Search Results (65)

Cefepime-enmetazobactam is a novel β-lactam/β-lactamase inhibitor combination showing good activity against multidrug-resistant (MDR) Gram-negative bacteria producing a variety of β-lactamases. In this systematic review, we aimed to evaluate the available data on resistance to this drug. We performed a thorough search of four databases (Embase, PubMed, Scopus, and Web of Science), as well as backward citation searching, to identify studies containing data on resistance to cefepime-enmetazobactam. The data were extracted and analyzed according to the breakpoints established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Food and Drug Administration (FDA), or the specific breakpoints reported by the authors of the respective studies. Analysis based on the type of lactamases produced by the isolates was also performed. Ten studies reported in vitro susceptibility testing and mechanisms of antimicrobial resistance. The total number of isolates was 15,408. The activity of cefepime-enmetazobactam against β-lactamase-producing isolates was variable. The resistance of the studied extended-spectrum β-lactamase (ESBL)-producing and ampicillin C β-lactamase (AmpC)-producing isolates was low (0–2.8% and 0%, respectively). The resistance was higher among oxacillinase-48 β-lactamase (OXA-48)-producing and Klebsiella pneumoniae carbapenemase (KPC)-producing isolates (3.4–13.2% and 36.7–57.8%, respectively). High resistance was noted among metallo-β-^lactamase (MBL)-producing isolates (reaching 87.5% in one study), especially those producing New Delhi metallo-β-lactamase (NDM) and Verona integron-encoded metallo-β-lactamase (VIM), which had the highest rates of resistance. The high activity of cefepime-enmetazobactam against Enterobacterales and selected lactose non-fermenting Gram-negative pathogens, including ESBL-producing and AmpC-producing isolates, makes it a potential carbapenem-sparing agent. The drug should be used after in vitro antimicrobial susceptibility testing in patients with infections caused by OXA-48, KPC, and MBL-producing isolates. Full article

Background/Objectives. Carbapenemase production is the most diffused carbapenem-resistance mechanism among Enterobacterales, with Klebsiella pneumoniae carbapenemase (KPC), Verona-imipenemase (VIM), New-Delhi metallo-β-lactamase (NDM), imipenemase (IMP), and oxacillinase (OXA-48) being reported as the main types within Europe. Particularly, Southern Italy holds a concerningly high percentage of carbapenemases-producing Enterobacterales diffused among different hospital settings. These strains may colonize critical patients’ gastrointestinal tracts, often causing disseminations and severe complications. Scientific data recently reported carbapenemase variants’ worldwide diffusion and several double-carbapenemases reports. The diagnostic routine needs devices whose detection rates are extended to similar epidemiological conditions, avoiding a lack of specificity and potential negative results. Methods. We planned a retrospective study including carbapenem- and/or ceftazidime/avibactam-resistant Enterobacterales (62) which were tested with the KPC/IMP/NDM/VIM/OXA-48 Combo Test Kit (KINVO, Medomics Medical Technology, Nanjing, Jiangsu, China) based on the lateral flow assay (LFA) method. Results. We compared its results to the phenotypic antimicrobial susceptibility testing (AST) MIC results, obtaining a 100% agreement rate. The LFA kit reported carbapenemases in all the tested strains, also identifying cases of KPC variants and double-carbapenemases production. Conclusions. Our data demonstrated how LFAs may represent a reliable alternative requiring minimum economic and personnel resources along with simple result interpretations. Future studies will be necessary to further investigate the system effectiveness on a larger isolates’ number and a broad carbapenemase variant spectrum. Full article

This systematic review assessed the global epidemiology of metallo-β-lactamase (MBL)-producing Acinetobacter clinical isolates and the associated antimicrobial resistance. A total of 475 relevant articles from the Cochrane Library, Google Scholar, PubMed, Scopus, and Web of Science were identified and screened as potentially eligible articles. Data from 85 articles were extracted for the analysis. Most reports on MBL-producing Acinetobacter clinical isolates originated from Asia [68/85 (80%) studies] and Africa [14/85 (16.5%) studies]. There were also scarce reports from Europe and America. The bla_VIM (in 31 studies), bla_IMP (in 29 studies), and bla_NDM (in 21 studies) genes were the most commonly identified genes. In 22 out of 28 (78.6%) studies with comparable data, the proportions of MBL-producing pathogens detected using phenotypic methods were numerically higher than those using genotypic methods. MBL-producing Acinetobacter isolates showed high resistance (up to 100%) to several antibiotic classes, including carbapenems, cephalosporins, fluoroquinolones, and monobactams. However, they showed low resistance to colistin [ranging from 0% (in six studies) to 14.3% (in one study)] and to tigecycline [0% (in three studies)]. No risk of bias assessment was conducted. The findings emphasize the global spread of MBL-producing Acinetobacter and the need for enhanced antimicrobial stewardship, infection control measures, and surveillance. Full article

New Delhi metallo-β-lactamase (NDM) is an enzyme that can degrade a wide range of β-lactam antibiotics. The widespread dissemination of the bla_NDM gene, which encodes NDM, in animal-derived settings poses a threat to public health security. Live poultry markets represent critical nodes in public health surveillance. However, there is currently limited reporting on the spread of the bla_NDM gene within these markets under the One Health approach. This study investigated the prevalence of the bla_NDM gene in live poultry markets and, by integrating newly sequenced genomes with publicly available database entries, performed an in-depth analysis of its association networks with other genetic elements across species. A total of 233 bla_NDM-positive strains, comprising 218 Escherichia coli strains, 4 Enterobacter cloacae strains, 7 Klebsiella pneumoniae, 2 Klebsiella aerogenes, 1 Providencia rettgeri, and 1 Proteus mirabilis were isolated from two live poultry markets in Jiangsu, China. Among the bla_NDM-positive strains, multiple variants were identified, primarily bla_NDM-5, followed by bla_NDM-1, bla_NDM-13, bla_NDM-27, and bla_NDM-39. The coexistence of bla_NDM-5 and mcr-1 was detected in five E. coli strains. Additionally, we found one E. coli strain in which bla_NDM-5 coexisted with estT and tet(X4), and another E. coli strain where bla_NDM-5 coexisted with estT. Spearman correlation analysis of publicly available genomes revealed that the genetic element preferences of bla_NDM variants vary significantly across species (|R| > 0.3, p < 0.05). The element preferences of E. coli strains carrying bla_NDM-5 are similar to those of Klebsiella pneumoniae harboring bla_NDM-1. In Klebsiella aerogenes, Enterobacter cloacae, and Proteus mirabilis, strains carrying bla_NDM-1, have opposite genetic element preferences when compared with strains harboring bla_NDM-5 or bla_NDM-7. Notably, we report the first evidence of the bla_NDM-1 gene transfer mediated by ISKpn13, ISSpu2, and MITEKpn1. The findings highlight that live poultry markets are important transmission hotspots of AMR and thus require continuous surveillance. Full article

Background/Objectives: The global spread of carbapenemase-producing K. pneumoniae (CPKP) strains represent a severe public health threat due to very limited choice of antibacterial therapy. Cefiderocol, a novel siderophore-cephalosporin, may represent a new therapeutic option but resistance is increasingly being described. Our aim was to investigate in vitro cefiderocol susceptibility among CPKP strains in Hungary and assess correlations between resistance, carbapenemase types, and clonal lineages. Methods: The study was performed on 420 CPKP strains from 34 Hungarian healthcare institutes (HCIs) submitted to the National Reference Laboratory of Antimicrobial Resistance (March 2021 to April 2023). The disk diffusion method (Liofilchem, Via Scozia, Italy) was used for in vitro cefiderocol susceptibility testing (according to EUCAST guidelines). For molecular epidemiologic investigation, we used whole genome sequencing (Illumina MiSeq, 150 bp paired-end) and pulsed-field gel electrophoresis (PFGE). Carbapenemase gene type was determined by multiplex PCR. Statistical analysis was performed in R (v.4.2.0). Results: Dominant high-risk clones (ST147, ST395, ST258) exhibited regional distribution, with ST147/NDM-1 strains showing the highest cefiderocol resistance (75%). Overall resistance was 65%. Carbapenemase gene types occurred as follows: 35 bla_VIM, 53 bla_KPC, 57 bla_OXA-48-like, 153 bla_NDM, and 122 bla_OXA-48-like+bla_NDM. Cefiderocol resistance rates by carbapenemase type were 20%, 44%, 70%, and 75% in the case of bla_VIM, bla_OXA-48-like, bla_KPC, bla_NDM, and bla_OXA-48-like+bla_NDM. Conclusions: The results show a high prevalence of cefiderocol resistance in CPKP in Hungary, with different rates of resistance in different carbapenemase gene-carrying high-risk clones, highlighting the growing challenge in treating these infections. Full article

Background: The alarming increase in carbapenemase-producing Enterobacterales is a matter of grave public health concern. The most ubiquitous carbapenemases, Klebsiella pneumoniae carbapenemase (KPC)-, New Delhi metallo-β-lactamase (NDM)-, and oxacillinase (OXA-48)-like enzymes, belong to the Ambler molecular classes A, B, and D, respectively. KPC- and OXA-48-like enzymes have a serine-based hydrolytic mechanism, while NDMs are metallo-β-lactamases that contain zinc in the active site. For the judicious use of reserve drugs and promoting antimicrobial stewardship, timely detection of carbapenemases is essential. While molecular tools are the gold standard for the detection of these enzymes, many laboratories have limited access to them. This study focused on evaluating in-house tools and commercial phenotypic tests for the detection of OXA-48-, KPC-, and NDM-like enzymes in K. pneumoniae, the predominant extremely drug-resistant pathogen in Oman. Methods: In total, 80 GeneXpert/PCR-confirmed (40 OXA-48 and 20 KPC and NDM each) and 37 whole-genome-sequenced (25 OXA-232 and 6 KPC-2, plus NDM-1 and NDM-5) K. pneumoniae were subjected to screening by temocillin (30 μg disk) (MAST Diagnostica, Germany) and D71C (MASTDISCS^®). Isolates resistant to temocillin (<11 mm) and D71C were subjected to four tests: an in-house tool (OXA-48 disk test) and three commercial phenotypic tests: (i) the MASTDISCS^® Combi (D72C) (MAST Group Ltd., Bootle, UK); (ii) the MASTDISCS^® Combi (D73C) (MAST Group Ltd., UK); and (iii) an immunochromatographic assay (ICT), which is the KPC/IMP/NDM/VIM/OXA-48 Combo test kit (Medomics, China), for the detection of OXA-48-, KPC-, and NDM-like carbapenemases. Results: Temocillin exhibited good sensitivity and specificity (100% and 97.50%) compared to D71C (70% and 100%). Among the confirmatory tests, the in-house OXA-48 disk test had 92.50% sensitivity and 100% specificity, while the commercial MAST DISC tests D72C, D73C, and ICT had 97.50%, 95.00%, and 100% sensitivity and 100%, 91.67%, and 95% specificity, respectively. Conclusions: The temocillin disk test is a good screening tool. With high sensitivity and specificity, ease of performance, short turnaround time, and low cost, we recommend the ICT format for routine diagnostic use. In resource-constrained centers, the OXA-48 disk test is an excellent alternative with high sensitivity and specificity. Full article

Background: Carbapenemase-producing Enterobacterales (CPEs) represent a significant global health threat, particularly in the context of nosocomial infections. The current study constitutes a retrospective epidemiological survey that aimed to provide updated data on the prevalence and characteristics of carbapenemases among carbapenem-resistant Enterobacterales (CREs) in a Greek tertiary hospital in Athens during and after the COVID-19 pandemic. Results: A total of 2021 non-duplicate CPE clinical isolates were detected. A significant increase in the number of carbapenemase-positive Enterobacterales was revealed during the study period (p < 0.05). KPC remained the predominant carbapenemase type through all four years of the survey, representing 40.7%, 39.9%, 53.5%, and 45.7% of the CPE isolates, respectively. However, a rapid transition from VIM to NDM metal-β-lactamase types was revealed, changing the epidemiological image of carbapenemases in the hospital setting. Notably, among the CPEs, antimicrobial resistance rates were significantly raised in the post-COVID-19 period (2022 and 2023) compared to the first study year (2020) for almost all the tested antibiotics, including those characterized as last-resort antibiotics. Methods: CREs were identified and subjected to screening for the five most prevalent carbapenemase genes [Klebsiella pneumoniae carbapenemase (KPC), Verona integron-borne metallo-β-lactamase (VIM), New Delhi metallo-β-lactamase (NDM), imipenemase (IMP), and oxacillin-hydrolyzing (OXA-48)] using a lateral flow immunoassay, and the CREs recovered from blood cultures were analyzed using a FilmArray system. Their clinical and epidemiological characteristics, as well as their antimicrobial susceptibility profiles, were also subjected to analysis Conclusions: Given this alarming situation, which is exacerbated by the limited treatment options, the development of new, effective antimicrobial agents is needed. The continued monitoring of the changing epidemiology of carbapenemases is also imperative in order to undertake rational public health interventions. Full article

Background: For investigating the host response in Acinetobacter baumannii associated pneumonia, we analyzed the host genetic sequences obtained from metagenomic next-generation sequencing (mNGS). Methods: The samples for mNGS were bronchoalveolar lavage fluid (BALF) collected from the lungs of patients infected with A. baumannii and from patients without bacterial infections. BALF samples from patients with pneumonia were collected from the lungs of patients infected with A. baumannii with New Delhi metallo-β-lactamase (NDM, before treatment), A. baumannii with NDM (post-treatment), A. baumannii without resistant genes, and those without bacterial infection. Partek was used for investigating enriched functions and pathways related to the pulmonary host response to pneumonia caused by A. baumannii with NDM infection and A. baumannii without antimicrobial-resistant genes. The STRING was employed for identifying protein interaction pathways related to the pulmonary host response to pneumonia caused by A. baumannii without antimicrobial-resistant genes. Results: In pulmonary host response to pneumonia caused by A. baumannii with NDM, five immune system-related pathways and five pathways related to signal transduction were identified. No significant differences were observed in the immune system and signal transduction pathways in the pulmonary host response to pneumonia caused by A. baumannii without antimicrobial-resistant genes. However, significant differences were noted in the phagosome, ferroptosis, and regulation of the actin cytoskeleton in cellular processes. Conclusions: mNGS provides information not only on pathogen gene expression but also on host gene expression. In this study, we found that pneumonia with A. baumannii carrying the NDM resistance gene triggers stronger immune responses in the lung, while pneumonia with A. baumannii lacking antimicrobial resistance genes is more linked to iron-related pathways. Full article

Background/Objectives: Carbapenem resistance poses a significant health threat. This study reports the first detection and characterization of a novel variant of New Delhi metallo-β-lactamase (bla_NDM-60) in Escherichia coli from the United Arab Emirates (UAE), including its genetic context and relationship to global strains. Methods: NDM-60-producing E. coli was isolated from a rectal swab during routine screening. Characterization involved whole-genome sequencing, antimicrobial susceptibility testing, and comparative genomic analysis with 66 known NDM variants. Core genome analysis was performed against 42 global E. coli strains, including the single other reported NDM-60-positive isolate. Results: The strain demonstrated extensive drug resistance, including resistance to novel β-lactam/β-lactamase inhibitor combinations, notably taniborbactam. NDM-60 differs from the closely related NDM-5 by a single amino acid substitution (Asp202Asn) and two amino acid substitutions (Val88Leu and Met154Leu) compared to NDM-1. NDM-60 is located on a nonconjugative IncX3 plasmid. The strain belongs to sequence type 940 (ST940). Phylogenetic analysis revealed high diversity among the global ST940 strains, which carry a plethora of resistance genes and originated from humans, animals, and the environment from diverse geographic locations. Conclusions: NDM-60 emergence in the UAE represents a significant evolution in carbapenemase diversity. Its presence on a nonconjugative plasmid may limit spread; however, its extensive resistance profile is concerning. Further studies are needed to determine the prevalence, dissemination, and clinical impact of NDM-60. NDM evolution underscores the ongoing challenge in managing antimicrobial resistance and the critical importance of vigilant molecular surveillance. It also highlights the pressing demand to discover new antibiotics to fight resistant bacteria. Full article

Background/Objectives: Carbapenem-resistant Enterobacteriaceae (CRE) are types of bacteria that need urgent attention globally. Active surveillance programs at hospitals are essential for the early identification of CRE carriers and the timely adoption of infection control measures. We aimed to analyze the epidemiology of CRE identified by multiplex RT-PCR in rectal swabs of patients upon admission to high-risk wards and to compare data obtained from both molecular and culture CRE screening. Methods: A total of 2861 rectal swabs, prospectively collected within 12–24 h of admission, underwent molecular screening for identification of K. pneumoniae carbapenemase (KPC), New Delhi metallo-β-lactamase (NDM), Verona integron-mediated metallo-β-lactamase (VIM), imipenemase (IMP), and OXA-48 (Allplex^TM Entero-DR Assay). Only samples that tested positive or invalid underwent culture testing (Agar MacConkey and CHROMID^® CARBA plates, bioMérieux, Craponne, France). Results: A total of 118 out of 2861 (about 4%) were positive for at least one carbapenem-resistant gene by a molecular approach (MA), with KPC, NDM, and VIM having the highest prevalence. Culture testing confirmed the presence of carbapenemase in 89 samples (75.4%), showing a disagreement rate of about 25% between the two methods, which, unfortunately, rises up to 60% for VIM. The dominant bacterial species were K. pneumoniae and E. coli (MALDI-TOF mass spectrometry). Conclusions: Our data underlined the need for the molecular screening of CRE carriers in order to implement active surveillance protocol in critical care settings and to improve infection control measures. Full article

In the ongoing battle against antibiotic-resistant bacteria, New Delhi metallo-β-lactamase-1 (NDM-1) has emerged as a significant therapeutic challenge due to its ability to confer resistance to a broad range of β-lactam antibiotics. This study presents a pharmacophore-based virtual screening, docking, and molecular dynamics simulation approach for the identification of potential inhibitors targeting NDM-1, a critical enzyme associated with antibiotic resistance. Through the generation of a pharmacophore model and subsequent virtual screening of compound libraries, candidate molecules (ZINC29142850 (Z1), ZINC78607001 (Z2), and ZINC94303138 (Z3)) were prioritized based on their similarity to known NDM-1 binder (hydrolyzed oxacillin (0WO)). Molecular docking studies further elucidated the binding modes and affinities of the selected compounds towards the active site of NDM-1. These compounds demonstrated superior binding affinities to the enzyme compared to a control compound (−7.30 kcal/mol), with binding scores of −7.13, −7.92, and −8.10 kcal/mol, respectively. Binding interactions within NDM-1’s active site showed significant interactions with critical residues such as His250, Asn220, and Trp93 for these compounds. Subsequent molecular dynamics simulations were conducted to assess the stability of the ligand–enzyme complexes, showing low root mean square deviation (RMSD) values between 0.5 and 0.7 nm for Z1, Z2, which indicate high stability. Z2’s compactness in principal component analysis (PCA) suggests that it can stabilize particular protein conformations more efficiently. Z2 displays a very cohesive landscape with a notable deep basin, suggesting a very persistent conformational state induced by the ligand, indicating robust binding and perhaps efficient inhibition. Z2 demonstrates the highest binding affinity among the examined compounds with a binding free energy of −25.68 kcal/mol, suggesting that it could offer effective inhibition of NDM-1. This study highlights the efficacy of computational tools in identifying novel antimicrobial agents against resistant bacteria, accelerating drug discovery processes. Full article

Background: Carbapenem-resistant Klebsiella pneumoniae (Cr-Kpn) is becoming a growing public health problem through the failure of adequate treatment. This study’s objectives are to describe the sources of Cr-Kpn in our hospital over 22 months, associating factors with the outcome of Cr-Kpn-positive patients, especially those with NDM+OXA-48-like (New Delhi Metallo-β-Lactamase and oxacillinase-48), and the effectiveness of the treatments used. Methods: A retrospective observational cohort study including all hospitalized patients with Cr-Kpn isolates. We reported data as percentages and identified independent predictors for mortality over hospital time through multivariate analysis. Results: The main type of carbapenemases identified were NDM+OXA-48-like (49.4%). The statistical analysis identified that diabetes and co-infections with the Gram-negative, non-urinary sites of infection were factors of unfavorable evolution. The Cox regression model identified factors associated with a poor outcome: ICU admission (HR of 2.38), previous medical wards transition (HR of 4.69), and carbapenemase type NDM (HR of 5.98). We did not find the superiority of an antibiotic regimen, especially in the case of NDM+OXA-48-like. Conclusions: The increase in the incidence of Cr-Kpn infections, especially with NDM+OXA-48-like pathogens, requires a paradigm shift in both the treatment of infected patients and the control of the spread of these pathogens, which calls for a change in public health policy regarding the use of antibiotics and the pursuit of a One Health approach. Full article

Information regarding Klebsiella aerogenes haboring carbapenemase in Japan is limited. A comprehensive nationwide survey was conducted from September 2014 to December 2022, and 67 non-duplicate strains of carbapenem-resistant K. aerogenes were isolated from 57 healthcare facilities in Japan. Through genetic testing and whole-genome sequencing, six strains were found to possess carbapenemases, including imipenemase (IMP)-1, IMP-6, New Delhi metallo-β-lactamase (NDM)-1, and NDM-5. The strain harboring bla_NDM-5 was the novel strain ST709, which belongs to the clonal complex of the predominant ST4 in China. The novel integron containing bla_IMP-1 featured the oxacillinase-101 gene, which is a previously unreported structure, with an IncN₄ plasmid type. However, integrons found in the strains possessing bla_IMP-6, which were the most commonly identified, matched those reported domestically in Klebsiella pneumoniae, suggesting the prevalence of identical integrons. Transposons containing bla_NDM are similar or identical to the transposon structure of K. aerogenes harboring bla_NDM-5 previously reported in Japan, suggesting that the same type of transposon could have been transmitted to K. aerogenes in Japan. This investigation analyzed mobile genetic elements, such as integrons and transposons, to understand the spread of carbapenemases, highlighting the growing challenge of carbapenem-resistant Enterobacterales in Japan and underscoring the critical need for ongoing surveillance to control these pathogens. Full article

Antimicrobial-resistant (AMR) bacteria pose a significant global health threat, and bacteria that produce New Delhi metallo-β-lactamase (NDM) are particularly concerning due to their resistance to most β-lactam antibiotics, including carbapenems. The emergence and spread of NDM-producing genes in food-producing animals highlight the need for a fast and accurate method for detecting AMR bacteria. We therefore propose a PCR-coupled CRISPR/Cas12a-based fluorescence assay that can detect NDM-producing genes (bla_NDM) in bacteria. Thanks to its designed gRNA, this CRISPR/Cas12a system was able to simultaneously cleave PCR amplicons and ssDNA-FQ reporters, generating fluorescence signals. Our method was found to be highly specific when tested against other foodborne pathogens that do not carry bla_NDM and also demonstrated an excellent capability to distinguish single-nucleotide polymorphism. In the case of bla_NDM-₁ carrying E. coli, the assay performed exceptionally well, with a detection limit of 2.7 × 10⁰ CFU/mL: 100 times better than conventional PCR with gel electrophoresis. Moreover, the developed assay detected AMR bacteria in food samples and exhibited enhanced performance compared to previously published real-time PCR assays. Thus, this novel PCR-coupled CRISPR/Cas12a-based fluorescence assay has considerable potential to improve current approaches to AMR gene detection and thereby contribute to mitigating the global threat of AMR. Full article