Ann Lab Med.  2015 Jul;35(4):416-422. 10.3343/alm.2015.35.4.416.

Direct Identification of Urinary Tract Pathogens From Urine Samples Using the Vitek MS System Based on Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry

Affiliations
  • 1Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea. yjpk@catholic.ac.kr
  • 2Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea.

Abstract

BACKGROUND
We evaluated the coincidence rate between Vitek MS system (bioMerieux, France) and Vitek 2 in identifying uropathogens directly from urine specimens.
METHODS
Urine specimens submitted to our microbiology laboratory between July and September 2013 for Gram staining and bacterial culture were analyzed. Bacterial identification was performed by using the conventional method. Urine specimens showing a single morphotype by Gram staining were processed by culturing and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Of 2,370 urine specimens, 251 showed a single morphotype on Gram staining, and among them, 202 were available for MALDI-TOF MS.
RESULTS
In these 202 specimens, colony growth was observed in 189 specimens, and 145 specimens had significant growth of single-colony morphotype in culture. One hundred and ten (75.9%) of them had colony counts of > or =10(5) colony-forming units (CFU)/mL and included 71 enteric gram-negative bacteria (GNB), 5 glucose-non-fermenting GNB, 9 gram-positive cocci (GPC), and 25 yeasts. Furthermore, 70 (98.6%), 3 (60.0%), 4 (44.4%), and 5 (20.0%), respectively, of these were correctly identified by Vitek MS. Thirty-one specimens (21.4%; 11 GNB, 7 GPC, 12 yeasts, and 1 gram-positive bacillus) had colony counts of 10(4)-10(5) CFU/mL. Four specimens (2.8%) yielded colony counts of 10(3)-10(4) CFU/mL.
CONCLUSIONS
Vitek MS showed high rate of accuracy for the identification of GNB in urine specimens (> or =10(5) CFU/mL). This could become a rapid and accurate diagnostic method for urinary tract infection caused by GNB. However, for the identification of GPC and yeasts, further studies on appropriate pre-treatment are warranted.

Keyword

Urinary tract pathogens; MALDI-TOF MS; Vitek MS; UTI

MeSH Terms

Gram-Negative Bacteria
Gram-Positive Cocci
Mass Spectrometry*
Stem Cells
Urinary Tract Infections
Urinary Tract*
Yeasts

Cited by  1 articles

Direct Identification and Antimicrobial Susceptibility Testing of Bacteria From Positive Blood Culture Bottles by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry and the Vitek 2 System
Sung Jin Jo, Kang Gyun Park, Kyungja Han, Dong Jin Park, Yeon-Joon Park
Ann Lab Med. 2016;36(2):117-123.    doi: 10.3343/alm.2016.36.2.117.


Reference

1. Trautner BW. Management of catheter-associated urinary tract infection. Curr Opin Infect Dis. 2010; 23:76–82. PMID: 19926986.
Article
2. Isikgoz Tasbakan M, Durusoy R, Pullukcu H, Sipahi OR, Ulusoy S. 2011 Turkish Nosocomial Urinary Tract Infection Study Group. Hospital-acquired urinary tract infection point prevalence in Turkey: differences in risk factors among patient groups. Ann Clin Microbiol Antimicrob. 2013; 12:31. PMID: 24188193.
Article
3. Burd EM. A critical appraisal of the role of the clinical microbiology laboratory in the diagnosis of urinary tract infections. J Clin Microbiol. 2011; 49(S9):S34–S38.
Article
4. Dubois D, Grare M, Prere MF, Segonds C, Marty N, Oswald E. Performances of the Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry system for rapid identification of bacteria in routine clinical microbiology. J Clin Microbiol. 2012; 50:2568–2576. PMID: 22593596.
Article
5. Won EJ, Shin JH, Lee K, Kim MN, Lee HS, Park YJ, et al. Accuracy of species-level identification of yeast isolates from blood cultures from 10 university hospitals in South Korea by use of the matrix-assisted laser desorption ionization-time of flight mass spectrometry-based Vitek MS system. J Clin Microbiol. 2013; 51:3063–3065. PMID: 23784123.
Article
6. Wang XH, Zhang G, Fan YY, Yang X, Sui WJ, Lu XX. Direct identification of bacteria causing urinary tract infections by combining matrix-assisted laser desorption ionization-time of flight mass spectrometry with UF-1000i urine flow cytometry. J Microbiol Methods. 2013; 92:231–235. PMID: 23305925.
Article
7. Ferreira L, Sánchez-Juanes F, González-Avila M, Cembrero-Fuciños D, Herrero-Hernández A, González-Buitrago JM, et al. Direct identification of urinary tract pathogens from urine samples by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol. 2010; 48:2110–2115. PMID: 20392910.
Article
8. Garcia LS, editor. Clinical microbiology procedure handbook. 3rd ed. Washington DC: ASM press;2010. p. 3.2.16.
9. Lavergne RA, Chauvin P, Valentin A, Fillaux J, Roques-Malecaze C, Arnaud S, et al. An extraction method of positive blood cultures for direct identification of Candida species by Vitek MS matrix-assisted laser desorption ionization time of flight mass spectrometry. Med Mycol. 2013; 51:652–656. PMID: 23373445.
10. Moon HW, Lee SH, Chung HS, Lee M, Lee K. Performance of the Vitek MS matrix-assisted laser desorption ionization time-of-flight mass spectrometry system for identification of Gram-positive cocci routinely isolated in clinical microbiology laboratories. J Med Microbiol. 2013; 62:1301–1306. PMID: 23764744.
Article
11. Jamal WY, Ahmad S, Khan ZU, Rotimi VO. Comparative evaluation of two matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems for the identification of clinically significant yeasts. Int J Infect Dis. 2014; 26:167–170. PMID: 25080355.
Article
12. Westblade LF, Jennemann R, Branda JA, Bythrow M, Ferraro MJ, Garner OB, et al. Multicenter study evaluating the Vitek MS system for identification of medically important yeasts. J Clin Microbiol. 2013; 51:2267–2272. PMID: 23658267.
Article
13. Tudela E, Muñoz G, Muñoz-Guerra JA. Matrix effect marker for multianalyte analysis by LC-MS/MS in biological samples. J Chromatogr B Analyt Technol Biomed Life Sci. 2012; 901:98–106.
Article
14. Köhling HL, Bittner A, Müller KD, Buer J, Becker M, Rübben H, et al. Direct identification of bacteria in urine samples by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and relevance of defensins as interfering factors. J Med Microbiol. 2012; 61:339–344. PMID: 22275503.
Article
15. Drancourt M. Detection of microorganisms in blood specimens using matrix-assisted laser desorption ionization time-of-flight mass spectrometry: a review. Clin Microbiol Infect. 2010; 16:1620–1625. PMID: 20545958.
Article
16. Guo L, Ye L, Zhao Q, Ma Y, Yang J, Luo Y. Comparative study of MALDI-TOF MS and VITEK 2 in bacteria identification. J Thorac Dis. 2014; 6:534–538. PMID: 24822115.
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