The effect of sublethal heating on Staphylococcus aureus at different physiological ages

1974 ◽  
Vol 20 (5) ◽  
pp. 765-768 ◽  
Author(s):  
Andre Hurst ◽  
Ashton Hughes ◽  
David L. Collins-Thompson
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Heat Resistance ◽  
Growth Cycle ◽  
High Salt ◽  
Early Stationary Phase ◽  
Heat Injury ◽  
The Difference

Sublethal heat injury was measured by the difference in the numbers of colonies developing on trypticase soy agar and trypticase soy agar containing 7.5% NaCl. This difference was largest with late logarithmic and early stationary phase cells because, at this stage, cells had a greatly increased heat resistance. In contrast, the ability to form colonies on high salt agar after sublethal heating varied little during the growth cycle.

Protection Against Heat-Injury in Staphylococcus aureus by Solutes

1982 ◽  
Vol 45 (1) ◽  
pp. 54-58 ◽  
Author(s):  
J. L. SMITH ◽  
R. C. BENEDICT ◽  
S. A. PALUMBO
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Acetate ◽  
Sodium Citrate ◽  
Ground Beef ◽  
Magnesium Ion ◽  
Ion Leakage ◽  
Distilled Water ◽  
Heat Injury ◽  
Absorbing Materials ◽  
The Difference

The effect of solutes on heat-injury in Staphylococcus aureus 196E was studied in 25% ground beef (GB) slurry or distilled water equilibrated at 49 C. Exposure to 49 C for 90 min resulted in a 3–4 log cycle increase in injured cells. The number of injured cells was the difference between bacterial counts on tryptic soy agar (TSA) + 1% pyruvate and TSA + 9% NaCl. Increasing levels of NaCl (1–9%) added to GB slurry gave increasing protection against heat-injury and resulted in a decrease in the number of injured S. aureus; glycerol and sucrose had a similar effect. At 0.85 M (equivalent to 5% NaCl), other compounds such as sodium citrate, KCl, NaNO3, Na2SO4, Na2HPO4, NH4Cl, CaCl2, and LiCl were more effective than NaCl in protecting against heat injury; sodium acetate, MgSO4, NaI, MnCl2, MgCl2, NaBr, NaH2PO4, and KI were less effective than NaCl. In the presence of 5% NaCl, it was necessary to raise the temperature from 49 to 55 C to obtain significant heat-injury to S. aureus. Addition of NaCl prevented the leakage of UV-absorbing materials and decreased the extent of magnesium ion leakage from heat-injured staphylococci.

scholarly journals 6S RNA regulation of relA alters ppGpp levels in early stationary phase

Microbiology ◽  
2010 ◽  
Vol 156 (12) ◽  
pp. 3791-3800 ◽  
Author(s):  
Amy T. Cavanagh ◽  
Pete Chandrangsu ◽  
Karen M. Wassarman
Keyword(s):  
Amino Acid ◽  
Stationary Phase ◽  
Regulation Of Transcription ◽  
Early Stationary Phase ◽  
Rna Regulation ◽  
Global Regulators ◽  
Expression Of Genes ◽  
Non Coding Rna ◽  
6S Rna ◽  
Altered Regulation

6S RNA is a small, non-coding RNA that interacts directly with σ 70-RNA polymerase and regulates transcription at many σ 70-dependent promoters. Here, we demonstrate that 6S RNA regulates transcription of relA, which encodes a ppGpp synthase. The 6S RNA-dependent regulation of relA expression results in increased ppGpp levels during early stationary phase in cells lacking 6S RNA. These changes in ppGpp levels, although modest, are sufficient to result in altered regulation of transcription from σ 70-dependent promoters sensitive to ppGpp, including those promoting expression of genes involved in amino acid biosynthesis and rRNA. These data place 6S RNA as another player in maintaining appropriate gene expression as cells transition into stationary phase. Independent of this ppGpp-mediated 6S RNA-dependent regulation, we also demonstrate that in later stationary phase, 6S RNA continues to downregulate transcription in general, and specifically at a subset of the amino acid promoters, but through a mechanism that is independent of ppGpp and which we hypothesize is through direct regulation. In addition, 6S RNA-dependent regulation of σ S activity is not mediated through observed changes in ppGpp levels. We suggest a role for 6S RNA in modulating transcription of several global regulators directly, including relA, to downregulate expression of key pathways in response to changing environmental conditions.

scholarly journals Bactericidal Action of Daptomycin against Stationary-Phase and Nondividing Staphylococcus aureus Cells

2007 ◽  
Vol 51 (12) ◽  
pp. 4255-4260 ◽  
Author(s):  
Carmela T. M. Mascio ◽  
Jeff D. Alder ◽  
Jared A. Silverman
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Bactericidal Activity ◽  
Direct Action ◽  
Metabolic Inhibitor ◽  
Log Reduction ◽  
Joint Infections ◽  
Prosthetic Joint ◽  
Prosthetic Joint Infections ◽  
Lipopeptide Antibiotic

ABSTRACT Most antibiotics with bactericidal activity require that the bacteria be actively dividing to produce rapid killing. However, in many infections, such as endocarditis, prosthetic joint infections, and infected embedded catheters, the bacteria divide slowly or not at all. Daptomycin is a lipopeptide antibiotic with a distinct mechanism of action that targets the cytoplasmic membrane of gram-positive organisms, including Staphylococcus aureus. Daptomycin is rapidly bactericidal against exponentially growing bacteria (a 3-log reduction in 60 min). The objectives of this study were to determine if daptomycin is bactericidal against nondividing S. aureus and to quantify the extent of the bactericidal activity. In high-inoculum methicillin-sensitive S. aureus cultures in stationary phase (1010 CFU/ml), daptomycin displayed concentration-dependent bactericidal activity, requiring 32 μg/ml to achieve a 3-log reduction. In a study comparing several antibiotics at 100 μg/ml, daptomycin demonstrated faster bactericidal activity than nafcillin, ciprofloxacin, gentamicin, and vancomycin. In experiments where bacterial cell growth was halted by the metabolic inhibitor carbonyl cyanide m-chlorophenylhydrazone or erythromycin, daptomycin (10 μg/ml) achieved the bactericidal end point (a 3-log reduction) within 2 h. In contrast, ciprofloxacin (10 μg/ml) did not produce bactericidal activity. Daptomycin (2 μg/ml) remained bactericidal against cold-arrested S. aureus, which was protected from the actions of ciprofloxacin and nafcillin. The data presented here suggest that, in contrast to that of other classes of antibiotics, the bactericidal activity of daptomycin does not require cell division or active metabolism, most likely as a consequence of its direct action on the bacterial membrane.

scholarly journals Inactivation of TCA cycle enhances Staphylococcus aureus persister cell formation in stationary phase

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ying Wang ◽  
Martin Saxtorph Bojer ◽  
Shilpa Elizabeth George ◽  
Zhihao Wang ◽  
Peter Ruhdal Jensen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Cell Formation ◽  
Tca Cycle ◽  
Persister Cell

scholarly journals Biofilm/Persister/Stationary Phase Bacteria Cause More Severe Disease Than Log Phase Bacteria – II Infection with Persister Forms of Staphylococcus aureus Causes a Chronic Persistent Skin Infection with More Severe Lesion that Takes Longer to Heal and is not Eradicated by the Current Recommended Treatment in Mice

2018 ◽  
Author(s):  
Rebecca Yee ◽  
Yuting Yuan ◽  
Cory Brayton ◽  
Andreina Tarff Leal ◽  
Jie Feng ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Skin Infection ◽  
Bacterial Load ◽  
Mouse Skin ◽  
Infection Model ◽  
Persister Cells ◽  
Persistent Infections ◽  
Recommended Treatment ◽  
Biofilm Bacteria

AbstractStaphylococcus aureus is an opportunistic pathogen that can cause persistent infections clinically. Treatment for chronic S. aureus infections ranges from at least one week to several months and such infections are prone to relapse likely due to the presence of persistent forms of bacteria such as persister cells. Persister cells, which are bacterial cells that become dormant under stress conditions, can be isolated in vitro but their clinical significance in in vivo infections are largely unclear. Here, we evaluated S. aureus persistent forms using stationary phase cultures and biofilm bacteria (enriched in persisters) in comparison with log phase cultures in terms of their ability to cause disease in a mouse skin infection model. Surprisingly, we found that infection of mice with stationary phase cultures and biofilm bacteria produced a more severe chronic skin infection with more pronounced lesions which took longer to heal than log phase (actively growing) cultures. After two week infection, the bacterial load and skin tissue pathology, as determined by hyperplasia, immune cell infiltration, and crust/lesion formation, of mice infected with the more persistent forms (e.g. stationary phase bacteria and biofilm bacteria) were greater than mice infected with log phase bacteria. Using our persistent infection mouse model, we showed that the clinically recommended treatment for recurrent S. aureus skin infection, doxycycline + rifampin, was not effective in eradicating the bacteria in the treatment study, despite reducing lesion sizes and pathology in infected mice. Analogous findings were also observed in a Caenorhabditis elegans model, where S.aureus stationary phase cultures caused a greater mortality than log phase culture as early as two days post-infection. Thus, we established a new model for chronic persistent infections using persister bacteria that could serve as a relevant model to evaluate therapeutic options for persistent infections in general. Our findings connect persisters with persistent infections, have implications for understanding disease pathogenesis, and are likely to be broadly valid for other pathogens.

Associations Between Cellular Levels of ATP and Prodigiosin Pigment Throughout the Growth Cycle of Serratia marcescens

2021 ◽  
Author(s):  
Pryce L. Haddix
Keyword(s):  
Stationary Phase ◽  
Serratia Marcescens ◽  
Stationary Phases ◽  
Growth Cycle ◽  
High Density ◽  
High Rate ◽  
Lag Phase ◽  
Positive Role ◽  
Atp Production ◽  
Density Growth

ABSTRACT Serratia marcescens is a prolific producer of the red, membrane-associated pigment prodigiosin. Earlier work has established both a positive role for prodigiosin in ATP production during population lag phase and a negative role during high-rate, low cell density growth. This study uses the growth rate and growth phase modulation afforded by chemostat culture to extend prodigiosin functional analysis to the high density and stationary phases. Cellular levels of prodigiosin were positively associated with cellular levels of ATP during high-density growth, and artificial pigment induction during this phase increased cellular ATP. Following peak high density ATP per cell, early stationary phase enabled significant population growth while prodigiosin levels remained high and ATP declined. During late stationary phase, ATP per cell was positively associated with prodigiosin per cell while both declined during continued growth. These results provide correlational evidence for multiple effects of prodigiosin pigment on ATP production throughout the growth cycle. Earlier work and the data presented here enable formulation of a working model for the oscillating relationships between cellular levels of ATP and prodigiosin during batch culture.

scholarly journals The Nature of Antibacterial Adaptive Immune Responses against Staphylococcus aureus Is Dependent on the Growth Phase and Extracellular Peptidoglycan

2019 ◽  
Vol 88 (1) ◽  
Author(s):  
Payal P. Balraadjsing ◽  
Lisbeth D. Lund ◽  
Yuri Souwer ◽  
Sebastian A. J. Zaat ◽  
Hanne Frøkiær ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
T Cell ◽  
Stationary Phase ◽  
Growth Phase ◽  
Cell Response ◽  
Th17 Cell ◽  
Exponential Phase ◽  
Th1 Cell ◽  
Content Type

ABSTRACT Staphylococcus aureus has evolved different strategies to evade the immune response, which play an important role in its pathogenesis. The bacteria express and shed various cell wall components and toxins during different stages of growth that may affect the protective T cell responses to extracellular and intracellular S. aureus. However, if and how the dendritic cell (DC)-mediated T cell response against S. aureus changes during growth of the bacterium remain elusive. In this study, we show that exponential-phase (EP) S. aureus bacteria were endocytosed very efficiently by human DCs, and these DCs strongly promoted production of the T cell polarizing factor interleukin-12 (IL-12). In contrast, stationary-phase (SP) S. aureus bacteria were endocytosed less efficiently by DCs, and these DCs produced small amounts of IL-12. The high level of IL-12 production induced by EP S. aureus led to the development of a T helper 1 (Th1) cell response, which was inhibited after neutralization of IL-12. Furthermore, preincubation with the staphylococcal cell wall component peptidoglycan (PGN), characteristically shed during the exponential growth phase, modulated the DC response to EP S. aureus. PGN preincubation appeared to inhibit IL-12p35 expression, leading to downregulation of IL-12 and an increase of IL-23 production by DCs, enhancing Th17 cell development. Taken together, our data indicate that exponential-phase S. aureus bacteria induce a stronger IL-12-dependent Th1 cell response than stationary-phase S. aureus and that this Th1 cell response shifted toward a Th17 cell response in the presence of PGN.

scholarly journals Association of a Disrupted Dipping Pattern of Blood Pressure with Progression of Renal Injury during the Development of Salt-Dependent Hypertension in Rats

2020 ◽  
Vol 21 (6) ◽  
pp. 2248 ◽  
Author(s):  
Abu Sufiun ◽  
Asadur Rahman ◽  
Kazi Rafiq ◽  
Yoshihide Fujisawa ◽  
Daisuke Nakano ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Circadian Rhythm ◽  
Renal Injury ◽  
Tissue Injury ◽  
Renal Tissue ◽  
High Salt ◽  
Hypertensive Rats ◽  
High Salt Diet ◽  
Salt Diet ◽  
The Difference

The aim of the present study is to investigate whether a disruption of the dipping pattern of blood pressure (BP) is associated with the progression of renal injury in Dahl salt-sensitive (DSS) hypertensive rats. Seven-week-old DSS rats were fed a high salt diet (HSD; 8% NaCl) for 10 weeks, followed by a transition to a normal salt diet (NSD; 0.3% NaCl) for 4 weeks. At baseline, NSD-fed DSS rats showed a dipper-type circadian rhythm of BP. By contrast, HSD for 5 days caused a significant increase in the difference between the active and inactive periods of BP with an extreme dipper type of BP, while proteinuria and renal tissue injury were not observed. Interestingly, HSD feeding for 10 weeks developed hypertension with a non-dipper pattern of BP, which was associated with obvious proteinuria and renal tissue injury. Four weeks after switching to an NSD, BP and proteinuria were significantly decreased, and the BP circadian rhythm returned to the normal dipper pattern. These data suggest that the non-dipper pattern of BP is associated with the progression of renal injury during the development of salt-dependent hypertension.

scholarly journals Pharyngeal Detection of Staphylococcus aureus as a Possible Factor Related to Disgust Sensitivity in Humans

2020 ◽  
Vol 17 (21) ◽  
pp. 8286
Author(s):  
Agnieszka Żelaźniewicz ◽  
Judyta Nowak-Kornicka ◽  
Renata Figura ◽  
Agata Groyecka-Bernard ◽  
Piotr Sorokowski ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Statistical Significance ◽  
Disgust Sensitivity ◽  
Significance Level ◽  
Body Adiposity ◽  
Behavioral Avoidance ◽  
Sexual Disgust ◽  
Scale Levels ◽  
The Difference ◽  
The Cost

Disgust triggers behavioral avoidance of pathogen-carrying and fitness-reducing agents. However, because of the cost involved, disgust sensitivity should be flexible, varying as a function of an individual’s immunity. Asymptomatic colonization with Staphylococcus aureus often results from weakened immunity and is a potential source of subsequent infections. In this study, we tested if pharyngeal colonization with S. aureus, evaluated based on a single swab collection, is related to an individual’s disgust sensitivity, measured with the Three Domain Disgust Scale. Levels of immunomodulating hormones (cortisol and testosterone), general health, and body adiposity were controlled. Women (N = 95), compared to men (N = 137), displayed higher sexual disgust sensitivity, but the difference between individuals with S. aureus and without S. aureus was significant only in men, providing support for prophylactic hypothesis, explaining inter-individual differences in disgust sensitivity. Men (but not women) burdened with asymptomatic S. aureus presence in pharynx exhibit higher pathogen disgust (p = 0.04) compared to individuals in which S. aureus was not detected. The positive relationship between the presence of the pathogen and sexual disgust was close to the statistical significance level (p = 0.06), and S. aureus colonization was not related with moral disgust domain.

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