ST405 NDM-5 producing Escherichia coli in Northern Italy: the first two clinical cases.

The spread of carbapenemases in Enterobacteriaceae represents a global menace, with nosocomial and community-acquired New Delhi metallo-b-lactamase (NDM) Escherichia coli now on the top list of metallo-b-lactamase (MBL) producers in Europe. Medical tourism, business travel, and world-wide diaspora have played a central role in establishing secondary reservoirs [1]. The early identification of pandemic lineages of extraintestinal pathogenic E. coli associated with multi-resistance plasmids is mandatory from a public health and clinical standpoint. In March 2015, an Italian man in his 60s reporting a history of vacation in Thailand during the winter of 2015 was admitted to the emergency room of the Civil Hospital “La Memoria” (AO Desenzano del Garda, Brescia) with an acute gallstone pancreatitis. Blood cultures obtained at the admission were negative for the presence of bacteria and fungi. The patient underwent surgery for cholecystectomywith biliary drainage andwas subjected to empiric therapy with piperacillin-tazobactam for 5 days. Three days after surgery, the patient was febrile, and a drain blood serum sample was positive for the presence of a NDM-E. coli strain (EcDT-1_GA) by Xpert Carba-R test (GeneExpert, Cepheid). The strain displayed highlevel-resistance to cephalosporins, carbapenems, fluoroquinolones, and aminoglycosides, retaining susceptibility only to fosfomycin, colistin, and tigecycline by Vitek2 System. Despite a later ascertained intestinal colonization by NDM-E. coli (EcDT-2_GA), the patient was discharged in good condition, without any further antibiotic therapy. In late 2015, an Italian woman in her 70s with a history of gallbladder heteroplasia underwent surgery at the Borgo Roma Hospital (Verona), where rectal carriage of carbapenemasepositive Klebsiella pneumoniae and E. coli was reported. Strains were not available for further investigation. In November 2015, the patient was transferred to the surgical and then palliative care wards of “La Memoria” Hospital, where septicaemia caused by blaNDM-E. coli (EcBA_GA), occurred. The patient died later the same year. The three clinical NDM-E. coli strains were sent to Pavia University for further characterization. Identification and antibiotic susceptibilities were confirmed using the Microscan Autoscan4 System (Beckman Coulter); MBL production was phenotypically investigated using ertapenem (ETP) and ETP plus dipicolinic acid (RoscoDiagnostica). ETP, meropenem (MER), imipenem (IPM), and amikacin (AK) Minimum Inhibitory Concentrations (MICs) were