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Su S, Li Z, Sun Y, Gao S, Gao Q. The multifaceted role of TolA protein in promoting survival, biofilm formation and virulence of avian pathogenic Escherichia coli. Poult Sci 2024; 103:104142. [PMID: 39106694 DOI: 10.1016/j.psj.2024.104142] [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: 05/06/2024] [Revised: 06/26/2024] [Accepted: 07/25/2024] [Indexed: 08/09/2024] Open
Abstract
Avian pathogenic Escherichia coli (APEC) can spread beyond the intestines and cause systemic infections, leading to various clinical manifestations, including airsacculitis, pericarditis, perihepatitis and colisepticemia. The mechanisms facilitating this extraintestinal infections are not fully understood. In this study, we investigate how the tolA gene affects APEC virulence by encoding a protein involved in maintaining outer membrane integrity. We constructed a tolA deletion mutant of APEC strain E058 and evaluated its growth and survival in various environments, including in vitro cultures and in vivo infection models in chickens. We found that the motility-defective ΔtolA mutant exhibits reduced biofilm formation ability and weakened resistance to the environmental stresses, suggesting an important role for TolA in APEC's survival. The lack of tolA gene affects the bacterial ability to resist the host's immune system, such as complement-mediated serum killing or phagocytosis, as shown by the serum killing and macrophage phagocytosis assays. Additionally, in vivo infection studies using chickens demonstrated that the ΔtolA mutant displayed attenuated virulence, evidenced by reduced mortality and lower tissue bacterial burden. Reverse transcription quantitative real-time PCR (RT-qPCR) analysis revealed that inactivation of tolA led to downregulation of virulence genes associated with serum resistance (traT) and flagellar biosynthesis (fliR). Taken together, our findings demonstrate the multifaceted role of TolA protein in promoting the survival, immune evasion, biofilm formation, and virulence of APEC E058. This suggests that targeting TolA could potentially offer new strategies for combating APEC infections.
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Affiliation(s)
- Senyan Su
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China; Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Zhengliang Li
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China; Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Yunyan Sun
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China; Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Song Gao
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China; Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China
| | - Qingqing Gao
- Institute of Agricultural Science and Technology Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China; Key Laboratory of Avian Bioproduct Development, Ministry of Agriculture and Rural Affairs, Yangzhou, China; Institutes of Agricultural Science and Technology Development, Yangzhou University, Yangzhou, China.
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2
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Andima M, Boese A, Paul P, Koch M, Loretz B, Lehr CM. Targeting Intracellular Bacteria with Dual Drug-loaded Lactoferrin Nanoparticles. ACS Infect Dis 2024; 10:1696-1710. [PMID: 38577780 PMCID: PMC11091908 DOI: 10.1021/acsinfecdis.4c00045] [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: 01/16/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
Treatment of microbial infections is becoming daunting because of widespread antimicrobial resistance. The treatment challenge is further exacerbated by the fact that certain infectious bacteria invade and localize within host cells, protecting the bacteria from antimicrobial treatments and the host's immune response. To survive in the intracellular niche, such bacteria deploy surface receptors similar to host cell receptors to sequester iron, an essential nutrient for their virulence, from host iron-binding proteins, in particular lactoferrin and transferrin. In this context, we aimed to target lactoferrin receptors expressed by macrophages and bacteria; as such, we prepared and characterized lactoferrin nanoparticles (Lf-NPs) loaded with a dual drug combination of antimicrobial natural alkaloids, berberine or sanguinarine, with vancomycin or imipenem. We observed increased uptake of drug-loaded Lf-NPs by differentiated THP-1 cells with up to 90% proportion of fluorescent cells, which decreased to about 60% in the presence of free lactoferrin, demonstrating the targeting ability of Lf-NPs. The encapsulated antibiotic drug cocktail efficiently cleared intracellular Staphylococcus aureus (Newman strain) compared to the free drug combinations. However, the encapsulated drugs and the free drugs alike exhibited a bacteriostatic effect against the hard-to-treat Mycobacterium abscessus (smooth variant). In conclusion, the results of this study demonstrate the potential of lactoferrin nanoparticles for the targeted delivery of antibiotic drug cocktails for the treatment of intracellular bacteria.
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Affiliation(s)
- Moses Andima
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
- Department
of Chemistry, Faculty of Science and Education, Busitema University, P.O Box 236, Tororo 21435, Uganda
| | - Annette Boese
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
| | - Pascal Paul
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
| | - Marcus Koch
- INM-Leibniz
Institute for New Materials, Campus D2 2, Saarbrücken 66123, Germany
| | - Brigitta Loretz
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
| | - Claus-Micheal Lehr
- Department
of Drug Delivery (DDEL), Helmholtz Institute
for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for
Infection Research, Campus E8.1, Saarbrücken 66123, Germany
- Department
of Pharmacy, Saarland University, Saarbrücken 66123, Germany
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3
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Schulze-Luehrmann J, Liebler-Tenorio E, Felipe-López A, Lührmann A. Cell death induction facilitates egress of Coxiella burnetii from infected host cells at late stages of infection. Mol Microbiol 2024; 121:513-528. [PMID: 38115201 DOI: 10.1111/mmi.15210] [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: 03/09/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023]
Abstract
Intracellular bacteria have evolved mechanisms to invade host cells, establish an intracellular niche that allows survival and replication, produce progeny, and exit the host cell after completion of the replication cycle to infect new target cells. Bacteria exit their host cell by (i) initiation of apoptosis, (ii) lytic cell death, and (iii) exocytosis. While bacterial egress is essential for bacterial spreading and, thus, pathogenesis, we currently lack information about egress mechanisms for the obligate intracellular pathogen C. burnetii, the causative agent of the zoonosis Q fever. Here, we demonstrate that C. burnetii inhibits host cell apoptosis early during infection, but induces and/or increases apoptosis at later stages of infection. Only at later stages of infection did we observe C. burnetii egress, which depends on previously established large bacteria-filled vacuoles and a functional intrinsic apoptotic cascade. The released bacteria are not enclosed by a host cell membrane and can infect and replicate in new target cells. In summary, our data argue that C. burnetii egress in a non-synchronous way at late stages of infection. Apoptosis-induction is important for C. burnetii egress, but other pathways most likely contribute.
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Affiliation(s)
- Jan Schulze-Luehrmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Alfonso Felipe-López
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Anja Lührmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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4
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Toniolo C, Sage D, McKinney JD, Dhar N. Quantification of Mycobacterium tuberculosis Growth in Cell-Based Infection Assays by Time-Lapse Fluorescence Microscopy. Methods Mol Biol 2024; 2813:167-188. [PMID: 38888778 DOI: 10.1007/978-1-0716-3890-3_12] [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: 06/20/2024]
Abstract
Quantification of Mycobacterium tuberculosis (Mtb) growth dynamics in cell-based in vitro infection models is traditionally carried out by measurement of colony forming units (CFU). However, Mtb being an extremely slow growing organism (16-24 h doubling time), this approach requires at least 3 weeks of incubation to obtain measurable readouts. In this chapter, we describe an alternative approach based on time-lapse microscopy and quantitative image analysis that allows faster quantification of Mtb growth dynamics in host cells. In addition, this approach provides the capability to capture other readouts from the same experimental setup, such as host cell viability, bacterial localization as well as the dynamics of propagation of infection between the host cells.
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Affiliation(s)
- Chiara Toniolo
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Daniel Sage
- Biomedical Imaging Group, School of Engineering, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - John D McKinney
- School of Life Sciences, Swiss Federal Institute of Technology in Lausanne (EPFL), Lausanne, Switzerland
| | - Neeraj Dhar
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada.
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada.
- School of Public Health, University of Saskatchewan, Saskatoon, SK, Canada.
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5
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Wang KC, Jensen PR. Metabolic Analysis of Intracellular Pathogenic Bacteria Using NMR. Methods Mol Biol 2024; 2813:95-105. [PMID: 38888772 DOI: 10.1007/978-1-0716-3890-3_6] [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: 06/20/2024]
Abstract
Pathogen proliferation and virulence depend on available nutrients, and these vary when the pathogen moves from outside of the host cell (extracellular) to the inside of the host cell (intracellular). Nuclear Magnetic Resonance (NMR) is a versatile analytical method, which lends itself for metabolic studies. In this chapter, we describe how 1H NMR can be combined with a cellular infection model to study the metabolic crosstalk between a bacterial pathogen and its host both in the extracellular and intracellular compartments. Central carbon metabolism is highlighted by using glucose labeled with the stable isotope 13C.
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Affiliation(s)
- Ke-Chuan Wang
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
| | - Pernille Rose Jensen
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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6
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Lee EB, Lee K. A Pharmacodynamic Study of Aminoglycosides against Pathogenic E. coli through Monte Carlo Simulation. Pharmaceuticals (Basel) 2023; 17:27. [PMID: 38256861 PMCID: PMC10819079 DOI: 10.3390/ph17010027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/24/2024] Open
Abstract
This research focuses on combating the increasing problem of antimicrobial resistance, especially in Escherichia coli (E. coli), by assessing the efficacy of aminoglycosides. The study specifically addresses the challenge of developing new therapeutic approaches by integrating experimental data with mathematical modeling to better understand the action of aminoglycosides. It involves testing various antibiotics like streptomycin (SMN), kanamycin (KMN), gentamicin (GMN), tobramycin (TMN), and amikacin (AKN) against the O157:H7 strain of E. coli. The study employs a pharmacodynamics (PD) model to analyze how different antibiotic concentrations affect bacterial growth, utilizing minimum inhibitory concentration (MIC) to gauge the effective bactericidal levels of the antibiotics. The study's approach involved transforming bacterial growth rates, as obtained from time-kill curve data, into logarithmic values. A model was then developed to correlate these log-transformed values with their respective responses. To generate additional data points, each value was systematically increased by an increment of 0.1. To simulate real-world variability and randomness in the data, a Gaussian scatter model, characterized by parameters like κ and EC50, was employed. The mathematical modeling was pivotal in uncovering the bactericidal properties of these antibiotics, indicating different PD MIC (zMIC) values for each (SMN: 1.22; KMN: 0.89; GMN: 0.21; TMN: 0.32; AKN: 0.13), which aligned with MIC values obtained through microdilution methods. This innovative blend of experimental and mathematical approaches in the study marks a significant advancement in formulating strategies to combat the growing threat of antimicrobial-resistant E. coli, offering a novel pathway to understand and tackle antimicrobial resistance more effectively.
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Affiliation(s)
- Eon-Bee Lee
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Republic of Korea;
| | - Kyubae Lee
- Department of Medical Engineering, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul 03722, Republic of Korea
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Wang KC, Lerche MH, Ardenkjær-Larsen JH, Jensen PR. Formate Metabolism in Shigella flexneri and Its Effect on HeLa Cells at Different Stages during the Infectious Process. Microbiol Spectr 2023; 11:e0063122. [PMID: 37042762 PMCID: PMC10269805 DOI: 10.1128/spectrum.00631-22] [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: 03/25/2022] [Accepted: 03/16/2023] [Indexed: 04/13/2023] Open
Abstract
Shigellosis caused by Shigella is one of the most important foodborne illnesses in global health, but little is known about the metabolic cross talk between this bacterial pathogen and its host cells during the different stages of the infection process. A detailed understanding of the metabolism can potentially lead to new drug targets remedying the pressing problem of antibiotic resistance. Here, we use stable isotope-resolved metabolomics as an unbiased and fast method to investigate how Shigella metabolizes 13C-glucose in three different environments: inside the host cells, adhering to the host cells, and alone in suspension. We find that especially formate metabolism by bacteria is sensitive to these different environments. The role of formate in pathogen metabolism is sparsely described in the literature compared to the roles of acetate and butyrate. However, its metabolic pathway is regarded as a potential drug target due to its production in microorganisms and its absence in humans. Our study provides new knowledge about the regulatory effect of formate. Bacterial metabolism of formate is pH dependent when studied alone in culture medium, whereas this effect is less pronounced when the bacteria adhere to the host cells. Once the bacteria are inside the host cells, we find that formate accumulation is reduced. Formate also affects the host cells resulting in a reduced infection rate. This was correlated to an increased immune response. Thus, intriguingly formate plays a double role in pathogenesis by increasing the virulence of Shigella and at the same time stimulating the immune response of the host. IMPORTANCE Bacterial infection is a pressing societal concern due to development of resistance toward known antibiotics. Central carbon metabolism has been suggested as a potential new target for drug development, but metabolic changes upon infection remain incompletely understood. Here, we used a cellular infection model to study how the bacterial pathogen Shigella adapts its metabolism depending on the environment starting from the extracellular medium until Shigella successfully invaded and proliferated inside host cells. The mixed-acid fermentation of Shigella was the major metabolic pathway during the infectious process, and the glucose-derived metabolite formate surprisingly played a divergent role in the pathogen and in the host cell. Our data show reduced infection rate when both host cells and bacteria were treated with formate, which correlated with an upregulated immune response in the host cells. The formate metabolism in Shigella thus potentially provides a route toward alternative treatment strategies for Shigella prevention.
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Affiliation(s)
- Ke-Chuan Wang
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Mathilde Hauge Lerche
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Jan Henrik Ardenkjær-Larsen
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Pernille Rose Jensen
- Center for Hyperpolarization in Magnetic Resonance, Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
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8
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Tong Y, Lu G, Wang Z, Hao S, Zhang G, Sun H. Tubeimuside I improves the efficacy of a therapeutic Fusobacterium nucleatum dendritic cell-based vaccine against colorectal cancer. Front Immunol 2023; 14:1154818. [PMID: 37207216 PMCID: PMC10189021 DOI: 10.3389/fimmu.2023.1154818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/24/2023] [Indexed: 05/21/2023] Open
Abstract
Introduction Fusobacterium nucleatum (F. nucleatum) infection has been confirmed to be associated with the development, chemoresistance, and immune evasion of colorectal cancer (CRC). The complex relationship between the microorganism, host cells, and the immune system throughout all stages of CRC progression, which makes the development of new therapeutic methods difficult. Methods We developed a new dendritic cell (DC) vaccine to investigate the antitumor efficacy of CRC immunotherapy strategies. By mediating a specific mode of interaction between the bacteria, tumor, and host, we found a new plant-derived adjuvant, tubeimuside I (TBI), which simultaneously improved the DC vaccine efficacy and inhibited the F. nucleatum infection. Encapsulating TBI in a nanoemulsion greatly improved the drug efficacy and reduced the drug dosage and administration times. Results The nanoemulsion encapsulated TBI DC vaccine exhibited an excellent antibacterial and antitumor effect and improved the survival rate of CRC mice by inhibiting tumor development and progression. Discussion In this study, we provide a effective strategy for developing a DC-based vaccine against CRC and underlies the importance of further understanding the mechanism of CRC processes caused by F. nucleatum.
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Affiliation(s)
- Yanan Tong
- Department of Nuclear Medicine, General Hospital of Northern Theater Command, Shenyang, China
| | - Guoxiu Lu
- Department of Nuclear Medicine, General Hospital of Northern Theater Command, Shenyang, China
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, Liaoning, China
| | - Zhiguo Wang
- Department of Nuclear Medicine, General Hospital of Northern Theater Command, Shenyang, China
| | - Shanhu Hao
- Department of Nuclear Medicine, General Hospital of Northern Theater Command, Shenyang, China
| | - Guoxu Zhang
- Department of Nuclear Medicine, General Hospital of Northern Theater Command, Shenyang, China
- *Correspondence: Guoxu Zhang, ; Hongwu Sun,
| | - Hongwu Sun
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
- *Correspondence: Guoxu Zhang, ; Hongwu Sun,
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Intraoperative Gentamicin Intravesical Instillation for Prevention of Urinary Tract Infection After Urogynecologic Surgery: A Randomized Controlled Trial. UROGYNECOLOGY (HAGERSTOWN, MD.) 2022; 28:825-833. [PMID: 36409639 DOI: 10.1097/spv.0000000000001233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
IMPORTANCE Currently available evidence for efficacy of postoperative antibiotics to prevent postoperative urinary tract infection (UTI) conflicts. Oral antibiotics rely on patient adherence and can cause unwanted systemic effects. Gentamicin is a broad-spectrum antibiotic with rapid bactericidal activity and, when administered intravesically, has no systemic absorption through intact urothelium. OBJECTIVE We aimed to determine whether a single intravesical instillation of gentamicin at the conclusion of urogynecologic surgery would reduce the proportion of women treated for UTI within 6 weeks postoperatively compared with sham instillation. STUDY DESIGN This was a multicenter, randomized (stratified by study site, route of prolapse repair ±suburethral sling, with balanced 1:1 randomization), participant-masked, sham-controlled, study. The primary outcome was the proportion of participants treated with antibiotics for UTI within 6 weeks postoperatively. An adjusted multivariable logistic regression model was constructed to determine predictors of postoperative UTI treatment. RESULTS Three hundred seventy participants were randomized (gentamicin, 185; sham, 185), and data from 363 participants were analyzed (gentamicin, 183; sham, 180). Nineteen women in the gentamicin group and 20 women in the sham group were treated for UTI within 6 weeks postoperatively (10.4% vs 11.1%, P = 0.87). There were no adverse events related to the instillations. Increasing age (odds ratio, 1.028 [1.000-1.057]) and number of intraoperative transurethral instrumentations (odds ratio, 1.342 [1.080-1.668]) were independent predictors of postoperative UTI treatment. CONCLUSIONS In women undergoing urogynecologic surgery, postoperative intravesical gentamicin did not reduce the incidence of postoperative UTI. The number of intraoperative transurethral instrumentations is an important, potentially modifiable risk factor for postoperative UTI treatment.
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A Model of Intracellular Persistence of Pseudomonas aeruginosa in Airway Epithelial Cells. Cell Microbiol 2022. [DOI: 10.1155/2022/5431666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pseudomonas aeruginosa (P.a.) is a major human pathogen capable of causing chronic infections in hosts with weakened barrier functions and host defenses, most notably airway infections commonly observed in individuals with the genetic disorder cystic fibrosis (CF). While mainly described as an extracellular pathogen, previous in vitro studies have described the molecular events leading to P.a. internalization in diverse epithelial cell types. However, the long-term fate of intracellular P.a. remains largely unknown. Here, we developed a model allowing for a better understanding of long-term (up to 120 h) intracellular bacterial survival in the airway epithelial cell line BEAS-2B. Using a tobramycin protection assay, we characterized the internalization, long-term intracellular survival, and cytotoxicity of the lab strain PAO1, as well as clinical CF isolates, and conducted analyses at the single-cell level using confocal microscopy and flow cytometry techniques. We observed that infection at low multiplicity of infection allows for intracellular survival up to 120 h post-infection without causing significant host cytotoxicity. Finally, infection with clinical isolates revealed significant strain-to-strain heterogeneity in intracellular survival, including a high persistence phenotype associated with bacterial replication within host cells. Future studies using this model will further elucidate the host and bacterial mechanisms that promote P. aeruginosa intracellular persistence in airway epithelial cells, a potentially unrecognized bacterial reservoir during chronic infections.
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11
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LuTheryn G, Hind C, Campbell C, Crowther A, Wu Q, Keller SB, Glynne-Jones P, Sutton JM, Webb JS, Gray M, Wilks SA, Stride E, Carugo D. Bactericidal and anti-biofilm effects of uncharged and cationic ultrasound-responsive nitric oxide microbubbles on Pseudomonas aeruginosa biofilms. Front Cell Infect Microbiol 2022; 12:956808. [PMID: 35992170 PMCID: PMC9386126 DOI: 10.3389/fcimb.2022.956808] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/14/2022] [Indexed: 11/25/2022] Open
Abstract
Bacterial biofilms are a major and ongoing concern for public health, featuring both inherited genetic resistance traits and a conferred innate tolerance to traditional antibiotic therapies. Consequently, there is a growing need for novel methods of drug delivery, to increase the efficacy of antimicrobial agents. This research evaluated the anti-biofilm and bactericidal effects of ultrasound responsive gas-microbubbles (MBs) of either air or nitric oxide, using an in vitro Pseudomonas aeruginosa biofilm model grown in artificial wound medium. The four lipid-based MB formulations evaluated were room-air MBs (RAMBs) and nitric oxide MBs (NOMBs) with no electrical charge, as well as cationic (+) RAMBs+ and NOMBs+. Two principal treatment conditions were used: i) ultrasound stimulated MBs only, and ii) ultrasound stimulated MBs with a sub-inhibitory concentration (4 µg/mL) of the antibiotic gentamicin. The total treatment time was divided into a 60 second passive MB interaction period prior to 40 second ultrasound exposure; each MB formulation was tested in triplicate. Ultrasound stimulated RAMBs and NOMBs without antibiotic achieved reductions in biofilm biomass of 93.3% and 94.0%, respectively. Their bactericidal efficacy however was limited, with a reduction in culturable cells of 26.9% and 65.3%, respectively. NOMBs with sub-inhibitory antibiotic produced the most significant reduction in biofilm biomass, corresponding to a 99.9% (SD ± 5.21%); and a 99.9% (SD ± 0.07%) (3-log) reduction in culturable bacterial cells. Cationic MBs were initially manufactured to promote binding of MBs to negatively charged biofilms, but these formulations also demonstrated intrinsic bactericidal properties. In the absence of antibiotic, the bactericidal efficacy of RAMB+ and NOMB+ was greater that of uncharged counterparts, reducing culturable cells by 84.7% and 86.1% respectively; increasing to 99.8% when combined with antibiotic. This study thus demonstrates the anti-biofilm and bactericidal utility of ultrasound stimulated MBs, and specifically is the first to demonstrate the efficacy of a NOMB for the dispersal and potentiation of antibiotics against bacterial biofilms in vitro. Importantly the biofilm system and complex growth-medium were selected to recapitulate key morphological features of in vivo biofilms. The results us offer new insight for the development of new clinical treatments, for example, in chronic wounds.
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Affiliation(s)
- Gareth LuTheryn
- University College London (UCL) School of Pharmacy, Department of Pharmaceutics, University College London, London, United Kingdom
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
- *Correspondence: Gareth LuTheryn, ; ; Dario Carugo, ;
| | - Charlotte Hind
- Healthcare Biotechnology, United Kingdom Health Security Agency (UKHSA), Porton Down, Salisbury, United Kingdom
| | - Christopher Campbell
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - Aaron Crowther
- University College London (UCL) School of Pharmacy, Department of Pharmaceutics, University College London, London, United Kingdom
| | - Qiang Wu
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Sara B. Keller
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Peter Glynne-Jones
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - J. Mark Sutton
- Healthcare Biotechnology, United Kingdom Health Security Agency (UKHSA), Porton Down, Salisbury, United Kingdom
| | - Jeremy S. Webb
- School of Biological Sciences, Faculty of Environmental and Life Sciences, National Biofilms Innovation Centre (NBIC) and Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Michael Gray
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Sandra A. Wilks
- School of Health Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Eleanor Stride
- Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom
| | - Dario Carugo
- University College London (UCL) School of Pharmacy, Department of Pharmaceutics, University College London, London, United Kingdom
- *Correspondence: Gareth LuTheryn, ; ; Dario Carugo, ;
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12
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Onorini D, Borel N, Schoborg RV, Leonard CA. Neisseria gonorrhoeae Limits Chlamydia trachomatis Inclusion Development and Infectivity in a Novel In Vitro Co-Infection Model. Front Cell Infect Microbiol 2022; 12:911818. [PMID: 35873141 PMCID: PMC9300984 DOI: 10.3389/fcimb.2022.911818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng) are the most common bacterial sexually transmitted infections (STIs) worldwide. The primary site of infection for both bacteria is the epithelium of the endocervix in women and the urethra in men; both can also infect the rectum, pharynx and conjunctiva. Ct/Ng co-infections are more common than expected by chance, suggesting Ct/Ng interactions increase susceptibility and/or transmissibility. To date, studies have largely focused on each pathogen individually and models exploring co-infection are limited. We aimed to determine if Ng co-infection influences chlamydial infection and development and we hypothesized that Ng-infected cells are more susceptible to chlamydial infection than uninfected cells. To address this hypothesis, we established an in vitro model of Ct/Ng co-infection in cultured human cervical epithelial cells. Our data show that Ng co-infection elicits an anti-chlamydial effect by reducing chlamydial infection, inclusion size, and subsequent infectivity. Notably, the anti-chlamydial effect is dependent on Ng viability but not extracellular nutrient depletion or pH modulation. Though this finding is not consistent with our hypothesis, it provides evidence that interaction of these bacteria in vitro influences chlamydial infection and development. This Ct/Ng co-infection model, established in an epithelial cell line, will facilitate further exploration into the pathogenic interplay between Ct and Ng.
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Affiliation(s)
- Delia Onorini
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Nicole Borel
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Robert V. Schoborg
- Department of Medical Education, Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Cory Ann Leonard
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- *Correspondence: Cory Ann Leonard,
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Nunez N, Derré-Bobillot A, Trainel N, Lakisic G, Lecomte A, Mercier-Nomé F, Cassard AM, Bierne H, Serror P, Archambaud C. The unforeseen intracellular lifestyle of Enterococcus faecalis in hepatocytes. Gut Microbes 2022; 14:2058851. [PMID: 35373699 PMCID: PMC8986240 DOI: 10.1080/19490976.2022.2058851] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enterococcus faecalis is a bacterial species present at a subdominant level in the human gut microbiota. This commensal turns into an opportunistic pathogen under specific conditions involving dysbiosis and host immune deficiency. E. faecalis is one of the rare pathobionts identified to date as contributing to liver damage in alcoholic liver disease. We have previously observed that E. faecalis is internalized in hepatocytes. Here, the survival and fate of E. faecalis was examined in hepatocytes, the main epithelial cell type in the liver. Although referred to as an extracellular pathogen, we demonstrate that E. faecalis is able to survive and divide in hepatocytes, and form intracellular clusters in two distinct hepatocyte cell lines, in primary mouse hepatocytes, as well as in vivo. This novel process extends to kidney cells. Unraveling the intracellular lifestyle of E. faecalis, our findings contribute to the understanding of pathobiont-driven diseases.
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Affiliation(s)
- Natalia Nunez
- Université -Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | | | - Nicolas Trainel
- Université Paris-Saclay, Inserm U996, Inflammation, Microbiome and Immunosurveillance, Clamart, France
| | - Goran Lakisic
- Université -Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Alexandre Lecomte
- Université -Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Françoise Mercier-Nomé
- Université Paris-Saclay, INSERM, CNRS, Institut Paris Saclay d’Innovation Thérapeutique, Châtenay-Malabry, France
| | - Anne-Marie Cassard
- Université Paris-Saclay, Inserm U996, Inflammation, Microbiome and Immunosurveillance, Clamart, France
| | - Hélène Bierne
- Université -Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Pascale Serror
- Université -Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France,CONTACT Pascale Serror Université Paris-Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Cristel Archambaud
- Université -Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France,Cristel Archambaud Université Paris-Saclay, Inrae, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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14
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Akinsola RO, Adewoyin M, Lee CW, Sim EUH, Narayanan K. RFP-based method for real-time tracking of invasive bacteria in a heterogeneous population of cells. Anal Biochem 2021; 634:114432. [PMID: 34695391 DOI: 10.1016/j.ab.2021.114432] [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] [Received: 04/13/2021] [Revised: 09/02/2021] [Accepted: 10/19/2021] [Indexed: 10/20/2022]
Abstract
Quantification of bacterial invasion into eukaryotic cells is a prerequisite to unfold the molecular mechanisms of this vector's function to obtain insights for improving its efficiency. Invasion is traditionally quantified by antibiotic protection assays that require dilution plating and counting of colony-forming units rescued from infected cells. However, to differentiate between attached and internalized bacteria vector, this assay requires supplementation by a time-consuming and tedious immunofluorescence staining, making it laborious and reduces its reliability and reproducibility. Here we describe a new red fluorescent protein (RFP)-based high-throughput and inexpensive method for tracking bacterial adherence and internalization through flow cytometry to provide a convenient and real-time quantification of bacterial invasiveness in a heterogeneous population of cells. We invaded MCF-7, A549, and HEK-293 cells with the E. coli vector and measured RFP using imaging flow cytometry. We found high cellular infection of up to 70.47% in MCF-7 compared to 27.4% and 26.2% in A549 and HEK-293 cells, respectively. The quantitative evaluation of internalized E. coli is rapid and cell-dependent, and it distinctively differentiates between attached and cytosolic bacteria while showing the degree of cellular invasiveness. This imaging flow cytometry approach can be applied broadly to study host-bacteria interaction.
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Affiliation(s)
- Rasaq Olajide Akinsola
- School of Science, Monash University Malaysia, Bandar Sunway 47500, Selangor Darul Ehsan, Malaysia
| | - Malik Adewoyin
- Faculty of Dentistry, Universiti Kebangsaan Malaysia Jalan Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia
| | - Choon-Weng Lee
- Institute of Biological Sciences, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Edmund Ui-Hang Sim
- Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300, Sarawak, Malaysia
| | - Kumaran Narayanan
- School of Science, Monash University Malaysia, Bandar Sunway 47500, Selangor Darul Ehsan, Malaysia.
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Proteogenomic discovery of sORF-encoded peptides associated with bacterial virulence in Yersinia pestis. Commun Biol 2021; 4:1248. [PMID: 34728737 PMCID: PMC8563848 DOI: 10.1038/s42003-021-02759-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 10/08/2021] [Indexed: 11/08/2022] Open
Abstract
Plague caused by Yersinia pestis is one of the deadliest diseases. However, many molecular mechanisms of bacterial virulence remain unclear. This study engaged in the discovery of small open reading frame (sORF)-encoded peptides (SEPs) in Y. pestis. An integrated proteogenomic pipeline was established, and an atlas containing 76 SEPs was described. Bioinformatic analysis indicated that 20% of these SEPs were secreted or localized to the transmembrane and that 33% contained functional domains. Two SEPs, named SEPs-yp1 and -yp2 and encoded in noncoding regions, were selected by comparative peptidomics analysis under host-specific environments and high-salinity stress. They displayed important roles in the regulation of antiphagocytic capability in a thorough functional assay. Remarkable attenuation of virulence in mice was observed in the SEP-deleted mutants. Further global proteomic analysis indicated that SEPs-yp1 and -yp2 affected the bacterial metabolic pathways, and SEP-yp1 was associated with the bacterial virulence by modulating the expression of key virulence factors of the Yersinia type III secretion system. Our study provides a rich resource for research on Y. pestis and plague, and the findings on SEP-yp1 and SEP-yp2 shed light on the molecular mechanism of bacterial virulence. Shiyang Cao, Xinyue Liu, Yin Huang, and Yanfeng Yan et al. utilized an integrated proteogenomic approach to describe an atlas of small open reading frame-encoded peptides (SEPs) in the pathogen, Yersinia pestis. They demonstrate that two of these SEPs are associated with regulation of bacterial virulence, and altogether develop a valuable resource for future research into Y. pestis physiology.
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Structure of the Yersinia injectisome in intracellular host cell phagosomes revealed by cryo FIB electron tomography. J Struct Biol 2021; 213:107701. [PMID: 33549695 DOI: 10.1016/j.jsb.2021.107701] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/17/2020] [Accepted: 01/14/2021] [Indexed: 02/03/2023]
Abstract
Many pathogenic bacteria use the type III secretion system (T3SS), or injectisome, to secrete toxins into host cells. These protruding systems are primary targets for drug and vaccine development. Upon contact between injectisomes and host membranes, toxin secretion is triggered. How this works structurally and functionally is yet unknown. Using cryo-focused ion beam milling and cryo-electron tomography, we visualized injectisomes of Yersinia enterocolitica inside the phagosomes of infected human myeloid cells in a close-to-native state. We observed that a minimum needle length is required for injectisomes to contact the host membrane and bending of host membranes by some injectisomes that contact the host. Through subtomogram averaging, the structure of the entire injectisome was determined, which revealed structural differences in the cytosolic sorting platform compared to other bacteria. These findings contribute to understanding how injectisomes secrete toxins into host cells and provides the indispensable native context. The application of these cryo-electron microscopy techniques paves the way for the study of the 3D structure of infection-relevant protein complexes in host-pathogen interactions.
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17
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The Yersinia pestis GTPase BipA Promotes Pathogenesis of Primary Pneumonic Plague. Infect Immun 2021; 89:IAI.00673-20. [PMID: 33257531 PMCID: PMC7822129 DOI: 10.1128/iai.00673-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 11/11/2020] [Indexed: 12/27/2022] Open
Abstract
Yersinia pestis is a highly virulent pathogen and the causative agent of bubonic, septicemic, and pneumonic plague. Primary pneumonic plague caused by inhalation of respiratory droplets contaminated with Y. pestis is nearly 100% lethal within 4 to 7 days without antibiotic intervention. Pneumonic plague progresses in two phases, beginning with extensive bacterial replication in the lung with minimal host responsiveness, followed by the abrupt onset of a lethal proinflammatory response. The precise mechanisms by which Y. pestis is able to colonize the lung and survive two very distinct disease phases remain largely unknown. To date, a few bacterial virulence factors, including the Ysc type 3 secretion system, are known to contribute to the pathogenesis of primary pneumonic plague. The bacterial GTPase BipA has been shown to regulate expression of virulence factors in a number of Gram-negative bacteria, including Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica serovar Typhi. However, the role of BipA in Y. pestis has yet to be investigated. Here, we show that BipA is a Y. pestis virulence factor that promotes defense against early neutrophil-mediated bacterial killing in the lung. This work identifies a novel Y. pestis virulence factor and highlights the importance of early bacterial/neutrophil interactions in the lung during primary pneumonic plague.
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18
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Visualization of Bacteria-Mediated Gene Delivery Using High-Resolution Electron and Confocal Microscopy. Methods Mol Biol 2020. [PMID: 33336268 DOI: 10.1007/978-1-0716-0943-9_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Visual analysis of the gene delivery process when using invasive bacteria as a vector has been conventionally performed using standard light and fluorescence microscopy. These microscopes can provide basic information on the invasiveness of the bacterial vector including the ability of the vector to successfully adhere to the cell membrane. Standard microscopy techniques however fall short when finer details including membrane attachment as well as internalization into the cytoplasm are desired. High-resolution visual analysis of bacteria-mediated gene delivery can allow accurate measurement of the adherence and internalization capabilities of engineered vectors. Here, we describe the use of scanning electron microscopy (SEM) to directly quantify vectors when they are external to the cell wall, and confocal microscopy to evaluate the vectors when they have internalized into the cytoplasm. By performing the invasion procedure on microscope coverslips, cells can be easily prepared for analysis using electron or confocal microscopes. Imaging the invasion complexes in high resolution can provide important insights into the behavior of bacterial vectors including E. coli, Listeria, and Salmonella when invading their target cells to deliver DNA and other molecules.
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19
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Kumar P, Kandi SK, Mukhopadhyay K, Rawat DS. Synthesis of novel monocarbonyl curcuminoids, evaluation of their efficacy against MRSA, including ex vivo infection model and their mechanistic studies. Eur J Med Chem 2020; 195:112276. [PMID: 32279050 DOI: 10.1016/j.ejmech.2020.112276] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/27/2020] [Accepted: 03/24/2020] [Indexed: 02/06/2023]
Abstract
In continuation of our effort to improve the physiological stability and the antibacterial activity of curcuminoids against drug-resistant bacteria, a series of novel monocarbonyl curcuminoids were synthesized and screened for antibacterial activity against S. aureus and E. coli strains. These curcuminoids showed potent antibacterial activity against both methicillin-sensitive and methicillin-resistant strains of S. aureus with MIC values 2-8 and 4-16 μg/mL, respectively. They also exhibited moderate potency against E. coli strains. The four most active curcuminoids (7d, 7i, 7m, and 7p) were on further investigation found to be very stable under physiological conditions, non-hemolytic, and non-toxic toward mammalian cells up to 150 μg/mL concentration. Mechanistic studies revealed that these curcuminoids displayed potent bactericidal activity by targeting cell membranes. Further, in an ex vivo mammalian co-culture infection model study, remarkably, the curcuminoids 7i and 7p were able to clear the internalized bacteria in mammalian cells and the activity was found to be superior to conventional antibiotics such as vancomycin and linezolid. Therefore, the present study affords us water-soluble, stable, non-toxic curcuminoids that may serve as lead molecules for development as antibacterial agents against MRSA infections.
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Affiliation(s)
- Prince Kumar
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | | | - Kasturi Mukhopadhyay
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Diwan S Rawat
- Department of Chemistry, University of Delhi, Delhi, 110007, India.
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20
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Gestal MC, Howard LK, Dewan K, Johnson HM, Barbier M, Bryant C, Soumana IH, Rivera I, Linz B, Blas-Machado U, Harvill ET. Enhancement of immune response against Bordetella spp. by disrupting immunomodulation. Sci Rep 2019; 9:20261. [PMID: 31889098 PMCID: PMC6937331 DOI: 10.1038/s41598-019-56652-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/12/2019] [Indexed: 12/27/2022] Open
Abstract
Well-adapted pathogens must evade clearance by the host immune system and the study of how they do this has revealed myriad complex strategies and mechanisms. Classical bordetellae are very closely related subspecies that are known to modulate adaptive immunity in a variety of ways, permitting them to either persist for life or repeatedly infect the same host. Exploring the hypothesis that exposure to immune cells would cause bordetellae to induce expression of important immunomodulatory mechanisms, we identified a putative regulator of an immunomodulatory pathway. The deletion of btrS in B. bronchiseptica did not affect colonization or initial growth in the respiratory tract of mice, its natural host, but did increase activation of the inflammasome pathway, and recruitment of inflammatory cells. The mutant lacking btrS recruited many more B and T cells into the lungs, where they rapidly formed highly organized and distinctive Bronchial Associated Lymphoid Tissue (BALT) not induced by any wild type Bordetella species, and a much more rapid and strong antibody response than observed with any of these species. Immunity induced by the mutant was measurably more robust in all respiratory organs, providing completely sterilizing immunity that protected against challenge infections for many months. Moreover, the mutant induced sterilizing immunity against infection with other classical bordetellae, including B. pertussis and B. parapertussis, something the current vaccines do not provide. These findings reveal profound immunomodulation by bordetellae and demonstrate that by disrupting it much more robust protective immunity can be generated, providing a pathway to greatly improve vaccines and preventive treatments against these important pathogens.
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Affiliation(s)
- Monica C Gestal
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
| | - Laura K Howard
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Kalyan Dewan
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Hannah M Johnson
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Mariette Barbier
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University, Morgantown, WV, United States of America
- Vaccine Development Center at West Virginia University Health Sciences Center, Morgantown, West Virginia, United States of America
| | - Clare Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
| | - Illiassou Hamidou Soumana
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Israel Rivera
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Bodo Linz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Uriel Blas-Machado
- Department of Pathology, Athens Veterinary Diagnostic Laboratory, University of Georgia, Athens, Georgia, United States of America
| | - Eric T Harvill
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America.
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21
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Evaluation of in vitro and in vivo antibiotic efficacy against a novel bioluminescent Shigella flexneri. Sci Rep 2019; 9:13567. [PMID: 31537849 PMCID: PMC6753072 DOI: 10.1038/s41598-019-49729-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 08/30/2019] [Indexed: 12/13/2022] Open
Abstract
Shigella spp., the bacteria responsible for shigellosis, are one of the leading causes of diarrheal morbidity and mortality amongst children. There is a pressing need for the development of novel therapeutics, as resistance of Shigella to many currently used antibiotics is rapidly emerging. This paper describes the development of robust in vitro and in vivo tools to study antibiotic efficacy against Shigella flexneri. A novel bioluminescent S. flexneri strain (S. flexneri lux1) was generated, which can be used in a mammalian epithelial cell co-culture assay to evaluate antibiotic intracellular and extracellular efficacy. In addition, the S. flexneri lux1 strain was used with an intraperitoneal (IP) murine model of shigellosis to test the efficacy of ciprofloxacin and ampicillin. Both antibiotics significantly reduced the observed radiance from the gastrointestinal tissue of infected mice compared to vehicle control. Furthermore, plated gastrointestinal tissue homogenate confirmed antibiotic treatment significantly reduced the S. flexneri infection. However, in contrast to the results generated with tissue homogenate, the radiance data was not able to distinguish between the efficacy of ampicillin and ciprofloxacin. Compared to traditional methods, these models can be utilized for efficient screening of novel antibiotics aiding in the discovery of new treatments against shigellosis.
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22
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Nguyen T, Kim T, Ta HM, Yeo WS, Choi J, Mizar P, Lee SS, Bae T, Chaurasia AK, Kim KK. Targeting Mannitol Metabolism as an Alternative Antimicrobial Strategy Based on the Structure-Function Study of Mannitol-1-Phosphate Dehydrogenase in Staphylococcus aureus. mBio 2019; 10:e02660-18. [PMID: 31289190 PMCID: PMC6623548 DOI: 10.1128/mbio.02660-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/05/2019] [Indexed: 11/22/2022] Open
Abstract
Mannitol-1-phosphate dehydrogenase (M1PDH) is a key enzyme in Staphylococcus aureus mannitol metabolism, but its roles in pathophysiological settings have not been established. We performed comprehensive structure-function analysis of M1PDH from S. aureus USA300, a strain of community-associated methicillin-resistant S. aureus, to evaluate its roles in cell viability and virulence under pathophysiological conditions. On the basis of our results, we propose M1PDH as a potential antibacterial target. In vitro cell viability assessment of ΔmtlD knockout and complemented strains confirmed that M1PDH is essential to endure pH, high-salt, and oxidative stress and thus that M1PDH is required for preventing osmotic burst by regulating pressure potential imposed by mannitol. The mouse infection model also verified that M1PDH is essential for bacterial survival during infection. To further support the use of M1PDH as an antibacterial target, we identified dihydrocelastrol (DHCL) as a competitive inhibitor of S. aureus M1PDH (SaM1PDH) and confirmed that DHCL effectively reduces bacterial cell viability during host infection. To explain physiological functions of SaM1PDH at the atomic level, the crystal structure of SaM1PDH was determined at 1.7-Å resolution. Structure-based mutation analyses and DHCL molecular docking to the SaM1PDH active site followed by functional assay identified key residues in the active site and provided the action mechanism of DHCL. Collectively, we propose SaM1PDH as a target for antibiotic development based on its physiological roles with the goals of expanding the repertory of antibiotic targets to fight antimicrobial resistance and providing essential knowledge for developing potent inhibitors of SaM1PDH based on structure-function studies.IMPORTANCE Due to the shortage of effective antibiotics against drug-resistant Staphylococcus aureus, new targets are urgently required to develop next-generation antibiotics. We investigated mannitol-1-phosphate dehydrogenase of S. aureus USA300 (SaM1PDH), a key enzyme regulating intracellular mannitol levels, and explored the possibility of using SaM1PDH as a target for developing antibiotic. Since mannitol is necessary for maintaining the cellular redox and osmotic potential, the homeostatic imbalance caused by treatment with a SaM1PDH inhibitor or knockout of the gene encoding SaM1PDH results in bacterial cell death through oxidative and/or mannitol-dependent cytolysis. We elucidated the molecular mechanism of SaM1PDH and the structural basis of substrate and inhibitor recognition by enzymatic and structural analyses of SaM1PDH. Our results strongly support the concept that targeting of SaM1PDH represents an alternative strategy for developing a new class of antibiotics that cause bacterial cell death not by blocking key cellular machinery but by inducing cytolysis and reducing stress tolerance through inhibition of the mannitol pathway.
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Affiliation(s)
- Thanh Nguyen
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Truc Kim
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Hai Minh Ta
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Won Sik Yeo
- Department of Microbiology and Immunology, Indiana University School of Medicine Northwest, Gary, Indiana, USA
| | - Jongkeun Choi
- Department of Chemical Engineering, Chungwoon University, Incheon, South Korea
| | - Pushpak Mizar
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Seung Seo Lee
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine Northwest, Gary, Indiana, USA
| | - Akhilesh Kumar Chaurasia
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
- Samsung Biomedical Research Institute, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
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Alternative Enzyme Protection Assay To Overcome the Drawbacks of the Gentamicin Protection Assay for Measuring Entry and Intracellular Survival of Staphylococci. Infect Immun 2019; 87:IAI.00119-19. [PMID: 30782857 DOI: 10.1128/iai.00119-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 12/28/2022] Open
Abstract
Precise enumeration of living intracellular bacteria is the key step to estimate the invasion potential of pathogens and host immune responses to understand the mechanism and kinetics of bacterial pathogenesis. Therefore, quantitative assessment of host-pathogen interactions is essential for development of novel antibacterial therapeutics for infectious disease. The gentamicin protection assay (GPA) is the most widely used method for these estimations by counting the CFU of intracellular living pathogens. Here, we assess the longstanding drawbacks of the GPA by employing an antistaphylococcal endopeptidase as a bactericidal agent to kill extracellular Staphylococcus aureus We found that the difference between the two methods for the recovery of intracellular CFU of S. aureus was about 5 times. We prove that the accurate number of intracellular CFU could not be precisely determined by the GPA due to the internalization of gentamicin into host cells during extracellular bacterial killing. We further demonstrate that lysostaphin-mediated extracellular bacterial clearance has advantages for measuring the kinetics of bacterial internalization on a minute time scale due to the fast and tunable activity and the inability of protein to permeate the host cell membrane. From these results, we propose that accurate quantification of intracellular bacteria and measurement of internalization kinetics can be achieved by employing enzyme-mediated killing of extracellular bacteria (enzyme protection assay [EPA]) rather than the host-permeative drug gentamicin, which is known to alter host physiology.
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24
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Artificial Selection for Pathogenicity Mutations in Staphylococcus aureus Identifies Novel Factors Relevant to Chronic Infection. Infect Immun 2019; 87:IAI.00884-18. [PMID: 30642903 DOI: 10.1128/iai.00884-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/10/2019] [Indexed: 02/06/2023] Open
Abstract
Adaptation of Staphylococcus aureus to host microenvironments during chronic infection involves spontaneous mutations, yet changes underlying adaptive phenotypes remain incompletely explored. Here, we employed artificial selection and whole-genome sequencing to better characterize spontaneous chromosomal mutations that alter two pathogenicity phenotypes relevant to chronic infection in S. aureus: intracellular invasiveness and intracellular cytotoxicity. We identified 23 genes whose alteration coincided with enhanced virulence, 11 that were previously known and 12 (52%) that had no previously described role in S. aureus pathogenicity. Using precision genome editing, transposon mutants, and gene complementation, we empirically assessed the contributions of individual genes to the two virulence phenotypes. We functionally validated 14 of 21 genes tested as measurably influencing invasion and/or cytotoxicity, including 8 newly implicated by this study. We identified inactivating mutations (murA, ndhC, and a hypothetical membrane protein) and gain-of-function mutations (aroE Thr182Ile, yhcF Thr74Ile, and Asp486Glu in a hypothetical peptidase) in previously unrecognized S. aureus virulence genes that enhance pathogenesis when introduced into a clean genetic background, as well as a novel activating mutation in the known virulence regulator gene saeS (Ala106Thr). Investigation of potentially epistatic interactions identified a tufA mutation (Ala271Val) that enhances virulence only in the context of purine operon repressor gene (purR) inactivation. This project reveals a functionally diverse range of genes affected by gain- or loss-of-function mutations that contribute to S. aureus adaptive virulence phenotypes. More generally, the work establishes artificial selection as a means to determine the genetic mechanisms underlying complex bacterial phenotypes relevant to adaptation during infection.
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Lane K, Andres-Terre M, Kudo T, Monack DM, Covert MW. Escalating Threat Levels of Bacterial Infection Can Be Discriminated by Distinct MAPK and NF-κB Signaling Dynamics in Single Host Cells. Cell Syst 2019; 8:183-196.e4. [DOI: 10.1016/j.cels.2019.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/08/2018] [Accepted: 02/26/2019] [Indexed: 12/18/2022]
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Flannagan RS, Heinrichs DE. A Fluorescence Based-Proliferation Assay for the Identification of Replicating Bacteria Within Host Cells. Front Microbiol 2018; 9:3084. [PMID: 30619165 PMCID: PMC6299164 DOI: 10.3389/fmicb.2018.03084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/29/2018] [Indexed: 01/01/2023] Open
Abstract
Understanding host pathogen interactions is paramount to the development of novel antimicrobials. An important facet of this pursuit is the accurate characterization of pathogen replication within infected host cells. Here we describe the use of a fluorescence-based proliferation assay to identify intracellular populations of replicating bacteria at the subcellular level. Using Staphylococcus aureus as a model Gram-positive bacterial pathogen and macrophages as a model host phagocyte, we demonstrate this assay can be used to reliably identify individual phagocytes that contain replicating bacteria. Furthermore, we demonstrate this assay is compatible with additional cellular probes that enable characterization of cellular compartments in which replicating bacteria reside. Finally, we demonstrate that this assay facilitates the investigation of both Gram-negative and Gram-positive bacteria within host cells.
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Affiliation(s)
- Ronald S Flannagan
- Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada
| | - David E Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada
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Staphylococcus aureus Uses the GraXRS Regulatory System To Sense and Adapt to the Acidified Phagolysosome in Macrophages. mBio 2018; 9:mBio.01143-18. [PMID: 30018109 PMCID: PMC6050959 DOI: 10.1128/mbio.01143-18] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Macrophages are critical to innate immunity due to their ability to phagocytose bacteria. The macrophage phagolysosome is a highly acidic organelle with potent antimicrobial properties, yet remarkably, ingested Staphylococcus aureus replicates within this niche. Herein we demonstrate that S. aureus requires the GraXRS regulatory system for growth within this niche, while the SaeRS and AgrAC two-component regulatory systems and the α-phenol soluble modulins are dispensable. Importantly, we find that it is exposure to acidic pH that is required for optimal growth of S. aureus inside fully acidified macrophage phagolysosomes. Exposure of S. aureus to acidic pH evokes GraS signaling, which in turn elicits an adaptive response that endows the bacteria with increased resistance to antimicrobial effectors, such as antimicrobial peptides, encountered inside macrophage phagolysosomes. Notably, pH-dependent induction of antimicrobial peptide resistance in S. aureus requires the GraS sensor kinase. GraS and MprF, a member of the GraS regulon, play an important role for bacterial survival in the acute stages of systemic infection, where in murine models of infection, S. aureus resides within liver-resident Kupffer cells. We conclude that GraXRS represents a vital regulatory system that functions to allow S. aureus to evade killing, prior to commencement of replication, within host antibacterial immune cells. S. aureus can infect any site of the body, including the microbicidal phagolysosome of the macrophage. The ability of S. aureus to infect diverse niches necessitates that the bacteria be highly adaptable. Here we show that S. aureus responds to phagolysosome acidification to evoke changes in gene expression that enable the bacteria to resist phagolysosomal killing and to promote replication. Toxin production is dispensable for this response; however, the bacteria require the sensor kinase GraS, which transduces signals in response to acidic pH. GraS is necessary for phagolysosomal replication and survival of S. aureus in the acute stage of systemic infection. Disruption of this S. aureus adaptation would render S. aureus susceptible to phagocyte restriction.
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