Isolation and identification of bacterial pathogens in minimally processed vegetable salads in some Saudi restaurants using DNA sequencing

Mohammad A. Khiyami, Maher M. Shehata, Noura A. Al-Faris

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

Abstract

The genetic diversity and relationship amongst the bacterial populations were determined in fresh salad samples (Tabbouleh, Fattoush, Hummus, Mutabbel and Caesar) collected from various restaurants located in five different areas (west, north, south, east and center) in Riyadh (the capital city of Saudi Arabia). Isolated colonies found were identified via molecular methods. Total number of identified isolates in the vegetable salads Tabbouleh, Fattoush, Mutabbel, Hummus and Caesar were 24, 20, 18, 16 and 12, respectively. Pseudomonas sp., Bacillus cereus and Enterobacter aerogenes were recorded in the five types of vegetable salads. Escherichia coli, Klebsiella sp., Kluyvera cryocrescens and Kluyvera ascorbata were recorded in all types of vegetable salads except Caesar. Vegetable salads collected from all sites were contaminated with E. coli, Enterobacter sp. and Enterobacter aerogenes. Elevated level of contamination with E. coli was recorded in the samples collected from the north and east areas, while high level of contamination with Enterobacter aerogenes was recorded in the samples collected from central area. Estimation of bacterial genetic relationships was determined using DNA sequencing, phylogenetic tree and bioinformatic techniques. The 36 isolates were arranged in one main cluster including 34 bacterial species and two bacterial species Pseudomonas and Bacillus cereus were out groups with similarity index range of 0.008- 0.063 and 0.008-0.125, respectively, to the main group. This cluster was subdivided into two subgroups: subgroup A included Acinetobacter sp. and Stenotrophomonas sp.; subgroup B included 32 bacterial species. Subgroup B contains one major subgroup C comprising 31 bacterial species with similarity index range of 0.061-0.019 to Hafnia alvei. Subgroup C was subdivided into subgroup D including 15 bacterial species and subgroup E including 16 bacterial species. The inter-specific analysis of the sequences showed that most bacterial species exhibit a homogeneous sequence indicating a low level of polymorphism, which is congruent with the reduced variability found in these bacterial species from other salad sources. The identification of intra-specific variation suggests that DNA sequencing had a potential to aid in quick identification and classification of bacterial isolates in salads. The reproducibility generated by this technique may lead to the development of specific molecular markers for characterization of these microbes.

Original languageEnglish
Pages (from-to)94-100
Number of pages7
JournalJournal of Food, Agriculture and Environment
Volume9
Issue number3-4
Publication statusPublished - 1 Jan 2011

Fingerprint

Restaurants
salads
restaurants
Enterobacter aerogenes
DNA Sequence Analysis
Vegetables
vegetable
Kluyvera
sequence analysis
pathogen
vegetables
DNA
Bacillus cereus
pathogens
Escherichia coli
Pseudomonas
Hafnia alvei
Stenotrophomonas
Enterobacter
Acinetobacter

Keywords

  • Bacteria
  • DNA sequencing
  • Molecular markers
  • Phylogenetic tree
  • Vegetable salads

Cite this

@article{9b3461f150c545c9a1711474335b6a25,
title = "Isolation and identification of bacterial pathogens in minimally processed vegetable salads in some Saudi restaurants using DNA sequencing",
abstract = "The genetic diversity and relationship amongst the bacterial populations were determined in fresh salad samples (Tabbouleh, Fattoush, Hummus, Mutabbel and Caesar) collected from various restaurants located in five different areas (west, north, south, east and center) in Riyadh (the capital city of Saudi Arabia). Isolated colonies found were identified via molecular methods. Total number of identified isolates in the vegetable salads Tabbouleh, Fattoush, Mutabbel, Hummus and Caesar were 24, 20, 18, 16 and 12, respectively. Pseudomonas sp., Bacillus cereus and Enterobacter aerogenes were recorded in the five types of vegetable salads. Escherichia coli, Klebsiella sp., Kluyvera cryocrescens and Kluyvera ascorbata were recorded in all types of vegetable salads except Caesar. Vegetable salads collected from all sites were contaminated with E. coli, Enterobacter sp. and Enterobacter aerogenes. Elevated level of contamination with E. coli was recorded in the samples collected from the north and east areas, while high level of contamination with Enterobacter aerogenes was recorded in the samples collected from central area. Estimation of bacterial genetic relationships was determined using DNA sequencing, phylogenetic tree and bioinformatic techniques. The 36 isolates were arranged in one main cluster including 34 bacterial species and two bacterial species Pseudomonas and Bacillus cereus were out groups with similarity index range of 0.008- 0.063 and 0.008-0.125, respectively, to the main group. This cluster was subdivided into two subgroups: subgroup A included Acinetobacter sp. and Stenotrophomonas sp.; subgroup B included 32 bacterial species. Subgroup B contains one major subgroup C comprising 31 bacterial species with similarity index range of 0.061-0.019 to Hafnia alvei. Subgroup C was subdivided into subgroup D including 15 bacterial species and subgroup E including 16 bacterial species. The inter-specific analysis of the sequences showed that most bacterial species exhibit a homogeneous sequence indicating a low level of polymorphism, which is congruent with the reduced variability found in these bacterial species from other salad sources. The identification of intra-specific variation suggests that DNA sequencing had a potential to aid in quick identification and classification of bacterial isolates in salads. The reproducibility generated by this technique may lead to the development of specific molecular markers for characterization of these microbes.",
keywords = "Bacteria, DNA sequencing, Molecular markers, Phylogenetic tree, Vegetable salads",
author = "Khiyami, {Mohammad A.} and Shehata, {Maher M.} and Al-Faris, {Noura A.}",
year = "2011",
month = "1",
day = "1",
language = "English",
volume = "9",
pages = "94--100",
journal = "Journal of Food, Agriculture and Environment",
issn = "1459-0255",
publisher = "World Food Ltd. and WFL Publishers",
number = "3-4",

}

Isolation and identification of bacterial pathogens in minimally processed vegetable salads in some Saudi restaurants using DNA sequencing. / Khiyami, Mohammad A.; Shehata, Maher M.; Al-Faris, Noura A.

In: Journal of Food, Agriculture and Environment, Vol. 9, No. 3-4, 01.01.2011, p. 94-100.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Isolation and identification of bacterial pathogens in minimally processed vegetable salads in some Saudi restaurants using DNA sequencing

AU - Khiyami, Mohammad A.

AU - Shehata, Maher M.

AU - Al-Faris, Noura A.

PY - 2011/1/1

Y1 - 2011/1/1

N2 - The genetic diversity and relationship amongst the bacterial populations were determined in fresh salad samples (Tabbouleh, Fattoush, Hummus, Mutabbel and Caesar) collected from various restaurants located in five different areas (west, north, south, east and center) in Riyadh (the capital city of Saudi Arabia). Isolated colonies found were identified via molecular methods. Total number of identified isolates in the vegetable salads Tabbouleh, Fattoush, Mutabbel, Hummus and Caesar were 24, 20, 18, 16 and 12, respectively. Pseudomonas sp., Bacillus cereus and Enterobacter aerogenes were recorded in the five types of vegetable salads. Escherichia coli, Klebsiella sp., Kluyvera cryocrescens and Kluyvera ascorbata were recorded in all types of vegetable salads except Caesar. Vegetable salads collected from all sites were contaminated with E. coli, Enterobacter sp. and Enterobacter aerogenes. Elevated level of contamination with E. coli was recorded in the samples collected from the north and east areas, while high level of contamination with Enterobacter aerogenes was recorded in the samples collected from central area. Estimation of bacterial genetic relationships was determined using DNA sequencing, phylogenetic tree and bioinformatic techniques. The 36 isolates were arranged in one main cluster including 34 bacterial species and two bacterial species Pseudomonas and Bacillus cereus were out groups with similarity index range of 0.008- 0.063 and 0.008-0.125, respectively, to the main group. This cluster was subdivided into two subgroups: subgroup A included Acinetobacter sp. and Stenotrophomonas sp.; subgroup B included 32 bacterial species. Subgroup B contains one major subgroup C comprising 31 bacterial species with similarity index range of 0.061-0.019 to Hafnia alvei. Subgroup C was subdivided into subgroup D including 15 bacterial species and subgroup E including 16 bacterial species. The inter-specific analysis of the sequences showed that most bacterial species exhibit a homogeneous sequence indicating a low level of polymorphism, which is congruent with the reduced variability found in these bacterial species from other salad sources. The identification of intra-specific variation suggests that DNA sequencing had a potential to aid in quick identification and classification of bacterial isolates in salads. The reproducibility generated by this technique may lead to the development of specific molecular markers for characterization of these microbes.

AB - The genetic diversity and relationship amongst the bacterial populations were determined in fresh salad samples (Tabbouleh, Fattoush, Hummus, Mutabbel and Caesar) collected from various restaurants located in five different areas (west, north, south, east and center) in Riyadh (the capital city of Saudi Arabia). Isolated colonies found were identified via molecular methods. Total number of identified isolates in the vegetable salads Tabbouleh, Fattoush, Mutabbel, Hummus and Caesar were 24, 20, 18, 16 and 12, respectively. Pseudomonas sp., Bacillus cereus and Enterobacter aerogenes were recorded in the five types of vegetable salads. Escherichia coli, Klebsiella sp., Kluyvera cryocrescens and Kluyvera ascorbata were recorded in all types of vegetable salads except Caesar. Vegetable salads collected from all sites were contaminated with E. coli, Enterobacter sp. and Enterobacter aerogenes. Elevated level of contamination with E. coli was recorded in the samples collected from the north and east areas, while high level of contamination with Enterobacter aerogenes was recorded in the samples collected from central area. Estimation of bacterial genetic relationships was determined using DNA sequencing, phylogenetic tree and bioinformatic techniques. The 36 isolates were arranged in one main cluster including 34 bacterial species and two bacterial species Pseudomonas and Bacillus cereus were out groups with similarity index range of 0.008- 0.063 and 0.008-0.125, respectively, to the main group. This cluster was subdivided into two subgroups: subgroup A included Acinetobacter sp. and Stenotrophomonas sp.; subgroup B included 32 bacterial species. Subgroup B contains one major subgroup C comprising 31 bacterial species with similarity index range of 0.061-0.019 to Hafnia alvei. Subgroup C was subdivided into subgroup D including 15 bacterial species and subgroup E including 16 bacterial species. The inter-specific analysis of the sequences showed that most bacterial species exhibit a homogeneous sequence indicating a low level of polymorphism, which is congruent with the reduced variability found in these bacterial species from other salad sources. The identification of intra-specific variation suggests that DNA sequencing had a potential to aid in quick identification and classification of bacterial isolates in salads. The reproducibility generated by this technique may lead to the development of specific molecular markers for characterization of these microbes.

KW - Bacteria

KW - DNA sequencing

KW - Molecular markers

KW - Phylogenetic tree

KW - Vegetable salads

UR - http://www.scopus.com/inward/record.url?scp=80655134673&partnerID=8YFLogxK

M3 - Article

VL - 9

SP - 94

EP - 100

JO - Journal of Food, Agriculture and Environment

JF - Journal of Food, Agriculture and Environment

SN - 1459-0255

IS - 3-4

ER -