The occurrence of colistin resistance has increased rapidly among Enterobacterales around the world. We performed a national survey of plasmid-mediated colistin resistance in human clinical isolates through a retrospective analysis of samples from 2009 to 2017 and a prospective sampling in 2018-2020. The aim of this study was to identify and characterize isolates with mcr genes from various regions of the Czech Republic using whole genome sequencing (WGS). Of all 1932 colistin-resistant isolates analyzed, 73 (3.8%) were positive for mcr genes. Most isolates carried mcr-1 (48/73) and were identified as Escherichia coli (n = 44) and Klebsiella pneumoniae (n = 4) of various sequence types (ST). Twenty-five isolates, including Enterobacter spp. (n = 24) and Citrobacter freundii (n = 1) carrying the mcr-9 gene were detected; three of them (Enterobacter kobei ST54) co-harbored the mcr-4 and mcr-9 genes. Multi-drug resistance phenotype was a common feature of mcr isolates and 14% (10/73) isolates also co-harbored clinically important beta-lactamases, including two isolates with carbapenemases KPC-2 and OXA-48. Phylogenetic analysis of E. coli ST744, the dominant genotype in this study, with the global collection showed Czech isolates belonged to two major clades, one containing isolates from Europe, while the second composed of isolates from diverse geographical areas. The mcr-1 gene was carried by IncX4 (34/73, 47%), IncHI2/ST4 (6/73, 8%) and IncI2 (8/73, 11%) plasmid groups. Small plasmids belonging to the ColE10 group were associated with mcr-4 in three isolates, while mcr-9 was carried by IncHI2/ST1 plasmids (4/73, 5%) or the chromosome (18/73, 25%). We showed an overall low level of occurrence of mcr genes in colistin-resistant bacteria from human clinical samples in the Czech Republic.

• Klíčová slova
• Enterobacterales, antibiotic resistance, human, mcr, plasmids,
• Publikační typ
• časopisecké články MeSH

The resistance to carbapenems is usually mediated by enzymes hydrolyzing β-lactam ring. Recently, an alternative way of the modification of the antibiotic, a β-lactone formation by OXA-48-like enzymes, in some carbapenems was identified. We focused our study on a deep analysis of OXA-48-like-producing Enterobacterales, especially strains showing poor hydrolytic activity. In this study, well characterized 74 isolates of Enterobacterales resistant to carbapenems were used. Carbapenemase activity was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), liquid chromatography/mass spectrometry (LC-MS), Carba-NP test and modified Carbapenem Inactivation Method (mCIM). As meropenem-derived β-lactone possesses the same molecular weight as native meropenem (MW 383.46 g/mol), β-lactonization cannot be directly detected by MALDI-TOF MS. In the spectra, however, the peaks of m/z = 340.5 and 362.5 representing decarboxylated β-lactone and its sodium adduct were detected in 25 out of 35 OXA-48-like producers. In the rest 10 isolates, decarboxylated hydrolytic product (m/z = 358.5) and its sodium adduct (m/z = 380.5) have been detected. The peak of m/z = 362.5 was detected in 3 strains co-producing OXA-48-like and NDM-1 carbapenemases. The respective signal was identified in no strain producing class A or class B carbapenemase alone showing its specificity for OXA-48-like carbapenemases. Using LC-MS, we were able to identify meropenem-derived β-lactone directly according to the different retention time. All strains with a predominant β-lactone production showed negative results of Carba NP test. In this study, we have demonstrated that the strains producing OXA-48-like carbapenemases showing false-negative results using Carba NP test and MALDI-TOF MS preferentially produced meropenem-derived β-lactone. We also identified β-lactone-specific peak in MALDI-TOF MS spectra and demonstrated the ability of LC-MS to detect meropenem-derived β-lactone.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální proteiny * analýza   MeSH
• beta-laktamasy analýza   MeSH
• Enterobacteriaceae * MeSH
• karbapenemy farmakologie   MeSH
• meropenem farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• bakteriální proteiny * MeSH
• beta-laktamasy MeSH
• carbapenemase MeSH Prohlížeč
• karbapenemy MeSH
• meropenem MeSH

In this study, we evaluate the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for rapid detection of carbapenemase activity in Enterobacterales in clinical microbiology laboratories during a multicenter networking validation study. The study was divided into three different stages: "software design," "intercenter evaluation," and "clinical validation." First, a standardized procedure with an online software for data analysis was designed. Carbapenem resistance was detected by measuring imipenem hydrolysis and the results were automatically interpreted using the Clover MS data analysis software (Clover BioSoft, Spain). Second, a series of 74 genotypically characterized Enterobacterales (46 carbapenemase-producers and 28 non carbapenemase-producers) were analyzed in 8 international centers to ensure the reproducibility of the method. Finally, the methodology was evaluated independently in all centers during a 2-month period and results were compared with the reference standard for carbapenemase detection used in each center. The overall agreement rate relative to the reference method for carbapenemase resistance detection in clinical samples was 92.5%. The sensitivity was 93.9% and the specificity, 100%. Results were obtained within 60 min and accuracy ranged from 83.3 to 100% among the different centers. Further, our results demonstrate that MALDI-TOF MS is an outstanding tool for rapid detection of carbapenemase activity in Enterobacterales in clinical microbiology laboratories. The use of a simple in-house procedure with online software allows routine screening of carbapenemases in diagnostics, thereby facilitating early and appropriate antimicrobial therapy.

• Klíčová slova
• MALDI-TOF MS, carbapenemases enzymes, clinical microbiology, imipenem, resistance detection,
• Publikační typ
• časopisecké články MeSH

In the last two decades, microbiology laboratories have radically changed by the introduction of novel technologies, like Next-Generation Sequencing (NGS) and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Nevertheless, emergence of antibiotic-resistant microorganisms represents a global threat of current medicine, being responsible for increasing mortality and health-care direct and indirect costs. In addition, the identification of antibiotic-resistant microorganisms, like OXA-48 carbapenemase-producing Enterobacteriaceae, has been changeling for clinical microbiology laboratories. Even the cost of NGS technology and MALDI-TOF MS equipment is relatively high, both technologies are increasingly used in diagnostic and research protocols. Therefore, the aim of this review is to present applications of these technologies used in clinical microbiology, especially in detection of antibiotic resistance and its surveillance, and to propose a combinatory approach of MALDI-TOF MS and NGS for the investigation of microbial associated infections.

• Klíčová slova
• MLST, NGS, beta-lactamase, carbapenemase, susceptibility testing,
• MeSH
• antibakteriální látky farmakologie   MeSH
• Bacteria klasifikace   účinky léků   genetika   izolace a purifikace   MeSH
• bakteriální infekce diagnóza   mikrobiologie   MeSH
• bakteriální léková rezistence * MeSH
• hmotnostní spektrometrie metody   MeSH
• laboratoře nemocniční MeSH
• lidé MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antibakteriální látky MeSH

Ten Enterobacteriaceae isolates collected in a Czech hospital carried blaKPC-positive plasmids of different sizes (∼30, ∼45, and ∼80 kb). Sequencing revealed three types of plasmids (A to C) with the Tn4401a transposon. Type A plasmids comprised an IncR backbone and a KPC-2-encoding multidrug resistance (MDR) region. Type B plasmids were derivatives of type A plasmids carrying an IncN3-like segment, while type C plasmids were IncP6 plasmids sharing the same KPC-2-encoding MDR region with type A and B plasmids.

• Klíčová slova
• Citrobacter freundii, Illumina sequencing, IncR, ST18, Tn4401a,
• MeSH
• antibakteriální látky terapeutické užití   MeSH
• beta-laktamasy genetika   metabolismus   MeSH
• Citrobacter freundii účinky léků   enzymologie   genetika   izolace a purifikace   MeSH
• enterobakteriální infekce farmakoterapie   epidemiologie   mikrobiologie   MeSH
• Escherichia coli účinky léků   enzymologie   genetika   izolace a purifikace   MeSH
• exprese genu MeSH
• izoenzymy genetika   metabolismus   MeSH
• karbapenemy terapeutické užití   MeSH
• Klebsiella pneumoniae účinky léků   enzymologie   genetika   izolace a purifikace   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• mnohočetná bakteriální léková rezistence genetika   MeSH
• Morganella morganii účinky léků   enzymologie   genetika   izolace a purifikace   MeSH
• nemocnice MeSH
• otevřené čtecí rámce MeSH
• plazmidy chemie   klasifikace   metabolismus   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• transpozibilní elementy DNA MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• antibakteriální látky MeSH
• beta-lactamase KPC-2 MeSH Prohlížeč
• beta-laktamasy MeSH
• izoenzymy MeSH
• karbapenemy MeSH
• transpozibilní elementy DNA MeSH

The aim of this study was to characterize the first cases and outbreaks of OXA-48-like-producing Enterobacteriaceae recovered from hospital settings in the Czech Republic. From 2013 to 2015, 22 Klebsiella pneumoniae isolates, 3 Escherichia coli isolates, and 1 Enterobacter cloacae isolate producing OXA-48-like carbapenemases were isolated from 20 patients. Four of the patients were colonized or infected by two or three different OXA-48-like producers. The K. pneumoniae isolates were classified into nine sequence types (STs), with ST101 being predominant (n = 8). The E. coli isolates were of different STs, while the E. cloacae isolate belonged to ST109. Twenty-four isolates carried blaOXA-48, while two isolates carried blaOXA-181 or blaOXA-232 Almost all isolates (n = 22) carried blaOXA-48-positive plasmids of a similar size (∼60 kb), except the two isolates producing OXA-181 or OXA-232. In an ST45 K. pneumoniae isolate and an ST38 E. coli isolate, S1 nuclease profiling plus hybridization indicated a chromosomal location of blaOXA-48 Sequencing showed that the majority of blaOXA-48-carrying plasmids exhibited high degrees of identity with the pOXA-48-like plasmid pE71T. Additionally, two novel pE71T derivatives, pOXA-48_30715 and pOXA-48_30891, were observed. The blaOXA-181-carrying plasmid was identical to the IncX3 plasmid pOXA181_EC14828, while the blaOXA-232-carrying plasmid was a ColE2-type plasmid, being a novel derivative of pOXA-232. Finally, sequencing data showed that the ST45 K. pneumoniae and ST38 E. coli isolates harbored the IS1R-based composite transposon Tn6237 containing blaOXA-48 integrated into their chromosomes. These findings underlined that the horizontal transfer of pOXA-48-like plasmids has played a major role in the dissemination of blaOXA-48 in the Czech Republic. In combination with the difficulties with their detection, OXA-48 producers constitute an important public threat.

• Klíčová slova
• ColE2-like, IncL, IncX3, Klebsiella pneumoniae, OXA-181, OXA-232, Tn1999.2, Tn1999.5,
• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální chromozomy genetika   MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• beta-laktamasy genetika   metabolismus   MeSH
• Enterobacteriaceae účinky léků   enzymologie   genetika   MeSH
• Escherichia coli účinky léků   enzymologie   genetika   MeSH
• Klebsiella pneumoniae účinky léků   enzymologie   genetika   MeSH
• mikrobiální testy citlivosti MeSH
• plazmidy genetika   MeSH
• přenos genů horizontální genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• antibakteriální látky MeSH
• bakteriální proteiny MeSH
• beta-laktamasy MeSH
• carbapenemase MeSH Prohlížeč

VIM-39, a VIM-1-like metallo-β-lactamase variant (VIM-1 Thr33Ala His224Leu) was identified in a clinical isolate of Klebsiella pneumoniae belonging to sequence type 147. VIM-39 hydrolyzed ampicillin, cephalothin, and imipenem more efficiently than did VIM-1 and VIM-26 (a VIM-1 variant with the His224Leu substitution) because of higher turnover rates.

• MeSH
• ampicilin metabolismus   farmakologie   MeSH
• antibakteriální látky metabolismus   farmakologie   MeSH
• beta-laktamasy genetika   metabolismus   MeSH
• beta-laktamová rezistence genetika   MeSH
• biotransformace MeSH
• cefalothin metabolismus   farmakologie   MeSH
• exprese genu MeSH
• hydrolýza MeSH
• imipenem metabolismus   farmakologie   MeSH
• infekce bakteriemi rodu Klebsiella farmakoterapie   mikrobiologie   MeSH
• izoenzymy genetika   metabolismus   MeSH
• kinetika MeSH
• Klebsiella pneumoniae účinky léků   enzymologie   genetika   izolace a purifikace   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• molekulární sekvence - údaje MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• techniky typizace bakterií MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Řecko MeSH
• Názvy látek
• ampicilin MeSH
• antibakteriální látky MeSH
• beta-laktamasy MeSH
• cefalothin MeSH
• imipenem MeSH
• izoenzymy MeSH
• VIM-1 metallo-beta-lactamase MeSH Prohlížeč

IMP-8 metallo-β-lactamase was identified in Klebsiella pneumoniae sequence type 252 (ST252), isolated in a Portuguese hospital in 2009. blaIMP-8 was the first gene cassette of a novel class 3 integron, In1144, also carrying the blaGES-5, blaBEL-1, and aacA4 cassettes. In1144 was located on a ColE1-like plasmid, pKP-M1144 (12,029 bp), with a replication region of limited nucleotide similarity to those of other RNA-priming plasmids, such as pJHCMW1. In1144 and pKP-M1144 represent an interesting case of evolution of resistance determinants in Gram-negative bacteria.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální proteiny genetika   MeSH
• beta-laktamasy genetika   MeSH
• DNA bakterií genetika   MeSH
• infekce bakteriemi rodu Klebsiella mikrobiologie   MeSH
• karbapenemy farmakologie   MeSH
• Klebsiella pneumoniae účinky léků   genetika   izolace a purifikace   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• mnohočetná bakteriální léková rezistence genetika   MeSH
• molekulární sekvence - údaje MeSH
• plazmidy účinky léků   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Portugalsko MeSH
• Názvy látek
• antibakteriální látky MeSH
• bakteriální proteiny MeSH
• beta-lactamase BEL-1, Klebsiella pneumoniae MeSH Prohlížeč
• beta-lactamase GES-5, Klebsiella pneumoniae MeSH Prohlížeč
• beta-laktamasy MeSH
• carbapenemase MeSH Prohlížeč
• DNA bakterií MeSH
• IMP-8 enzyme MeSH Prohlížeč
• karbapenemy MeSH