Infections due to antibiotic-resistant bacteria are threatening modern health care. However, estimating their incidence, complications, and attributable mortality is challenging. We aimed to estimate the burden of infections caused by antibiotic-resistant bacteria of public health concern in countries of the EU and European Economic Area (EEA) in 2015, measured in number of cases, attributable deaths, and disability-adjusted life-years (DALYs). We estimated the incidence of infections with 16 antibiotic resistance-bacterium combinations from European Antimicrobial Resistance Surveillance Network (EARS-Net) 2015 data that was country-corrected for population coverage. We multiplied the number of bloodstream infections (BSIs) by a conversion factor derived from the European Centre for Disease Prevention and Control point prevalence survey of health-care-associated infections in European acute care hospitals in 2011-12 to estimate the number of non-BSIs. We developed disease outcome models for five types of infection on the basis of systematic reviews of the literature. From EARS-Net data collected between Jan 1, 2015, and Dec 31, 2015, we estimated 671 689 (95% uncertainty interval [UI] 583 148-763 966) infections with antibiotic-resistant bacteria, of which 63·5% (426 277 of 671 689) were associated with health care. These infections accounted for an estimated 33 110 (28 480-38 430) attributable deaths and 874 541 (768 837-989 068) DALYs. The burden for the EU and EEA was highest in infants (aged <1 year) and people aged 65 years or older, had increased since 2007, and was highest in Italy and Greece. Our results present the health burden of five types of infection with antibiotic-resistant bacteria expressed, for the first time, in DALYs. The estimated burden of infections with antibiotic-resistant bacteria in the EU and EEA is substantial compared with that of other infectious diseases, and has increased since 2007. Our burden estimates provide useful information for public health decision-makers prioritising interventions for infectious diseases. European Centre for Disease Prevention and Control.

The objective of this study was to characterize New Delhi metallo-β-lactamase (NDM)-producing Enterobacteriaceae isolates reported in Poland in 2012–14. Representative isolates were typed by PFGE and MLST. NDM and other β-lactamase genes were amplified and sequenced. Plasmids with bla_NDM genes were analysed by nuclease S1 plus hybridization profiling, by transfer assays and by PCR-based replicon typing. The bla_NDM genetic context was studied by PCR mapping assays. Of 374 cases of infection/colonization with NDM-positive Enterobacteriaceae identified in 2012–14, 370 cases in 40 hospitals, 10 outpatient clinics and 1 nursing home were associated with a Klebsiella pneumoniae outbreak with epicentres in Poznań and Warsaw. The outbreak strain of K. pneumoniae ST11 was similar to an isolate from the Czech Republic from 2013. Like the Czech strain, many of the isolates had two bla_NDM-1-carrying IncFII- and IncR-type plasmids of variable size, sharing a bla_NDM-1-containing segment. The early isolates also produced CTX-M-15 co-encoded by the IncR-type plasmids, and differentiated later by extensive plasmid rearrangements. Four other NDM cases were reported in 2013, three being associated with arrivals from Montenegro, India or Afghanistan. The Indian Escherichia coli ST448 NDM-5 isolate revealed similarity to a recent isolate from Spain, including the bla_NDM genetic context observed previously in E. coli strains in Poland and France (of Congolese and Indian origins, respectively). The Afghani Proteus mirabilis was the second isolate of this species with a chromosomal bla_NDM-1 location. The largest NDM outbreak in a non-endemic country has been observed, being an alarming phenomenon in resistance epidemiology in Poland.

After the first report in May 2008, the National Reference Center for Susceptibility Testing confirmed 113 cases of infection or colonization by KPC-producing members of the family Enterobacteriaceae in Poland by the end of 2009. The vast majority of patients were found in 18 hospitals; three patients were diagnosed at outpatient clinics. Most of the institutions were in the Warsaw area, including three hospitals with the highest numbers of cases. When available, the data on previous hospitalizations often indicated that these hospitals were the probable acquisition sites; one patient arrived from New York. The group of 119 unique isolates consisted of Klebsiella pneumoniae (n = 114), followed by Klebsiella oxytoca (n = 3), and Escherichia coli (n = 2). The K. pneumoniae isolates were dominated by the clone sequence type 258 (ST258) (n = 111); others were ST11 and ST23. The ST258 group was heterogeneous, with 28 pulsed-field gel electrophoresis (PFGE) subtypes, ∼25 plasmid profiles, and nine β-lactamase patterns differing by KPC variants (KPC-2 mainly), and SHV-12, CTX-M-3, and TEM-1-like enzymes. Plasmids carrying bla_KPC genes varied in size (∼48 to 250 kb), structure, and conjugation potential. Transferable IncFII_K plasmids of ∼110 to 160 kb, probably pKpQIL or its derivatives, were observed in all K. pneumoniae clones and in K. oxytoca. Also prevalent were nontypeable pETKp50-like plasmids of ∼50 kb, found in K. pneumoniae ST258 and E. coli isolates (ST93 and ST224). Two K. pneumoniae-E. coli pairs from single patients might represent the in vivo transfer of such plasmids. The striking diversity of KPC producers at the early stage of dissemination could result from several introductions of these bacteria into the country, their multidirectional evolution during clonal spread, and transfer of the plasmids.

The significant increase of the linezolid-resistant enterococci (LRE) has been observed in Polish hospitals since 2012 and our study aimed at elucidating the possible reasons for this phenomenon. Polish LRE isolates were analysed by multilocus-sequence typing (MLST) and multiple locus variable-number tandem repeat (VNTR) analysis (MLVA), polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) to establish clonal relatedness and mechanism of linezolid resistance, respectively. Fifty analysed LRE (2008–2015) included mostly Enterococcus faecium (82%) and Enterococcus faecalis (16%). Enterococcus faecium belonged to the hospital-adapted lineages 17/18 and 78, while E. faecalis isolates represented ST6, a hospital-associated type, and ST116, found in both humans and food-production animals. The G2576T 23S rRNA mutation was the most frequent (94%) mechanism of linezolid/tedizolid resistance of LRE. None of the isolates carried the plasmid-associated gene of Cfr methyltransferase, whereas optrA, encoding the ABC-type drug transporter, was identified in two E. faecalis isolates. In these isolates, optrA was located on a plasmid, transferable to both E. faecium and E. faecalis, whose partial (36.3 kb) sequence was 100% identical to the pE394 plasmid, identified previously in China in both clinical and farm animal isolates. The optrA–E. faecium transconjugant displayed a significant growth deficiency, in contrast to the optrA–E. faecalis. Our study indicates the role of mutation acquisition by hospital-adapted clones of enterococci as a major driver of increasing resistance to linezolid and tedizolid. Transferability and apparent lack of a biological cost of resistance suggest that E. faecalis may be a natural reservoir of optrA, an emerging mechanism of oxazolidinone resistance.