Temporal pattern of Klebsiella pneumoniae carbapenemase (KPC) on surfaces of an intensive care unit of a large hospital

  • Maria De Giusti
  • Alessia Cottarelli
  • Angela Del Cimmuto
  • Annamaria Lombardi
  • Alessandra Giordano
  • Angelo Giuseppe Solimini
  • Lucia Marinelli
Keywords: Klebsiella pneumoniae, carbapenemase-producing Klebsiella pneumoniae, Intensive Care Unit, environmental contamination


Background: Carbapenem-resistant Enterobacteriaceae are an increasing cause of healthcare-associated infections worldwide.
Patients with infections caused by Klebsiella pneumoniae resistant to carbapenems (KPC) have significant increases in both allcause
mortality and 30-day mortality. The aims of this study was to investigate the prevalence of KPC on environmental samples
collected during and after an outbreak caused by KPC in an intensive care unit (ICU) of a teaching hospital.
Methods: Between 2010 and 2014 we conducted a total of 132 environmental monitoring campaigns from different critical
surface of ICU ward in a Teaching Hospital Policlinico Umberto I. Samples were collected on surfaces in patient rooms and health
care area. All samples were cultured and K. pneumoniae isolates were identified by standard microbiological techniques. The
presumptive colonies were confirmed and tested for antibiotic resistance by an automated system. K. pneumoniae resitant to
carbapenems were tested for carbapenemase production by modified Hodge test.
Results: A total of 2526 environmental samples were collected from November 2010 to July 2014. Of those, 111 resulted positive
for K. pneumoniae while KPC were 95 (85.6% of all K. pneumoniae, 3.8% of total samples). KPC was recovered in all patient
rooms with similar proportion (5.1-5.6%) with the exception of patient 6 bed room where it was lower (2.4%). The pathogen was
not recovered in rooms dedicated to healthcare personnel and doctors. Among surfaces, the highest proportion of KPC resulted on
bedrail (6.8%), more than double than other surfaces. Washbasins had nearly half of samples KPC positive (1.2%).
Conclusions: Despite previous studies suggested that environment plays a minor role in the transmission of carbapenem-resistant
enterobacteriaceae, our data highlighted that surfaces represents a significant reservoir for KPC possibly supporting transiently
contamination of hands of healthcare workers in our ICU. Our results confirm that KPC are more likely found on surfaces closer to
the patient than on those situated further away.