Carbapenem-resistant enterobacteriaceae: don’t trust your neighbour

Background The spread of carbapenem-resistant enterobacteriaceae (CRE) outbreaks consists not only of germs producing KPC and OXA-48, endemic already, but also metallo-beta-lactamase such as NDM or VIM. In Tuscany, Italy, a multidisciplinary regional task force has extended, since NDM alert spread out, from 1st Oct 2019 the CRE screening programme, via molecular testing, to newly admitted patients in high risk settings (medical, intensive care, oncology, transplant, infectious diseases, cardiac surgery units) to fight cross-contamination. The aim of the study is to assess levels and types of CRE in an italian teaching hospital (615 beds) after the programme became effective. Methods The surveillance team began recording daily all the CRE positive cases, defined as laboratory confirmed colonizations/infections with CRE. Our retrospective, descriptive study covers the time span between 30th Sep - 16th Dec 2019. Cases were classified by infected apparatus and by resistance phenotype, and we calculated descriptive statistics. Results In total we identified 97 cases (male 60.82%, mean (+/-SD) age 71.58+/-17.34 years, 74.23% in medical wards); 5 patients had two body districts infected and 9 carried two different phenotypes. Out of 102 positive samples, 92.16% were bowel colonization, 1.96% BSI, 3.92% urinary and 1.96% respiratory. Among these, 21 were NDM (19.81%), 29 KPC (27.36%), 4 OXA-48 (3.77%), 52 VIM (49.06%). The most detected germ was Klebsiella pneumoniae (30.19%), followed by Escherichia coli (2.83%), Enterobacter cloacae (2.83%), Citrobacter freundii and braakii (2.83%), Klebsiella oxytoca (1.89%). 61 agents were unspecified (57.55%). Among the 21 NDM, 76.19% were K. pneumoniae, only one was a BSI. Conclusions CREs continue to be present despite constant surveillance. Although high levels of KPC-producing agents persist, the new spread of VIM phenotype is significant, highlighting, however, that the pathogen wasn't detected in over 50% of the samples. Key messages Despite increased surveillance, there is still a consistent portion of patients colonized with unidentified CRE. A surveillance mainly focused on NDM-producing CREs had incidentally highlighted an unexpected spread of VIM phenotype.