title: Molecular epidemiology of KPC-producing Klebsiella pneumoniae from invasive infections in Italy: increasing diversity with predominance of the ST512 clade II sublineage.
abstract: The spread of carbapenem-resistant Enterobacteriaceae (CRE) represents one of the most worrisome problems for clinical medicine worldwide. In Italy, the Antibiotic-Resistance-Istituto Superiore di Sanità surveillance network, in collaboration with the Committee for Antimicrobial Agents of the Italian Society of Clinical Microbiologists, promoted a study to investigate the carbapenem-resistance mechanisms, clonal relatedness and capsular typing of a recent collection of carbapenem-resistant Klebsiella pneumoniae (CR-KP).
  
  
  
  A total of 17 laboratories distributed across Italy collected all consecutive non-replicate CR-KP isolated from invasive infections during two different study periods (2011-12 and 2013). Carbapenemase genes were searched for by filter hybridization and confirmed by PCR and sequencing. KPC-producing K. pneumoniae (KPC-KP) were typed by PFGE and MLST. Capsular types were identified by wzi gene typing.
  
  
  
  Of the collected K. pneumoniae isolates (n = 461), the overall proportion of CR-KP was 36.2% (n = 167). The majority (97%) of the CR-KP were positive for the blaKPCgene. Among the KPC-KP population, nine different STs were detected with the majority of isolates (94%) belonging to the clonal group (CG) 258. A subpopulation that belonged to ST512 and showed an identical PFGE profile represented the majority (57%) of KPC-KP strains, with a countrywide distribution. Capsular characterization showed the predominance of the wzi154, cps-2 capsular type (88.8% of all CG258 strains). ST258 strains were associated with both cps-1 and cps-2 capsular types, while ST512 was associated with cps-2 only.
  
  
  
  Although a trend to a polyclonal evolution of the Italian KPC-KP was noted, this study showed that the KPC-KP population remained largely oligoclonal with the wide diffusion of an ST512 lineage carrying cps-2 capsular type and producing the KPC-3 enzyme.
authors: Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors: Viola
authors: V
authors: Conte
authors: Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors: Monica
authors: M
authors: Monaco
authors: Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors: Tommaso
authors: T
authors: Giani
authors: National Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Rome, Italy.
authors: Fortunato
authors: F
authors: D'Ancona
authors: Infectious Risk Area, Agenzia Sanitaria e Sociale Regionale Emilia-Romagna, Bologna, Italy.
authors: Maria Luisa
authors: ML
authors: Moro
authors: Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors: Fabio
authors: F
authors: Arena
authors: Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors: Marco Maria
authors: MM
authors: D'Andrea
authors: Department of Medical Biotechnologies, University of Siena, Siena, Italy gianmaria.rossolini@unifi.it.|Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.|Clinical Microbiology and Virology and Serology Unit, Florence Careggi University Hospital, Florence, Italy.|Don Carlo Gnocchi Foundation, Florence, Italy.
authors: Gian Maria
authors: GM
authors: Rossolini
authors: Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors: Annalisa
authors: A
authors: Pantosti
mesh_terms: D003430:Cross-Sectional Studies; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007558:Italy / Q000453:epidemiology; D007710:Klebsiella Infections / Q000453:epidemiology* / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D065288:Serogroup; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases