Antimicrobial use and resistance among gram-negative bacilli in an Italian Intensive Care Unit (ICU)

Matteo Bassetti, M. Cruciani, E. Righi, B. Rebesco, R. Fasce, A. Costa, M. P. Molinari, C. Mengoli, F. Bobbio Pallavicini, C. Viscoli

Research output: Contribution to journalArticlepeer-review


Gram-negative bacilli antimicrobial resistance remains a significant problem for patients in the intensive care unit (ICU). We performed a retrospective analysis of microbiological data and antibiotic consumption over a 4-year period (2000-2003) in an Italian ICU. Pseudomonas aeruginosa and Klebsiella pneumoniae represented approximately 40% of all isolates. The most significant trend in antimicrobial use was an increase in use of 3rd generation cephalosporins, imipenem, and ciprofloxacin. A significant trend toward an increase in resistance rates to piperacillin, 3rd generation cephalosporins and ciprofloxacin was observed for K. pneumoniae and a positive correlation between resistance and drug-usage was evident for K. pneumoniae and piperacillin, cefotaxime, ceftazidime, cefepime, and ciprofloxacin, but not for piperacillin/tazobactam. No statistically significant correlations were evidenced for P. aeruginosa. Trends in resistances were studied also for Serratia spp and Proteus spp. Isolation rates of extended-spectrum beta-lactamase (ESBL)-producing strains in pathogens studied were high, especially for K. pneumoniae (72%, 160/222) and Proteus spp (41%, 18/43). In conclusion, the study showed high resistance among Gram-negative organisms isolated in the ICU and significant ESBL production. A significant correlation between antibiotic consumption and increasing resistance was evident for K. pneumoniae.

Original languageEnglish
Pages (from-to)261-267
Number of pages7
JournalJournal of Chemotherapy
Issue number3
Publication statusPublished - Jun 2006


  • Antimicrobial use
  • ESBL
  • Gram-negative bacteria
  • ICU
  • Resistance

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Microbiology (medical)


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