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ABSTRACTClinical isolates of Klebsiella pneumoniaeproducing NDM-1 carbapenemase from India (n= 22), the United Kingdom (n= 13), and Sweden (n= 4) were subjected to multilocus sequence typing (MLST), automated repetitive sequence-based PCR (rep-PCR), serotyping, virulence gene screening, and plasmid replicon typing. The most frequently detected MLST sequence types (STs) were ST14 (n= 13; all serotype K2), ST11, ST149, ST231, and ST147. The correlation between MLST and automated rep-PCR was excellent. IncA/C was the most frequently detected plasmid replicon type (n= 14). ST14, ST11, and other successful clones may be important for the dissemination of blaNDM-1.

Clinical isolates of Klebsiella pneumoniae producing NDM-1 carbapenemase from India (n = 22), the United Kingdom (n = 13), and Sweden (n = 4) were subjected to multilocus sequence typing (MLST), automated repetitive sequence-based PCR (rep-PCR), serotyping, virulence gene screening, and plasmid replicon typing. The most frequently detected MLST sequence types (STs) were ST14 (n = 13; all serotype K2), ST11, ST149, ST231, and ST147. The correlation between MLST and automated rep-PCR was excellent. IncA/C was the most frequently detected plasmid replicon type (n = 14). ST14, ST11, and other successful clones may be important for the dissemination of blaNDM-1.

ABSTRACTScandinavia is considered a region with a low prevalence of antimicrobial resistance. However, the number of multidrug-resistant (MDR) Gram-negative bacteria is increasing, including metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa. In this study MBL-producing P. aeruginosaisolates identified in Norway (n= 4) and Sweden (n= 9) from 1999 to 2007 were characterized. Two international clonal complexes (CC), CC111 (n= 8) and CC235 (n= 2), previously associated with MBL-producing isolates, were dominant. CC111 isolates (ST111/229; serotype O12; blaVIM-2) included clonally related isolates identified in Skåne County, Sweden (n= 6), and two isolates associated with importation from Greece and Denmark. In all CC111 isolates, blaVIM-2was located in integron In59.2or In59variants. The two CC235 isolates (ST235/ST230; serotype O11; blaVIM-4) were imported from Greece and Cyprus, were possibly clonally related, and carried blaVIM-4in two different integron structures. Three isolates imported from Ghana (ST233; serotype O6; blaVIM-2), Tunisia (ST654; serotype O11; blaVIM-2), and Thailand (ST260; serotype O6; blaIMP-14) were clonally unrelated. ST233 was part of a new CC (CC233) that included other MBL-producing isolates, while ST654 could also be part of a new CC associated with MBL producers. In the isolates imported from Ghana and Tunisia, blaVIM-2was part of unusual integron structures lacking the 3′ conserved segment and associated with transposons. The blaVIMgene was found to be located on the chromosome in all isolates. Known risk factors for acquisition of MBL were reported for all patients except one. The findings suggest that both import of successful international clones and local clonal expansion contribute to the emergence of MBL-producing P. aeruginosain Scandinavia.

ABSTRACTA Swedish patient of Indian origin traveled to New Delhi, India, and acquired a urinary tract infection caused by a carbapenem-resistant Klebsiella pneumoniaestrain that typed to the sequence type 14 complex. The isolate, Klebsiella pneumoniae05-506, was shown to possess a metallo-β-lactamase (MBL) but was negative for previously known MBL genes. Gene libraries and amplification of class 1 integrons revealed three resistance-conferring regions; the first contained blaCMY-4flanked by ISEcP1and blc. The second region of 4.8 kb contained a complex class 1 integron with the gene cassettes arr-2, a new erythromycin esterase gene; ereC; aadA1; and cmlA7. An intact ISCR1element was shown to be downstream from the qac/sulgenes. The third region consisted of a new MBL gene, designated blaNDM-1, flanked on one side by K. pneumoniaeDNA and a truncated IS26element on its other side. The last two regions lie adjacent to one another, and all three regions are found on a 180-kb region that is easily transferable to recipient strains and that confers resistance to all antibiotics except fluoroquinolones and colistin. NDM-1 shares very little identity with other MBLs, with the most similar MBLs being VIM-1/VIM-2, with which it has only 32.4% identity. As well as possessing unique residues near the active site, NDM-1 also has an additional insert between positions 162 and 166 not present in other MBLs. NDM-1 has a molecular mass of 28 kDa, is monomeric, and can hydrolyze all β-lactams except aztreonam. Compared to VIM-2, NDM-1 displays tighter binding to most cephalosporins, in particular, cefuroxime, cefotaxime, and cephalothin (cefalotin), and also to the penicillins. NDM-1 does not bind to the carbapenems as tightly as IMP-1 or VIM-2 and turns over the carbapenems at a rate similar to that of VIM-2. In addition to K. pneumoniae05-506, blaNDM-1was found on a 140-kb plasmid in an Escherichia colistrain isolated from the patient's feces, inferring the possibility of in vivo conjugation. The broad resistance carried on these plasmids is a further worrying development for India, which already has high levels of antibiotic resistance.

ABSTRACTKlebsiella pneumoniaecarbapenemase (KPC)-producing Enterobacteriaceaehave become more common in the United States and throughout the world. We used pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) to examine the molecular epidemiology of KPC-producing K. pneumoniaeisolates sent to the Centers for Disease Control and Prevention (CDC) for reference testing from 1996 to 2008. A dominant strain, sequence type 258 (ST 258), was found and likely accounts for 70% of the CDC's K. pneumoniaePFGE database. Isolates with PFGE patterns related to ST 258 were identified in 10 of the 19 U.S. states currently reporting KPC-producing K. pneumoniae, in addition to one isolate from Israel. KPC subtyping and analysis of the surrounding genetic environment were subsequently performed on 23 representative isolates. Thirteen isolates identified as ST 258 possessed either blaKPC-2or blaKPC-3and some variability in the Tn4401element upstream of the blaKPCgene. Escherichia coliDH10B was successfully transformed by electroporation with KPC-encoding plasmid DNA from 20 of the 23 isolates. Restriction analysis of plasmid DNA prepared from transformants revealed a diversity of band patterns, suggesting the presence of different plasmids harboring the blaKPCgene, even among isolates of the same ST.

Patients with traveler’s diarrhea (TD) can acquire extended-spectrum-beta-lactamase (ESBL)-producing members of the Enterobacterales(EPE) during travel to areas of endemicity. The aim of the present study was to investigate the prevalence and characteristics of EPE carriage in travelers from southern Sweden who were sampled for bacterial diagnostics of TD compared to those of EPE carriage 10 years ago. Clinical samples sent for culture of common causes of bacterial enterocolitis, if the referral stated foreign travel, were included in the study.

Invasive infections due to extended-spectrum-β-lactamase- and pAmpC-producing Escherichia coli(ESBL/pAmpC-EC) are an important cause of morbidity, often caused by the high-risk clone sequence type (ST131) and isolates classified as extraintestinal pathogenic E. coli(ExPEC). The relative influence of host immunocompetence versus microbiological virulence factors in the acquisition and outcome of bloodstream infections (BSI) is poorly understood. Herein, we used whole-genome sequencing on 278 blood culture isolates of ESBL/pAmpC-EC from 260 patients with community-onset BSI collected from 2012 to 2015 in Stockholm to study the association of virulence genes, sequence types, and antimicrobial resistance with severity of disease, infection source, ESBL/pAmpC-EC BSI low-risk patients, and patients with repeated episodes.

Extended-spectrum β-lactamase-producing Enterobacteriaceae(EPE) are a major cause of bloodstream infections, and the colonization rate of EPE in the gut microbiota of individuals lacking prior hospitalization or comorbidities is increasing. In this study, we performed an in-depth investigation of the temporal dynamics of EPE and their plasmids during one year by collecting fecal samples from three patients initially seeking medical care for urinary tract infections.