Evaluation of novel rapid colorimetric colistin resistance detection methods: Rapid Colistin Disc Elution Test in Klebsiella pneumoniae and Rapid Resazurin Disc Elution Test in Acinetobacter baumannii strains

ERDEM F., Durmaz G., YILMAZ M.

Diagnostic microbiology and infectious disease, cilt.115, sa.1, ss.117315, 2026 (SCI-Expanded, Scopus) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 115 Sayı: 1
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.diagmicrobio.2026.117315
  • Dergi Adı: Diagnostic microbiology and infectious disease
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, EMBASE, Environment Index, MEDLINE
  • Sayfa Sayıları: ss.117315
  • Anahtar Kelimeler: Acinetobacter spp., Broth microdilution, CBDE, Colistin resistance, Klebsiella spp, Multidrug-resistant bacteria, Rapid colistin disc elution test, Rapid diagnostic tests, Rapid polymyxin NP test, Rapid resapolymyxin NP test, Rapid resazurin disc elution test
  • Eskişehir Osmangazi Üniversitesi Adresli: Evet

Özet

BACKGROUND: Colistin is a last-resort treatment option for infections caused by multidrug-resistant Gram-negative bacteria. Rapid resistance-detection methods could be viable alternatives to the reference broth microdilution (BMD) method. METHOD: This study was conducted using sixty-four (64) Klebsiella pneumoniae and thirty-four [34] Acinetobacter baumannii strains isolated from hospitalized patients. For Klebsiella pneumoniae strains, BD Phoenix GN AST (Gram-Negative Antimicrobial Susceptibility Testing), CBDE (Colistin Broth Disc Elution Test), novel Rapid Colistin Disc Elution Test (RCDE), and the Rapid Polymyxin NP (RPNP) test, and for Acinetobacter baumannii strains, the Rapid ResaPolymyxin NP (RRNP) test, novel Rapid Resazurin Disc Elution (RRDE) Test, BD Phoenix, and CBDE were evaluated against the reference BMD reference method. RESULTS: In Klebsiella pneumoniae strains, RCDE Test and RPNP tests demonstrated 100% and 98,43% CA(Categorical agreement) rates, while the Phoenix system demonstrated 98.44% CA and 3.03% VME. The CBDE method achieved a ratio of 95.31% CA, 0% VME, and 9.68% ME. In Acinetobacter baumanii strains, the Rapid ResaPolymyxin NP test was the most reliable method, with 100% CA. The Rapid Resazurin Disc Elution (RRDE) Test resulted in some false reports of resistance, with a CA rate of 91.18% and the Phoenix system demonstrated an ME rate of 15.00%, 76.47% CA, 7.1% VME, and 35% ME. The CBDE method demonstrated compatibility with 94.12% CA but exhibited VME at 14.29%. CONCLUSION: The RCDE test is among the tests that can be preferred for its accuracy and practicality in the rapid detection of colistin resistance in Klebsiella pneumoniae strains. RRNP test is the most reliable method for Acinetobacter baumanii strains. However, the RRDE test is also rapid and promising good practical alternative. IMPACT STATEMENT: This study provides a comparative evaluation of different methods for detecting colistin resistance in multidrug-resistant Klebsiella pneumoniae and Acinetobacter baumannii strains. Reliable detection of colistin resistance is essential for guiding appropriate antimicrobial therapy and preventing treatment failures. In particular, our findings emphasize the potential of RCDE test for K. pneumoniae and RRDE test for A. baumannii as a rapid, practical and reliable tool for routine use in clinical microbiology laboratories.