ESBL-Producing Escherichia coli Isolated from Bloodstream Infections – Antimicrobial Susceptibility, Conjugative Transfer of Resistance Genes and Phylogenetic Origin

Abstract

Background. The prevalence of bloodstream infections (BSIs) due to ESBL-producing Escherichia coli (ESBL-EC) strains has increased dramatically over the past years. Objectives. Characterization of ESBL-EC isolates collected from BSIs with regard to their antimicrobial susceptibility and phylogenetic background. The conjugative transfer of resistance determinants to the E. coli reference strain K12 C600 was also investigated. Material and Methods. A collection of forty-eight ESBL-EC strains recovered from BSIs was subjected to the study. These strains were obtained from the ICU (intensive care unit) of the Medical University Hospital, Wrocław, Poland, during a four-year period (2009)(2010)(2011)(2012). All the isolates were screened for ESBL production by the double disk synergy test (DDST). Transferability of plasmid-mediated resistance genes was performed by the conjugational broth method. Susceptibility to antibiotics and chemotherapeutics of clinical isolates and transconjugants was determined by the agar dilution method. PCR assay was used to detect the bla CTX-M gene in ESBL-EC tested and transconjugants. Affiliation to phylogenetic groups was done by the triplex PCR method. Results. Conjugational transfer of plasmids responsible for ESBL to a recipient strain was successful for all the ESBL-EC analyzed (donors). The conjugation frequencies ranging from 2.3 × 10 -7 to 5.2 × 10 -1 per donor. In vitro susceptibility testing revealed that all the ESBL-EC isolates and their transconjugants were resistant to most of the antimicrobial agents tested with the exception of carbapenems, tigecycline, and β-lactam-clavulanate combinations. Moreover, all the donor strains and their transconjugants were found to contain the bla CTX-M gene. The majority of the isolates analyzed belonged to phylogroups B2 (62.5%) and D (25%), whereas groups B1 and A were less frequently represented (8.3% and 4.2%, respectively). Conclusions. The results of the study confirm the need of antibiotic policies and effective infection control measures in hospital settings to minimize BSIs caused by multi-resistant ESBL-producing pathogens (Adv Clin Exp Med 2014, 23, 6, 865-870).

Antibiotic Susceptibility Profile of Escherichia coli and Salmonella Causing Childhood Diarrhoea in Awka Municipality, South-eastern Nigeria

“…In the present study, out of 23 E. coli, 65.2% (15/23) were ESBL producers by phenotypic confirmatory methods. In line with our finding, a similar high ESBL-producing was recorded of Escherichia coli isolated from Children with Acute Diarrhoea in Wrocław, Poland [31]. The high prevalence of ESBL-producing among the E. coli isolates is a big concern as they might show a false sensitive zone of inhibition in the Kirby-Bauer disk diffusion method and often remain undetected by routine susceptibility tests [26,32].…”

“…ESBL producers may have spared through communities, especially those with poor hygienic and sanitation conditions, through faecal contamination of soil and water, since most patients with ESBL producers may have had their gastrointestinal tracts colonized by these organisms [34]. β-lactamase production is perhaps the most reported important mechanism of resistance to penicillin and cephalosporins and E. coli is known to possess a naturally occurring chromosomally mediated and/or plasmid-mediated β-lactamases [17,31].…”

Do bacteria isolated from ICU patients ‘ESKAPE’ antibiotic treatment? In vitro susceptibility of the Enterobacteriaceae family to tigecycline

“…Tigecycline seems to be used in infections caused by many MDR strains, for example ESBL-positive phenotype strains [3,6,14]. In our study, tigecycline demonstrated the highest in vitro sensitivity to K. pneumoniae, even to ESBL+ and E. coli strains, a phenomenon which is confirmed by other authors [16,[18][19][20]. For E. cloacae, other authors have shown the high in vitro activity of tigecycline [19], which was an opposite result to the one in our study.…”

Molecular and phenotypic typing of enteropathogenic Escherichia coli isolated in childhood acute diarrhea in Abuja, Nigeria

“…EPEC strains encoding for ESBLs isolated from children have widely been reported in various parts of the world [56][57][58][59]. Nevertheless, no ESBL-producing EPEC strain was detected in this study.…”