Masters Dissertation
Poultry is a major reservoir of Salmonella worldwide associated with increasing incidences
of strains producing ESBL enzymes that are capable of inactivating a wide variety of β-
lactam antibiotics. CTX-M ESBLs have been described in S. Typhimurium isolates with
resistance genes located on transferable plasmids. The aim of this study was to determine
the prevalence and antimicrobial resistance of S. Typhimurium, prevalence and characterise
CTX-M-Type ESBL-producing S. Typhimurium in poultry farms in the Copperbelt
Province in Zambia. A cross-section study design was used which involved five districts.
One poultry farm per district was randomly selected for sampling of birds. An overall of
384 faecal samples were analysed for the presence of S. Typhimurium using
microbiological and molecular methods. S. Typhimurium was detected at 17.7% prevalence
in poultry farms of which 12.8% were found harboring the CTX-M-Type ESBL genes.
Antibiotic use, purpose of use, withdrawal period, manure handling, hygiene and biosecurity
were found to be associated with this prevalence. Chingola district had a
prevalence of 7.3% followed by Ndola district with a prevalence of 5.2%, Luanshya
district 2.9%, Kitwe 1.6% and Mufulira 0.8%. Further findings indicated that all the
isolates showed 100% resistance to tetracycline followed by erythromycin with 97.1%,
ampicillin and amoxicillin with 91.2%. A study in Nigeria, reported a prevalence of 16.0%
S. Typhimurium in poultry farms and china reported a prevalence on 17.76% CTX-M-Type
producing Salmonella in foodborne animals which are slightly similar with findings from
this study. Antibiotic resistance to third-generation cephalosporins was at 58.8%
cefotaxime and 54.4% ceftazidime. This could be due to the presence of cefotaximases that
have more hydrolytic activity to cefotaxime than ceftazidime.
Inter-University Council for East Africa (IUCEA)