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Journal of Clinical Microbiology May 2023Due to limited therapeutic options, there is a clinical need to assess the activity of the combination of aztreonam (ATM) and ceftazidime-avibactam (CZA) to guide the...
Due to limited therapeutic options, there is a clinical need to assess the activity of the combination of aztreonam (ATM) and ceftazidime-avibactam (CZA) to guide the therapeutic management of multidrug-resistant (MDR) Gram-negative organism infections. We set out to develop a practical MIC-based broth disk elution (BDE) method to determine the activity of the combination ATM-CZA using readily available supplies and compare it to reference broth microdilution (BMD). For the BDE method, a 30-μg ATM disk, a 30/20-μg CZA disk, both disks in combination, and no disks were added to 4 separate 5-mL cation-adjusted Mueller-Hinton broth (CA-MHB) tubes, using various manufacturers. Three testing sites performed both BDE and reference BMD testing of bacterial isolates in parallel from a single 0.5 McFarland standard inoculum and after overnight incubation, assessed them for growth (not susceptible) or no growth (susceptible) at a final concentration of 6/6/4 μg/mL ATM-CZA. During the first phase, the precision and accuracy of the BDE were analyzed by testing 61 isolates at all sites. This testing yielded 98.3% precision between sites, with 98.3% categorical agreement and 1.8% major errors (ME). During the second phase, at each site, we evaluated unique, clinical isolates of metallo-β-lactamase (MBL)-producing ( = 75), carbapenem-resistant Pseudomonas aeruginosa ( = 25), Stenotrophomonas maltophilia ( = 46), and sp. ( = 1). This testing resulted in 97.9% categorical agreement, with 2.4% ME. Different results were observed for different disk and CA-MHB manufacturers, requiring a supplemental ATM-CZA-not-susceptible quality control organism to ensure the accuracy of results. The BDE is a precise and effective methodology for determining susceptibility to the combination ATM-CZA.
Topics: Humans; Aztreonam; Anti-Bacterial Agents; Microbial Sensitivity Tests; Ceftazidime; Drug Combinations; Gram-Negative Bacteria; Pseudomonas aeruginosa; beta-Lactamases
PubMed: 37070979
DOI: 10.1128/jcm.01647-22 -
The Journal of Antimicrobial... Dec 2023Antimicrobial resistance in Pseudomonas aeruginosa is complex and multifaceted. While the novel β-lactamase inhibitors (BLIs) avibactam, relebactam and vaborbactam...
BACKGROUND
Antimicrobial resistance in Pseudomonas aeruginosa is complex and multifaceted. While the novel β-lactamase inhibitors (BLIs) avibactam, relebactam and vaborbactam inhibit serine-based β-lactamases, the comparative potency of the novel β-lactam (BL)/BLI combinations against serine carbapenemase-producing P. aeruginosa is unknown.
OBJECTIVES
To compare the in vitro activity of ceftazidime/avibactam, ceftazidime, imipenem/relebactam, imipenem, meropenem/vaborbactam and meropenem against serine β-lactamase-producing P. aeruginosa.
METHODS
Carbapenem-resistant P. aeruginosa were collated through the Enhancing Rational Antimicrobials against Carbapenem-resistant P. aeruginosa (ERACE-PA) Global Surveillance. Isolates positive for serine-based carbapenemases were assessed. MICs were determined by broth microdilution to each novel BL/BLI and BL alone.
RESULTS
GES was the most common carbapenemase identified (n = 59) followed by KPC (n = 8). Ceftazidime/avibactam had MIC50/MIC90 values of 4/8 mg/L and 91% of isolates were susceptible. Conversely, ceftazidime alone was active against only 3% of isolates. The MIC50/MIC90 of imipenem/relebactam were 16/>16 mg/L and 13% of all isolates were defined as susceptible. Of the KPC-producing isolates, 38% were susceptible to imipenem/relebactam, compared with 0% to imipenem. The meropenem/vaborbactam MIC50/MIC90 were >16/>16 mg/L, and 6% of isolates were susceptible, which was similar to meropenem alone (MIC50/90, >8/>8 mg/L; 3% susceptible) suggesting the addition of vaborbactam cannot overcome co-expressed, non-enzymatic resistance mechanisms.
CONCLUSIONS
Among the novel BL/BLIs, ceftazidime/avibactam displayed better in vitro activity and thus is a rational treatment option for serine carbapenemase-harbouring P. aeruginosa. While imipenem/relebactam displayed some activity, particularly against isolates with blaKPC, meropenem/vaborbactam exhibited poor activity, with MICs similar to meropenem alone.
Topics: Meropenem; Ceftazidime; Carbapenems; beta-Lactamase Inhibitors; Pseudomonas aeruginosa; Lactams; Azabicyclo Compounds; Anti-Bacterial Agents; beta-Lactamases; Imipenem; Drug Combinations; Microbial Sensitivity Tests
PubMed: 37840005
DOI: 10.1093/jac/dkad225 -
Antimicrobial Agents and Chemotherapy Nov 2023β-Lactam antibiotics are among the most frequently prescribed therapeutic agents. A common mechanism of resistance toward β-lactam antibiotics is the production of...
β-Lactam antibiotics are among the most frequently prescribed therapeutic agents. A common mechanism of resistance toward β-lactam antibiotics is the production of β-lactamases. These enzymes are capable of hydrolyzing the β-lactam bond, rendering the drug inactive. Among the four described classes, the metallo- β-lactamases (MBLs, class B) employ one or two zinc ions in the active site for catalysis. One of the three most clinically relevant MBLs is New Delhi Metallo- β-Lactamase (NDM-1). The current study sought to investigate the protein evolution of NDM-1 β-lactamase using error-prone polymerase chain reaction. Evaluation revealed that variants were not found to confer higher levels of resistance toward meropenem based on amino acid substitutions. Thus, we postulate that increases in transcription or changes in zinc transport may be clinically more relevant to meropenem resistance than amino acid substitutions.
Topics: Meropenem; beta-Lactamases; beta-Lactams; Zinc; Catalytic Domain; Anti-Bacterial Agents; beta-Lactamase Inhibitors
PubMed: 37874296
DOI: 10.1128/aac.00714-23 -
Microbiology Spectrum Jun 2023Cefiderocol and aztreonam-avibactam (ATM-AVI) both had activity against carbapenem-resistant Gram-negative bacilli, including those that produce metallo-β-lactamases...
Cefiderocol and aztreonam-avibactam (ATM-AVI) both had activity against carbapenem-resistant Gram-negative bacilli, including those that produce metallo-β-lactamases (MBLs). We compared the activities and inoculum effects of these antibiotics against carbapenemase-producing (CPE), especially MBL-producing isolates. The MICs of cefiderocol and ATM-AVI were determined using broth microdilution method for a 2016 to 2021 collection of isolates which produced MBL, KPC, or OXA-48-like carbapenemases. MICs with high bacteria inoculum were also evaluated for susceptible isolates. A total of 195 CPE were tested, including 143 MBL- (74 NDM, 42 IMP, and 27 VIM), 38 KPC-, and 14 OXA-48-like-producing isolates. The susceptible rates of MBL-, KPC-, and OXA-48-like producers to cefiderocol were 86.0%, 92.1%, and 92.9%, respectively, and that to ATM-AVI were 95.8%, 100%, and 100%, respectively. NDM producers displayed lower susceptibility and higher MICs/MICs of cefiderocol (78.4%, 2/16 mg/L) than IMP (92.9%, 0.375/4 mg/L) and VIM (96.3%, 1/4 mg/L) producers. NDM- and VIM-producing Escherichia coli showed lower susceptibility to ATM-AVI (77.3% and 75.0%, respectively) compared to MBL-CPE of other species (100% susceptible). Inoculum effects for cefiderocol and ATM-AVI were observed among 95.9% and 95.2% of susceptible CPE, respectively. A switch from susceptible to resistant category was observed in 83.6% (143/171) of isolates for cefiderocol and 94.7% (179/189) for ATM-AVI. Our results revealed that NDM-producing had lower susceptibility to cefiderocol and ATM-AVI. Prominent inoculum effects on both antibiotics were observed for CPE, which suggested a risk of microbiological failure when they were used for CPE infections with high bacteria burden. The prevalence of infections caused by carbapenem-resistant is increasing worldwide. Currently, therapeutic options for metallo-β-lactamase (MBL)-producing remain limited. We demonstrated that clinical metallo-β-lactamase (MBL)-producing isolates were highly susceptible to cefiderocol (86.0%) and aztreonam-avibactam (ATM-AVI) (95.8%). However, inoculum effects on cefiderocol and ATM-AVI were observed for over 90% of susceptible carbapenemase-producing (CPE) isolates. Our findings highlight a potential risk of microbiological failure when using monotherapy with cefiderocol or ATM-AVI to treat severe CPE infection.
Topics: Humans; Aztreonam; Enterobacteriaceae; Anti-Bacterial Agents; beta-Lactamases; Enterobacteriaceae Infections; Carbapenem-Resistant Enterobacteriaceae; Escherichia coli; Microbial Sensitivity Tests; Cefiderocol
PubMed: 37154758
DOI: 10.1128/spectrum.00569-23 -
Cells Jun 2023β-lactamase enzymes have generated significant interest due to their ability to confer resistance to the most commonly used family of antibiotics in human medicine.... (Review)
Review
β-lactamase enzymes have generated significant interest due to their ability to confer resistance to the most commonly used family of antibiotics in human medicine. Among these enzymes, the class B β-lactamases are members of a superfamily of metallo-β-lactamase (MβL) fold proteins which are characterised by conserved motifs (i.e., HxHxDH) and are not only limited to bacteria. Indeed, as the result of several barriers, including low sequence similarity, default protein annotation, or untested enzymatic activity, MβL fold proteins have long been unexplored in other organisms. However, thanks to search approaches which are more sensitive compared to classical Blast analysis, such as the use of common ancestors to identify distant homologous sequences, we are now able to highlight their presence in different organisms including Bacteria, Archaea, Nanoarchaeota, Asgard, Humans, Giant viruses, and Candidate Phyla Radiation (CPR). These MβL fold proteins are multifunctional enzymes with diverse enzymatic or non-enzymatic activities of which, at least thirteen activities have been reported such as β-lactamase, ribonuclease, nuclease, glyoxalase, lactonase, phytase, ascorbic acid degradation, anti-cancer drug degradation, or membrane transport. In this review, we (i) discuss the existence of MβL fold enzymes in the different domains of life, (ii) present more suitable approaches to better investigating their homologous sequences in unsuspected sources, and (iii) report described MβL fold enzymes with demonstrated enzymatic or non-enzymatic activities.
Topics: Humans; beta-Lactamases; Bacteria; Anti-Bacterial Agents
PubMed: 37443786
DOI: 10.3390/cells12131752 -
Journal of Microbiology, Immunology,... Feb 2024Carbapenem-resistant Klebsiella pneumoniae (CRKP) is capable of causing serious community and hospital-acquired infections. However, currently, the identification of...
BACKGROUND/PURPOSE
Carbapenem-resistant Klebsiella pneumoniae (CRKP) is capable of causing serious community and hospital-acquired infections. However, currently, the identification of CRKP is complex and inefficient. Hence, this study aimed to develop methods for the early and effective identification of CRKP to allow reasonable antimicrobial therapy in a timely manner.
METHODS
K. pneumoniae (KP)-, K. pneumoniae carbapenemase (KPC)- and New Delhi metallo-β-lactamase (NDM)- specific CRISPR RNAs (crRNAs), polymerase chain reaction (PCR) primers and recombinase-aided amplification (RAA) primers were designed and screened in conserved sequence regions. We established fluorescence and lateral flow strip assays based on CRISPR/Cas13a combined with PCR and RAA, respectively, to assist in the detection of CRKP. Sixty-one clinical strains (including 51 CRKP strains and 10 carbapenem-sensitive strains) were collected for clinical validation.
RESULTS
Using the PCR-CRISPR assay, the limit of detection (LOD) for KP and the blaKPC and blaNDM genes reached 1 copy/μL with the fluorescence signal readout. Using the RAA-CRISPR assay, the LOD could reach 10 copies/μL with both the fluorescence signal readout and the lateral flow strip readout. Additionally, the positivity rates of CRKP-positive samples detected by the PCR/RAA-CRISPR fluorescence and RAA-CRISPR lateral flow strip methods was 92.16% (47/51). The sensitivity and specificity reached 100% for KP and blaKPC and blaNDM gene detection. For detection in a simulated environmental sample, 1 CFU/cm KP could be detected.
CONCLUSION
We established PCR/RAA-CRISPR assays for the detection of blaKPC and blaNDM carbapenemase genes, as well as KP, to facilitate the detection of CRKP.
Topics: Humans; Anti-Bacterial Agents; Klebsiella pneumoniae; CRISPR-Cas Systems; Microbial Sensitivity Tests; beta-Lactamases; Carbapenems; Carbapenem-Resistant Enterobacteriaceae; Klebsiella Infections
PubMed: 37963801
DOI: 10.1016/j.jmii.2023.10.010 -
Ugeskrift For Laeger Jun 2023This is a case report of a Ukrainian war-injured patient who was colonised/infected with nine different carbapenemase-producing organisms (CPO). The patient was...
This is a case report of a Ukrainian war-injured patient who was colonised/infected with nine different carbapenemase-producing organisms (CPO). The patient was initially treated in Ukraine. After two months he was admitted to a Danish hospital where he underwent extensive surgery and received broad-spectrum antibiotics. In screening and clinical samples, nine different CPO were cultured which in combination were untreatable with antibiotics. To our knowledge, this is the first patient in Denmark with such a high number of different CPO. This may be a sign that we are entering a postantibiotic era.
Topics: Male; Humans; Bacterial Proteins; beta-Lactamases; Anti-Bacterial Agents
PubMed: 37325986
DOI: No ID Found -
Emerging Microbes & Infections Dec 2023Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) bacteremia can have poor clinical outcomes. Thus, determining the predictors of mortality from... (Meta-Analysis)
Meta-Analysis Review
Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) bacteremia can have poor clinical outcomes. Thus, determining the predictors of mortality from ESBL-PE bacteremia is very important. The present systematic review and meta-analysis aimed to evaluate studies to determine predictors associated with ESBL-PE bacteremia mortality. We searched PubMed and Cochrane Library databases for all relevant publications from January 2000 to August 2022. The outcome measure was mortality rate. In this systematic review of 22 observational studies, 4607 patients with ESBL-PE bacteremia were evaluated, of whom 976 (21.2%) died. The meta-analysis showed that prior antimicrobial therapy (RR, 2.89; 95% CI, 1.22-6.85), neutropenia (RR, 5.58; 95% CI, 2.03-15.35), nosocomial infection (RR, 2.46; 95% CI, 1.22-4.95), rapidly fatal underlying disease (RR, 4.21; 95% CI, 2.19-8.08), respiratory tract infection (RR, 2.12; 95% CI, 1.33-3.36), Pitt bacteremia score (PBS) (per1) (RR, 1.35; 95% CI, 1.18-1.53), PBS ≥ 4 (RR, 4.02; 95% CI, 2.77-5.85), severe sepsis (RR, 11.74; 95% CI, 4.68-29.43), and severe sepsis or septic shock (RR, 4.19; 95% CI, 2.83-6.18) were found to be mortality predictors. Moreover, urinary tract infection (RR, 0.15; 95% CI, 0.04-0.57) and appropriate empirical therapy (RR, 0.39; 95% CI, 0.18-0.82) were found to be a protective factor against mortality. Patients with ESBL-PE bacteremia who have the aforementioned require prudent management for improved outcomes. This research will lead to better management and improvement of clinical outcomes of patients with bacteremia caused by ESBL-PE.
Topics: Humans; Enterobacteriaceae Infections; Enterobacteriaceae; Bacteremia; Sepsis; beta-Lactamases; Anti-Bacterial Agents; Retrospective Studies; Treatment Outcome
PubMed: 37219067
DOI: 10.1080/22221751.2023.2217951 -
Frontiers in Cellular and Infection... 2023Antibiotic resistance has become a serious threat to global public health and economic development. Rapid and accurate identification of a patient status for...
Antibiotic resistance has become a serious threat to global public health and economic development. Rapid and accurate identification of a patient status for antimicrobial resistance (AMR) are urgently needed in clinical diagnosis. Here we describe the development of an assay method for activity fingerprinting of AMR β-lactamases using panels of 7 β-lactam antibiotics in 35 min. New Deli Metallo β-lactamase-1 (NDM-1) and penicillinase were demonstrated as two different classes of β-lactamases. The panel consisted of three classes of antibiotics, including: penicillins (penicillin G, piperacillin), cephalosporins (cefepime, ceftriaxone, cefazolin) and carbapenems (meropenem and imipenem). The assay employed a scheme combines the catalytic reaction of AMR β-lactamases on antibiotic substrates with a flow-injected thermometric biosensor that allows the direct detection of the heat generated from the enzymatic catalysis, and eliminates the need for custom substrates and multiple detection schemes. In order to differentiate classes of β-lactamases, characterization of the enzyme activity under different catalytic condition, such as, buffer composition, ion strength and pH were investigated. This assay could provide a tool for fast diagnosis of patient AMR status which makes possible for the future accurate treatment with selected antibiotics.
Topics: Humans; beta-Lactamases; Anti-Bacterial Agents; Carbapenems; Cefazolin; Cefepime
PubMed: 37743856
DOI: 10.3389/fcimb.2023.1222156 -
European Journal of Clinical... Mar 2024The occurrence of metallo-beta-lactamase-producing Pseudomonas aeruginosa (MBL-PA) isolates is increasing globally, including in Switzerland. The aim of this study was...
OBJECTIVES
The occurrence of metallo-beta-lactamase-producing Pseudomonas aeruginosa (MBL-PA) isolates is increasing globally, including in Switzerland. The aim of this study was to characterise, phenotypically and genotypically, the MBL-PA isolates submitted to the Swiss National Reference Center for Emerging Antibiotic Resistance (NARA) reference laboratory over a 12-month period from July 2022 to July 2023.
METHODS
Thirty-nine non-duplicate MBL-PA Isolates were submitted to NARA over the study period from across Switzerland. Susceptibility was determined by broth microdilution according to EUCAST methodology. Whole-genome sequencing was performed on 34 isolates. Sequence types (STs) and resistance genes were ascertained using the Centre for Genomic Epidemiology platform. MBL genes, bla, bla, and bla, were cloned into vector pUCP24 and transformed into P. aeruginosa PA14.
RESULTS
The most prevalent MBL types identified in this study were VIM (21/39; 53.8%) followed by NDM (11/39; 28.2%), IMP (6/39; 15.4%), and a single isolate produced both VIM and NDM enzymes. WGS identified 13 different STs types among the 39 isolates. They all exhibited resistance to cephalosporins, carbapenems, and the beta-lactam-beta-lactamase inhibitor combinations, ceftolozane-tazobactam, ceftazidime-avibactam, imipenem-relebactam, and meropenem-vaborbactam, and 8 isolates were cefiderocol (FDC) resistant. Recombinant P. aeruginosa strains producing bla, bla, and bla exhibited FDC MICs of 16, 8, and 1 mg/L, respectively.
CONCLUSIONS
This study showed that the MBL-PA in Switzerland could be attributed to the wide dissemination of high-risk clones that accounted for most isolates in this study. Although FDC resistance was only found in 8 isolates, MBL carriage was shown to be a major contributor to this phenotype.
Topics: Humans; Pseudomonas aeruginosa; Switzerland; beta-Lactamases; Anti-Bacterial Agents; Carbapenems; Microbial Sensitivity Tests; Pseudomonas Infections
PubMed: 38233610
DOI: 10.1007/s10096-024-04752-8