Isolation and molecular identification of multidrug-resistant strains isolated from mastitic cows in Egypt.

BACKGROUND

Mastitis is a common disease that affects the dairy sector globally because it not only impacts animal welfare but can also lead to significant financial losses.

AIM

This study examined the phenotypic and genotypic profiles of the multidrug-resistant (MDR) () strains that were isolated from mastitic cows in Egypt to detect their pattern of antibiotic resistance.

METHODS

Four hundred native breed lactating cows were evaluated to identify clinical and subclinical mastitis. A total of 100 mastitic milk samples (64 from clinical mastitis and 36 from subclinical mastitis) were collected for phenotypic isolation and identification of coliform bacteria. isolates were identified through their morphological features, Gram staining, and biochemical tests. The identified strains were examined against various antibiotics using disk diffusion methods. All strains were analyzed for the antibiotic resistance genes Streptomycin (aadA), blaTEM, Tetracycline (tetA), Sulfonamides, and qnrA using PCR.

RESULTS

Among 400 examined dairy cows, the prevalences of clinical and subclinical mastitis were 16% and 9%, respectively. Bacteriological isolation of coliform bacteria from mastitic milk samples revealed that was the most prevalent bacterium. Among 10 isolates of biochemically verified strains, 8 (80%) were MDR across 6 distinct classes of antibiotics. All recovered strains exhibited higher resistance to Amoxicillin, Cefotaxime, Sulphamethaxzole/Trimethoprim, and Tetracycline. High susceptibility was noticed to Ciprofloxaccin, Amoxicillin+Clavulinic, Streptomycin, Gentamicin, Chloramphenicol, and Colistin. The TEM gene was among the most common antibiotic resistance genes found in isolates (100%). Furthermore, the genotypes encoding resistance to , A, and Sulfonamides were 50%, 40%, and 50%, respectively.

CONCLUSION

MDR pathogenic strains are common in mastitic dairy cows in Egypt, and preventive actions must be implemented to avoid serious public health concerns.