Extended-Spectrum β-Lactamase–Producing Enterobacteriaceae in Bulgarian Hospitals

Abstract

The aim of the study was to describe the emergence, the spread, and the prevalence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in Bulgaria. Over eight years (1996-2003), 442 ESBL-screen-positive isolates were collected in nine medical institutions in four Bulgarian towns. Class A ESBLs of the SHV, TEM, and CTX-M groups were identified in seven species. SHV-type enzymes persisted during the whole study period, TEM-ESBLs appeared first in 1999, and CTX-M-types appeared first in 2001. The rate of CTX-M enzyme producers increased rapidly between 2001 and 2003, while the rate of SHV producers decreased. Six different ESBL-types were identified, namely, SHV-2, -5, and -12, CTX-M-3 and -15, and a new TEM-3-like variant (TEM-139). The most widespread enzymes were SHV-12, CTX-M-15, and CTX-M-3 found in seven centers. TEM-139 was identified mainly in one center. A trend for strains harboring more than one ESBL gene, for example, CTX-M + SHV, was observed since 2002. Plasmid fingerprinting and random amplified polymorphic DNA analysis typing revealed wide dissemination of identical plasmids among different bacterial species and hospitals, as well as clonal spread of ESBL producers. Our data contribute to clarify the dynamics in the prevalence of ESBLs in Bulgaria and demonstrate the importance of molecular procedures for their analysis.

Molecular characterization of bacteremic Escherichia coli isolates in Romania

“…β-lactamase gene identification PCR assays followed by sequencing of the amplicons were carried out to identify bla CTX-M , bla TEM , and bla SHV alleles (Markovska et al 2008). In this study, all the DNA sequencing reactions were performed with BigDye Terminator v3.1 Cycler Sequencing Kit (Applied Biosystems, Foster City, CA, USA) and analysed on an ABI 3130 Genetic Analyzer (Applied Biosystems, Foster City, CA, USA).…”

CTX-M-15 Type β-lactamases From Clinical Isolates of Escherichia coli by Polymerase Chain Reaction and DNA Sequencing

“…One of the major causes of resistance in Enterobacteriaceae corresponds to resistance to broad-spectrum β-lactams, which is mainly associated with production of extendedspectrum β-lactamases (ESBLs) [1]. ESBLs are able to hydrolyze a broad spectrum of β-lactam antibiotics and their hydrolytic activity can be inhibited by several β-lactamase inhibitors such as clavulanic acid and tazobactam [1][2][3].…”

Extended Spectrum Beta-lactamases: Definition, Classification and Epidemiology

“…The frequency of the occurrence of ESBL positive strains was more than 10% in Eastern Europe countries such as Hungary, Poland, Romania, Russia and Turkey. In all the mentioned countries, K. pneumoniae was found to be dominant ESBL positive (Damjanova et al, 2007;Korten et al, 2007;Markovska et al, 2008 ). The enzymes mostly responsible for ESBL production in Eastern Europe countries are: CTX-M-3, SHV-2 and SHV-5.…”