Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance
Background and Aim: Raw milk is considered an essential source of nutrition during all stages of human life because it offers a valuable supply of protein and minerals. Importantly, milk is considered a good media for the growth and contamination of many pathogenic bacteria, especially food-borne pa...
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| Format: | Article |
| Language: | English |
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Veterinary World
2021-09-01
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| Series: | Veterinary World |
| Subjects: | |
| Online Access: | http://www.veterinaryworld.org/Vol.14/September-2021/16.pdf |
| _version_ | 1819123367747256320 |
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| author | Waleed Younis Sabry Hassan Hams M. A. Mohamed |
| author_facet | Waleed Younis Sabry Hassan Hams M. A. Mohamed |
| author_sort | Waleed Younis |
| collection | DOAJ |
| description | Background and Aim: Raw milk is considered an essential source of nutrition during all stages of human life because it offers a valuable supply of protein and minerals. Importantly, milk is considered a good media for the growth and contamination of many pathogenic bacteria, especially food-borne pathogens such as Escherichia coli. Thus, the objective of this study was to characterize E. coli and detect its virulence factors and antibiotic resistance from raw milk samples.
Materials and Methods: Raw milk samples (n=100) were collected from different localities in Qena, Egypt, and investigated for the presence of E. coli using different biochemical tests, IMViC tests, serotyping to detect somatic antigen type, and molecularly by polymerase chain reaction (PCR) tests. The presence of different virulence and antimicrobial genes (hly, eae, stx1, stx2, blaTEM, tetA(A), and tetB genes) in E. coli isolates was evaluated using PCR.
Results: The results demonstrated that 10 out of 100 milk samples were contaminated with E. coli. Depending on serology, the isolates were classified as O114 (one isolate), O27 (two isolates), O111 (one isolate), O125 (two isolates), and untypeable (five isolates) E. coli. The sequencing of partially amplified 16S rRNA of the untypeable isolates resulted in one isolate, which was initially misidentified as untypeable E. coli but later proved as Enterobacter hormaechei. Moreover, antibacterial susceptibility analysis revealed that nearly all isolates were resistant to more than 3 families of antibiotics, particularly to β-lactams, clindamycin, and rifampin. PCR results demonstrated that all E. coli isolates showed an accurate amplicon for the blaTEM and tetA(A) genes, four isolates harbored eae gene, other four harbored tetB gene, and only one isolate exhibited a positive stx2 gene.
Conclusion: Our study explored vital methods for identifying E. coli as a harmful pathogen of raw milk using 16S rRNA sequencing, phylogenetic analysis, and detection of virulence factors and antibiotic-resistant genes. |
| first_indexed | 2024-12-22T07:07:14Z |
| format | Article |
| id | doaj.art-9af5a0fc46694af092fecc09645aaa7f |
| institution | Directory Open Access Journal |
| issn | 0972-8988 2231-0916 |
| language | English |
| last_indexed | 2024-12-22T07:07:14Z |
| publishDate | 2021-09-01 |
| publisher | Veterinary World |
| record_format | Article |
| series | Veterinary World |
| spelling | doaj.art-9af5a0fc46694af092fecc09645aaa7f2022-12-21T18:34:38ZengVeterinary WorldVeterinary World0972-89882231-09162021-09-011492410241810.14202/vetworld.2021.2410-2418Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistanceWaleed Younis0https://orcid.org/0000-0001-5572-0142Sabry Hassan1https://orcid.org/0000-0002-5852-6780Hams M. A. Mohamed2https://orcid.org/0000-0002-0650-204XDepartment of Microbiology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt.Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.Department of Microbiology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt.Background and Aim: Raw milk is considered an essential source of nutrition during all stages of human life because it offers a valuable supply of protein and minerals. Importantly, milk is considered a good media for the growth and contamination of many pathogenic bacteria, especially food-borne pathogens such as Escherichia coli. Thus, the objective of this study was to characterize E. coli and detect its virulence factors and antibiotic resistance from raw milk samples. Materials and Methods: Raw milk samples (n=100) were collected from different localities in Qena, Egypt, and investigated for the presence of E. coli using different biochemical tests, IMViC tests, serotyping to detect somatic antigen type, and molecularly by polymerase chain reaction (PCR) tests. The presence of different virulence and antimicrobial genes (hly, eae, stx1, stx2, blaTEM, tetA(A), and tetB genes) in E. coli isolates was evaluated using PCR. Results: The results demonstrated that 10 out of 100 milk samples were contaminated with E. coli. Depending on serology, the isolates were classified as O114 (one isolate), O27 (two isolates), O111 (one isolate), O125 (two isolates), and untypeable (five isolates) E. coli. The sequencing of partially amplified 16S rRNA of the untypeable isolates resulted in one isolate, which was initially misidentified as untypeable E. coli but later proved as Enterobacter hormaechei. Moreover, antibacterial susceptibility analysis revealed that nearly all isolates were resistant to more than 3 families of antibiotics, particularly to β-lactams, clindamycin, and rifampin. PCR results demonstrated that all E. coli isolates showed an accurate amplicon for the blaTEM and tetA(A) genes, four isolates harbored eae gene, other four harbored tetB gene, and only one isolate exhibited a positive stx2 gene. Conclusion: Our study explored vital methods for identifying E. coli as a harmful pathogen of raw milk using 16S rRNA sequencing, phylogenetic analysis, and detection of virulence factors and antibiotic-resistant genes.http://www.veterinaryworld.org/Vol.14/September-2021/16.pdf16s rrnaantibioticescherichia coliraw milkserologyvirulence |
| spellingShingle | Waleed Younis Sabry Hassan Hams M. A. Mohamed Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance Veterinary World 16s rrna antibiotic escherichia coli raw milk serology virulence |
| title | Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance |
| title_full | Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance |
| title_fullStr | Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance |
| title_full_unstemmed | Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance |
| title_short | Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance |
| title_sort | molecular characterization of escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance |
| topic | 16s rrna antibiotic escherichia coli raw milk serology virulence |
| url | http://www.veterinaryworld.org/Vol.14/September-2021/16.pdf |
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