title: Unusual genetic heterogeneity of Acinetobacter baumannii isolates in a university hospital in Italy.
abstract: BACKGROUND
  Acinetobacter baumannii has become an increasingly important nosocomial pathogen, particularly in intensive care units (ICUs). The aim of this investigation was to study the molecular epidemiology of A baumanii in a university hospital in Italy.
  
  
  METHODS
  All A baumanii isolates were collected and typed with phenotypic and genotypic methods during a 7-month period. A 1-year prospective surveillance of ICU-acquired infections was performed by using the National Nosocomial Infections Surveillance methodology.
  
  
  RESULTS
  A baumanni accounted for 28.4% of all infections and 46.7% of all pneumonia acquired in the ICU, with a nosocomial infection rate of 12.4% or 8 infections per 1000 patient-days. Risk factors for A baumannii acquisition in the ICU were mechanical ventilation and previous use of broad-spectrum antibiotics, whereas administration of carbapenems showed a significant protective effect. Pulsed-field gel electrophoresis of genomic Apa I digests identified at least 5 outbreaks in the ICU caused by 5 different clones, one replacing the other in a well-defined temporal order.
  
  
  CONCLUSIONS
  Whereas the sequential temporal cluster of epidemic clones in the ICU is intriguing and requires further research, the clear evidence of cross-contamination of A baumannii isolates involved with infections in the ICU demands extensive preventive efforts.
authors.affiliation: Institute of Hygiene and Preventive Medicine, University "Federico II,", Naples, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Villari
authors.forename: L
authors.initials: L
authors.lastname: Iacuzio
authors.forename: E A
authors.initials: EA
authors.lastname: Vozzella
authors.forename: U
authors.initials: U
authors.lastname: Bosco
mesh_terms: D000150:Acinetobacter / Q000235:genetics* / Q000302:isolation & purification; D000151:Acinetobacter Infections / Q000145:classification / Q000453:epidemiology / Q000382:microbiology* / Q000401:mortality; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D007558:Italy / Q000453:epidemiology; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010641:Phenotype; D012307:Risk Factors