scholarly journals Clinical S. aureus Isolates Vary in Their Virulence to Promote Adaptation to the Host

Toxins ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 135 ◽  
Author(s):  
Lorena Tuchscherr ◽  
Christine Pöllath ◽  
Anke Siegmund ◽  
Stefanie Deinhardt-Emmer ◽  
Verena Hoerr ◽  
...  
Keyword(s):  
Treatment Strategies ◽  
Bacterial Virulence ◽  
Chronic Infections ◽  
Host Pathogen Interaction ◽  
Genotypic Analysis ◽  
Wide Range ◽  
Severe Infections ◽  
Small Colony ◽  
Low Cytotoxicity ◽  
Infection Types

Staphylococcus aureus colonizes epithelial surfaces, but it can also cause severe infections. The aim of this work was to investigate whether bacterial virulence correlates with defined types of tissue infections. For this, we collected 10–12 clinical S. aureus strains each from nasal colonization, and from patients with endoprosthesis infection, hematogenous osteomyelitis, and sepsis. All strains were characterized by genotypic analysis, and by the expression of virulence factors. The host–pathogen interaction was studied through several functional assays in osteoblast cultures. Additionally, selected strains were tested in a murine sepsis/osteomyelitis model. We did not find characteristic bacterial features for the defined infection types; rather, a wide range in all strain collections regarding cytotoxicity and invasiveness was observed. Interestingly, all strains were able to persist and to form small colony variants (SCVs). However, the low-cytotoxicity strains survived in higher numbers, and were less efficiently cleared by the host than the highly cytotoxic strains. In summary, our results indicate that not only destructive, but also low-cytotoxicity strains are able to induce infections. The low-cytotoxicity strains can successfully survive, and are less efficiently cleared from the host than the highly cytotoxic strains, which represent a source for chronic infections. The understanding of this interplay/evolution between the host and the pathogen during infection, with specific attention towards low-cytotoxicity isolates, will help to optimize treatment strategies for invasive and therapy-refractory infection courses.

scholarly journals Dampening Host Sensing and Avoiding Recognition inPseudomonas aeruginosaPneumonia

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Cristina Cigana ◽  
Nicola Ivan Lorè ◽  
Maria Lina Bernardini ◽  
Alessandra Bragonzi
Keyword(s):  
Chronic Infection ◽  
Acute Infection ◽  
Immune Surveillance ◽  
Opportunistic Pathogen ◽  
Bacterial Virulence ◽  
Chronic Infections ◽  
Pathogenic Variants ◽  
Wide Range ◽  
Life Threatening ◽  
Normal Immune Response

Pseudomonas aeruginosais an opportunistic pathogen and causes a wide range of acute and chronic infections.P. aeruginosainfections are kept in check by an effective immune surveillance in the healthy host, while any imbalance or defect in the normal immune response can manifest in disease. Invasive acute infection in the immunocompromised patients is mediated by potent extracellular and cell bound bacterial virulence factors. Life-threatening chronic infection in cystic fibrosis patients is maintained by pathogenic variants that contribute to evade detection and clearance by the immune system. Here, we reviewed the molecular basis of receptor-mediated recognition ofP. aeruginosaand their role in initiating inflammation and the colonization. In addition, the consequence of theP. aeruginosagenetic adaptation for the antibacterial defence and the maintaining of chronic infection are discussed.

scholarly journals Advances and Applications of Water Phytoremediation: A Potential Biotechnological Approach for the Treatment of Heavy Metals from Contaminated Water

2021 ◽  
Vol 18 (10) ◽  
pp. 5215
Author(s):  
Cristián Raziel Delgado-González ◽  
Alfredo Madariaga-Navarrete ◽  
José Miguel Fernández-Cortés ◽  
Margarita Islas-Pelcastre ◽  
Goldie Oza ◽  
...  
Keyword(s):  
Water Quality ◽  
Plant Species ◽  
Treatment Strategies ◽  
Pollution Sources ◽  
Water Contaminants ◽  
Biotechnological Approach ◽  
Wide Range ◽  
Great Relevance ◽  
Multidisciplinary Perspective ◽  
Viable Method

Potable and good-quality drinking water availability is a serious global concern, since several pollution sources significantly contribute to low water quality. Amongst these pollution sources, several are releasing an array of hazardous agents into various environmental and water matrices. Unfortunately, there are not very many ecologically friendly systems available to treat the contaminated environment exclusively. Consequently, heavy metal water contamination leads to many diseases in humans, such as cardiopulmonary diseases and cytotoxicity, among others. To solve this problem, there are a plethora of emerging technologies that play an important role in defining treatment strategies. Phytoremediation, the usage of plants to remove contaminants, is a technology that has been widely used to remediate pollution in soils, with particular reference to toxic elements. Thus, hydroponic systems coupled with bioremediation for the removal of water contaminants have shown great relevance. In this review, we addressed several studies that support the development of phytoremediation systems in water. We cover the importance of applied science and environmental engineering to generate sustainable strategies to improve water quality. In this context, the phytoremediation capabilities of different plant species and possible obstacles that phytoremediation systems may encounter are discussed with suitable examples by comparing different mechanistic processes. According to the presented data, there are a wide range of plant species with water phytoremediation potential that need to be studied from a multidisciplinary perspective to make water phytoremediation a viable method.

scholarly journals An In Vitro Cell Culture Model for Pyoverdine-Mediated Virulence

Pathogens ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Donghoon Kang ◽  
Natalia V. Kirienko
Keyword(s):  
Cell Culture ◽  
Virulence Factors ◽  
Model Organisms ◽  
Cell Culture Model ◽  
Chronic Infections ◽  
In Vitro Cell Culture ◽  
Mitochondrial Homeostasis ◽  
Culture Model ◽  
Wide Range

Pseudomonas aeruginosa is a multidrug-resistant, opportunistic pathogen that utilizes a wide-range of virulence factors to cause acute, life-threatening infections in immunocompromised patients, especially those in intensive care units. It also causes debilitating chronic infections that shorten lives and worsen the quality of life for cystic fibrosis patients. One of the key virulence factors in P. aeruginosa is the siderophore pyoverdine, which provides the pathogen with iron during infection, regulates the production of secreted toxins, and disrupts host iron and mitochondrial homeostasis. These roles have been characterized in model organisms such as Caenorhabditis elegans and mice. However, an intermediary system, using cell culture to investigate the activity of this siderophore has been absent. In this report, we describe such a system, using murine macrophages treated with pyoverdine. We demonstrate that pyoverdine-rich filtrates from P. aeruginosa exhibit substantial cytotoxicity, and that the inhibition of pyoverdine production (genetic or chemical) is sufficient to mitigate virulence. Furthermore, consistent with previous observations made in C. elegans, pyoverdine translocates into cells and disrupts host mitochondrial homeostasis. Most importantly, we observe a strong correlation between pyoverdine production and virulence in P. aeruginosa clinical isolates, confirming pyoverdine’s value as a promising target for therapeutic intervention. This in vitro cell culture model will allow rapid validation of pyoverdine antivirulents in a simple but physiologically relevant manner.

Prevalence of Hand Malformations in Patients With Moebius Syndrome and Their Management

Hand ◽  
2021 ◽  
pp. 155894472199426
Author(s):  
Jose E. Telich-Tarriba ◽  
David F. Navarro-Barquin ◽  
Karol Verdezoto-Gaibor ◽  
Alexander Cardenas-Mejia
Keyword(s):  
Upper Extremity ◽  
Treatment Strategies ◽  
Abducens Nerve ◽  
Poland Syndrome ◽  
Statistical Association ◽  
Moebius Syndrome ◽  
Cross Sectional ◽  
Reconstructive Procedures ◽  
Nerve Paralysis ◽  
Wide Range

Background: Moebius syndrome is a disorder characterized by facial and abducens nerve paralysis. Patients can present a wide range of upper extremity malformations. Literature focused on orthopedic manifestations of Moebius syndrome shows variability in the prevalence and clinical presentation of upper extremity anomalies. The aim of this work is to evaluate the prevalence of upper extremity malformations in patients with Moebius syndrome, clarify its various clinical presentations, and present treatment strategies for their management. Methods: This is a retrospective, cross-sectional study including patients with Moebius syndrome and upper extremity malformations between 2012 and 2019. Data include demographic characteristics, Moebius syndrome subtype, type of malformation, affected extremity, and surgical procedures underwent. Quantitative data were recorded as mean (standard deviation [SD]), and qualitative data were expressed in terms of totals and percentages. Statistical association between Moebius syndrome subtype and development of upper extremity anomalies was evaluated using binary logistic regression. Results: Twenty-five out of 153 patients (16.3%) presented upper extremity malformations (48% male). Mean age of presentation was 9.08 ± 9.43 years. Sixty-eight percent of the malformations were unilateral. The most common presentations included Poland syndrome and simple syndactyly with 8 cases each (32%), followed by 5 cases of brachysyndactyly (20%), 3 cases of amniotic band syndrome (12%), and 1 case of cleft hand (4%). No statistical association was found between Moebius syndrome subtype and odds ratio for development of upper extremity anomalies. Thirteen patients (52%) underwent reconstructive procedures. Conclusion: Poland syndrome and syndactyly are the most common anomalies in patients with Moebius syndrome. Patients may present with a wide range of hand malformations, each patient should be carefully evaluated in order to determine whether surgical treatment is needed and to optimize rehabilitation protocols.

scholarly journals Monitoring and treatment of MDS in genetically susceptible persons

Hematology ◽  
2019 ◽  
Vol 2019 (1) ◽  
pp. 105-109 ◽  
Author(s):  
Stella M. Davies
Keyword(s):  
Bone Marrow ◽  
Dna Damage ◽  
Bone Marrow Failure ◽  
Treatment Strategies ◽  
Informed Choice ◽  
Dyskeratosis Congenita ◽  
Careful Consideration ◽  
Host Susceptibility ◽  
Bone Marrow Failure Syndromes ◽  
Severe Infections

Abstract Genetic susceptibility to myelodysplastic syndrome (MDS) occurs in children with inherited bone marrow failure syndromes, including Fanconi anemia, Shwachman Diamond syndrome, and dyskeratosis congenita. Available evidence (although not perfect) supports annual surveillance of the blood count and bone marrow in affected persons. Optimal treatment of MDS in these persons is most commonly transplantation. Careful consideration must be given to host susceptibility to DNA damage when selecting a transplant strategy, because significant dose reductions and avoidance of radiation are necessary. Transplantation before evolution to acute myeloid leukemia (AML) is optimal, because outcomes of AML are extremely poor. Children and adults can present with germline mutations in GATA2 and RUNX1, both of which are associated with a 30% to 40% chance of evolution to MDS. GATA2 deficiency may be associated with a clinically important degree of immune suppression, which can cause severe infections that can complicate transplant strategies. GATA2 and RUNX1 deficiency is not associated with host susceptibility to DNA damage, and therefore, conventional treatment strategies for MDS and AML can be used. RUNX1 deficiency has a highly variable phenotype, and MDS can occur in childhood and later in adulthood within the same families, making annual surveillance with marrow examination burdensome; however, such strategies should be discussed with affected persons, allowing an informed choice.

scholarly journals Subinhibitory Antimicrobial Concentrations: A Review of In Vitro and In Vivo Data

1992 ◽  
Vol 3 (4) ◽  
pp. 193-201 ◽  
Author(s):  
George G Zhanel ◽  
Daryl J Hoban ◽  
Godfrey KM Harding
Keyword(s):  
Antimicrobial Activity ◽  
Animal Studies ◽  
Molecular Level ◽  
Bacterial Virulence ◽  
Antibacterial Effects ◽  
Wide Range ◽  
Immune Defences

Antimicrobial activity is not an ‘all or none’ effect. An increase in the rate and extent of antimicrobial action is usually observed over a wide range of antimicrobial concentrations. Subinhibitory antimicrobial concentrations are well known to produce significant antibacterial effects, and various antimicrobials at subinhibitory concentrations have been reported to inhibit the rate of bacterial growth. Bacterial virulence may be increased or decreased by subinhibitory antimicrobial concentrations by changes in the ability of bacteria to adhere to epithelial cells or by alterations in bacterial susceptibility to host immune defences. Animal studies performed in rats, hamsters and rabbits demonstrate decreased bacterial adherence, reduced infectivity and increased survival of animals treated with subinhibitory antimicrobial concentrations compared to untreated controls. The major future role of investigation of subinhibitory antimicrobial concentrations will be to define more fully, at a molecular level, how antimicrobials exert their antibacterial effects.

scholarly journals BacA, an ABC Transporter Involved in Maintenance of Chronic Murine Infections with Mycobacterium tuberculosis

2008 ◽  
Vol 191 (2) ◽  
pp. 477-485 ◽  
Author(s):  
Pilar Domenech ◽  
Hajime Kobayashi ◽  
Kristin LeVier ◽  
Graham C. Walker ◽  
Clifton E. Barry
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Comprehensive Evaluation ◽  
Cell Envelope ◽  
Membrane Integrity ◽  
Chronic Infections ◽  
Host Pathogen Interaction ◽  
Host Pathogen ◽  
Ultimate Outcome ◽  
Inner Membrane Protein ◽  
Related Proteins

ABSTRACT BacA is an inner membrane protein associated with maintenance of chronic infections in several diverse host-pathogen interactions. To understand the function of the bacA gene in Mycobacterium tuberculosis (Rv1819c), we insertionally inactivated this gene and analyzed the resulting mutant for a variety of phenotypes. BacA deficiency in M. tuberculosis did not affect sensitivity to detergents, acidic pH, and zinc, indicating that there was no global compromise in membrane integrity, and a comprehensive evaluation of the major lipid constituents of the cell envelope failed to reveal any significant differences. Infection of mice with this mutant revealed no impact on establishment of infection but a profound effect on maintenance of extended chronic infection and ultimate outcome. As in alphaproteobacteria, deletion of BacA in M. tuberculosis led to increased bleomycin resistance, and heterologous expression of the M. tuberculosis BacA homolog in Escherichia coli conferred sensitivity to antimicrobial peptides. These results suggest a striking conservation of function for BacA-related proteins in transport of a critical molecule that determines the outcome of the host-pathogen interaction.

scholarly journals Survival ofStaphylococcus epidermidisin Fibroblasts and Osteoblasts

2018 ◽  
Vol 86 (10) ◽  
Author(s):  
Kimberly Perez ◽  
Robin Patel
Keyword(s):  
Joint Infection ◽  
Human Fibroblasts ◽  
Eukaryotic Cell ◽  
Chronic Infections ◽  
Content Type ◽  
Prosthetic Joint ◽  
Small Colony ◽  
Delayed Time ◽  
Extracellular Environment ◽  
Human And Mouse

ABSTRACTStaphylococcus epidermidisis a leading cause of infections associated with indwelling medical devices, including prosthetic joint infection. While biofilm formation is assumed to be the main mechanism underlying the chronic infectionsS. epidermidiscauses, we hypothesized thatS. epidermidisalso evades immune killing, contributing to its pathogenesis. Here, we show that prosthetic joint-associatedS. epidermidisisolates can persist intracellularly within human fibroblasts and inside human and mouse osteoblasts. We also show that the intracellularly persisting bacteria reside primarily within acidic phagolysosomes and that over the course of infection, small-colony variants are selected for. Moreover, upon eukaryotic cell death, these bacteria, which can outlive their host, can escape into the extracellular environment, providing them an opportunity to form biofilms on implant surfaces at delayed time points in implant-associated infection. In summary, the acidic phagolysosomes of fibroblasts and osteoblasts serve as reservoirs for chronic or delayedS. epidermidisinfection.

Interactions between antimicrobial drugs

1968 ◽  
Vol 6 (13) ◽  
pp. 49-51
Keyword(s):  
Drug Resistance ◽  
Bacterial Infections ◽  
Mixed Infections ◽  
Neonatal Infections ◽  
Antimicrobial Drugs ◽  
Single Drug ◽  
Wide Range ◽  
Severe Infections ◽  
Pathogenic Organisms

Treatment with a single drug is appropriate for most bacterial infections. A combination of antimicrobial drugs is indicated only in a limited number of circumstances, of which the most clearly defined is the prevention of drug resistance, as in the therapy of tuberculosis. It may be necessary to use antibiotic combinations in mixed infections, or as a temporary measure in the treatment of severe infections before bacteriological findings are available; for example, in severe neonatal infections in which a wide range of potentailly pathogenic organisms have to be considered.

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