Molecular identification of tetracycline resistance genes in Escherichia coli isolates from internal organs of swine sold on Abakaliki, Nigeria.

Background: Swine is one of the major sources of protein to humans worldwide; antimicrobial-resistant Escherichia coli has become a global public health challenge affecting both humans and livestock due to the presence of tetracycline resistance genes.

Aim: This study focused on molecular identification of tetracycline resistance genes (tet A and B) in E. coli isolates from internal organs of swine sold in a slaughterhouse at Abakaliki, Ebonyi State, Nigeria.

Methods: A total of 75 internal organs of swine samples were collected from slaughterhouses. Standard microbiological procedures were employed to evaluate the samples bacteriologically. Using the disk diffusion method, antibiotic susceptibility testing was conducted on E. coli against specific classes of antibiotics, and the multiple antibiotic resistance index was calculated. The polymerase chain reaction was utilized for the molecular identification of the tetracycline resistance genes, specifically tet A and B.

Results: Out of the 75 samples analyzed, 24 of 75 were positive for E. coli with an overall prevalence of 24/75 (32.0%). The small intestine and colon had higher percentages of E. coli isolates 6/15 (40.0%). However, E. coli isolates were resistant to erythromycin, tetracycline, and ampicillin which ranged from 20.0% to 75.0%, and susceptible to gentamycin and ciprofloxacin at a range of 75.0%-100.0%. Exactly, 8 (33.3%) isolates were both multidrug and tetracycline-resistant. The presence of tet A 6/8 (75.0%), tet B 5/8 (62.5%), and tet A and B 4/8 (50.0%) was reported.

Conclusion: Multidrug and tetracycline resistance genes have been observed in E. coli isolated from internal organs of swine and are of public health concern.