Volume 10,Issue 1
Fall 2025
Evaluation of the Use of Distilled Water as a Sodium Hydroxide Wash in Antimicrobial Cultures
Background: Respiratory specimens subjected to mycobacterial detection were initially pretreated with N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) to remove the mucus and normal flora. Next, they were washed and neutralized with a phosphate-buffered solution (PBS). The effectiveness of distilled water (DW) compared to PBS as a washing neutralizer during the identification of mycobacteria was evaluated in this study. Methods: We analyzed the results of the mycobacterial test conducted at a general hospital in Gwangju from October 2016 to September 2018. PBS and DW were used as a respiratory sample-washing agent for one year each. Results: The positive culture rate for the culture of mycobacteria was 12.7% (1,843/14,532) and 14.7% (2,095/14,291), when PBS and DW were used, respectively. The recovery rate of the mycobacteria growth indicator tubes (MGIT) and the separation rates of the Mycobacterium tuberculosis complex and nontuberculous mycobacteria (NTM) showed no significant change. However, in the 2% Ogawa medium, as the NTM culture increased from 47.4% (399/841) to 56.1% (630/1,122), the recovery rate increased from 45.6% (841/1,843) to 53.6% (1,122/2,095). The MGIT contamination rate decreased from 6.5% to 4.1%. Conclusion: DW as a washing agent for NALC-NaOH increased the recovery rate of Ogawa medium and reduced the contamination rate of MGIT. Therefore, the use of DW instead of PBS as a washing neutralizer during the identification of mycobacteria might be useful.
1. Hwang SS, Oh KJ, Jang IH, et al. Evaluation of the Diagnostic Performance of the AdvanSure TB/NTM Real-Time PCR Kit for Detection of Mycobacteria. Korean J Clin Microbiol. 2011;14:55–59.
2. Kim YS, Jo YH, Lee HJ, et al. Comparison of the MGIT (Mycobacteria Growth Indicator Tube) with Ogawa Media for Recovery of Mycobacteria. Korean J Clin Microbiol. 2001;4:58–61.
3. Go UY, Park MS, Kim UN, et al. Tuberculosis Prevention and Care in Korea: Evolution of Policy and Practice. J Clin Tuberc Other Mycobact Dis. 2018;11:28–36.
4. Schlossberg D. Tuberculosis and nontuberculous mycobacterial infections. 6th ed. ASM Press, Washington, DC. 2011.
5. Griffith DE, Aksamit T, Brown-Elliott BA, et al. An Official ATS/IDSA Statement: Diagnosis, Treatment, and Prevention of Nontuberculous Mycobacterial Diseases. Am J Respir Crit Care Med. 2007;175:367–416.
6. Kang H, Sung N, Lee S, et al. Comparison of Smear and Culture Positivity Using NaOH Method and NALC-NaOH Method for Sputum Treatment. Tuberc Respir Dis. 2008;65:379–384.
7. Beran V, Havelkova M, Kaustova J, et al. Cell Wall Deficient Forms of Mycobacteria: A Review. Vet Med. 2006;7:365–389.
8. Yi JY, Kim JP, Shin JH, et al. Detection of Mycobacterium tuberculosis using BACTEC Mycobacteria Growth Indicator Tube (MGIT) 960 System: Comparison with BACTEC 460 TB System and Ogawa Media. Korean J Clin Pathol. 2000;20:384–391.
9. Subramanyam B, Sivaramakrishnan G, Sangamithrai D, et al. Reprocessing of Contaminated MGIT 960 Cultures to Improve Availability of Valid Results for Mycobacteria. Int J Microbiol. 2020;1721020:1–3.
10. Jung H, Bang HI, Choi TY. Evaluation of the Effectiveness of a Re-Decontaminating Process with Bacterial Contaminated Specimens Showing a Positive MGIT Signal for the Detection of Mycobacteria. Korean J Clin Lab Sci. 2019;51:171–176.
11. Krasnow I, Wayne LG. Sputum Digestion. I. The Mortality Rate of Tubercle Bacilli in Various Digestion Systems. Am J Clin Pathol. 1966;45:352–355.
12. Bae E, Im JH, Kim SW, et al. Evaluation of Combination of BACTEC Mycobacteria Growth Indicator Tube 960 System and Ogawa Media for Mycobacterial Culture. Korean J Lab Med. 2008;28:299–306.
13. Joung US, Jeong J, Lee SH, et al. Comparison of Mycobacterial Culture by Mycobacterium Growth Indicator Tube and Ogawa Media. Korean J Clin Microbiol. 2004;7:135–138.
14. Kim YS, Jo YH, Lee HJ, et al. Comparison of the MGIT (Mycobacteria Growth Indicator Tube) with Ogawa Media for Recovery of Mycobacteria. Korean J Clin Microbiol. 2001;4:58–61.