scholarly journals Analysis of in vitro activity of cefiderocol against carbapenem resistant gram-negative bacilli by broth microdilution and disk diffusion method

2021 ◽  
Vol 58 ◽  
pp. 21003988
Author(s):  
Gayatree Nayak ◽  
Bijayini Behera ◽  
Srujana Mohanty, Punyatoya Kar
Keyword(s):  
Vitro Activity ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Gram Negative ◽  
Carbapenem Resistant

scholarly journals Cefepime/sulbactam as an enhanced antimicrobial combination therapy for the treatment of MDR Gram-negative infections

2019 ◽  
Author(s):  
David W Wareham ◽  
M H F Abdul Momin ◽  
Lynette M Phee ◽  
Michael Hornsey ◽  
Joseph F Standing
Keyword(s):  
Fixed Ratio ◽  
Vitro Activity ◽  
Definitive Treatment ◽  
High Dose ◽  
In Vitro Activity ◽  
Gram Negative ◽  
Pharmacodynamic Modelling ◽  
Carbapenem Resistant ◽  
Combination Regimens

Abstract Background β-Lactam (BL)/β-lactamase inhibitor (BLI) combinations are widely used for the treatment of Gram-negative infections. Cefepime has not been widely studied in combination with BLIs. Sulbactam, with dual BL/BLI activity, has been partnered with very few BLs. We investigated the potential of cefepime/sulbactam as an unorthodox BL/BLI combination against MDR Gram-negative bacteria. Methods In vitro activity of cefepime/sulbactam (1:1, 1:2 and 2:1) was assessed against 157 strains. Monte Carlo simulation was used to predict the PTA with a number of simulated cefepime combination regimens, modelled across putative cefepime/sulbactam breakpoints (≤16/≤0.25 mg/L). Results Cefepime/sulbactam was more active (MIC50/MIC90 8/8–64/128 mg/L) compared with either drug alone (MIC50/MIC90 128 to >256 mg/L). Activity was enhanced when sulbactam was added at 1:1 or 1:2 (P < 0.05). Reduction in MIC was most notable against Acinetobacter baumannii and Enterobacterales (MIC 8/8–32/64 mg/L). Pharmacokinetic/pharmacodynamic modelling highlighted that up to 48% of all isolates and 73% of carbapenem-resistant A. baumannii with a cefepime/sulbactam MIC of ≤16/≤8 mg/L may be treatable with a high-dose, fixed-ratio (1:1 or 1:2) combination of cefepime/sulbactam. Conclusions Cefepime/sulbactam (1:1 or 1:2) displays enhanced in vitro activity versus MDR Gram-negative pathogens. It could be a potential alternative to existing BL/BLI combinations for isolates with a cefepime/sulbactam MIC of 16/8 mg/L either as a definitive treatment or as a carbapenem-sparing option.

Ceftazidime – Avibactam susceptibility among carbapenem-resistant Enterobacterales in a pilot study in Turkey

2021 ◽  
Author(s):  
Hasan Selcuk Ozger ◽  
Ebru Evren ◽  
Serap Suzuk Yildiz ◽  
Cigdem Erol ◽  
Fatma Bayrakdar ◽  
...  
Keyword(s):  
Practical Method ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Drug Resistant ◽  
Chain Reaction ◽  
Disk Diffusion Method ◽  
Carbapenem Resistant ◽  
Therapeutic Choice ◽  
Polymerase Chain

AbstractThis study aimed to detect carbapenemase genes and to determine the in vitro susceptibility of Ceftazidime-Avibactam (CZA) in Enterobacterales isolates. Carbapenemase genes were detected by polymerase chain reaction. CZA sensitivity of isolates was evaluated with broth microdilution (BMD) and disk diffusion methods. A total of 318 carbapenem-resistant Enterobacterales isolates were included. Most of the isolates (n = 290, 91.2%) were identified as Klebsiella pneumoniae. The most common carbapenemase type was OXA-48 (n = 82, 27.6%). CZA susceptibility was evaluated in 84 isolates with OXA-48 and KPC carbapenemase activity. Both BMD and disk diffusion methods revealed that 95.2% of the isolates were sensitive to CZA; whereas, 4 (4.76%) isolates were resistant to CZA. Among colistin resistant isolates, 96.5% (n = 80) of them were susceptible to CZA. Our study demonstrated high in vitro efficacy of CZA in Enterobacterales isolates producing OXA-48 carbapenemase. High susceptibility rates against colistin resistant isolates which generally are also pan drug resistant, makes CZA a promising therapeutic choice for difficult-to-treat infections. Due to its high correlation with the BMD, disk diffusion method is a suitable and more practical method in detecting CZA in vitro activity.

Comparison of in vitro activities of plazomicin and other aminoglycosides against clinical isolates of Klebsiella pneumoniae and Escherichia coli

2021 ◽  
Author(s):  
Gizem İnce ◽  
Hasan Cenk Mirza ◽  
Aylin Üsküdar Güçlü ◽  
Hale Gümüş ◽  
Çiğdem Erol ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Resistance Rate ◽  
Vitro Activity ◽  
Diffusion Method ◽  
In Vitro Activity ◽  
Carbapenem Resistant ◽  
Gradient Diffusion ◽  
Susceptibility Rate

Abstract Objectives To compare the in vitro activity of plazomicin and two older aminoglycosides (gentamicin and amikacin) against 180 isolates of Escherichia coli and Klebsiella pneumoniae, including subsets of 60 non-ESBL-producing, 60 ESBL-producing and 60 carbapenem-resistant (46 carrying blaOXA-48, 11 carrying blaNDM and 3 carrying blaOXA-48 and blaNDM) strains. Methods MICs of plazomicin, gentamicin and amikacin were determined by a gradient diffusion method. Gentamicin and amikacin MICs were interpreted according to CLSI criteria and EUCAST breakpoint tables. Plazomicin MICs were interpreted using FDA-defined breakpoints. Results All non-ESBL-producing and ESBL-producing isolates were susceptible to plazomicin. The plazomicin susceptibility rate (71.7%) in carbapenem-resistant isolates was significantly higher than those observed for gentamicin (45%) and amikacin (56.7% and 51.7% according to CLSI and EUCAST breakpoints, respectively). Gentamicin, amikacin and plazomicin susceptibility rates (35.6% for gentamicin; 44.4% and 37.8% for amikacin according to CLSI and EUCAST breakpoints, respectively; 64.4% for plazomicin) in carbapenem-resistant K. pneumoniae were significantly lower than those observed for carbapenem-resistant E. coli isolates (73.3% for gentamicin; 93.3% for amikacin and plazomicin). Gentamicin, amikacin and plazomicin susceptibility rates for blaNDM-positive isolates were lower than those observed for blaOXA-48-positive isolates, but differences were not statistically significant. Among the isolates that were non-susceptible to both gentamicin and amikacin, the plazomicin susceptibility rate was less than 30%. Conclusions Although plazomicin showed excellent in vitro activity against carbapenem-susceptible isolates, the plazomicin resistance rate increased to 35.6% among carbapenem-resistant K. pneumoniae and further increased to 45.5% among blaNDM-positive isolates.

Evaluation of the in vitro activity of new polymyxin B analogue SPR206 against clinical MDR, colistin-resistant and tigecycline-resistant Gram-negative bacilli

2020 ◽  
Vol 75 (9) ◽  
pp. 2609-2615 ◽  
Author(s):  
Yawei Zhang ◽  
Chunjiang Zhao ◽  
Qi Wang ◽  
Xiaojuan Wang ◽  
Hongbin Chen ◽  
...  
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Enterobacter Cloacae ◽  
Polymyxin B ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Gram Negative ◽  
Carbapenem Resistant ◽  
Resistant Strains

Abstract Background SPR206 is a novel polymyxin analogue. Activity against clinical isolates is little documented. Methods A collection of 200 MDR, carbapenem-resistant, tigecycline-resistant, colistin-resistant and non-MDR clinical isolates of Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae and Stenotrophomonas maltophilia was obtained from 50 centres across China (2016–17). All isolates were derived from respiratory tract, urine and blood samples. Strains were purposely selected on the basis of phenotypes, genotypes and specimen origins. MICs of SPR206 and other antimicrobials were determined. Results SPR206 was active against all bacteria tested except colistin-resistant isolates. The MIC50/90 values of SPR206 for colistin-resistant strains were comparable to known polymyxins (16/128 versus 8/128 mg/L). SPR206 exhibited potent activity against colistin-susceptible OXA-producing A. baumannii (MIC50/90 = 0.064/0.125 mg/L), NDM-producing Enterobacteriaceae (MIC50/90 = 0.125/0.25 mg/L) and KPC-2-producing Enterobacteriaceae (MIC50/90 = 0.125/0.5 mg/L). In fact, SPR206 was the most potent agent tested, with 2- to 4-fold lower MICs than colistin and polymyxin B for A. baumannii, P. aeruginosa and Enterobacteriaceae. Additionally, MIC values of SPR206 (MIC50/90 = 0.064/0.125 mg/L) were 16- to 32-fold lower than those of tigecycline (MIC50/90 = 2/2 mg/L) for tigecycline-susceptible carbapenem-resistant A. baumannii. Conclusions SPR206 showed good in vitro activity against MDR, tigecycline-resistant and non-MDR clinical isolates of Gram-negative pathogens. SPR206 also exhibited superior potency to colistin and polymyxin B, with 2- to 4-fold lower MIC50/90 values.

scholarly journals Evaluation of Etests and the disk diffusion method for assessment of the activity of ceftazidime-avibactam against Enterobacterales and Pseudomonas aeruginosa in China

2020 ◽  
Author(s):  
Qi Wang ◽  
Feifei Zhang ◽  
Zhanwei Wang ◽  
Hongbin Chen ◽  
Xiaojuan Wang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Random Selection ◽  
Alternative Methods ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Antimicrobial Susceptibility Test ◽  
Disk Diffusion Method ◽  
Gram Negative ◽  
Selection Group

Abstract Background: Gram-negative bacilli, particularly Enterobacterales and Pseudomonas aeruginosa, often acquire antimicrobial resistance. Ceftazidime-avibactam was approved for use in China in 2019. However, currently available commercial antimicrobial susceptibility test kits have not yet been developed. Here, we evaluated the Etest and disk diffusion method for assessment of the efficacy of ceftazidime-avibactam against Enterobacterales and P. aeruginosa in China. Results: In total, 194 Enterobacterales and 77 P. aeruginosa isolates, which were divided into a random selection group (140 Enterobacterales and 54 P. aeruginosa isolates) and a stock group (46 Enterobacterales and 31 P. aeruginosa isolates), were assessed by the Etest, disk diffusion, and broth microdilution (BMD) methods. Minimum inhibitory concentrations (MICs) and zone diameters were interpreted according to the CLSI M100 30th edition. For all 271 Enterobacterales and P. aeruginosa isolates, no very major errors were found using Etests. The overall categorical agreement rates (CA%) of Etests for Enterobacterales and P. aeruginosa were 99.5% (193/194) and 96.1% (74/77), respectively. The overall essential agreement rates (EA%) of Etests for Enterobacterales and P. aeruginosa were 95.9% (186/194) and 94.8% (73/77), respectively. In both the random selection and stock groups, EA% and CA% values of Etests exceeded 90%. Overall CA% values of the disk diffusion method for Enterobacterales and P. aeruginosa were 98.5% (191/194) and 93.5% (71/77), respectively. There was no linear relationship between zone diameter and BMD MIC. Conclusions: For Enterobacterales and P. aeruginosa, Etests and the disk diffusion method could have better performance as alternative methods to meet the needs of clinical treatment interpretation. Application of the disk diffusion method in Enterobacterales was superior to that in P. aeruginosa.

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