Tuberculosis and Respiratory Diseases

The Korean Academy of Tuberculosis and Respiratory Diseases (대한결핵및호흡기학회)
권호 표지

Comparison of Smear and Culture Positivity using NaOH Method and NALC-NaOH Method for Sputum Treatment

객담 전처리 방법에 따른 객담 항산균 도말 및 배양 양성률 비교연구

  • Received : 2008.10.16
  • Accepted : 2008.11.17
  • Published : 2008.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

Background: Sputum decontamination with NALC-NaOH (N-acetyl-L-cysteine-sodium hydroxide) is known to better detect Mycobacterium tuberculosis (M. tb) by culture than that with using NaOH, which is widely used in Korean hospitals. In this report, sputum samples collected from pulmonary tuberculosis (TB) patients were treated with either NaOH or NALC-NaOH, and we compared the results of smear and culture positivity to determine whether the NALC-NaOH treatment method improves culture positivity in the sputum samples, and especially for those sputum samples that are smear negative and scanty. Methods: For each decontamination method, 436 sputum samples from pulmonary TB patients in the National Masan Tuberculosis Hospital were collected for this study. Sputum from a patient was collected two times for the first and second day of sampling time, and these samples were employed for the decontamination process by performing the 4% NaOH and NALC-2% NaOH treatment methods, respectively, for detecting M. tb by an AFB (Acid Fast Bacilli) smear and also by culture in solid Ogawa medium. Results: The NaOH and NALC-NaOH treatment methods did not significantly affect the AFB smear positivity of the sputum samples (33.0% vs 39.0%, respectively, p=0.078). However, the culture positive percents of M. tb in the Ogawa medium treated with NALC-NaOH and NaOH were 39.7% and 28.0%, respectively, which was a significantly different (p=0.0003). This difference in culture was more prominent in the sputum samples that were smear negative (the positive percents with NALC-NaOH and NaOH were 15.8% and 7.2%, respectively, p=0.0017) and scanty (NALC-NaOH and NaOH were 60.8% and 42.9%, respectively, p=0.036), but not for a smear that was 1+ or higher (p>0.05). Conclusion: NALC-NaOH treatment is better than NaOH treatment for the detection of M. tb by culture, but not by smear, and especially when the AFB smear is negative and scanty.

연구배경: NaOH (sodium hydroxide) 기법을 이용한 전처리 객담과 NALC-NaOH (N-acetyl-L-cysteine-sodiumhydroxide) 기법을 이용한 객담의 항산균 도말 및 결핵균배양 양성률 그리고 배지 오염률을 비교하여 실험실 검사과정 중의 일부분을 개선함으로써 검사 결과의 개선이 가능한 지 확인하고자 하였다. 방 법: 2007년 6월부터 2008년 6월까지 국립마산병원에서 객담 검사가 시행된 환자를 대상으로 환자에게서 객담배출 요령을 충분히 교육한 후 두개의 객담 검체를 채취하여 통상적인 NaOH 기법과 NALC-NaOH 기법을 각각 적용한 후 도말 및 배양 결과 그리고 배지 오염률을 비교하였다(n=436). 결 과: 항산균 도말 검사에서는 NaOH 기법에 비하여 NALC-NaOH 기법이 다소 높은 양성률(33.0% vs. 39.0%)을 보였으나 통계적인 유의성은 없었다(p=0.078). 결핵균배양 검사에서는 배지 오염률(culture contamination)은 각각 3.2%와 3.0%로 유의한 차이는 보이지 않았다. 배양양성률은 NALC-NaOH 기법이 통계적으로 유의하게 높은 배양 양성률(39.7% vs. 28.0%, p=0.0003)을 보였으며, 배양 결과를 도말 검사 결과와 연관 지어 분석하였을 때 도말 검사상 음성인 경우 NaOH 기법과 NALC-NaOH 기법은 각각 7.2%와 15.8% (p=0.0017), scanty를 보인 객담의 경우 각각 42.9%와 60.8% (p=0.036)의 배양 양성률을 보여 통계적으로 의미 있는 차이를 보였다. 결 론: 도말 검사에서 음성이나 scanty를 보여 상대적으로 결핵균의 수가 적은 객담의 경우 NALC-NaOH를 이용함으로써 배양 양성률을 개선 시킬 수 있었으며 이는 임상적으로 폐결핵의 진단과 치료 경과 관찰에 직접적인 도움을 줄 수 있음을 보여주었다.

Keywords

References

  1. Kent PT, Kubica GP. Public health mycobacteriology: guide for the Level III Laboratory. 2nd ed. Atlanta: US Department of Health and Human Services, Centers for Disease Control; 1985.
  2. Chang CL, Park TS, Kim MN, Lee NY, Lee HJ, Suh JT. Survey on changes in mycobacterial testing practices in Korean laboratories. Korean J Clin Microbiol 2001;4:108-14.
  3. World Health Organization. Laboratory services in tuberculosis control. Part II. Microscopy. Geneva: World Health Organization; 1998.
  4. World Health Organization. Laboratory services in tuberculosis control. Part III. Culture. Geneva: World Health Organization; 1998.
  5. Scott CP, Dos Anjos Filho L, De Queiroz Mello FC, Thornton CG, Bishai WR, Fonseca LS, et al. Comparison of C(18)-carboxypropylbetaine and standard N-acetyl-L-cysteine-NaOH processing of respiratory specimens for increasing tuberculosis smear sensitivity in Brazil. J Clin Microbiol 2002;40:3219-22. https://doi.org/10.1128/JCM.40.9.3219-3222.2002
  6. Yegian D, Budd V. Toxic effect of sodium hydroxide on tubercle bacilli. Am J Clin Pathol 1952;22:456-60. https://doi.org/10.1093/ajcp/22.5.456
  7. Ratnam S, March SB. Effect of relative centrifugal force and centrifugation time on sedimentation of mycobacteria in clinical specimens. J Clin Microbiol 1986;23:582-5.
  8. Smithwick RW, Stratigos CB, David HL. Use of cetylpyridinium chloride and sodium chloride for the decontamination of sputum specimens that are transported to the laboratory for the isolation of Mycobacterium tuberculosis. J Clin Microbiol 1975;1:411-3.
  9. Tacquet A, Tison F, Devulder B, Roos P. Techniques for decontamination of pathological specimens for culturing mycobacteria. Bull Int Union Tuberc 1967;39:21-4.
  10. Beam RE, Kim KS, Kubica GP. Comparison of different digestion-decontamination methods for recovery of mycobacteria from sputum: a suggested method for "field processing" of sputa. Scand J Respir Dis 1967;48:136-41.
  11. Sula L. Comparative trials with different decontaminating agents for growing Mycobacterium tuberculosis from sputum specimens. Bull World Health Organ 1968;39:647-55.
  12. Jeong J, Chang CL. Evaluation of mycobacterial recovery by specimen preparation and inoculating media. Korean J Clin Pathol 2000;20:188-93.
  13. Ganoza CA, Ricaldi JN, Chauca J, Rojas G, Munayco C, Agapito J, et al. Novel hypertonic saline-sodium hydroxide (HS-SH) method for decontamination and concentration of sputum samples for Mycobacterium tuberculosis microscopy and culture. J Med Microbiol 2008;57:1094-8. https://doi.org/10.1099/jmm.0.2008/001339-0
  14. Chakravorty S, Dudeja M, Hanif M, Tyagi JS. Utility of universal sample processing methodology, combining smear microscopy, culture, and PCR, for diagnosis of pulmonary tuberculosis. J Clin Microbiol 2005;43:2703-8. https://doi.org/10.1128/JCM.43.6.2703-2708.2005
  15. Thornton CG, MacLellan KM, Brink TL Jr, Lockwood DE, Romagnoli M, Turner J, et al. Novel method for processing respiratory specimens for detection of mycobacteria by using C18-carboxypropylbetaine: blinded study. J Clin Microbiol 1998;36:1996-2003.
  16. Thornton CG, MacLellan KM, Brink TL Jr, Wolfe DM, Llorin OJ, Passen S. Processing respiratory specimens with C18-carboxypropylbetaine: development of a sediment resuspension buffer that contains lytic enzymes to reduce the contamination rate and lecithin to alleviate toxicity. J Clin Microbiol 1998;36:2004-13.