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Introduction: Carbapenem-resistant Klebsiella pneumoniae are a major problem. We aimed to investigate carbapenemase-encoding genes and transferable mcr-1 genes among 57 carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates from hospitalized patients., Methodology: Antibiotic susceptibility tests were performed by Phoenix (BD). Results for ertapenem and colistin were confirmed by gradient diffusion and microdilution methods. Carbapenemase and mcr-1 genes were investigated by Polymerase Chain Reaction (PCR)., Results: Thirty-two (56.14%) isolates were from intensive care units (ICU). Antibiotic resistance rates by Phoenix: 52.63% for amikacin; 73.69% trimethoprim sulfamethoxazole; 91.23% cefepime; 82.46% tigecycline; 59.65% colistin. Carbapenemases positivity: 82.45% (47) for blaOXA-48, 40.35% (23) blaOXA-55, 3.50% (2) blaOXA-51, 1.75% (1) blaOXA-23, 1.75% (1) blaOXA-24, 1.75% (1) blaIMP. blaOXA-58, blaKPC, blaNDM-1, and blaVIM were not detected. Twenty (35.08%) isolates had both blaOXA-48 and blaOXA-55. Three isolates were mcr-1 (+) and blaOXA-48 (+). One mcr-1 (+) isolates was blaOXA-51 (+). One colistin sensitive isolate determined by Phoenix, was found colistin resistant by microdilution., Conclusion: OXA-48 and OXA-55 co-harboring isolates and mcr-1 gene (+) isolates were spreading. Automated colistin susceptibility results should be confirmed by microdilution method. Resistance mechanisms in Enterobacteriaceae should be determined and the isolates should be monitored by molecular epidemiological methods. Effective infection control measures will contribute to reduce risk of antibiotic resistant bacterial infections and dissemination of antibiotic resistance., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2019 Cigdem Arabaci, Tuba Dal, Tugcan Basyigit, Neslihan Genisel, Riza Durmaz.)

Background: The Escherichia coli sequence type 131 (ST131) is a well established clone causing significant extraintestinal infections worldwide. However, no studies have been reported the phenotypic and molecular traits of ST131 isolates in comparison to other clones of E. coli from Iran. So, we determined the differences between 69 ST131 strains collected during a one year surveillance study and 84 non-ST131 isolates, including 56 clinical fluoroquinolone resistant and 28 broiler colibacillosis isolates in terms of clonality and genetic background., Results: ST131 isolates were associated with phylogroup B2 (68 out of 69 isolates, 98.4%), while clinical non-ST131 and fluoroquinolone resistant broiler isolates mainly belonged to phylogroup A. The highest virulence score was observed in ST131 clone, while they showed less diversity in virulence profiles than other clinical isolates. Almost all of the ST131 isolates (95.6%) were ExPEC and had the highest virulence scores, but their resistance scores were less than clinical non-ST131 isolates. Broiler isolates showed higher prevalence of ExPEC-associated virulence genes and CTX-M-G1/G9 resistance determinants as compared to clinical non-ST131 isolates. While bla OXA-48/NDM carbapenemases were mostly found in ST131 clone, resistance rate against ertapenem was higher among clinical non-ST131 strains. According to ERIC-based fingerprinting, the ST131 strains were more genetically similar, followed by non-ST131 and broiler isolates., Conclusions: ST131 isolates possess the ability to make a balance between clonality and extent of resistance/virulence genes content, so this phenomenon gives a fitness advantage over other E. coli clones. The broilers E. coli population poses a potential zoonotic risk which could be transmitted to the community through the food chain. A number of factors are involved in the dissemination of and infections due to ST131 clone.

Background: Urosepsis and septic shock are a critical situation leading to a mortality rate up to 30% in patients with obstructive diseases of the urinary tract., Aim: To analyze the bacterial distribution and drug resistance of pathogenic bacteria in patients with urosepsis and to provide a basis for the rational application of antibacterial drugs in clinical practice., Methods: A retrospective analysis of 94 hospitalized patients with urosepsis for 6 years was performed. The strain composition, resistance characteristics, and the antibiogram of common bacteria from positive blood and midstream urine culture were analyzed., Results: A total of 87 strains were isolated, including 65 strains (74.71%) of Gram-negative bacilli, 14 strains (16.09%) of Gram-positive cocci, and 8 strains (9.20%) of fungi. The Gram-negative bacilli included 42 strains of Escherichia coli ( E. coli ) (64.62%), among which 34 strains (80.95%) were producing ESBLs, and 14 strains (21.84%) of Klebsiella pneumoniae ( K. pneumoniae ), among which nine strains (64.29%) were producing ESBLs. The most common pathogenic bacteria, ESBL+ E. coli and K. pneumoniae strains, showed sensitivity towards imipenem, ertapenem, piperacillin/tazobactam, amikacin, and cefotetan, but were highly resistant to quinolones. The cure rate of urosepsis was 88.30%, and the susceptibility rate of septic shock was 45.47%., Significance: Gram-negative bacterial infections are the main cause of urosepsis. The mild patient group showed more E. coli (ESBL-) infections, and the number of ESBL producing E. coli isolated from the mild group showed higher drug resistance rates for aztreonam and levofloxacin compared with isolates from the severe group.

The aim of this study was to characterize the population structure of 56 OXA-48-like-producing Klebsiella pneumoniae isolates, as well as extended-spectrum β-lactamase (ESBL) and carbapenemase genes, recovered in 2014 and 2015 from 16 hospitals in southern Spain. XbaI pulsed-field gel electrophoresis and multilocus sequence typing were performed to assess clonal relatedness. Representative isolates belonging to OXA-48-like-producing and CTX-M-15-coproducing pulsotypes were selected for characterization of bla OXA-48-like - and bla CTX-M-15 -carrying plasmids by PCR-based replicon typing, IncF subtyping, whole-genome sequencing analysis, and typing of Tn 1999 structures. Forty-three OXA-48-producing isolates (77%) were recovered from clinical samples and 13 from rectal swabs. All isolates showed ertapenem MIC values of ≥1 mg/liter, although 70% remained susceptible to imipenem and meropenem. Forty-nine isolates (88%) produced OXA-48, 5 produced OXA-245, and 2 produced OXA-181. Twenty-eight different pulsotypes (5 detected in more than 1 hospital) and 16 sequence types (STs) were found. The most prevalent clones were ST15 (29 isolates [52%]) and ST11 (7 isolates [13%]). Forty-five (80%) isolates were also bla CTX-M-15 carriers. The bla CTX-M-15 gene was mostly (82%) located on IncR plasmids, although ST15 and ST11 isolates also carried this gene on IncF plasmids. The composite transposon variant Tn 1999.2 -like was the most frequent. Among ST15 and ST11 isolates, different transposon variants were observed. The bla OXA-48 gene was mainly located on IncL plasmids, although IncM plasmids were also observed. The spread of OXA-48-like-producing K. pneumoniae in southern Spain is mainly due to ST15 and ST11 clones. Variation within clonal lineages could indicate different acquisition events for both ESBL and carbapenemase traits., (Copyright © 2018 American Society for Microbiology.)

Objectives: Carbapenemase-producing Escherichia coli are a major clinical concern. The current study aimed to identify NDM-5-producing E. coli associated with community-acquired urinary tract infections (UTIs) co-harbouring extended-spectrum β-lactamases (ESBLs) and showing a phenomenon of imipenem minimum inhibitory concentration (MIC) creep., Methods: A total of 973 urine samples were collected from females aged between 18-49 years diagnosed with UTI in Northeast India (June 2014-July 2016). Isolates were identified by standard microbiological methods. The presence of bla NDM and ESBL genes was determined by PCR and sequencing. PCR-based replicon typing was performed. Plasmid stability of all β-lactamase-producers and their transformants was analysed by serial passage, and the MIC creep phenomenon was analysed by studying revertants., Results: Among 34 bla NDM-5 -positive E. coli isolates, 21 (61.8%) co harboured bla CTX-M-15 , followed by multiple combinations of genes. This study revealed diverse plasmid types (HI1, I1, FIA+FIB, FIA and Y). The strains showed progressive plasmid loss after 31 passages. Most if the isolates had MICs of 0.5μg/mL and 1μg/mL to imipenem, ertapenem and meropenem. However, on studying the MIC creep phenomenon, the MIC was found to be elevated from 0.5μg/mL to 64μg/mL and from 1μg/mL to 128μg/mL. Analysis of revertants shows that the MIC of most NDM-positive isolates was reduced to 16μg/mL after the 30th serial passage., Conclusion: This study observed a unique phenotype of NDM-producers that has not been reported previously. The observed phenomenon poses a global threat as these pathogens may evade phenotypic screening by routine laboratories., (Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

The spread of carbapenemase-producing Enterobacteriaceae in the Southwest Indian Ocean islands is poorly known. Here we describe an outbreak of colistin-resistant Enterobacter cloacae harbouring bla IMI-1 in the French overseas department of Mayotte. Between October 2015 and January 2017, all isolates of imipenem-non-susceptible E. cloacae at Mayotte Medical Center and University Hospital of Reunion Island were screened for carbapenemase production. Positive isolates were typed by pulsed-field gel electrophoresis and whole-genome sequencing (WGS)-based multilocus sequence typing (MLST), and all β-lactamase genes were identified by PCR and sequencing. Resistance profiles were determined by agar diffusion and Etest. Genetic support of the bla IMI-1 gene was determined by WGS. A total of 18 E. cloacae isolates harbouring bla IMI-1 were detected in 17 patients from Mayotte. Pulsed-field gel electrophoresis (PFGE) analysis showed 16 of the 18 strains to be clonally related and belonging to ST820. Based on clinical data, this outbreak most likely had a community origin. The bla IMI-1 gene in the 18 isolates was carried by a new variant of an integrative mobile element involving the Xer recombinases, called EcloIMEX-8. The mcr-1-mcr-5 genes were absent from the collection. The isolates belonged to E. cloacae cluster XI, known to be colistin heteroresistant. Here we report the first outbreak of IMI-1-producing Enterobacteriaceae. IMI-1-producers may be underdetected in microbiology laboratories because of their unusual antimicrobial resistance profile (resistant to imipenem but with intermediate resistance to ertapenem and susceptible to extended-spectrum cephalosporins) and the absence of bla IMI-1 in the panel of genes targeted by molecular diagnostic kits., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A multidrug-resistant Klebsiella pneumoniae 1210 isolate with reduced carbapenem susceptibility revealed the presence of a novel plasmid-encoded bla OXA-48-like gene, named bla OXA-519 The 60.7-kb plasmid (pOXA-519) was similar to the IncL-OXA-48 prototypical plasmid except for a ca. 2-kb deletion due to an IS 1R insertion. OXA-519 differed from OXA-48 by a Val120Leu substitution, which resulted in an overall reduced β-lactam-hydrolysis profile, except those for ertapenem and meropenem, which were increased. Thus, detection of OXA-519 producers using biochemical tests that monitor imipenem hydrolysis will be difficult., (Copyright © 2018 American Society for Microbiology.)

For the rapid detection of carbapenemase-producing Enterobacteriaceae (CPE), immunochromatographic lateral flow tests (ICT) have recently been developed. The aim of this study was to assess the new multiplex ICT Resist-3 O.K.N. and to investigate if it can be performed directly from susceptibility testing plates. Additionally, the impact of the inoculum and carbapenem disks on sensitivity and specificity was evaluated. The new ICT was challenged using 63 carbapenem-resistant Enterobacteriaceae (CRE) isolates, including 51 carbapenemase producers. It was assessed under five different conditions directly from Mueller-Hinton agar (MHA): 1 μl or 10 μl of inoculum harvested in the absence of antibiotic pressure or 1 μl taken from the inhibition zone of either an ertapenem, imipenem, or meropenem disk. The sensitivity of the ICT was 100% for OXA-48-like and KPC carbapenemases and 94.4% for the NDM carbapenemase with the 1-μl inoculum. When harvested adjacent to a carbapenem disk, the sensitivity increased to 100%. Additionally, with zinc-supplemented MHA, both the sensitivity increased and the NDM band became visible faster (mean time, 8 ± 3.9 min for MHA compared to 1.9 ± 1.5 min for MHA plus zinc; P = 0.0016). The specificity of the ICT was 100%. The Resist-3 O.K.N. ICT is a sensitive and rapid test for the detection of three highly prevalent carbapenemases. However, false-negative results for NDM can occur. We recommend an inoculum of 1 μl that is harvested adjacent to an ertapenem or meropenem disk and the use of agars with sufficient zinc content to achieve the best performance., (Copyright © 2018 American Society for Microbiology.)

Carbapenem-resistant Enterobacteriaceae are urgent threats to global human health. These organisms produce β-lactamases with carbapenemase activity, such as the metallo-β-lactamase NDM-1, which is notable due to its association with mobile genetic elements and the lack of a clinically useful inhibitor. Here we examined the ability of copper to inhibit the activity of NDM-1 and explored the potential of a copper coordination complex as a mechanism to efficiently deliver copper as an adjuvant in clinical therapeutics. An NDM-positive Escherichia coli isolate, MS6192, was cultured from the urine of a patient with a urinary tract infection. MS6192 was resistant to antibiotics from multiple classes, including diverse β-lactams (penicillins, cephalosporins, and carbapenems), aminoglycosides, and fluoroquinolones. In the presence of copper (range, 0 to 2 mM), however, the susceptibility of MS6192 to the carbapenems ertapenem and meropenem increased markedly. In standard checkerboard assays, copper decreased the MICs of ertapenem and meropenem against MS6192 in a dose-dependent manner, suggesting a synergistic mode of action. To examine the inhibitory effect of copper in the absence of other β-lactamases, the bla NDM-1 gene from MS6192 was cloned and expressed in a recombinant E. coli K-12 strain. Analysis of cell extracts prepared from this strain revealed that copper directly inhibited NDM-1 activity, which was confirmed using purified recombinant NDM-1. Finally, delivery of copper at a low concentration of 10 μM by using the FDA-approved coordination complex copper-pyrithione sensitized MS6192 to ertapenem and meropenem in a synergistic manner. Overall, this work demonstrates the potential use of copper coordination complexes as novel carbapenemase adjuvants., (Copyright © 2018 American Society for Microbiology.)

Klebsiella pneumoniae carbapenemase (KPC) have become a major therapeutic challenge because of its increasingly fast dissemination throughout the world. Accurate detection of KPC is essential for optimal treatment. The Clinical and Laboratory Standards Institutes (CLSI) for fast detection of KPC producers currently recommend Modified Hodge Test (MHT) and Carba NP test. MHT can directly detect carbapenemase production in Enterobacteriaceae isolates. The current study was conducted to evaluate the capacity of MHT with two carbapenem disks for accurate detection of KPC. MHT was performed according to guidelines of CLSI to identify isolates with carbapenem resistance. In doing so, two substrates of MHT were assigned into two groups for examination: meropenem and ertapenem groups. A total of 96 non-repetitive clinical isolates of Klebsiella pneumoniae were tested. The presence of the bla KPC gene in each MHT-positive isolate was examined by PCR. A total of 54 isolates exhibited reduced susceptibility or resistance to carbapenems. Sensitivity of MHT with two carbapenem disks was similar. Specificity of the MHT with meropenem disk was 64% and with ertapenem disk was 53%. Detection of KPC by MHT with meropenem disk was found to be more effective than with ertapenem disk. Based on our results, the presence of KPC does not in itself influence the categorization of resistance. Therefore, the use of MHT with ertapenem disk for the rapid detection of KPC among K. pneumoniae for infection control should not be recommended., (© 2018 Atossa Ghasemnejad et al.)

Introduction: Carbapenems resistance is a growing phenomenon and a threat to public health because of the reduced therapeutic options for resistant infections., Methods: A retrospective case-control study was conducted in 2 tertiary-care hospitals in Medellín, Colombia. Fifty patients infected with ertapenem-resistant enterobacteriaceae were compared with a control group consisting of 100 patients with infections caused by ertapenem susceptible enterobacteriaceae. A multivariate logistic regression model was used to identify factors that best explain ertapenem-resistant enterobacteriaceae infections., Results: The factors associated with ertapenem-resistant enterobacteriaceae infections were prior exposure to carbapenems (adjusted OR 3.43; 95% IC 1.08-10.87) and prior exposure to cefepime (adjusted OR 6.46; 95% IC 1.08-38.38)., Conclusion: Prior exposure to antibiotics is the factor that best explains the ertapenem-resistant enterobacteriaceae infection in this population, highlighting the importance of antimicrobial stewardship programs in hospitals., (Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)