Journal of Microbiology

Journal Article

Water-based extracts of Zizania latifolia inhibit Staphylococcus aureus infection through the induction of human beta-defensin 2 expression in HaCaT cells: Bo Yeon Kang , Seung-Su Lee , Myun-Ho Bang , Hyoik Jeon , Hangeun Kim , Dae Kyun Chung; J. Microbiol. 2018;56(12):910-916. Published online November 27, 2018; DOI: https://doi.org/10.1007/s12275-018-8307-9

Abstract: Zizania latifolia is a perennial herb belonging to the family Gramineae that has been used as a health food in Asian countries. In this study, we investigated the antimicrobial effect of Z. latifolia, which increased human beta-defensin 2 (hBD2) expression in HaCaT cells. hBD2 expression was further increased in cells treated with Z. latifolia extracts and subsequently infected with Staphylococcus aureus. Inversely, S. aureus infection decreased after treatment. The induction of hBD2 in HaCaT cells was mediated by the Toll-like receptor 2 (TLR2) signaling pathway, including the activation of extracellular signal-regulated kinase (ERK) and activator protein 1 (AP-1). Further study using siRNA revealed that hBD2 played an important role in the inhibition of S. aureus infection in HaCaT cells. Our data suggest that Z. latifolia extracts can be used as an antimicrobial ingredient for skin treatment formulas.

Review

Minireivew] Protective Role of Gut Commensal Microbes against Intestinal Infections: My Young Yoon , Keehoon Lee , Sang Sun Yoon; J. Microbiol. 2014;52(12):983-989. Published online November 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4655-2

Abstract: The human gastrointestinal tract is colonized by multitudes of microorganisms that exert beneficial effects on human health. Mounting evidence suggests that intestinal microbiota contributes to host resistance against enteropathogenic bacterial infection. However, molecular details that account for such an important role has just begun to be understood. The commensal microbes in the intestine regulate gut homeostasis through activating the development of host innate immunity and producing molecules with antimicrobial activities that directly inhibit propagation of pathogenic bacteria. Understanding the protective roles of gut microbiota will provide a better insight into the molecular basis that underlies complicated interaction among host-pathogen-symbiont. In this review, we highlighted recent findings that help us broaden our knowledge of the intestinal ecosystem and thereby come up with a better strategy for combating enteropathogenic infection.

Research Support, N.I.H., Extramural

The Activity of a Small Lytic Peptide PTP-7 on Staphylococcus aureus Biofilms: Riddhi Kharidia , Jun F. Liang; J. Microbiol. 2011;49(4):663-668. Published online September 2, 2011; DOI: https://doi.org/10.1007/s12275-011-1013-5

Abstract: One of the most important features of bacterial biofilms is their resistance to antibiotics and to the host immune system. In this study, we have found that a small lytic peptide, PTP-7, is very potent to Gram-positive bacteria and is able to kill antibiotic sensitive and resistant Staphylococcus aureus indiscriminately. Further studies have revealed that despite being a cationic peptide, the antibacterial activity of PTP-7 was not affected by the negatively charged extracellular polymeric substance (EPS) of biofilms. PTP-7 could diffuse into the deep layer of S. aureus biofilms to kill bacteria inside biofilms efficiently and effectively. Neither the high concentrations of metal ions nor the acidic pH in biofilms affected the activity of peptide PTP-7. It seems that the unique sequence/structure together with the resistant bacteria killing ability of peptide PTP-7 confers its anti-biofilm activity. This study sheds new light on the treatment of bacterial biofilms, especially various biofilm related infections.

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

Enteric Bacteria Isolated from Acute Diarrheal Patients in the Republic of Korea between the Year 2004 and 2006: Seung-Hak Cho , Hyun-Ho Shin , Yeon-Hwa Choi , Mi-Sun Park , Bok-Kwon Lee; J. Microbiol. 2008;46(3):325-330. Published online July 5, 2008; DOI: https://doi.org/10.1007/s12275-008-0015-4

Abstract: In an epidemiological survey of human enterobacterial infections in the Republic of Korea during three years from 2004 to 2006, we isolated 1,784 (6.2%, isolation rate of enteropathogens from stool samples) in 2004, 2,547 (9.5%) in 2005 and 3,506 bacteria (12.3%) from people who visited clinics. Among the isolated bacteria, pathogenic Escherichia coli, especially, EAEC was the most frequently identified pathogen in both urban and rural regions followed by Staphylococcus aureus, Salmonella species, Bacillus cereus, Vibrio parahaemolyticus, Campylobacter jejuni, Clostridium perfringens, and Shigella species. Distinct seasonality was found in V. parahaemolyticus species, while this pathogen showed no age-specific patterns. However, other bacteria, i.e., pathogenic E. coli, S. aureus, Salmonella spp., and B. cereus showed similar seasonality throughout the year, showing a slight increase in the infection rate during the summer months and high prevalence among children under 10 years of age and elder-age people. The antibiotic susceptibility patterns of pathogenic E. coli, Salmonella spp., and S. aureus showed high resistance to penicillins. However, both pathogenic E. coli and Salmonella spp. were susceptible to several cephems, imipenem, and amikacin. Moreover, S. aureus strains resistant to vancomycin were not found. In conclusion, these surveillances can play an important role for the control and prevention to the diseases originated by enteritis bacteria.

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