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The Enterobacter cloacae complex (ECC) is highly diverse; its many species and subspecies can be distinguished by using phenotypic methods or matrix-assisted laser desorption/ionization time-offlight mass spectrometry. Whole-genome sequencing enables [...]

Few last-line antimicrobial agents effectively treat infections caused by New Delhi metallo-[beta]-lactamase (NDM)-producing Enterobacterales (1). Cefiderocol is a novel synthetic conjugate siderophore cephalosporin that is more stable against [beta]-lactamase hydrolysis [...]

The massive dissemination of carbapenemase-producing Enterobacterales poses a global threat to public health. Carbapenem antibiotics remain the last line of defense against highly resistant Enterobacterales. Carbapenemases have been identified in [...]

Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has spread globally and strained health systems with an exponentially increasing number of acute respiratory failures (1). Because severe cases of respiratory distress [...]

OXA-244, an R214G variant of OXA-48, is silently spreading worldwide likely because of difficulties in detection using classical screening media. Here, we characterized two clinical isolates of Escherichia coli and Citrobacter youngae that displayed reduced susceptibility to carbapenems but were lacking significant carbapenemase activity as revealed by negative Carba NP test results. However, positive test results were seen for OXA-48-like enzymes by lateral flow immunoassays. WGS revealed the presence of a blaOXA-181-like gene that codes for OXA-484, an R214G variant of OXA-181. BlaOXA-484 gene was located on a 58.4-kb IncP1-like plasmid (pN-OXA-484), that upon transfer into E. coli HB4 with impaired permeability, conferred carbapenem and temocillin resistance (MICs > 32 mg/L). E. coli TOP10 (pTOPO-OXA-484) revealed reduced MICs in most substrates as compared to E. coli TOP10 (pTOPO-OXA-181), especially for imipenem (0.25 mg/L versus 0.75 mg/L) and temocillin (16 mg/L versus 1028 mg/L). Catalytic efficiencies of OXA-484 were reduced as compared to OXA-181 for most ß-lactams including imipenem and temocillin with 27.5- and 21.7-fold reduction, respectively. Molecular modeling confirmed that the salt bridges between R214, D159, and the R1 substituent's carboxylate group of temocillin were not possible with G214 in OXA-484, explaining the reduced affinity for temocillin. In addition, changes in active site's water network may explain the decrease in hydrolysis rate of carbapenems. OXA-484 has weak imipenem and temocillin hydrolytic activities, which may lead to silent spread due to underdetection using selective screening media or biochemical imipenem hydrolysis confirmatory tests. [ABSTRACT FROM AUTHOR]

Background Carbapenem-resistant Pseudomonas aeruginosa are being increasingly described worldwide. Here, we investigated the molecular mechanisms underlying carbapenem resistance in an extremely drug-resistant P. aeruginosa isolate from a neonatal intensive care unit in Morocco. Materials and methods P. aeruginosa strain O82J1 was identified using MALDI-TOF-MS. Carba NP, immunochromatographic assay NG Carba5 and antimicrobial susceptibility testing using disc diffusion and microbroth were performed. Whole-genome sequencing using the Illumina and MinION technologies and different software packages available at the Center of Genomic Epidemiology were used to predict the resistome, sequence type and plasmid types. Results P. aeruginosa O82J1 co-expressed two metallo-β-lactamases, bla NDM-1 and bla VIM-2, and was susceptible to colistin and apramycin only. It belonged to ST773 that is frequently reported worldwide as a high-risk P. aeruginosa clone. The bla VIM-2 gene was integron-borne on a IncP-2 465-kb plasmid, whereas the bla NDM-1 gene was chromosomally encoded and embedded in an integrative conjugative element, probably at the origin of its acquisition. A total of 23 antimicrobial resistance genes were detected including a bla PER-1 ESBL gene, and an 16S-rRNA methyltransferase gene rmtB. Conclusions The isolation of XDR P. aeruginosa isolates expressing several carbapenemases in a neonatal intensive care unit is of great concern due to the reduced treatment options, relying only on colistin, but not recommended in neonates, and apramycin, not yet approved for human therapy. Concerns were further elevated due to the resistance to cefiderocol and ATM/AVI, two novel and last-resort antibiotics recommended to treat infections caused by Gram-negative bacteria, particularly XDR P. aeruginosa in adults. [ABSTRACT FROM AUTHOR]

Carbapenems are the last line antimicrobial drugs for treating infections caused by multidrug-resistant Enterobacterales. The global dissemination of carbapenemase-producing Enterobacterales (CPE; formerly known as carbapenemase-producing Enterobacteriaceae) pose a serious threat [...]

Background VRE are increasingly described worldwide. Screening of hospitalized patients at risk for VRE carriage is mandatory to control their dissemination. Here, we have developed the Bfast [VRE Panel] PCR kit, a rapid and reliable quantitative PCR assay for detection of vanA , vanB , vanD and vanM genes, from solid and liquid cultures adaptable to classical and ultrafast real-time PCR platforms. Methods Validation was carried out on 133 well characterized bacterial strains, including 108 enterococci of which 64 were VRE. Analytical performances were determined on the CFX96 Touch (Bio-Rad) and Chronos Dx (BforCure), an ultrafast qPCR machine. Widely used culture plates and broths for enterococci selection/growth were tested. Results All targeted van alleles (A, B, D and M) were correctly detected without cross-reactivity with other van genes (C, E, G, L and N) and no interference with the different routinely used culture media. A specificity and sensitivity of 100% and 99.7%, respectively, were determined, with limits of detection ranging from 21 to 238 cfu/reaction depending on the targets. The Bfast [VRE Panel] PCR kit worked equally well on the CFX and Chronos Dx platforms, with differences in multiplexing capacities (five and four optical channels, respectively) and in turnaround time (45 and 16 minutes, respectively). Conclusions The Bfast [VRE Panel] PCR kit is robust, easy to use, rapid and easily implementable in clinical microbiology laboratories for ultra-rapid confirmation of the four main acquired van genes. Its features, especially on Chronos Dx, seem to be unmatched compared to other tools for screening of VRE. [ABSTRACT FROM AUTHOR]

In Klebsiella pneumoniae bacteria, resistance to carbapenems results in 2 main mechanisms: the production of an extended spectrum [beta]-lactamase or plasmid-borne cephalosporinase associated with a decrease in permeability of the [...]

Abscesses represent the most prominent emerging problem in the red meat industry, leading to great economic constraints and public health hazards. Data on etiological agents present in these purulent lesions in Algeria are very scarce. The aim of this study was to identify the bacteria responsible for these abscesses and to determine their antibiotic susceptibility profiles. A total of 123 samples of abscesses from 100 slaughtered sheep and 23 slaughtered cattle were cultured in several media. A total of 114 bacterial isolates were cultured from 103 abscesses. Bacteria were identified using MALDI–TOF, and antibiotic susceptibility was determined by the disk diffusion method on Mueller–Hinton agar. A total of 73.6% (n = 84) corresponded to Enterobacterales, of which four were multidrug-resistant (MDR). These isolates, together with Staphylococcus aureus, coagulase negative Staphylococci, and seven randomly chosen susceptible Escherichia coli isolates, were further characterized using WGS. Resistome analysis of the four MDR Enterobacterales isolates revealed the presence of OXA-48 carbapenemase in two Klebsiella pneumoniae ST985 and one E. coli ST10 isolates and a CTX-M-15 ESBL in one E. coli isolate ST1706. Two coagulase-negative Staphylococci isolates were found to carry the mecA gene. WGS showed the presence of different resistance genes and virulence genes. Our study revealed 5% of MDR Enterobacterales (including ESBLs and carbapenemases) identified from abscesses, thus urging the need for abscess monitoring in slaughterhouses. [ABSTRACT FROM AUTHOR]

This article discusses a study on antimicrobial resistance (AMR) in Lebanon, specifically focusing on the presence of the blaNDM-5 gene in E. coli isolates. The study found that blaNDM-5-harbouring E. coli ST617 was present in Syrian refugees, their animals, and the camp environment, posing a health risk to both the refugees and the hosting community. The study emphasizes the importance of integrated surveillance programs and One Health studies to address AMR in vulnerable populations and highlights the role of war, mass migration, and displacement in the spread of AMR. Funding for the study was provided by various organizations, and ethical considerations were taken into account. [Extracted from the article]

In Europe, evidence for the spread of extended-spectrum [beta]-lactamase (ESBL)-producing Escherichia coli from animals to humans via food is unclear (1). Few studies have been conducted in low- and middle-income [...]

This article discusses the discovery of the OXA-198 carbapenemase gene cassette in the genus Candidatus Accumulibacter. The Candidatus Accumulibacter genus is known for its role in enhanced biological phosphate removal in wastewater treatment. The OXA-198 gene was first identified in clinical Pseudomonas aeruginosa isolates and later in Enterobacterales. The study found that the blaOXA-198-like gene was present in three different regions of Denmark, but unfortunately, the isolates were not cultivated. The genetic contexts of the blaOXA-198-like genes were analyzed, and it was determined that they were not acquired from other sources. The study suggests that Candidatus Accumulibacter may be the progenitor of OXA-198-like carbapenemase-encoding genes. This finding is significant as it provides insight into the origins of carbapenemase genes and may aid in future research and prevention efforts. [Extracted from the article]

This article discusses the emergence of a multidrug-resistant strain of Enterobacter xiangfangensis (Exn692) in a patient with COVID-19 and diabetes in Lebanon. The strain showed resistance to 37 antibiotics from different classes and carried genes that encoded resistance to these antibiotics. However, it was susceptible to a few antibiotics. The study emphasizes the challenges in treating infections caused by multidrug-resistant bacteria and the importance of effective antimicrobial stewardship. It also highlights the need for monitoring the evolution of Enterobacter xiangfangensis and developing accurate identification tools to understand its epidemiology, pathogenesis, and antibiotic resistance properties. [Extracted from the article]

This article discusses the emergence of carbapenem resistance in Enterobacterales, specifically through the dissemination of carbapenemase-producing bacteria. The study characterizes two new variants of the VIM-1 enzyme, called VIM-29 and VIM-86, which were isolated in multidrug-resistant Enterobacterales in France. The isolates were resistant to all β-lactam antibiotics except aztreonam/avibactam. The study also analyzes the genetic environment of the VIM-29 and VIM-86 genes and identifies common resistance determinants. The plasmids carrying these genes were found to be self-conjugative. The hydrolytic abilities of VIM-29 and VIM-86 were compared to other prevalent VIM variants, and it was found that they displayed similar resistance profiles. The study concludes that these new variants contribute to the growing problem of carbapenem resistance. [Extracted from the article]

Here, we characterized the first French NDM-9-producing Acinetobacter baumannii isolate. A. baumannii 13A297, which belonged to the STPas25 (international clone IC7), was highly resistant to β-lactams including cefiderocol (MIC >32 mg/L). Whole genome sequencing (WGS) using both Illumina and Oxford Nanopore technologies revealed a 166-kb non-conjugative plasmid harboring a blaNDM-9 gene embedded in a Tn125 composite transposon. Complementation of E. coli DH5α and A. baumannii CIP70.10 strains with the pABEC plasmid carrying the blaNDM-1 or blaNDM-9 gene, respectively, resulted in a significant increase in cefiderocol MIC values (16 to >256-fold), particularly in the NDM-9 transformants. Interestingly, steady-state kinetic parameters, measured using purified NDM-1 and NDM-9 (Glu152Lys) enzymes, revealed that the affinity for cefiderocol was 3-fold higher for NDM-9 (Km = 53 μM) than for NDM-1 (Km = 161 μM), leading to a 2-fold increase in catalytic efficiency for NDM-9 (0.13 and 0.069 μM−1 . s−1, for NDM-9 and NDM-1, respectively). Finally, we showed by molecular docking experiments that the residue 152 of NDM-like enzymes plays a key role in cefiderocol binding and resistance, by allowing a strong ionic interaction between the Lys152 residue of NDM-9 with both the Asp223 residue of NDM-9 and the carboxylate group of the R1 substituent of cefiderocol. [ABSTRACT FROM AUTHOR]

The development of novel antibiotics is mandatory to curb the growing antibiotic resistance problem resulting in difficult-to-treat bacterial infections. Here, we have determined the spectrum of activity of cystobactamids and chelocardins, two novel and promising classes of molecules with different modes of action. A panel of 297 clinically relevant Gram-negative and Gram-positive isolates with different antibiotic susceptibility profiles, going from wild type to multi- or even extremely drug resistant (MDR, XDR) and including carbapenem-resistant isolates, were tested using broth microdilution assays to determine the minimal inhibitory concentrations (MICs), MIC50s and MIC90s of two cystobactamids derivatives (CN-861-2 and CN-DM-861) and two chelocardin derivatives (CHD and CDCHD). Cystobactamids revealed potent activities on the majority of tested Enterobacterales (MIC50s ranging from 0.25 to 4 µg/mL), except for Klebsiella pneumoniae isolates (MIC50s is 128 µg/mL). Pseudomonas aeruginosa and Acinetobacter baumannii showed slightly higher MIC50s (4 µg/mL and 8 µg/mL, respectively) for cystobactamids. Chelocardins inhibited the growth of Enterobacterales and Stenotrophomas maltophilia at low to moderate MICs (0.25–16 µg/mL) and the chemically modified CDCHD was active at lower MICs. A. baumannii and P. aeruginosa were less susceptible to these molecules with MICs ranging from 0.5 to 32 µg/mL. These molecules show also interesting in vitro efficacies on clinically relevant Gram-positive bacteria with MICs of 0.125–8 µg/mL for cystobactamids and 0.5–8 µg/mL for chelocardins. Taken together, the cystobactamid CN-DM-861 and chelocardin CDCHD showed interesting antibiotic activities on MDR or XDR bacteria, without cross-resistance to clinically relevant antibiotics such as carbapenems, fluoroquinolones, and colistin. [ABSTRACT FROM AUTHOR]

Background Cefiderocol is a catechol-substituted cephalosporin with potent in vitro activity against carbapenem-resistant (CR) Gram-negative bacteria (GNB). Cefiderocol susceptibility testing is complex because iron concentrations need to be taken into consideration. Here, we assessed the clinical performance of Bruker's UMIC® Cefiderocol and corresponding iron-depleted CAMHB to determine MIC by broth microdilution (BMD) for clinically relevant GNB. Methods MICs of cefiderocol for 283 GN clinical isolates were determined by BMD using iron-depleted CAMHB. Frozen panels were used as a reference. The concentration range of cefiderocol was 0.03–32 mg/L. The isolates, with different degrees of susceptibility to cefiderocol, included Enterobacterales (n  = 180) , Pseudomonas aeruginosa (n  = 49), Acinetobacter baumannii (n  = 44) and Stenotrophomonas maltophilia (n  = 10). Results The rates of categorical agreement (CA), essential agreement (EA) and bias were calculated to evaluate the performance of the UMIC® Cefiderocol, as compared with the reference method. Overall, the UMIC® Cefiderocol showed 90.8% EA (95% CI: 86.9%–93.7%) with a bias of −14.5% and a CA of 90.1% (95% CI: 86.1%–93.1%). For Enterobacterales, the UMIC® Cefiderocol showed 91.7% EA (95% CI: 86.7%–94.9%) with a bias of −25.0% and a CA of 87.8% (95% CI: 82.2%–91.8%). For non-fermenters, the UMIC® Cefiderocol showed 89.3% EA (95% CI: 81.9%–93.9%) (not significantly different from 90.0%, Student t -test) with a bias of −3.9% and a CA of 94.2% (95% CI: 87.7%–97.3%). Conclusions UMIC® Cefiderocol is a valid method for the determination of cefiderocol MICs even if higher than expected discrepancies were observed with NDM-producing Enterobacterales, which presented in most cases MIC values close to the breakpoint. [ABSTRACT FROM AUTHOR]

Background As carbapenemase-producing Enterobacterales are increasingly reported worldwide, their rapid detection is crucial to reduce their spread and prevent infections and outbreaks. Lateral flow immunoassays (LFIAs) have become major tools for the detection of carbapenemases. However, as for most commercially available assays, only the five main carbapenemases are targeted. Objectives Here, we have developed and evaluated an LFIA prototype for the rapid and reliable detection of the increasingly identified GES-type β-lactamases. Methods The GES LFIA was validated on 103 well-characterized Gram-negative isolates expressing various β-lactamases grown on Mueller–Hinton (MH) agar, chromogenic, and chromogenic/selective media. Results The limit of detection of the assay was 106 cfu per test with bacteria grown on MH agar plates. GES LFIA accurately detected GES-type β-lactamases irrespective of the culture media and the bacterial host. The GES LFIA was not able to distinguish between GES-ESBLs and GES-carbapenemases. Because GES enzymes are still rare, their detection as an ESBL or a carbapenemase remains important, especially because extensive use of carbapenems to treat ESBL infections may select for GES variants capable of hydrolysing carbapenems. Conclusions The GES LFIA is efficient, rapid and easy to implement in the routine workflow of a clinical microbiology laboratory for the confirmation of GES-type β-lactamases. Combining it with immunochromatographic assays targeting the five main carbapenemases (KPC, NDM, VIM, IMP and OXA-48) would improve the overall sensitivity for the most frequently encountered carbapenemases and ESBLs, especially in non-fermenters. [ABSTRACT FROM AUTHOR]