title: Detection of an IncA/C plasmid encoding VIM-4 and CMY-4 β-lactamases in Klebsiella oxytoca and Citrobacter koseri from an inpatient in a cardiac rehabilitation unit.
abstract: A 62-year-old patient was transferred to the cardiac rehabilitation unit of the I.R.C.C.S. Fondazione S. Maugeri after undergoing a heart transplantation at the Acute Care Hospital I.R.C.C.S. S. Matteo of Pavia. On 1 August 2013 and during hospitalization in the rehabilitation unit, Klebsiella oxytoca and Citrobacter koseri clinical isolates were simultaneously recovered from the patient's preputial swab. Both the K. oxytoca and C. koseri strains were carbapenem- resistant by MicroScan System (Beckman Coulter). Carbapenem-resistant K. pneumoniae had previously been reported in the same rehabilitation facility. The aim of the study was to identify the carbapenem resistance mechanisms among the enterobacterial species recovered. Phenotypic screening tests useful to detect the β-lactamases/carbapenemases were performed. Carbapenem MICs were obtained by Etest. AmpC and MBL encoding genes were identified by PCR and sequencing. Conjugation assays and plasmid characterization were performed. Both of the K. oxytoca and C. koseri isolates were multi drug resistant, showing resistance to amoxicillin-clavulanic acid, three generation cephalosporins, ertapenem (K. oxytoca MIC, >32 mg/L; C. koseri MIC, 4 mg/L), imipenem (K. oxytoca MIC, 4 mg/L; C. koseri MIC, 12 mg/L), thrimethoprim sulphamethoxazole and gentamicin. Susceptibility was retained to fluoroquinolones, colistin and tigecycline. Molecular characterization confirmed the co-presence of blaCMY-4 and blaVIM-4 determinants in a 150 Kb transferable plasmid of IncA/C group. This case is the first detection in Italy of the K. oxytoca and C. koseri clinical isolates co-producing the CMY-4 and VIM-4 enzymes.
authors.affiliation: Clinical-Surgical, Diagnostic and Pediatric Sciences Department, University of Pavia, Italy.
authors.forename: Mariasofia
authors.initials: M
authors.lastname: Caltagirone
authors.affiliation: Clinical-Surgical, Diagnostic and Pediatric Sciences Department, University of Pavia, Italy.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Bitar
authors.affiliation: Clinical-Surgical, Diagnostic and Pediatric Sciences Department, University of Pavia, Italy.
authors.forename: Aurora
authors.initials: A
authors.lastname: Piazza
authors.affiliation: Clinical-Surgical, Diagnostic and Pediatric Sciences Department, University of Pavia, Italy.
authors.forename: Melissa
authors.initials: M
authors.lastname: Spalla
authors.affiliation: Clinical-Surgical, Diagnostic and Pediatric Sciences Department, University of Pavia, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Nucleo
authors.affiliation: I.R.C.C.S. Fondazione Salvatore Maugeri, Pavia, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Navarra
authors.affiliation: Clinical-Surgical, Diagnostic and Pediatric Sciences Department, University of Pavia, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Migliavacca
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D041041:Citrobacter koseri / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D006760:Hospitalization; D006801:Humans; D007297:Inpatients; D007558:Italy; D007710:Klebsiella Infections / Q000382:microbiology*; D041121:Klebsiella oxytoca / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010957:Plasmids / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases
keywords: Cephalosporinases; Metallo-β-lactamases; Multi-drug resistant Enterobacteriaceae; Rehabilitation unit