Short communication In vivo transmission of a plasmid containing the KPC-2 gene in a single patient § Irene Galani, Theofano Panagea, Zoi Chryssouli, Helen Giamarellou *, Maria Souli 4th Department of Internal Medicine, Athens University School of Medicine, University General Hospital ‘Attikon’, 1 Rimini Street, 124 62 Chaidari, Athens, Greece 1. Introduction The global spread of carbapenem-resistant Enterobacteriaceae is increasingly recognized as an emerging threat to public health. The most epidemiologically important among them is Klebsiella pneumoniae producing a KPC-type b-lactamase, which was first described in 1996 in North Carolina, USA, but has now spread worldwide [1]. Genetic analysis of bla KPC genes indicates that their mobility may be associated with the spread of strains, plasmids and transposons. More specifically, a single hyperepidemic clone of KPC-producing K. pneumoniae [sequence type 258 (ST258)] has been identified extensively worldwide, indicating that it may have contributed to the spread of the bla KPC genes [2]. These genes have usually been identified in large plasmids varying in size and structure. There have been sporadic cases of in vivo transfer of a KPC-encoding plasmid between species [3,4] as well as reports on the detection of the same plasmid in different genera co-existing in the same patient [5,6]. In addition, at least two outbreaks involving several different genera of Enterobacteriaceae sharing the same promiscuous KPC-2-encoding plasmid have been described, one in China [7] and one in the USA [8]. Furthermore, the bla KPC genes are typically located on mobile genetic elements, specifically within a Tn3-type transposon known as Tn4401, which is thought to be at the origin of bla KPC dissemination. This structure facilitates the transfer of the gene between plasmids and across bacterial species and has been detected in isolates from diverse geographic locations [9]. Although KPC enzymes are mostly identified from K. pneumoniae, they have also been reported from a variety of hosts, including other Enterobacteriaceae and Pseudomonas spp. [10,11]. Here we describe the in vivo transfer of a bla KPC-2 -encoding plasmid from a K. pneumoniae to an Enterobacter aerogenes fecal colonizer in the same patient. 2. Materials and methods All patients admitted to the intensive care unit (ICU) of the University General Hospital ‘Attikon’ (Athens, Greece) are routinely screened biweekly by surveillance cultures of specimens from the rectum, urine, bronchial secretions and fluids from draining tubes. Surveillance cultures are plated on antibiotic-containing agar plates including one with ceftazidime (2 mg/mL) and one with imipenem (1 mg/mL). This surveillance protocol was introduced to optimize early empirical antibiotic therapy in these ICU patients [12]. 2.1. Bacterial strains Species identification and minimum inhibitory concentration (MIC) determination were performed using an automated system (BD Phoenix TM Automated Microbiology System; BD Diagnostic Systems, Sparks, MD). MICs of imipenem, meropenem and Journal of Global Antimicrobial Resistance 1 (2013) 35–38 A R T I C L E I N F O Article history: Received 19 December 2012 Received in revised form 28 January 2013 Accepted 7 February 2013 Keywords: Enterobacter aerogenes KPC Plasmid Transferable Conjugation Carbapenemases A B S T R A C T Here we describe a case of in vivo horizontal interspecies transmission of a KPC-2-producing plasmid from a Klebsiella pneumoniae to an Enterobacter aerogenes strain in the same patient. The patient’s gut flora initially contained a carbapenem-susceptible E. aerogenes strain and 10 days after admission a KPC-2-positive K. pneumoniae. Three months after admission, a KPC-2-positive E. aerogenes was identified in fecal surveillance cultures. This isolate was isogenic with the initial E. aerogenes and contained a KPC-2-coding plasmid identical to that of the K. pneumoniae. The patient developed bacteraemia by the KPC-2-positive K. pneumoniae 17 days after her first colonization. In vivo horizontal transmission of bla KPC -carrying plasmids between bacterial species underscores the importance of antibiotic stewardship along with implementa- tion of infection control measures for the containment of KPC-producers. ß 2013 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved. § These data were presented in part at the 20th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), 10–13 April 2010, Vienna, Austria (abstract number P1279). * Corresponding author. Present address: 6th Department of Internal Medicine, Hygeia Hospital, 4 Erythrou Stavrou Street & Kifisias Avenue, 151 23 Marousi, Athens, Greece. Tel.: +30 210 68 67 946; fax: +30 210 68 67 733. E-mail address: e.giamarellou@hygeia.gr (H. Giamarellou). Contents lists available at SciVerse ScienceDirect Journal of Global Antimicrobial Resistance jo u rn al h om ep age: w ww.els evier.c o m/lo c ate/jg ar 2213-7165/$ – see front matter ß 2013 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jgar.2013.02.003