Performance of ceftazidime/avibactam susceptibility testing methods against clinically relevant Gram-negative organisms.
J Antimicrob Chemother
; 74(3): 633-638, 2019 03 01.
Article
em En
| MEDLINE
| ID: mdl-30534964
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.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Testes de Sensibilidade Microbiana
/
Ceftazidima
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Compostos Azabicíclicos
/
Inibidores de beta-Lactamases
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Bactérias Gram-Negativas
/
Antibacterianos
Tipo de estudo:
Evaluation_studies
/
Guideline
Limite:
Humans
Idioma:
En
Revista:
J Antimicrob Chemother
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Estados Unidos