Antimicrobial Use and Resistance Among Gram-negative Bacilli in an Italian Intensive Care Unit (ICU)

• Published in: Journal of chemotherapy (Florence) Vol. 18; no. 3; pp. 261 - 267
• Main Authors: Bassetti, M., Cruciani, M., Righi, E., Rebesco, B., Fasce, R., Costa, A., Molinari, M.P., Mengoli, C., Bobbio Pallavicini, F., Viscoli, C.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01-06-2006
• Subjects: Anti-Bacterial Agents - therapeutic use; Antimicrobial use; Cross Infection - drug therapy; Cross Infection - microbiology; Demography; Drug Resistance, Multiple, Bacterial; Drug Utilization; ESBL; Gram-negative bacteria; Gram-Negative Bacterial Infections - drug therapy; Gram-Negative Bacterial Infections - microbiology; Humans; ICU; Intensive Care Units; Italy - epidemiology; Length of Stay; Microbial Sensitivity Tests; Middle Aged; resistance; Retrospective Studies; Italy
• ISSN: 1120-009X; 1973-9478
• DOI: 10.1179/joc.2006.18.3.261

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, 3
rd
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.