Antimicrobial susceptibility of enterobacteriacae isolated from intestinal microbiota of residents of the Republic of Guinea and Russia (Saint Petersburg)

Abstract

It is known that resistant Enterobacteriacae strains can be a part of human microbiota. While colonizing the body of a healthy person, resistant strains do not cause diseases, while the healthy person becomes carrier and source of such strains or the resistance genes to the external environment. The aim of the study was to compare the antimicrobial susceptibility of opportunistic Enterobacteriacae isolated from feces of residents of the Republic of Guinea (121 strains) and Russia, Saint Petersburg (897 strains). The antimicrobial susceptibility was determined by the disc-diffusion method according to the national russian Clinical Guideline “Antimicrobial susceptibility testing of microorganisms” using discs and Muller-Hinton agar manufactured by Oxoid. Resistance mechanisms were tested in bacterial strains non-susceptible to beta- lactams using confirmatory phenotypic and molecular tests. Resistant strains were detected significantly more often in the intestinal microbiota of residents of the Republic of Guinea, than of Saint Petersburg (83.5 and 28.7 per 100 strains studied, respectively), including strains with multidrug resistance (47.9 and 11.1, respectively). The residents of the Republic of Guinea have a high frequency of isolation of Enterobacteriacae resistant to “old” antibiotics, which were often used in the 1970s, but rarely used in Russia and other European countries: tetracyclines (63.2), trimethoprim/ sulfamethoxazole (59.5) and aminopenicillins (48.4). The frequency of detection of strains resistant to modern clinically significant antibiotics (extended spectrum cephalosporins, fluoroquinolones, aminoglycosides) was the same in residents of the Republic of Guinea and Saint Petersburg. Resistance to beta-lactams in Enterobacteriacae strains isolated both from the residents of the Republic of Guinea and from Saint Petersburg is due to the same mechanism - the production of beta-lactamases - broad-spectrum and extended spectrum- of various genetic families. This data corresponds to world global trends in the antimicrobial resistance in Enterobacteriacae: resistance to aminopenicillins in E. coli is due to the production of broad-spectrum beta-lactamases TEM-1 (80% of strains from residents of the Republic of Guinea and 86.5% from Saint Petersburg), and resistance to extended spectrum cephalosporins - the production of extended spectrum beta-lactamases of the CTX-M1 genetic group (72.7 and 67.6% respectively). Our research has shown that the intestinal microbiota of the inhabitants of different continents (Europe and Africa) contains the strains (Klebsiella pneumoniae and Escherichia coli) resistant to clinically significant antibiotics (beta-lactams) due to single mechanism globally spread in Enterobacteriacae.