Peptide Spectra Analysis of DNA Starvation/Stationary Phase Protection-Like Protein Found in Hospital-Acquired ESBL Producing Escherichia coli by MALDI-TOF Technique

The present study aimed to investigate the hospital-acquired Extended Spectrum β-Lactamase production (ESBL) producing Escherichia coli, to identify the significant ESBL peptide spectra after exposure to ceftazidime and amoxicillin/clavulanic acid, and to identify the resistant peptide spectra after exposure to ciprofloxacin. ESBL production and the minimal inhibitory concentration of ciprofloxacin were investigated using the Epsilometer strip test. Their colonies were collected to analyze the peptide spectra by VITEK® Mass Spectrometry. The significant difference in spectrum intensity for suspected ESBL peptide spectra, and DNA starvation/stationary phase protection (Dps) -like peptide spectra were also determined. Among 228 isolates, the high ESBL-producing E. coli which exhibited high ciprofloxacin resistance was demonstrated as 22.63%. The significant reduction of spectrum intensity after exposure to ceftazidime and amoxicillin/clavulanic acid was only detected at spectrum 9714 Da in the high ESBL-producing group (P ≤0.001). Among four selected high ESBL producers, only one significant spectrum located at 9063 Da was detected in the high ciprofloxacin-resistant group (P ≤0.001) after being exposed to ceftazidime and ciprofloxacin. The highest percentage increase of spectrum 9063 Da was 69.42%. Multidrug resistance was demonstrated in the tested E. coli isolates, especially β-lactam resistance which may be caused by their ESBL production. It may be said that the peptide spectrum located at 9714, and 9063 Da were suspected as the ESBL indicative peptide spectrum in the high ESBL producers, and as the Dps indicative peptide spectrum in the high ciprofloxacin-resistant isolates. Keywords: Peptide spectra analysis, DNA starvation/stationary phase protection like protein, Hospital-acquired infection, Extended spectrum β-lactamase, Escherichia coli, Matrix-Assisted Laser Desorption Ionization-Time Of Flight