In vitro fosfomycin study on concordance of susceptibility testing methods against ESBL and carbapenem-resistant Enterobacteriaceae

ABSTRACT Meropenem-vaborbactam is a new agent with the potential to treat carbapenem-resistant Enterobacteriaceae (CRE) infections. We describe the in vitro activity of meropenem-vaborbactam against representative CRE genotypes and laboratory-engineered Escherichia coli isolates harboring mutant blaKPC genes associated with ceftazidime-avibactam resistance. We also compared disk diffusion and gradient strip testing methods to standard broth microdilution methods. Against 120 CRE isolates, median ceftazidime-avibactam and meropenem-vaborbactam MICs were 1 and 0.03 µg/ml, respectively. Ninety-eight percent (117/120) of isolates were susceptible to meropenem-vaborbactam (MICs ≤ 4 µg/ml). Against Klebsiella pneumoniae isolates harboring mutant blaKPC, the addition of vaborbactam lowered the meropenem MICs in 78% of isolates (14/18); 100% were susceptible to meropenem-vaborbactam. Median meropenem-vaborbactam MICs were higher against K. pneumoniae carbapenemase (KPC)-producing K. pneumoniae isolates with mutant ompK36 porin genes (n = 26) than against those with wild-type ompK36 porin genes (n = 54) (0.25 versus 0.03 µg/ml; P < 0.0001). Against E. coli TOP10 isolates with plasmid constructs containing wild-type blaKPC or mutant blaKPC, the addition of vaborbactam at 8 µg/ml lowered the meropenem MICs 2- to 512-fold, resulting in meropenem-vaborbactam MICs of 0.03 µg/ml. The rates of categorical agreement with broth microdilution for disk diffusion or gradient strips ranged from 90 to 95%. Essential agreement rates were higher for research-use-only (RUO) gradient strips manufactured by bioMérieux (82%) than for those manufactured by Liofilchem (48%) (P < 0.0001). Taken together, our data highlight the potent in vitro activity of meropenem-vaborbactam against CRE, including isolates resistant to ceftazidime-avibactam. Vaborbactam inhibited both wild-type and variant KPC enzymes. On the other hand, KPC-producing K. pneumoniae isolates with ompK36 mutations displayed higher meropenem-vaborbactam MICs than isolates with wild-type ompK36. The results of susceptibility testing with RUO bioMérieux gradient strips most closely aligned with those of broth microdilution methods.

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Comparative Evaluation of Seven Tigecycline Susceptibility Testing Methods for Carbapenem-Resistant Enterobacteriaceae

Infection and Drug Resistance ◽

10.2147/idr.s289499 ◽

2021 ◽

Vol Volume 14 ◽

pp. 1511-1516

Author(s):

Hongling Li ◽

Mao Zhou ◽

Xia Chen ◽

Yawen Zhang ◽

Zijuan Jian ◽

...

Keyword(s):

Comparative Evaluation ◽

Susceptibility Testing ◽

Testing Methods ◽

Carbapenem Resistant ◽

Carbapenem Resistant Enterobacteriaceae

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In Vitro Susceptibility Testing of Essential Oils Against Carbapenem-Resistant Enterobacteriaceae and Selected ATCC Strains

Open Forum Infectious Diseases ◽

10.1093/ofid/ofw172.1601 ◽

2016 ◽

Vol 3 (suppl_1) ◽

Cited By ~ 1

Author(s):

Jan E. Patterson ◽

Jose Cadena ◽

Kristi Traugott ◽

Cynthia Kelly ◽

Steven Dallas

Keyword(s):

Essential Oils ◽

Susceptibility Testing ◽

In Vitro Susceptibility ◽

Carbapenem Resistant ◽

In Vitro Susceptibility Testing ◽

Carbapenem Resistant Enterobacteriaceae

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Faculty Opinions recommendation of In vitro activity of plazomicin against β-lactamase-producing carbapenem-resistant Enterobacteriaceae (CRE).

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.732040662.793555347 ◽

2019 ◽

Author(s):

Richard Watkins

Keyword(s):

Vitro Activity ◽

In Vitro Activity ◽

Carbapenem Resistant ◽

Carbapenem Resistant Enterobacteriaceae

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Enterobacteriaceae isolates carrying the New Delhi metallo-β-lactamase gene in Yemen

Journal of Medical Microbiology ◽

10.1099/jmm.0.073767-0 ◽

2014 ◽

Vol 63 (10) ◽

pp. 1316-1323 ◽

Cited By ~ 24

Author(s):

Alima Gharout-Sait ◽

Samer-Ahmed Alsharapy ◽

Lucien Brasme ◽

Abdelaziz Touati ◽

Rachida Kermas ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Susceptibility Testing ◽

Enterobacter Cloacae ◽

New Delhi ◽

Carbapenem Resistant ◽

Genes Encoding ◽

Phenotypic Tests ◽

Lactamase Gene ◽

Sequence Types

Ten carbapenem-resistant Enterobacteriaceae (eight Klebsiella pneumoniae isolates and two Enterobacter cloacae) isolates from Yemen were investigated using in vitro antimicrobial susceptibility testing, phenotypic carbapenemase detection, multilocus sequence typing (MLST) and replicon typing. Carbapenemase, extended-spectrum β-lactamase (ESBL) and plasmid-mediated quinolone resistance determinant genes were identified using PCR and sequencing. All of the 10 carbapenem-resistant Enterobacteriaceae were resistant to β-lactams, tobramycin, ciprofloxacin and cotrimoxazole. Imipenem, doripenem and meropenem MICs ranged from 2 to >32 mg l−1 and ertapenem MICs ranged from 6 to >32 mg l−1. All of the K. pneumoniae isolates showed ESBL activity in phenotypic tests. Genes encoding bla NDM were detected in all strains. All K. pneumoniae strains produced CTX-M-15 ESBL and SHV β-lactamases. TEM-1 β-lactamase was detected in seven isolates. Nine isolates were qnr positive including QnrB1, QnrA1 and QnrS1, and six isolates produced AAC-6′-Ib-cr. MLST identified five different sequence types (STs): ST1399, ST147, ST29, ST405 and ST340. Replicon typing showed the presence of IncFII1K plasmids in four transformants. To the best of our knowledge, this is the first report of NDM-1-producing Enterobacteriaceae isolates in Yemen.

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Performance of ceftazidime/avibactam susceptibility testing methods against clinically relevant Gram-negative organisms

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dky483 ◽

2018 ◽

Vol 74 (3) ◽

pp. 633-638 ◽

Cited By ~ 1

Author(s):

E Wenzler ◽

M Lee ◽

T J Wu ◽

K A Meyer ◽

R K Shields ◽

...

Keyword(s):

Susceptibility Testing ◽

Drug Application ◽

Error Rates ◽

Testing Methods ◽

Suitable Alternative ◽

Gram Negative ◽

Treatment Regimens ◽

Carbapenem Resistant ◽

Gram Negative Organisms ◽

New Drug Application

Abstract Objectives To ensure the accuracy of susceptibility testing methods for ceftazidime/avibactam. Methods The performances of the Etest (bioMérieux), 30/20 μg disc (Hardy diagnostics) and 10/4 μg disc (Mast Group) were evaluated against the reference broth microdilution (BMD) method for 102 clinically relevant Gram-negative organisms: 69 ceftazidime- and meropenem-resistant Klebsiella pneumoniae and 33 MDR non-K. pneumoniae. Essential and categorical agreement along with major and very major error rates were determined according to CLSI guidelines. Results A total of 78% of isolates were susceptible to ceftazidime/avibactam. None of the three methods met the defined equivalency threshold against all 102 organisms. The Etest performed the best, with categorical agreement of 95% and major errors of 6.3%. Against the 69 ceftazidime- and meropenem-resistant K. pneumoniae, only the Etest and the 10/4 μg disc met the equivalency threshold. None of the three methods met equivalency for the 33 MDR isolates. There were no very major errors observed in any analysis. These results were pooled with those from a previous study of 74 carbapenem-resistant Enterobacteriaceae and data from the ceftazidime/avibactam new drug application to define optimal 30/20 μg disc thresholds using the error-rate bound model-based approaches of the diffusion breakpoint estimation testing software. This analysis identified a susceptibility threshold of ≤19 mm as optimal. Conclusions Our data indicate that the Etest is a suitable alternative to BMD for testing ceftazidime/avibactam against ceftazidime- and meropenem-resistant K. pneumoniae. The 30/20 μg discs overestimate resistance and may lead to the use of treatment regimens that are more toxic and less effective.

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621. In vitro Ceftazidime: Avibactam Resistance in Carbapenem-Resistant Enterobacteriaceae Isolates

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.689 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S288-S289

Author(s):

Maymonah Belal ◽

Lori Villasis ◽

Elizabeth Diago-Navarro ◽

Michael Motley ◽

Allen Young; Eric Spitzer ◽

...

Keyword(s):

Resistant Isolate ◽

Ventilator Associated Pneumonia ◽

Repeated Testing ◽

Klebsiella Species ◽

Carbapenem Resistant ◽

Strain Collection ◽

Enterobacter Species ◽

Resistant Strains ◽

Carbapenem Resistant Enterobacteriaceae

Abstract Background Ceftazidime–avibactam (CAZ-AVI) is a new antibiotic with activity against many Carbapenem-resistant Enterobacteriaceae (CRE). Although CAZ-AVI resistance in CRE has been reported, it is not consistently assessed. Our study aimed to assess the prevalence of CAZ-AVI resistance in CRE isolated from patients with and without prior exposure to CAZ-AVI. Methods We tested 116 CRE isolates for CAZ-AVI resistance by Kirby–Bauer (KB) disk diffusion susceptibility. Resistant isolates were verified by repeat KB and E-test performed by the Stony Brook Hospital laboratory. The blaKPC gene of resistant strains was amplified by PCR and sequenced. Patient data were used to determine whether patients were colonized or infected, and whether they were exposed to CAZ-AVI. Results Of the 116 CRE isolates from 86 patients (96 encounters), 50% were Klebsiella species, 23.2% were Enterobacter species, 10.3% Escherichia coli and 16.5% other CRE. They were recovered from colonized (37%) and infected (63%) patients of which 18% were treated with CAZ-AVI during their hospitalizations (median duration of therapy, 6 days). Two CRE isolates (1.7%) were found to be resistant on repeated testing. One isolate was K. pneumoniae derived from the sputum of a patient diagnosed with ventilator-associated pneumonia who received 40 days of CAZ-AVI therapy prior to isolation of the resistant isolate (KB diameter 20 mm, MIC > 512 μg/mL by E-Test). Sequencing of the strain’s blaKPC3 gene revealed a previously described Ambler-position D179Y mutation that has been shown to convey resistance. The second CAZ-AVI-resistant K. pneumoniae (KB diameter 19 mm, MIC 64 μg/mL by E-test) was isolated from the urine of a colonized patient naïve to CAZ-AVI therapy. The strain’s blaKPC10 gene had no mutations. Conclusion In our strain collection, the rate of resistance to CAZ-AVI remains low <2%. Although we found one mutation (D179Y) previously linked to CAZ-AVI resistance we also discovered one K. pneumoniae isolate with in vitro resistance to CAZ-AVI that did not exhibit any blaKPC mutations conveying CAZ-AVI resistance. Interestingly, this strain was derived from a patient with no prior CAZ-AVI exposure. Whole-genome sequencing will be performed to identify other genes or mutations that may confer resistance. Disclosures All authors: No reported disclosures.

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532. Can Saccharomyces boulardii Therapy Be Effective in Decolonizing Rectal Carbapenem-Resistant Enterobacteriaceae (CRE) Colonization?

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.601 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S255-S256

Author(s):

Oguz Resat Sipahi ◽

Gunel Quliyeva ◽

Feriha Cilli ◽

Nilgun Deniz Kucukler ◽

Demet Dikis ◽

...

Keyword(s):

Susceptibility Testing ◽

Rectal Swab ◽

Saccharomyces Boulardii ◽

Inclusion Criteria ◽

Randomized Controlled ◽

Promising Tool ◽

Carbapenem Resistant ◽

History Of ◽

Vitek 2 ◽

Carbapenem Resistant Enterobacteriaceae

Abstract Background CRE are globally important pathogens associated with significant morbidity and mortality. The problem of carrying CRE may continue to create a problem in discharged cases in the community. Saccharomyces boulardii sachet therapy (SBST) is reported to cause decolonization in several MDR bacteria carriers. Herein, it is aimed to present the decolonizing rates of rectal CRE colonized cases after SBST treatment. Methods The study period was August 2018–March 2019. Inclusion criteria were: (i) age >18, (ii) receiving Saccharomyces boulardii 250 mg sachets q12h for 7 days, (iii) being proven CRE carrier on rectal swab culture (RSC) up to 5 days period before SBST. The first repeated RSC was performed 3–5 days after the end of SBST. Data were retrieved from the hospital electronic database. Cases with three consecutive weekly performed negative RSC were considered to be decolonized. RSC were processed according to CDC protocol; briefly, the swab was inoculated into 10 mL of trypticase soy broth (bioMérieux Inc., Marcy-l’Étoile, France) with the addition of one 10-μg ertapenem disk (Oxoid, Altrincham, UK) and incubated at 35°C for 18–20 h. The next day, after vortexing, 100 μL of the inoculum was subcultured (8) onto chromID CARBA agar plates (bioMérieux) and incubated at 35°C for 18–20 h. Suspected CRE colonies on chromID CARBA (blue/green to blue/gray in color) were identified by the VITEK MS system (bioMérieux). Susceptibility testing of the isolates was performed with the VITEK 2 system (bioMérieux). Isolates were tested for their resistance phenotypes to imipenem, ertapenem, and meropenem by E-test (bioMérieux). The results were interpreted according to the EUCAST criteria. Results Fifteen cases [2 women, mean age 60.6 ± 18.3 (min. 18–max. 83)] fulfilled the inclusion criteria. All had a history of carbapenem usage. Five cases (33%) had three consequent negative RSC after SBST and were considered to be decolonized. Twelve cases were receiving concomitant antibiotic during SBST (10 carbapenem based regimens). Three cases who received no concomitant antibiotic were decolonized. Conclusion SBST may be a promising tool for decolonizing CRE carriers. These data need to be validated in larger cohorts preferably via randomized-controlled trials. Disclosures All authors: No reported disclosures.

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