KOLİSTİN DUYARLILIK TESTİ İÇİN DIAGNOSTICS COLISTIN MIC-STRIP TESTİNİN DEĞERLENDİRİLMESİ

Öz

Günümüzde çoklu ilaç direncine sahip Gram negatif mikroorganizmaların neden olduğu enfeksiyonların tedavisinde kullanılacak antimikrobiyallerin kısıtlı olması nedeniyle kolistin gibi eski antibiyotikler sıklıkla tercih edilmeye başlanmıştır. Ancak, kolistinin katyonik yapısı nedeniyle rutin laboratuvarda sıklıkla kullanılan antibiyotik duyarlılık testlerinde (disk difüzyon, gradient test, otomatize sistemler) birtakım sorunlar yaşanmaktadır. Bu nedenle European Committee on Antimicrobial Susceptibility Testing (EUCAST) ve Clinical and Laboratory Standards Institute (CLSI) tarafından kolistin duyarlılığını saptamak için sadece sıvı mikrodilüsyon testi önerilmektedir. Ancak sıvı mikrodilüsyon testlerinin zaman alıcı ve zahmetli olması nedeniyle rutin laboratuvarlarında hızlı ve güvenilir kolistin duyarlılığı sonucu sağlayabilen testlere ihtiyaç duyulmaktadır. Bu çalışmada, Klebsiella pneumoniae ve Acinetobacter baumannii kökenlerinde kolistin duyarlılığının saptanmasında ticari olarak hazır olarak üretilen Diagnostics MIC-COL (Diagnostics I.n.c., Galanta, Slovakya) testinin performansının değerlendirilmesi amaçlanmıştır. Rutin laboratuvarımızda 2016-2019 yılları arasında çeşitli klinik örneklerden izole edilen K.pneumoniae (n=22) ve A.baumannii (n=28) kökenleri çalışmaya dahil edilmiştir. Kökenlerin kolistin minimum inhibitör konsantrasyonları (MİK) hem referans yöntem olan sıvı mikrodilüsyon yöntemi ile hem de ticari olarak üretilen Diagnostics MIC-COL testi ile çalışılmıştır. Elde edilen sonuçlar karşılaştırılarak testin temel uyum, kategorik uyum, büyük hata ve çok büyük hata oranları hesaplanmıştır. Sıvı mikrodilüsyon yöntemi ile karşılaştırıldığında Diagnostics MIC-COL testinin temel uyumu % 84, kategorik uyumu % 98, büyük hata oranı % 3,8 olarak tespit edilirken çok büyük hata tespit edilmemiştir. Rutin laboratuvarlarda hızlı ve güvenilir kolistin duyarlılığının tespit edilerek tedavinin yönlendirilmesi oldukça önemlidir. Çalışmamızda kullanılan ticari test kullanımı kolay ve zaman alıcı olmayan bir testtir. Ayrıca strip şeklinde olması sayesinde her izolat ayrı çalışılabilmektedir. Büyük hata oranının beklenilen değerlerin üzerinde olması nedeniyle daha fazla sayıda ve farklı direnç düzeylerine sahip kökenlerle yapılacak ileri çalışmalarla bu oranların yeniden değerlendirilmesi faydalı olacaktır.

Anahtar Kelimeler

• A.baumannii
• diagnostics MIC-COL-strip
• kolistin duyarlılığı
• K.pneumoniae

Evaluation of Diagnostics Colistin MIC-Strip Test for Colistin Susceptibility Testing

Öz

Due to the limited number of antimicrobials to be used in the treatment of infections caused by Gram-negative microorganisms with multi-drug resistance recently, old antibiotics such as colistin have started to be preferred frequently. However, some problems are encountered in antibiotic susceptibility tests (disk diffusion, gradient test, automated systems) which are frequently used in the routine laboratory due to the cationic nature of colistin. For this reason, only the broth microdilution test is recommended by European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) for the detection of colistin susceptibility. Since broth microdilution tests are time consuming and inconvenient, tests that can provide fast and reliable colistin susceptibility result is needed in routine laboratories. In this study, it was aimed to evaluate the performance of the commercially produced Diagnostics MIC-COL test (Diagnostics I.n.c, Galanta, Slovakia) for the detection of colistin susceptibility in Klebsiella pneumoniae and Acinetobacter baumannii strains. The strains of K.pneumoniae (n = 22) and A.baumannii (n = 28) isolated from various clinical specimens between 2016 and 2019 in our routine laboratory were included in the study. Colistin minimum inhibitory concentrations (MIC) of the strains were studied with both the reference broth microdilution method and the commercially produced Diagnostics Colistin MIC-COL test. The essential agreement, categorical agreement, major error, and very major error rates of the test were calculated by comparing the obtained results. The essential agreement of the Diagnostics Colistin MIC-Strip test was determined as 84 %, categorical agreement as 98 %, and major error rate as 3.8 %, while no very major error was detected. İt is very important to guide antimicrobial treatment with rapid and reliable detection of colistin susceptibility. The commercial test used in our study is easy to use and not time-consuming. Also, due to its strip from, each isolate can be studied separately. Because of the major error rate being above the expected values, it will be useful to re-evaluate these rates with further studies to be conducted with a larger number of strains with different resistance levels.

Anahtar Kelimeler

• A.baumannii
• colistin susceptibility
• diagnostics MIC-COL-strip
• K.pneumoniae

Kaynakça

1. Baron S, Hadjadj L, Rolain JM, Olaitan AO. Molecular mechanisms of polymyxin resistance: knowns and unknowns. Int J Antimicrob Ag. 2016;48(6):583-91. https://doi.org/10.1016/j.ijantimicag.2016.06.023
2. Caniaux I, van Belkum A, Zambardi G, Poirel L, Gros MF. MCR: modern colistin resistance. Eur J Clin Microbiol Infect Dis. 2017;36(3):415-20. https://doi.org/10.1007/s10096-016-2846-y
3. Chew KL, La MV, Lin RTP, Teo JWP. Colistin and polymyxin b susceptibility testing for carbapenemresistant and mcr-positive Enterobacteriaceae:comparison of Sensititre, MicroScan, Vitek 2, and Etest with broth microdilution. Journal of Clinical Microbiology. 2017;55(9):2609-16. https://doi.org/10.1128/JCM.00268-17
4. Dafopoulou K, Zarkotou O, Dimitroulia E, et al. Comparative evaluation of colistin susceptibility testing methods among carbapenem-nonsusceptible Klebsiella pneumoniae and Acinetobacter baumannii clinical isolates. Antimicrob Agents Chemother 2015;59(8):4625-30. https://doi.org/10.1128/AAC.00868-15
5. ECDC. Plasmid-mediated colistin resistance in Enterobacteriace ae. 2016. https://ecdc.europa.eu/ sites/portal/files/media/en/publications/Publications/enterobacteriaceae-risk-assessment-diseases-causedby-antimicrobial-resistant-microorganisms-europejune-2016.pdf.
6. European Committee on Antimicrobial Susceptibility Testing. Recommendations for MIC determination of colistin (polymyxin E) as recommended by the joint CLSI-EUCAST Polymyxin Breakpoints Working Group. (2016).
7. European Committee on Antimicrobial Susceptibility Testing. 2019. Breakpoint tables for interpretation of MICs and zone diameters, version 9.0.(2019).
8. Ezadi F, Ardebili A, Mirnejad R. Antimicrobial susceptibility testing for polymyxins: challenges, issues, and recommendations. J Clin Microbiol. 2019;57(4). https://doi.org/10.1128/JCM.01390-18

9. Galani I, Kontopidou F, Souli M, et al. Colistin susceptibility testing by Etest and disk diffusion methods. Int J Antimicrob Agents. 2008;31(5):434-9. https://doi.org/10.1016/j.ijantimicag.2008.01.011
10. Girardello R, Cury AP, Franco MRG, et al. Colistin susceptibility testing and Vitek-2 (TM): is it really useless? Diagn Microbiol Infect Dis. 2018;91(4):309-11. https://doi.org/10.1016/j.diagmicrobio.2018.03.019
11. International Organization for Standardization (ISO).Clinical Laboratory Testing and In Vitro Diagnostic Test Systems. Susceptibility Testing of Infectious Agents and Evaluation of Performance of Antimicrobial Susceptibility Test Devices. Part 2: Evaluation of Performance of Antimicrobial Susceptibility Test Devices. International Standard ISO 20776-2:2007. Geneva, Switzerland. (2007).
12. Lee SY, Shin JH, Lee K, et al. Comparison of the Vitek 2,MicroScan, and etest methods with the agar dilution method in assessing colistin susceptibility of bloodstream isolates of Acinetobacter species from a Korean University Hospital. J Clin Microbiol. 2013;51(6):1924-6. https://doi.org/10.1128/JCM.00427-13
13. Liu YY, Wang Y, Walsh TR, et al. Emergence of plasmidmediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study. Lancet Infect Dis. 2016;16(2):161-8. https://doi.org/10.1016/S1473-3099(15)00424-7
14. Lo-Ten-Foe JR, de Smet AMGA, Diederen BMW, Kluytmans JAJW, van Keulen PHJ. Comparative evaluation of the VITEK 2, disk diffusion, etest, brothmicrodilution, and agar dilution susceptibility testing methods for colistin in clinical isolates, including heteroresistant Enterobacter cloacae and Acinetobacter baumannii strains. Antimicrob AgentsChemother. 2007;51(10):3726-30. https://doi.org/10.1128/AAC.01406-06
15. Maalej SM, Meziou MR, Rhimi FM, Hammami A. Comparison of disc diffusion, Etest and agar dilution for susceptibility testing of colistin againstEnterobacteriaceae. Lett Appl Microbiol. 2011;53(5):546-51.https://doi.org/10.1111/j.1472-765X.2011.03145.x
16. Matuschek E, Ahman J, Webster C, Kahlmeter G.Antimicrobial susceptibility testing of colistin - evaluation of seven commercial MIC products against standard broth microdilution for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter spp. Clin Microbiol Infec. 2018;24(8):865- 70. https://doi.org/10.1016/j.cmi.2017.11.020
17. Tan TY, Lily SYN. Comparison of three standardized disc susceptibility testing methods for colistin. J Antimicrob Chemother. 2006;58(4):864-7. https://doi.org/10.1093/jac/dkl330
18. Vasoo S. Susceptibility Testing for the polymyxins: two steps back, three steps forward? J Clin Microbiol. 2017;55(9):2573-82. https://doi.org/10.1128/JCM.00888-17
19. Vourli S, Dafopoulou K, Vrioni G, Tsakris A, Pournaras S. Evaluation of two automated systems for colistin susceptibility testing of carbapenem-resistant Acinetobacter baumannii clinical isolates. J Antimicrob Chemother. 2017;72(9):2528-30.