SMALL COLONY VARIANTS OF<i>ESCHERICHIA COLI</i>

Hirsch, Herbert M.

doi:10.1128/jb.81.3.448-458.1961

Cited by 10 publications

(4 citation statements)

References 22 publications

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“…There are various reports on the effect of environmental factors such as oxygen level, pH, temperature, osmolarity used on biofilm formation among different bacterial species such as Stenotrophomonas maltophilia [9] , Pseudomonas aeruginosa [7] and Hafnia alvei strains [10] . Another interesting feature is the differentiation of bacteria into large and small colony variants which occur due to environmental stress (increase in metal ion or antibiotic concentration), or in cultures stored over long periods of time [11] . They are also characterised by decreased susceptibility to antibiotic treatment, reduced carbohydrate metabolism, altered virulence factor expression, elevated biofilm formation capacity [12] , [13] and their prolonged in vitro persistence [14] .…”

Section: Introductionmentioning

confidence: 99%

The Effect of Environmental Conditions on Biofilm Formation of Burkholderia pseudomallei Clinical Isolates

et al. 2012

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Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs) and small colony variants (SCVs) morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30°C, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37°C. In addition, octanoyl-homoserine lactone (C8-HSL), a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C10-HSL) and dodecanoyl-homoserine lactone (C12-HSL) were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation.

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Section: Introductionmentioning

confidence: 99%

The Effect of Environmental Conditions on Biofilm Formation of Burkholderia pseudomallei Clinical Isolates

et al. 2012

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“…We have yet to determine the genetic and molecular basis of the observed SCVs, but they appear to be distinct from the previously described mechanisms [33][34][35][36][37] . Certain mutations observed here (Supplemental Table 1) might account for changes in MICs in the SCVs.…”

Section: Discussionmentioning

confidence: 78%

“…SCVs have been implicated in treatment failure, primarily in Staphylococcus aureus, but there are limited reports of SCVs being associated with treatment failure in E. coli 27,28 . We have yet to determine the genetic and molecular basis of the observed SCVs, but they appear to be distinct from the previously described mechanisms [29][30][31][32][33] . Certain mutations observed here (Supplemental Table 1) might account for the SCV phenotype.…”

Section: Discussionmentioning

confidence: 78%

The Evolution of Heteroresistance via Small Colony Variants in Escherichia coli Following Long Term Exposure to Bacteriostatic Antibiotics

Gil-Gil,

Berryhill,

Manuel

et al. 2023

Preprint

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Traditionally, bacteriostatic antibiotics are agents able to arrest bacterial growth. Despite being unable to kill bacterial cells, when they are used clinically the outcome of these drugs is frequently as effective as when a bactericidal drug is used. We explore the dynamics ofEscherichia coliafter exposure to two ribosome-targeting bacteriostatic antibiotics, chloramphenicol and azithromycin, for thirty days. The results of our experiments provide evidence that bacteria exposed to these drugs replicate, evolve, and generate a sub-population of small colony variants (SCVs) which are resistant to multiple drugs. These SCVs contribute to the evolution of heteroresistance and rapidly revert to a susceptible state once the antibiotic is removed. Stated another way, exposure to bacteriostatic drugs selects for the evolution of heteroresistance in populations previously lacking this trait. More generally, our results question the definition of bacteriostasis as populations exposed to bacteriostatic drugs are replicating despite the lack of net growth.

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“…As such, copper would be the first divalent cation of measurable abundance to be sequestered in seawater. Copper toxicity for E. coli can be readily reduced by chelating agents (Saklawska-Szymonowa 1953;Hirsch 1961;Hofsten 1962 ) .…”

Section: Discussionmentioning

confidence: 99%

GROWTH OF ESCHERICHIA COLI IN HEAT‐ AND COPPER‐TREATED SYNTHETIC SEAWATER1

Jones

1967

Limnology & Oceanography

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SMALL COLONY VARIANTS OFESCHERICHIA COLI

Cited by 10 publications

References 22 publications

The Effect of Environmental Conditions on Biofilm Formation of Burkholderia pseudomallei Clinical Isolates

The Effect of Environmental Conditions on Biofilm Formation of Burkholderia pseudomallei Clinical Isolates

The Evolution of Heteroresistance via Small Colony Variants in Escherichia coli Following Long Term Exposure to Bacteriostatic Antibiotics

GROWTH OF ESCHERICHIA COLI IN HEAT‐ AND COPPER‐TREATED SYNTHETIC SEAWATER1

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