Seven-year active surveillance on carbapenemase-producing Klebsiella pneumoniae colonisation in subjects attending an Italian University hospital

Background: Carbapenem-resistantEnterobacteriaceae (CRE),especially Klebsiella pneumoniae, havespread globally and representa serious and growing threat to public health.Theaim of this study is theevaluation of the situation about the distribution of the phenotypes and genotypes of thecarbapenemase-producing (CP) Klebsiella pneumoniae strains circulating in the University-Hospital of Parma as a result of theapplication of theactive surveillance plan during thelast seven years. Materials/methods: A total of 34.043 rectal swabs from 22.944 high-risk patients (e.g. discharges from, or readmissions to,acutecarefacilities, long-term carefacilities and intensivecare units) from November 2011 to October 2018.Therectal swabs wereinoculated onto chromogenicagar and the bluecolonies referring to presumptive CRE weresubcultured on MacConkey agar with a carbapenem disk.Thecarbapenem nonsusceptible strains wereidentified by MALDI-TOF MS and, when K. pneumoniae was revealed, thestrains weresubmitted to CR confirmation by antimicrobial susceptibility testing and to phenotypical analysis by modified Hodgeand disk diffusion inhibition tests,and to genotypical characterization. Results: Carbapenem-resistant K. pneumoniae strains were detected in 1178 cases and the production of carbapenemase was revealed in 1150 cases (5%).With regard to the genes detected by the molecular genotyping assay,all types of carbapenemase genes were detected among theanalyzed samples.The KPC gene was predominant followed by the VIM target, while OXA-48 and NDM genes were morerarely observed. In about 1% of the CP K. pneumoniae strains none of thetargeted genes was revealed. Conclusions:Since 2013, the Centers for Disease Control and Prevention assigned the highest threat level to CRE and declared that CRE require urgent public health attention.The detailed data regarding a correlation between the CP K. pneumoniaecolonized subjects and thoseinfected in thesame period will beextensively presented. In our experience, theresults of theapplication of activesurveillance on high risk patient categories suggest to maintain the guard about this problem.