Adaptation to Stress: Biofilms and Small‐Colony Variants

Thompson, Keyata N.; Jefferson, Kimberly K.

doi:10.1002/9781444308464.ch5

Cited by 6 publications

(12 citation statements)

References 155 publications

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“…In addition to the challenges posed by antimicrobial resistance, the treatment of staphylococcal infections is further complicated by a number of strategies that staphylococci have developed, which enable the bacteria to evade the host immune response and the activity of antimicrobials [12,143]. Two strategies, namely the formation of biofilms and the development of smallcolony variants, will be discussed in further detail.…”

Section: Alternate Bacterial Strategies To Circumvent the Action Of Amentioning

confidence: 99%

“…The formation of biofilms affords bacterial cell protection from a multitude of chemical, cellular and physical antagonists [143]. The bacteria encased in biofilms are able to tolerate significantly higher concentrations of antimicrobials and disinfectants than free-floating bacterial cells [39, 143,144]. Furthermore, the bacterial cells residing in biofilms are more resistant to phagocytosis and are protected from pH extremes and physical desiccation [143].…”

Section: The Formation Of Biofilmsmentioning

confidence: 99%

“…The bacteria encased in biofilms are able to tolerate significantly higher concentrations of antimicrobials and disinfectants than free-floating bacterial cells [39, 143,144]. Furthermore, the bacterial cells residing in biofilms are more resistant to phagocytosis and are protected from pH extremes and physical desiccation [143]. The protective effect of biofilms is in part attributable to the physiological changes that the bacterial cells undergo whilst growing en masse.…”

Section: The Formation Of Biofilmsmentioning

confidence: 99%

“…The protective effect of biofilms is in part attributable to the physiological changes that the bacterial cells undergo whilst growing en masse. Bacteria existing within biofilms grow more slowly than exponentialphase bacteria [143]. This is partly due to restricted diffusion of gases and nutrients within the biofilm environment, but this is also affected by alterations in bacterial gene expression [145].…”

Section: The Formation Of Biofilmsmentioning

confidence: 99%

“…In vitro methods for analyzing the antimicrobial susceptibility do not take into consideration the protective effect afforded by biofilm growth, which commonly occurs during the course of staphylococcal infections [143]. Due to the protective environment afforded by biofilm growth and the accompanying changes in bacterial physiology, bacterial cells growing in biofilms are typically able to tolerate antimicrobial concentrations 10-fold to 1000-fold higher than planktonic bacterial populations [143]. A few methods have evolved to investigate the antimicrobial susceptibility of isolates growing in biofilms, with the commercially available method from Innovotech Inc. (Edmonton, Canada) gaining wide acceptance.…”

Section: Evaluating the Antimicrobial Susceptibility Of Staphylococcamentioning

confidence: 99%

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Antimicrobial Resistance in Staphylococci at the Human– Animal Interface

Schmidt¹,

Kock²,

Ehlers³

2015

Antimicrobial Resistance - An Open Challenge

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The widespread and often indiscriminate use of antimicrobials in animals is considered an important driving force behind the emergence and spread of antimicrobial-resistant bacteria. The emergence of livestock-associated methicillin-resistant Staphylococcus aureus and the description of a novel methicillin-resistant gene, mecC, have renewed concerns regarding the role of animals as reservoirs and a source for the evolution of novel, virulent zoonotic pathogens. The transfer of antimicrobial-resistant bacteria residing in, or on, animals to close human contacts or the introduction of the bacteria into the food supply chain is a cause for concern. The purpose of this mini-review is to provide a background to the genus Staphylococcus and the emergence of antimicrobial resistance as well as a discussion on the most significant antimicrobial resistance mechanisms. The use of antimicrobials in animal husbandry is discussed and the interface between humans and different animal populations is closely examined. Finally, the need for antimicrobial monitoring programmes is discussed and is supplemented with information pertaining to antimicrobial susceptibility testing and molecular typing of staphylococcal isolates.

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Section: Alternate Bacterial Strategies To Circumvent the Action Of Amentioning

confidence: 99%

Section: The Formation Of Biofilmsmentioning

confidence: 99%

Section: The Formation Of Biofilmsmentioning

confidence: 99%

Section: The Formation Of Biofilmsmentioning

confidence: 99%

Section: Evaluating the Antimicrobial Susceptibility Of Staphylococcamentioning

confidence: 99%

See 3 more Smart Citations

Antimicrobial Resistance in Staphylococci at the Human– Animal Interface

Schmidt¹,

Kock²,

Ehlers³

2015

Antimicrobial Resistance - An Open Challenge

View full text Add to dashboard Cite

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Deacetylation of Fungal Exopolysaccharide Mediates Adhesion and Biofilm Formation

Lee

Geller

Bamford

et al. 2016

mBio

200

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The mold Aspergillus fumigatus causes invasive infection in immunocompromised patients. Recently, galactosaminogalactan (GAG), an exopolysaccharide composed of galactose and N-acetylgalactosamine (GalNAc), was identified as a virulence factor required for biofilm formation. The molecular mechanisms underlying GAG biosynthesis and GAG-mediated biofilm formation were unknown. We identified a cluster of five coregulated genes that were dysregulated in GAG-deficient mutants and whose gene products share functional similarity with proteins that mediate the synthesis of the bacterial biofilm exopolysaccharide poly-(β1-6)-N-acetyl-d-glucosamine (PNAG). Bioinformatic analyses suggested that the GAG cluster gene agd3 encodes a protein containing a deacetylase domain. Because deacetylation of N-acetylglucosamine residues is critical for the function of PNAG, we investigated the role of GAG deacetylation in fungal biofilm formation. Agd3 was found to mediate deacetylation of GalNAc residues within GAG and render the polysaccharide polycationic. As with PNAG, deacetylation is required for the adherence of GAG to hyphae and for biofilm formation. Growth of the Δagd3 mutant in the presence of culture supernatants of the GAG-deficient Δuge3 mutant rescued the biofilm defect of the Δagd3 mutant and restored the adhesive properties of GAG, suggesting that deacetylation is an extracellular process. The GAG biosynthetic gene cluster is present in the genomes of members of the Pezizomycotina subphylum of the Ascomycota including a number of plant-pathogenic fungi and a single basidiomycete species, Trichosporon asahii, likely a result of recent horizontal gene transfer. The current study demonstrates that the production of cationic, deacetylated exopolysaccharides is a strategy used by both fungi and bacteria for biofilm formation.

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Intraphagolysosomal conditions predispose to Staphylococcus epidermidis small colony variants persistence in macrophages

et al. 2018

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Staphylococcus epidermidis small colony variants can survive inside macrophages and their survival has been proposed as a pivotal process in the pathogenesis of biomaterial associated infections. In the present study the intracellular location of clinical isolates of SCV and parental wild type strains inside macrophages was determined. Furthermore, the effect of IFN-γ and rapamycin on the level of SCV/WT as well as lysosomes colocalisation and iNOS induction in THP-activated macrophages in response to WT and SCV strains of Staphylococcus epidermidis were examined. It was demonstrated that SCV strain of S. epidermidis can survive and persist inside macrophages and its intracellular survival is supported by the induction of phagosomal acidification. The ability to reduce the high proportion of LysoTracker positive SCV containing phagosomes was exclusively found when IFN-γ was used. The findings suggest that IFN-γ mediates SCV killing via two distinct mechanisms, phagosome alkalisation and an increased iNOS synthesis, so the cytokine may control S. epidermidis WT and SCV infection in macrophages. Staphylococcus epidermidis SCV is a less potent stimulus of iNOS than the WT strain and the feature may help SCV to persist in hostile environment of macrophages. Rapamycin treatment did not influence the iNOS synthesis but reduced the percentage of both bacterial strains within acidic organelles. However, the percentage of SCV within LysoTracker positive organelles, even though reduced comparing to non-primed cells, was higher than in the WT strain indicating that Staphylococcus epidermidis possesses unique metabolic features allowing SCV to survive within macrophages.

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Adaptation to Stress: Biofilms and Small‐Colony Variants

Cited by 6 publications

References 155 publications

Antimicrobial Resistance in Staphylococci at the Human– Animal Interface

Antimicrobial Resistance in Staphylococci at the Human– Animal Interface

Deacetylation of Fungal Exopolysaccharide Mediates Adhesion and Biofilm Formation

Intraphagolysosomal conditions predispose to Staphylococcus epidermidis small colony variants persistence in macrophages

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