To follow the epidemic of KPC-2-producing Klebsiella pneumoniae in Greece. KPC-2-producing isolates (n = 378) were collected during January 2009–April 2010 in 40 Greek hospitals. bla_KPC and bla_VIM were detected by PCR. Carbapenemase production was confirmed by spectrophotometry. Sequences flanking bla_KPC-2 and their plasmid carriers were studied. Isolates were typed by PFGE and multilocus sequence typing (MLST). All 378 isolates were bla_KPC-2 positive; 18 also carried bla_VIM-1/VIM-4. Higher isolation frequencies were observed in Athens and Crete. Isolates were classified into 13 PFGE types and 11 sequence types (STs). ST258 was predominant (n = 322), followed by ST147 (n = 20), ST383 (n = 9), ST133 (n = 6), ST274 (n = 4) and ST323 (n = 3). Of the remaining isolates, seven were distributed into five STs (11, 17, 340 and the novel 494 and 495) and seven were not typed. bla_KPC-2 could not be transferred from ST258 isolates, in contrast to isolates of ST17, ST133, ST147, ST274, ST494 and ST495. All bla_KPC-2-encoding plasmids were of similar size (∼100 kb) and showed indistinguishable restriction fragment length polymorphism (RFLP) patterns except those from the ST340 isolates. Sequences flanking bla_KPC-2 revealed that the Tn4401a isoform was present in plasmids from all STs except ST340 containing Tn4401b. Co-production of VIM enzymes was observed in isolates of ST147, ST323 and ST383. Apart from the epidemic of KPC-2-producing K. pneumoniae belonging to ST258 in Greece, diffusion of bla_KPC-2 to at least 10 additional STs has taken place. Notably, strains from three of the latter STs (147, 323 and 383) were found to carry both bla_KPC-2 and bla_VIM.

Changes in hospitals’ daily practice due to COVID-19 pandemic may have an impact on antimicrobial resistance (AMR). We aimed to assess this possible impact as captured by the Greek Electronic System for the Surveillance of Antimicrobial Resistance (WHONET-Greece). Routine susceptibility data of 17,837 Gram-negative and Gram-positive bacterial isolates from blood and respiratory specimens of hospitalized patients in nine COVID-19 tertiary hospitals were used in order to identify potential differences in AMR trends in the last three years, divided into two periods, January 2018–March 2020 and April 2020–March 2021. Interrupted time-series analysis was used to evaluate differences in the trends of non-susceptibility before and after the changes due to COVID-19. We found significant differences in the slope of non-susceptibility trends of Acinetobacter baumannii blood and respiratory isolates to amikacin, tigecycline and colistin; of Klebsiella pneumoniae blood and respiratory isolates to meropenem and tigecycline; and of Pseudomonas aeruginosa respiratory isolates to imipenem, meropenem and levofloxacin. Additionally, we found significant differences in the slope of non-susceptibility trends of Staphylococcus aureus isolates to oxacillin and of Enterococcus faecium isolates to glycopeptides. Assessing in this early stage, through surveillance of routine laboratory data, the way a new global threat like COVID-19 could affect an already ongoing pandemic like AMR provides useful information for prompt action.

Carbapenemase-producing Klebsiella pneumoniae (CPKP) emerged in Greece in 2002 and became endemic thereafter. Driven by a notable variability in the phenotypic testing results for carbapenemase production in K. pneumoniae isolates from the intensive care units (ICUs) of our hospital, we performed a study to assess the molecular epidemiology of CPKP isolated between 2016 and 2019 using pulse-field gel electrophoresis (PFGE) including isolates recovered from 165 single patients. We investigated the molecular relatedness among strains recovered from rectal surveillance cultures and from respective subsequent infections due to CPKP in the same individual (48/165 cases). For the optimal interpretation of our findings, we carried out a systematic review regarding the clonality of CPKP isolated from clinical samples in ICUs in Europe. In our study, we identified 128 distinguishable pulsotypes and 17 clusters that indicated extended dissemination of CPKP within the hospital ICU setting throughout the study period. Among the clinical isolates, 122 harbored KPC genes (74%), 2 harbored KPC+NDM (1.2%), 38 harbored NDM (23%), 1 harbored NDM+OXA-48 (0.6%), 1 harbored NDM+VIM (0.6%) and 1 harbored the VIM (0.6%) gene. Multiple CPKP strains in our hospital have achieved sustained transmission. The polyclonal endemicity of CPKP presents a further threat for the selection of pathogens resistant to last-resort antimicrobial agents.

Background: Antimicrobial resistance (AMR) changes over time and continuous monitoring provides insight on trends to inform both empirical treatment and public health action. Aims: To survey trends in relative isolation frequency (RIF) and AMR among key bloodstream pathogens using data from the Greek Electronic System for the Surveillance of AMR (WHONET-Greece). Methods: This observational study looked into routine susceptibility data of 50,488 blood culture isolates from hospitalised patients in 25 tertiary hospitals, participating in the WHONET-Greece for trends over time between January 2010 and December 2017. Only the first isolate per species from each patient was included. Hospital wards and intensive care units (ICUs) were analysed separately. Results: During the study, the RIF of Acinetobacter baumannii increased in wards, as did the proportion of A. baumannii isolates, which were non-susceptible to most antibiotics in both wards and ICUs. Coincidently, Klebsiella pneumoniae RIF declined while the respective rates of non-susceptible isolates to carbapenems and gentamicin increased. Pseudomonas aeruginosa RIF remained stable but decreasing proportions of non-susceptible isolates to all studied antibiotics, except imipenem were observed. Escherichia coli RIF increased as did the proportion of isolates non-susceptible to third-generation cephalosporins, carbapenems and fluoroquinolones. Concerning Staphylococcus aureus, a decline in the percentage of meticillin resistant isolates in ICUs was found, while the percentages of Enterococcus faecium isolates with non-susceptibility to vancomycin stayed stable. Conclusions: Recognising these trends over time is important, since the epidemiology of AMR is complex, involving different ‘bug and drug’ combinations. This should be taken into consideration to control AMR.