Journal of Microbiology

Review

Membrane Proteins as a Regulator for Antibiotic Persistence in Gram‑Negative Bacteria: Jia Xin Yee , Juhyun Kim , Jinki Yeom; J. Microbiol. 2023;61(3):331-341. Published online February 17, 2023; DOI: https://doi.org/10.1007/s12275-023-00024-w

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Abstract: Antibiotic treatment failure threatens our ability to control bacterial infections that can cause chronic diseases. Persister bacteria are a subpopulation of physiological variants that becomes highly tolerant to antibiotics. Membrane proteins play crucial roles in all living organisms to regulate cellular physiology. Although a diverse membrane component involved in persistence can result in antibiotic treatment failure, the regulations of antibiotic persistence by membrane proteins has not been fully understood. In this review, we summarize the recent advances in our understanding with regards to membrane proteins in Gram-negative bacteria as a regulator for antibiotic persistence, highlighting various physiological mechanisms in bacteria.

Journal Article

Photodynamic antimicrobial activity of new porphyrin derivatives against methicillin resistant Staphylococcus aureus: Hüseyin Ta&# , Ay&# , Nermin Topalo&# , Vildan Alptüzün; J. Microbiol. 2018;56(11):828-837. Published online October 24, 2018; DOI: https://doi.org/10.1007/s12275-018-8244-7

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Abstract: Methicillin resistant Staphylococcus aureus (MRSA) with multiple drug resistance patterns is frequently isolated from skin and soft tissue infections that are involved in chronic wounds. Today, difficulties in the treatment of MRSA associated infections have led to the development of alternative approaches such as antimicrobial photodynamic therapy. This study aimed to investigate photoinactivation with cationic porphyrin derivative compounds against MRSA in in-vitro conditions. In the study, MRSA clinical isolates with different antibiotic resistance profiles were used. The newly synthesized cationic porphyrin derivatives (PM, PE, PPN, and PPL) were used as photosensitizer, and 655 nm diode laser was used as light source. Photoinactivation experiments were performed by optimizing energy doses and photosensitizer concentrations. In photoinactivation experiments with different energy densities and photosensitizer concentrations, more than 99% reduction was achieved in bacterial cell viability. No decrease in bacterial survival was observed in control groups. It was determined that there was an increase in photoinactivation efficiency by increasing the energy dose. At the energy dose of 150 J/cm2 a survival reduction of over 6.33 log10 was observed in each photosensitizer type. While 200 μM PM concentration was required for this photoinactivation, 12.50 μM was sufficient for PE, PPN, and PPL. In our study, antimicrobial photodynamic therapy performed with cationic porphyrin derivatives was found to have potent antimicrobial efficacy against multidrug resistant S. aureus which is frequently isolated from wound infections.

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

Copper as an Antimicrobial Agent against Opportunistic Pathogenic and Multidrug Resistant Enterobacter Bacteria: Wen-Xiao Tian , Shi Yu , Muhammad Ibrahim , Abdul Wareth Almonaofy , Liu He , Qiu Hui , Zhu Bo , Bin Li , Guan-lin Xie; J. Microbiol. 2012;50(4):586-593. Published online July 21, 2012; DOI: https://doi.org/10.1007/s12275-012-2067-8

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44 Citations

Abstract: Infections by Enterobacter species are common and are multidrug resistant. The use of bactericidal surface materials such as copper has lately gained attention as an effective antimicrobial agent due to its deadly effects on bacteria, yeast, and viruses. The aim of the current study was to assess the antibacterial activity of copper surfaces against Enterobacter species. The antibacterial activity of copper surfaces was tested by overlying 5×106 CFU/ml suspensions of representative Enterobacter strains and comparing bacterial survival counts on copper surfaces at room temperature. Iron, stainless steel, and polyvinylchloride (PVC) were used as controls. The mechanisms responsible for bacterial killing on copper surfaces were investigated by a mutagenicity assay of the D-cycloserin (cyclA gene), single cell gel electrophoresis, a staining technique, and inductively coupled plasma mass spectroscopy. Copper yielded a significant decrease in the viable bacterial counts at 2 h exposure and a highly significant decrease at 4 h. Loss of cell integrity and a significantly higher influx of copper into bacterial cells exposed to copper surfaces, as compared to those exposed to the controls, were documented. There was no increase in mutation rate and DNA damage indicating that copper contributes to bacterial killing by adversely affecting cellular structure without directly targeting the genomic DNA. These findings suggest that copper’s antibacterial activity against Enterobacter species could be utilized in health care facilities and in food processing plants to reduce the bioburden, which would increase protection for susceptible members of the community.

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