Original scientific paper

https://doi.org/10.20471/acc.2022.61.01.06

Investigation of Tigecycline Susceptibility of Multidrug-Resistant Acinetobacter Baumannii Isolates by Disc Diffusion, Agar Gradient and Broth Microdilution Tests

Emel Çalışkan ; Duzce University Faculty of Medicine, Department of Medical Microbiology, Duzce, Turkey
Nevin İnce ; Duzce University Faculty of Medicine, Department of Clinical Microbiology and Infectious Diseases, Duzce, Turkey
Nida Akar ; Hacettepe University Faculty of Medicine, Department of Medical Mycology, Ankara, Turkey
Cihadiye Elif Öztürk ; Duzce University Faculty of Medicine, Department of Medical Microbiology, Duzce, Turkey

Abstract

The use of tigecycline is becoming increasingly important because of the high
levels of antibiotic resistance in Acinetobacter baumannii (A. baumannii) isolates. In this prospective
study, multidrug-resistant A. baumannii isolates were obtained from various tissue and fluid samples
of patients admitted to or treated at various departments and tested in Laboratory of Microbiology,
Duzce University Medical Faculty between January 2013 and December 2015. Tigecycline
resistance in multidrug-resistant A. baumannii isolates were analyzed using the disc diffusion test
(DDT), agar gradient test (AGT), and gold standard test [broth microdilution test (BMT)]. A.
baumannii isolates resistant to multiple drugs were included in the study (N=94). Using the BMT
method, 89 (95%), 4 (4%) and 1 (1%) A. baumannii isolates were determined as tigecycline susceptible,
intermediate and resistant isolates, respectively. Using the Food and Drug Administration
criteria, the rates of major error (ME), minor error (mE) and categorical agreement (CA) for DDT
were 26%, 67% and 9%, respectively. In contrast, for AGT, the rates of ME, mE and CA were 0%,
4%, 95%, respectively. Tigecycline resistance as assessed by BMT showed no increase between 2013
and 2015. Accordingly, isolates found to be resistant or intermediate by DDT should be confirmed
by BMT. Due to the ease of application, AGT is a safe method of detecting susceptibility.

Keywords

Acinetobacter baumannii; Agar gradient test; Broth microdilution test; Disc diffusion test; Multidrug-resistance; Tigecycline

Hrčak ID:

280116

URI

https://hrcak.srce.hr/280116

Publication date:

1.3.2022.

Article data in other languages: croatian

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