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Biosensor Based on Electrochemical Analysis for Staphylococcus aureus Detection with Molecular Imprinted Polymer Technique
(2025-11-01)
Vongmanee, Naphatsawan
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Nampeng, Jindapa
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Pintavirooj, Chuchart
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Visitsattapongse, Sarinporn
Staphylococcus aureus (S. aureus) is one of the most common hospital-acquired pathogens and poses a serious threat to patients with weakened immune systems. Transmission can occur through foodborne illness, skin infections, abscess formation, and bloodstream invasion. The most severe complication arises when S. aureus infects the heart, leading to valve damage and potentially progressing to heart failure. In addition, many strains have developed strong resistance to conventional antibiotic therapies, making treatment increasingly difficult. These challenges highlight the importance of early detection for effective prevention and management. This research focuses on the development of a polymer composite incorporating hydroxyproline for the preparation of molecularly imprinted polymers (MIPs) designed for the rapid detection of S. aureus. The sensing platform, based on electrochemical principles, enabled sensitive and efficient analysis of bacterial samples. The sensor exhibited a broad analytical range, detecting S. aureus from 1 to 10,000 CFU/mL, with a detection limit as low as 1.031 CFU/mL. Selectivity testing against Pseudomonas aeruginosa, Candida albicans, and Escherichia coli confirmed high specificity toward S. aureus. These findings highlight the potential of this MIP-based electrochemical sensor as a reliable tool for rapid bacterial detection in clinical and environmental settings.
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Enhanced eradication of Staphylococcus aureus biofilms by combination disinfectants: comparative analysis of antimicrobial and anti-biofilm efficacy
(2025-10-01)
Dawan, Jirapat
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Pomseethong, Panalee
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Hwang, Jeong Seon
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Kim, Jae Kyu
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Lee, Sang Soo
Biofilms of Staphylococcus aureus pose significant challenges in various environments due to their resilience against antimicrobial agents. This study evaluated the antimicrobial efficacy of single disinfectant including 0.25% calcium hydroxide, 0.25% sodium hypochlorite, 0.25% deoxycholate, 0.25% poly(vinylpyrrolidone)-iodine complex and combination (0.25%) disinfectant suspensions against S. aureus (SAATCC and SACCARM) biofilms on metal disc surfaces. The results revealed that all treatments significantly reduced biofilm formation compared to the untreated control, with the combination treatment exhibiting the most potent and sustained anti-biofilm activity. After 4 h of incubation, biofilm cells were undetectable under the combination treatment (< 20 CFU/mL), indicating complete eradication. Crystal violet staining and biofilm formation index analysis confirmed that the combination treatment resulted in the lowest biofilm biomass. Additionally, extracellular DNA and polysaccharide levels were markedly reduced, further supporting the disruption of biofilm integrity. Gene expression analysis demonstrated a significant downregulation of biofilm-associated genes, including norB, clpP, clpX, and dnaK, under all treatments, with the combination treatment showing the highest inhibitory effect. Transmission electron microscopy analysis revealed severe morphological alterations and biofilm dispersal in the combination-treated samples. Collectively, these findings suggest that the combination disinfectant formulation is the most effective strategy for eradicating S. aureus biofilms, offering a promising approach for biofilm control in medical, industrial, and environmental applications.
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Antibiofilm strategies using mixed disinfectants and cubosome nanocarriers to combat Staphylococcus aureus on sandblasted stainless steel disc surfaces
(2025-09-01)
Dawan, Jirapat
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Guo, Yuyuan
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Lee, Sang Soo
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Kim, Jin Chul
Bacterial biofilms are complex communities in which microorganisms are adhered and encapsulated in a self-produced extracellular polymeric material (EPS) matrix. Biofilm acts as a protective barrier, enhancing the resistance of bacteria to environmental stressors, cleaning agents and antimicrobial treatments. Therefore, this study aimed to evaluated the effectiveness of a mixed disinfectant suspension (MIX) against Staphylococcus aureus biofilms on sandblasted stainless steel disc surfaces. A cubic phase containing MIX was prepared, and its anti-biofilm ability was assessed in comparison to free MIX. The susceptibility of S. aureus ATCC 15,564 (SAATCC) and multidrug-resistant S. aureus CCARM 3080 (SACCARM) biofilms to single and mixed disinfectants (MIX) was evaluated. The incorporation of MIX into cubosomes was performed to evaluate its potential enhancement in antibiofilm activity. 1% MIX demonstrated the most effective anti-biofilm activity. Extracellular DNA (eDNA) and polysaccharides were also significantly reduced in biofilms treated with 1% MIX. TEM analysis revealed that 1% MIX effectively disrupted bacterial cell clusters within the biofilms. The incorporation of 1% MIX into cubosomes enhanced its antibiofilm activity, with cubosome-encapsulated MIX exhibiting superior results compared to free MIX. This study demonstrates the effectiveness of a mixed disinfectant suspension in reducing S. aureus biofilms on sandblasted stainless steel disc surfaces. Furthermore, the incorporation of MIX into lipid-based nanocarriers, such as cubosomes, enhanced its antibiofilm efficacy compared to the free disinfectant.
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Antibacterial and antibiofilm activities of kaffir lime essential oils and their active constituents against Staphylococcus aureus focusing on sortase A
(2025-01-30)
Pontanayodsakorn, Chayapol
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Eurtivong, Chatchakorn
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Jiamboonsri, Pimsumon
Staphylococcus aureus biofilm has become a global medical concern due to rising antibiotic resistance. This study aimed to evaluate the potential activities of kaffir lime essential oils and their active compounds as alternative anti-S. aureus biofilm agents. The compositions of the essential oils were identified by gas chromatography/mass spectrometry (GC/MS), and their antibacterial activity was determined through broth-microdilution and time-kill assays. Antibiofilm activities were assessed using Congo red agar (CRA) well diffusion method, pre-biofilm inhibition resazurin assay, and post-biofilm inhibition assay. Sortase A (SrtA) inhibition was also investigated using in silico and in vitro approaches. This is followed by morphological studies to observe change in biofilm formations using light and scanning electron microscopy (SEM). Phytochemical analysis revealed that the kaffir lime essential oils from leaves (KLL) and peels (KLP) were primarily composed of the monoterpene aldehyde citronellal (59.13 %) and the monoterpene hydrocarbon (−)-limonene (25.69 %). However, the monoterpenoid alcohols, β-citronellol and terpinen-4-ol, which were the third most abundant compounds in KLL (5.35 %) and KLP (10.87 %), respectively, were selected for further study. All test compounds exhibited anti-Staphylococcal activity with a minimum inhibitory concentration (MIC) range of 0.1–0.3 % v/v. Their inhibition above the MIC levels showed time- and concentration-independence. Among the test compounds, terpinen-4-ol revealed good antibiofilm activity by inhibiting biofilm formation rather than eradicating the established biofilm. However, terpinen-4-ol exhibited weak SrtA inhibition with docking score of 32.58 and in vitro SrtA inhibition of 46.14 ± 3.58 % at 1 % v/v. Interestingly, terpinen-4-ol caused visible damage to the bacterial cell barrier, as revealed by SEM micrographs. These findings suggest the potential use of kaffir lime oils and their active compounds to combat biofilm-forming S. aureus infection.
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Control of salmonella rissen and staphylococcus aureus in fermented beef sausage by a combination of cinnamon and mace oils
(2012-12-01)
Nanasombat, Suree
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Wimuttigosol, Pornpan
The antibacterial effect of cinnamon and mace oils on different food model media was evaluated. All pathogenic bacteria tested (Salmonella Senftenberg, Salmonella Rissen, Staphylococcus aureus and Listeria monocytogenes) were sensitive to cinnamon oil on sausage agar (0.063 mg.mL-1 minimum inhibitory concentrations; MIC), but the spoilage bacterium, Pseudomonas fluorescens was susceptible to this oil on meat agar (0.015 mg.mL-1 MIC). However, S. Rissen was the most resistant bacterium to mace oil on sausage agar (22 mg.mL-1 MIC). Most of the lactic acid bacteria tested (Pediococcus pentosaceus, Lactococcus lactis, Enterococcus faecalis and Enterococcus faecium) were more resistant to mace oil as compared to cinnamon oil. Then, the effect of mixed cinnamon and mace oils at different concentrations on the survival of S. Rissen and Staph. aureus in fermented beef sausages was studied. A cinnamon (1,008 ppm) and mace (1,375 ppm) oil combination effectively decreased Staph. aureus viable counts in fermented beef sausages by 3.70 log CFU.g-1 at the end of fermentation (96 h). However, cinnamon oil (252 ppm) with mace oil (1,375 ppm) was sufficient to decrease viable S. Rissen cells to below detection level (less than 1 log CFU.g-1) in fermented sausages.
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Activity of virgin coconut oil, lauric acid or monolaurin in combination with lactic acid against Staphylococcus aureus
(2012-01-01)
Tangwatcharin, Pussadee
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Khopaibool, Prapaporn
The objective of this study was to investigate the in vitro activities of virgin coconut oil, lauric acid and monolaurin in combination with lactic acid against two strains of Staphylococcus aureus, ATCC 25923 and an isolate from a pig carcass, by determination of Fractional Bactericidal Concentration Index (FBCI), time-kill method, as well as scanning and transmission electron microscopy. Minimum bactericidal concentrations (MBC) of lauric acid, monolaurin and lactic acid were 3.2 mg/ml, 0.1 mg/ml and 0.4% (v/v), respectively. The effects of lauric acid + lactic acid and monolaurin + lactic acid combinations were synergistic against both strains, exhibiting FBCIs of 0.25 and 0.63, respectively. In time-kill studies, lauric acid and monolaurin + lactic acid combinations added at their minimum inhibitory concentrations produced a bactericidal effect. The induction of stress in non-stressed cells was dependent on the type and concentration of antimicrobial. This resulted in a loss and change of the cytoplasm and membrane in cells of the bacterium. In contrast, virgin coconut oil (10%) was not active against S. aureus. The bacterial counts found in pork loin treated with lauric acid and monolaurin alone were significantly higher (p <0.05) than those treated with both lipids in combination with lactic acid at sub-inhibitory concentrations. The color, odor and overall acceptability of the pork loins were adversely affected by treatment with the three lipids and lactic acid alone but when combinations of the agents were used the sensory quality was acceptable.
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Control of pathogenic bacteria in raw pork using organic acid salts in combination with freezing and thawing
(2009-07-01)
Nanasombat, Suree
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Chooprang, Kanyarat
The effect of sodium lactate, sodium acetate and potassium sorbate on growth inhibition of seven bacterial species: Escherichia coli, Listeria monocytogenes, Pseudomonas fluorescens, Salmonella Rissen, Sα lmonellα Typhimurium, Staphylococcus aureus and Yersinia enterocolitica was investigated by determining the minimum inhibitory concentration (MIC) values at pH 4.5-7.0. Sodium lactate and potassium sorbate provided overall greater inhibition to all tested bacterial strains in comparison with sodium acetate. At a low pH level (4.5-5.5), sodium lactate was more effective in inhibiting most tested bacteria than at a high pH level (6.0-7.0). The most sensitive bacteria to sodium lactate at pH 4.5 were L. monocytogenes and E. coli. Potassium sorbate had good inhibitory activity against E. coli and P. fluorescens at pH 4.5-5.0. The pH value had less effect on the antibacterial action of sodium acetate particularly at pH 5.0-6.5. Y. enterocolitica was the most sensitive strain to sodium acetate at pH 4.5-7.0. The effect of these organic acid salts in combination with freezing (-23±2°C for 72 h) and slow thawing on the survival of Salmonella Rissen and S. aureus in pork was investigated. Survival cells of Salmonella Rissen and S. aureus decreased as the freezing time increased. Of all the tested organic acid salts, potassium sorbate showed the greatest inhibitory effect on Salmonella Rissen, while sodium lactate inhibited S. aureus well. These organic acid salts provided a synergistic effect with freezing and thawing on lowering survival of both bacterial species.

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