scholarly journals Proteomic and Membrane Lipid Correlates of Re-duced Host Defense Peptide Susceptibility in a snoD Mutant of Staphylococcus aureus

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 169
Author(s):  
Christian Kohler ◽  
Richard Proctor ◽  
Arnold Bayer ◽  
Michael Yeaman ◽  
Michael Lalk ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Compositional Data ◽  
Insertion Site ◽  
Growth Conditions ◽  
Membrane Lipid ◽  
Anaerobic Growth ◽  
Short Chain ◽  
Aureus Strain ◽  
Branched Chain ◽  
The Impact

We previously described a transposon mutant in Staphylococcus aureus strain SH1000 that exhibited reduced susceptibility to cationic thrombin-induced platelet microbicidal proteins (tPMPs). The transposon insertion site was mapped to the gene snoD, the staphylococcal nuo orthologue. Hence, further studies have been performed to understand how this mutation impacts susceptibility to tPMP, by comparing proteomics profiling and membrane lipid analyses of the parent vs. mutant strains. Surprisingly, the mutant showed differential regulation of only a single protein when cultivated aerobically (FadB), and only a small number of proteins under anaerobic growth conditions (AdhE, DapE, Ddh, Ald1, IlvA1, AgrA, Rot, SA2366, and SA2367). Corresponding to FadB impact on lipid remodeling, membrane fatty acid analyses showed that the snoD mutant contained more short chain anteiso-, but fewer short chain iso-branched chain fatty acids under both aerobic and anaerobic conditions vs. the parental strain. Based upon these proteomic and membrane compositional data, a hypothetical “network” model was developed to explain the impact of the snoD mutation upon tPMP susceptibility.

scholarly journals Staphylococcus aureus Strain USA300 Perturbs Acquisition of Lysosomal Enzymes and Requires Phagosomal Acidification for Survival inside Macrophages

2015 ◽  
Vol 84 (1) ◽  
pp. 241-253 ◽  
Author(s):  
Zachary R. Tranchemontagne ◽  
Ryan B. Camire ◽  
Vanessa J. O'Donnell ◽  
Jessfor Baugh ◽  
Kristin M. Burkholder
Keyword(s):  
Staphylococcus Aureus ◽  
Lysosomal Enzymes ◽  
Intracellular Survival ◽  
Aureus Strain ◽  
Lysosomal Hydrolases ◽  
Content Type ◽  
Multiple Strains ◽  
Virulence Regulator ◽  
The Impact

Methicillin-resistantStaphylococcus aureus(MRSA) causes invasive, drug-resistant skin and soft tissue infections. Reports thatS. aureusbacteria survive inside macrophages suggest that the intramacrophage environment may be a niche for persistent infection; however, mechanisms by which the bacteria might evade macrophage phagosomal defenses are unclear. We examined the fate of theS. aureus-containing phagosome in THP-1 macrophages by evaluating bacterial intracellular survival and phagosomal acidification and maturation and by testing the impact of phagosomal conditions on bacterial viability. Multiple strains ofS. aureussurvived inside macrophages, and in studies using the MRSA USA300 clone, the USA300-containing phagosome acidified rapidly and acquired the late endosome and lysosome protein LAMP1. However, fewer phagosomes containing live USA300 bacteria than those containing dead bacteria associated with the lysosomal hydrolases cathepsin D and β-glucuronidase. Inhibiting lysosomal hydrolase activity had no impact on intracellular survival of USA300 or otherS. aureusstrains, suggesting thatS. aureusperturbs acquisition of lysosomal enzymes. We examined the impact of acidification onS. aureusintramacrophage viability and found that inhibitors of phagosomal acidification significantly impaired USA300 intracellular survival. Inhibition of macrophage phagosomal acidification resulted in a 30-fold reduction in USA300 expression of the staphylococcal virulence regulatoragrbut had little effect on expression ofsarA,saeR, orsigB. Bacterial exposure to acidic pHin vitroincreasedagrexpression. Together, these results suggest thatS. aureussurvives inside macrophages by perturbing normal phagolysosome formation and that USA300 may sense phagosomal conditions and upregulate expression of a key virulence regulator that enables its intracellular survival.

Osmoadaptation by Staphylococcus aureus: Analysis of Several Strains Linked to Food Poisoning Outbreaks

1997 ◽  
Vol 60 (2) ◽  
pp. 139-143 ◽  
Author(s):  
HEATHER A. LOUCH ◽  
MICHELLE L. ECK ◽  
KAREN J. MILLER
Keyword(s):  
Staphylococcus Aureus ◽  
Glycine Betaine ◽  
Food Poisoning ◽  
Growth Conditions ◽  
Aureus Strain ◽  
Resonance Spectroscopy ◽  
Genetic Studies ◽  
Cell Extracts ◽  
Amino Acid Analyzer ◽  
Solute Composition

The authors examined the intracellular solute composition of five strains of Staphylococcus aureus after growth in a medium of low water activity. Organic solutes within cell extracts were analyzed using an amino acid analyzer and nuclear magnetic resonance spectroscopy. Intracellular potassium content was assayed using a potassium-specific electrode. The results showed that the five S. aureus strains accumulated proline and glycine betaine intracellularly under these growth conditions. The levels of accumulated proline and glycine betaine were strikingly similar among the strains, despite differences in salt tolerance. During the course of these experiments it was also found that S. aureus strain RN4220 (a strain commonly used in genetic studies) was selectively impaired in its ability to utilize proline during osmoadaptation at 41°C.

scholarly journals Phenotypic PIA-Dependent Biofilm Production by Clinical Non-Typeable Staphylococcus aureus Is Not Associated with the Intensity of Inflammation in Mammary Gland: A Pilot Study Using Mouse Mastitis Model

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3047
Author(s):  
Jully Gogoi-Tiwari ◽  
Dorji Dorji ◽  
Harish Kumar Tiwari ◽  
Gayatri Shirolkar ◽  
Joshua W. Aleri ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mammary Gland ◽  
Tissue Damage ◽  
Clinical Symptoms ◽  
Mammary Glands ◽  
Aureus Strain ◽  
Mammary Tissue ◽  
Damage Level ◽  
Biofilm Production ◽  
The Impact

Non-typeable (NT) Staphylococcus aureus strains are associated with chronic bovine mastitis. This study investigates the impact of biofilm formation by clinical NT S. aureus on cytokine production and mammary tissue damage by using a mouse mastitis model. Mice infected with two different NT S. aureus strains with strong and weak biofilm forming potential demonstrated identical clinical symptoms (moderate), minimal inflammatory infiltrates, and tissue damage (level 1 histopathological changes) in the mammary glands. However, the S. aureus load in the mammary glands of mice and the level of pro-inflammatory cytokines (IL-1β, IL-6, IL-12, IL-17 and IFN-γ) in serum were significantly higher (p ≤ 0.05) in those infected with the strong biofilm forming NT S. aureus strain. The level of IL-6 in sera samples of these mice was extremely high (15,479.9 ± 532 Pg/mL. Furthermore, these mice died in 24h of post infection compared to 30 h in the weak biofilm forming NT S. aureus infected group. The study demonstrates no association between the strength of PIA (polysaccharide intercellular adhesion)-dependent biofilm production by clinical NT S. aureus and mammary gland pathology in a mouse mastitis model. However, the role of biofilm in the virulence of S. aureus advancing the time of mortality in mice warrants further investigation.

scholarly journals Global Gene Expression in Staphylococcus aureus Biofilms

2004 ◽  
Vol 186 (14) ◽  
pp. 4665-4684 ◽  
Author(s):  
Karen E. Beenken ◽  
Paul M. Dunman ◽  
Fionnuala McAleese ◽  
Daphne Macapagal ◽  
Ellen Murphy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Adaptive Response ◽  
Biofilm Formation ◽  
Global Gene Expression ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Over Expression ◽  
Custom Made

ABSTRACT We previously demonstrated that mutation of the staphylococcal accessory regulator (sarA) in a clinical isolate of Staphylococcus aureus (UAMS-1) results in an impaired capacity to form a biofilm in vitro (K. E. Beenken, J. S. Blevins, and M. S. Smeltzer, Infect. Immun. 71:4206-4211, 2003). In this report, we used a murine model of catheter-based biofilm formation to demonstrate that a UAMS-1 sarA mutant also has a reduced capacity to form a biofilm in vivo. Surprisingly, mutation of the UAMS-1 ica locus had little impact on biofilm formation in vitro or in vivo. In an effort to identify additional loci that might be relevant to biofilm formation and/or the adaptive response required for persistence of S. aureus within a biofilm, we isolated total cellular RNA from UAMS-1 harvested from a biofilm grown in a flow cell and compared the transcriptional profile of this RNA to RNA isolated from both exponential- and stationary-phase planktonic cultures. Comparisons were done using a custom-made Affymetrix GeneChip representing the genomic complement of six strains of S. aureus (COL, N315, Mu50, NCTC 8325, EMRSA-16 [strain 252], and MSSA-476). The results confirm that the sessile lifestyle associated with persistence within a biofilm is distinct by comparison to the lifestyles of both the exponential and postexponential phases of planktonic culture. Indeed, we identified 48 genes in which expression was induced at least twofold in biofilms over expression under both planktonic conditions. Similarly, we identified 84 genes in which expression was repressed by a factor of at least 2 compared to expression under both planktonic conditions. A primary theme that emerged from the analysis of these genes is that persistence within a biofilm requires an adaptive response that limits the deleterious effects of the reduced pH associated with anaerobic growth conditions.

scholarly journals Unprotonated Short-Chain Alkylamines Inhibit Staphylolytic Activity of Lysostaphin in a Wall Teichoic Acid-Dependent Manner

2018 ◽  
Vol 84 (14) ◽  
Author(s):  
Xia Wu ◽  
Seok Joon Kwon ◽  
Domyoung Kim ◽  
Jian Zha ◽  
Mauricio Mora-Pale ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Respiratory Infections ◽  
Teichoic Acid ◽  
Inhibitory Effect ◽  
Short Chain ◽  
Dependent Manner ◽  
Cell Binding ◽  
Wall Teichoic Acid ◽  
Content Type ◽  
The Impact

ABSTRACTLysostaphin (Lst) is a potent bacteriolytic enzyme that killsStaphylococcus aureus, a common bacterial pathogen of humans and animals. With high activity against both planktonic cells and biofilms, Lst has the potential to be used in industrial products, such as commercial cleansers, for decontamination. However, Lst is inhibited in the presence of monoethanolamine (MEA), a chemical widely used in cleaning solutions and pharmaceuticals, and the underlying mechanism of inhibition remains unknown. In this study, we examined the cell binding and killing capabilities of Lst againstS. aureusATCC 6538 in buffered salt solution with MEA at different pH values (7.5 to 10.5) and discovered that only the unprotonated form of MEA inhibited Lst binding to the cell surface, leading to low Lst activity, despite retention of its secondary structure. This reduced enzyme activity could be largely recovered via a reduction in wall teichoic acid (WTA) biosynthesis through tunicamycin treatment, indicating that the suppression of Lst activity was dependent on the presence and amount of WTA. We propose that the decreased cell binding and killing capabilities of Lst are associated with the influence of uncharged MEA on the conformation of WTA. A similar effect was confirmed with other short-chain alkylamines. This study offers new insight into the impact of short-chain alkylamines on both Lst and WTA structure and function and provides guidance for the application of Lst in harsh environments.IMPORTANCELysostaphin (Lst) effectively and selectively killsStaphylococcus aureus, the bacterial culprit of many hospital- and community-acquired skin and respiratory infections and food poisoning. Lst has been investigated in animal models and clinical trials, industrial formulations, and environmental settings. Here, we studied the mechanistic basis of the inhibitory effect of alkylamines, such as monoethanolamine (MEA), a widely used chemical in commercial detergents, on Lst activity, for the potential incorporation of Lst in disinfectant solutions. We have found that protonated MEA has little influence on Lst activity, while unprotonated MEA prevents Lst from binding toS. aureuscells and hence dramatically decreases the enzyme's bacteriolytic efficacy. Following partial removal of the wall teichoic acid, an important component of the bacterial cell envelope, the inhibitory effect of unprotonated MEA on Lst is reduced. This phenomenon can be extended to other short-chain alkylamines. This mechanistic report of the impact of alkylamines on Lst functionality will help guide future applications of Lst in disinfection and decontamination of health-related commercial products.

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