Sensitivity of archival and clinical enterobacteria strains to synthetic GM-CSF active center ZP2 peptide

Abstract

Objective: to study sensitivity of various enterobacterial species to the bactericidal action of the ZP2 synthetic GM-CSF active center peptide after long-term storage. In vitro experiments were carried out with archival archival test strains Escherichia coli K12 (GISK 240367) and E. coli (ATCC 25922), as well as 104 clinical isolates of E. coli (n = 22) and Klebsiella pneumoniae (n = 82) obtained from patients with surgical pathology. The bactericidal effect of the ZP2 peptide (final concentration 10 μg/ml) on microorganisms was assessed by measuring optical density (OD) difference between experimental and control broth cultures after 20 min exposure of bacterial suspensions (5 × 108 CFU/ml) with the ZP2 peptide (in control – with distilled water), added with meat-peptone broth and incubated at 37 °C for 4 hours. The ZP2 peptide effect was presented as Bactericidal Activity Index (BAI, %). It was experimentally found that the archival E. coli test strains as well as most of examined clinical strains of E. coli and K. pneumoniae (95.5 and 97.6%, respectively) showed sensitivity to the bactericidal effect of the synthetic ZP2 peptide (at a final concentration of 10 μg/ml ) with BAI averaging 77.6±3.5 and 82.8±1.6% and its relatively wide variation range 45.8 ... 98.9 and 42.1 ... 99.8%, respectively. The 5-year storage of synthetic ZP2 peptide at 8 °C exerted bactericidal effect on antibiotic-resistant enterobacterial strains. The data obtained can be used to develop ZP2 peptide-based drugs aimed at combating pyo-inflammatory processes caused by antibiotic-resistant E. coli and K. pneumoniae strains.