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Characterization of multidrug-resistant potential pathogens isolated from milk and some dairy products in Egypt
Dina Ashraf1, Rabee A Ombarak2, Ahmed Samir1
1Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt.
Objective:
This study aimed to explore the incidence and antimicrobial resistance (AMR) of Escherichia coli, Staphylococcus aureus, and Bacillus cereus in raw milk and some Egyptian dairy products, namely Kariesh cheese and rice with milk.
Material And Methods:
112 samples (70 raw milk, 30 Kariesh cheese, and 12 rice with milk) were randomly collected from different districts in Cairo and Giza, Egypt. The samples were examined for E. coli, S. aureus, and B. cereus presence. The susceptibility of the obtained isolates was tested against 11 antimicrobials using the disk diffusion method, and further, the presence of AMR genes was examined.
Results:
The incidences of E. coli, S. aureus, and B. cereus were 69.64%, 12.5%, and 16.7% in the examined samples, respectively. The antibiogram indicated that E. coli isolates (n = 60) were resistant to gentamycin (73.33%), ampicillin (AM, 53.3%), and cefotaxime (CTX, 16.66%). Multidrug-resistant (MDR) E. coli strains (n = 5) were tested for β-lactams resistance genes. blaTEM was detected in all isolates, and two of them additionally carried blaCTX-M. Staphylococcus aureus isolates (n = 10) were resistant to AM (100%), followed by tetracycline (TE), CTX, and gentamycin (60% each). All MDR S. aureus strains (n = 4) carried blaZ and tetK, and three of them additionally carried aac(6')-aph (2''). Bacillus cereus isolates (n = 30) showed resistance to AM (100%), amoxicillin (20%), and TE (6.66%). bla and tetA genes were detected in all MDR B. cereus isolates (n = 6).
Conclusion:
Our findings denote the high incidence of potential health hazards in raw milk and some of its products and the existence of AMR bacteria, including MDR strains, which can cause human illnesses that are difficult to treat.
Insights
Antimicrobial resistance (AMR) in raw milk and dairy products like Kariesh cheese is a significant health concern. This study found high incidences of resistant Escherichia coli, Staphylococcus aureus, and Bacillus cereus, including multidrug-resistant strains.
Area of Science:
- Microbiology and Food Safety
- Antimicrobial Resistance (AMR)
- Public Health
Background:
- Raw milk and dairy products can harbor pathogenic bacteria.
- Antimicrobial resistance (AMR) in foodborne pathogens poses a growing threat to public health.
- Surveillance of AMR in commonly consumed food products is crucial.
Purpose of the Study:
- To determine the incidence of Escherichia coli, Staphylococcus aureus, and Bacillus cereus in Egyptian raw milk, Kariesh cheese, and rice with milk.
- To investigate the antimicrobial susceptibility patterns of these bacterial isolates.
- To identify the presence of specific antimicrobial resistance genes in multidrug-resistant (MDR) strains.
Main Methods:
- Collection and microbiological examination of 112 samples (raw milk, Kariesh cheese, rice with milk) from Cairo and Giza, Egypt.
- Disk diffusion method to assess the susceptibility of bacterial isolates to 11 antimicrobials.
- Molecular detection of AMR genes (e.g., blaTEM, blaCTX-M, blaZ, tetK, tetA, aac(6')-aph(2'')) in MDR isolates.
Main Results:
- High incidences of E. coli (69.64%), S. aureus (12.5%), and B. cereus (16.7%) were detected.
- Significant resistance was observed: E. coli to gentamycin and ampicillin; S. aureus to ampicillin, tetracycline, cefotaxime, and gentamycin; B. cereus to ampicillin.
- MDR strains of all three bacteria were identified, carrying various resistance genes, including blaTEM, blaCTX-M, blaZ, tetK, and tetA.
Conclusions:
- Raw milk and dairy products in Egypt harbor bacteria with concerning AMR profiles.
- The presence of MDR strains highlights a potential risk for public health, leading to difficult-to-treat infections.
- Continuous monitoring and control strategies are essential to mitigate the spread of AMR in the food chain.
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