Shiga‐Toxin Genes and Genetic Diversity of <i>Escherichia coli</i> Isolated from Pasteurized Cow Milk in Brazil

Hoffmann, S; Pieretti, Gabriella Giani; Fiorini, Adriana; Patussi, Eliana Valéria; Cardoso, Rosilene Fressatti; Mikcha, Jane Martha Graton

doi:10.1111/1750-3841.12477

Cited by 9 publications

(11 citation statements)

References 26 publications

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“…These findings strongly suggest that these strains are the ones predominantly circulating in Danish farms and might be the archetypal commensal E. coli in the gut of pigs. Even though some isolates were predominant, and a limited number of profiles were found at the single animal level, we observed a high genetic diversity among E. coli strains isolated from different pigs regardless of whether they shared the same pen or not as previously demonstrated in other hosts [16, 26–28]. We also showed that apparently the majority of profiles were represented by strains that are resistant to either ampicillin or tetracycline or both.…”

Section: Discussionsupporting

confidence: 76%

“…While this limited number of different strains was observed at the animal level, REP-PCR DNA fingerprint analysis revealed extensive genetic diversity among E. coli strains isolated from different pigs regardless of whether they shared the same pen or not. The high genetic diversity displayed by E. coli was also demonstrated in humans and other animals such as cows, coyotes, sheep and goats in previous studies [16, 26–28]. …”

Section: Discussionmentioning

confidence: 56%

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Genotype variation and genetic relationship among Escherichia coli from nursery pigs located in different pens in the same farm

Herrero-Fresno¹,

Ahmed²,

Hansen³

et al. 2017

BMC Microbiol

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BackgroundSo far, little is known about the genetic diversity and relatedness among Escherichia coli (E. coli) populations in the gut of swine. Information on this is required to improve modeling studies on antimicrobial resistance aiming to fight its occurrence and development. This work evaluated the genotype variation of E. coli isolated from swine fecal samples at the single pig and pen level, as well as between pens using repetitive extragenic palindromic (REP) PCR fingerprinting and pulsed field gel electrophoresis (PFGE). The genetic diversity of strains collected from media supplemented with ampicillin or tetracycline was also investigated. Besides, the genetic relationship of strains within each pen, between pens, as well as among strains within each group isolated from media with or without antibiotic, was assessed.ResultsREP-PCR patterns (N = 75) were generated for all the isolates (N = 720). Two profiles (REP_2 and REP_5) dominated, accounting for 23.7 and 23.3% of all isolates, respectively. At the pig and at the pen level, the number of different strains ranged from two to eight, and from 27 to 31, respectively, and multiple isolates from a single pen were found to be identical; however, in some of the pens, additional strains occurred at a lower frequency. E. coli isolates yielding different REP profiles were subjected to PFGE and led to 41 different genotypes which were also compared.ConclusionsDespite the presence of dominant strains, our results suggest a high genetic diversity of E. coli strains exist at the pen level and between pens. Selection with antibiotic seems to not affect the genetic diversity. The dominant REP profiles were the same found in a previous study in Denmark, which highlights that the same predominant strains are circulating in pigs of this country and might represent the archetypal E.coli commensal in pigs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0912-3) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 76%

Section: Discussionmentioning

confidence: 56%

Genotype variation and genetic relationship among Escherichia coli from nursery pigs located in different pens in the same farm

Herrero-Fresno¹,

Ahmed²,

Hansen³

et al. 2017

BMC Microbiol

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“…The absence of non-D157 STEC isolates from cheeses collected in the others periods was a good indication of the involvement of the abovementioned food worker with the contamination process. Hoffmann et al (2014) analyzed 87 E. coli strains isolated from pasteurized milk obtained from 22 farm dairies located at Parana state in Brazil and did not detect the stx1, stx2, and eae virulence genes among the E. coli isolates. Dkura & Marin (2014) examined 330 E. coli strains isolated from 111 Minas frescal cheeses from Southwest Minas Gerais State and also did not detect stx 1, stx 2, or eae genes among the E. coli isolates.…”

Section: Resultsmentioning

confidence: 99%

Occurrence of non-O157 Shiga toxin-encoding Escherichia coli in artisanal mozzarella cheese in Brazil: risk factor associated with food workers

Cardoso

Marin

2016

Food Sci. Technol

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Mozzarella cheese is considered a safe food due to the high temperature treatment used in the traditional process of stretching into hot water; however, a post-process contamination during the cheese manufacture or during the processing (before distribution) could occur. This study investigated the occurrence of Shiga toxin-encoding Escherichia coli (STEC) strains in homemade-mozzarella cheese. In total, 59 raw milk cheese samples collected at a local producer in the Jequitinhonha Valley (Northeast of Minas Gerais, Brazil) were submitted for microbiological analysis, and 38 (64.4%) tested positive for E. coli. Then, 147 strains of E. coli were isolated from positive samples and screened by polymerase chain reaction for the presence of the genes encoding the following virulence factors: stx1 and stx 2 (verotoxin types 1 and 2) and eae (intimin). All the isolates were negative for the stx 2, 14 isolates (9.5%) were positive for the stx1 gene, and 11 of them also harbored the eae gene. A food worker was probably involved in cheese contamination during the manufacture schedule. While the development of STEC infection in humans is not completely understood, all STEC-contaminated food can be considered potentially hazardous.Keywords: Escherichia coli; virulence genes; homemade cheese; food handler contamination.Practical Application: This study demonstrates that mozzarella cheese may be a vehicle for STEC non-D157 strain dissemination among humans, which is a reason for concern due to the high consumption of this cheese by the Brazilian population.

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“…Wide ranges of genetic diversity were also demonstrated by others in studies on diversity of commensal E . coli from humans and from other animals [15,27–29]. …”

Section: Discussionmentioning

confidence: 99%

The genetic diversity of commensal Escherichia coli strains isolated from non-antimicrobial treated pigs varies according to age group

2017

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This is the first report on the genetic diversity of commensal E. coli from pigs reared in an antibiotic free production system and belonging to different age groups. The study investigated the genetic diversity and relationship of 900 randomly collected commensal E. coli strains from non-antimicrobial treated pigs assigned to five different age groups in a Danish farm. Fifty-two unique REP profiles were detected suggesting a high degree of diversity. The number of strains per pig ranged from two to 13. The highest and the lowest degree of diversity were found in the early weaners group (Shannon diversity index, H' of 2.22) and piglets (H' of 1.46) respectively. The REP profiles, R1, R7 and R28, were the most frequently observed in all age groups. E. coli strains representing each REP profile and additional strains associated with the dominant profiles were subjected to PFGE and were assigned to 67 different genotypes. Whole genome sequence analysis of 52 isolates leading to unique REP profiles identified a high level of sequence variation. Six and six strains were assigned to sequence type ST10 and sequence type ST58, respectively. Virulence and antimicrobial resistance genes, as well as, genes associated with mobile genetic elements were commonly found among these commensal E. coli strains. Interestingly, strains yielding the three most common REP profiles clustered together in the SNPs phylogenetic tree, and such strains may represent the archetypal commensal E. coli in Danish pigs.

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Shiga‐Toxin Genes and Genetic Diversity of Escherichia coli Isolated from Pasteurized Cow Milk in Brazil

Abstract: Knowledge about the presence of diarrheagenic Escherichia coli in pasteurized milk is important developing and implementing control measures in milk and dairy production.

Cited by 9 publications

References 26 publications

Genotype variation and genetic relationship among Escherichia coli from nursery pigs located in different pens in the same farm

Genotype variation and genetic relationship among Escherichia coli from nursery pigs located in different pens in the same farm

Occurrence of non-O157 Shiga toxin-encoding Escherichia coli in artisanal mozzarella cheese in Brazil: risk factor associated with food workers

The genetic diversity of commensal Escherichia coli strains isolated from non-antimicrobial treated pigs varies according to age group

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