Special Issue "ß-Lactamases"

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Antimicrobial Agents and Resistance".

Deadline for manuscript submissions: 31 December 2021.

Special Issue Editors

Dr. Thierry Naas
E-Mail Website
Guest Editor
School of Medicine, University Paris Saclay, Hopital de Bicêtre, Service de Bactériologie, Bâtiment Broca, 3ème étage, 78 rue du Gal Leclerc, 94275 Le Kremlin-Bicêtre, France
Interests: genetics of antibiotic resistance; Gram negatives; ß-lactamases; carbapenemases; diagnostics (biochemical, phenotypical, molecular) and diagnostics of antibiotics resistance genes; NGS; transcriptomics; microbiota
Dr. Rémy A. Bonnin
E-Mail Website
Guest Editor
Team Resist, UMR-1184 (INSERM - Université Paris-Saclay - CEA), LabEx Lermit, Faculty of Medicine, Le Kremlin-Bicêtre, France
Interests: carbapenemase producing Enterobacterales; Epidemiology and genomics of Acinetobacter spp.; colistin resistance; mobile genetic elements
Special Issues and Collections in MDPI journals
Dr. Laura Dabos
E-Mail Website
Guest Editor
Evolutionary Systems Genetics of Microbes Lab, Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain
Interests: microbiology; PCR; gel electrophoresis; cloning

Special Issue Information

Dear Colleagues,

The discovery of antibiotics has revolutionized medicine by enabling efficient treatment of many life-threatening bacterial infections. The fight against bacteria is turning again into one of the greatest challenges faced by our societies, especially with the spread of multidrug-resistant (MDR) bacteria. In some cases, resistance extends to the entire repertoire of available therapeutic agents (the so-called pan-drug-resistant phenotypes), posing a formidable challenge to antimicrobial therapy. This is an extremely worrying situation that brings us back to the pre-antibiotic era and thus threatens many achievements of modern medicine that rely on antibiotic therapies.

β-lactams are among the most prescribed antibiotics worldwide, mainly due to their weak toxicity and good efficacy. However, their clinical use is currently threatened by the worldwide spread of β-lactamases (BLs) capable of hydrolyzing them, especially among MDR Gram-negative bacteria (GNB). As the incidence of GNB infections for which few effective treatments are available increases, so does the contribution of drug-hydrolyzing enzymes, the β-lactamases to this serious clinical problem. Currently, β-lactamase-mediated resistance does not spare even the newest and most powerful β-lactams (carbapenems), whose activity is challenged by the class B metallo-β-lactamases (MBLs) (e.g. IMP, VIM, NDM) and the classes A and D serine-carbapenemases (e.g., KPC, IMI, GES, OXA-48, OXA-23, OXA-40).

The number of ß-lactamases described has drastically increased (BLDB reference). They are either point mutant derivatives of well-known enzymes that may lead to modified hydrolysis profiles or to novel enzymes, rarely described in human samples, but may become a future problem. This large heterogeneity of enzymes illustrates the formidable potential of bacteria to adapt themselves to hostile environments and to fight against antibiotics.

This Special Issue is dedicated to all aspects of ß-lactamase research with special emphasis on:

  • Their presence in different compartments (human, veterinarian and environmental samples);
  • Structure–function analysis;
  • Epidemiology;
  • Genetic basis at the origin of their dispersion (Mobile genetic elements and plasmids);
  • The origin of ß-lactamase genes;
  • Unknown ß-lactamases present in metagenomic samples;
  • Novel drugs resistant to beta-lactamase hydrolysis and inhibitors.

Dr. Thierry Naas
Assoc. Prof. Rémy A. Bonnin
Dr. Laura Dobos
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (8 papers)

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Research

Article
Whole-Genome Sequencing (WGS) of Carbapenem-Resistant K. pneumoniae Isolated in Long-Term Care Facilities in the Northern Italian Region
Microorganisms 2021, 9(9), 1985; https://doi.org/10.3390/microorganisms9091985 - 17 Sep 2021
Viewed by 469
Abstract
K. pneumoniae (KPN) is one of the widest spread bacteria in which combined resistance to several antimicrobial groups is frequent. The most common β-lactamases found in K. pneumoniae are class A carbapenemases, both chromosomal-encoded (i.e., NMCA, IMI-1) and plasmid-encoded (i.e., GES-enzymes, IMI-2), VIM, [...] Read more.
K. pneumoniae (KPN) is one of the widest spread bacteria in which combined resistance to several antimicrobial groups is frequent. The most common β-lactamases found in K. pneumoniae are class A carbapenemases, both chromosomal-encoded (i.e., NMCA, IMI-1) and plasmid-encoded (i.e., GES-enzymes, IMI-2), VIM, IMP, NDM, OXA-48, and extended-spectrum β-lactamases (ESBLs) such as CTX-M enzymes. In the present study, a total of 68 carbapenem-resistant KPN were collected from twelve long-term care facilities (LTCFs) in the Northern Italian region. The whole-genome sequencing (WGS) of each KPN strain was determined using a MiSeq Illumina sequencing platform and analysed by a bacterial analysis pipeline (BAP) tool. The WGS analysis showed the prevalence of ST307, ST512, and ST37 as major lineages diffused among the twelve LTCFs. The other lineages found were: ST11, ST16, ST35, ST253, ST273, ST321, ST416, ST1519, ST2623, and ST3227. The blaKPC-2, blaKPC-3, blaKPC-9, blaSHV-11, blaSHV-28, blaCTX-M-15, blaOXA-1, blaOXA-9, blaOXA-23, qnrS1, qnrB19, qnrB66, aac(6′)-Ib-cr, and fosA were the resistance genes widespread in most LTCFs. In this study, we demonstrated the spreading of thirteen KPN lineages among the LTCFs. Additionally, KPC carbapenemases are the most widespread β-lactamase. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Article
Characterization of ESBL-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Clinical Samples in a Northern Portuguese Hospital: Predominance of CTX-M-15 and High Genetic Diversity
Microorganisms 2021, 9(9), 1914; https://doi.org/10.3390/microorganisms9091914 - 09 Sep 2021
Viewed by 422
Abstract
Background: Enterobacteriaceae are major players in the spread of resistance to β-lactam antibiotics through the action of CTX-M β-lactamases. We aimed to analyze the diversity and genetic characteristics of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates from patients in a Northern Portuguese hospital. [...] Read more.
Background: Enterobacteriaceae are major players in the spread of resistance to β-lactam antibiotics through the action of CTX-M β-lactamases. We aimed to analyze the diversity and genetic characteristics of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates from patients in a Northern Portuguese hospital. Methods: A total of 62 cefotaxime/ceftazidime-resistant E. coli (n = 38) and K. pneumoniae (n = 24) clinical isolates were studied. Identification was performed by MALDI-TOF MS. Antimicrobial susceptibility testing against 13 antibiotics was performed. Detection of ESBL-encoding genes and other resistance genes, phylogenetic grouping, and molecular typing (for selected isolates) was carried out by PCR/sequencing. Results: ESBL activity was detected in all 62 E. coli and K. pneumoniae isolates. Most of the ESBL-producing E. coli isolates carried a blaCTX-M gene (37/38 isolates), being blaCTX-M-15 predominant (n = 32), although blaCTX-M-27 (n = 1) and blaCTX-M-1 (n = 1) were also detected. Two E. coli isolates carried the blaKPC2/3 gene. The lineages ST131-B2 and ST410-A were detected among the ESBL-producing blood E. coli isolates. Regarding the 24 ESBL-producing K. pneumoniae isolates, 18 carried a blaCTX-M gene (blaCTX-M-15, 16 isolates; blaCTX-M-55, 2 isolates). All K. pneumoniae isolates carried blaSHV genes, including ESBL-variants (blaSHV-12 and blaSHV-27, 14 isolates) or non-ESBL-variants (blaSHV-11 and blaSHV-28, 10 isolates); ten K. pneumoniae isolates also carried the blaKPC2/3 gene and showed imipenem-resistance. ESBL-positive E. coli isolates were ascribed to the B2 phylogenetic group (82%), mostly associated with ST131 lineage and, at a lower rate, to ST410/A. Regarding K. pneumoniae, the three international lineages ST15, ST147, and ST280 were detected among selected isolates. Conclusions: Different ESBL variants of CTX-M (especially CTX-M-15) and SHV-type (specially SHV-12) were detected among CTX/CAZRE. coli and K. pneumoniae isolates, in occasions associated with carbapenemase genes (blaKPC2/3 gene). Full article
(This article belongs to the Special Issue ß-Lactamases)
Article
OXA-900, a Novel OXA Sub-Family Carbapenemase Identified in Citrobacter freundii, Evades Detection by Commercial Molecular Diagnostics Tests
Microorganisms 2021, 9(9), 1898; https://doi.org/10.3390/microorganisms9091898 - 07 Sep 2021
Viewed by 404
Abstract
Using whole-genome sequencing and cloning of the target gene, we identified blaOXA-900 carbapenemase, a novel blaOXA belonging to a distant and distinct sub-family of blaOXA-48-like. The plasmid-mediated gene was identified in a C. freundii isolate with elevated carbapenem MICs [...] Read more.
Using whole-genome sequencing and cloning of the target gene, we identified blaOXA-900 carbapenemase, a novel blaOXA belonging to a distant and distinct sub-family of blaOXA-48-like. The plasmid-mediated gene was identified in a C. freundii isolate with elevated carbapenem MICs that evaded detection by commercial DNA-based methods. The novel gene, an OXA-48 family carbapenem-hydrolyzing class D β-lactamase, OXA-900, likely originates from marine environmental Shewanella. Since this plasmid-mediated gene has entered a member of the Enterobacterales and evades detection by commonly used tests, it may gain wide dissemination among Enterobacterales. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Article
Assessment of Phenotype Relevant Amino Acid Residues in TEM-β-Lactamases by Mathematical Modelling and Experimental Approval
Microorganisms 2021, 9(8), 1726; https://doi.org/10.3390/microorganisms9081726 - 13 Aug 2021
Viewed by 513
Abstract
Single substitutions or combinations of them alter the hydrolytic activity towards specific β-lactam-antibiotics and β-lactamase inhibitors of TEM-β-lactamases. The sequences and phenotypic classification of allelic TEM variants, as provided by the NCBI National Database of Antibiotic Resistant Organisms, does not attribute phenotypes to [...] Read more.
Single substitutions or combinations of them alter the hydrolytic activity towards specific β-lactam-antibiotics and β-lactamase inhibitors of TEM-β-lactamases. The sequences and phenotypic classification of allelic TEM variants, as provided by the NCBI National Database of Antibiotic Resistant Organisms, does not attribute phenotypes to all variants. Some entries are doubtful as the data assessment differs strongly between the studies or no data on the methodology are provided at all. This complicates mathematical and bioinformatic predictions of phenotypes that rely on the database. The present work aimed to prove the role of specific substitutions on the resistance phenotype of TEM variants in, to our knowledge, the most extensive mutagenesis study. In parallel, the predictive power of extrapolation algorithms was assessed. Most well-known substitutions with direct impact on the phenotype could be reproduced, both mathematically and experimentally. Most discrepancies were found for supportive substitutions, where some resulted in antagonistic effects in contrast to previously described synergism. The mathematical modelling proved to predict the strongest phenotype-relevant substitutions accurately but showed difficulties in identifying less prevalent but still phenotype transforming ones. In general, mutations increasing cephalosporin resistance resulted in increased sensitivity to β-lactamase inhibitors and vice versa. Combining substitutions related to cephalosporin and β-lactamase inhibitor resistance in almost all cases increased BLI susceptibility, indicating the rarity of the combined phenotype. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Article
Targeted Molecular Detection of Nosocomial Carbapenemase-Producing Gram-Negative Bacteria—On Near- and Distant-Patient Surfaces
Microorganisms 2021, 9(6), 1190; https://doi.org/10.3390/microorganisms9061190 - 31 May 2021
Viewed by 809
Abstract
Background: Here, we describe an integrative method to detect carbapenemase-producing Gram-negative bacteria (gn-Cp) on surfaces/fomites in the patient environment. We examined environmental samples from 28 patient rooms occupied with patients who were proven to be colonised with gn-Cp by rectal screening. Methods: We [...] Read more.
Background: Here, we describe an integrative method to detect carbapenemase-producing Gram-negative bacteria (gn-Cp) on surfaces/fomites in the patient environment. We examined environmental samples from 28 patient rooms occupied with patients who were proven to be colonised with gn-Cp by rectal screening. Methods: We took samples after 24 h, 72 h and one week. For sampling, we divided the patient environment into four parts and took samples from near- and extended patient areas. To obtain a representative bacterial swab from a larger surface, such as the patient cabinet, we used Polywipes. Bacterial DNA was isolated. Carbapenemase was detected with specific qPCR primers. Results: With this culture- and molecular-based approach, we could control the effectiveness of cleaning and disinfection in everyday clinical practice. Therefore, we could track the spread of gn-Cp within the patient room. The number of positive detections fluctuated between 30.5% (mean value positive results after 72 h) and 35.2% (after 24 h and one week). Conclusion: The method used to detect multidrug-resistant bacteria in the environment of patients by using PolywipesTM is reliable and can therefore be used as an effective, new tool in hygiene and infection control. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Article
Molecular Characterization of Antimicrobial Resistance and Virulence Genes of Bacterial Pathogens from Bovine and Caprine Mastitis in Northern Lebanon
Microorganisms 2021, 9(6), 1148; https://doi.org/10.3390/microorganisms9061148 - 27 May 2021
Viewed by 1169
Abstract
Mastitis is an infectious disease encountered in dairy animals worldwide that is currently a growing concern in Lebanon. This study aimed at investigating the etiology of the main mastitis-causing pathogens in Northern Lebanon, determining their antimicrobial susceptibility profiles, and identifying their antimicrobial resistance [...] Read more.
Mastitis is an infectious disease encountered in dairy animals worldwide that is currently a growing concern in Lebanon. This study aimed at investigating the etiology of the main mastitis-causing pathogens in Northern Lebanon, determining their antimicrobial susceptibility profiles, and identifying their antimicrobial resistance (AMR) genes. A total of 101 quarter milk samples were collected from 77 cows and 11 goats presenting symptoms of mastitis on 45 dairy farms. Bacterial identification was carried out through matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibility was tested by disc diffusion and broth microdilution methods. Molecular characterization included polymerase chain reaction (PCR) screening for genes encoding extended-spectrum beta-lactamases (ESBLs) and plasmid-mediated AmpC among Enterobacterales isolates, and virulence factors among Staphylococcus isolates. Escherichia coli isolates were subjected to phylogenetic typing by a quadruplex PCR method. The most frequently identified species were Streptococcus uberis (19.2%), Streptococcus agalactiae (15.1%), E. coli (12.3%), and Staphylococcus aureus (10.96%). Gram-positive bacteria were resistant to macrolides and tetracycline, whereas gram-negative bacteria displayed resistance to ampicillin and tetracycline. Two ESBL genes, blaTEM (83.3%) and blaOXA (16.7%), and one AmpC beta-lactamase gene, blaCMY-II (16.7%), were detected among six E. coli isolates, which mainly belonged to phylogenetic group B1. Among Staphylococcus spp., the mecA gene was present in three isolates. Furthermore, four isolates contained at least one toxin gene, and all S. aureus isolates carried the ica operon. These findings revealed the alarming risk of AMR in the Lebanese dairy chain and the importance of monitoring antimicrobial usage. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Article
Identity of blaCTX-M Carrying Plasmids in Sequential ESBL-E. coli Isolates from Patients with Recurrent Urinary Tract Infections
Microorganisms 2021, 9(6), 1138; https://doi.org/10.3390/microorganisms9061138 - 25 May 2021
Cited by 2 | Viewed by 744
Abstract
Plasmid-mediated multidrug resistance in E. coli is becoming increasingly prevalent. Considering this global threat to human health, it is important to understand how plasmid-mediated resistance spreads. From a cohort of 123 patients with recurrent urinary tract infections (RUTI) due to extended spectrum beta-lactamase [...] Read more.
Plasmid-mediated multidrug resistance in E. coli is becoming increasingly prevalent. Considering this global threat to human health, it is important to understand how plasmid-mediated resistance spreads. From a cohort of 123 patients with recurrent urinary tract infections (RUTI) due to extended spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli), only five events with a change of ESBL E. coli strain between RUTI episodes were identified. Their blaCTX-M encoding plasmids were compared within each pair of isolates using optical DNA mapping (ODM) and PCR-based replicon typing. Despite similar blaCTX-M genes and replicon types, ODM detected only one case with identical plasmids in the sequential ESBL E. coli strains, indicating that plasmid transfer could have occurred. For comparison, plasmids from seven patients with the same ESBL E. coli strain reoccurring in both episodes were analyzed. These plasmids (encoding blaCTX-M-3, blaCTX-M-14, and blaCTX-M-15) were unaltered for up to six months between recurrent infections. Thus, transmission of blaCTX-M plasmids appears to be a rare event during the course of RUTI. Despite the limited number (n = 23) of plasmids investigated, similar blaCTX-M-15 plasmids in unrelated isolates from different patients were detected, suggesting that some successful plasmids could be associated with specific strains, or are more easily transmitted. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Article
Presence of Broad-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in Zoo Mammals
Microorganisms 2021, 9(4), 834; https://doi.org/10.3390/microorganisms9040834 - 14 Apr 2021
Cited by 1 | Viewed by 540
Abstract
Broad-spectrum beta-lactamase (BSBL)-producing Enterobacteriaceae impose public health threats. With increased popularity of zoos, exotic animals are brought in close proximity of humans, making them important BSBL reservoirs. However, not much is known on the presence of BSBLs in zoos in Western Europe. Fecal [...] Read more.
Broad-spectrum beta-lactamase (BSBL)-producing Enterobacteriaceae impose public health threats. With increased popularity of zoos, exotic animals are brought in close proximity of humans, making them important BSBL reservoirs. However, not much is known on the presence of BSBLs in zoos in Western Europe. Fecal carriage of BSBL-producing Enterobacteriaceae was investigated in 38 zoo mammals from two Belgian zoos. Presence of bla-genes was investigated using PCR, followed by whole-genome sequencing and Fourier-transform infrared spectroscopy to cluster acquired resistance encoding genes and clonality of BSBL-producing isolates. Thirty-five putatively ceftiofur-resistant isolates were obtained from 52.6% of the zoo mammals. Most isolates were identified as E. coli (25/35), of which 64.0% showed multidrug resistance (MDR). Most frequently detected bla-genes were CTX-M-1 (17/25) and TEM-1 (4/25). Phylogenetic trees confirmed clustering of almost all E. coli isolates obtained from the same animal species. Clustering of five isolates from an Amur tiger, an Amur leopard, and a spectacled bear was observed in Zoo 1, as well as for five isolates from a spotted hyena and an African lion in Zoo 2. This might indicate clonal expansion of an E. coli strain in both zoos. In conclusion, MDR BSBL-producing bacteria were shown to be present in the fecal microbiota of zoo mammals in two zoos in Belgium. Further research is necessary to investigate if these bacteria pose zoonotic and health risks. Full article
(This article belongs to the Special Issue ß-Lactamases)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

1. Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolated from clinical samples in a northern Portuguese hospital: predominance of CTX-M-15 and high genetic diversity

Abstract: Background: Enterobacteriaceae are major players in the spread of resistance to β-lactam antibiotics through the action of CTX-M β-lactamases. We aimed to analyze the diversity and genetic characteristics of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates from patients in a northern Portuguese hospital. Methods: A total of 62 cefotaxime/ceftazidime-resistant E. coli (n=38) and K. pneumoniae (n=24) clinical isolates were studied. Identification was performed by MALDI-TOF MS. Antimicrobial susceptibility testing against 13 antibiotics was performed. Detection of ESBL encoding resistance genes, phylogenetic grouping, and molecular typing (for selected isolates) was carried out by PCR/sequencing. Results: ESBL activity was detected in all 62 E. coli and K. pneumoniae isolates. Most of the ESBL-producing E. coli isolates carried a blaCTX-M gene (37/38 isolates), being blaCTX-M-15 predominant (n=32), although blaCTX-M-27 (n=1) and blaCTX-M-1 (n=1) were also detected. Two E. coli isolates carried the blaKPC2/3 gene. Regarding the 24 ESBL-producing K. pneumoniae isolates, 18 carried a blaCTX-M gene (blaCTX-M-15, 16 isolates; blaCTX-M-55, 2 isolates). All K. pneumoniae isolates carried blaSHV genes, including ESBL-variants (blaSHV-12, blaSHV-27, 14 isolates) or non-ESBL-variants (blaSHV-11, blaSHV-28, 10 isolates); Ten K. pneumoniae isolates also carried the blaKPC2/3 gene and showed imipenem-resistance. ESBL-positive E. coli isolates were ascribed to the B2 phylogenetic group (82%), mostly associated with ST131 lineage and, at a lower rate, to ST410/A. Regarding K. pneumoniae, the three international lineages ST15, ST147, and ST280 were detected among selected isolates. Conclusions: Different ESBL variants of CTX-M (especially CTX-M-15) and SHV-type (specially SHV-12) were detected among CTX/CAZR E. coli and K. pneumoniae isolates, in occasions associated with carbapenemases (blaKPC2/3 gene). 
Keywords: Antimicrobial resistance, Klebsiella pneumoniae, Escherichia coli, Public health, Car-bapenemases, β-lactamases, KPC2/3, CTX-M-15, human, Portugal
2. Title: CTX-M carrying plasmid identity in sequential E. coli isolates from patients with recurrent urinary tract infections.
Short summery: blaCTX-M (-14, -15 and -27)-carrying plasmids in various ESBL-E coli from patients with recurrent urinary tract infections (UTI) were analyzed for identity in 2-3 sequential isolates/patient using a new method, optical DNA-mapping combined with CRISPR/Cas9 (PMID: 27905467). Plasmids were strikingly identical in sequential ESBL-E coli isolated up to 6 months apart. Possible plasmid transfer between sequential ESBL-E.coli UTI-isolates was seen occasionally but appear to be very rare.  

3. A comprehensive review on betalactamases and their role outside bacteria (archae, humans, viruses..)
4. An original article on betalactamases characterization in CPR
5. by Guest editors
6. by Guest editors
7. Old antibiotics are one more treatment option for bacterial infections
8.
A mathematical and mutational genotype-phenotype analysis of TEM-beta-lactamase
Abstract: The TEM β-lactamase (BLs) are widespread in clinical isolates often conferring resistance to cephalosporins and β-lactamase-inhibitors
(BLI), which are the mainstay of empiric therapy for infections by gram-negative bacteria. Single amino acid substitutions, so far not
addressed by molecular diagnostics, can dramatically change the phenotype of TEMs.Applying mathematical modelling, we aimed to
identify amino acid positions of diagnostic relevance, which were proofed by targeted mutagenesis and comprehensive testing of the MIC against broad panel of substrates and inhibitors. Twelve amino acid positions were identified as good candidates for molecular differentiation of the phenotype. In double-mutants, where ESBL- and BLI-resistance-related positions were combined, the ESBL phenotype manifested. A different phenotype was observed for some TEM alleles compared to the reference database.
 9.Targeted molecular detection of nosocomial carbapenemase-producing gram-negative bacteria – on near- and distant-patient surfaces
Abstract: Background: Here, we describe an integrative method to detect
carbapenemase-producing gram-negative bacteria (gn-Cp) on
surfaces/fomites in the patient environment. For sampling, we
examined patient rooms from different wards of a 1400-bed university
hospital in Germany. From December 2018 to June 2020, we examined
environmental samples from 28 patient rooms occupied with patients
who were proven to be colonized with gn-Cp by rectal screening.

Methods:Depending on the duration of the patient’s hospitalization, we took
samples after 24 hours, 72 hours and one week. For sampling, we
divided the patients´ environment into four parts and took samples
from near- and extended patient areas. To obtain a representative
bacterial swab from a larger surface, such as the patient cabinet,
we used PolywipesTM (medical wire, Corsham, Wiltshire, UK). To
enrich the bacteria within the wipe, we used CASO boullion (Merck
KGaA, Germany). The bacterial DNA was isolated. Carbapenemase was
detected with specific qPCR primers.

Results :With this culture- and molecular-based approach, we could control
the effectiveness of cleaning and disinfection in everyday clinical
practice. Therefore, we could track the spread of gn-Cp within the
patient room. The number of positive detections fluctuated between
30.5 % (mean value positive results after 72 hours) and 35.2 %
(after 24 hours and one week).

Conclusion:The method used to detect multidrug-resistant bacteria in the
environment of patients by using PolywipesTM is reliable and can
therefore be used as an effective, new tool in hygiene and infection
control.



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