Abstract
We report 570 carbapenemase-producing Klebsiella pneumoniae (CPKP) clinical isolates in a 1,040-bed Greek tertiary hospital during 2004 to 2010. The first CPKP (VIM-producing) was isolated in September 2004. Despite initial containment, VIM producers have become endemic since 2006. KPC-producing K. pneumoniae was first isolated in August 2007 from a patient who came from Israel, spread rapidly, and outcompeted VIM. Overall, 267 (47%) VIM-producing and 301 (53%) KPC-producing strains were isolated, including 141 (24.7%) from patients with bacteraemia. Two isolates carrying both VIM and KPC were isolated in two consecutive months in 2009, but not since. The prevalence of CPKP increased from 0% in 2003 to 38.3% in 2010 (p<0.0001). All genotyped KPC producers harboured blaKPC-2 and belonged to two clones, among which the hyperepidemic Greek clone, related to those from the United States and Israel, predominated. Most metallo-beta-lactamase (MBL) producers carried the blaVIM-1 gene and belonged to several clones, whereas all but one isolate with blaVIM-12 were clustered within a five-month period, arising from one clone. Resistance to non-beta-lactam antibiotics was also increased among CPKP. They were almost invariably resistant to ciprofloxacin and trimethoprim-sulfamethoxazole. Resistance to colistin increased from 3.5% (4/115) in 2008 to 20.8% (25/120) in 2010, and resistance to tigecycline also increased. Following reinforcement of infection control measures, prevalence of CPKP (mainly KPC) has been reduced since mid-2009 (from 46% in 2009 to 38.3% in 2010). In view of the exhaustion of available therapies, investment in infection control resources and optimal antibiotic use is urgently required.
Highlights
Carbapenems are important therapeutic agents for treating infections caused by multi-drug resistant Gram-negative bacteria
Carbapenemase-producing K. pneumoniae (CPKP) were isolated in all departments and 46.1% of isolates derived from two units: the eight-bed intensive care unit (ICU) (154 isolates; 27.0%) and the 10-bed organ transplant unit (109 isolates; 19.1%)
The first CPKP was isolated in September 2004 from an infected wound of a patient who had been transferred from the ICU to the orthopedic ward; The minimum inhibitory concentration (MIC) of imipenem and meropenem were 4 and 2 mg/L, respectively
Summary
Carbapenems are important therapeutic agents for treating infections caused by multi-drug resistant Gram-negative bacteria. Their efficacy, is threatened by the emergence of resistant isolates. Other mechanisms of resistance to carbapenems include the combination of extended spectrum beta-lactamase (ESBL) production with porin changes and/or upregulated efflux pumps (the latter common among carbapenemresistant Pseudomonas aeruginosa) [3,4]. The most prevalent carbapenemases are the molecular class B metallo-beta-lactamases (MBLs), mainly of VIM- and IMP-type, and the (class A) K. pneumoniae-carbapenemases (KPCs) [5]. Carbapenemase-producing K. pneumoniae (CPKP) have been isolated worldwide, including most European countries [8]; CPKP are nowadays endemic in Greece (both VIM and KPC) and Israel (KPC). The presence of KPC in Israel was first reported in 2005 [9] and in Greece in 2007 [10]
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