title: Extended-spectrum beta-lactamases in urinary tract infections caused by Enterobacteria: understanding and guidelines for action.
abstract: BACKGROUND
  Beta-lactamases are bacterial enzymes that protect microorganisms from the lethal effects of β-lactam antibiotics. The production of beta-lactamases is the most important mechanism of resistance to these antibiotics, especially in Gram-negative bacteria.
  
  
  OBJECTIVE
  Review the magnitude of the problem of extended-spectrum beta-lactamases (ESBL) in the urological setting and present the fundamental action guidelines on the issue, the main risk factors and the prevention strategies.
  
  
  METHODS
  A structured search strategy for patient, problem, intervention, comparison and result was conducted in the PubMed-Medline database to identify the most relevant studies related to the management of patients with urinary tract infection by ESBL-producing microorganisms. We also present a caseload analysis of our center on this issue.
  ESBL are found in Enterobacteria, mainly Klebsiella sp. and Escherichia coli and are characterized by their hydrolytic ability compared with beta-lactam antibiotics, which entails resistance to penicillin, cephalosporin and aztreonam. They are also associated with resistance to other antibiotics. There is a high risk of infection and colonization by ESBL producers in patients with prolonged hospital stays or who required invasive devices. The prior use of antibiotics and stays in residential care are also risk factors. Prevention programs should focus on preventing nosocomial infection. It is essential that a restrictive policy on the use of antibiotics be implemented. The therapy of choice for severe infections is focused on carbapenems, although their indiscriminate use should be avoided. In uncomplicated lower urinary tract infections, fosfomycin and nitrofurantoin are the best treatment alternatives.
  
  
  CONCLUSIONS
  ESBL-producing strains constitute a true global health problem. Prevention strategies should focus on nosocomial infection. We should not forget, however, that the appearance of these pathogens in community-acquired infections is increasingly frequent. Therapeutic decisions should be based on an understanding of the local distribution of microorganisms and their resistance patterns.
authors.affiliation: Servicio de Urología, Hospital Universitario de Getafe, Departamento Clínico, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, España. Electronic address: anagtello@yahoo.es.
authors.forename: A
authors.initials: A
authors.lastname: García-Tello
authors.affiliation: Servicio de Urología, Hospital Universitario de Getafe, Departamento Clínico, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, España.
authors.forename: H
authors.initials: H
authors.lastname: Gimbernat
authors.affiliation: Servicio de Urología, Hospital Universitario de Getafe, Departamento Clínico, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, España.
authors.forename: C
authors.initials: C
authors.lastname: Redondo
authors.affiliation: Servicio de Microbiología, Hospital Universitario de Getafe, Departamento Clínico, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, España.
authors.forename: D M
authors.initials: DM
authors.lastname: Arana
authors.affiliation: Servicio de Microbiología, Hospital Universitario de Getafe, Departamento Clínico, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, España.
authors.forename: J
authors.initials: J
authors.lastname: Cacho
authors.affiliation: Servicio de Urología, Hospital Universitario de Getafe, Departamento Clínico, Facultad de Ciencias Biomédicas, Universidad Europea de Madrid, Madrid, España.
authors.forename: J C
authors.initials: JC
authors.lastname: Angulo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003428:Cross Infection; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology; D004756:Enterobacteriaceae Infections / Q000188:drug therapy*; D006801:Humans; D017410:Practice Guidelines as Topic; D014552:Urinary Tract Infections / Q000188:drug therapy*; D001618:beta-Lactamases
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases
keywords: Antibiotic resistance; Betalactamasas de espectro extendido; Carbapenems; Carbapenémicos; Extended-spectrum beta-lactamases; Infección del tracto urinario; Resistencia antibiótica; Urinary tract infection