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NDM-type metallo-β-lactamase (MBL)-producing Enterobacterales remain uncommon in the European region, especially among species other than Klebsiella pneumoniae and Escherichia coli. The aim of this study was to describe epidemiological and molecular characteristics of a widespread NDM-1-producing Enterobacter cloacae complex outbreak in Greece. Over a 6-year period (March 2016-March 2022), a retrospective study was conducted in a tertiary care Greek hospital. Ninety single-patient carbapenem-non-susceptible E. cloacae complex clinical isolates were recovered consecutively. The isolates were subjected to further investigation, including antimicrobial susceptibility testing and combined disc tests for carbapenemase production, polymerase chain reaction and sequencing for resistance genes, molecular fingerprinting by pulsed-field gel electrophoresis (PFGE), plasmid profiling, replicon typing, conjugation experiments, genotyping by multi-locus sequence typing (MLST), whole-genome sequencing and phylogenetic analysis. Phenotypic and molecular testing confirmed the presence of bla NDM-1 in 47 (52.2%) of the E. cloacae complex isolates. MLST analysis clustered all but four of the NDM-1 producers into a single MLST sequence type (ST182), whereas single isolates belonged to different sequence types (ST190, ST269, ST443 and ST743). PFGE analysis revealed that ST182 isolates were clustered into a single clonal type, with three subtypes, which differed from the clonal types detected among the remaining carbapenem non-susceptible E. cloacae complex isolates identified during the study period. All ST182 bla NDM-1 -carrying isolates also harboured the bla ACT-16 AmpC gene, while the bla ESBL , bla OXA-1 and bla TEM-1 genes were detected in most cases. In all clonal isolates, the bla NDM-1 gene was located on an IncA/C-type plasmid, and flanked upstream by an ISAba125 element and downstream by ble MBL . Conjugation experiments failed to produce carbapenem-resistant transconjugants, indicating a low dynamic for horizontal gene transfer. Application of enforced infection control measures led to the absence of new NDM-positive cases for periods of time during the survey. This study represents the largest clonal outbreak of NDM-producing E. cloacae complex in Europe., (Copyright © 2023 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.)

Carbapenem-resistant Enterobacterales have become a major public-health issue worldwide. Here we report an outbreak caused by a clonal multidrug-resistant Proteus mirabilis strain producing VIM-4 metallo-β-lactamase (MBL) and TEM-2 β-lactamase in a Greek tertiary-care hospital. From July 2015 to February 2016, 27 imipenem-resistant P. mirabilis isolates were recovered from 14 patients hospitalised in two intensive care units (ICUs) and the internal medicine department in AHEPA University Hospital, Thessaloniki. The isolates were either susceptible or resistant to meropenem and were resistant to all remaining β-lactams except aztreonam. Phenotypic and molecular analysis revealed that all of the isolates harboured a bla VIM-4 MBL gene. Resistome analysis of a representative isolate showed the presence of an IncQ1 plasmid harbouring the bla VIM-4 carbapenemase and bla TEM-2 β-lactamase genes among resistance genes coding for resistance to β-lactams, aminoglycosides, trimethoprim, sulfonamides and lincosamides. Genotyping by pulsed-field electrophoresis (PFGE) revealed that the isolates were epidemiologically related. After recovery of the index carbapenemase-producing P. mirabilis clinical isolate, infection control measures were intensified in the affected departments. Rectal sampling for carbapenem-resistant bacteria was initiated on a weekly basis among patients admitted to the general ICU. The outbreak was finally interrupted 6 months later in February 2016. This is the first documentation of the bla VIM-4 MBL gene in P. mirabilis as well as the first hospital outbreak caused by a MBL-producing P. mirabilis strain., Competing Interests: Declaration of Competing Interest None declared., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Here we present the characteristics of a large outbreak caused by a clonal Klebsiella pneumoniae strain producing both KPC-2 and VIM-1 carbapenemases in a tertiary teaching hospital. Between January 2013 and January 2015, 45 carbapenem-resistant K. pneumoniae isolates that gave a positive modified Hodge test and were phenotypically suspected of metallo-β-lactamase (MBL) and K. pneumoniae carbapenemase (KPC) co-production were recovered from 25 patients hospitalised in AHEPA University Hospital (Thessaloniki, Greece). All of the patients were hospitalised in the three intensive care units of the hospital and 17 (68%) of them developed bloodstream infections; the overall mortality of the patients involved in the outbreak was 48% (12/25). Molecular testing verified that all 45 K. pneumoniae isolates co-harboured bla KPC-2 and bla VIM-1 genes and were associated with OmpK35 deficiency and OmpK36 porin loss. The bla TEM-1 gene was also present in 18 isolates. Pulsed-field gel electrophoresis (PFGE) clustered all of the isolates into a single clonal type, and multilocus sequence typing (MLST) assigned them to the emerging high-risk ST147 clonal lineage. Following recognition of the outbreak, infection control measures were implemented in the affected areas. The outbreak continued for ca. 2 years and since then only sporadic cases of K. pneumoniae harbouring both carbapenemases have been detected., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Information on the drug susceptibility of influenza epidemic strains is important for antiviral resistance monitoring. In Greece, the 2009-2010 pandemic waves were very mild and seroprevalence rates remained low after this influenza season, resulting in exclusive detection of the pandemic strain during the 2010-2011 influenza season. In the present study during the post-pandemic 2010-2011 season, 50 consecutive influenza A(H1N1) 2009 virus-positive samples from patients hospitalised in Greek hospitals were analysed for resistance to the neuraminidase inhibitor oseltamivir. All patients were hospitalised with severe influenza complications and had previously received oseltamivir. Influenza A(H1N1) 2009 virus detection and testing for oseltamivir resistance were performed with real-time PCR amplification assays. The H275Y substitution associated with resistance to oseltamivir was identified in two immunocompetent patients who received oseltamivir treatment for 3 days and 5 days, respectively. In both cases, patients were discharged in good condition despite development of resistance to antiviral treatment., (Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.)