Background: Antibiotic tolerance (AT) represents one of the causes of the phenomenon of antibiotic resistance that allows escape of non-replicating metabolically inert microorganisms (persisters) from any antibiotics attack because molecular targets of antibiotics are lacking thereby creating the potential for chronic infections.
Aims: Determine the heterogeneity of the strains of opportunistic pathogens E. coli and P. aeruginosa isolates from children with hematologic malignancies containing bacterial persisters that cause the AT phenomenon.
Methods: Children with hematological malignancies were divided into 2 groups according to the intensity of antibiotic treatment of infectious complications. Ciprofloxacin-induced persisters were quantitatively determined in the biological materials obtained from sick children.
Results: Within the clinical isolates of E. coli and P. aeruginosa, about a third of the strains belong to high-persisting. The numbers of persistent forms of bacteria did not correlate with a minimal inhibitory concentration values ciprofloxacin (r=0.148, n=25, p>0.05). Interestingly, higher level of formation of persistent E. coli and P. aeruginosa, is associated with higher frequencies of infection attacks, massive antibiotic use and unfavorable course of the disease in children.
Conclusions: Therefore, detecting the persistent forms of bacterial pathogens including those associated with the health-care associated infection, specifically, in immunocompromised patients, should be included into the contemporary algorithms of microbiological observation and monitoring of patients and intrahospital environment.