Association of Prophage Antiterminator Q Alleles and Susceptibility to Food-Processing Treatments Applied to Escherichia coli O157 in Laboratory Media

Malone, Aaron S.; Yousef, Ahmed E.; LeJeune, Jeffrey T.

doi:10.4315/0362-028x-70.11.2617

Cited by 5 publications

(5 citation statements)

References 17 publications

(16 reference statements)

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“…Further studies are required to draw any conclusion regarding the acid resistance in STEC O157. In other studies on stress resistance of STEC O157, the results of Benito et al (2) are concordant with our results, while the results of Malone et al (22) are not. In order to compare the results across studies, additional work is needed to confirm the genotypes under investigation.…”

Section: Figsupporting

confidence: 91%

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Lee

French

Jones

et al. 2012

Appl Environ Microbiol

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ABSTRACTTo evaluate the relationship between bacterial genotypes and stress resistance patterns, we exposed 57 strains of Shiga toxin-producingEscherichia coli(STEC) O157 to acid, freeze-thaw, heat, osmotic, oxidative, and starvation stresses. Inactivation rates were calculated in each assay and subjected to univariate and multivariate analyses, including principal component analysis (PCA) and cluster analysis. Thestxgenotype was determined for each strain as was the lineage-specific polymorphism assay (LSPA6) genotype. In univariate analyses, strains of thestx1stx2genotype showed greater resistance to heat than strains of thestx1stx2cgenotype; moreover, strains of thestx1stx2genotype showed greater resistance to starvation than strains of thestx2orstx2cgenotypes. LSPA6 lineage I (LI) strains showed greater resistance to heat and starvation than LSPA6 lineage II (LII) strains. PCA revealed a general trend that a strain with greater resistance to one type of stress tended to have greater resistance to other types of stresses. In cluster analysis, STEC O157 strains were grouped into stress-resistant, stress-sensitive, and intermediate clusters. Instxgenotypes, all strains of thestx1stx2genotype were grouped with the stress-resistant cluster, whereas 72.7% (8/11) of strains of thestx1stx2cgenotype grouped with the stress-sensitive cluster. In LI strains, 77.8% (14/18) of the strains were grouped with the stress-resistant cluster, whereas 64.7% (11/17) of LII strains were grouped with the stress-sensitive cluster. These results indicate that the genotypes of STEC O157 that are frequently associated with human illness, i.e., LI or thestx1stx2genotype, have greater multiple stress resistance than do strains of other genotypes.

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Section: Figsupporting

confidence: 91%

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Lee

French

Jones

et al. 2012

Appl Environ Microbiol

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“…However, the ability to withstand antimicrobial interventions did not differ between strains of EC O157:H7 with genetic polymorphism associated with human disease and strains not found in humans (Arthur et al, 2008). The prophage-encoded antiterminator Q gene upstream of stx2 was associated with resistance of EC O157 to inactivation by high pressure, heat, and UV and gamma radiation (Malone et al, 2007), and EC O157:H7 repaired UV-induced damage within 30 min versus 2 h required by nonpathogenic E. coli (Zimmer- Thomas et al, 2007).…”

Section: Ferens and Hovdementioning

confidence: 91%

Escherichia coliO157:H7: Animal Reservoir and Sources of Human Infection

Ferens

Hovde

2011

Foodborne Pathogens and Disease

478

327

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This review surveys the literature on carriage and transmission of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the context of virulence factors and sampling=culture technique. EHEC of the O157:H7 serotype are worldwide zoonotic pathogens responsible for the majority of severe cases of human EHEC disease. EHEC O157:H7 strains are carried primarily by healthy cattle and other ruminants, but most of the bovine strains are not transmitted to people, and do not exhibit virulence factors associated with human disease. Prevalence of EHEC O157:H7 is probably underestimated. Carriage of EHEC O157:H7 by individual animals is typically shortlived, but pen and farm prevalence of specific isolates may extend for months or years and some carriers, designated as supershedders, may harbor high intestinal numbers of the pathogen for extended periods. The prevalence of EHEC O157:H7 in cattle peaks in the summer and is higher in postweaned calves and heifers than in younger and older animals. Virulent strains of EHEC O157:H7 are rarely harbored by pigs or chickens, but are found in turkeys. The bacteria rarely occur in wildlife with the exception of deer and are only sporadically carried by domestic animals and synanthropic rodents and birds. EHEC O157:H7 occur in amphibian, fish, and invertebrate carriers, and can colonize plant surfaces and tissues via attachment mechanisms different from those mediating intestinal attachment. Strains of EHEC O157:H7 exhibit high genetic variability but typically a small number of genetic types predominate in groups of cattle and a farm environment. Transmission to people occurs primarily via ingestion of inadequately processed contaminated food or water and less frequently through contact with manure, animals, or infected people.

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“…Several research groups have dedicated efforts in the last decade to evaluate the heterogeneity in STEC stress resistance, using both laboratory domesticated strains and field isolates ( Saridakis et al, 2004 ; Bhagwat et al, 2006 ; Malone et al, 2007 ; Vanaja et al, 2009 ; Lee et al, 2012 ; Alvarez-Ordóñez et al, 2013 ; Elhadidy and Mohammed, 2013 ). Information available in the literature so far suggests that the ability to survive in stressful conditions varies substantially among isolates within a given genotype, whereas there is controversy on the fact of whether some genotypes are better equipped to face the challenge of a changing environment.…”

Section: Discussionmentioning

confidence: 99%

“…Information available in the literature so far suggests that the ability to survive in stressful conditions varies substantially among isolates within a given genotype, whereas there is controversy on the fact of whether some genotypes are better equipped to face the challenge of a changing environment. In a study that was undertaken to compare resistance to different processing treatments (high-pressure processing, heat, ultraviolet, and gamma radiation) among different E. coli O157:H7 isolates encoding different antiterminator Q gene alleles present upstream of the Shiga toxin gene, Malone et al (2007) showed that isolates encoding the Q 933 allele were more sensitive to all processing treatments than were isolates encoding the Q 21 allele. Moreover, the stx -negative isolates were more resistant to UV and gamma radiation (but not to heat or pressure) than were isolates encoding either the Q 933 or Q 21 allelles.…”

Section: Discussionmentioning

confidence: 99%

Diversity of Survival Patterns among Escherichia coli O157:H7 Genotypes Subjected to Food-Related Stress Conditions

Elhadidy

Álvarez‐Ordóñez

2016

Front. Microbiol.

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The purpose of this study was to evaluate the resistance patterns to food-related stresses of Shiga toxin producing Escherichia coli O157:H7 strains belonging to specific genotypes. A total of 33 E. coli O157:H7 strains were exposed to seven different stress conditions acting as potential selective pressures affecting the transmission of E. coli O157:H7 to humans through the food chain. These stress conditions included cold, oxidative, osmotic, acid, heat, freeze-thaw, and starvation stresses. The genotypes used for comparison included lineage-specific polymorphism, Shiga-toxin-encoding bacteriophage insertion sites, clade type, tir (A255T) polymorphism, Shiga toxin 2 subtype, and antiterminator Q gene allele. Bacterial resistance to different stressors was calculated by determining D-values (times required for inactivation of 90% of the bacterial population), which were then subjected to univariate and multivariate analyses. In addition, a relative stress resistance value, integrating resistance values to all tested stressors, was calculated for each bacterial strain and allowed for a ranking-type classification of E. coli O157:H7 strains according to their environmental robustness. Lineage I/II strains were found to be significantly more resistant to acid, cold, and starvation stress than lineage II strains. Similarly, tir (255T) and clade 8 encoding strains were significantly more resistant to acid, heat, cold, and starvation stress than tir (255A) and non-clade 8 strains. Principal component analysis, which allows grouping of strains with similar stress survival characteristics, separated strains of lineage I and I/II from strains of lineage II, which in general showed reduced survival abilities. Results obtained suggest that lineage I/II, tir (255T), and clade 8 strains, which have been previously reported to be more frequently associated with human disease cases, have greater multiple stress resistance than strains of other genotypes. The results from this study provide a better insight into how selective pressures encountered through the food chain may play a role in the epidemiology of STEC O157:H7 through controlling the transmission of highly adapted strains to humans.

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Association of Prophage Antiterminator Q Alleles and Susceptibility to Food-Processing Treatments Applied to Escherichia coli O157 in Laboratory Media

Cited by 5 publications

References 17 publications

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Escherichia coliO157:H7: Animal Reservoir and Sources of Human Infection

Diversity of Survival Patterns among Escherichia coli O157:H7 Genotypes Subjected to Food-Related Stress Conditions

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