Distribution of virulence genes and antimicrobial susceptibility of Salmonella isolated from dogs and chickens in Zambia

The present study was conducted to investigate the distribution of virulence genes and the antimicrobial susceptibility of Salmonella isolated from dogs and chickens. A total of 379 samples were examined with 41 Salmonella isolates being cultured with 18 (7.4%; 95% CI: 4.57-11.6) and 23 (16.9%; 95% CI: 11.2-24.5) isolates from dog and chicken, respectively. On serotyping, the isolates belonged to Group B, C, D and E, while 6 isolates from dog were untypeable. The Polymerase chain reaction (PCR) assay was carried out to detect Salmonella invA, invF and sipC virulence genes. A varying distribution of the targeted virulence genes was observed amongst the isolates. InvA was found in all the 41 strains, invF was found among 3 dog and 10 chicken isolates with sipC being observed among 2 dog and chicken isolates respectively. On antimicrobial susceptibility, dog isolates were susceptible to amoxicillin (100%) and nitrofurantoin (94.4%), whereas chicken isolates showed susceptibility to nitrofurantoin (100%), amoxicillin (95.7%), ampicillin and tetracycline (82.6%). It was concluded that dogs and chickens are important carriers of invasive Salmonella in Zambia with a multiple antimicrobial drug resistance pattern. This may be a potential source of human salmonellosis which is difficult to manage by antibiotic therapy.