title: Epidemiology and genetic characteristics of extended-spectrum β-lactamase-producing Gram-negative bacteria causing urinary tract infections in long-term care facilities.
abstract: OBJECTIVE
  To assess risk factors for acquiring extended-spectrum β-lactamase-producing Gram-negative bacteria (ESBL+ GN) causing urinary tract infections (UTIs) in long-term care facilities (LTCFs).
  
  
  METHODS
  A prospective case-case-control study was carried out. In the first study, cases were defined as patients harbouring ESBL+ GN, while, in the second study, cases were defined as patients harbouring ESBL-negative (ESBL-) GN. Controls were selected by simple random sampling from patients without GN infection. ESBL determinants were characterized by hybridization, and confirmed by PCR and sequencing.
  
  
  RESULTS
  The study involved 297 LTCF patients (99 with ESBL+ GN UTI, 99 with ESBL- GN UTI and 99 without GN infection). ESBL+ GN UTIs were due to Escherichia coli (64%), Proteus mirabilis (25%) and Klebsiella pneumoniae (11%). The CTX-M-type enzymes were the most prevalent (73% of isolates), whereas TEM- and SHV-type ESBLs and AmpC-type enzymes were less prevalent (10%, 2% and 15% of isolates, respectively). Patients with ESBL+ GN UTI were more likely to have a permanent urinary catheter (OR 15, 95% CI 6.9-30.5) and to have received antimicrobial therapy in the previous 30 days (OR 4, 95% CI 1.2-10.9). After adjusting for type, dosage and duration of antibiotic, exposure to ≥7 days of quinolones and third-generation cephalosporins was associated with the highest risk of ESBL+ GN UTI development (OR 7, 95% CI 1.2-40). Independent risk factors for acquiring ESBL- GN UTIs were previous surgical procedures (OR 2, 95% CI 1.1-4) and the presence of a urinary catheter (OR 8, 95% CI 4-16). No specific antibiotics remained a significant risk for ESBL- GN UTI after adjusting for demographic and clinical risk factors.
  
  
  CONCLUSIONS
  Exposure to ≥7 days of quinolones and third-generation cephalosporins significantly increases the risk of ESBL+ GN UTI. Interventions aimed at improving compliance with antimicrobial stewardship principles should be further developed and implemented in LTCFs.
authors.affiliation: Division of Infectious and Tropical Diseases,  Hospital of Lodi, Lodi,  Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Tinelli
authors.forename: Maria Adriana
authors.initials: MA
authors.lastname: Cataldo
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Mantengoli
authors.forename: Chiara
authors.initials: C
authors.lastname: Cadeddu
authors.forename: Ettore
authors.initials: E
authors.lastname: Cunietti
authors.forename: Francesco
authors.initials: F
authors.lastname: Luzzaro
authors.forename: Gian Maria
authors.initials: GM
authors.lastname: Rossolini
authors.forename: Evelina
authors.initials: E
authors.lastname: Tacconelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005260:Female; D005838:Genotype; D006090:Gram-Negative Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008134:Long-Term Care; D008297:Male; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D014552:Urinary Tract Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D001618:beta-Lactamases