Modulation of Pathogenicity and Virulence by Molecules and Nanostructures

A special issue of Pathogens (ISSN 2076-0817).

Deadline for manuscript submissions: closed (31 July 2016) | Viewed by 25826

Special Issue Editors


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Guest Editor
Department of Science and Engineereing of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, Politehnica University of Bucharest, RO-011061 Bucharest, Romania
Interests: synthesis and characterization of nanobiomaterials; polymers; pharmaceutical nanotechnology; drug delivery; anti-biofilm surfaces; nanomodified surfaces; natural products
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
1. Department of Microbiology and Immunology, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania
2. The Research Institute of the University of Bucharest, ICUB, 060023 Bucharest, Romania
Interests: microbiology; immunology; new antimicrobial agents; host-pathogen signaling; infection control; antimicrobial nanomaterials; bacterial pathogenesis; virulence factors; quorum sensing; biofilms; antibacterial activity; antibiotic resistance; Staphylococcus aureus; Escherichia coli; Pseudomonas aeruginosa; microbial molecular biology; bioactive materials; nanotechnology; nanoengineering
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Because of the huge medical, social, industrial and economic impact, antimicrobial resistance phenomenon is currently considered an aspect of worldwide interest. Alternative therapeutic approaches are intensively studied for the design of efficient antimicrobials in order to reduce morbidity and mortality associated with the emergence of resistant pathogens. Currently, strategies aiming to modulate pathogenicity and virulence of microorganisms are of a particular interest, since it is considered that they could reduce the rate of antibiotic resistance and limit the spread of difficult to treat infections. However, the scientific progress on this field is still limited mainly due to the difficulty to find and design efficient molecules and structures that could interact efficiently with the highly complicated molecular signalling pathways that control virulence. Many molecular signalling systems are yet unknown and their study progresses slowly due to their complexity and molecular and sub-molecular scale processes that are difficult to control. In this context, the science of nanometer size materials could provide the appropriate tools both to investigate alternative methods to modulate pathogenicity and virulence, but also to improve the investigation methods for the complex microbial signalling in order to facilitate the identification of new therapeutic targets. Moreover, nanostructures are currently utilized for multiple biomedical approaches that aim to develop novel antimicrobial therapies, significant progress being made on the field of drug delivery and targeted release of antimicrobials. Nanotechnology could also be useful for the stabilization and efficiency improvement of recently identified molecules able to interfere with microbial virulence and behaviour.

This Special Issue aims to bring together the most recent and interesting advances on the field of molecular microbiology and the impact of natural (i.e., microbial and host-related) molecules in the control of pathogenicity and virulence, and to highlight the impact of nanostructures in the development of novel and efficient antimicrobial approaches by exploitation of different molecular and nanosized structures.

Dr. Alexandru Mihai Grumezescu
Dr. Alina Maria Holban
Guest Editors

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Keywords

  • Molecular therapy
  • Microbial signaling
  • Host-pathogens interactions
  • Virulence modulation
  • Anti-biofilm strategies
  • Natural antimicrobials
  • Functionalized nanomaterials
  • Antimicrobial drug delivery systems
  • Nanosystems for infection control
  • Nanosized materials in molecular signaling

Published Papers (3 papers)

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Research

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1977 KiB  
Article
Antibiotic Resistance and Virulence Phenotypes of Recent Bacterial Strains Isolated from Urinary Tract Infections in Elderly Patients with Prostatic Disease
by Cristina Delcaru, Paulina Podgoreanu, Ionela Alexandru, Nela Popescu, Luminiţa Măruţescu, Coralia Bleotu, George Dan Mogoşanu, Mariana Carmen Chifiriuc, Marinela Gluck and Veronica Lazăr
Pathogens 2017, 6(2), 22; https://doi.org/10.3390/pathogens6020022 - 31 May 2017
Cited by 21 | Viewed by 5634
Abstract
Acute bacterial prostatitis is one of the frequent complications of urinary tract infection (UTI). From the approximately 10% of men having prostatitis, 7% experience a bacterial prostatitis. The purpose of this study was to investigate the prevalence of uropathogens associated with UTIs in [...] Read more.
Acute bacterial prostatitis is one of the frequent complications of urinary tract infection (UTI). From the approximately 10% of men having prostatitis, 7% experience a bacterial prostatitis. The purpose of this study was to investigate the prevalence of uropathogens associated with UTIs in older patients with benign prostatic hyperplasia and to assess their susceptibility to commonly prescribed antibiotics as well as the relationships between microbial virulence and resistance features. Uropathogenic Escherichia coli was found to be the most frequent bacterial strain isolated from patients with benign prostatic hyperplasia, followed by Enterococcus spp., Enterobacter spp., Klebsiella spp., Proteus spp., Pseudomonas aeruginosa, and Serratia marcescens. Increased resistance rates to tetracyclines, quinolones, and sulfonamides were registered. Besides their resistance profiles, the uropathogenic isolates produced various virulence factors with possible implications in the pathogenesis process. The great majority of the uropathogenic isolates revealed a high capacity to adhere to HEp-2 cell monolayer in vitro, mostly exhibiting a localized adherence pattern. Differences in the repertoire of soluble virulence factors that can affect bacterial growth and persistence within the urinary tract were detected. The Gram-negative strains produced pore-forming toxins—such as hemolysins, lecithinases, and lipases—proteases, siderophore-like molecules resulted from the esculin hydrolysis and amylases, while Enterococcus sp. strains were positive only for caseinase and esculin hydrolase. Our study demonstrates that necessity of investigating the etiology and local resistance patterns of uropathogenic organisms, which is crucial for determining appropriate empirical antibiotic treatment in elderly patients with UTI, while establishing correlations between resistance and virulence profiles could provide valuable input about the clinical evolution and recurrence rates of UTI. Full article
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RT-qPCR Analysis of 15 Genes Encoding Putative Surface Proteins Involved in Adherence of Listeria monocytogenes
by Hung King Tiong and Peter M. Muriana
Pathogens 2016, 5(4), 60; https://doi.org/10.3390/pathogens5040060 - 01 Oct 2016
Cited by 6 | Viewed by 6098
Abstract
L. monocytogenes adherence to food-associated abiotic surfaces and the development of biofilms as one of the underlying reasons for the contamination of ready-to-eat products is well known. The over-expression of internalins that improves adherence has been noted in cells growing as attached cells [...] Read more.
L. monocytogenes adherence to food-associated abiotic surfaces and the development of biofilms as one of the underlying reasons for the contamination of ready-to-eat products is well known. The over-expression of internalins that improves adherence has been noted in cells growing as attached cells or at elevated incubation temperatures. However, the role of other internalin-independent surface proteins as adhesins has been uncharacterized to date. Using two strains each of weakly- and strongly-adherent L. monocytogenes as platforms for temperature-dependent adherence assays and targeted mRNA analyses, these observations (i.e., sessile- and/or temperature-dependent gene expression) were further investigated. Microplate fluorescence assays of both surface-adherent strains exhibited significant (P < 0.05) adherence at higher incubation temperature (42 °C). Of the 15 genes selected for RT-qPCR, at least ten gene transcripts recovered from cells (weakly-adherent strain CW35, strongly-adherent strain 99-38) subject to various growth conditions were over expressed [planktonic/30 °C (10), sessile/30 °C (12), planktonic/42 °C (10)] compared to their internal control (16SrRNA transcripts). Of four genes overexpressed in all three conditions tested, three and one were implicated as virulence factors and unknown function, respectively. PCR analysis of six unexpressed genes revealed that CW35 possessed an altered genome. The results suggest the presence of other internalin-independent adhesins (induced by growth temperature and/or substratum) and that a group of suspect protein members are worthy of further analysis for their potential role as surface adhesins. Analysis of the molecular basis of adherence properties of isolates of L. monocytogenes from food-associated facilities may help identify sanitation regimens to prevent cell attachment and biofilm formation on abiotic surfaces that could play a role in reducing foodborne illness resulting from Listeria biofilms. Full article
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Review

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Review
Microbial Biofilms in Urinary Tract Infections and Prostatitis: Etiology, Pathogenicity, and Combating strategies
by Cristina Delcaru, Ionela Alexandru, Paulina Podgoreanu, Mirela Grosu, Elisabeth Stavropoulos, Mariana Carmen Chifiriuc and Veronica Lazar
Pathogens 2016, 5(4), 65; https://doi.org/10.3390/pathogens5040065 - 30 Nov 2016
Cited by 124 | Viewed by 13199
Abstract
Urinary tract infections (UTIs) are one of the most important causes of morbidity and health care spending affecting persons of all ages. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. UTIs associated with microbial [...] Read more.
Urinary tract infections (UTIs) are one of the most important causes of morbidity and health care spending affecting persons of all ages. Bacterial biofilms play an important role in UTIs, responsible for persistent infections leading to recurrences and relapses. UTIs associated with microbial biofilms developed on catheters account for a high percentage of all nosocomial infections and are the most common source of Gram-negative bacteremia in hospitalized patients. The purpose of this mini-review is to present the role of microbial biofilms in the etiology of female UTI and different male prostatitis syndromes, their consequences, as well as the challenges for therapy Full article
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