Comparison of automated systems using liquid microdilution for the determination of colistin resistance in Klebsiella pneumoniae strains Klebsiella pneumoniae suşlarında kolistin direncinin saptanmasında otomatize sistemlerin sıvı mikrodilüsyon ile karşılaştırılması

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Ezer B., Taşkin Z., Kaba K., Uğrakli S., Doğan M.

Turk Hijyen ve Deneysel Biyoloji Dergisi, cilt.82, sa.1, ss.13-20, 2025 (Scopus, TRDizin)

Özet

Objective: In the detection of colistin resistance in Klebsiella pneumoniae strains with multidrug resistance, automated systems give more erroneous results than the gold standard method, the liquid microdilution method. Comparative studies on the correct detection of colistin resistance by automated systems are limited in the literature. In this study; it is aimed to compare Vitek2 Compact and Phoenix automated systems by using liquid microdilution method in the determination of colistin susceptibility in K. pneumoniae strains isolated from various clinical specimens over a three-year period. Methods: Identification of K. pneumoniae strains was performed using conventional microbiological methods and automated bacterial identification systems which are Vitek2 (bioMérieux, MarcyL’Etoile, France) and Phoenix (Becton dickinson, M50, USA). Antibiotic susceptibility tests were also performed with the same devices. Colistin sensitivity was determined simultaneously with both automated methods and liquid microdilution method. Results: In our study, for the Vitek2 automated system, the Categorical Agreement (CA) ratio is 93.71%, the Very Major Error (VME) rate is 6.89%, and the Minor Error (ME) rate is 1.41%. For the Phoenix automated system, the CA ratio is 95.05%, the VME rate is 3.44%, and the ME rate is 1.51%.Vitek2; specificity is 86.10%, lambda value is 0.82, and kappa value is 0.83. For the Phoenix system, specificity is 88.20%, lambda value is 0.82, and kappa value is 0.87. Conclusion: In determining colistin susceptibility for K. pneumoniae, the Phoenix automated system was found to be more compatible with the reference method than the Vitek2 automated system, and more supportive multicenter studies are needed on this subject.