Prevalence of multidrug resistant Salmonella spp. in dairy products with the evaluation of the inhibitory effects of ascorbic acid, pomegranate peel extract, and D-tryptophan against Salmonella growth in cheese.

The present study aimed at investigation of the prevalence and antimicrobial susceptibility of Salmonella spp. in the retailed dairies in Egypt. Besides, the inhibitory effects of some natural additives, including, ascorbic acid, pomegranate peel extract, and D-tryptophan against the isolated Salmonella were evaluated using soft cheese as a food matrix. To reach to this end, different Egyptian retail dairy products were investigated; 30 samples of each product were analyzed. Kariesh cheese samples had the highest Salmonella prevalence rate at 16.67%, followed by market raw milk, and bulk tank milk at 6.66% each, and white soft cheese at 3.33%. Serological examination exhibited 5 different Salmonella serotypes, namely S. Enteritidis, S. Typhimurium, S. Virchow, S. Larochelle, and S. Apeyeme. Antimicrobial susceptibility testing indicated that 100% of the isolates possessed resistance to erythromycin, oxacillin, and nalidixic acid. Some isolates of S. Typhimurium and S. Enteritidis were resistant to all 14 examined antibiotics. Isolates of S. Enteritidis obtained in this study were used to contaminate the freshly prepared soft cheese. Treatment of the artificially Salmonella-contaminated soft cheese with pomegranate peel extract, ascorbic acid, and D-tryptophan revealed a significant (P < 0.05) reduction in Salmonella growth in a dose-dependent manner. Therefore, the examined natural additives can be viewed as a promising new line of preservatives for dairy industry.

Ringworm in calves: risk factors, improved molecular diagnosis, and therapeutic efficacy of an Aloe vera gel extract.

BACKGROUND: Dermatophytosis in calves is a major public and veterinary health concern worldwide because of its zoonotic potential and associated economic losses in cattle farms. However, this condition has lacked adequate attention; thus, to develop effective control measures, we determined ringworm prevalence, risk factors, and the direct-sample nested PCR diagnostic indices compared with the conventional methods of dermatophytes identification. Moreover, the phenolic composition of an Aloe vera gel extract (AGE) and its in vitro and in vivo antidermatophytic activity were evaluated and compared with those of antifungal drugs. RESULTS: Of the 760 calves examined, 55.79% (424/760) showed ringworm lesions; 84.91% (360/424) were positive for fungal elements in direct-microscopy, and 79.72% (338/424) were positive in culture. Trichophyton verrucosum was the most frequently identified dermatophyte (90.24%). The risk of dermatophytosis was higher in 4-6-month-old vs. 1-month-old calves (60% vs. 41%), and in summer and winter compared with spring and autumn seasons (66 and 54% vs. 48%). Poor hygienic conditions, intensive breeding systems, animal raising for meat production, parasitic infestation, crossbreeding, and newly purchased animals were statistically significant risk factors for dermatophytosis. One-step PCR targeting the conserved regions of the 18S and 28S genes achieved unequivocal identification of T. verrucosum and T. mentagrophytes in hair samples. Nested-PCR exhibited an excellent performance in all tested diagnostic indices and increased the species-specific detection of dermatophytes by 20% compared with culture. Terbinafine and miconazole were the most active antifungal agents for dermatophytes. Gallic acid, caffeic acid, chlorogenic acid, cinnamic acid, aloe-Emodin, quercetin, and rutin were the major phenolic compounds of AGE, as assessed using high-performance liquid chromatography (HPLC). These compounds increased and synergized the antidermatophytic activity of AGE. The treated groups showed significantly lower clinical scores vs. the control group (P < 0.05). The calves were successfully treated with topical AGE (500 ppm), resulting in clinical and mycological cure within 14-28 days of the experiment; however, the recovery was achieved earlier in the topical miconazole 2% and AGE plus oral terbinafine groups. CONCLUSIONS: The nested PCR assay provided a rapid diagnostic tool for dermatophytosis and complemented the conventional methods for initiating targeted treatments for ringworm in calves. The recognized antidermatophytic potential of AGE is an advantageous addition to the therapeutic outcomes of commercial drugs.