Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane

Hanna-Leena Alakomi, Eija Skyttä, Maria Saarela, Tiina Mattila-Sandholm, Kyösti Latva-Kala, Ilkka Helander (Corresponding Author)

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Abstract

The effect of lactic acid on the outer membrane permeability ofEscherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl2. Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosawas effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.
Original languageEnglish
Pages (from-to)2001 - 2005
Number of pages5
JournalApplied and Environmental Microbiology
Volume66
Issue number5
DOIs
Publication statusPublished - 2000
MoE publication typeA1 Journal article-refereed

Fingerprint

Gram-Negative Bacteria
Gram-negative bacteria
lactic acid
lactic acid bacteria
Lactic Acid
membrane
bacterium
Membranes
acid
Pseudomonas aeruginosa
Edetic Acid
EDTA
Hydrochloric Acid
hydrochloric acid
sodium dodecyl sulfate
anti-infective properties
Sodium Dodecyl Sulfate
assay
lipopolysaccharides
Lipopolysaccharides

Cite this

Alakomi, Hanna-Leena ; Skyttä, Eija ; Saarela, Maria ; Mattila-Sandholm, Tiina ; Latva-Kala, Kyösti ; Helander, Ilkka. / Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane. In: Applied and Environmental Microbiology. 2000 ; Vol. 66, No. 5. pp. 2001 - 2005.
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abstract = "The effect of lactic acid on the outer membrane permeability ofEscherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl2. Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosawas effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.",
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Alakomi, H-L, Skyttä, E, Saarela, M, Mattila-Sandholm, T, Latva-Kala, K & Helander, I 2000, 'Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane', Applied and Environmental Microbiology, vol. 66, no. 5, pp. 2001 - 2005. https://doi.org/10.1128/AEM.66.5.2001-2005.2000

Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane. / Alakomi, Hanna-Leena; Skyttä, Eija; Saarela, Maria; Mattila-Sandholm, Tiina; Latva-Kala, Kyösti; Helander, Ilkka (Corresponding Author).

In: Applied and Environmental Microbiology, Vol. 66, No. 5, 2000, p. 2001 - 2005.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane

AU - Alakomi, Hanna-Leena

AU - Skyttä, Eija

AU - Saarela, Maria

AU - Mattila-Sandholm, Tiina

AU - Latva-Kala, Kyösti

AU - Helander, Ilkka

PY - 2000

Y1 - 2000

N2 - The effect of lactic acid on the outer membrane permeability ofEscherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl2. Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosawas effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.

AB - The effect of lactic acid on the outer membrane permeability ofEscherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl2. Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosawas effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.

U2 - 10.1128/AEM.66.5.2001-2005.2000

DO - 10.1128/AEM.66.5.2001-2005.2000

M3 - Article

VL - 66

SP - 2001

EP - 2005

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

SN - 0099-2240

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