Tapalski D.V.1, Bonda N.A.2, Lagun L.V.1
Microbiological monitoring system of extensively drug-resistant and pandrug-resistant bacterial pathogens determining the sensitivity to antibiotic combinations
1Gomel State Medical University, Gomel, Republic of Belarus
2Gomel Regional Center of Hygiene, Epidemiology and Public Health, Gomel, Republic of Belarus
Vestnik VGMU. 2018;17(1):50-58.
Objectives. To organize the system of microbiological monitoring based on the detection of epidemiologically significant antibiotic-resistant isolates and determination of their sensitivity to antibiotics and their combinations.
Material and methods. Carbapenemases genes detection by means of real-time PCR method and determination of minimal inhibitory antibiotic concentrations with the help of twofold serial broth dilutions method were carried out for 130 extensively drug-resistant Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii clinical strains isolated in 2016-2017 years in 21 health care institutions of Gomel Region. In addition, for each microorganism sensitivity to 11 double antibiotic combinations was determined by testing the bactericidal activity of various concentrations.
Results. 8 isolates (9,8%) with resistance to all antibiotics (with colistin MIC of 4 and more mcg/ml) and 72 isolates (87,2%) sensitive only to colistin were detected among 82 extensively drug-resistant P.aeruginosa isolates. Most of the strains of A.baumannii and K.pneumoniae included in the study remained sensitive only to colistin and tigecycline. The carbapenemases production was detected in 11,0% of the P.aeruginosa isolates (metallo-β-lactamase VIM); all isolates of A.baumannii (carbapenemase OXA-23 – in 2,7% of the isolates, carbapenemase OXA-40 – in 97,3% of the isolates); 30,6% of the K.pneumoniae isolates (carbapenemase OXA-48 – in 25,0% of the isolates, metallo-β-lactamase NDM – in 5,6% of the isolates). The bactericidal activity of all combinations with the inclusion of colistin for the majority of the investigated strains of K.pneumoniae and A.baumannii has been revealed. The combinations of meropenem-colistin and imipenem-colistin demonstrated the greatest activity against P.aeruginosa (bactericidal activity was detected for 82,9% and 89,0% of the isolates).
Conclusions. It has been shown that the extensive antibiotic resistance of A.baumannii and K.pneumoniae is associated with the production of carbapenemases. Antibiotic combinations, effective against extensively antibiotic-resistant microorganisms have been found.
Key words: Klebsiella, Pseudomonas, Acinetobacter, antibiotic resistance, antibiotic combinations, carbapenemases.
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Information about authors:
Tapalski D.V. – Candidate of Medical Sciences, associate professor, head of the Chair of Medical Microbiology, Virology and Immunology, Gomel State Medical University;
Bonda N.A. – doctor-bacteriologist of the Microbiological Laboratory, Gomel Regional Centre of Hygiene, Epidemiology and Public Health;
Lagun L.V. – Candidate of Medical Sciences, associate professor of the Chair of Medical Microbiology, Virology and Immunology, Gomel State Medical University.