Background: Escherichia coli with its large range of pathologies is a major cause of human
morbidity and mortality around the world. The increasing prevalence of bacteria resistant to
even the most current arsenal of antibiotics is a serious concern for public health globally. The resistant
bacteria which cause human infection are thought to emerge in food and animals.
Objective: Our goal was to study the proteome of an extended-spectrum β-lactamase (ESBL)-
producing Escherichia coli, SU03, strain recovered from faecal samples of pigs slaughtered for human
Method: A full proteomic survey of this strain was made by two-dimensional electrophoresis identifying
proteins by MALDI-TOF/MS.
Results: This strain exhibited ciprofloxacin resistance associated with mutations in type II topoisomerase
structural gene GyrA (Ser83Leu + Asp87Asn) and ParC (Ser80Ile). We studied how the
proteome of this strain responded to stress by applying double the minimum inhibitory concentration
of ciprofloxacin. The hydrolase L-asparaginase was overexpressed when SU03 was cultured with
double the minimum inhibitory concentration of ciprofloxacin.
Conclusion: The abundance of this hydrolase may lead to a diverse secondary response by influencing
in the production of other proteins or directly mediating ciprofloxacin resistance. Further research
should determine how this enzyme contributes to ciprofloxacin resistance.