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Species composition and molecular-genetic characteristics of antibiotic-resistant strains of gram negative bacteria isolated from patients of a hospital’s urology department
DOI: https://dx.doi.org/10.18565/urology.2018.1.77-83
B.U. Shalekenov, A.L. Bissekenova, B.A. Ramazanova, D.A. Adambekov, S.B. Shalekenov
1 Kazakh Medical University of Continuing Education, Almaty, Kazakhstan; 2 S. D. Asfendiyarov Kazakh National Medical University, Almaty, Republic of Kazakhstan; 3 I.K. Akhunbaev Kyrgyz State Medical Academy, Bishkek, Kyrgyz Republic
Aim: To analyze the composition and molecular mechanisms of antibiotic resistance of Gram-negative bacteria - pathogens of urinary tract infections (UTIs) in adult patients living in the city of Almaty.
Materials and methods. The study examined the etiological composition and antibiotic susceptibility of clinically significant isolates of bacteria and fungi (≥ 103) isolated from the urine of the patients of the Department of Urology of the Almaty city Central Clinical Hospital No. 12. The production of extended-spectrum beta-lactamases (ESBL) in antibiotic-resistant strains was determined using a phenotypic method with the double disk test. Detection of class A genes for cultures with confirmed ESBL phenotypes (TEM-1, CTX-M1, SHV, OXA) and carbapenemases of class B metallo-β-lactamases (VIM-2) genes was performed by PCR.
Results. Among the isolates obtained from patients, the species of Enterobacteriaceae family in the etiological composition of the UTI pathogens comprised 44.8% including E. coli (31%), K. pneumoniae (4.6%). The most effective drugs against all types of Enterobacteria were carbapenems (96.3-100%). E.coli showed highest sensitivity to nitrofurantoin (96.3%), amikacin (92.6%) and cefoxitin (81.5%). The high rate of resistance to III-IV generation cephalosporins among of E. coli (44.4%) and K. pneumoniae (50%) species was due to the production of ESBL types CTX-M1 and OXA. The proportion of non-fermenting Gram-negative bacteria in the etiological composition of UTI pathogens was 3.5%. Among them, there was a strain producing the metal β-lactamase (VIM-2), characterized by absolute resistance to antibiotics of all classes, including carbapenems.
Conclusion. The findings on sensitivity profiles and molecular genetic mechanisms of resistance of Gram-negative uropathogens are unique for the Almaty region provides the rationale for developing a local strategy for rational antibiotic therapy. Timely microbiological diagnosis and strict adherence to infection control in a specific hospital are the only way to contain the spread of ESBL and metal β-lactamase.
Materials and methods. The study examined the etiological composition and antibiotic susceptibility of clinically significant isolates of bacteria and fungi (≥ 103) isolated from the urine of the patients of the Department of Urology of the Almaty city Central Clinical Hospital No. 12. The production of extended-spectrum beta-lactamases (ESBL) in antibiotic-resistant strains was determined using a phenotypic method with the double disk test. Detection of class A genes for cultures with confirmed ESBL phenotypes (TEM-1, CTX-M1, SHV, OXA) and carbapenemases of class B metallo-β-lactamases (VIM-2) genes was performed by PCR.
Results. Among the isolates obtained from patients, the species of Enterobacteriaceae family in the etiological composition of the UTI pathogens comprised 44.8% including E. coli (31%), K. pneumoniae (4.6%). The most effective drugs against all types of Enterobacteria were carbapenems (96.3-100%). E.coli showed highest sensitivity to nitrofurantoin (96.3%), amikacin (92.6%) and cefoxitin (81.5%). The high rate of resistance to III-IV generation cephalosporins among of E. coli (44.4%) and K. pneumoniae (50%) species was due to the production of ESBL types CTX-M1 and OXA. The proportion of non-fermenting Gram-negative bacteria in the etiological composition of UTI pathogens was 3.5%. Among them, there was a strain producing the metal β-lactamase (VIM-2), characterized by absolute resistance to antibiotics of all classes, including carbapenems.
Conclusion. The findings on sensitivity profiles and molecular genetic mechanisms of resistance of Gram-negative uropathogens are unique for the Almaty region provides the rationale for developing a local strategy for rational antibiotic therapy. Timely microbiological diagnosis and strict adherence to infection control in a specific hospital are the only way to contain the spread of ESBL and metal β-lactamase.
Keywords: urinary tract infections, gram-negative microorganisms, Enterobacteriaceae, antibiotic resistance, extended-spectrum β-lactamase, metal-β-lactamase
About the Autors
Corresponding author: A.L. Bissekenova – Md, PhD, docent of microbiology, virology and immunology department, Asfendiyarov Kazakh National Medical University, Almaty, Republic of Kazakhstan; e-mail: bissekenova_akma@mail.ru
