Prevalence of antibiotic resistance genes bla-CTX-M, bla-SHV, bla-TEM in enterobacteria strains isolated from perinatal center patients

Abstract

Relevance A common mechanism of resistance is the synthesis of enzymes that inactivate the antibiotic (AB). Since its discovery at the end of the 20th century, ESBLs have spread widely throughout the world. Representatives of this group of complex protein compounds have common properties of hydrolysis of ß-lactam antibiotics and differ from each other in amino acid sequence. The genetic determinants that determine their synthesis are the bla-CTX-M, bla-SHV, and bla-TEM genes. Aims. To assess the prevalence of bla-CTX-M, bla-SHV, bla-TEM genes in antibiotic-resistant strains of enterobacteria isolated from samples of patients of the perinatal center. Materials & Methods. We studied 135 strains of ESBL-producing enterobacteria isolated during microbiological monitoring from January 01, 2020 to December 31, 2021. Biological material (feces (92), blood (1), urine (5), cervical canal discharge (33), last (4)) came from patients of the perinatal center (43 women and 92 newborns), examined both for clinical indications and during local microbiological monitoring. Species identification of isolated microorganisms was carried out by bacteriological method, detection of antibiotic resistance genes was carried out using real-time PCR. Results. In 87 cases (64.4%), the studied genetic determinants of antibiotic resistance were successfully identified. Of the 26 studied strains of Klebsiella pneumonia, 24 (92.3%) were able to establish the determinants of resistance to AB, 50% of which are represented by bla-CTX-M. Out of 66 Escherichia coli, 59 (89.33%) had a genetic profile of antibiotic resistance, which was also dominated by bla-CTX-M (67.80%). However, in the Enterobacter cloacae group, it was possible to determine the presence of the studied genes only in 8.10% of cases. K. pneumoniae carrying three antibiotic resistance genes bla-CTX-M, bla-SHV, bla-TEM was isolated once from a sample of the cervical canal of a woman aged 27 years. E. coli strains carrying the CTX-M gene were isolated from 3 mother-child pairs out of 135 cases: in mothers – from the discharge of the cervical canal in the third trimester of pregnancy, in newborns – from feces in the first week of life, which can indicate possible transmission of an AB-resistant microorganism either in utero or through the birth canal. Conclusions. Thus, in the course of the study, determinants of antibiotic resistance of enterobacteria isolated from patients of the perinatal center were identified in 64.4% of cases. The dominant gene leading to the occurrence of AD among ESBL is the bla-CTX-M gene. The number of strains with an established genetic profile of resistance to AB is less among Enterobacter cloacae (p<0.001). In order to study the genetic profile in more detail and to identify the mechanisms for the formation of antibiotic resistance, it is necessary to expand the detection of observed genes