Banca de DEFESA: DANIELA DA SILVA NASCIMENTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DANIELA DA SILVA NASCIMENTO
DATE: 02/03/2023
TIME: 08:30
LOCAL: Virtual
TITLE:

ASSOCIATION OF CEFTAZIDIME/AVIBACTAM AND AZTREONAM AGAINST METAL-β-LACTAMASE PRODUCING BACTERIA: EVALUATION OF THREE IN VITRO SYNERGY METHODS

KEY WORDS:

metallo-β-lactamases; Synergy testes; Ceftazidime/avibactam; Aztreonam; NDM

PAGES: 68
BIG AREA: Ciências da Saúde
AREA: Farmácia
SUBÁREA: Análise Toxicológica
SUMMARY:

Resistance in Gram-negative bacteria is a global health concern due to the lack of viable therapeutic alternatives. Ceftazidime-avibactam (CAZ/AVI) is a combination of a third-generation cephalosporin and a β-lactamase inhibitor that has in vitro activity against serine-type enzymes such as extended spectrum β-lactamase (ESBL) and Klebsiella pneumoniae carbapenemase (KPC) class A, as well as class C cephalosporinases and class D OXA-48, but is ineffective against class B metallo-β-lactamases (MβL) producers. Aztreonam (ATM) is a monobactam that stands against MβL but is inactivated by ESBL, KPC and other cephalosporinases often found in stable preparations produced from MβL. The combined therapy of CAZ/AVI and ATM has been shown to be useful against these microorganisms. However, standardized commercial susceptibility tests for this combination are not available. Thus, testing in the laboratory the synergistic potential of the combination in vitro can guide the choice of an appropriate therapy. This study aims to compare the performance of three methods as predictors of synergistic activity between CAZ/AVI and ATM, in order to find a method that is low cost and easy to perform in a clinical microbiology laboratory. For this, a total of 36 MβL-producing bacteria were evaluated and the synergy test was performed with 30 isolates that showed CAZ/AVI and ATM resistance. Seven isolates were selected for the time-kill assay (TKA). β-lactam resistance genes were detected using the conventional PCR technique. The search for NDM variants was performed using Sanger sequencing. To determine the synergy between the drugs, disk-approximation (DA), overlapping diffusion gradient strips and TKA methods were used, the gold standard for synergy tests. The minimum inhibitory concentration (MIC) was performed by broth microdilution (MIC). Agreement (Kappa index) was calculated as a ratio of concordant responses between the evaluated methods and the TKA. The thirty-six samples tested carried bla_NDM, and 8 (22%) had two metallo β-lactamases (bla_NDM and bla_VIM). Thirty-four isolates (94.4%) were detected as coproducers of metallo and serine β-lactamase, with 10 (27.7%) coproducers of bla_KPC. The NDM-1 variant was detected in 31 (86.1%) samples. Thirty-five samples (97.2%) were considered multidrug resistant. The DA and diffusion gradient tape overlay methodologies agree very well (100%, κ = 1.0, p<0.05). Compared to TKA, the tested methodologies demonstrated sensitivity, specificity, positive predictive value, and negative predictive value of 100%. Twenty-nine (96.7%) showed a synergistic result of the ATM plus CAZ/AVI association so that the addition of avibactam was able to restore sensitivity to aztreonam, meeting MICs greater than 256 ug/mL for MICs less than 1 ug/mL. Thus, with this work it was possible to standardize two possible methodologies to be used in the daily routine of the clinical microbiology laboratory to predict in vitro the synergy of the association of ATM plus CAZ/AVI in isolates of K. pneumoniae producing metallo-β-lactamase

COMMITTEE MEMBERS:
Interna - 2466232 - CYNARA GOMES BARBOSA
Presidente - 1187203 - JOICE NEVES REIS PEDREIRA
Externo à Instituição - MARCELO PILONETTO - PUCPR