A total of 904 consecutive nosocomial isolates of Escherichia coli and Klebsiella pneumoniae collected from 28 Russian hospitals were screened for production of extended-spectrumβ -lactamases (ESBLs). The ESBL phenotype was detected in 78 (15.8%) E. coli and 248 (60.8%) K. pneumoniae isolates. One hundred fifteen isolates carried the genes for CTX-M-type β-lactamases, which, as shown by PCR-restriction fragment length polymorphism analysis, were distributed into the two genetic groups of CTX-M-1 (93%)- and CTX-M-2 (7%)-related enzymes. Isolates producing the enzymes of the first group were found in 20 hospitals from geographically distant regions of the country and were characterized by considerable diversity of genetic types, as was demonstrated by enterobacterial repetitive consensus PCR typing. Within this group the CTX-M-3 and the CTX-M-15β -lactamases were identified. In contrast, the enzymes of the CTX-M-2 group (namely, CTX-M-5) were detected only in eight clonally related E. coli isolates from a single hospital. Notably, the levels of resistance to ceftazidime were remarkably variable among the CTX-M producers. This study provides further evidence of the global dissemination of CTX-M type ESBLs and emphasizes the need for their epidemiological monitoring.

Acquired carbapenemases are emerging resistance determinants in Gram-negative pathogens, including Enterobacteriaceae, Pseudomonas aeruginosa and other Gram-negative non-fermenters. A consistent number of acquired carbapenemases have been identified during the past few years, belonging to either molecular class B (metallo-β-lactamases) or molecular classes A and D (serine carbapenemases), and genes encoding these enzymes are associated with mobile genetic elements that allow their rapid dissemination in the clinical setting. Therefore, detection and surveillance of carbapenemase-producing organisms have become matters of major importance for the selection of appropriate therapeutic schemes and the implementation of infection control measures. As carbapenemase production cannot be simply inferred from the resistance profile, criteria must be established for which isolates should be suspected and screened for carbapenemase production, and for which tests (phenotypic and/or genotypic) should be adopted for confirmation of the resistance mechanism. Moreover, strategies should be devised for surveillance of carbapenemase producers in order to enable the implementation of effective surveillance programmes. The above issues are addressed in this article, as a follow-up to an expert meeting on acquired carbapenemases that was recently organized by the ESCMID Study Group for Antibiotic Resistance Surveillance.

Background: Klebsiella pneumoniae, which is frequently associated with hospital- and community-acquired infections, contains multidrug-resistant (MDR), hypervirulent (hv), non-MDR/non-hv as well as convergent representatives. It is known that mostly international high-risk clonal lineages including sequence types (ST) 11, 147, 258, and 307 drive their global spread. ST395, which was first reported in the context of a carbapenemase-associated outbreak in France in 2010, is a less well-characterized, yet emerging clonal lineage.Methods: We computationally analyzed a large collection ofK. pneumoniaeST395 genomes (n = 297) both sequenced in this study and reported previously. By applying multiple bioinformatics tools, we investigated the core-genome phylogeny and evolution of ST395 as well as distribution of accessory genome elements associated with antibiotic resistance and virulence features.Results: Clustering of the core-SNP alignment revealed four major clades with eight smaller subclades. The subclades likely evolved through large chromosomal recombination, which involved differentK. pneumoniaedonors and affected,inter alia, capsule and lipopolysaccharide antigen biosynthesis regions. Most genomes contained acquired resistance genes to extended-spectrum cephalosporins, carbapenems, and other antibiotic classes carried by multiple plasmid types, and many were positive for hypervirulence markers, including the siderophore aerobactin. The detection of “hybrid” resistance and virulence plasmids suggests the occurrence of the convergent ST395 pathotype.Conclusions: To the best of our knowledge, this is the first study that investigated a large international collection ofK. pneumoniaeST395 genomes and elucidated phylogenetics and detailed genomic characteristics of this emerging high-risk clonal lineage.

Objective. To review the basic principles and functionality of the AMRmap online resource. Materials and Methods. The AMRmap platform was developed using the R programming language and various downloadable modules – packages. The current annually updated version of EUCAST clinical breakpoints was applied for determination of categories of susceptibility to antimicrobial agents. Descriptive analysis includes calculation of absolute and relative frequencies, median values, and confidence intervals using the Wilson method. Categorical variables are compared using Fisher’s exact test and Holm correction method for multiple comparisons. The algorithms are used to visualize multiple comparisons, kernel regression for trend analysis, and algorithms for finding associative rules. Results. The developed surveillance system includes modules for filtering, analyzing and visualizing antibiotic resistance data. The filters allow creating a sample of data with a specific list of parameters. A tab-based separation of analysis and visualization options ensure efficient stepwise evaluation of results. Data saving and sharing functions are also provided. Conclusions. This web-based informatics system provides a convenient way to AMR data from prospective microbiological surveillance studies in Russia. AMRmap can be accessed at https://amrmap.ru.