We report high rates of bacteremia and colonization with ESBL-producing Enterobacteriaceae at admission to our institution, which may undermine infection-control measures and complicate the selection of empirical treatment.

Carbapenem resistance due to KPC has rarely been observed outside the United States. We noticed a sharp increase in carbapenem-resistant Klebsiella pneumoniae strains possessing KPC in Tel Aviv Medical Center from 2004 to 2006. Sixty percent of the isolates belonged to a single clone susceptible only to gentamicin and colistin and carried the bla KPC-3 gene, while almost all other clones carried the bla KPC-2 gene. This rapid dissemination of KPC outside the United States is worrisome.

We have determined the entire DNA sequence of plasmid pKpQIL, the bla KPC-3 -carrying plasmid harbored by the carbapenem-resistant Klebsiella pneumoniae clone sequence type 258 (ST 258) in Israel. pKpQIL is a 113,637-bp, self-transmissible plasmid that belongs to the incompatibility group IncFII. It consists of a large backbone of a pKPN4-like plasmid and carries the bla KPC-3 -containing Tn4401a transposon of a pNYC-like plasmid.

Carbapenem resistance in Escherichia coli is rare. We report four genetically unrelated carbapenem-resistant E. coli isolates cultured from four patients hospitalized in Tel Aviv Medical Center. PCR, sequencing, and Southern blot analysis identified KPC-2 as the imipenem-hydrolyzing enzyme in all four strains, carried on different plasmids with a possible common origin. This is the first discovery of KPC-2 in E. coli and the first report of this enzyme originating outside the United States.Carbapenem resistance in Escherichia coli does not occur naturally, and acquired resistance is rare in this species (15). Few cases of carbapenem-resistant E. coli strains have been reported. The first reported case in 1999 described the occurrence of outer-membrane protein deficiency coupled with the plasmid-mediated class C ␤-lactamase CMY (17). Carbapenemhydrolyzing, plasmid-mediated metallo-␤-lactamases in clinical E. coli strains from various parts of the world have been reported (6,11,16,19), but class A carbapenemases in E. coli have been described in only one case, involving KPC-3 acquisition in a patient in the United States during imipenem therapy (7).A high prevalence of extended-spectrum-␤-lactamase-producing E. coli clinical isolates has been observed and studied in our institution (5), but carbapenem resistance in this species has never been observed. In February 2005, an imipenemresistant E. coli strain (MIC, 32 g/ml) was isolated from a urine culture from a 75-year-old woman with multiple chronic illnesses hospitalized at Tel Aviv Medical Center due to syncope. During September and October 2005, three additional carbapenem-resistant E. coli isolates were isolated at our hospital. We examined the epidemiological and genetic relatedness and the clinical scenario as well as the enzymatic mechanism leading to this resistance. MATERIALS AND METHODSSetting, bacterial strains, and antibiotic susceptibility testing. Tel Aviv Medical Center is a 1,200-bed tertiary care teaching hospital, with 70,000 admissions annually. Four clinical isolates of Escherichia coli were isolated from four patients hospitalized during 2005 in our institution. The patients' relevant clinical data were collected from their medical records. Antibiotic susceptibilities were determined by Vitek-2 (BioMerieux Inc., Marcy, France). MICs of all carbapenems (imipenem, meropenem, and ertapenem) were determined by Etest (AB Biodisk, Solna, Sweden).PFGE. The genetic relatedness of the four E. coli isolates was analyzed by pulsed-field gel electrophoresis (PFGE). Bacterial DNA was prepared and cleaved with 20U SpeI endonuclease (New England Biolabs, Boston, MA) as previously described (5), and DNA macrorestriction patterns were visually compared and interpreted according to the criteria established by Tenover et al. (18).Carbapenemase analysis and IEF of ␤-lactamases. Visualization of imipenem-hydrolyzing ␤-lactamase activity by the E. coli clinical isolates was performed by an imipenem inactivation bioassay (21) performed on Mueller-Hinton agar plates ...

The spread of carbapenem-resistant members of the Enterobacteriaceae family (CRE) harboring carbapenemases is an emerging public health threat. As KPC-producing Klebsiella species are endemic in our tertiary care hospital, we aimed to evaluate a PCR-based surveillance test for identification of rectal carriage of KPC-producing CRE. We conducted a surveillance study between May and December 2007. Rectal swabs were collected from patients known to harbor CRE and from contacts of newly discovered patients harboring CRE. Specimens were evaluated by culture and by PCR analysis for bla KPC and were defined as positive if CRE was cultured and bla KPC was identified. Discrepant results between the culture and PCR analysis were resolved by subculturing, repeating the PCR, and performing a hydrolysis assay. Positive CRE cultures prior or subsequent to the time of sampling for the study were also taken into consideration. Sensitivity, specificity, and time to result were calculated. A total of 755 swabs were included. Concordant results were documented for 735 specimens; 51 were positive as determined by both PCR and culture. Discrepancies existed for 20 swabs; 9 were bla KPC negative and CRE culture positive, and 11 were bla KPC positive and CRE culture negative. After repeat testing, a total of 64 samples were classified as bla KPC -positive CRE. The sensitivity and specificity of the PCR analysis were 92.2% and 99.6%, respectively, and those of the culture were 87.5% and 99.4%, respectively. Over the last 3 months of the study, the sensitivity of the PCR improved to 96.3%, versus 77.8% for culture. Time to result was 30 h for the PCR and 60 h (negative) and 75 h (positive) for the CRE culture. bla KPC PCR-based testing is a useful method for the surveillance of KPC-producing CRE. Its main advantage over culturing is a shorter time to result, and it may prove to be more sensitive.KPC-mediated carbapenem resistance in members of the Enterobacteriaceae has emerged recently in Israel, as observed in clinical strains of Escherichia coli (14), Enterobacter cloacae (13), and Klebsiella pneumoniae (10). An epidemic clone of KPC-3-producing Klebsiella pneumoniae, possessing resistance to nearly all antimicrobial agents, excluding gentamicin and colistin, has spread in all major Israeli hospitals (15). Infections caused by this strain have been associated with greater than 40% in-hospital mortality (23). As part of our extensive infection control efforts to limit the spread of this highly epidemic strain in the hospital, we aimed to implement a policy of early detection of carriers by screening for gastrointestinal carriage of this pathogen.Active surveillance has been shown to be an effective infection control strategy with other antibiotic-resistant pathogens, such as methicillin (meticillin)-resistant Staphylococcus aureus (4, 5) and vancomycin-resistant enterococci (16). The use of culture-based methods for detection of carbapenem-resistant members of the Enterobacteriaceae family (CRE) from rectal or stool surveillance sampl...

Klebsiella pneumoniae carbapenemase (KPC) 3–producing Escherichia coli was isolated from a carrier of KPC-3–producing K. pneumoniae. The KPC-3 plasmid was identical in isolates of both species. The patient's gut flora contained a carbapenem-susceptible E. coli strain isogenic with the KPC-3–producing isolate, which suggests horizontal interspecies plasmid transfer.

Our findings demonstrate the presence of pKpQIL, a 105 kb KPC-3- and TEM-1-encoding plasmid, in the XDR K. pneumoniae epidemic strain in Israel. pKpQIL is unique and appears consistently in all isolates of this clone over the years. The extensive beta-lactam resistance phenotype of this clone is primarily mediated by this single self-transmissible plasmid.

Medical Center during 2005 and 2006, parallel to the emergence of the KPC-3-producing K. pneumoniae sequence type 258 (ST 258). We aimed to study the molecular epidemiology of these isolates and to characterize their bla KPC -carrying plasmids and their origin. Ten isolates (8 KPC-2 and 2 KPC-3 producing) were studied. All isolates were extremely drug resistant. They possessed the bla KPC gene and varied in their additional beta-lactamase contents. The KPC-2-producing strains belonged to three different sequence types: ST 340 (n ‫؍‬ 2), ST 277 (n ‫؍‬ 2), and a novel sequence type, ST 376 (n ‫؍‬ 4). Among KPC-3-producing strains, a single isolate (ST 327) different from ST 258 was identified, but both strains carried the same plasmid (pKpQIL). The KPC-2-encoding plasmids varied in size (45 to 95 kb) and differed among each of the STs. Two of the Klebsiella bla KPC-2 -carrying plasmids were identical to plasmids from Escherichia coli, suggesting a common origin of these plasmids. These data indicate that KPC evolution in K. pneumoniae is related to rare events of interspecies spread of bla KPC-2 -carrying plasmids from E. coli followed by limited clonal spread, whereas KPC-3 carriage in this species is related almost strictly to clonal expansion of ST 258 carrying pKpQIL.