scholarly journals The Toxin-Antitoxin MazEF Drives Staphylococcus aureus Biofilm Formation, Antibiotic Tolerance, and Chronic Infection

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Dongzhu Ma ◽  
Jonathan B. Mandell ◽  
Niles P. Donegan ◽  
Ambrose L. Cheung ◽  
Wanyan Ma ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Chronic Infection ◽  
Critical Role ◽  
Antimicrobial Treatment ◽  
Antibiotic Tolerance ◽  
Chronic Infections ◽  
Content Type ◽  
Increased Risk

ABSTRACT Staphylococcus aureus is the major organism responsible for surgical implant infections. Antimicrobial treatment of these infections often fails, leading to expensive surgical intervention and increased risk of mortality to the patient. The challenge in treating these infections is associated with the high tolerance of S. aureus biofilm to antibiotics. MazEF, a toxin-antitoxin system, is thought to be an important regulator of this phenotype, but its physiological function in S. aureus is controversial. Here, we examined the role of MazEF in developing chronic infections by comparing growth and antibiotic tolerance phenotypes in three S. aureus strains to their corresponding strains with disruption of mazF expression. Strains lacking mazF production showed increased biofilm growth and decreased biofilm antibiotic tolerance. Deletion of icaADBC in the mazF::Tn background suppressed the growth phenotype observed with mazF-disrupted strains, suggesting the phenotype was ica dependent. We confirmed these phenotypes in our murine animal model. Loss of mazF resulted in increased bacterial burden and decreased survival rate of mice compared to its wild-type strain demonstrating that loss of the mazF gene caused an increase in S. aureus virulence. Although lack of mazF gene expression increased S. aureus virulence, it was more susceptible to antibiotics in vivo. Combined, the ability of mazF to inhibit biofilm formation and promote biofilm antibiotic tolerance plays a critical role in transitioning from an acute to chronic infection that is difficult to eradicate with antibiotics alone. IMPORTANCE Surgical infections are one of the most common types of infections encountered in a hospital. Staphylococcus aureus is the most common pathogen associated with this infection. These infections are resilient and difficult to eradicate, as the bacteria form biofilm, a community of bacteria held together by an extracellular matrix. Compared to bacteria that are planktonic, bacteria in a biofilm are more resistant to antibiotics. The mechanism behind how bacteria develop this resistance and establish a chronic infection is unknown. We demonstrate that mazEF, a toxin-antitoxin gene, inhibits biofilm formation and promotes biofilm antibiotic tolerance which allows S. aureus to transition from an acute to chronic infection that cannot be eradicated with antibiotics but is less virulent. This gene not only makes the bacteria more tolerant to antibiotics but makes the bacteria more tolerant to the host.

scholarly journals The Toxin Antitoxin MazEF DrivesStaphylococcus aureusChronic Infection

2019 ◽  
Author(s):  
Dongzhu Ma ◽  
Jonathan B. Mandell ◽  
Niles P. Donegan ◽  
Ambrose L. Cheung ◽  
Wanyan Ma ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Chronic Infection ◽  
Critical Role ◽  
Antimicrobial Treatment ◽  
Antibiotic Tolerance ◽  
Chronic Infections ◽  
Biofilm Growth ◽  
Increased Risk

AbstractStaphylococcus aureusis the major organism responsible for surgical implant infections. Antimicrobial treatment of these infections often fails leading to expensive surgical intervention and increased risk of mortality to the patient. The challenge in treating these infections is associated with the high tolerance ofS. aureusbiofilm to antibiotics. MazEF, a toxin-antitoxin system, is thought to be an important regulator of this phenotype, but its physiological function inS. aureusis controversial. Here, we examined the role of MazEF in developing chronic infections by comparing growth and antibiotic tolerance phenotypes in threeS. aureusstrains to their corresponding strains with disruption ofmazFexpression. Strains lackingmazFproduction showed increased biofilm growth, and decreased biofilm antibiotic tolerance. Deletion oficaADBCin themazF::tn background suppressed the growth phenotype observed withmazF-disrupted strains, suggesting the phenotype wasica-dependent. We confirmed these phenotypes in our murine animal model. Loss ofmazFresulted in increased bacterial burden and decreased survival rate compared to its wild-type strain demonstrating that loss of themazFgene caused an increase inS. aureusvirulence. Although lack ofmazFgene expression increasedS. aureusvirulence, it was more susceptible to antibioticsin vivo. Combined, the ability ofmazFto inhibit biofilm formation and promote biofilm antibiotic tolerance plays a critical role in transitioning from an acute to chronic infection that is difficult to eradicate with antibiotics alone.ImportanceSurgical infections are one of the most common types of infections obtained in a hospital.Staphylococcus aureusis the most common pathogen associated with this infection. These infections are resilient and difficult to eradicate as the bacteria form a biofilm, a community of bacteria held together by an extracellular matrix. Compared to bacteria floating in liquid, bacteria in a biofilm are more resistant to antibiotics. The mechanism behind how bacteria develop this resistance and establish a chronic infection is unknown. We demonstrate thatmazEF, a toxin-antitoxin gene, inhibits biofilm formation and promotes biofilm antibiotic tolerance which allowsS. aureusto transition from an acute to chronic infection that cannot be eradicated with antibiotics but is less virulent. This gene not only makes the bacteria more tolerant to antibiotics but makes the bacteria more tolerant to the host.

scholarly journals Entropically driven aggregation of bacteria by host polymers promotes antibiotic tolerance inPseudomonas aeruginosa

2018 ◽  
Vol 115 (42) ◽  
pp. 10780-10785 ◽  
Author(s):  
Patrick R. Secor ◽  
Lia A. Michaels ◽  
Anina Ratjen ◽  
Laura K. Jennings ◽  
Pradeep K. Singh
Keyword(s):  
Biofilm Formation ◽  
Chronic Infection ◽  
Bacterial Infections ◽  
Genotoxic Stress ◽  
Antibiotic Tolerance ◽  
Key Factors ◽  
Chronic Infections ◽  
New Therapeutic Approaches ◽  
Bacterial Aggregation

Bacteria causing chronic infections are generally observed living in cell aggregates suspended in polymer-rich host secretions, and bacterial phenotypes induced by aggregated growth may be key factors in chronic infection pathogenesis. Bacterial aggregation is commonly thought of as a consequence of biofilm formation; however the mechanisms producing aggregation in vivo remain unclear. Here we show that polymers that are abundant at chronic infection sites cause bacteria to aggregate by the depletion aggregation mechanism, which does not require biofilm formation functions. Depletion aggregation is mediated by entropic forces between uncharged or like-charged polymers and particles (e.g., bacteria). Our experiments also indicate that depletion aggregation of bacteria induces marked antibiotic tolerance that was dependent on the SOS response, a stress response activated by genotoxic stress. These findings raise the possibility that targeting conditions that promote depletion aggregation or mechanisms of depletion-mediated tolerance could lead to new therapeutic approaches to combat chronic bacterial infections.

scholarly journals Evaluation of Antibiotics Active against Methicillin-Resistant Staphylococcus aureus Based on Activity in an Established Biofilm

2016 ◽  
Vol 60 (10) ◽  
pp. 5688-5694 ◽  
Author(s):  
Daniel G. Meeker ◽  
Karen E. Beenken ◽  
Weston B. Mills ◽  
Allister J. Loughran ◽  
Horace J. Spencer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Limit Of Detection ◽  
Relative Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Comparable Activity ◽  
Antibiotic Delivery

ABSTRACTWe usedin vitroandin vivomodels of catheter-associated biofilm formation to compare the relative activity of antibiotics effective against methicillin-resistantStaphylococcus aureus(MRSA) in the specific context of an established biofilm. The results demonstrated that, underin vitroconditions, daptomycin and ceftaroline exhibited comparable activity relative to each other and greater activity than vancomycin, telavancin, oritavancin, dalbavancin, or tigecycline. This was true when assessed using established biofilms formed by the USA300 methicillin-resistant strain LAC and the USA200 methicillin-sensitive strain UAMS-1. Oxacillin exhibited greater activity against UAMS-1 than LAC, as would be expected, since LAC is an MRSA strain. However, the activity of oxacillin was less than that of daptomycin and ceftaroline even against UAMS-1. Among the lipoglycopeptides, telavancin exhibited the greatest overall activity. Specifically, telavancin exhibited greater activity than oritavancin or dalbavancin when tested against biofilms formed by LAC and was the only lipoglycopeptide capable of reducing the number of viable bacteria below the limit of detection. With biofilms formed by UAMS-1, telavancin and dalbavancin exhibited comparable activity relative to each other and greater activity than oritavancin. Importantly, ceftaroline was the only antibiotic that exhibited greater activity than vancomycin when testedin vivoin a murine model of catheter-associated biofilm formation. These results emphasize the need to consider antibiotics other than vancomycin, most notably, ceftaroline, for the treatment of biofilm-associatedS. aureusinfections, including by the matrix-based antibiotic delivery methods often employed for local antibiotic delivery in the treatment of these infections.

scholarly journals Suppression of the Inflammatory Immune Response Prevents the Development of Chronic Biofilm Infection Due to Methicillin-Resistant Staphylococcus aureus

2011 ◽  
Vol 79 (12) ◽  
pp. 5010-5018 ◽  
Author(s):  
Ranjani Prabhakara ◽  
Janette M. Harro ◽  
Jeff G. Leid ◽  
Achsah D. Keegan ◽  
Megan L. Prior ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Chronic Infection ◽  
Treg Cells ◽  
Interleukin 4 ◽  
Infection Rates ◽  
Implant Infection ◽  
Content Type ◽  
Cytokine Levels ◽  
Prosthetic Implant

ABSTRACTStaphylococcus aureusis a common cause of prosthetic implant infections, which can become chronic due to the ability ofS. aureusto grow as a biofilm. Little is known about adaptive immune responses to these infectionsin vivo. We hypothesized thatS. aureuselicits inflammatory Th1/Th17 responses, associated with biofilm formation, instead of protective Th2/Treg responses. We used an adapted mouse model of biofilm-mediated prosthetic implant infection to determine chronic infection rates, Treg cell frequencies, and local cytokine levels in Th1-biased C57BL/6 and Th2-biased BALB/c mice. All C57BL/6 mice developed chronicS. aureusimplant infection at all time points tested. However, over 75% of BALB/c mice spontaneously cleared the infection without adjunctive therapy and demonstrated higher levels of Th2 cytokines and anti-inflammatory Treg cells. When chronic infection rates in mice deficient in the Th2 cytokine interleukin-4 (IL-4) via STAT6 mutation in a BALB/c background were assessed, the mice were unable to clear theS. aureusimplant infection. Additionally, BALB/c mice depleted of Treg cells via an anti-CD25 monoclonal antibody (MAb) were also unable to clear the infection. In contrast, the C57BL/6 mice that were susceptible to infection were able to eliminateS. aureusbiofilm populations on infected intramedullary pins once the Th1 and Th17 responses were diminished by MAb treatment with anti-IL-12 p40. Together, these results indicate that Th2/Treg responses are mechanisms of protection against chronicS. aureusimplant infection, as opposed to Th1/Th17 responses, which may play a role in the development of chronic infection.

scholarly journals Gel-Entrapped Staphylococcus aureus Bacteria as Models of Biofilm Infection Exhibit Growth in Dense Aggregates, Oxygen Limitation, Antibiotic Tolerance, and Heterogeneous Gene Expression

2016 ◽  
Vol 60 (10) ◽  
pp. 6294-6301 ◽  
Author(s):  
Breana Pabst ◽  
Betsey Pitts ◽  
Ellen Lauchnor ◽  
Philip S. Stewart
Keyword(s):  
Staphylococcus Aureus ◽  
Fluorescent Protein ◽  
Specific Growth ◽  
Matrix Material ◽  
Antibiotic Tolerance ◽  
Glass Capillary ◽  
Host Matrix ◽  
Content Type ◽  
Biofilm Infection

ABSTRACTAn experimental model that mimicked the structure and characteristics ofin vivobiofilm infections, such as those occurring in the lung or in dermal wounds where no biomaterial surface is present, was developed. In these infections, microbial biofilm forms as cell aggregates interspersed in a layer of mucus or host matrix material. This structure was modeled by filling glass capillary tubes with an agarose gel that had been seeded withStaphylococcus aureusbacteria and then incubating the gel biofilm in medium for up to 30 h. Confocal microscopy showed that the bacteria formed in discrete pockets distributed throughout the gel matrix. These aggregates enlarged over time and also developed a size gradient, with the clusters being larger near the nutrient- and oxygen-supplied interface and smaller at greater depths. Bacteria entrapped in gels for 24 h grew slowly (specific growth rate, 0.06 h−1) and were much less susceptible to oxacillin, minocycline, or ciprofloxacin than planktonic cells. Microelectrode measurements showed that the oxygen concentration decreased with depth into the gel biofilm, falling to values less than 3% of air saturation at depths of 500 μm. An anaerobiosis-responsive green fluorescent protein reporter gene for lactate dehydrogenase was induced in the region of the gel where the measured oxygen concentrations were low, confirming biologically relevant hypoxia. These results show that the gel biofilm model captures key features of biofilm infection in mucus or compromised tissue: formation of dense, distinct aggregates, reduced specific growth rates, local hypoxia, and antibiotic tolerance.

scholarly journals Tissue Plasminogen Activator Coating on Implant Surfaces Reduces Staphylococcus aureus Biofilm Formation

2015 ◽  
Vol 82 (1) ◽  
pp. 394-401 ◽  
Author(s):  
Jakub Kwiecinski ◽  
Manli Na ◽  
Anders Jarneborn ◽  
Gunnar Jacobsson ◽  
Marijke Peetermans ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Content Type ◽  
Tissue Plasminogen

ABSTRACTStaphylococcus aureusbiofilm infections of indwelling medical devices are a major medical challenge because of their high prevalence and antibiotic resistance. As fibrin plays an important role inS. aureusbiofilm formation, we hypothesize that coating of the implant surface with fibrinolytic agents can be used as a new method of antibiofilm prophylaxis. The effect of tissue plasminogen activator (tPA) coating onS. aureusbiofilm formation was tested within vitromicroplate biofilm assays and anin vivomouse model of biofilm infection. tPA coating efficiently inhibited biofilm formation by variousS. aureusstrains. The effect was dependent on plasminogen activation by tPA, leading to subsequent local fibrin cleavage. A tPA coating on implant surfaces prevented both early adhesion and later biomass accumulation. Furthermore, tPA coating increased the susceptibility of biofilm infections to antibiotics.In vivo, significantly fewer bacteria were detected on the surfaces of implants coated with tPA than on control implants from mice treated with cloxacillin. Fibrinolytic coatings (e.g., with tPA) reduceS. aureusbiofilm formation bothin vitroandin vivo, suggesting a novel way to prevent bacterial biofilm infections of indwelling medical devices.

scholarly journals Oral Administration of the Broad-Spectrum Antibiofilm Compound Toremifene Inhibits Candida albicans and Staphylococcus aureus Biofilm FormationIn Vivo

2014 ◽  
Vol 58 (12) ◽  
pp. 7606-7610 ◽  
Author(s):  
Kaat De Cremer ◽  
Nicolas Delattin ◽  
Katrijn De Brucker ◽  
Annelies Peeters ◽  
Soña Kucharíková ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Candida Albicans ◽  
Broad Spectrum ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Candida Krusei ◽  
Content Type ◽  
And Staphylococcus Aureus

ABSTRACTWe here report on thein vitroactivity of toremifene to inhibit biofilm formation of different fungal and bacterial pathogens, includingCandida albicans,Candida glabrata,Candida dubliniensis,Candida krusei,Pseudomonas aeruginosa,Staphylococcus aureus, andStaphylococcus epidermidis. We validated thein vivoefficacy of orally administered toremifene againstC. albicans and S. aureusbiofilm formation in a rat subcutaneous catheter model. Combined, our results demonstrate the potential of toremifene as a broad-spectrum oral antibiofilm compound.

scholarly journals In VivoMonitoring of Staphylococcus aureus Biofilm Infections and Antimicrobial Therapy by [18F]Fluoro-Deoxyglucose–MicroPET in a Mouse Model

2014 ◽  
Vol 58 (11) ◽  
pp. 6660-6667 ◽  
Author(s):  
Victoria Garrido ◽  
María Collantes ◽  
Montserrat Barberán ◽  
Iván Peñuelas ◽  
Javier Arbizu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mouse Model ◽  
Regional Lymph Node ◽  
Strain Differences ◽  
Antimicrobial Treatment ◽  
Matrix Composition ◽  
Content Type ◽  
New Therapeutic Approaches ◽  
Image Technique

ABSTRACTA mouse model was developed forin vivomonitoring of infection and the effect of antimicrobial treatment againstStaphylococcus aureusbiofilms, using the [18F]fluoro-deoxyglucose–MicroPET ([18F]FDG-MicroPET) image technique. In the model, sealed Vialon catheters were briefly precolonized withS. aureusstrains ATCC 15981 or V329, which differ in cytotoxic properties and biofilm matrix composition. After subcutaneous implantation of catheters in mice, theS. aureusstrain differences found in bacterial counts and the inflammatory reaction triggered were detected by the regular bacteriological and histological procedures and also by [18F]FDG-MicroPET image signal intensity determinations in the infection area and regional lymph node. Moreover, [18F]FDG-MicroPET imaging allowed the monitoring of the rifampin treatment effect, identifying the periods of controlled infection and those of reactivated infection due to the appearance of bacteria naturally resistant to rifampin. Overall, the mouse model developed may be useful for noninvasivein vivodeterminations in studies onS. aureusbiofilm infections and assessment of new therapeutic approaches.

scholarly journals Anthranilate Acts as a Signal to Modulate Biofilm Formation, Virulence, and Antibiotic Tolerance of Pseudomonas aeruginosa and Surrounding Bacteria

2022 ◽  
Author(s):  
Hyeon-Ji Hwang ◽  
Xi-Hui Li ◽  
Soo-Kyoung Kim ◽  
Joon-Hee Lee
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Chronic Infection ◽  
Antibiotic Tolerance ◽  
Content Type ◽  
Before And After

Pseudomonas aeruginosa is a notorious pathogen with high antibiotic resistance, strong virulence, and ability to cause biofilm-mediated chronic infection. We found that these characteristics change profoundly before and after the time when anthranilate is produced as an “anthranilate peak”.

scholarly journals Breaking the Vicious Cycle of Antibiotic Killing and Regrowth of Biofilm-ResidingPseudomonas aeruginosa

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Mathias Müsken ◽  
Vinay Pawar ◽  
Timo Schwebs ◽  
Heike Bähre ◽  
Sebastian Felgner ◽  
...  
Keyword(s):  
Treatment Success ◽  
Antimicrobial Treatment ◽  
Vicious Cycle ◽  
Chronic Infections ◽  
Treatment Protocols ◽  
Content Type ◽  
Treatment Regimens ◽  
Biofilm Bacteria ◽  
Time Required

ABSTRACTBiofilm-residing bacteria embedded in an extracellular matrix are protected from diverse physicochemical insults. In addition to the general recalcitrance of biofilm bacteria, high bacterial loads in biofilm-associated infections significantly diminish the efficacy of antimicrobials due to a low per-cell antibiotic concentration. Accordingly, present antimicrobial treatment protocols that have been established to serve the eradication of acute infections fail to clear biofilm-associated chronic infections. In the present study, we applied automated confocal microscopy onPseudomonas aeruginosato monitor dynamic killing of biofilm-grown bacteria by tobramycin and colistin in real time. We revealed that the time required for surviving bacteria to repopulate the biofilm could be taken as a measure for effectiveness of the antimicrobial treatment. It depends on the (i) nature and concentration of the antibiotic, (ii) duration of antibiotic treatment, (iii) application as monotherapy or combination therapy, and (iv) interval of drug administration. The vicious cycle of killing and repopulation of biofilm bacteria could also be broken in anin vivomodel system by applying successive antibiotic dosages at intervals that do not allow full reconstitution of the biofilm communities. Treatment regimens that consider the important aspects of antimicrobial killing kinetics bear the potential to improve control of biofilm regrowth. This is an important and underestimated factor that is bound to ensure sustainable treatment success of chronic infections.

Sign in / Sign up

Export Citation Format

Share Document