The Virulence Potential of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Cultured from the Airways of Cystic Fibrosis Patients

Staphylococcus aureus is one of the most common pathogens that infects the airways of patients with cystic fibrosis (CF) and contributes to respiratory failure. Recently, livestock-associated methicillin-resistant S. aureus (LA-MRSA), usually cultured in farm animals, were detected in CF airways. Although some of these strains are able to establish severe infections in humans, there is limited knowledge about the role of LA-MRSA virulence in CF lung disease. To address this issue, we analyzed LA-MRSA, hospital-associated (HA-) MRSA and methicillin-susceptible S. aureus (MSSA) clinical isolates recovered early in the course of airway infection and several years after persistence in this hostile environment from pulmonary specimens of nine CF patients regarding important virulence traits such as their hemolytic activity, biofilm formation, invasion in airway epithelial cells, cytotoxicity, and antibiotic susceptibility. We detected that CF LA-MRSA isolates were resistant to tetracycline, more hemolytic and cytotoxic than HA-MRSA, and more invasive than MSSA. Despite the residence in the animal host, LA-MRSA still represent a serious threat to humans, as such clones possess a virulence potential similar or even higher than that of HA-MRSA. Furthermore, we confirmed that S. aureus individually adapts to the airways of CF patients, which eventually impedes the success of antistaphylococcal therapy of airway infections in CF.

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Tomatidine Inhibits Replication of Staphylococcus aureus Small-Colony Variants in Cystic Fibrosis Airway Epithelial Cells

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01468-10 ◽

2011 ◽

Vol 55 (5) ◽

pp. 1937-1945 ◽

Cited By ~ 29

Author(s):

Gabriel Mitchell ◽

Mariza Gattuso ◽

Gilles Grondin ◽

Éric Marsault ◽

Kamal Bouarab ◽

...

Keyword(s):

Cystic Fibrosis ◽

Staphylococcus Aureus ◽

Electron Transport ◽

Epithelial Cells ◽

Airway Epithelial Cells ◽

Plant Secondary Metabolite ◽

Airway Epithelial ◽

Small Colony Variants ◽

Content Type ◽

Small Colony

ABSTRACTSmall-colony variants (SCVs) often are associated with chronicStaphylococcus aureusinfections, such as those encountered by cystic fibrosis (CF) patients. We report here that tomatidine, the aglycon form of the plant secondary metabolite tomatine, has a potent growth inhibitory activity against SCVs (MIC of 0.12 μg/ml), whereas the growth of normalS. aureusstrains was not significantly altered by tomatidine (MIC, >16 μg/ml). The specific action of tomatidine was bacteriostatic for SCVs and was clearly associated with their dysfunctional electron transport system, as the presence of the electron transport inhibitor 4-hydroxy-2-heptylquinoline-N-oxide (HQNO) caused normalS. aureusstrains to become susceptible to tomatidine. Inversely, the complementation of SCVs' respiratory deficiency conferred resistance to tomatidine. Tomatidine provoked a general reduction of macromolecular biosynthesis but more specifically affected the incorporation of radiolabeled leucine in proteins of HQNO-treatedS. aureusat a concentration corresponding to the MIC against SCVs. Furthermore, tomatidine inhibited the intracellular replication of a clinical SCV in polarized CF-like epithelial cells. Our results suggest that tomatidine eventually will find some use in combination therapy with other traditional antibiotics to eliminate persistent forms ofS. aureus.

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WS05.4 The role of airway epithelial cells in the abnormal biosynthesis of specialised pro-resolving lipid mediators in cystic fibrosis

Journal of Cystic Fibrosis ◽

10.1016/s1569-1993(21)00942-5 ◽

2021 ◽

Vol 20 ◽

pp. S9-S10

Author(s):

M. Shum ◽

M. London ◽

M. Briottet ◽

N. Remus ◽

V. Escabasse ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Airway Epithelial Cells ◽

Lipid Mediators ◽

Airway Epithelial

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Tedizolid inhibits MUC5AC production induced by methicillin-resistant Staphylococcus aureus in human airway epithelial cells

Journal of Infection and Chemotherapy ◽

10.1016/j.jiac.2017.04.015 ◽

2017 ◽

Vol 23 (9) ◽

pp. 598-603 ◽

Cited By ~ 1

Author(s):

Kazuaki Takeda ◽

Norihito Kaku ◽

Yoshitomo Morinaga ◽

Kosuke Kosai ◽

Naoki Uno ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Epithelial Cells ◽

Methicillin Resistant Staphylococcus Aureus ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Methicillin Resistant ◽

Human Airway ◽

Human Airway Epithelial Cells

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Methicillin-resistant Staphylococcus aureus urosepsis: A rare complication of neonatal circumcision

SAGE Open Medical Case Reports ◽

10.1177/2050313x20966122 ◽

2020 ◽

Vol 8 ◽

pp. 2050313X2096612

Author(s):

Ahmed Khalil ◽

Eiman Hamid ◽

Khaled Siddiq ◽

Manasik Hassan

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Clinical Course ◽

Rare Complication ◽

Methicillin Resistant ◽

Severe Infections ◽

Neonatal Circumcision

The role of circumcision and its benefits has received increased attention across several disciplines in recent years; however, there is increasing concern that some uncommon complications such as severe infections are being related to post-circumcision. We describe the clinical course of a 14-day-old boy who had Methicillin-resistant Staphylococcus aureus urosepsis after circumcision.

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Comparison of Adhesion and Virulence of Two Predominant Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Clones and Clonal Methicillin-Susceptible S. aureus Isolates

Infection and Immunity ◽

10.1128/iai.01697-07 ◽

2008 ◽

Vol 76 (11) ◽

pp. 5133-5138 ◽

Cited By ~ 18

Author(s):

Hatice Karauzum ◽

Tristan Ferry ◽

Sophie de Bentzmann ◽

Gérard Lina ◽

Michèle Bes ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Airway Epithelial Cells ◽

Sequence Type ◽

Airway Epithelial ◽

Methicillin Resistant ◽

Type Iv ◽

In Vitro Adhesion ◽

A Minor ◽

Hospital Acquired

ABSTRACT The virulence of SCCmec type IV hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates belonging to the major sequence type 8 (ST8 [Lyon clone]) and to a minor upcoming clone, ST5, was compared with that of methicillin-susceptible S. aureus (MSSA) isolates of matching sequence types. In vitro adhesion to human airway epithelial cells (HAECs) as an indicator of dissemination and mortality in a murine sepsis model as an indicator of virulence were evaluated. Ten MRSA isolates and 8 MSSA isolates of ST8 and 8 MRSA isolates and 8 MSSA isolates of ST5 were characterized with respect to multilocus sequence type; agr, spa, and capsule typing; in vitro doubling time; toxin and adhesin gene profiles; and adherence to HAECs. Adherence was significantly lower in the MRSA ST5 group than in the ST8 groups. Infections with MRSA and MSSA isolates ST8 and ST5 were compared. No change in virulence related to the presence of SCCmec was observed, since ST8 but not ST5 caused a significantly lower mortality in its presence. Despite their similar genetic backgrounds, individual clonal MRSA and MSSA isolates were heterogeneous in adherence and virulence. No one of these specific virulence factors determined in vitro was related to mouse mortality. In conclusion, in a bacteremic model, mortality was dependent on the ST and was differentially modulated by SCCmec; within an ST, clonality was not associated with a homogenous outcome.

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Role of epithelial sodium channels in the regulation of lung fluid homeostasis

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00319.2015 ◽

2015 ◽

Vol 309 (11) ◽

pp. L1229-L1238 ◽

Cited By ~ 58

Author(s):

Sadis Matalon ◽

Rafal Bartoszewski ◽

James F. Collawn

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Fetal Lung ◽

Airway Epithelial Cells ◽

Lung Epithelial Cells ◽

Airway Epithelial ◽

Lung Fluid ◽

Lung Epithelial ◽

Distal Lung

In utero, fetal lung epithelial cells actively secrete Cl− ions into the lung air spaces while Na+ ions follow passively to maintain electroneutrality. This process, driven by an electrochemical gradient generated by the Na+-K+-ATPase, is responsible for the secretion of fetal fluid that is essential for normal lung development. Shortly before birth, a significant upregulation of amiloride-sensitive epithelial channels (ENaCs) on the apical side of the lung epithelial cells results in upregulation of active Na+ transport. This process is critical for the reabsorption of fetal lung fluid and the establishment of optimum gas exchange. In the adult lung, active Na+ reabsorption across distal lung epithelial cells limits the degree of alveolar edema in patients with acute lung injury and cardiogenic edema. Cl− ions are transported either paracellularly or transcellularly to preserve electroneutrality. An increase in Cl− secretion across the distal lung epithelium has been reported following an acute increase in left atrial pressure and may result in pulmonary edema. In contrast, airway epithelial cells secrete Cl− through apical cystic fibrosis transmembrane conductance regulator and Ca2+-activated Cl− channels and absorb Na+. Thus the coordinated action of Cl− secretion and Na+ absorption is essential for maintenance of the volume of epithelial lining fluid that, in turn, maximizes mucociliary clearance and facilitates clearance of bacteria and debris from the lungs. Any factor that interferes with Na+ or Cl− transport or dramatically upregulates ENaC activity in airway epithelial cells has been associated with lung diseases such as cystic fibrosis or chronic obstructive lung disease. In this review we focus on the role of the ENaC, the mechanisms involved in ENaC regulation, and how ENaC dysregulation can lead to lung pathology.

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Immunomodulatory Effect of Linezolid on Methicillin-Resistant Staphylococcus aureus Supernatant-Induced MUC5AC Overexpression in Human Airway Epithelial Cells

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02811-13 ◽

2014 ◽

Vol 58 (7) ◽

pp. 4131-4137 ◽

Cited By ~ 6

Author(s):

Norihito Kaku ◽

Katsunori Yanagihara ◽

Yoshitomo Morinaga ◽

Koichi Yamada ◽

Yosuke Harada ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Protein Kinase ◽

Epithelial Cells ◽

Protein Production ◽

Airway Epithelial Cells ◽

Protein Kinase Inhibitors ◽

Immunomodulatory Effect ◽

Airway Epithelial ◽

Major Barrier ◽

Methicillin Resistant

ABSTRACTLinezolid is the first member of the oxazolidinones and is active against drug-resistant Gram-positive pathogens, such as methicillin-resistantStaphylococcus aureus(MRSA). Additionally, linezolid shows an immunomodulatory effect, such as inhibition of inflammatory cytokine production. In this study, we examined the effect of linezolid on MRSA-induced MUC5AC overexpression in airway epithelial cells. In this study, an MRSA supernatant was used to avoid the direct effect of linezolid on MRSA. MUC5AC protein production was significantly increased with a 40-fold dilution of MRSA supernatant. At the mRNA level, MUC5AC gene expression was significantly increased 6 and 9 h after stimulation. In an inhibition study, linezolid significantly reduced MRSA-induced MUC5AC protein and mRNA overexpression at concentrations of 5 and 20 μg/ml, which were the same as the trough and peak concentrations in human epithelial lining fluid. In an analysis of cell signaling, among the mitogen-activated protein kinase inhibitors, only the extracellular signal-regulated protein kinase 1/2 (ERK1/2) inhibitor reduced the MUC5AC protein production to the same level as that of the control; on Western blot analysis, only ERK1/2 was phosphorylated by the MRSA supernatant. In addition, the ERK1/2 phosphorylation was inhibited by linezolid. MUC5AC and MUC5B are the major barrier that traps inhaled microbial organisms, particulates, and foreign irritants. However, in patients with chronic respiratory diseases, pathogen-induced MUC5AC overexpression causes many problems, and control of the overexpression is important. Thus, this study revealed that linezolid showed a direct immunomodulatory effect in airway epithelial cells.

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Staphylococcus aureusBiofilm Growth on Cystic Fibrosis Airway Epithelial Cells Is Enhanced during Respiratory Syncytial Virus Coinfection

mSphere ◽

10.1128/msphere.00341-18 ◽

2018 ◽

Vol 3 (4) ◽

Cited By ~ 16

Author(s):

Megan R. Kiedrowski ◽

Jordan R. Gaston ◽

Brian R. Kocak ◽

Stefanie L. Coburn ◽

Stella Lee ◽

...

Keyword(s):

Cystic Fibrosis ◽

Staphylococcus Aureus ◽

Respiratory Syncytial Virus ◽

Biofilm Formation ◽

Airway Epithelial Cells ◽

Airway Epithelial ◽

Biofilm Growth ◽

Content Type ◽

Syncytial Virus ◽

Polymicrobial Infections

ABSTRACTStaphylococcus aureusis a major cause of chronic respiratory infection in patients with cystic fibrosis (CF). We recently showed thatPseudomonas aeruginosaexhibits enhanced biofilm formation during respiratory syncytial virus (RSV) coinfection on human CF airway epithelial cells (AECs). The impact of respiratory viruses on other bacterial pathogens during polymicrobial infections in CF remains largely unknown. To investigate ifS. aureusbiofilm growth in the CF airways is impacted by virus coinfection, we evaluatedS. aureusgrowth on CF AECs. Initial studies showed an increase inS. aureusgrowth over 24 h, and microscopy revealed biofilm-like clusters of bacteria on CF AECs. Biofilm growth was enhanced when CF AECs were coinfected with RSV, and this observation was confirmed withS. aureusCF clinical isolates. Apical conditioned medium from RSV-infected cells promotedS. aureusbiofilms in the absence of the host epithelium, suggesting that a secreted factor produced during virus infection benefitsS. aureusbiofilms. Exogenous iron addition did not significantly alter biofilm formation, suggesting that it is not likely the secreted factor. We further characterizedS. aureus-RSV coinfection in our model using dual host-pathogen RNA sequencing, allowing us to observe specific contributions ofS. aureusand RSV to the host response during coinfection. Using the dual host-pathogen RNA sequencing approach, we observed increased availability of nutrients from the host and upregulation ofS. aureusgenes involved in growth, protein translation and export, and amino acid metabolism during RSV coinfection.IMPORTANCEThe airways of individuals with cystic fibrosis (CF) are commonly chronically infected, andStaphylococcus aureusis the dominant bacterial respiratory pathogen in CF children. CF patients also experience frequent respiratory virus infections, and it has been hypothesized that virus coinfection increases the severity ofS. aureuslung infections in CF. We investigated the relationship betweenS. aureusand the CF airway epithelium and observed that coinfection with respiratory syncytial virus (RSV) enhancesS. aureusbiofilm growth. However, iron, which was previously found to be a significant factor influencingPseudomonas aeruginosabiofilms during virus coinfection, plays a minor role inS. aureuscoinfections. Transcriptomic analyses provided new insight into how bacterial and viral pathogens alter host defense and suggest potential pathways by which dampening of host responses to one pathogen may favor persistence of another in the CF airways, highlighting complex interactions occurring between bacteria, viruses, and the host during polymicrobial infections.

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Contribution of Staphylococcal Enterotoxin B to Staphylococcus aureus Systemic Infection

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa584 ◽

2020 ◽

Author(s):

Justin S Bae ◽

Fei Da ◽

Ryan Liu ◽

Lei He ◽

Huiying Lv ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Significant Contribution ◽

Systemic Infection ◽

Staphylococcal Enterotoxin ◽

Staphylococcal Enterotoxin B ◽

Methicillin Resistant ◽

Virulence Potential ◽

Infection Models ◽

Enterotoxin B

Abstract Staphylococcal enterotoxin B (SEB), which is produced by the major human pathogen, Staphylococcus aureus, represents a powerful superantigenic toxin and is considered a bioweapon. However, the contribution of SEB to S. aureus pathogenesis has never been directly demonstrated with genetically defined mutants in clinically relevant strains. Many isolates of the predominant Asian community-associated methicillin-resistant S. aureus lineage sequence type (ST) 59 harbor seb, implying a significant role of SEB in the observed hypervirulence of this lineage. We created an isogenic seb mutant in a representative ST59 isolate and assessed its virulence potential in mouse infection models. We detected a significant contribution of seb to systemic ST59 infection that was associated with a cytokine storm. Our results directly demonstrate that seb contributes to S. aureus pathogenesis, suggesting the value of including SEB as a target in multipronged antistaphylococcal drug development strategies. Furthermore, they indicate that seb contributes to fatal exacerbation of community-associated methicillin-resistant S. aureus infection.

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