Toxigenic and Antibiotic-Resistant Bacillus cereus in Raw Cow Milk from Eastern Cape, South Africa: A Potential Public Health Threat
Abstract
1. Introduction
2. Materials and Methods
2.1. Sample Collection and Transportation
2.2. Bacterial Isolation, Identification and Evaluation of Growth at 4 °C
2.3. Extraction of DNA
2.4. Screening for 16S rDNA Gene
2.5. Antimicrobial Susceptibility Testing
2.6. Detection of gyrB, Toxin and Emetic Toxin Genes in B. cereus
Target Gene | Forward Primer (5′–3′) | Reverse Primer (5′–3′) | Annealing Temp (°C) | References |
---|---|---|---|---|
gyrB | BC Forward 5′-GTTTCTGGTGGTTTACATGG-3′ | BC Reverse 5′-TTTTGAGCGATTTAAATGC-3′ | 57 °C | [19,25] |
nheA | nheA forward 5′-TACGCTAAGGAGGGGCA-3′ | nheA reverse 5′-GTTTTTATTGCTTCATCGGCT-3′, 51 °C | 51 °C | [19,26] |
nheB | nheB forward 5′-CTATCAGCACTTATGGCAG-3 | nheB reverse 5′-ACTCCTAGCGGTGTTCC-3′ | 53 °C | [19,26] |
nheC | nheC forward 5′-CGGTAGTGATTGCTGGG-3′ | nheC reverse 5′-CAGCATTCGTACTTGCCAA-3′ | 53 °C | [19,26] |
hblA | HBLA forward 5′-GTGCAGATGTTGATGCCGAT-3′ | HBLA reverse 5′-ATGCCACTGCGTGGACATAT-3′ | 55 °C | [19,26] |
entFM | entFM forward 5′-ATGAAAAAAGTAATTTGCAGG-3′ | entFM reverse 5′-TTAGTATGCTTTTGTGTAACC-3′ | 52 °C | [19,26] |
cytK | CK-F-1859 5′-ACAGATATCGG(GT)CAAAATGC-3′ | CK-R-2668 5′-TCCAACCCAGTT(AT)(GC)CAGTTC-3′ | 58 °C | [19,26] |
Ces | ces forward 5′-GGT GACACATTATCA TATAAGGTG-3′ | reverse 5′GTAAGCGAACCTGTCTGTAAC AACA-3′ | 54 °C | [20,26] |
L1 | L1 forward 5′-AATGGTCATCGGAACTCTAT-3′ | L1 reverse 5′-CTCGCTGTTCTGCTGTTAAT-3′, | 51 °C | [19,26] |
L2 | L2 forward 5′-AATCAAGAGCTGTCACGAAT-3′ | L2 reverse 5′-CACCAATTGACCATGCTAAT-3′ | 51 °C | [19,26] |
2.7. Determination of Emetic Toxin and Enterotoxins
2.8. Data Analysis and Visualization
3. Results
3.1. Isolation and Toxin Gene Profiling of B. cereus from Raw Milk
3.2. Antibiotic Susceptibility Profile of B. cereus from Raw Milk
4. Discussion
4.1. Isolation and Toxin Gene Profiling of B. cereus from Raw Milk
4.2. Antibiotic Susceptibility Profile of B. cereus from Raw Milk
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Categories | Antibiotic | Number of Isolates N (%) | |||
---|---|---|---|---|---|
Concentration (µg) | Resistant | Intermediate | Susceptible | ||
β-lactam antibiotics | Ampicillin | 10 | 160 (64) | 90 (36) | 0 (0) |
Amoxicillin-clavulanic acid | 20/10 | 190 (76) | 17 (7) | 43 (17) | |
Cephalothin | 30 | 202 (81) | 22 (9) | 26 (10) | |
Cefepime | 30 | 189 (76) | 0 (0) | 61 (24) | |
Cefotetan | 30 | 140 (56) | 20 (3) | 102 (41) | |
Oxacillin | 1 | 28 (11) | 0 (0) | 222 (89) | |
Aminoglycosides | Gentamicin | 10 | 250 (100) | 0 (0) | 0 (0) |
Kanamycin | 30 | 215 (86) | 30 (12) | 5 (2) | |
Macrolides | Erythromycin | 15 | 235 (94) | 10 (4) | 5 (2) |
Telithromycin | 15 | 226 (90) | 0 (0) | 24 (10) | |
Glycopeptides | Vancomycin | 30 | 110 (44) | 0(0) | 140 (56) |
Quinolones | Ciprofloxacin | 5 | 237 (95) | 0 (0) | 13 (5) |
Amphenicols | Chloramphenicol | 30 | 250 (100) | 0 (0) | 0 (0) |
Tetracyclines | Tetracycline | 30 | 226 (90) | 0 (0) | 24 (10) |
Rifamycins | Rifampicin | 5 | 6 (2) | 0 (0) | 244 (98) |
Folic acid inhibitors | Trimethoprim-sulfamethoxazole | 1.25/23.75 | 224 (89) | 4 (2) | 22 (9) |
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Green, E.; Ogofure, A.G. Toxigenic and Antibiotic-Resistant Bacillus cereus in Raw Cow Milk from Eastern Cape, South Africa: A Potential Public Health Threat. Microorganisms 2025, 13, 2253. https://doi.org/10.3390/microorganisms13102253
Green E, Ogofure AG. Toxigenic and Antibiotic-Resistant Bacillus cereus in Raw Cow Milk from Eastern Cape, South Africa: A Potential Public Health Threat. Microorganisms. 2025; 13(10):2253. https://doi.org/10.3390/microorganisms13102253
Chicago/Turabian StyleGreen, Ezekiel, and Abraham Goodness Ogofure. 2025. "Toxigenic and Antibiotic-Resistant Bacillus cereus in Raw Cow Milk from Eastern Cape, South Africa: A Potential Public Health Threat" Microorganisms 13, no. 10: 2253. https://doi.org/10.3390/microorganisms13102253
APA StyleGreen, E., & Ogofure, A. G. (2025). Toxigenic and Antibiotic-Resistant Bacillus cereus in Raw Cow Milk from Eastern Cape, South Africa: A Potential Public Health Threat. Microorganisms, 13(10), 2253. https://doi.org/10.3390/microorganisms13102253