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Untersuchungen zum Wachstum und zur Persistenz von Escherichia coli O26:H11, O157:H7, O157:H45 und O159:H- bei Säurestress


Zweifel, C; Nauer, T; Stephan, R (2009). Untersuchungen zum Wachstum und zur Persistenz von Escherichia coli O26:H11, O157:H7, O157:H45 und O159:H- bei Säurestress. Archiv für Lebensmittelhygiene, 60(7-8):135-140.

Abstract

Shiga toxin-producing E. coli (STEC) are a major cause of foodborne diseases in humans. STEC infections have also been associated with acidified or fermented products. This fact may indicate an increased acid resistance of STEC. In the present study, four pathogenic E. coli strains (STEC O157:H7, STEC O26:H11, STEC O159:H-, EPEC O157:H45) and a control strain (E. coli K12) were examined for growth and persistence under hydrochloric, acetic and lactic acid stress. In the growth experiments, the O157:H45 strain (hydrochloric and acetic acid) and the O157:H7 strain (acetic acid) showed improved acid resistance, whereas no differences were evident for the other strains. In the survival experiments, significant differences were found between strains in the stationary and logarithmic growth phase. By comparison of the three acids, acetic acid proved to be most effective for growth inhibition and inactivation. The comparison of acid adapted and non adapted STEC O157:H7, STEC O159:H- and E. coli K12 showed that strains adapted with hydrochloric acid exhibited improved acid resistance, but this effect was not confirmed after lactic acid adaptation. The adaptation with acetic acid improved the acid resistance of STEC O159:H- and E. coli K12, whereas that of STEC O157:H7 was not affected. Consequently, remarkable strain-to-strain variation in the acid stress response of "enteropathogenic" E. coli was evident. This variation was rather influenced by the acid applied than by the serotype or the pattern of virulence factors of the strains.

Abstract

Shiga toxin-producing E. coli (STEC) are a major cause of foodborne diseases in humans. STEC infections have also been associated with acidified or fermented products. This fact may indicate an increased acid resistance of STEC. In the present study, four pathogenic E. coli strains (STEC O157:H7, STEC O26:H11, STEC O159:H-, EPEC O157:H45) and a control strain (E. coli K12) were examined for growth and persistence under hydrochloric, acetic and lactic acid stress. In the growth experiments, the O157:H45 strain (hydrochloric and acetic acid) and the O157:H7 strain (acetic acid) showed improved acid resistance, whereas no differences were evident for the other strains. In the survival experiments, significant differences were found between strains in the stationary and logarithmic growth phase. By comparison of the three acids, acetic acid proved to be most effective for growth inhibition and inactivation. The comparison of acid adapted and non adapted STEC O157:H7, STEC O159:H- and E. coli K12 showed that strains adapted with hydrochloric acid exhibited improved acid resistance, but this effect was not confirmed after lactic acid adaptation. The adaptation with acetic acid improved the acid resistance of STEC O159:H- and E. coli K12, whereas that of STEC O157:H7 was not affected. Consequently, remarkable strain-to-strain variation in the acid stress response of "enteropathogenic" E. coli was evident. This variation was rather influenced by the acid applied than by the serotype or the pattern of virulence factors of the strains.

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Other titles:Growth and persistence of Escherichia coli O26:H11, O157:H7, O157:H45 and O159:H- related to acid stress
Item Type:Journal Article, refereed, original work
Communities & Collections:05 Vetsuisse Faculty > Institute of Food Safety and Hygiene
Dewey Decimal Classification:570 Life sciences; biology
610 Medicine & health
Language:German
Date:2009
Deposited On:15 Jan 2010 16:23
Last Modified:05 Apr 2016 13:38
Publisher:M.& H. Schaper
ISSN:0003-925X
Publisher DOI:https://doi.org/10.2376/0003-925X-60-135

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