Article
Microbiology
Lifeng Li, Jiayue Ma, Ping Cheng, Mingchao Li, Zengyuan Yu, Xiaorui Song, Zhidan Yu, Huiqing Sun, Wancun Zhang, Zhaobao Wang
Summary: In this review, the composition and regulation mechanisms of two-component regulatory systems (TCSs) in Klebsiella pneumoniae were analyzed. The important roles of TCSs in the regulation of virulence, antibiotic resistance, and stress responses were summarized. However, further studies are required to understand the function and regulation mechanism of some TCSs in K. pneumoniae.
MICROBIOLOGICAL RESEARCH
(2023)
Review
Infectious Diseases
Giuseppe Valerio De Gaetano, Germana Lentini, Agata Fama, Francesco Coppolino, Concetta Beninati
Summary: The number of multidrug-resistant bacteria is rapidly spreading worldwide. Multidrug efflux pumps play an important role in antimicrobial resistance as they export harmful substances, leading to multidrug resistance (MDR) and treatment failures. Transcriptional regulators and two-component systems (TCS) control the expression of multidrug efflux pumps. Targeting TCS, along with efflux pump inhibitors, could be a beneficial strategy to combat the growing antibiotic resistance.
Article
Microbiology
Akanksha Rajput, Yara Seif, Kumari Sonal Choudhary, Christopher Dalldorf, Saugat Poudel, Jonathan M. Monk, Bernhard O. Palsson
Summary: TCSs play a crucial role in bacterial pathogenicity and antibiotic resistance. The ESKAPEE pathogens exhibit closed pangenomes for TCS, indicating their potential as drug targets. Mutation in certain TCSs may lead to cell lethality, highlighting their importance in bacterial fitness.
Article
Microbiology
Victor Band, Sarah W. Satola, Richard D. Smith, David A. Hufnagel, Chris Bower, Andrew B. Conley, Lavanya Rishishwar, Suzanne E. Dale, Dwight J. Hardy, Roberto L. Vargas, Ghinwa Dumyati, Marion A. Kainer, Erin C. Phipps, Rebecca Pierce, Lucy E. Wilson, Matthew Sorensen, Erik Nilsson, I. King Jordan, Eileen M. Burd, Monica M. Farley, Jesse T. Jacob, Robert K. Ernst, David S. Weiss
Summary: The study revealed varying levels of colistin heteroresistance among highly drug-resistant carbapenem-resistant Enterobacterales (CRE), with most heteroresistant isolates being misclassified as colistin susceptible by clinical diagnostic testing. The findings from the 2015 study suggest a high frequency of colistin heteroresistance in CRE.
Article
Microbiology
Richard D. Smith, Christi L. McElheny, Jerilyn R. Izac, Francesca M. Gardner, Courtney E. Chandler, David R. Goodlett, Yohei Doi, J. Kristie Johnson, Robert K. Ernst
Summary: In this study, a novel method for identifying colistin resistance in Enterobacter species and Klebsiella aerogenes is developed using MALDI-TOF MS. This method allows for rapid and accurate detection of resistance without the need for antimicrobial susceptibility testing. The study demonstrates that the MS assay is highly correlated with killing efficacy and can effectively predict how colistin would treat an infection. The use of MALDI-TOF MS for early identification of antimicrobial resistance can improve antimicrobial stewardship and patient outcomes.
MICROBIOLOGY SPECTRUM
(2022)
Article
Microbiology
Zhizeng Sun, Timothy Palzkill
Summary: The study identified essential active-site residues of the MCR-1 enzyme using deep sequencing, which are critical for its polymyxin resistance function. Approximately 75% of the residues examined were found to be essential for the enzyme's function, suggesting inhibitors binding near these sites will broadly inhibit MCR-1 and similar enzymes.
Article
Microbiology
Lewis MacDonald, Sean Keenan, Flaviana Di Lorenzo, Nana E. Adade, Dervla T. D. Kenna, Beverley C. C. Millar, John E. E. Moore, Jose Ramos Vivas, Antonio Molinaro, Miguel A. A. Valvano
Summary: Achromobacter species can cause chronic and potentially severe infections in immunocompromised patients, especially in those with cystic fibrosis. Analysis of Achromobacter clinical isolates reveals that intrinsic resistance to the antimicrobial peptide polymyxin B (PmB) is prevalent, and many isolates show increased resistance upon PmB challenge. The analysis of lipid A modifications in Achromobacter isolates shows that PmB-resistant strains display modifications that can enhance resistance to PmB and potentially other antimicrobial peptides.
MICROBIOLOGY SPECTRUM
(2023)
Review
Microbiology
Alexandra A. Guffey, Patrick J. Loll
Summary: VRE poses a serious threat to human health and new therapeutics are urgently needed. The VanRS two-component system, with its key molecules VanS and VanR, may provide a potential target for new treatment options.
Article
Microbiology
Linna Xu, Fen Wan, Hao Fu, Biao Tang, Zhi Ruan, Yonghong Xiao, Qixia Luo
Summary: In our study, we identified mcr-10-carrying isolates, including multidrug-resistant ST11 Klebsiella pneumoniae isolates coharboring mcr-10 and mcr-8 genes, which are resistant to polymyxins and show reduced susceptibility to tigecycline. Through screening 941,449 bacterial genomes in the GenBank database, we found a sporadic distribution of mcr-10-harboring isolates worldwide in various sources, especially in humans, highlighting the need for close monitoring and concern in clinical settings.
MICROBIOLOGY SPECTRUM
(2022)
Review
Microbiology
Augustine Koh Jing Jie, Maytham Hussein, Gauri G. G. Rao, Jian Li, Tony Velkov
Summary: Multidrug-resistant Gram-negative pathogens are a significant public health threat, with limited options for treatment due to the lack of new antibiotics and increasing resistance. Combining conventional antibiotics with non-antibiotics has emerged as a promising strategy for combating these pathogens.
Article
Biochemistry & Molecular Biology
Alicja Sloczynska, Matthew E. Wand, Lucy J. Bock, Stefan Tyski, Agnieszka E. Laudy
Summary: This study investigates the contribution of efflux mechanism to carbapenem resistance in A. baumannii clinical strains. Efflux pump inhibitors reduced carbapenem resistance in some isolates. The presence of AbaR25 resistance island with ISAba1 element was found to be involved in carbapenem resistance.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Review
Microbiology
Lucindo Cardoso de Pina, Fernanda Stephens Hermes da Silva, Teca Calcagno Galvao, Heidi Pauer, Rosana Barreto Rocha Ferreira, L. Caetano M. Antunes
Summary: Adaptation to constantly changing environments is a challenge for bacteria, requiring sophisticated strategies to perceive and respond appropriately. The gastrointestinal environment houses trillions of microorganisms, collectively known as microbiota, which play key roles in host health and pathogen resistance. Bacteria, including Salmonella enterica, utilize two-component systems to monitor their environment and regulate behavior, with potential as targets for antivirulence therapeutics against antibiotic-resistant infections.
CRITICAL REVIEWS IN MICROBIOLOGY
(2021)
Article
Infectious Diseases
Wei Huang, Jinyong Zhang, Shiyi Liu, Chunxia Hu, Min Zhang, Shumin Cheng, Huijuan Yu, Manling Zheng, Jinsong Wu, Yuemei Lu, Quanming Zou, Ruiqin Cui
Summary: This study identified a new drug combination that enhances the antibacterial activity of polymyxin B (PB) and is effective against clinical PB-resistant strains. The findings provide important experimental basis for the development of new antibiotic adjuvant strategies.
INFECTION AND DRUG RESISTANCE
(2022)
Editorial Material
Microbiology
Kerrie L. May
Summary: Purcell and colleagues have discovered that inactivating a single lipid recycling enzyme leads to the accumulation of waste lipid by-products, which inhibit a key factor responsible for polymyxin resistance.
JOURNAL OF BACTERIOLOGY
(2022)
Article
Microbiology
Mengjun Hu, Yuyan Zhang, Xiaozhen Huang, Mu He, Jinyu Zhu, Zengfeng Zhang, Yan Cui, Shoukui He, Xianming Shi
Summary: The PhoPQ two-component system plays a crucial role in the resistance formation of quinolone and cephalosporin-resistant S. Enteritidis. PhoP regulates genes associated with envelope homeostasis, the osmotic stress response, and the redox balance to confer antibiotic resistance. Additionally, PhoQ senses quinolones and cephalosporins by directly binding to them. These findings provide insights into bacterial antibiotic resistance and suggest PhoPQ as a potential drug target for overcoming S. Enteritidis resistance.
Letter
Infectious Diseases
Yun Young Cho, So Yeon Kim, Kwan Soo Ko
INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS
(2021)
Article
Microbiology
Jin Yang Baek, Sun Ju Kim, Juyoun Shin, Yeun-Jun Chung, Cheol-In Kang, Doo Ryeon Chung, Jae-Hoon Song, Kwan Soo Ko
Summary: Genome-wide analysis of 26 penicillin-non-susceptible 19A-ST320 pneumococcal isolates from a hospital in South Korea over 17 years revealed extensive genetic variations, suggesting these isolates might have been introduced from other countries. Recombination events were predicted to play a significant role in the evolution of pneumococci even in limited geographical locations and time periods.
Retraction
Microbiology
Juyoun Shin, Kwan Soo Ko
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2022)
Article
Microbiology
Yun Young Cho, Jee Hong Kim, Hyunkeun Kim, Junghwa Lee, Se Jin Im, Kwan Soo Ko
Summary: This study investigated the characteristics of two main clones of carbapenemase-producing Klebsiella pneumoniae isolates, ST11 and ST307, from South Korea. The findings showed that ST11 isolates had a wide range of characteristics, including serotype and virulence, compared to the more homogeneous ST307 isolates. The wzi14-type among the ST11 isolates exhibited higher virulence, while the ST307 isolates had similar virulence to the wzi14-type ST11 isolates. Therefore, monitoring the detailed serotype is necessary in addition to tracking the introduction and spread of specific clones.
Retraction
Microbiology
So Yeon Kim, Ji-Young Rhee, Kwan Soo Ko
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2023)
Retraction
Microbiology
Juyoun Shin, Jin Yang Baek, Sun Young Cho, Hee Jae Huh, Nam Yong Lee, Jae-Hoon Song, Doo Ryeon Chung, Kwan Soo Ko
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
(2023)
Article
Microbiology
Hyeri Seok, Ji-Young Choi, Michidmaral Ganbold, Jong Hyun Shin, Jooyun Kim, Won Suk Choi, Dae Won Park, Kwan Soo Ko
Summary: Recently, there has been an increase in the number of reported infections caused by non-diphtheriae Corynebacterium spp. in patients, as well as the discovery of novel species of Corynebacterium isolated from humans. We report two cases of human infections caused by Corynebacterium haemomassiliense-like organisms, which were initially unidentified by MALDI-TOF MS analysis. Further analysis using three housekeeping genes and phenotypic features revealed their close relation to the recently described species C. haemomassiliense. These strains were found to be multidrug-resistant but susceptible to vancomycin, meropenem, and linezolid. Our report suggests that these recently described Corynebacterium species may not be limited to a specific region, highlighting the difficulty in classifying the genus Corynebacterium.
CURRENT MICROBIOLOGY
(2023)
Article
Infectious Diseases
Jeongwoo Jo, Wonbeom Park, Dae-Hyuk Kweon, Kwan Soo Ko
Summary: Tigecycline heteroresistance is highly prevalent in Acinetobacter baumannii clinical isolates, reducing the efficacy of tigecycline treatment. This study confirmed the reproducibility and stability of mimicked tigecycline heteroresistance and found that the development of resistance in tigecycline-heteroresistant A. baumannii strains may depend on the selection of a pre-existing resistant subpopulation.
INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS
(2023)
Article
Microbiology
Hyunkeun Kim, Jee Hong Kim, Hongbaek Cho, Kwan Soo Ko
Summary: This study reveals that DNA methyltransferase may regulate persister cell formation in Acinetobacter, while RecC seems to mediate epigenetic regulation of persister cell formation. These findings uncover novel mechanisms of persister cell formation, which are important for the research on antibiotic treatment and antibiotic resistance.
MICROBIOLOGY SPECTRUM
(2022)
Article
Infectious Diseases
Seon-Yeong Kim, Hwi Won Seo, Min-Seon Park, Chul Min Park, Jinho Seo, Jaerang Rho, Subeen Myung, Kwan Soo Ko, Jun-Seob Kim, Choong-Min Ryu
Summary: Researchers have developed a chemical compound called PA108 that enhances the antimicrobial activity of polymyxin B against resistant bacteria, offering a potential solution to antibiotic resistance.
JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
(2023)
Article
Microbiology
Sun Ju Kim, Jeongwoo Jo, Kwan Soo Ko
Summary: This study found that colistin resistance in K. variicola was mediated by the modification of lipid A. Although the isolate was obtained from faecal samples of healthy adults, colistin-resistant K. variicola challenges public health as an opportunistic pathogen.
JOURNAL OF MEDICAL MICROBIOLOGY
(2023)
Article
Infectious Diseases
Yun Young Cho, Kwan Soo Ko
Summary: This study investigated the impact of plasmids bearing carbapenemase genes on the formation of persister cells. Results showed that the ColE-type plasmid with blaOXA-232 significantly increased the formation of persister cells. Transformants with gene deletions showed decreased persister cell formation compared to transformants harboring intact pM5_OXA232. The expression levels of relA and spoT correlated with persister cell formation rates, especially against ciprofloxacin. This study highlights the influence of a small ColE-type plasmid bearing blaOXA-232 on persister cell formation.
JOURNAL OF GLOBAL ANTIMICROBIAL RESISTANCE
(2023)
Article
Infectious Diseases
Jeongwoo Jo, Ji Young Lee, Hongbaek Cho, Kwan Soo Ko
Summary: Recent studies have found that colistin dependence frequently occurs in colistin-susceptible Acinetobacter baumannii isolates. Although the parental strains are resistant, colistin-dependent mutants showed increased susceptibility to other antibiotics, suggesting the possibility of developing strategies to eliminate multidrug-resistant A. baumannii. Combination treatments of colistin with subinhibitory concentrations of other antibiotics, especially amikacin, inhibited the development of colistin dependence and eradicated the strains in in vitro assays.
MICROBIAL DRUG RESISTANCE
(2023)
Article
Cell Biology
Jeongwoo Jo, Ki Tae Kwon, Kwan Soo Ko
Summary: This study investigated the heteroresistance of Acinetobacter baumannii to tigecycline and colistin, and evaluated the effectiveness of combined antibiotic treatment. The findings showed that A. baumannii exhibited heteroresistance to both antibiotics, but the resistant subpopulations were independent from each other. Therefore, the combination of tigecycline and colistin can effectively eliminate this bacterial infection.
JOURNAL OF BIOMEDICAL SCIENCE
(2023)
Article
Cell Biology
Suyeon Park, Hyunkeun Kim, Kwan Soo Ko
Summary: In hypervirulent Klebsiella pneumoniae strains, tigecycline resistance is associated with decreased virulence due to reduced production of capsular polysaccharides (CPS). Transcriptomic analyses revealed downregulation of ompK35 expression in tigecycline-resistant mutants, which overexpressed ompR and negatively regulated ompK35 expression. Tigecycline-resistant and ompR-overexpressed mutants exhibited reduced hypermucoviscosity and virulence, while deletion of ompR restored these phenotypes in tigecycline-resistant mutants.
JOURNAL OF BIOMEDICAL SCIENCE
(2023)
Review
Infectious Diseases
Allison M. Hitchcock, Wesley D. Kufel, Keri A. Mastro Dwyer, Eric F. Sidman
Summary: Lenacapavir is a novel HIV-1 treatment option for patients with multidrug-resistant (MDR) HIV-1 infection. It has a favorable pharmacokinetic profile and has shown good tolerability and efficacy in clinical trials.
INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS
(2024)
Article
Infectious Diseases
Roberta Gagliardini, Alessandro Tavelli, Stefano Rusconi, Sergio Lo Caputo, Vincenzo Spagnuolo, Maria Mercedes Santoro, Andrea Costantini, Alessandra Vergori, Franco Maggiolo, Andrea Giacomelli, Giulia Burastero, Giordano Madeddu, Eugenia Quiros Roldan, Antonella d'Arminio Monforte, Andrea Antinori, Alessandro Cozzi-Lepri
Summary: This study evaluated multiple treatment failures to modern antiretroviral therapy in HIV-infected individuals and found that approximately 4% of them were difficult to treat. The difficult to treat group, compared to the non-difficult to treat group, was characterized by older age, higher prevalence of AIDS, lower CD4+ cell count, and higher risk of treatment failure.
INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS
(2024)
