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Eid RH, Aref NE, Ibrahim ES. Phenotypic diagnosis and genotypic identification of Bacillus cereus causing subclinical mastitis in cows. Vet World 2023; 16:888-894. [PMID: 37576758 PMCID: PMC10420715 DOI: 10.14202/vetworld.2023.888-894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/14/2023] [Indexed: 08/15/2023] Open
Abstract
Background and Aims Bovine mastitis is a disease that affects dairy cows and impacts the global dairy industry. Bacillus spp. can infect the mammary gland during lactation, intramammary treatment, or dry cow therapy. This study aimed to isolate and identify Bacillus spp. in raw milk samples from cows with subclinical mastitis from dairy farms in Beheira, Giza, Alexandria, and Menoufia Governorate, Egypt. We also investigated their antibiotic sensitivity and detected the enterotoxigenic and antibiotic resistance genes. Materials and Methods A total of 262 milk samples (15-20 ml each) were examined microscopically, biochemically, and phenotypically. A polymerase chain reaction was used for genotypic identification and detecting antibiotic-resistance and enterotoxigenic genes. Antibiotic sensitivity was tested using the agar well diffusion test. Results Bacillus cereus was identified in 47.7% of samples. Nhe and hblD enterotoxin genes were found in 93.64% (103/110) and 91.82% (101/110) of the samples, respectively. Tetracycline and β-lactam antibiotic-resistance genes were present in 0% (0/110) and 98.18% (108/110), respectively, of the samples. All isolates were resistant to cefepime, cefixime, and oxacillin, while they were susceptible to amoxicillin-clavulanic, chloramphenicol, ampicillin/sulbactam, and levofloxacin. Conclusion These results highlight the need to promote awareness regarding B. cereus, the most common pathogen causing mastitis in Egyptian dairy cows. We also emphasized that antibiotic misuse during mastitis is a potential public health threat.
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Affiliation(s)
- Rasha H. Eid
- Department of Mastitis and Neonatal Disease, Animal Reproduction Research Institute, Agriculture Research Center, Giza, Egypt
| | - Noha E. Aref
- Department of Mastitis and Neonatal Disease, Animal Reproduction Research Institute, Agriculture Research Center, Giza, Egypt
| | - Eman S. Ibrahim
- Department of Microbiology and Immunology, National Research Centre, Giza, Egypt
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Meng L, Zhang R, Dong L, Hu H, Liu H, Zheng N, Wang J, Cheng J. Characterization and spoilage potential of Bacillus cereus isolated from farm environment and raw milk. Front Microbiol 2022; 13:940611. [PMID: 36177462 PMCID: PMC9514233 DOI: 10.3389/fmicb.2022.940611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Bacillus cereus sensu lato (B. cereus sl) is important spoilage bacteria causing milk structure and flavor changes and is ubiquitous in the environment. This study addresses the biodiversity, toxicity, and proteolytic activity of B. cereus sl from 82 environmental samples and 18 raw bovine milk samples from a dairy farm in the region of Tianjin. In sum, 47 B. cereus sl isolates were characterized through biochemical tests, 16S rRNA gene sequencing, and panC gene analysis. Fourteen sequence types (STs) of B. cereus sl were found in raw bovine milk samples, and five new STs (ST2749, ST2750, ST2751, ST2752, and ST2753) were identified in this study. ST1150 was the dominant ST, associated with fecal, air, drinking water, teat skin, teat cup, and teat dip cup. The results of toxin gene analyses showed that 12.77% and 8.51% of isolates carried hblACD and nheABC operons, respectively. In addition, the detection rate of emetic cesB gene was 21.28%. B. cereus sl demonstrated high spoilage potentials even at 7°C, which has the proteolytic activity of 14.32 ± 1.96 μmol of glycine equivalents per ml. Proteolytic activities were significantly (p < 0.05) decreased after the heat treatment. The residual activity of protease produced at 7°C was significantly higher than that produced at 25°C and 37°C after treatment at 121°C for 10 s and 135°C for 5 s (p < 0.01). Together, the results provide insights into the characteristics of B. cereus sl from farm environment and raw bovine milk and revealed that B. cereus sl contamination should also be monitored in raw milk for ultra-high temperature (UHT) products. This knowledge illustrates that strict cleaning management should be implemented to control B. cereus sl and assure high-quality milk products.
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Affiliation(s)
- Lu Meng
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ruirui Zhang
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
| | - Lei Dong
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Precision Livestock and Nutrition Laboratory, Teaching and Research Centre (TERRA), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Haiyan Hu
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huimin Liu
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Nan Zheng
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaqi Wang
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Jiaqi Wang
| | - Jianbo Cheng
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
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Yehuda A, Slamti L, Malach E, Lereclus D, Hayouka Z. Elucidating the Hot Spot Residues of Quorum Sensing Peptidic Autoinducer PapR by Multiple Amino Acid Replacements. Front Microbiol 2019; 10:1246. [PMID: 31231335 PMCID: PMC6568020 DOI: 10.3389/fmicb.2019.01246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022] Open
Abstract
The quorum sensing (QS) system of Bacillus cereus, an opportunistic human pathogen, utilizes the autoinducing PapR peptide signal that mediates the activation of the pleiotropic virulence regulator PlcR. A set of synthetic 7-mer PapR-derived peptides (PapR7; ADLPFEF) have been shown to inhibit efficiently the PlcR regulon activity and the production of virulence factors, reflected by a loss in hemolytic activity without affecting bacterial growth. Interestingly, these first potent synthetic inhibitors involved D-amino acid or alanine replacements of three amino acids; proline, glutamic acid, and phenylalanine of the heptapeptide PapR. To better understand the role of these three positions in PlcR activity, we report herein the second generation design, synthesis, and characterization of PapR7-derived combinations, alternate double and triple alanine and D-amino acids replacement at these positions. Our findings generate a new set of non-native PapR7-derived peptides that inhibit the PlcR regulon activity and the production of virulence factors. Using the amino acids substitution strategy, we revealed the role of proline and glutamic acid on PlcR regulon activation. Moreover, we demonstrated that the D-Glutamic acid substitution was crucial for the design of stronger PlcR antagonists. These peptides represent potent synthetic inhibitors of B. cereus QS and constitute new and readily accessible chemical tools for the study of the PlcR system. Our method might be applied to other quorum sensing systems to design new anti-virulence agents.
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Affiliation(s)
- Avishag Yehuda
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Leyla Slamti
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Einav Malach
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Zvi Hayouka
- Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot, Israel
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