CHARACTERISTIC OF ANTIBIOTIC-RESISTANT STRAINS OF GRAM-NEGATIVE BACTERIA ISOLATED FROM PATIENTS OF THE PURULENT SURGERY DEPARTMENTS

Abstract

Resume. This article presents the etiological structure and the results of the evaluation of antibiotic susceptibility of strains of gram-negative bacteria isolated from patients of the purulent surgery departments. In the etiologic structure of purulent infections, gram-negative bacteria collectively take a leading role (57,8%, n=128). The overall percentage of members of the Enterobacteriaceae family was 33.6%, PGOB - 21.1%. The predominant species were E. coli, K. pneumoniae, P. aeruginosa and A. baumannii.

The most active drugs against E. coli were carbapenems and amikacin (91.7 - 100% and 75,0% of sensitive strains, respectively); 42,7 - 62.5% of strains were sensitive to tobramycin and gentamicin. Resistance of III – IV generations of E. coli to cephalosporins in 54,2% of cases were due to production of beta-lactamase extended spectrum (ESBL) TEM1, CTX – M1 and OXA types.

K. pneumoniae was totally resistant (100%) to all groups of the studied antibiotics, except carbapenems and amikacin. 40% of strains were sensitive to ertapenem, 20% to meropenem and 40% to amikacin. During PCR detection, 60% of the K. pneumoniae isolates were producers of blaTEM1 and blaOXA.

Carbapenems showed high activity against isolated strains of P. aeruginosa: imipenem (87,5%), meropenem (75%); of the aminoglycoside - amikacin (75% of strains were sensitive); of the quinolones – levofloxacin (50%). 25% of strains resistant to cephalosporins of III-IV generations carried ТЕМ1 genes responsible for the ESBL production of molecular class A. A nosocomial P. aeruginosa strain was registered, that is absolutely resistant to all groups of antibiotics that carries the gene MBL VIM-2.

All A. baumannii strains were completely resistant (100%) to all groups of the studied antibiotics, except carbapenems and tobramycin (from 55.6 – 66.7% and 77,8% of sensitive strains). Along with insensitivity to cephalosporins of III – IV generations, 3 isolates of A. baumannii (genotypic detection of which, found genes of acquired carbapenemase class D (OXA-23) showed resistance to carbapenems (Meropenem and imipenem). 2 isolates carried genes ТЕМ1 responsible for the production of ESBL molecular class A.