Antimicrobial resistance (AMR) is a major concern in developing countries. Uganda is one of many developing countries that are beginning to implement a surveillance program countrywide to monitor AMR within the animal, environmental, and human sectors. Not only is there a concern for AMR, but the emergence of multidrug resistance (MDR) of Salmonella is also becoming a major One Health problem. Few new drugs are being produced. When current treatments fail, new antimicrobials for treatment of these microorganisms are limited. In Salmonella, AMR genes are usually found on plasmids that are transferable. Most plasmids that carry resistance are conjugative plasmids, promoting the transfer of DNA from cell to cell. Class I Integrons are located on transposable plasmids and are known to transfer AMR through an assortment of gene cassettes. Extended-spectrum β-lactamases (ESBLs) are also known to encode genes located on integrons and transposons. ESBLs confer resistance to third generation cephalosporins, a drug of choice for treatment of Salmonella infections. ESBLs are now reported in Enterobacteriaceae all over the world. Examples of common ESBLs include blaCTX-M, blaOXA, blaTEM, blaCMY, and blaSHV. It has been reported that ESBLs evolved from the Kluverya species chromosome by mutation and gene transposition. In our previous study, we phenotypically characterized Salmonella from cattle and poultry farms within the Wakiso District of Uganda. Based on the high prevalence of MDR in the isolates collected we continued investigating at the molecular level. For the Salmonella isolates, we wanted to characterize genotypes by first analyzing the relatedness of the isolates with pulse field gel electrophoresis (PFGE). Next, we wanted to look to see which DNA plasmids were present. We looked at 28 replicon plasmids and the Class 1 Integron, Int1. The Salmonella isolates were also screened for ESBL genes based on their resistant profiles.
Objective:
Determine the AMR phenotypes and genotypes of Salmonella isolates recovered from cattle and poultry farms in the Wakiso District of Uganda.