Extended-Spectrum β-Lactamases in the 21st Century: Characterization, Epidemiology, and Detection of This Important Resistance Threat

Abstract

SUMMARY β-Lactamases continue to be the leading cause of resistance to β-lactam antibiotics among gram-negative bacteria. In recent years there has been an increased incidence and prevalence of extended-spectrum β-lactamases (ESBLs), enzymes that hydrolyze and cause resistance to oxyimino-cephalosporins and aztreonam. The majority of ESBLs are derived from the widespread broad-spectrum β-lactamases TEM-1 and SHV-1. There are also new families of ESBLs, including the CTX-M and OXA-type enzymes as well as novel, unrelated β-lactamases. Several different methods for the detection of ESBLs in clinical isolates have been suggested. While each of the tests has merit, none of the tests is able to detect all of the ESBLs encountered. ESBLs have become widespread throughout the world and are now found in a significant percentage of Escherichia coli and Klebsiella pneumoniae strains in certain countries. They have also been found in other Enterobacteriaceae strains and Pseudomonas aeruginosa. Strains expressing these β-lactamases will present a host of therapeutic challenges as we head into the 21st century.

RETRACTED ARTICLE: Extended-spectrum β-lactamase producing Klebsiella pneumoniae in neonatal intensive care unit

“…Identical K. pneumoniae outbreak clones were isolated from infected neonates and HCWs' hands in NICUs. 6,7,9 Hand washing is a simple, low-cost, low-technology intervention and is considered to be the single most important factor in the prevention of nosocomial infections. 7 The introduction of alcohol-based hand rubs may have had a positive effect on reducing colonization and nosocomial infection rates, and their use is highly recommended.…”

“…Mutations in the genes encoding the TEM and SHV b-lactamases can extend the spectrum of enzyme activity to include penicillins, the extended-spectrum cephalosporins (for example, ceftazidime, cefotaxime and ceftriaxone) and aztreonam. 9 The emergence of ESBLs creates a real challenge for both microbiologists and clinicians because the dynamic evolution of ESBLs requires tedious efforts to keep the medical community updated with characterization and epidemiology of these organisms. In addition, ESBLs make bacteria potent and resistant against a wide range of antibiotics that have tremendous therapeutic implications.…”

Diversity of genotypes in CTX-M-producing Klebsiella pneumoniae isolated in different hospitals in Brazil

“…2 Various types of ESBL have been described worldwide. 3 In particular, CTX-M-type ESBLs have become the prevailing non-TEM, non-SHV ESBL among Enterobacteriaceae and is recognized as a rapidly growing family of ESBLs that preferentially hydrolyze cefotaxime rather than ceftazidime. 2,4,5 In recent studies, high rates of CTX-M enzymes among ESBL-producing K. pneu-pulmonary secretion (n = 5), catheter (n = 5), and other sites (n = 25).…”

Charakterisierung der extended spectrum b-Lactamasen (ESBL) und Bestimmung der von Kindern isolierten uropathogenen Virulenzfaktoren von Escherichia coli (E. coli) Stämmen

“…Production of ESBLs is the major mechanism of resistance to oxyminocephalosporins and aztreonam in Gram-negative bacteria [1][2]. ESBLs are predominantly derivatives of plasmid-mediated TEM or SHV β-lactamases and arise through mutations that alter the configuration of the active site, thereby expanding the hydrolytic spectrum of the enzyme [2].…”