#Ceftazidime – #avibactam to treat life-threatening #infections from #carbapenem #resistant #pathogens in critically ill mechanically ventilated patients (Antimicrob Agents Chemother., abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Ceftazidime-avibactam to treat life-threatening infections from carbapenem resistant pathogens in critically ill mechanically ventilated patients

Vasiliki Tsolaki, Konstantinos Mantzarlis, Athanasios Mpakalis, Ergina Malli, Fotios Tsimpoukas, Athanasia Tsirogianni, Konstantinos Papagiannitsis, Paris Zygoulis, Maria-Eirini Papadonta, Efthimia Petinaki, Demosthenes Makris, Epaminondas Zakynthinos

DOI: 10.1128/AAC.02320-19



Data on the effectiveness of ceftazidime-avibactam (CAZ-AVI) in critically ill, mechanically ventilated patients are limited. The present retrospective observational cohort study, which was conducted in two general Intensive Care Units (ICUs) in central Greece, compared critically-ill, mechanically ventilated patients suffering from carbapenem-resistant enterobacteriaceae (CRE) infections receiving CAZ-AVI to patients who received appropriate available antibiotic therapy. Clinical, microbiological outcomes and safety issues were evaluated. A secondary analysis in patients with blood stream infections (BSI) was conducted. Forty-one patients that received CAZ-AVI (CAZ-AVI group) were compared to thirty-six patients receiving antibiotics other than CAZ-AVI (control group). There was significant improvement in the SOFA score on Day 4 and 10 in the CAZ-AVI compared to the control group (p=0.006, and p=0.003 respectively). Microbiological eradication was accomplished in 33/35 (94.3%) in CAZ-AVI group vs 21/31 (67.7%) patients in control group (p=0.021) and clinical cure was observed in 33/41 (80.5%) vs 19/36 (52.8%) patients (p=0.010), respectively. The results were similar in BSI subgroups for both outcomes (p=0.038 and p=0.014, respectively). 28-day survival was 85.4% in the CAZ-AVI and 61.1% in the control group (log Rank=0.035), while there were 2 and 12 relapses in each group (p=0.042). A CAZ-AVI containing regime was independent predictor of survival and clinical cure (OR 5.575, p=0.012 and OR 5.125, p=0.004, respectively) along with illness severity. In conclusion, no significant side effects were reported. A CAZ-AVI containing regime is more effective than other available antibiotic agents for the treatment of CRE infections in the high-risk, mechanically-ventilated, ICU population.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Enterobacteriaceae; Ceftazidime; Avibactam; Intensive care.


Successful rescue #treatment of #sepsis due to a #PDR, #NDM-producing #Klebsiella pneumoniae using #aztreonam powder for nebulizer solution as IV therapy in combination with #ceftazidime/avibactam (J Antimicrob Chemother., summary)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Summary, edited.]

Successful rescue treatment of sepsis due to a pandrug-resistant, NDM-producing Klebsiella pneumoniae using aztreonam powder for nebulizer solution as intravenous therapy in combination with ceftazidime/avibactam

Elske Sieswerda, Marre van den Brand, Roland B van den Berg, Joris Sträter, Leo Schouls, Karin van Dijk, Andries E Budding

Journal of Antimicrobial Chemotherapy, dkz495, https://doi.org/10.1093/jac/dkz495

Published: 02 December 2019



Pandrug-resistant Klebsiella pneumoniae that produces New Delhi MBL (NDM) is increasingly reported worldwide.1 These strains contain multiple β-lactamase genes but also may have acquired resistance to last-resort options such as colistin and tigecycline. Combining aztreonam and avibactam is potentially effective in MDR, NDM-producing Enterobacterales.2 Avibactam inhibits class A, C and D ESBLs, cephalosporinases and carbapenemases, while aztreonam is stable to hydrolysis by class B MBLs such as NDM. Until this drug combination becomes available, one could combine aztreonam and ceftazidime/avibactam to treat serious infections with such strains. A small number of studies have reported on 13 patients with serious infections with NDM-producing Enterobacterales who were successfully treated with aztreonam and ceftazidime/avibactam.3–7 Evidence of clinical efficacy and safety is therefore limited at present. Also, aztreonam for IV use is not registered and readily available in many countries, including the Netherlands. We describe successful rescue treatment of a patient with sepsis due to a pandrug-resistant, NDM-producing K. pneumoniae using aztreonam powder for nebulizer solution as IV therapy in combination with ceftazidime/avibactam.




We presented this study in March 2019 at the Scientific Spring Meeting 2019 from the Dutch Society of Medical Microbiology, Arnhem, the Netherlands.


This study was carried out as part of our routine work.

Transparency declarations

None to declare.

Keywords: Antibiotics; Drugs Resistance; NDM; Klebsiella pneumoniae; Sepsis; Aztreonam; Ceftazidime; Avibactam.


In vitro activity of #ceftazidime / #avibactam against isolates of #carbapenem-non-susceptible #Enterobacteriaceae collected during the INFORM global surveillance programme (2015–17) (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

In vitro activity of ceftazidime/avibactam against isolates of carbapenem-non-susceptible Enterobacteriaceae collected during the INFORM global surveillance programme (2015–17)

Iris Spiliopoulou, Krystyna Kazmierczak, Gregory G Stone

Journal of Antimicrobial Chemotherapy, dkz456, https://doi.org/10.1093/jac/dkz456

Published: 19 November 2019




To report data for ceftazidime/avibactam and comparators against meropenem-non-susceptible Enterobacteriaceae collected globally (excluding centres in the USA) from 2015 to 2017 as part of the International Network For Optimal Resistance Monitoring (INFORM) surveillance programme.


MICs and susceptibility were determined using EUCAST broth microdilution methodology and EUCAST breakpoints. Isolates were screened to detect genes encoding β-lactamases using multiplex PCR assays. MBL-positive isolates were those in which one or more of the IMP, VIM and/or NDM genes were detected.


A total of 1460 meropenem-non-susceptible isolates were collected and, of the agents on the panel, susceptibility was highest to ceftazidime/avibactam, colistin and tigecycline [73.0%, 77.0% (1081/1403) and 78.1%, respectively]. Ceftazidime/avibactam was not active against MBL-positive isolates (n = 367); these isolates showed the highest rates of susceptibility to colistin (92.1%, 303/329), tigecycline (71.9%) and amikacin (46.6%). A total of 394 isolates were resistant to ceftazidime/avibactam and, of the 369 isolates that were screened, 98.4% were found to carry a gene encoding an MBL enzyme. Among isolates that were identified as carbapenemase positive and MBL negative (n = 910), susceptibility was highest to ceftazidime/avibactam (99.8%). Susceptibility was also highest to ceftazidime/avibactam among isolates that were carbapenemase negative and MBL negative (94/98, 95.9%).


These data highlight the need for continued surveillance of antimicrobial activity as well as the need for new antimicrobials to treat infections caused by meropenem-non-susceptible Enterobacteriaceae, for which the options are extremely limited.

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Enterobacteriaceae; Avibactam; Ceftazidime.


Searching for the Optimal #Treatment for Metallo- and Serine-β-Lactamase Producing #Enterobacteriaceae: #Aztreonam in Combination with #Ceftazidime-avibactam or #Meropenem-vaborbactam (AAC, abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Searching for the Optimal Treatment for Metallo- and Serine-β-Lactamase Producing Enterobacteriaceae: Aztreonam in Combination with Ceftazidime-avibactam or Meropenem-vaborbactam

M Biagi, T Wu, M Lee, S Patel, D Butler, E Wenzler

DOI: 10.1128/AAC.01426-19




Metallo-β-lactamase (MBL)-producing Enterobacteriaceae, particularly those that co-harbor serine β-lactamases, are a serious emerging public health threat given their rapid dissemination and the limited number of treatment options. Pre-clinical and anecdotal clinical data support the use of aztreonam in combination with ceftazidime-avibactam against these pathogens, but other aztreonam-based combinations have not been explored. The objective of this study was to evaluate the in vitro activity and compare synergy between aztreonam in combination with ceftazidime-avibactam and meropenem-vaborbactam against serine and MBL-producing Enterobacteriaceae via time-kill analyses.


8 clinical Enterobacteriaceae strains (4 Escherichia coli and 4 Klebsiella pneumoniae) co-producing NDM and at least one serine β-lactamase were used for all experiments. Drugs were tested alone, in dual β-lactam combinations, and in triple drug combinations against all strains.


All strains were resistant to ceftazidime-avibactam and meropenem-vaborbactam and 7/8 (87.5%) strains were resistant to aztreonam. Aztreonam combined with ceftazidime-avibactam was synergistic against all 7 aztreonam-resistant strains. Aztreonam combined with meropenem-vaborbactam was synergistic against all aztreonam-resistant strains with the exception of an OXA-232-producing K. pneumoniae strain. Neither triple combination was synergistic against the aztreonam-susceptible strain. Likewise, neither dual β-lactam combination was synergistic against any strain.


These data suggest that aztreonam plus meropenem-vaborbactam has similar activity to aztreonam plus ceftazidime-avibactam against Enterobacteriaceae producing NDM and other non-OXA-48-like serine β-lactamases. Confirmation of these findings in future in vitro and in vivo models is warranted.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Antibiotics; Drugs Resistance; Beta-lactams; NDM; Aztreonam; Meropenem; Vaborbactam; Ceftazidime; Avibactam; Enterobacteriaceae.


#Cost-effectiveness of #ceftazidime – #avibactam for #treatment of #carbapenem – resistant #Enterobacteriaceae  #bacteremia and #pneumonia (Antimicrob Agents Chemother., abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Cost-effectiveness of ceftazidime-avibactam for treatment of carbapenem-resistant Enterobacteriaceae bacteremia and pneumonia

Matthew S. Simon [MD, MS], Maroun M. Sfeir [MD, MPH], David P. Calfee [MD, MS], Michael J. Satlin [MD, MS]

DOI: 10.1128/AAC.00897-19




Ceftazidime/avibactam (CAZ-AVI) may improve outcomes among patients with carbapenem-resistant Enterobacteriaceae (CRE) infections compared to conventional therapies. However, CAZ-AVI’s cost-effectiveness is unknown.


We used a decision analytic model to estimate the health and economic consequences of CAZ-AVI-based therapy compared to colistin-based therapy (COL) for a hypothetical cohort of patients with CRE pneumonia or bacteremia over a 5-year horizon. Model inputs were from published sources and included CRE mortality with COL (41%), CAZ-AVI’s absolute risk reduction in CRE mortality (23%), daily cost of CAZ-AVI ($926), risk of nephrotoxicity with COL (42%) and probability of discharge to long-term care (LTC) following CRE infection (56%). Outcomes included quality adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICER; $/QALY). 1-way and probabilistic sensitivity analyses were performed and ICERs were compared to willingness to pay standards of $100,000/QALY and $150,000/QALY.


In the base case, CAZ-AVI had an ICER of $95,000/QALY. At a $100,000/QALY threshold, results were sensitive to a number of variables including: the probability and cost of LTC, quality of life following CRE infection, CAZ-AVI’s absolute risk reduction in mortality, all-cause mortality, daily cost of CAZ-AVI, and healthcare costs after CRE infection. The ICER did not exceed $150,000/QALY after varying all model inputs across a wide range of plausible values. In probabilistic sensitivity analysis, CAZ-AVI was the optimal strategy in 59% and 99% of simulations at $100,000/QALY and $150,000/QALY threshold, respectively.


CAZ-AVI is a cost-effective treatment for CRE bacteremia and pneumonia based on accepted willingness to pay standards in the US.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Enterobacteriaceae; Ceftazidime; Avibactam; Bacteremia; Pneumonia; USA.


#Phenotypic, biochemical and #genetic analysis of #KPC-41, a KPC-3 variant conferring #resistance to #ceftazidime-avibactam and exhibiting reduced #carbapenemase activity (Antimicrob Agents Chemother., abstract)

[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]

Phenotypic, biochemical and genetic analysis of KPC-41, a KPC-3 variant conferring resistance to ceftazidime-avibactam and exhibiting reduced carbapenemase activity

Linda Mueller, Amandine Masseron, Guy Prod’Hom, Tatiana Galperine, Gilbert Greub, Laurent Poirel, Patrice Nordmann

DOI: 10.1128/AAC.01111-19



A novel KPC variant, KPC-41, was identified in a Klebsiella pneumoniae clinical isolate from Switzerland. This ß-lactamase possessed a three amino-acid insertion (Pro-Asn-Lys) located between amino acids 269 and 270 compared to the KPC-3 amino acid sequence. Cloning and expression of the blaKPC-41 gene in Escherichia coli, followed by determination of MIC values and kinetic parameters, showed that KPC-41, compared to KPC-3, has an increased affinity to ceftazidime and a decreased sensitivity to avibactam, leading to resistance to ceftazidime-avibactam once produced in K. pneumoniae. Furthermore, KPC-41 exhibited a drastic decrease of its carbapenemase activity. This report highlights that a diversity of KPC variants conferring resistance to ceftazidime-avibactam already circulate in Europe.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Antibiotics; Drugs Resistance; Klebsiella pneumoniae; Ceftazidime; Avibactam.


An in situ high-throughput screen identifies #inhibitors of intracellular #Burkholderia pseudomallei with therapeutic efficacy (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

An in situ high-throughput screen identifies inhibitors of intracellular Burkholderia pseudomallei with therapeutic efficacy

Philip L. Bulterys, Isabelle J. Toesca, Michael H. Norris, Jeffrey P. Maloy, Sorel T. Fitz-Gibbon, Bryan France, Babak Toffig, Marco Morselli, Nawarat Somprasong, Matteo Pellegrini, Herbert P. Schweizer, Apichai Tuanyok, Robert Damoiseaux, Christopher T. French, and Jeff F. Miller

PNAS first published August 22, 2019 / DOI: https://doi.org/10.1073/pnas.1906388116

Contributed by Jeff F. Miller, July 13, 2019 (sent for review April 15, 2019; reviewed by Yunn-Hwen Gan and John J. Mekalanos)



Burkholderia pseudomallei, the etiologic agent of melioidosis, is an environmental organism that inhabits tropical soils and kills an estimated 90,000 people each year. Caused by an intracellular and often drug-resistant pathogen, melioidosis is notoriously difficult to treat, with mortality rates approaching 50% in some settings despite appropriate diagnosis and clinical management. Using a high-throughput, cell-based phenotypic screen we have discovered 2 antibiotic candidates with improved in vivo efficacy compared to the current standard of care: a fluoroquinolone analog, burkfloxacin, and an FDA-approved antifungal drug, flucytosine. As a widely used antifungal with a well-known safety profile, the potential to repurpose flucytosine for treating melioidosis may represent a rapid route to clinical translation.



Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) are Tier-1 Select Agents that cause melioidosis and glanders, respectively. These are highly lethal human infections with limited therapeutic options. Intercellular spread is a hallmark of Burkholderia pathogenesis, and its prominent ties to virulence make it an attractive therapeutic target. We developed a high-throughput cell-based phenotypic assay and screened ∼220,000 small molecules for their ability to disrupt intercellular spread by Burkholderia thailandensis, a closely related BSL-2 surrogate. We identified 268 hits, and cross-species validation found 32 hits that also disrupt intercellular spread by Bp and/or Bm. Among these were a fluoroquinolone analog, which we named burkfloxacin (BFX), which potently inhibits growth of intracellular Burkholderia, and flucytosine (5-FC), an FDA-approved antifungal drug. We found that 5-FC blocks the intracellular life cycle at the point of type VI secretion system 5 (T6SS-5)-mediated cell–cell spread. Bacterial conversion of 5-FC to 5-fluorouracil and subsequently to fluorouridine monophosphate is required for potent and selective activity against intracellular Burkholderia. In a murine model of fulminant respiratory melioidosis, treatment with BFX or 5-FC was significantly more effective than ceftazidime, the current antibiotic of choice, for improving survival and decreasing bacterial counts in major organs. Our results demonstrate the utility of cell-based phenotypic screening for Select Agent drug discovery and warrant the advancement of BFX and 5-FC as candidate therapeutics for melioidosis in humans.

Burkholderia pseudomallei  – melioidosis – type 6 secretion system (T6SS) – small molecule – drug discovery

Keywords: Antibiotics; Burkholderia pseudomallei; Melioidosis; Burkfloxacin; Flucytosine.