avibactam and Klebsiella-Infections

Carbapenemase-producing Enterobacterales represent a major cause of difficult-to-treat infections world-wide. Novel β-lactam/β-lactamase inhibitor combinations, including ceftazidime/avibactam (CZA), meropenem/vaborbactam (MVB), and imipenem/relebactam (IMR), represented a break-through in the treatment of some carbapenemase-producing Enterobacterales infections. However, acquired resistance to these agents has been reported in Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales. Herein, we reported an outbreak caused by CZA-resistant, KPC-producing Klebsiella pneumoniae (KPC-Kp), which was also variably resistant to carbapenem-based β-lactam/β-lactamase inhibitor combinations.. Bacterial isolates were subjected to antimicrobial susceptibility testing, whole-genome sequencing, determination of bla. Overall, 15 KPC-Kp, nine CZA-resistant (CZA. In this multi-clonal outbreak of KPC-Kp, the overproduction of KPC-3 was the leading mechanism of cross-resistance to CZA and MVB, whereas resistance to IMR appeared less affected. The emergence and dissemination of similar resistance mechanisms may have relevant clinical and diagnostic implications, and their surveillance is warranted.

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamase Inhibitors; beta-Lactamases; Carbapenems; Ceftazidime; Disease Outbreaks; Drug Combinations; Humans; Klebsiella; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

Ceftazidime-avibactam (CAZ-AVI)-based treatments have been associated with the emergence of resistance in KPC-producing Klebsiella pneumoniae (KPC-Kp) isolates after antimicrobial exposure. Here, we evaluated the CAZ-AVI resistance development in KPC-Kp isolated from patients treated with CAZ-AVI-based therapy.. We enrolled adult patients treated with CAZ-AVI-based regimens between January 2020 and January 2021. Carbapenemase-producing isolates collected from clinical samples and rectal swabs were evaluated for CAZ-AVI resistance development after antimicrobial exposure. KPC-Kp developing CAZ-AVI resistance and parental susceptible strains were genomically characterized. Whole genome sequencing was performed by using the Illumina iSeq100 platform and genomes were analyzed for antimicrobial-resistance genes, plasmid and porins sequences.. We enrolled 90 patients treated with CAZ-AVI-based therapy and 62.2% (56/90) of them were colonized by KPC-producers before CAZ-AVI-based treatment and 6.6% acquired colonization during therapy. Six (6.6%) patients developed infections because of resistant KPC-Kp after CAZ-AVI exposure and 3 (3.3%) of them developed CAZ-AVI resistance in the rectum. Development of resistance among KPC in the rectum occurred after 32 (IQR, 9-35) days of therapy and after 30 (IQR, 22-40) days in clinical specimens. Genetic analysis demonstrated that the development of CAZ-AVI resistance was associated with mutated bla. Antimicrobial exposure induce a higher incidence of CAZ-AVI resistance development in the blood and respiratory tract than in the rectum (6.7% vs. 3.3%) of CAZ-AVI-treated patients and genome analysis showed that resistance was associated with mutated bla

Topics: Adult; Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Ceftazidime; Critical Illness; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Phylogeny

In this study, we aimed to clarify the evolutionary trajectory of a Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) population during β-lactam antibiotic therapy. Five KPC-Kp isolates were collected from a single patient. Whole-genome sequencing and a comparative genomics analysis were performed on the isolates and all

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Cefiderocol; Ceftazidime; Drug Combinations; Humans; Klebsiella; Klebsiella Infections; Klebsiella pneumoniae; Meropenem; Microbial Sensitivity Tests; Moxalactam

This study was aimed at investigating risk factors for mortality in patients suffering from KPC-producing Klebsiella pneumoniae (KPC-Kp) bloodstream infections (BSIs), evaluating the impact of rapid diagnostics and ceftazidime/avibactam use. This observational retrospective study (January 2017-May 2021) included all patients with a KPC-Kp BSI. Uni-multivariable analyses were carried out to evaluate the effect of clinical variables on both in-hospital death (IHD) and 30-day all-cause mortality, and the role of the combination of ceftazidime/avibactam plus polymyxin. One hundred and ninety-six patients met the study's inclusion criteria. Older age, having undergone renal replacement therapy during the 30 days preceding the KPC-Kp BSI onset, having an INCREMENT-CPE score ≥ 8, and having suffered from a superimposed and/or following KPC-Kp BSI treatment candidemia were found to be the main factors associated with both mortality rates. Among protective factors, the centrality of ceftazidime/avibactam in monotherapy (IHD: OR: 0.34; CI 95%: 0.11-1.00-30-day all-cause mortality: OR: 0.18; CI 95%: 0.04-0.77) or combination (IHD: OR: 0.51; CI 95%: 0.22-1.19-30-day all-cause mortality: OR: 0.62; CI 95%: 0.21-1.84) emerged and became even more evident once the effect of ceftazidime/avibactam plus polymyxin was removed. Rapid diagnostics may be useful to adopt more effective strategies for the treatment of KPC-Kp BSI patients and implement infection control measures, even if not associated with higher patient survival. Ceftazidime/avibactam, even when used alone, represents an important option against KPC-Kp, while combined use with polymyxin might not have altered its efficacy. Patient comorbidities, severity of BSI, and complications such as candidemia were confirmed to have a significant burden on survival.

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Candidemia; Ceftazidime; Drug Combinations; Hospital Mortality; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Polymyxins; Rapid Diagnostic Tests; Retrospective Studies

Ceftazidime/avibactam and cefiderocol are two of the latest antibiotics with activity against a wide variety of Gram-negatives, including carbapenem-resistant Enterobacterales. We sought to describe the phenotypic and genotypic characteristics of ceftazidime/avibactam- and cefiderocol-resistant KPC-Klebsiella pneumoniae (KPC-Kp) detected during an outbreak in 2020 in the medical ICU of our hospital.. We collected 11 KPC-Kp isolates (6 clinical; 5 surveillance samples) resistant to ceftazidime/avibactam and cefiderocol from four ICU patients (November 2020 to January 2021), without prior exposure to these agents. All patients had a decontamination regimen as part of the standard ICU infection prevention protocol. Additionally, one ceftazidime/avibactam- and cefiderocol-resistant KPC-Kp (June 2019) was retrospectively recovered. Antibiotic susceptibility was determined by broth microdilution. β-Lactamases were characterized and confirmed. WGS was also performed.. All KPC-Kp isolates (ceftazidime/avibactam MIC  ≥16/4 mg/L; cefiderocol MIC ≥4 mg/L) were KPC + CTX-M-15 producers and belonged to the ST307 high-risk-clone (ST307-HRC). KPC-62 (L168Q) was detected in all isolates involved in the 2020 outbreak, contained in January 2021. KPC-31 (D179Y) was identified in the KPC-Kp from 2019. Cloning experiments demonstrated that both blaKPC-62 and blaKPC-31 were responsible for ceftazidime/avibactam resistance (MIC >16 mg/L) and an increased cefiderocol MIC. Additionally, mutations in OmpA and EnvZ/OmpR porin proteins (in KPC-62-Kp) and in PBP2 (in KPC-31-Kp) were found and may be involved in cefiderocol resistance.. The emergence of resistance to both ceftazidime/avibactam and cefiderocol in KPC-Kp-HRCs, together with the diversification of novel KPC enzymes displaying different antibiotic resistance phenotypes, is an epidemiological and clinical risk.

Topics: Bacterial Proteins; Cefiderocol; Ceftazidime; Hospitals, University; Humans; Klebsiella Infections; Klebsiella pneumoniae; Retrospective Studies; Spain

Little is known regarding outcomes and optimal therapeutic regimens of infections caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) resistant to ceftazidime/avibactam (CZA) and susceptible to meropenem (MEM). Although susceptible to MEM in vitro, the possibility of developing MEM resistance overtime is a concern. We describe the clinical characteristics of patients with colonization/infection due to KPC variants with a focus on the in vitro activity of fosfomycin (FOS)-containing combinations.. Patients with colonization/infection due to a KPC variant were included. Fosfomycin susceptibility was performed by agar dilution method. Synergistic activity of FOS-based combinations was evaluated by gradient strip-agar diffusion method. The emergence of in vitro MEM resistance was also tested.. Eleven patients were included: eight with infection [four with ventilator-associated pneumonia and four with bloodstream infections] and three with colonization. Previous therapy with CZA was administered to all patients (with a mean cumulative duration of 23 days). All subjects with infection received meropenem, in monotherapy (n = 4) or with amikacin (n = 2) or fosfomycin (n = 2), and achieved clinical cure. A new CZA-susceptible and MEM-resistant KPC-Kp strain was subsequently isolated in three patients (27.3%). Meropenem/vaborbactam (MVB) showed high in vitro activity, while FOS+MEM combination was synergistic in 40% of cases. In vitro resistance to MEM was observed with maintenance of CZA resistance.. Detection of KPC variants may occur within the same patient, especially if CZA has been previously administered. Although clinical success has been obtained with carbapenems, the emergence of MEM resistance is a concern. Fosfomycin plus meropenem is synergistic and may be a valuable combination option for KPC variants, while MVB may be considered in monotherapy. The detection of KPC variants in an endemic setting for KPC-Kp represents a worryingly emerging condition. The optimal therapeutic approach is still unknown and the development of meropenem resistance is of concern, which may lead to therapeutic failure in clinical practice. In these cases, the addition of fosfomycin to meropenem, or a more potent antibiotic, such as meropenem/vaborbactam, may be valuable therapeutic options.

Topics: Agar; Ceftazidime; Fosfomycin; Humans; Klebsiella Infections; Klebsiella pneumoniae; Meropenem

Klebsiella pneumoniae AR 0047 from the CDC and FDA Antibiotic Resistance Isolate Bank is resistant to cefiderocol, a siderophore-conjugated cephalosporin. Genomics analysis and genetic complementation revealed that a frameshift mutation in

Topics: Anti-Bacterial Agents; beta-Lactamases; Cefiderocol; Cephalosporins; Escherichia coli; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Porins

Today, Klebsiella pneumoniae strains are sophisticatedly associated with the transmission of KPC, and ST11 clones carrying KPC-2 are an important target for anti-infective clinical therapy, posing a very high threat to patients. To present the detailed genetic features of two KPC-2 core structures of F94_plasmid pA, the whole genome of K. pneumoniae strain F94 was sequenced by nanopore and illumina platform, and mobile genetic elements associated with antibiotic-resistance genes were analyzed with a series of bioinformatics methods. K. pneumoniae strain F94, identified as a class A carbapenemase-resistant Enterobacteriaceae, was resistant to most tested antibiotics, especially to low-levels of ceftazidime/avibactam (avibactam ≤ 4 mg/L), owing to overexpression of the two KPC-2 in F94_plasmid pA. However, strain F94 was sensitive to high-levels of ceftazidime/avibactam (avibactam ≥ 8 mg/L), which correlated with further inhibition of ceftazidime hydrolysis by the KPC-2 enzyme due to the multiplication of avibactam. Collinearity analysis indicated that multi-drug resistance (MDR) regions of plasmids with the tandam repeats of two or more KPC-2 core structures share highly similar structures. This study characterized the MDR region of the F94_ plasmid pA as homologous to plasmids pKPC2_090050, pKPC2_090374, plasmid unnamed 2, pC2414-2-KPC, pKPC2-020037, pBS1014-KPC2, pKPC-J5501, and pKPC2-020002, which contained the tandem repeats of one, two, or more KPC-2 core structures, providing insight into the evolution of multidrug resistance in K. pneumoniae. An alternative theoretical basis for exploring the tandem repeats of two or more KPC-2 core structures was developed by analyzing and constructing the homologous sequence of F94_ plasmid pA.

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Ceftazidime; Drug Combinations; Hospitals; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Plasmids

The study aimed to investigate prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) blood culture isolates and their susceptibility to two new antibiotics, imipenem/relebactam and ceftazidime/avibactam. Out of 765 isolates recovered from blood cultures in a tertiary care hospital in Serbia between 2020 and 2023, 143 non-repetitive K. pneumoniae strains were included in this study. Minimum inhibitory concentration (MIC) values of the examined antimicrobial drugs was determined by VITEK 2 system, MIC test strip (imipenem/relebactam and ceftazidime/avibactam), and broth microdilution method (tigecycline and colistin). Carbapenemase-encoding genes (blaKPC, blaOXA-48-like, blaNDM, blaVIM, blaIMP) were detected using a multiplex-PCR assay, the BioFire-Blood Culture Identification 2-panel. This closed molecular assay is designed for the BioFire® FilmArray® system, enabling automated sample preparation, amplification, detection, and analysis (bioMérieux, France). Results revealed that K. pneumoniae was the most common isolate from blood cultures in 2022. The prevalence of K. pneumoniae was about 11.6% in 2020 and 2021, while in 2022 it raised to over 30%. Also, the frequency of CRKP increased from 11.76% in 2020, through 15.29% in 2021 to 72.94% in 2022. The majority of CRKP carried blaOXA-48-like (60.0%), followed by blaKPC (16.47%), and blaNDM (8.24%) genes, while 14.12% harboured both blaOXA-48-like and blaNDM genes. Only 25.88% of CRKP isolates were resistant to ceftazidime/avibactam, while 51.76% were resistant to imipenem/relebactam and colistin. The rapid spread of CRKP is particularly concerning because therapeutic options are limited to a few antibiotics. While imipenem/relebactam and colistin showed similar antimicrobial activity against CRKP clinical isolates, ceftazidime/avibactam proved to be the most effective antibiotic.

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Blood Culture; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Ceftazidime; Colistin; Drug Combinations; Hospitals, University; Humans; Imipenem; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Serbia

To assess the impact of carbapenem resistance on mortality in Klebsiella pneumoniae bloodstream infection (BSI) in the era of novel β-lactam/β-lactamase inhibitor combinations.. Retrospective study of patients with K. pneumoniae BSI between January and August 2020 in 16 centres (CARBANEW study within the MULTI-SITA project).. Overall, 426 patients were included: 107/426 (25%) had carbapenem-resistant K. pneumoniae (CR-Kp) BSI and 319/426 (75%) had carbapenem-susceptible K. pneumoniae (CS-Kp) BSI. Crude cumulative 30 day mortality was 33.8% and 20.7% in patients with, respectively, CR-Kp BSI and CS-Kp BSI (P = 0.027). Carbapenemase production or carbapenemase-encoding genes were detected in 84/98 tested CR-Kp isolates (85.7%), mainly KPC (78/84; 92.9%). Ceftazidime/avibactam was the most frequently used appropriate therapy for CR-Kp BSI (80/107; 74.7%). In multivariable analyses, variables showing an unfavourable association with mortality after correction for multiple testing were age-adjusted Charlson comorbidity index (HR 1.20; 95% CI 1.10-1.31, P < 0.001) and Pitt score (HR 1.33; 95% CI 1.15-1.55, P < 0.001), but not carbapenem resistance (HR 1.28, 95% CI 0.74-2.22, P = 0.410). In a propensity score-matched analysis, there was no difference in mortality between patients appropriately treated with ceftazidime/avibactam for CR-Kp BSI and patients appropriately treated with other agents (mainly meropenem monotherapy or piperacillin/tazobactam monotherapy) for CS-Kp BSI (HR 1.07; 95% CI 0.50-2.29, P = 0.866).. Our results suggest that the increased mortality in CR-Kp BSI compared with CS-Kp BSI is not (or no longer) dependent on the type of therapy in areas where ceftazidime/avibactam-susceptible KPC-producing isolates are the most prevalent type of CR-Kp.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacteremia; Bacterial Proteins; beta-Lactamase Inhibitors; beta-Lactamases; Carbapenems; Ceftazidime; Disease Susceptibility; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Retrospective Studies; Sepsis

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Ceftazidime; Drug Combinations; Humans; Klebsiella; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Ceftazidime; Drug Combinations; Genomics; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

In February 2022, a critically ill patient colonized with a carbapenem-resistant K. pneumoniae producing KPC-3 and VIM-1 carbapenemases was hospitalized for SARS-CoV-2 in the intensive care unit of Policlinico Umberto I hospital in Rome, Italy. During 95 days of hospitalization, ceftazidime/avibactam, meropenem/vaborbactam, and cefiderocol were administered consecutively to treat 3 respiratory tract infections sustained by different bacterial agents. Those therapies altered the resistome of K. pneumoniae sequence type 512 colonizing or infecting the patient during the hospitalization period. In vivo evolution of the K. pneumoniae sequence type 512 resistome occurred through plasmid loss, outer membrane porin alteration, and a nonsense mutation in the cirA siderophore gene, resulting in high levels of cefiderocol resistance. Cross-selection can occur between K. pneumoniae and treatments prescribed for other infective agents. K. pneumoniae can stably colonize a patient, and antimicrobial-selective pressure can promote progressive K. pneumoniae resistome evolution, indicating a substantial public health threat.

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Cefiderocol; Ceftazidime; Humans; Italy; Klebsiella Infections; Klebsiella pneumoniae; Meropenem; Microbial Sensitivity Tests

Topics: Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Carbapenem-Resistant Enterobacteriaceae; Ceftazidime; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

Ceftazidime/avibactam (CZA) is used to treat infections caused by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp). Resistance to CZA is commonly related to point mutations in the bla

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Ceftazidime; Drug Combinations; Drug Resistance, Bacterial; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

The novel carbapenem/β-lactamase inhibitor combination imipenem/cilastatin/relebactam has been developed for the treatment of infections due to carbapenemase-producing Enterobacteriaceae (CPE). Herein, we describe the in vivo evolution of imipenem/cilastatin/relebactam resistance in longitudinal intra-patient Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) strains isolated from a patient following ceftazidime/avibactam-based treatments.. WGS analysis was performed on KPC-Kp strains isolated at different times and during antimicrobial treatments from the same patient. Genome assemblies were performed using a hybrid approach using Illumina iSeq 100 and Minion Oxford Nanopore platforms. Subpopulation analysis and allele frequency determination was performed by mapping Illumina reads to blaKPC.. During antimicrobial treatment, resistance to ceftazidime/avibactam was observed following 16 days of antimicrobial therapy. WGS results showed that all KPC-Kp exhibited a low SNP rate of divergence, belonged to ST512 and shared similar antimicrobial resistance and porin gene patterns. Genetic analysis demonstrated that the first ceftazidime/avibactam-resistant KPC-Kp strain harboured a blaKPC-53 gene in a Tn4401 transposon moved from IncFII(K) to a 43 kb IncX3 plasmid, while a imipenem/cilastatin/relebactam-resistant strain exhibited two copies of the Tn4401 transposon in IncFII(K) and IncX3 plasmids, resulting in an increased blaKPC copy number. Of note, frequency analysis demonstrated that imipenem/cilastatin/relebactam-resistant KPC-Kp consisted of mixed subpopulations harbouring blaKPC-40 and blaKPC-53 alleles.. Our results show the in vivo evolution of genetic rearrangement conferring resistance to imipenem/relebactam in a patient with KPC-Kp infection and treated with different ceftazidime/avibactam-based treatments. The rapid development of mutations and the high adaptability of its genome highlight the potential threat of KPC-Kp.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Ceftazidime; Cilastatin; Drug Combinations; Humans; Imipenem; Klebsiella; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

To describe the clinical and microbiological features of a case of community-acquired infection by KPC-producing K. pneumoniae (KPCKP) resistant to ceftazidime/avibactam (CAZ-AVI).. Identification of microorganisms was performed with MALDI Biotyper CA System (BrukerDaltonics, Madrid, Spain). Antimicrobial susceptibility testing was performed using Sensitre EURGNCOL panels (Thermo Fisher Scientific, Madrid, Spain) and gradient strips (Etest, bioMérieux, Madrid, Spain) in the case of CAZ-AVI, using EUCAST breakpoints for interpretation. Whole genome sequencing of blood culture and rectal swab isolates was performed using the Illumina NovaSeq 6000 sequencing system, with 2 × 150-bp paired-end reads (Illumina, Inc.).. Blood culture and rectal swab KPCKP isolates were resistant to carbapenems and to CAZ-AVI. The blood culture isolate showed susceptibility to trimethoprim-sulfamethoxazole (TMP-SMX), but the rectal swab culture isolate was resistant to this antibiotic. Both isolates belonged to clonal lineage ST512, harboured a single copy of bla. Resistance to ceftazidime-avibactam is an emerging nosocomial problem. This case shows that CAZ-AVI-resistant KPCKP strains may disseminate into the community and cause serious infections.

Topics: Azabicyclo Compounds; Bacteremia; Ceftazidime; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Trimethoprim, Sulfamethoxazole Drug Combination

Topics: Animals; Anti-Bacterial Agents; Azabicyclo Compounds; Aztreonam; beta-Lactamase Inhibitors; beta-Lactamases; Carbapenems; Drug Collateral Sensitivity; Klebsiella Infections; Klebsiella pneumoniae; Mice; Microbial Sensitivity Tests; Porins; Protease La; Proteomics; Tetracyclines

Infections due to carbapenem-resistant Enterobacterales are considered urgent public health threats and often treated with a β-lactam/β-lactamase inhibitor combination. However, clinical treatment failure and resistance emergence have been attributed to inadequate dosing. We used a novel framework to provide insights of optimal dosing exposure of ceftazidime/avibactam.. Seven clinical isolates of Klebsiella pneumoniae producing different KPC variants were examined. Ceftazidime susceptibility (MIC) was determined by broth dilution using escalating concentrations of avibactam. The observed MICs were characterized as response to avibactam concentrations using an inhibitory sigmoid Emax model. Using the best-fit parameter values, %fT>MICi was estimated for various dosing regimens of ceftazidime/avibactam. A hollow-fibre infection model (HFIM) was subsequently used to ascertain the effectiveness of selected regimens over 120 h. The drug exposure threshold associated with bacterial suppression was identified by recursive partitioning.. In all scenarios, ceftazidime MIC reductions were well characterized with increasing avibactam concentrations. In HFIM, bacterial regrowth over time correlated with emergence of resistance. Overall, suppression of bacterial regrowth was associated with %fT>MICi ≥ 76.1% (100% versus 18.2%; P < 0.001). Using our framework, the optimal drug exposure could be achieved with ceftazidime/avibactam 2.5 g every 12 h in 5 out of 7 isolates. Furthermore, ceftazidime/avibactam 2.5 g every 8 h can suppress an isolate deemed resistant based on conventional susceptibility testing method.. An optimal drug exposure to suppress KPC-producing bacteria was identified. The novel framework is informative and may be used to guide optimal dosing of other β-lactam/β-lactamase inhibitor combinations. Further in vivo investigations are warranted.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamase Inhibitors; beta-Lactamases; Ceftazidime; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

Infections caused by KPC-producing Klebsiella pneumoniae (Kp) are associated with high mortality. Therefore, new treatment options are urgently required.. To assess the outcomes and predictors of mortality in patients with KPC- or OXA-48-Kp infections treated with ceftazidime/avibactam with an emphasis on KPC-Kp bloodstream infections (BSIs).. A multicentre prospective observational study was conducted between January 2018 and March 2019. Patients with KPC- or OXA-48-Kp infections treated with ceftazidime/avibactam were included in the analysis. The subgroup of patients with KPC-Kp BSIs treated with ceftazidime/avibactam was matched by propensity score with a cohort of patients whose KPC-Kp BSIs had been treated with agents other than ceftazidime/avibactam with in vitro activity.. One hundred and forty-seven patients were identified; 140 were infected with KPC producers and 7 with OXA-48 producers. For targeted therapy, 68 (46.3%) patients received monotherapy with ceftazidime/avibactam and 79 (53.7%) patients received ceftazidime/avibactam in combination with at least another active agent. The 14 and 28 day mortality rates were 9% and 20%, respectively. The 28 day mortality among the 71 patients with KPC-Kp BSIs treated with ceftazidime/avibactam was significantly lower than that observed in the 71 matched patients, whose KPC-Kp BSIs had been treated with agents other than ceftazidime/avibactam (18.3% versus 40.8%; P = 0.005). In the Cox proportional hazards model, ultimately fatal disease, rapidly fatal disease and Charlson comorbidity index ≥2 were independent predictors of death, whereas treatment with ceftazidime/avibactam-containing regimens was the only independent predictor of survival.. Ceftazidime/avibactam appears to be an effective treatment against serious infections caused by KPC-Kp.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Ceftazidime; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Registries

The present study evaluated the carbapenem resistance mechanisms of Klebsiella pneumoniae strains isolated in two Greek tertiary teaching hospitals and their susceptibility to currently used and novel antimicrobial agents.Forty-seven carbapenem resistant K. pneumoniae strains were collected in G. Papanikolaou and Ippokrateio hospital of Thessaloniki between 2016 and 2018. Strain identification and antimicrobial susceptibility was conducted by Vitek 2 system (Biomérieux France). Susceptibility against new antimicrobial agents was examined by disk diffusion method. Polymerase chain reaction (PCR) was used to detect blaKPC, blaVIM, blaNDM and blaOXA-48 genes.The meropenem-EDTA and meropenem-boronic acid synergy test performed on the 24 K. pneumoniae strains demonstrated that 8 (33.3%) yielded positive for metallo-beta-lactamases (MBL) and 16 (66.6%) for K. pneumonia carbapenemases (KPC) production. Colistin demonstrated the highest in vitro activity (87.7%) among the 47 K. pneumoniae strains followed by gentamicin (76.5%) and tigecycline (51%). Among new antibiotics ceftazidime/avibactam showed the highest sensitivity (76.6%) in all strains followed by eravacycline (66.6%). The blaKPC gene was present in 30 strains (63.8%), the blaNDM in 11 (23.4%) and the blaVIM in 6 (12.8%). The blaOXA-48 gene was not detected.Well established antimicrobial agents such as colistin, gentamicin and tigecycline and novel antibiotics like ceftazidime/avibactam and eravacycline can be reliable options for the treatment of invasive infections caused by carbapenem-resistant K. pneumoniae.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Carbapenems; Ceftazidime; Greece; Hospitals, Teaching; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Tetracyclines

Despite major advances in the β-lactamase inhibitor field, certain enzymes remain refractory to inhibition by agents recently introduced. Most important among these are the class B (metallo) enzyme NDM-1 of Enterobacteriaceae and the class D (OXA) enzymes of

Topics: Animals; Bacteria; beta-Lactamase Inhibitors; Borinic Acids; Boronic Acids; Carboxylic Acids; Drug Discovery; Klebsiella Infections; Mice; Microbial Sensitivity Tests; Structure-Activity Relationship

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Aztreonam; beta-Lactamases; Ceftazidime; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Nebulizers and Vaporizers; Powders; Sepsis

KPC-producing Klebsiella pneumonia (KPC-Kp) represents a major therapeutic challenge in critically ill patients. Ceftazidime-avibactam (CAZ-AVI) is a new effective drug against KPC-Kp but, due to emerging resistant strains during monotherapy, the association with a second antibiotic has been advocated. Therefore, intravenous fosfomycin may be a possible choice for combination therapy. The aim of this study was to evaluate the in vitro susceptibility of CAZ-AVI alone and in combination with fosfomycin and carbapenems against KPC-Kp clinical isolates by E-test method. The combination of CAZ-AVI with carbapenems showed synergistic activity, whereas with fosfomycin showed addictive activity, suggesting that fosfomycin may be a carbapenem-sparing strategy in antimicrobial stewardship programs.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamases; Carbapenems; Ceftazidime; Drug Combinations; Fosfomycin; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacteremia; Bacterial Proteins; beta-Lactamases; Ceftazidime; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Ceftazidime; Clone Cells; Drug Combinations; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests

The aim of this study was to report on in vitro tests of antibacterial activity of ceftazidime/avibactam in combination against planktonic or biofilm KPC carbapenemase-producing Klebsiella pneumoniae (KPC-Kp), the rate of KPC-Kp blood isolates in University of Perugia Hospital over a 5-year period, and their antimicrobial susceptibility patterns.. The antibacterial activity of ceftazidime/avibactam in combination with other antimicrobials was assessed against planktonic and biofilm bacteria by Etest and checkerboard assay. A retrospective review of laboratory data was performed to evaluate the rate of KPC-Kp from blood samples and their antimicrobial susceptibility patterns.. Between 2014 and 2019, 130/4241 (3.1%) KPC-Kp were identified from blood cultures. Their rate increased from 2.3% in 2014-2015 to 4.5% over the last 3 years. Overall, 4.6% (6/130) of KPC-Kp isolates were susceptible to meropenem, 65.4% (85/130) to colistin, 65.1% (84/129) to tigecycline, 34.6% (45/130) to amikacin, 36.2% (42/116) to gentamicin, 40.2% (39/97) to fosfomycin and 91.5% (65/71) to ceftazidime/avibactam. Five of six ceftazidime/avibactam-resistant KPC-Kp were isolated from patients not treated with ceftazidime/avibactam. Synergism was detected both by Etest and checkerboard assay for the combination of ceftazidime/avibactam plus meropenem against planktonic isolates, whilst lower bactericidal activity was observed in biofilm KPC-Kp isolates.. Our in vitro data suggest that the combination of ceftazidime/avibactam plus meropenem has a synergistic antibacterial activity against planktonic bacteria, whilst a lower activity was detected against biofilm, suggesting worse clinical outcomes whenever biofilm infections are present. Further analyses are required to confirm these results before extending them to clinical practice.

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Biofilms; Ceftazidime; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Plankton; Retrospective Studies

Infections caused by New Delhi metallo-β-lactamase (NDM)-producing strains of multidrug-resistant Klebsiella pneumoniae are a global public health threat lacking reliable therapies. NDM is impervious to all existing β-lactamase inhibitor (BLI) drugs, including the non-β-lactam BLI avibactam (AVI). Though lacking direct activity against NDMs, AVI can interact with penicillin-binding protein 2 in a manner that may influence cell wall dynamics. We found that exposure of NDM-1-producing K. pneumoniae to AVI led to striking bactericidal interactions with human cathelicidin antimicrobial peptide LL-37, a frontline component of host innate immunity. Moreover, AVI markedly sensitized NDM-1-producing K. pneumoniae to killing by freshly isolated human neutrophils, platelets, and serum when complement was active. Finally, AVI monotherapy reduced lung counts of NDM-1-producing K. pneumoniae in a murine pulmonary challenge model. AVI sensitizes NDM-1-producing K. pneumoniae to innate immune clearance in ways that are not appreciated by standard antibiotic testing and that merit further study.

Topics: Animals; Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamases; Carbapenem-Resistant Enterobacteriaceae; Carbapenems; Drug Resistance, Multiple, Bacterial; Female; Humans; Immunity, Innate; Klebsiella Infections; Klebsiella pneumoniae; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests

To investigate mechanisms for the decreased susceptibility to ceftazidime/avibactam in KPC-producing Klebsiella pneumoniae (KPC-KP).. A total of 24 isolates, 8 each with ceftazidime/avibactam MICs of 4-8, 1-2 and ≤0.5 mg/L, were randomly selected from 214 clinical isolates of KPC-KP, and the β-lactamase hydrolysis activity and porin expression profiles were determined. Plasmid profile and relative expression and copy number of the bla KPC gene were also analysed.. Ceftazidime/avibactam MIC 50 and MIC 90 were 2 and 4 mg/L, respectively, for the 214 KPC-KP isolates. The hydrolysis activities of nitrocefin and ceftazidime in both of the ceftazidime/avibactam MIC 4-8 and 1-2 mg/L groups were significantly higher than those of the MIC ≤0.5 mg/L group, while the hydrolysis activities were 4-4.6-fold higher in the MIC 4-8 mg/L group than in the other two groups when 4 mg/L avibactam was added. The relative expression and copy number of the bla KPC gene in the MIC 4-8 mg/L group were 4.2-4.8-fold higher than in the other two groups. Meanwhile, SDS-PAGE showed that all isolates in the two groups with MIC ≥1 mg/L lacked OmpK35, which had either an early frameshift with a premature stop codon ( n  =   15, ST11) or overexpression of the negative regulation genes, micF and ompR ( n  =   1, ST15), whereas OmpK35 and OmpK36 could both be observed in all isolates with MIC ≤0.5 mg/L.. Decreased ceftazidime/avibactam susceptibility in KPC-KP clinical isolates is caused by high ceftazidime hydrolysis activity and OmpK35 porin deficiency and the majority of isolates belong to ST11.

Topics: Azabicyclo Compounds; Bacterial Proteins; beta-Lactamase Inhibitors; beta-Lactamases; Ceftazidime; Drug Combinations; Electrophoresis, Polyacrylamide Gel; Humans; Hydrolysis; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Porins

Avibactam is a novel broad-range β-lactamase inhibitor active against Ambler class A (including ESBL and KPC) and some Ambler class C and D (e.g. OXA-48) enzymes. We here report on the emergence of ceftazidime/avibactam resistance in clinical, multiresistant, OXA-48 and CTX-M-14-producing Klebsiella pneumoniae isolate DT12 during ceftazidime/avibactam treatment.. Comparative whole-genome sequence analysis identified two SNPs in the CTX-M-14-encoding gene leading to two amino acid changes (P170S and T264I). Compared with WT CTX-M-14, expression of the CTX-M-14Δ170Δ264 isoform in Escherichia coli led to a >64- and 16-fold increase in ceftazidime and ceftazidime/avibactam MICs, respectively, functionally linking the observed SNPs and elevated MICs. The mutated CTX-M-14 isoform exhibited augmented ceftazidime hydrolytic activity, which was a reasonable cause for impaired susceptibility to avibactam inhibition. The P170S exchange in CTX-M-14 was found in association with elevated ceftazidime/avibactam MICs for independent K. pneumoniae isolates, but was not sufficient for full resistance. Apparently, additional CTX-M-independent mechanisms contribute to ceftazidime/avibactam resistance in K. pneumoniae DT12.. This study on the molecular basis of ceftazidime/avibactam resistance in clinical K. pneumoniae emerging in vivo underscores the need for continuous monitoring of ceftazidime/avibactam susceptibility during therapy. Despite sustained inhibition of OXA-48, rapid development of CTX-M-14 isoforms exhibiting augmented ceftazidime hydrolytic activity may limit the usefulness of ceftazidime/avibactam monotherapies in infections caused by isolates carrying blaCTX-M-14 and blaOXA-48.

Topics: Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamase Inhibitors; Ceftazidime; Drug Combinations; Drug Resistance, Multiple, Bacterial; Genome, Bacterial; High-Throughput Nucleotide Sequencing; Humans; Klebsiella Infections; Klebsiella pneumoniae; Male; Microbial Sensitivity Tests; Middle Aged

Topics: Azabicyclo Compounds; Bacterial Proteins; beta-Lactamases; Carbapenems; Ceftazidime; Drug Resistance, Bacterial; Humans; Klebsiella Infections; Klebsiella pneumoniae; Male; Metronidazole; Middle Aged; Pancreatic Diseases; Teicoplanin

Topics: Aged; Azabicyclo Compounds; Bacterial Proteins; beta-Lactam Resistance; beta-Lactamases; Carrier State; Ceftazidime; Drug Resistance, Multiple, Bacterial; Drug Therapy, Combination; Humans; Kidney Transplantation; Klebsiella Infections; Klebsiella pneumoniae; Male; Postoperative Complications; Rectum; Recurrence; Urinary Tract Infections

Previous in vivo studies using a human-simulated regimen of ceftaroline/avibactam 600/600mg every 8h (q8h) showed activity against extended-spectrum β-lactamase-, AmpC- and KPC-producing Enterobacteriaceae with minimum inhibitory concentrations (MICs) ≤ 1 μg/mL. Here we sought to determine the efficacy of this human-simulated regimen against organisms with MICs ≥ 1 μg/mL to help determine a breakpoint value that would reliability predict efficacy in humans. In total, 31 isolates (1 Escherichia coli, 9 Klebsiella pneumoniae, 9 Enterobacter cloacae, 1 Citrobacter koseri, 2 Serratia marcescens, 1 Klebsiella oxytoca and 8 Pseudomonas aeruginosa) with ceftaroline/avibactam MICs of 1 to 16 μg/mL were tested in a murine immunocompromised thigh infection model; 15 isolates were also tested in an immunocompetent model. Doses were given to simulate human free drug exposures of ceftaroline fosamil/avibactam 600/600 mg q8h over 24h as a 1-h infusion by targeting the fT>MIC profile. Efficacy was evaluated as the change in log10 CFU compared with 0-h controls after 24h. Reductions in bacterial CFU in the neutropenic model were seen against a majority of isolates tested with MICs ≤ 4 μg/mL, where fT>MIC was >55%. More variable efficacy was seen in isolates with MICs ≥ 8 μg/mL, where fT>MIC drops below 40%. Overall activity was enhanced in the immunocompetent model. The humanised regimen of ceftaroline fosamil/avibactam 600/600 mg q8h as a 1-h infusion showed predictable efficacy against isolates with various genotypic and phenotypic profiles and MICs ≤ 4 μg/mL. These data provide valuable information to help determine a ceftaroline/avibactam breakpoint for Enterobacteriaceae.

Topics: Animals; Anti-Bacterial Agents; Azabicyclo Compounds; beta-Lactamases; Ceftaroline; Cephalosporins; Disease Models, Animal; Enterobacter cloacae; Enterobacteriaceae; Enterobacteriaceae Infections; Escherichia coli; Female; Humans; Klebsiella Infections; Klebsiella pneumoniae; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections; Reproducibility of Results; Thigh

Secondary to the stability of aztreonam against metallo-β-lactamases, coupled with avibatam's neutralizing activity against often coproduced extended-spectrum β-lactamases (ESBLs) or AmpC enzymes, the combination of aztreonam and avibactam has been proposed as a principal candidate for the treatment of infections with metallo-β-lactamase-producing Gram-negative organisms. Using the neutropenic-mouse thigh infection model, we evaluated the efficacy of human simulated doses of aztreonam-avibactam and aztreonam against 14 Enterobacteriaceae and 13 Pseudomonas aeruginosa isolates, of which 25 produced metallo-β-lactamases. Additionally, six P. aeruginosa isolates were also evaluated in immunocompetent animals. A humanized aztreonam dose of 2 g every 6 h (1-h infusion) was evaluated alone and in combination with avibactam at 375 or 600 mg every 6 h (1-h infusion), targeting the percentage of the dosing interval in which free-drug concentrations remained above the MIC (fT>MIC). Efficacy was evaluated as the change in bacterial density after 24 h compared with the bacterial density at the initiation of dosing. Aztreonam monotherapy resulted in reductions of two of the Enterobacteriaceae bacterial isolates (aztreonam MIC, ≤ 32 μg/ml; fT>MIC, ≥ 38%) and minimal activity against the remaining isolates (aztreonam MIC, ≥ 128 μg/ml; fT>MIC, 0%). Alternatively, aztreonam-avibactam therapy resulted in the reduction of all 14 Enterobacteriaceae isolates (aztreonam-avibactam MICs, ≤16 μg/ml; fT>MIC, ≥ 65%) and no difference between the 375- and 600-mg doses of avibactam was noted. Similar pharmacodynamically predictable activity against P. aeruginosa was noted in studies with neutropenic and immunocompetent mice, with activity occurring when the MICs were ≤ 16 μg/ml and variable efficacy noted when the MICs were ≥ 32 μg/ml. Again, no difference in efficacy between the 375- and 600-mg doses of avibactam was observed. Aztreonam-avibactam represents an attractive treatment option for infections with metallo-β-lactamase-producing Gram-negative pathogens that coproduce ESBLs or AmpC.

Topics: Animals; Anti-Bacterial Agents; Azabicyclo Compounds; Aztreonam; Bacterial Proteins; beta-Lactamases; Enterobacteriaceae Infections; Escherichia coli; Escherichia coli Infections; Humans; Klebsiella Infections; Klebsiella pneumoniae; Mice; Microbial Sensitivity Tests; Pseudomonas aeruginosa; Pseudomonas Infections

New broad-spectrum β-lactamases such as KPC enzymes and CTX-M-15 enzymes threaten to markedly reduce the utility of our armamentarium of β-lactam agents, even our most potent drugs, such as carbapenems. NXL104 is a broad-spectrum non-β-lactam β-lactamase inhibitor. In this evaluation, we examined organisms carrying defined β-lactamases and identified doses and schedules of NXL104 in combination with the new cephalosporin ceftaroline, which would maintain good bacterial cell kill and suppress resistance emergence for a clinically relevant period of 10 days in our hollow-fiber infection model. We examined three strains of Klebsiella pneumoniae and one isolate of Enterobacter cloacae. K. pneumoniae 27-908M carried KPC-2, SHV-27, and TEM-1 β-lactamases. Its isogenic mutant, K. pneumoniae 4207J, was "cured" of the plasmid expressing the KPC-2 enzyme. K. pneumoniae 24-1318A carried a CTX-M-15 enzyme, and E. cloacae 2-77C expressed a stably derepressed AmpC chromosomal β-lactamase. Dose-ranging experiments for NXL104 administered as a continuous infusion with ceftaroline at 600 mg every 8 h allowed identification of a 24-h area under the concentration-time curve (AUC) for NXL104 that mediated bactericidal activity and resistance suppression. Dose fractionation experiments identified that "time > threshold" was the pharmacodynamic index linked to cell kill and resistance suppression. Given these results, we conclude that NXL104 combined with ceftaroline on an 8-hourly administration schedule would be optimal for circumstances in which highly resistant pathogens are likely to be encountered. This combination dosing regimen should allow for optimal bacterial cell kill (highest likelihood of successful clinical outcome) and the suppression of resistance emergence.

Topics: Anti-Bacterial Agents; Area Under Curve; Azabicyclo Compounds; Bacterial Proteins; beta-Lactamase Inhibitors; beta-Lactamases; Ceftaroline; Cephalosporins; Chromatography, Liquid; Drug Administration Schedule; Drug Dosage Calculations; Drug Resistance, Bacterial; Drug Synergism; Enterobacter cloacae; Enterobacteriaceae Infections; Humans; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Models, Biological; Tandem Mass Spectrometry

We evaluated the efficacy of NXL104, a novel β-lactamase inhibitor, in combination with ceftazidime (CAZ) in two murine infection models (septicemia and thigh infection). We chose two KPC-producing Klebsiella pneumoniae strains (VA-361 and VA-406) showing MICs of CAZ of ≥256 μg/ml. Septicemia was induced by the intraperitoneal injection of KPC-producing K. pneumoniae followed 30 min later by a single subcutaneous treatment with CAZ alone or CAZ-NXL104 in ratios of 2:1, 4:1, 8:1, and 16:1. In this model, the median effective doses for 50% (ED(50)) of the animals for CAZ alone versus VA-361 and VA-406 were 1,578 and 709 mg/kg of body weight, respectively. When combined with NXL104 at 2:1, 4:1, 8:1, and 16:1 ratios, the CAZ ED(50)s for VA-361 and VA-406 were reduced to 8.1 and 3.5 mg/kg, 15.1 and 3.8 mg/kg, 16.9 and 7.2 mg/kg, and 29.5 and 12.1 mg/kg, respectively. For thigh infection, neutropenia was induced by the intraperitoneal injection of cyclophosphamide at days -4 and -1 preinfection. Infection was established by the intramuscular injection of KPC-producing K. pneumoniae into the right thigh. Mice were treated 1.5 h postinfection with either CAZ alone or CAZ-NXL104 at constant ratios of 4:1. When thighs were removed at 24 h postinfection, a >2-log CFU reduction was observed for mice treated with CAZ-NXL104 at doses of ≥128:32 mg/kg. In contrast, CAZ doses of ≥1,024 mg/kg were unable to reduce the numbers of CFU. Despite resistance to CAZ and possessing a complex β-lactamase background, NXL104 combined with CAZ proved to be very effective in murine models of infection due to contemporary highly resistant KPC-producing K. pneumoniae isolates.

Topics: Animals; Anti-Bacterial Agents; Azabicyclo Compounds; Ceftazidime; Disease Models, Animal; Female; Klebsiella Infections; Klebsiella pneumoniae; Mice; Microbial Sensitivity Tests; Sepsis