Plasmid replicons and B-lactamase-encoding genes of multidrug- resistant Escherichia coli isolated from humans and food animals in Lagos, Southwest Nigeria

Authors: ADENIPEKUN, EYITAYO - University Of Lagos; Jackson, Charlene; RAMADAN, HAZEM - Mansoura University; IWALOKUN, BAMIDELE - University Of Lagos; Frye, Jonathan; Barrett, John; Hiott, Lari; Woodley, Tiffanie; House, Sandra; MCMILLAN, ELIZABETH - University Of Georgia; SHARMA, POONAM - Orise Fellow; OLUWADUN, AFOLABI - University Of Lagos

Submitted to: Microbial Drug Resistance
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/7/2019
Publication Date: 12/4/2019
Citation: Adenipekun, E., Jackson, C.R., Ramadan, H., Iwalokun, B., Frye, J.G., Barrett, J.B., Hiott, L.M., Woodley, T.A., House, S.L., Mcmillan, E., Sharma, P., Oluwadun, A. 2019. Plasmid replicons and B-lactamase-encoding genes of multidrug- resistant Escherichia coli isolated from humans and food animals in Lagos, Southwest Nigeria. Microbial Drug Resistance. https://doi.org/10.1089/mdr.2018.0305.
DOI: https://doi.org/10.1089/mdr.2018.0305

Interpretive Summary: Beta-lactam antibiotics are the most commonly used class of antibiotics. Production of ß-lactamases has been reported as one of the most common mechanisms of resistance to these antibiotics and has played a significant role in the global spread of resistance particularly in the community and hospital settings as well as in agriculture and the environment. In this study, multidrug resistant Escherichia coli from food animals and humans from Nigeria were analyzed for the presence of Beta-lactamase encoding genes and plasmids which may harbor those genes. A subset of isolates were also tested to determine if the plasmid-associated genes were able to transfer among E. coli. Results showed that Beta-lactamase genes were prevalent in multidrug resistant E. coli from both humans and animals and also contained multiple, diverse plasmids. As the plasmid-associated genes were mobile, they are likely to continue disseminating among E. coli and facilitating transfer of associated Beta-lactamase genes in this region. This information will assist in understanding and monitoring the spread of multidrug resistant E. coli producing Beta-lactamases and plasmid prevalence among food animal and community isolates in Nigeria important to both human and animal health. This information is useful for policy makers and scientists as they develop prevention and control strategies for combating antimicrobial resistance in resource-limited countries.

Technical Abstract: In our previous study, antimicrobial susceptibility profiling and molecular characterization on a large collection of Escherichia coli from humans and food animals from Lagos, Nigeria was done. As resistance to the Beta-lactam class of antibiotics has become a worldwide problem, the multidrug resistant (MDR) human (n=243) and food animal (n=211) isolates were further tested in the present study to characterize potential Beta-lactamase encoding genes and plasmid replicons. Of the seven Beta-lactamase encoding genes tested, four (blaCMY, blaCTX, blaOXA, and blaTEM) were detected with blaCMY identified in the majority of isolates from humans (98/243; 40.3%) and animals (92/211%; 43.3%); none of the isolates were positive for blaKPC, blaNDM, or blaSHV. Of the 25 different plasmid replicon types tested by PCR, 13 and 17 different replicons were identified using a subset of MDR E. coli from humans (n=48) and animals (n=96), respectively. Replicon types FIB and X2 were detected in equal numbers (2/48; 4.2% each) from human isolates while type Y (16/96; 16.7%) was the most common type from animals. Only two replicon types, FIB and Y, were detected in both groups; all other types were confined to one group or the other, but not both. Using conjugation, replicon type Y, present in three donors, transferred in all three instances whereas FIA transferred in 75% (3/4) of the matings and FII in 60% (3/5). This study showed that Beta-lactamase genes were prevalent in MDR E. coli from both humans and animals in Nigeria and also contained diverse plasmid replicons. As the replicon-associated genes were mobile, they are likely to continue disseminating among E. coli and facilitating transfer of associated Beta-lactamase genes in this region.