber spectabile, commonly known as Beehive Ginger, is used as an ethnobotanical plant in many countries as an appetizer or to treat stomachache, toothache, muscle sprain, and as a cure for swelling, sores and cuts. This is the first report of isolation of Streptomyces strain from the root of this plant. Strain Universiti Kebangsaan 25 (SUK 25) has a very high activity to produce secondary metabolites against methicillin-resistant Staphylococcus aureus (MRSA), which is associated with high morbidity and mortality rates due to acquired multidrug resistance genes and causes medication failure in some clinical cases worldwide. Phylogenetic analysis based on the 16S ribosomal RNA gene sequence exhibited that the most closely related strain was Streptomyces omiyaensis NBRC 13449T (99.0% similarity).
AIM: This study was conducted to carry out the extraction, identification, and biological evaluation of active metabolites isolated from SUK 25 against three MRSA strains, namely, MRSA ATCC 43300, MRSA ATCC 33591, and MRSA ATCC 49476.
MATERIALS AND METHODS: The production of secondary metabolites by this strain was optimized through Thronton's media. Isolation, purification, and identification of the bioactive compounds were carried out using reversed-phase high-performance liquid chromatography, high-resolution mass spectrometry, Fourier transform infrared, and one-dimensional and two-dimensional nuclear magnetic resonance.
RESULTS: During screening procedure, SUK 25 exhibited good antimicrobial potential against several strains of MRSA. The best biological activity was shown from fraction number VII and its subfractions F2 and F3 with minimum inhibitory concentration values at 16 µg/mL and 8 µg/mL, respectively. These two subfractions were identified as diketopiperazine cyclo-(tryptophanyl-prolyl) and chloramphenicol.
CONCLUSION: On the basis of obtained results, SUK 25 isolated from Z. spectabile can be regarded as a new valuable source to produce secondary metabolites against bacteria, especially MRSA.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects
Fulltext Bacteriostatic antimicrobial combination: antagonistic interaction between epsilon-viniferin and vancomycin against methicillin-resistant Staphylococcus aureus

Basri DF, Xian LW, Abdul Shukor NI, Latip J

Biomed Res Int, 2014;2014:461756.
PMID: 24783205 DOI: 10.1155/2014/461756

Stilbenoids have been considered as an alternative phytotherapeutic treatment against methicillin-resistant Staphylococcus aureus (MRSA) infection. The combined effect of ε-viniferin and johorenol A with the standard antibiotics, vancomycin and linezolid, was assessed against MRSA ATCC 33591 and HUKM clinical isolate. The minimum inhibitory concentration (MIC) value of the individual tested compounds and the fractional inhibitory concentration index (FICI) value of the combined agents were, respectively, determined using microbroth dilution test and microdilution checkerboard (MDC) method. Only synergistic outcome from checkerboard test will be substantiated for its rate of bacterial killing using time-kill assay. The MIC value of ε -viniferin against ATCC 33591 and johorenol A against both strains was 0.05 mg/mL whereas HUKM strain was susceptible to 0.1 mg/mL of ε-viniferin. MDC study showed that only combination between ε-viniferin and vancomycin was synergistic against ATCC 33591 (FICI 0.25) and HUKM (FICI 0.19). All the other combinations (ε-viniferin-linezolid, johorenol A-vancomycin, and johorenol A-linezolid) were either indifferent or additive against both strains. However, despite the FICI value showing synergistic effect for ε-viniferin-vancomycin, TKA analysis displayed antagonistic interaction with bacteriostatic action against both strains. As conclusion, ε-viniferin can be considered as a bacteriostatic stilbenoid as it antagonized the bactericidal activity of vancomycin. These findings therefore disputed previous report that ε-viniferin acted in synergism with vancomycin but revealed that it targets similar site in close proximity to vancomycin's action, possibly at the bacterial membrane protein. Hence, this combination has a huge potential to be further studied and developed as an alternative treatment in combating MRSA in future.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Diversity in the antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus clones

Ghaznavi-Rad E, Neela V, Nor Shamsudin M, Ghasemzadeh Moghaddam H, Tavakol M, van Belkum A, et al.

Eur J Clin Microbiol Infect Dis, 2012 Dec;31(12):3317-21.
PMID: 23010901 DOI: 10.1007/s10096-012-1698-3

Methicillin-resistant Staphylococcus aureus (MRSA) is well known for its epidemicity, with the emergence of new clones on a daily basis. Diversity in the clonal types of MRSA challenges the success of treatment, as different clones respond to different sets of antibiotics. However, the antibiotic susceptibility among the isolates within the same clones is largely unexplored. In a previous study on MRSA epidemiology in Malaysia, we identified six major clonal complexes (ST-239-CC8, ST-1-CC1, ST-188-CC1, ST-22-CC22, ST-7-CC7 and ST-1283-CC8). In the present study, we investigated the antibiotic susceptibility patterns of isolates of different clones. Three hundred and eighty-nine MRSA isolates were subjected to the disc diffusion test, oxacillin minimum inhibitory concentration (MIC) determination and assessment of the distribution of macrolide, lincosamide and streptogramin B (MLS(B)) resistance genes. Thirty-six different antibiotic profiles were observed: 30 (83.3 %) among ST-239, 2 (5.6 %) among ST-1283 and 1 (2.8 %) each for ST-1, ST-7, ST-22 and ST-188. All ST-239 (362, 9 %) isolates were multiple drug-resistant (MDR; resistant to more than three classes of antibiotics) and had oxacillin MICs >256 mg/l. Among the 385 clindamycin-resistant isolates, 375 (96.4 %) illustrated inducible resistance (D-zone-positive), while 10 (2.6 %) showed constitutive resistance. The vast majority of the macrolide-resistant isolates carried the ermA gene (95.1 %), followed by ermC (12.9 %). Diversity in the antibiotic susceptibilities of isolates within the clones emphasises the need for continuous surveillance of MDR strains to prescribe the correct antibiotic rather than empirical treatment. This will likely reduce the emergence of new endemic or epidemic resistant MRSA clones.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext The presence of heterogeneous vancomycin-lntermediate Staphylococcus aureus (heteroVISA) in a major Malaysian hospital

Norazah A, Law NL, Abd Ghani MK, Salbiah N

Med J Malaysia, 2012 Jun;67(3):269-73.
PMID: 23082415

This study was conducted to detect the presence of heterogenous vancomycin-intermediate Staphylococcus aureus (heteroVISA) among MRSA isolates in a major hospital. Forty-three MRSA isolates with vancomycin MIC 2 microg/ml collected in 2009 was screened for heteroVISA using Etest Glycopeptide Resistance Detection (GRD) and confirmed by population analysis profile-area under curve method. The genetic relatedness of heteroVISA strains with other MRSA was examined by pulsed-field gel electrophoresis (PFGE) method. Two isolates were shown to be heteroVISA and derived from the same clone. This showed that heteroVISA strains were already present among our local strains since 2009 and were genetically related to other susceptible strains.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects
Fulltext Assessment of phytochemical content, polyphenolic composition, antioxidant and antibacterial activities of Leguminosae medicinal plants in Peninsular Malaysia

Chew YL, Chan EW, Tan PL, Lim YY, Stanslas J, Goh JK

BMC Complement Altern Med, 2011;11:12.
PMID: 21306653 DOI: 10.1186/1472-6882-11-12

Many medicinal plants from Leguminosae family can be found easily in Malaysia. These plants have been used as traditional medicines by local ethnic groups, where they are prepared as decoction, pastes for wound infections, and some have been eaten as salad. This paper focused on the assessment of antioxidant potential, antibacterial activity and classes of phytochemicals of nine plants from the Leguminosae family.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects
Antibiograms and molecular subtypes of methicillin-resistant Staphylococcus aureus in local teaching hospital, Malaysia

Thong KL, Junnie J, Liew FY, Yusof MY, Hanifah YA

J Microbiol Biotechnol, 2009 Oct;19(10):1265-70.
PMID: 19884790

The objectives of this study were to determine the antibiotypes, SCCmec subtypes, PVL carriage, and genetic diversity of MRSA strains from a tertiary hospital. Sixtysix MRSA strains were selected randomly (2003, 2004, and 2007) and tested for the Panton-Valentine leukocidin gene, mecA gene, and SCCmec type via a PCR. The antibiograms were determined using a standard disc diffusion method, and the genetic diversity of the isolates was determined by PFGE. Thirty-four antibiograms were obtained, with 55% of the 66 strains exhibiting resistance to more than 4 antimicrobials. All the isolates remained susceptible to vancomycin, and low resistance rates were noted for fusidic acid (11%), rifampicin (11%), and clindamycin acid (19%). The MRSA isolates that were multisensitive (n=12) were SCCmec type IV, whereas the rest (multiresistant) were SCCmec type III. Only two isolates (SCCmec type IV) tested positive for PVL, whereas all the isolates were mecA-positive. The PFGE was very discriminative and subtyped the 66 isolates into 55 pulsotypes (F=0.31-1.0). The multisensitive isolates were distinctly different from the multidrug-resistant MRSA. In conclusion, no vancomycin-resistant isolate was observed. The Malaysian MDR MRSA isolates were mostly SCCmec type III and negative for PVL. These strains were genetically distinct from the SCCmec type IV strains, which were sensitive to SXT, tetracycline, and erythromycin. Only two strains were SCCmec IV and PVL-positive. The infections in the hospital concerned were probably caused by multiple subtypes of MRSA.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects*
Fulltext Ultrastructural Study on the Antibacterial Activity of Artonin E versus Streptomycin against Staphylococcus aureus Strains

Zajmi A, Mohd Hashim N, Noordin MI, Khalifa SA, Ramli F, Mohd Ali H, et al.

PLoS One, 2015;10(6):e0128157.
PMID: 26030925 DOI: 10.1371/journal.pone.0128157

Staphylococci are facultative anaerobes, perfectly spherical un-encapsulated cocci, with a diameter not exceeding 1 micrometer in diameter. Staphylococcus aureus are generally harmless and remain confined to the skin unless they burrow deep into the body, causing life-threatening infections in bones, joints, bloodstream, heart valves and lungs. Among the 20 medically important staphylococci species, Staphylococcus aureus is one of the emerging human pathogens. Streptomycin had its highest potency against Staphylococcus infections despite the likelihood of getting a resistant type of staphylococcus strains. Methicillin-resistant S. aureus (MRSA) is the persister type of Staphylococcus aureus and was evolved after decades of antibiotic misuse. Inadequate penetration of the antibiotic is one of the principal factors related to success/failure of the therapy. The active drug needs to reach the bacteria at concentrations necessary to kill or suppress the pathogen's growth. In turn the effectiveness of the treatment relied on the physical properties of Staphylococcus aureus. Thus understanding the cell integrity, shape and roughness is crucial to the overall influence of the therapeutic agent on S. aureus of different origins. Hence our experiments were designed to clarify ultrastructural changes of S. aureus treated with streptomycin (synthetic compound) in comparison to artonin E (natural compound). In addition to the standard in vitro microbial techniques, we used transmission electron microscopy to study the disrupted cell architecture under antibacterial regimen and we correlate this with scanning electron microscopy (SEM) to compare results of both techniques.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects
Flemingin-Type Prenylated Chalcones from the Sarawak Rainforest Plant Desmodium congestum

Rees KA, Bermudez C, Edwards DJ, Elliott AG, Ripen JE, Seta C, et al.

J Nat Prod, 2015 Aug 28;78(8):2141-4.
PMID: 26284978 DOI: 10.1021/acs.jnatprod.5b00410

In an ongoing program to identify new anti-infective leads, an extract derived from whole plant material of Desmodium congestum collected in the Sarawak rainforest was found to have anti-MRSA activity. Bioassay-guided isolation led to the isolation of two new prenylated chalcones, 5'-O-methyl-3-hydroxyflemingin A (1) and 5'-O-methylflemingin C (2), which were closely related to the flemingins previously isolated from various Flemingia species. Chalcones 1 and 2, which were determined to be 4:6 enantiomeric mixtures by chiral HPLC, exhibited moderate activity against a panel of Gram-positive bacteria and were also cytotoxic to the HEK293 human embryonic kidney cell line.

Matched MeSH terms: Methicillin-Resistant Staphylococcus aureus/drug effects

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