Journal of Microbiology

Journal Articles

Antimicrobial Efficacy of Allium cepa and Zingiber officinale Against the Milk‑Borne Pathogen Listeria monocytogenes: Abirami Arasu , Nagaram Prabha , Durga Devi , Praveen Kumar Issac , Khaloud Mohammed Alarjani , Dunia A. Al Farraj , Reem A. Aljeidi , Dina S. Hussein , Magesh Mohan , Jehad Zuhair Tayyeb , Ajay Guru , Jesu Arockiaraj; J. Microbiol. 2023;61(11):993-1011. Published online December 4, 2023; DOI: https://doi.org/10.1007/s12275-023-00086-w

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Abstract: Listeria monocytogenes is an important food-borne pathogen that causes listeriosis and has a high case fatality rate despite its low incidence. Medicinal plants and their secondary metabolites have been identified as potential antibacterial substances, serving as replacements for synthetic chemical compounds. The present studies emphasize two significant medicinal plants, Allium cepa and Zingiber officinale, and their efficacy against L. monocytogenes. Firstly, a bacterial isolate was obtained from milk and identified through morphology and biochemical reactions. The species of the isolate were further confirmed through 16S rRNA analysis. Furthermore, polar solvents such as methanol and ethanol were used for the extraction of secondary metabolites from A. cepa and Z. officinale. Crude phytochemical components were identified using phytochemical tests, FTIR, and GC–MS. Moreover, the antibacterial activity of the crude extract and its various concentrations were tested against L. monocytogenes. Among all, A. cepa in methanolic extracts showed significant inhibitory activity. Since, the A. cepa for methanolic crude extract was used to perform autography to assess its bactericidal activity. Subsequently, molecular docking was performed to determine the specific compound inhibition. The docking results revealed that four compounds displayed strong binding affinity with the virulence factor Listeriolysin-O of L. monocytogenes. Based on the above results, it can be concluded that the medicinal plant A. cepa has potential antibacterial effects against L. monocytogenes, particularly targeting its virulence.

Biofilm characterization of Fusarium solani keratitis isolate: increased resistance to antifungals and UV light: Itzel Margarita Córdova-Alcántara , Diana Laura Venegas-Cortés , María Ángeles Martínez-Rivera , Néstor Octavio Pérez , Aida Verónica Rodriguez-Tovar; J. Microbiol. 2019;57(6):485-497. Published online May 27, 2019; DOI: https://doi.org/10.1007/s12275-019-8637-2

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42 Citations

Abstract: Fusarium solani has drawn phytopathogenic, biotechnological, and medical interest. In humans, it is associated with localized infections, such as onychomycosis and keratomycosis, as well as invasive infections in immunocompromised patients. One pathogenicity factor of filamentous fungi is biofilm formation. There is still only scarce information about the in vitro mechanism of the formation and composition of F. solani biofilm. In this work, we describe the biofilm formed by a clinical keratomycosis isolate in terms of its development, composition and susceptibility to different antifungals and ultraviolet light (UV) at different biofilm formation stages. We found five biofilm formation stages using scanning electron microscopy: adherence, germination, hyphal development, maturation, and cell detachment. Using epifluorescence microscopy with specific fluorochromes, it was elucidated that the extracellular matrix consists of carbohydrates, proteins, and extracellular DNA. Specific inhibitors for these molecules showed significant biofilm reductions. The antifungal susceptibility against natamycin, voriconazole, caspofungin, and amphotericin B was evaluated by metabolic activity and crystal violet assay, with the F. solani biofilm preformation to 24 h increased in resistance to natamycin, voriconazole, and caspofungin, while the biofilm preformation to 48 h increased in resistance to amphotericin B. The preformed biofilm at 24 h protected and reduced UV light mortality. F. solani isolate could produce a highly structured extra biofilm; its cellular matrix consists of carbohydrate polymers, proteins, and eDNA. Biofilm confers antifungal resistance and decreases its susceptibility to UV light. The fungal biofilm functions as a survival strategy against antifungals and environmental factors.

Research Support, Non-U.S. Gov't

The Identification of Six Novel Proteins with Fibronectin or Collagen Type І Binding Activity from Streptococcus suis Serotype 2: Hui Zhang , Junxi Zheng , Li Yi , Yue Li , Zhe Ma , Hongjie Fan , Chengping Lu; J. Microbiol. 2014;52(11):963-969. Published online October 31, 2014; DOI: https://doi.org/10.1007/s12275-014-4311-x

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16 Citations

Abstract: Streptococcus suis, a major swine pathogen, is an emerging zoonotic agent that causes meningitis and septic shock. Bacterial cell wall and secreted proteins are often involved in interactions with extracellular matrix proteins (ECMs), which play important roles in the initial steps of pathogenesis. In this study, 2D SDS-PAGE, western blotting-based binding affinity measurements, and microtiter plate binding assays were used to identify cell wall and secreted proteins from S. suis that interact with fibronectin and collagen type І. We identified six proteins from S. suis, including three proteins (translation elongation factor G, oligopeptide-binding protein OppA precursor, and phosphoglycerate mutase) that show both fibronectin and collagen type І binding activity. To the best of our knowledge, these three newly identified proteins had no previously reported fibronectin or collagen type І binding activity. Overall, the aim in this study was to identify proteins with ECM binding activity from S. suis and it represents the first report of six new proteins from S. suis that interact with fibronectin or collagen type І.

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