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Assessment of rapid direct E-test on positive blood culture for same-day antimicrobial susceptibility.

Abstract

INTRODUCTION

Early and appropriated antimicrobial therapy showed to positively impact on the clinical improvement of septic patients. The aim of this study was to evaluate E-test methodology to obtain rapid results of antimicrobial susceptibility, starting directly from blood culture bottles positive to Gram-negative monomicrobial flora.

MATERIALS AND METHODS

One hundred and five blood culture samples positive to Gram-negative rods at the microscopic examination were collected. Bacterial identification from early subculture on blood agar after 4 h incubation and rapid direct E-test from blood culture broth were performed on every sample. Antibiotics MIC were achieved after 5-6 h of incubation. Resulting MIC values were compared with those obtained with reference E-test from the overnight subculture. Categorical agreement (CA) and essential agreement (EA) were evaluated.

RESULTS

Comparison between rapid direct E-test and reference E-test showed CA ranging from 95.1 to 100 % and 88.2 to 100 % for Enterobacteriaceae (EB) and for non-fermenting Gram-negative bacilli, respectively. Rapid direct E-test showed an overall EA of 80.1 %, revealing different EA rates for the tested antibiotics. Among carbapenemase-producing EB, CA of 87.5 % and EA of 75.5 % for MP were achieved.

DISCUSSION

The same-day communication of the antimicrobial susceptibility represents an important challenge in the multidrug-resistance era. Despite not being able to anticipate actual MIC values, the rapid direct E-test may be useful to obtain preliminary AST results in 5-6 h, especially if used in association with phenotypic or genotypic tests to identify the main resistance mechanisms.

Authors+Show Affiliations

Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88, 10126, Turin, Italy.Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88, 10126, Turin, Italy. marco.iannaccone@unito.it.Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88, 10126, Turin, Italy.Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88, 10126, Turin, Italy.Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, Corso Bramante 88, 10126, Turin, Italy.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31432464

Citation

Bianco, Gabriele, et al. "Assessment of Rapid Direct E-test On Positive Blood Culture for Same-day Antimicrobial Susceptibility." Brazilian Journal of Microbiology : [publication of the Brazilian Society for Microbiology], 2019.
Bianco G, Iannaccone M, Boattini M, et al. Assessment of rapid direct E-test on positive blood culture for same-day antimicrobial susceptibility. Braz J Microbiol. 2019.
Bianco, G., Iannaccone, M., Boattini, M., Cavallo, R., & Costa, C. (2019). Assessment of rapid direct E-test on positive blood culture for same-day antimicrobial susceptibility. Brazilian Journal of Microbiology : [publication of the Brazilian Society for Microbiology], doi:10.1007/s42770-019-00139-6.
Bianco G, et al. Assessment of Rapid Direct E-test On Positive Blood Culture for Same-day Antimicrobial Susceptibility. Braz J Microbiol. 2019 Aug 20; PubMed PMID: 31432464.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Assessment of rapid direct E-test on positive blood culture for same-day antimicrobial susceptibility. AU - Bianco,Gabriele, AU - Iannaccone,Marco, AU - Boattini,Matteo, AU - Cavallo,Rossana, AU - Costa,Cristina, Y1 - 2019/08/20/ PY - 2019/02/19/received PY - 2019/08/08/accepted PY - 2019/8/22/entrez KW - Antimicrobial susceptibility KW - Blood culture KW - E-test KW - Gram-negative bacilli JF - Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology] JO - Braz. J. Microbiol. N2 - INTRODUCTION: Early and appropriated antimicrobial therapy showed to positively impact on the clinical improvement of septic patients. The aim of this study was to evaluate E-test methodology to obtain rapid results of antimicrobial susceptibility, starting directly from blood culture bottles positive to Gram-negative monomicrobial flora. MATERIALS AND METHODS: One hundred and five blood culture samples positive to Gram-negative rods at the microscopic examination were collected. Bacterial identification from early subculture on blood agar after 4 h incubation and rapid direct E-test from blood culture broth were performed on every sample. Antibiotics MIC were achieved after 5-6 h of incubation. Resulting MIC values were compared with those obtained with reference E-test from the overnight subculture. Categorical agreement (CA) and essential agreement (EA) were evaluated. RESULTS: Comparison between rapid direct E-test and reference E-test showed CA ranging from 95.1 to 100 % and 88.2 to 100 % for Enterobacteriaceae (EB) and for non-fermenting Gram-negative bacilli, respectively. Rapid direct E-test showed an overall EA of 80.1 %, revealing different EA rates for the tested antibiotics. Among carbapenemase-producing EB, CA of 87.5 % and EA of 75.5 % for MP were achieved. DISCUSSION: The same-day communication of the antimicrobial susceptibility represents an important challenge in the multidrug-resistance era. Despite not being able to anticipate actual MIC values, the rapid direct E-test may be useful to obtain preliminary AST results in 5-6 h, especially if used in association with phenotypic or genotypic tests to identify the main resistance mechanisms. SN - 1678-4405 UR - https://www.unboundmedicine.com/medline/citation/31432464/Assessment_of_rapid_direct_E-test_on_positive_blood_culture_for_same-day_antimicrobial_susceptibility L2 - https://dx.doi.org/10.1007/s42770-019-00139-6 DB - PRIME DP - Unbound Medicine ER -