ABSTRACT
Aims: This study was conducted to detect the presence of oxytetracycline residues in table eggs in Khartoum State and to compare its level with the international acceptable maximum residue limits (MRLs). Study Design: One hundred and eighty table egg samples were randomly collected from 18 sale points in the three localities of Khartoum State, Sudan, (60 eggs from Omdurman, 60 eggs from Khartoum and 60 eggs from Khartoum North). Place and Duration of Study: Samples collected from Khartoum State during August and September, 2015. Methodology: Microbiological inhibition assay was used to screen the presence of antibiotic residues using Bacillus subtilis seeded in nutrient agar. Ninety positive egg samples from the microbiological inhibition assay were analyzed to detect the presence and quantity of oxytetracycline residues using HPLC. Results: Microbiological inhibition assay showed that 50% of the tested samples were positive for antibiotic residues in Omdurman, Khartoum and Khartoum North with 34(18.9%), 28(15.6%), and 28(15.6%) of the antibiotics respectively. HPLC results showed that 63(70%) were positive for oxytetracycline residues 19(10.5%) from Omdurman, 21(11.6%) from Khartoum and 23(12.7%) from Khartoum North. Conclusion: It was concluded that high percentage of table eggs contained oxytetracycline residues above the MRLs (0.2 ppm) that indicated the widespread misuse of oxytetracycline in poultry farms that may cause health hazards to consumers in Khartoum State. Therefore the study recommends compliance of drug withdrawal periods in poultry farms could reduce the incidence of antibiotic residues in consumed eggs.
ABSTRACT
Purpose: Haemorrhagic colitis and haemolytic-uremic syndrome are associated with Shiga-toxin producing Escherichia coli (STEC). There are others DEC (Diarrhoeagenic E. coli) pathotypes responsible for outbreaks and others toxins associated to these. Most clinical signs of disease arise as a consequence of the production of Shiga toxin 1 (Stx1), Stx2 or combinations of these toxins. Other major virulence factors include E. coli haemolysin (hlyA), and intimin, the product of the eaeA gene that is involved in the attaching and effacing adherence phenotype. Materials and Methods: In this study, the PCR assay was used to detect 12 E. coli genes associated with virulence (stx1, stx2, hylA, Flic h7 , stb, F41, K99, sta, F17, LT-I, LT-II and eaeA). Results: A total of 108 E. coli strains were serotyped into 64 typable strains. The investigated strains from the stool, 8/80 (10%) strains were O 164:K, while the 56/110 strains isolated from the urine were O126:K71 (44/110, 40%) and O 86:K 61 (12/110, 11%). The distribution pattern of the detected virulence genes was observed to be in the following order: F17 (10% from the stool and 44% from the urine), Sta (10% from the stool), hylA (10% from the stool and 44% from the urine), Stb (44% from the urine) and stx1 (27% from the urine). The 8 faecal strains encoded a combination of the F17, Sta and hylA genes, while the 56 urine strains encoded a combination of the F17 0+ Stb + hylA (44/110, 40%) and Stx1 only (12/60, 20%). Conclusion: This is the first report on the molecular characterization of E. coli diarrhoeagenic strains in Egypt and the first report on the potential role of E. coli in diarrhoea and urinary tract infections in a localized geographic area where the people engage in various occupational activities.