1
|
Yu H, Xu Y, Imani S, Zhao Z, Ullah S, Wang Q. Navigating ESKAPE Pathogens: Considerations and Caveats for Animal Infection Models Development. ACS Infect Dis 2024. [PMID: 38866389 DOI: 10.1021/acsinfecdis.4c00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
The misuse of antibiotics has led to the global spread of drug-resistant bacteria, especially multi-drug-resistant (MDR) ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). These opportunistic bacteria pose a significant threat, in particular within hospitals, where they cause nosocomial infections, leading to substantial morbidity and mortality. To comprehensively explore ESKAPE pathogenesis, virulence, host immune response, diagnostics, and therapeutics, researchers increasingly rely on necessitate suitable animal infection models. However, no single model can fully replicate all aspects of infectious diseases. Notably when studying opportunistic pathogens in immunocompetent hosts, rapid clearance by the host immune system can limit the expression of characteristic disease symptoms. In this study, we examine the critical role of animal infection models in understanding ESKAPE pathogens, addressing limitations and research gaps. We discuss applications and highlight key considerations for effective models. Thoughtful decisions on disease replication, parameter monitoring, and data collection are crucial for model reliability. By meticulously replicating human diseases and addressing limitations, researchers maximize the potential of animal infection models. This aids in targeted therapeutic development, bridges knowledge gaps, and helps combat MDR ESKAPE pathogens, safeguarding public health.
Collapse
Affiliation(s)
- Haojie Yu
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou 310015, Zhejiang China
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, China
| | - Yongchang Xu
- Key Laboratory of Aging and Cancer Biology of Zhejiang Province, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou 311121, China
| | - Saber Imani
- Shulan International Medical College, Zhejiang Shuren University, Hangzhou 310015, Zhejiang China
| | - Zhuo Zhao
- Department of Computer Science and Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Saif Ullah
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
| | - Qingjing Wang
- Key Laboratory of Artificial Organs and Computational Medicine in Zhejiang Province, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Shulan International Medical College, Zhejiang Shuren University, Hangzhou 310015, Zhejiang China
| |
Collapse
|
2
|
Hernández M, Areche C, Castañeta G, Rojas D, Varas MA, Marcoleta AE, Chávez FP. Dictyostelium discoideum-assisted pharmacognosy of plant resources for discovering antivirulence molecules targeting Klebsiella pneumoniae. Nat Prod Res 2024:1-8. [PMID: 38829280 DOI: 10.1080/14786419.2024.2360166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 05/21/2024] [Indexed: 06/05/2024]
Abstract
The rise of antibiotic-resistant bacterial strains represents an important challenge for global health, underscoring the critical need for innovative strategies to confront this threat. Natural products and their derivatives have emerged as a promising reservoir for drug discovery. The social amoeba Dictyostelium discoideum is a potent model organism in this effort. Employing this invertebrate model, we introduce a novel perspective to investigate natural plant extracts in search of molecules with potential antivirulence activity. Our work established an easy-scalable developmental assay targeting a virulent strain of Klebsiella pneumoniae, with Helenium aromaticum as the representative plant. The main objective was to identify tentative compounds from the Helenium aromaticum extract that attenuate the virulence of K. pneumoniae virulence without inducing cytotoxic effects on amoeba cells. Notably, the methanolic root extract of H. aromaticum fulfilled these prerequisites compared to the dichloromethane extract. Using UHPLC Q/Orbitrap/ESI/MS/MS, 63 compounds were tentatively identified in both extracts, 47 in the methanolic and 29 in the dichloromethane, with 13 compounds in common. This research underscores the potential of employing D. discoideum-assisted pharmacognosy to discover new antivirulence agents against multidrug-resistant pathogens.
Collapse
Affiliation(s)
- Marcos Hernández
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Carlos Areche
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Grover Castañeta
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Diego Rojas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Andrés E Marcoleta
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| |
Collapse
|
3
|
Rojas D, Marcoleta AE, Gálvez-Silva M, Varas MA, Díaz M, Hernández M, Vargas C, Nourdin-Galindo G, Koch E, Saldivia P, Vielma J, Gan YH, Chen Y, Guiliani N, Chávez FP. Inorganic Polyphosphate Affects Biofilm Assembly, Capsule Formation, and Virulence of Hypervirulent ST23 Klebsiella pneumoniae. ACS Infect Dis 2024; 10:606-623. [PMID: 38205780 DOI: 10.1021/acsinfecdis.3c00509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The emergence of hypervirulent Klebsiella pneumoniae (hvKP) strains poses a significant threat to public health due to high mortality rates and propensity to cause severe community-acquired infections in healthy individuals. The ability to form biofilms and produce a protective capsule contributes to its enhanced virulence and is a significant challenge to effective antibiotic treatment. Polyphosphate kinase 1 (PPK1) is an enzyme responsible for inorganic polyphosphate synthesis and plays a vital role in regulating various physiological processes in bacteria. In this study, we investigated the impact of polyP metabolism on the biofilm and capsule formation and virulence traits in hvKP using Dictyostelium discoideum amoeba as a model host. We found that the PPK1 null mutant was impaired in biofilm and capsule formation and showed attenuated virulence in D. discoideum compared to the wild-type strain. We performed a proteomic analysis to gain further insights into the underlying molecular mechanism. The results revealed that the PPK1 mutant had a differential expression of proteins involved in capsule synthesis (Wzi-Ugd), biofilm formation (MrkC-D-H), synthesis of the colibactin genotoxin precursor (ClbB), as well as proteins associated with the synthesis and modification of lipid A (ArnB-LpxC-PagP). These proteomic findings corroborate the phenotypic observations and indicate that the PPK1 mutation is associated with impaired biofilm and capsule formation and attenuated virulence in hvKP. Overall, our study highlights the importance of polyP synthesis in regulating extracellular biomolecules and virulence in K. pneumoniae and provides insights into potential therapeutic targets for treating K. pneumoniae infections.
Collapse
Affiliation(s)
- Diego Rojas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Andrés E Marcoleta
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Matías Gálvez-Silva
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Mauricio Díaz
- Laboratorio de Comunicación Microbiana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Mauricio Hernández
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | - Cristian Vargas
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | | | - Elard Koch
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | - Pablo Saldivia
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
- Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción CP 4070389, Chile
| | - Jorge Vielma
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Yunn-Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore CP 119077, Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore CP 119077, Singapore
| | - Nicolás Guiliani
- Laboratorio de Comunicación Microbiana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| |
Collapse
|
4
|
Wang X, Li T, Zhou L, Tu F, Rui X, Xu Z, Liu J, Cao F. Adult zebrafish infected by clinically isolated Klebsiella pneumoniae with different virulence showed increased intestinal inflammation and disturbed intestinal microbial biodiversity. BMC Infect Dis 2023; 23:899. [PMID: 38129788 PMCID: PMC10740243 DOI: 10.1186/s12879-023-08766-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/29/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Klebsiella pneumoniae is a pathogen that often infects patients in clinical practice. Due to its high virulent and drug resistance, infected patients are difficult to treat. In clinical practice, Klebsiella pneumoniae can infect patients' intestines, intestines, blood, etc., causing pathological changes. However, there is relatively little information on the impact of Klebsiella pneumoniae on intestinal inflammation and microbial populations. Zebrafish is an excellent biomedical model that has been successfully applied to the virulence assessment of Klebsiella pneumoniae. METHODS In this study, three clinically isolated representative strains of Klebsiella pneumoniae (high virulence non-resistant, high virulence resistant, and low virulence resistant) were used to infect zebrafish, and their effects on intestinal colonization, inflammation, pathology, and microbial diversity were tested. RESULTS Enzyme-linked immunoassay (ELISA) showed that Klebsiella pneumoniae significantly increased levels of the cytokines interleukin-1α (Il-1α), interleukin-1β (Il-1β), and tumor necrosis factor-α (Tnf-α), which increased inflammatory symptoms. Hematoxylin eosin staining(H&S) showed that Klebsiella pneumoniae treatment caused intestinal lesions in zebrafish, in which KP1053 exposure significantly decreased the number of goblet cells, KP1195 caused epithelial dissolution and exfoliation. In addition, Klebsiella pneumoniae disturbed the composition of intestinal microbiota, and the Shannon index increased, which increased the number of harmful bacteria. CONCLUSIONS Klebsiella pneumoniae infection can lead to intestinal colonization, inflammation, pathological changes, and changes in microbial biodiversity. This study provides a reference for the intestinal pathology of clinical Klebsiella pneumoniae infection.
Collapse
Affiliation(s)
- Xu Wang
- Department of Laboratory Medicine, Affiliated Wuxi Fifth Hospital of Jiangnan University, Wuxi, Jiangsu, 214005, China
| | - Ting Li
- Department of Laboratory Medicine, Wuxi No.8 People's Hospital, Wuxi, Jiangsu, 214005, China
| | - Lu Zhou
- Department of Laboratory Medicine, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, Jiangsu, 210009, China
| | - Fan Tu
- Department of Laboratory Medicine, Affiliated Wuxi Fifth Hospital of Jiangnan University, Wuxi, Jiangsu, 214005, China
| | - Xiaohong Rui
- Department of Laboratory Medicine, Affiliated Wuxi Fifth Hospital of Jiangnan University, Wuxi, Jiangsu, 214005, China
| | - Ze Xu
- Department of Laboratory Medicine, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, 214005, China.
| | - Jun Liu
- Department of Laboratory Medicine, Affiliated Wuxi Fifth Hospital of Jiangnan University, Wuxi, Jiangsu, 214005, China.
| | - Futao Cao
- Emergency Department, Jiangnan University Medical Center, Wuxi, Jiangsu, 214000, China.
| |
Collapse
|
5
|
Shen LF, He T, Zhuang JR, Hu XC, Rui XH, Huang J, Bao JF, Hu RJ. Evaluation of virulence of Klebsiella pneumoniae using zebrafish behavior as a biological indicator. J Infect Chemother 2023; 29:1145-1151. [PMID: 37611744 DOI: 10.1016/j.jiac.2023.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/11/2023] [Accepted: 08/20/2023] [Indexed: 08/25/2023]
Abstract
INTRODUCTION Klebsiella pneumoniae is one of the common pathogenic bacteria that can cause infections in hospitals and communities and can cause respiratory, urinary, and other multi-system infections. In recent years, the emergence of highly virulent and drug-resistant Klebsiella pneumoniae has greatly increased the difficulty of treatment for infection. Clinically, it is very important to accurately judge the virulence of isolated Klebsiella pneumoniae for treatment, but there is no better method to evaluate its virulence. METHODS In this study, zebrafish were used as a model organism, and the swimming distance was used as a detection index to identify clinically isolated Klebsiella pneumoniae. In this study, we selected two different strains of Klebsiella pneumoniae, i.e., NTUH-K2044 and ATCC BAA-1705, with known high and low virulence, respectively, to infect zebrafish juveniles and evaluated their behavioral ability according to different bacterial concentrations and different developmental times. RESULTS It was found that highly virulent Klebsiella pneumoniae caused a significant decrease in the behavioral ability of zebrafish larvae, while low-virulence Klebsiella pneumoniae had relatively little effect. CONCLUSIONS These results indicate that it is entirely feasible to assess the virulence of Klebsiella pneumoniae based on behavioral ability.
Collapse
Affiliation(s)
- Lan-Feng Shen
- Department of Laboratory Medicine, Jiangnan University Medical Center, Wuxi, 214000, Jiangsu Province, PR China
| | - Tian He
- Department of Laboratory Medicine, Affiliated Wuxi Fifth Hospital of Jiangnan University, Wuxi, 214005, Jiangsu Province, PR China
| | - Jia-Ru Zhuang
- Department of Laboratory Medicine, Jiangnan University Medical Center, Wuxi, 214000, Jiangsu Province, PR China; Wuxi School of Medicine, Jiangnan University, Wuxi, 214000, Jiangsu Province, PR China
| | - Xi-Chi Hu
- Department of Laboratory Medicine, Jiangnan University Medical Center, Wuxi, 214000, Jiangsu Province, PR China
| | - Xiao-Hong Rui
- Department of Laboratory Medicine, Affiliated Wuxi Fifth Hospital of Jiangnan University, Wuxi, 214005, Jiangsu Province, PR China
| | - Jun Huang
- Department of Laboratory Medicine, Center for Disease Control and Prevention, Xishan District, Wuxi, 214000, Jiangsu Province, PR China.
| | - Jun-Feng Bao
- Department of Laboratory Medicine, Wuxi Maternal and Child Health Care Hospital, Women's Hospital of Jiangnan University, Wuxi, 214005, Jiangsu Province, PR China.
| | - Ren-Jing Hu
- Department of Laboratory Medicine, Jiangnan University Medical Center, Wuxi, 214000, Jiangsu Province, PR China.
| |
Collapse
|
6
|
Wang Y, Su J, Zhou Z, Yang J, Liu W, Zhang Y, Zhang P, Guo T, Li G. Baicalein Resensitizes Multidrug-Resistant Gram-Negative Pathogens to Doxycycline. Microbiol Spectr 2023; 11:e0470222. [PMID: 37070985 PMCID: PMC10269726 DOI: 10.1128/spectrum.04702-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 03/31/2023] [Indexed: 04/19/2023] Open
Abstract
As multidrug-resistant pathogens emerge and spread rapidly, novel antibiotics urgently need to be discovered. With a dwindling antibiotic pipeline, antibiotic adjuvants might be used to revitalize existing antibiotics. In recent decades, traditional Chinese medicine has occupied an essential position in adjuvants of antibiotics. This study found that baicalein potentiates doxycycline against multidrug-resistant Gram-negative pathogens. Mechanism studies have shown that baicalein causes membrane disruption by attaching to phospholipids on the Gram-negative bacterial cytoplasmic membrane and lipopolysaccharides on the outer membrane. This process facilitates the entry of doxycycline into bacteria. Through collaborative strategies, baicalein can also increase the production of reactive oxygen species and inhibit the activities of multidrug efflux pumps and biofilm formation to potentiate antibiotic efficacy. Additionally, baicalein attenuates the lipopolysaccharide-induced inflammatory response in vitro. Finally, baicalein can significantly improve doxycycline efficacy in mouse lung infection models. The present study showed that baicalein might be considered a lead compound, and it should be further optimized and developed as an adjuvant that helps combat antibiotic resistance. IMPORTANCE Doxycycline is an important broad-spectrum tetracycline antibiotic used for treating multiple human infections, but its resistance rates are recently rising globally. Thus, new agents capable of boosting the effectiveness of doxycycline need to be discovered. In this study, it was found that baicalein potentiates doxycycline against multidrug-resistant Gram-negative pathogens in vitro and in vivo. Due to its low cytotoxicity and resistance, the combination of baicalein and doxycycline provides a valuable clinical reference for selecting more effective therapeutic strategies for treating infections caused by multidrug-resistant Gram-negative clinical isolates.
Collapse
Affiliation(s)
- Yuhang Wang
- Department of Microbiology, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Experimental & Translational Non-coding RNA Research, Yangzhou, People’s Republic of China
| | - Junfeng Su
- Department of Microbiology, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People’s Republic of China
| | - Ziyan Zhou
- Jiangsu Key Laboratory of Experimental & Translational Non-coding RNA Research, Yangzhou, People’s Republic of China
| | - Jie Yang
- Department of Microbiology, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Wenjuan Liu
- Laboratory Department, Affiliated Hospital of Yangzhou University, Yangzhou, People’s Republic of China
| | - Yafen Zhang
- Laboratory Department, Affiliated Hospital of Yangzhou University, Yangzhou, People’s Republic of China
| | - Pengyu Zhang
- Department of Microbiology, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Experimental & Translational Non-coding RNA Research, Yangzhou, People’s Republic of China
| | - Tingting Guo
- Department of Microbiology, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Experimental & Translational Non-coding RNA Research, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
| | - Guocai Li
- Department of Microbiology, Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Experimental & Translational Non-coding RNA Research, Yangzhou, People’s Republic of China
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, People’s Republic of China
- Laboratory Department, Affiliated Hospital of Yangzhou University, Yangzhou, People’s Republic of China
| |
Collapse
|
7
|
Duarte ELT, Rizek CF, Espinoza ES, Marchi AP, Noguera SV, Côrtes MF, Fernandes BHV, Guimarães T, de Maio Carrilho CMD, Neto LVP, Trindade PA, Costa SF. Virulomic Analysis of Multidrug-Resistant Klebsiella pneumoniae Isolates and Experimental Virulence Model Using Danio rerio (Zebrafish). Antibiotics (Basel) 2022; 11:antibiotics11111567. [PMID: 36358222 PMCID: PMC9686707 DOI: 10.3390/antibiotics11111567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
This study evaluates a possible correlation between multidrug-resistant Klebsiella pneumoniae strains and virulence markers in a Danio rerio (zebrafish) model. Whole-genome sequencing (WGS) was performed on 46 strains from three Brazilian hospitals. All of the isolates were colistin-resistant and harbored blaKPC-2. Ten different sequence types (STs) were found; 63% belonged to CC258, 22% to ST340, and 11% to ST16. The virulence factors most frequently found were type 3 fimbriae, siderophores, capsule regulators, and RND efflux-pumps. Six strains were selected for a time-kill experiment in zebrafish embryos: infection by ST16 was associated with a significantly higher mortality rate when compared to non-ST16 strains (52% vs. 29%, p = 0.002). Among the STs, the distribution of virulence factors did not differ significantly except for ST23, which harbored a greater variety of factors than other STs but was not related to a higher mortality rate in zebrafish. Although several virulence factors are described in K. pneumoniae, our study found ST16 to be the only significant predictor of a virulent phenotype in an animal model. Further research is needed to fully understand the correlation between virulence and sequence types.
Collapse
Affiliation(s)
- Edson Luiz Tarsia Duarte
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| | - Camila Fonseca Rizek
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
- Correspondence:
| | - Evelyn Sanchez Espinoza
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| | - Ana Paula Marchi
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| | - Saidy Vasconez Noguera
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| | - Marina Farrel Côrtes
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| | - Bianca H. Ventura Fernandes
- Technical Division of Teaching and Research Support—Zebrafish Unit, Faculty of Medicine of the University of São Paulo Biotherism Center, Av. Dr. Arnaldo, 455, São Paulo 01246-903, Brazil
| | - Thais Guimarães
- Hospital Infection Control Commission, Hospital das Clinicas of Faculty of Medicine, University of São Paulo (HC-FMUSP), Dr. Eneas Carvalho de Aguiar 255, São Paulo 05403-000, Brazil
| | - Claudia M. D. de Maio Carrilho
- Hospital Infection Control Commission of Londrina’s University Hospital (HU-UEL), Av. Robert Koch, 60, Londrina 86038-350, Brazil
| | - Lauro V. Perdigão Neto
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| | - Priscila A. Trindade
- Health Sciences Center, Clinical and Toxicological Analysis Department, Federal University of Santa Maria (UFSM), Av. Roraima, 1000, Prédio 26, Camobi, Santa Maria 97105-900, Brazil
| | - Silvia Figueiredo Costa
- Medical Investigation Laboratory (LIM49), Tropical Medicine Institute of University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar, 470, São Paulo 05403-000, Brazil
| |
Collapse
|
8
|
Ifrid E, Ouertatani-Sakouhi H, Jauslin T, Kicka S, Chiriano G, Harrison CF, Hilbi H, Scapozza L, Soldati T, Cosson P. 5-ethyl-2'-deoxyuridine fragilizes Klebsiella pneumoniae outer wall and facilitates intracellular killing by phagocytic cells. PLoS One 2022; 17:e0269093. [PMID: 36315510 PMCID: PMC9621411 DOI: 10.1371/journal.pone.0269093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 05/14/2022] [Indexed: 01/24/2023] Open
Abstract
Klebsiella pneumoniae is the causative agent of a variety of severe infections. Many K. pneumoniae strains are resistant to multiple antibiotics, and this situation creates a need for new antibacterial molecules. K. pneumoniae pathogenicity relies largely on its ability to escape phagocytosis and intracellular killing by phagocytic cells. Interfering with these escape mechanisms may allow to decrease bacterial virulence and to combat infections. In this study, we used Dictyostelium discoideum as a model phagocyte to screen a collection of 1,099 chemical compounds. Phg1A KO D. discoideum cells cannot feed upon K. pneumoniae bacteria, unless bacteria bear mutations decreasing their virulence. We identified 3 non-antibiotic compounds that restored growth of phg1A KO cells on K. pneumoniae, and we characterized the mode of action of one of them, 5-ethyl-2'-deoxyuridine (K2). K2-treated bacteria were more rapidly killed in D. discoideum phagosomes than non-treated bacteria. They were more sensitive to polymyxin and their outer membrane was more accessible to a hydrophobic fluorescent probe. These results suggest that K2 acts by rendering the membrane of K. pneumoniae accessible to antibacterial effectors. K2 was effective on three different K. pneumoniae strains, and acted at concentrations as low as 3 μM. K2 has previously been used to treat viral infections but its precise molecular mechanism of action in K. pneumoniae remains to be determined.
Collapse
Affiliation(s)
- Estelle Ifrid
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Hajer Ouertatani-Sakouhi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Tania Jauslin
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
| | - Sebastien Kicka
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Gianpaolo Chiriano
- Pharmaceutical Biochemistry, School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Christopher F. Harrison
- Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, Munich, Germany
| | - Hubert Hilbi
- Institute of Medical Microbiology, Department of Medicine, University of Zürich, Zürich, Switzerland
| | - Leonardo Scapozza
- Pharmaceutical Biochemistry, School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, Geneva, Switzerland
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Centre Médical Universitaire, Geneva, Switzerland
- * E-mail:
| |
Collapse
|
9
|
Sundaresan AK, Vincent K, Mohan GBM, Ramakrishnan J. Association of Sequence types, Antimicrobial Resistance and Virulence Genes in Indian isolates of Klebsiella pneumoniae: A Comparative Genomics Study. J Glob Antimicrob Resist 2022; 30:431-441. [DOI: 10.1016/j.jgar.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 10/18/2022] Open
|
10
|
Mehdizadeh M, Sheikhpour M, Salahshourifar I, Siadat SD, Saffarian P. An in Vitro Study of Molecular Effects of a Combination Treatment with Antibiotics and Nanofluid Containing Carbon Nano-tubes on Klebsiella pneumoniae. IRANIAN JOURNAL OF PUBLIC HEALTH 2022; 50:2292-2301. [PMID: 35223604 PMCID: PMC8826340 DOI: 10.18502/ijph.v50i11.7585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/09/2021] [Indexed: 11/29/2022]
Abstract
Background: We aimed to prepare a nanofluid, containing f-MWCNTs, and investigate the antibacterial efficacy of f-MWCNTs+ ciprofloxacin (cip) on Klebsiella pneumoniae by evaluating the virulence gene expression. Methods: This study was carried out from 2019 to 2020, in the Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran. The nanofluid containing antibiotic and f-MWCNTs were prepared by the ultrasonic method. The minimum inhibitory concentrations (MICs) of ciprofloxacin and f-MWCNTs were determined using the broth micro dilution MIC tests. For examining the antibacterial effects, the expression level of virulence genes, under the influence of f-MWCNTs, was evaluated by a real-time PCR. Results: The effect of 8 μg/ml ciprofloxacin + 400 μg/ml f-MWCNTs, completely inhibited the growth of the resistant isolate of K. pneumoniae, while, in the ATCC 700,603 isolate, 2 μg/ml ciprofloxacin with 100 μg/ml f-MWCNT could inhibit a bacterial growth. In the resistant K. pneumoniae clinical isolate, after f-MWCNT+cip treatment, the expression of fimA, fimD, wza, and wzi genes was significantly downregulated, compared to the ciprofloxacin treatment, and upregulated, compared to the negative control. For the ATCC 700,603 isolate treated with f-MWCNT+cip, the expression of fimA, fimD and wza virulence genes showed upregulation, compared to the negative control and downregulated in comparison with the ciprofloxacin treatment. Conclusion: Simultaneous treatment of resistant isolate of K. pneumoniae with f-MWCNTs +antibiotic could improve the effectiveness of antibiotic at lower doses, due to the reduced expression of virulence genes in comparison with antibiotic treatment, besides the increased cell wall permeability to antibiotics.
Collapse
Affiliation(s)
- Maryam Mehdizadeh
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Mojgan Sheikhpour
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran.,Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Iman Salahshourifar
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Seyed Davar Siadat
- Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran, Tehran, Iran.,Microbiology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Parvaneh Saffarian
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| |
Collapse
|
11
|
Wang Z, Ding Z, Li Z, Ding Y, Jiang F, Liu J. Antioxidant and antibacterial study of 10 flavonoids revealed rutin as a potential antibiofilm agent in Klebsiella pneumoniae strains isolated from hospitalized patients. Microb Pathog 2021; 159:105121. [PMID: 34343655 DOI: 10.1016/j.micpath.2021.105121] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 12/21/2022]
Abstract
The emergence of multidrug resistance (MDR) and extensive drug resistance (XDR) in Klebsiella pneumoniae strains has posed great threats to conventional antibiotics. Previous studies have shown that plant-derived flavonoids have inhibitory functions against pathogens. However, in K. pneumoniae, the antibacterial activity of different flavonoids against growth and biofilm formation remains a mystery. The aim of the present study was to evaluate the antioxidant abilities of different flavonoids, to screen active ingredients and to identify their inhibitory effects on K. pneumoniae growth and biofilm formation. In total, 10 flavonoids representing 4 major categories were screened and used in this study. The antioxidant capacity of each flavonoid was evaluated through a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Rutin showed the highest level of free radical scavenging capacity, followed by kaempferol, luteolin, quercetin, apigenin, hesperidin, sinensetin, naringenin, naringin and 3,5,6,7,8,3',4'-heptamethoxyflavone. The inhibitory effects of rutin and naringin on bacterial growth were also compared. The lowest MICs of rutin were found against K. pneumoniae ATCC700603 (1024 μg/mL) and E. coli ATCC25922 (512 μg/mL). However, the MBICs were not found. Rutin showed strong inhibitory ability against both the growth curve and biofilm production. The expression profiles of 15 biofilm-related genes were analyzed in biofilm cells both with and without rutin treatment. The luxS gene and wabG gene were downregulated significantly by rutin treatment. Correlation analysis showed that mrkA gene expression was positively correlated with biofilm biomass accumulation. Our study indicated that biofilm production is correlated with the expression of several genes rather than one. MrkA gene expression was positively correlated with biofilm biomass accumulation. Our study screened rutin as a potential agent to inhibit K. pneumoniae biofilm formation.
Collapse
Affiliation(s)
- Zhibin Wang
- The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, 646000, China
| | - Zixuan Ding
- The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, 646000, China
| | - Zhaoyinqian Li
- The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, 646000, China
| | - Yinhuan Ding
- The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, 646000, China
| | - Fan Jiang
- Department of Pathology and Pathophysiology, School of Basic Medicine, Shandong University, Jinan, Shandong Province, 250012, China
| | - Jinbo Liu
- The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, 646000, China.
| |
Collapse
|
12
|
Analysis of the Oxidative Stress Regulon Identifies soxS as a Genetic Target for Resistance Reversal in Multidrug-Resistant Klebsiella pneumoniae. mBio 2021; 12:e0086721. [PMID: 34098732 PMCID: PMC8262902 DOI: 10.1128/mbio.00867-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In bacteria, the defense system deployed to counter oxidative stress is orchestrated by three transcriptional factors, SoxS, SoxR, and OxyR. Although the regulon that these factors control is known in many bacteria, similar data are not available for Klebsiella pneumoniae. To address this data gap, oxidative stress was artificially induced in K. pneumoniae MGH78578 using paraquat and the corresponding oxidative stress regulon recorded using transcriptome sequencing (RNA-seq). The soxS gene was significantly induced during oxidative stress, and a knockout mutant was constructed to explore its functionality. The wild type and mutant were grown in the presence of paraquat and subjected to RNA-seq to elucidate the soxS regulon in K. pneumoniae MGH78578. Genes that are commonly regulated both in the oxidative stress and soxS regulons were identified and denoted as the oxidative SoxS regulon; these included a group of genes specifically regulated by SoxS. Efflux pump-encoding genes and global regulators were identified as part of this regulon. Consequently, the isogenic soxS mutant was found to exhibit a reduction in the minimum bactericidal concentration against tetracycline compared to that of the wild type. Impaired efflux activity, allowing tetracycline to be accumulated in the cytoplasm to bactericidal levels, was further evaluated using a tetraphenylphosphonium (TPP+) accumulation assay. The soxS mutant was also susceptible to tetracycline in vivo in a zebrafish embryo model. We conclude that the soxS gene could be considered a genetic target against which an inhibitor could be developed and used in combinatorial therapy to combat infections associated with multidrug-resistant K. pneumoniae.
Collapse
|
13
|
Assafiri O, Song AAL, Tan GH, Hanish I, Hashim AM, Yusoff K. Klebsiella virus UPM2146 lyses multiple drug-resistant Klebsiella pneumoniae in vitro and in vivo. PLoS One 2021; 16:e0245354. [PMID: 33418559 PMCID: PMC7794032 DOI: 10.1371/journal.pone.0245354] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/28/2020] [Indexed: 01/21/2023] Open
Abstract
Klebsiella pneumoniae are opportunistic bacteria found in the gut. In recent years they have been associated with nosocomial infections. The increased incidence of multiple drug-resistant K. pneumoniae makes it necessary to find new alternatives to treat the disease. In this study, phage UPM2146 was isolated from a polluted lake which can lyse its host K. pneumoniae ATCC BAA-2146. Observation from TEM shows that UPM2146 belongs to Caudoviriales (Order) based on morphological appearance. Whole genome analysis of UPM2146 showed that its genome comprises 160,795 bp encoding for 214 putative open reading frames (ORFs). Phylogenetic analysis revealed that the phage belongs to Ackermannviridae (Family) under the Caudoviriales. UPM2146 produces clear plaques with high titers of 1010 PFU/ml. The phage has an adsorption period of 4 min, latent period of 20 min, rise period of 5 min, and releases approximately 20 PFU/ bacteria at Multiplicity of Infection (MOI) of 0.001. UPM2146 has a narrow host-range and can lyse 5 out of 22 K. pneumoniae isolates (22.72%) based on spot test and efficiency of plating (EOP). The zebrafish larvae model was used to test the efficacy of UPM2146 in lysing its host. Based on colony forming unit counts, UPM2146 was able to completely lyse its host at 10 hours onwards. Moreover, we show that the phage is safe to be used in the treatment against K. pneumoniae infections in the zebrafish model.
Collapse
Affiliation(s)
- Omar Assafiri
- Faculty of Biotechnology and Biomolecular Sciences, Department of Microbiology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Adelene Ai-Lian Song
- Faculty of Biotechnology and Biomolecular Sciences, Department of Microbiology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Geok Hun Tan
- Faculty of Agriculture, Department of Agriculture Technology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Institute of Biosciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Irwan Hanish
- Faculty of Biotechnology and Biomolecular Sciences, Department of Microbiology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Amalia Mohd Hashim
- Faculty of Biotechnology and Biomolecular Sciences, Department of Microbiology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Halal Products Research Institute, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Khatijah Yusoff
- Faculty of Biotechnology and Biomolecular Sciences, Department of Microbiology, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Institute of Biosciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| |
Collapse
|
14
|
Ramos-Vivas J, Chapartegui-González I, Fernández-Martínez M, González-Rico C, Barrett J, Fortún J, Escudero R, Marco F, Linares L, Nieto J, Aranzamendi M, Muñoz P, Valerio M, Aguado JM, Chaves F, Gracia-Ahufinger I, Paez-Vega A, Martínez-Martínez L, Fariñas MC. Adherence to Human Colon Cells by Multidrug Resistant Enterobacterales Strains Isolated From Solid Organ Transplant Recipients With a Focus on Citrobacter freundii. Front Cell Infect Microbiol 2020; 10:447. [PMID: 33042855 PMCID: PMC7525035 DOI: 10.3389/fcimb.2020.00447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/21/2020] [Indexed: 12/13/2022] Open
Abstract
Enterobacteria species are common causes of hospital-acquired infections, which are associated with high morbidity and mortality rates. Immunocompromised patients such as solid organ transplant (SOT) recipients are especially at risk because they are frequently exposed to antibiotics in the course of their treatments. In this work, we used a collection of 106 Escherichia coli, 78 Klebsiella pneumoniae, 25 Enterobacter spp., and 24 Citrobacter spp. multidrug resistant strains isolated from transplant patients (hepatic, renal or renal/pancreatic) in order to examine their ability to adhere in vitro to HT-29 human colon cells, and to determine if some adhesive characteristics are associated with prevalence and persistence of these strains. A total of 33 E. coli (31%), 21 K. pneumoniae (27%), 7 Enterobacter spp. (28%), and 5 Citrobacter spp. (21%), adhered to the colon epithelial cells. Two main adherence patterns were observed in the four species analyzed, diffuse adherence, and aggregative adherence. Under transmission electronic microscopy (TEM), most bacteria lacked visible fimbria on their surface, despite their strong adherence to epithelial cells. None of the strains studied was able to induce any cytotoxic effect on HT-29 cells although some of them strongly colonizing both cells and glass coverslips at high density. Some of the strains failed to adhere to the epithelial cells but adhered strongly to the cover-slide, which shows that microscopy studies are mandatory to elucidate the adherence of bacteria to epithelial cells in vitro, and that quantitative assays using colony forming unit (CFUs) counting need to be supplemented with pictures to determine definitively if a bacterial strain adheres or not to animal cells in vitro. We report here, for the first time, the aggregative adherence pattern of two multidrug resistant (MDR) Citrobacter freundii strains isolated from human patients; importantly, biofilm formation in Citrobacter is totally dependent on the temperature; strong biofilms were formed at room temperature (RT) but not at 37°C, which can play an important role in the colonization of hospital surfaces. In conclusion, our results show that there is a great variety of adhesion phenotypes in multidrug-resistant strains that colonize transplanted patients.
Collapse
Affiliation(s)
| | | | - Marta Fernández-Martínez
- Instituto de Investigación Valdecilla-IDIVAL, Santander, Spain.,Service of Microbiology, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - Claudia González-Rico
- Instituto de Investigación Valdecilla-IDIVAL, Santander, Spain.,Service of Infectious Diseases, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - John Barrett
- Instituto de Investigación Valdecilla-IDIVAL, Santander, Spain.,New York University School of Medicine, New York, NY, United States
| | - Jesús Fortún
- Infectious Diseases Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Rosa Escudero
- Infectious Diseases Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Francesc Marco
- Service of Microbiology, Hospital Clínic-IDIBAPS, Universidad de Barcelona, Barcelona, Spain
| | - Laura Linares
- Infectious Diseases Service, Hospital Clínic-IDIBAPS, Universidad de Barcelona, Barcelona, Spain
| | - Javier Nieto
- Infectious Diseases Unit, Hospital Universitario de Cruces, Barakaldo, Spain
| | | | - Patricia Muñoz
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Maricela Valerio
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Jose María Aguado
- Infectious Diseases Unit, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Fernando Chaves
- Service of Microbiology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Irene Gracia-Ahufinger
- Microbiology Unit, Hospital Universitario Reina Sofía, Córdoba, Spain.,Maimonides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain.,Department of Microbiology, Universidad de Córdoba, Córdoba, Spain
| | - Aurora Paez-Vega
- Infectious Diseases Unit, Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Luis Martínez-Martínez
- Microbiology Unit, Hospital Universitario Reina Sofía, Córdoba, Spain.,Maimonides Biomedical Research Institute of Córdoba (IMIBIC), Córdoba, Spain.,Department of Microbiology, Universidad de Córdoba, Córdoba, Spain
| | - María Carmen Fariñas
- Instituto de Investigación Valdecilla-IDIVAL, Santander, Spain.,Service of Infectious Diseases, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| |
Collapse
|
15
|
Varas MA, Muñoz-Montecinos C, Kallens V, Simon V, Allende ML, Marcoleta AE, Lagos R. Exploiting Zebrafish Xenografts for Testing the in vivo Antitumorigenic Activity of Microcin E492 Against Human Colorectal Cancer Cells. Front Microbiol 2020; 11:405. [PMID: 32265865 PMCID: PMC7096547 DOI: 10.3389/fmicb.2020.00405] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/26/2020] [Indexed: 12/15/2022] Open
Abstract
One of the approaches to address cancer treatment is to develop new drugs not only to obtain compounds with less side effects, but also to have a broader set of alternatives to tackle the resistant forms of this pathology. In this regard, growing evidence supports the use of bacteria-derived peptides such as bacteriocins, which have emerged as promising anti-cancer molecules. In addition to test the activity of these molecules on cancer cells in culture, their in vivo antitumorigenic properties must be validated in animal models. Although the standard approach for such assays employs experiments in nude mice, at the initial stages of testing, the use of high-throughput animal models would permit rapid proof-of-concept experiments, screening a high number of compounds, and thus increasing the possibilities of finding new anti-cancer molecules. A validated and promising alternative animal model are zebrafish larvae harboring xenografts of human cancer cells. Here, we addressed the anti-cancer properties of the antibacterial peptide microcin E492 (MccE492), a bacteriocin produced by Klebsiella pneumoniae, showing that this peptide has a marked cytotoxic effect on human colorectal cancer cells in vitro. Furthermore, we developed a zebrafish xenograft model using these cells to test the antitumor effect of MccE492 in vivo, demonstrating that intratumor injection of this peptide significantly reduced the tumor cell mass. Our results provide, for the first time, evidence of the in vivo antitumoral properties of a bacteriocin tested in an animal model. This evidence strongly supports the potential of this bacteriocin for the development of novel anti-cancer therapies.
Collapse
Affiliation(s)
- Macarena A Varas
- Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Carlos Muñoz-Montecinos
- Departamento de Biología, Facultad de Ciencias, FONDAP Center for Genome Regulation, Universidad de Chile, Santiago, Chile
| | - Violeta Kallens
- Departamento de Biología, Facultad de Ciencias, FONDAP Center for Genome Regulation, Universidad de Chile, Santiago, Chile
| | - Valeska Simon
- Laboratorio de Inmunología, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Miguel L Allende
- Departamento de Biología, Facultad de Ciencias, FONDAP Center for Genome Regulation, Universidad de Chile, Santiago, Chile
| | - Andrés E Marcoleta
- Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Rosalba Lagos
- Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| |
Collapse
|
16
|
Optimisation of External Factors for the Growth of Francisella novicida within Dictyostelium discoideum. BIOMED RESEARCH INTERNATIONAL 2020; 2020:6826983. [PMID: 32090107 PMCID: PMC6996686 DOI: 10.1155/2020/6826983] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/04/2020] [Indexed: 02/06/2023]
Abstract
The amoeba Dictyostelium discoideum has been used as a model organism to study host-pathogen interaction in many intracellular bacteria. Francisella tularensis is a Gram-negative, highly infectious bacterium that causes the zoonotic disease tularemia. The bacterium is able to replicate in different phagocytic and nonphagocytic cells including mammalian, amoebae, and arthropod cells. The aim of this study was to determine the optimal temperature and infection dose in the interaction of Francisella novicida with D. discoideum in order to establish a model of Francisella infection in the social amoeba. The amoeba cells were infected with a different multiplicity of infection (5, 10, and 100) and incubated at different temperatures (22, 25, 27, 30, and 37°C). The number of intracellular bacteria within D. discoideum, as well as cytotoxicity, was determined at 2, 4, 24, 48, and 72 hours after infection. Our results showed that the optimal temperature for Francisella intracellular replication within amoeba is 30°C with the MOI of 10. We can conclude that this MOI and temperature induced the optimal growth of bacteria in Dictyostelium with low cytotoxicity.
Collapse
|
17
|
Ultrashort Cationic Lipopeptides-Effect of N-Terminal Amino Acid and Fatty Acid Type on Antimicrobial Activity and Hemolysis. Molecules 2020; 25:molecules25020257. [PMID: 31936341 PMCID: PMC7024302 DOI: 10.3390/molecules25020257] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/31/2019] [Accepted: 01/02/2020] [Indexed: 01/28/2023] Open
Abstract
Ultrashort cationic lipopeptides (USCLs) are promising antimicrobial agents that hypothetically may be alternatively used to combat pathogens such as bacteria and fungi. In general, USCLs consist of fatty acid chains and a few basic amino acid residues. The main shortcoming of USCLs is their relatively high cytotoxicity and hemolytic activity. This study focuses on the impact of the hydrophobic fatty acid chain, on both antimicrobial and hemolytic activities. To learn more about this region, a series of USCLs with different straight-chain fatty acids (C8, C10, C12, C14) attached to the tripeptide with two arginine residues were synthesized. The amino acid at the N-terminal position was exchanged for proteinogenic and non-proteinogenic amino acid residues (24 in total). Moreover, the branched fatty acid residues were conjugated to N-terminus of a dipeptide with two arginine residues. All USCLs had C-terminal amides. USCLs were tested against reference bacterial strains (including ESKAPE group) and Candida albicans. The hemolytic potential was tested on human erythrocytes. Hydrophobicity of the compounds was evaluated by RP-HPLC. Shortening of the fatty acid chain and simultaneous addition of amino acid residue at N-terminus were expected to result in more selective and active compounds than those of the reference lipopeptides with similar lipophilicity. Hypothetically, this approach would also be beneficial to other antimicrobial peptides where N-lipidation strategy was used to improve their biological characteristics.
Collapse
|
18
|
Zhang X, Zhao Y, Wu Q, Lin J, Fang R, Bi W, Dong G, Li J, Zhang Y, Cao J, Zhou T. Zebrafish and Galleria mellonella: Models to Identify the Subsequent Infection and Evaluate the Immunological Differences in Different Klebsiella pneumoniae Intestinal Colonization Strains. Front Microbiol 2019; 10:2750. [PMID: 31849893 PMCID: PMC6900958 DOI: 10.3389/fmicb.2019.02750] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/12/2019] [Indexed: 11/13/2022] Open
Abstract
The intestine is the main reservoir of bacterial pathogens in most organisms. Klebsiella pneumoniae is an important opportunistic pathogen associated with nosocomial bacterial infections. Intestinal colonization with K. pneumoniae has been shown to be associated with an increased risk of subsequent infections. However, not all K. pneumoniae strains in the intestine cause further infection, and the distinction of the difference among strains that cause infection after colonization and the ones causing only asymptomatic colonization is unclear. In this study, we report a case of a hospitalized patient from the ICU. We screened out two intestine colonization strains (FK4111, FK4758) to analyze the subsequent infection conditions. We set up infection models of zebrafish and Galleria mellonella to establish the differences in the potential for causing subsequent infection and the immunological specificities after K. pneumoniae intestine colonization. Sudan Black B and neutral red staining results indicated that FK4758 was more responsive to neutrophil recruitment and phagocytosis of macrophages than FK4111. The results of the assessment of the organ bacterial load revealed that FK4111 and FK4758 both had the highest bacterial loads in the zebrafish intestine compared to those in other organs. However, in the zebrafish spleen, liver, and heart, the FK4758 load was significantly higher than that of FK4111. The ST37 strain FK4111, which does not produce carbapenemase, did not cause infection after colonization, whereas the ST11 strain FK4758, which produces carbapenemase, caused infection after intestinal colonization. Our finding demonstrated that not all intestinal colonization of K. pneumoniae subsequently caused infections, and the infections of K. pneumoniae after colonization are different. Therefore, the infection models we established provided possibility for the estimation of host-microbial interactions.
Collapse
Affiliation(s)
- Xiucai Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yajie Zhao
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, China
| | - Qing Wu
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jie Lin
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Renchi Fang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Wenzi Bi
- Department of Clinical Laboratory, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China
| | - Guofeng Dong
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, China
| | - Jiahui Li
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yizhi Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jianming Cao
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| |
Collapse
|
19
|
Al-Farsi HM, Al-Adwani S, Ahmed S, Vogt C, Ambikan AT, Leber A, Al-Jardani A, Al-Azri S, Al-Muharmi Z, Toprak MS, Giske CG, Bergman P. Effects of the Antimicrobial Peptide LL-37 and Innate Effector Mechanisms in Colistin-Resistant Klebsiella pneumoniae With mgrB Insertions. Front Microbiol 2019; 10:2632. [PMID: 31803163 PMCID: PMC6870453 DOI: 10.3389/fmicb.2019.02632] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 10/29/2019] [Indexed: 11/14/2022] Open
Abstract
Background Colistin is a polypeptide antibiotic drug that targets lipopolysaccharides in the outer membrane of Gram-negative bacteria. Inactivation of the mgrB-gene is a common mechanism behind colistin-resistance in Klebsiella pneumoniae (Kpn). Since colistin is a cyclic polypeptide, it may exhibit cross-resistance with the antimicrobial peptide LL-37, and with other innate effector mechanisms, but previous results are inconclusive. Objective To study potential cross-resistance between colistin and LL-37, as well as with other innate effector mechanisms, and to compare virulence of colistin-resistant and susceptible Kpn strains. Materials/Methods Carbapenemase-producing Kpn from Oman (n = 17) were subjected to antimicrobial susceptibility testing and whole genome sequencing. Susceptibility to colistin and LL-37 was studied. The surface charge was determined by zeta-potential measurements and the morphology of treated bacteria was analyzed with electron microscopy. Bacterial survival was assessed in human whole blood and serum, as well as in a zebrafish infection-model. Results Genome-analysis revealed insertion-sequences in the mgrB gene, as a cause of colistin resistance in 8/17 isolates. Colistin-resistant (Col-R) isolates were found to be more resistant to LL-37 compared to colistin-susceptible (Col-S) isolates, but only at concentrations ≥50 μg/ml. There was no significant difference in surface charge between the isolates. The morphological changes were similar in both Col-R and Col-S isolates after exposure to LL-37. Finally, no survival difference between the Col-R and Col-S isolates was observed in whole blood or serum, or in zebrafish embryos. Conclusion Cross-resistance between colistin and LL-37 was observed at elevated concentrations of LL-37. However, Col-R and Col-S isolates exhibited similar survival in serum and whole blood, and in a zebrafish infection-model, suggesting that cross-resistance most likely play a limited role during physiological conditions. However, it cannot be ruled out that the observed cross-resistance could be relevant in conditions where LL-37 levels reach high concentrations, such as during infection or inflammation.
Collapse
Affiliation(s)
- Hissa M Al-Farsi
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Central Public Health Laboratories, Ministry of Health, Muscat, Oman
| | - Salma Al-Adwani
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
| | - Sultan Ahmed
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden
| | - Carmen Vogt
- Department of Applied Physics, Biomedical and X-Ray Physics, KTH Royal Institute of Technology/AlbaNova, Stockholm, Sweden
| | - Anoop T Ambikan
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden
| | - Anna Leber
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden
| | - Amina Al-Jardani
- Central Public Health Laboratories, Ministry of Health, Muscat, Oman
| | - Saleh Al-Azri
- Central Public Health Laboratories, Ministry of Health, Muscat, Oman
| | - Zakariya Al-Muharmi
- Department of Microbiology & Immunology, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Muhammet S Toprak
- Department of Applied Physics, Biomedical and X-Ray Physics, KTH Royal Institute of Technology/AlbaNova, Stockholm, Sweden
| | - Christian G Giske
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Peter Bergman
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Infectious Disease Clinic, The Immunodeficiency Unit, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
20
|
Bengoechea JA, Sa Pessoa J. Klebsiella pneumoniae infection biology: living to counteract host defences. FEMS Microbiol Rev 2019; 43:123-144. [PMID: 30452654 PMCID: PMC6435446 DOI: 10.1093/femsre/fuy043] [Citation(s) in RCA: 265] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/16/2018] [Indexed: 12/26/2022] Open
Abstract
Klebsiella species cause a wide range of diseases including pneumonia, urinary tract infections (UTIs), bloodstream infections and sepsis. These infections are particularly a problem among neonates, elderly and immunocompromised individuals. Klebsiella is also responsible for a significant number of community-acquired infections. A defining feature of these infections is their morbidity and mortality, and the Klebsiella strains associated with them are considered hypervirulent. The increasing isolation of multidrug-resistant strains has significantly narrowed, or in some settings completely removed, the therapeutic options for the treatment of Klebsiella infections. Not surprisingly, this pathogen has then been singled out as an 'urgent threat to human health' by several organisations. This review summarises the tremendous progress that has been made to uncover the sophisticated immune evasion strategies of K. pneumoniae. The co-evolution of Klebsiella in response to the challenge of an activated immune has made Klebsiella a formidable pathogen exploiting stealth strategies and actively suppressing innate immune defences to overcome host responses to survive in the tissues. A better understanding of Klebsiella immune evasion strategies in the context of the host-pathogen interactions is pivotal to develop new therapeutics, which can be based on antagonising the anti-immune strategies of this pathogen.
Collapse
Affiliation(s)
- José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Joana Sa Pessoa
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| |
Collapse
|
21
|
Urrutia ÍM, Sabag A, Valenzuela C, Labra B, Álvarez SA, Santiviago CA. Contribution of the Twin-Arginine Translocation System to the Intracellular Survival of Salmonella Typhimurium in Dictyostelium discoideum. Front Microbiol 2018; 9:3001. [PMID: 30574134 PMCID: PMC6291500 DOI: 10.3389/fmicb.2018.03001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 11/20/2018] [Indexed: 12/19/2022] Open
Abstract
The twin-arginine translocation (Tat) system is a specialized secretion pathway required for bacteria to export fully folded proteins through the cytoplasmic membrane. This system is crucial during Salmonella infection of animal hosts. In this study, we show that Salmonella enterica serovar Typhimurium (S. Typhimurium) requires the Tat system to survive and proliferate intracellularly in the social amoeba Dictyostelium discoideum. To achieve this, we developed a new infection assay to assess intracellular bacterial loads in amoeba by direct enumeration of colony forming units (CFU) at different times of infection. Using this assay we observed that a ΔtatABC mutant was internalized in higher numbers than the wild type, and was defective for intracellular survival in the amoeba at all times post infection evaluated. In addition, we assessed the effect of the ΔtatABC mutant in the social development of D. discoideum. In contrast to the wild-type strain, we observed that the mutant was unable to delay the social development of the amoeba at 2 days of co-incubation. This phenotype correlated with defects in intracellular proliferation presented by the ΔtatABC mutant in D. discoideum after 24 h of infection. All phenotypes described for the mutant were reverted by the presence of a plasmid carrying tatABC genes, indicating that abrogation of Tat system attenuates S. Typhimurium in this model organism. Overall, our results indicate that the Tat system is crucial for S. Typhimurium to survive and proliferate intracellularly in D. discoideum and for virulence in this host. To the best of our knowledge, this is the first report on the relevance of the Tat system in the interaction of any bacterial pathogen with the social amoeba D. discoideum.
Collapse
Affiliation(s)
- Ítalo M Urrutia
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Andrea Sabag
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Camila Valenzuela
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Bayron Labra
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Sergio A Álvarez
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Carlos A Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| |
Collapse
|
22
|
Marcoleta AE, Gutiérrez-Cortez S, Hurtado F, Argandoña Y, Corsini G, Monasterio O, Lagos R. The Ferric uptake regulator (Fur) and iron availability control the production and maturation of the antibacterial peptide microcin E492. PLoS One 2018; 13:e0200835. [PMID: 30071030 PMCID: PMC6071977 DOI: 10.1371/journal.pone.0200835] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 05/22/2018] [Indexed: 01/10/2023] Open
Abstract
Microcin E492 is a pore-forming bacteriocin with toxic activity against Enterobacteriaceae, which undergoes amyloid aggregation as a mechanism to regulate its toxicity. To be active, it requires the posttranslational attachment to the C-terminus of a glycosylated enterochelin derivative (salmochelin), a process carried out by the proteins MceC, MceI and MceJ encoded in the MccE492 gene cluster. Both microcin E492 and salmochelin have a proposed role in the virulence of the bacterial pathogen Klebsiella pneumoniae. Besides, enterochelin is produced as a response to low iron availability and its synthesis is controlled by the global iron regulator Fur. Since the production of active microcin E492 depends on enterochelin biosynthesis, both processes could be coordinately regulated. In this work, we investigated the role of Fur in the expression of the microcin E492 maturation genes mceCJI. mceC was not regulated by Fur as it occurs with its homolog iroB in Salmonella enterica. We demonstrated that mceJI along with the previously uncharacterized gene mceX are transcribed as a single mRNA, and that Fur binds in vivo to a Fur box located upstream of the mceX-mceJI unit. Also, we established that the expression of these genes decreased in a condition of high iron availability, while this effect is abrogated in a Δfur background. Furthermore, our results indicated that MceX acts as a negative regulator of microcin E492 structural gene expression, coupling its synthesis to the iron-dependent regulatory circuit. Consequently, fur or mceX overexpression led to a significant decrease in the antibacterial activity of cells producing microcin E492. Altogether these results show that both the expression of microcin E492 maturation genes mceJI, and MceX the negative regulator of microcin E492 synthesis, are coordinated with the enterochelin production by Fur, depending on the iron levels in the medium.
Collapse
Affiliation(s)
- Andrés E. Marcoleta
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
- * E-mail: (RL); (AEM)
| | - Sergio Gutiérrez-Cortez
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
| | - Felipe Hurtado
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
| | - Yerko Argandoña
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
| | - Gino Corsini
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
| | - Octavio Monasterio
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
| | - Rosalba Lagos
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Casilla, Santiago, Chile
- * E-mail: (RL); (AEM)
| |
Collapse
|