Sorveglianza di microrganismi “sentinella” all’Ospedale di Desio (MI) negli anni 2000-2005

Introduction: Antimicrobial resistance among nosocomial pathogens is steadily increasing, causing complications to patients and raising health care costs.To prevent the diffusion of antimicrobial-resistant organisms, a surveillance program was conducted at Desio Hospital.The aim of this work was to evaluate the prevalence of alert organisms in patients from Seregno and Desio Hospitals. Methods: Among alert organisms collected from 2000 to 2005, we considered: methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile toxigenic (CD-tox), vancomycin-resistant Enterococci (VRE), pathogens producing Extended-Spectrum β-Lactamases (ESBLs).The prevalence was calculated as percentage of alert organisms on positive samples; CD-tox percentage is referred to all the samples collected. Rates for thousand inpatients were also calculated. Results: During the period 2000 to 2005 the prevalence of MRSA decreased from 61.3% to 44.9% (Pfortrend<0.001).The rate/1000 of CD-tox increased from 0.6 to 3.5, although the prevalence fell from 23.1% to 17.8% (Pfortrend=0.003), owing to the growing number of requests.The prevalence of VRE decreased from 8.2% in 2003 to 2.3% in 2004 (not statistically significant).The prevalence of ESBLs increased from 3.8% in 2000 to 6.6% in 2005 (Pfortrend=0.025). Conclusions: The surveillance program conducted at Desio Hospital may have contributed in decreasing the number of MRSA,VRE and CD-tox isolates.The great increase in the frequency of ESBLs isolates is attested in different studies.