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Increasing trend of isolation of non-tuberculous mycobacteria in a tertiary university hospital in South Korea.

Yoo JW, Jo KW, Kim MN, Lee SD, Kim WS, Kim DS, Shim TS - Tuberc Respir Dis (Seoul) (2012)

Bottom Line: Mycobacterial smear/culture results of respiratory specimens (sputum and bronchial aspirates), obtained during the years 2002, 2005, and 2010, were retrieved and analyzed retrospectively.The annual rate of NTM among positive culture specimens increased from 21% in 2002 to 57.8% in 2010 (p<0.001), as did the proportion of NTM, among AFB smear- and culture-positive specimens, from 12.2% in 2002 to 45.2% in 2010 (p<0.001).The NTM rate among AFB-positive specimens was higher in patients aged >50 than ≤50 years.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT

Background: The isolation of non-tuberculous mycobacteria (NTM) has been increasing in South Korea. To date, however, the cause of this increase has not been determined, and it remains unclear whether the use of liquid media has contributed to this increase. The aim of this study was to evaluate the factors associated with NTM isolation and the impact of liquid media on NTM culture.

Methods: Mycobacterial smear/culture results of respiratory specimens (sputum and bronchial aspirates), obtained during the years 2002, 2005, and 2010, were retrieved and analyzed retrospectively.

Results: During the years 2002, 2005, and 2010, 83,096 sputum specimens were collected from 31,104 patients, and were cultured for mycobacteria, using solid media only in the 2002 and 2005 specimens and both solid and liquid media in the 2010. Of these, 3,516 (4.2%) specimens were smear-positive for acid-fast bacilli (AFB). The annual rate of NTM among positive culture specimens increased from 21% in 2002 to 57.8% in 2010 (p<0.001), as did the proportion of NTM, among AFB smear- and culture-positive specimens, from 12.2% in 2002 to 45.2% in 2010 (p<0.001). In 2010, the NTM culture rate was higher in the liquid than in the solid media (13.9% vs. 8.4%, p<0.001). The NTM rate among AFB-positive specimens was higher in patients aged >50 than ≤50 years.

Conclusion: The rate of NTM isolation has steadily been increasing at the hospital in South Korea, likely due in part to the use of liquid media for the culture.

No MeSH data available.


Related in: MedlinePlus

Recovery rate of Mycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) on solid media in 2002, 2005, and 2010 (p<0.001). (A) Specimens. (B) Patients.
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Figure 1: Recovery rate of Mycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) on solid media in 2002, 2005, and 2010 (p<0.001). (A) Specimens. (B) Patients.

Mentions: During the 3 years of this study, 83,096 sputum specimens were collected from 31,104 patients and cultured for mycobacteria, with 3,516 (4.2%) specimens being smear-positive for AFB (Table 1). M. tuberculosis or NTM was observed in 7,122 (8.6%) sputum specimens cultured in solid media. The mean patient age was 56.7±15.6 years and 60.1% were male. The mean age in 2010 was significantly higher than other years (p <0.001) and was not different between 2002 and 2010 (p=0.992). The male proportion in 2010 was significantly lower compared to that of 2002 or 2005 (p <0.01) and was not different between 2002 and 2005 (p=0.320). The recovery rate of NTM from specimens and proportion of patients with NTM isolation increased from 21% in 2002 to 57.8% in 2010 and from 30.2% in 2002 to 62.9% in 2010, respectively (each p<0.001) (Table 1, Figure 1). The proportion of AFB smear-positive and culture-positive specimens positive for NTM also increased, from 12.2% in 2002 to 45.2% in 2010 (p<0.001) (Table 1). In contrast, the rate of M. tuberculosis isolation declined over time.


Increasing trend of isolation of non-tuberculous mycobacteria in a tertiary university hospital in South Korea.

Yoo JW, Jo KW, Kim MN, Lee SD, Kim WS, Kim DS, Shim TS - Tuberc Respir Dis (Seoul) (2012)

Recovery rate of Mycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) on solid media in 2002, 2005, and 2010 (p<0.001). (A) Specimens. (B) Patients.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3475469&req=5

Figure 1: Recovery rate of Mycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) on solid media in 2002, 2005, and 2010 (p<0.001). (A) Specimens. (B) Patients.
Mentions: During the 3 years of this study, 83,096 sputum specimens were collected from 31,104 patients and cultured for mycobacteria, with 3,516 (4.2%) specimens being smear-positive for AFB (Table 1). M. tuberculosis or NTM was observed in 7,122 (8.6%) sputum specimens cultured in solid media. The mean patient age was 56.7±15.6 years and 60.1% were male. The mean age in 2010 was significantly higher than other years (p <0.001) and was not different between 2002 and 2010 (p=0.992). The male proportion in 2010 was significantly lower compared to that of 2002 or 2005 (p <0.01) and was not different between 2002 and 2005 (p=0.320). The recovery rate of NTM from specimens and proportion of patients with NTM isolation increased from 21% in 2002 to 57.8% in 2010 and from 30.2% in 2002 to 62.9% in 2010, respectively (each p<0.001) (Table 1, Figure 1). The proportion of AFB smear-positive and culture-positive specimens positive for NTM also increased, from 12.2% in 2002 to 45.2% in 2010 (p<0.001) (Table 1). In contrast, the rate of M. tuberculosis isolation declined over time.

Bottom Line: Mycobacterial smear/culture results of respiratory specimens (sputum and bronchial aspirates), obtained during the years 2002, 2005, and 2010, were retrieved and analyzed retrospectively.The annual rate of NTM among positive culture specimens increased from 21% in 2002 to 57.8% in 2010 (p<0.001), as did the proportion of NTM, among AFB smear- and culture-positive specimens, from 12.2% in 2002 to 45.2% in 2010 (p<0.001).The NTM rate among AFB-positive specimens was higher in patients aged >50 than ≤50 years.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT

Background: The isolation of non-tuberculous mycobacteria (NTM) has been increasing in South Korea. To date, however, the cause of this increase has not been determined, and it remains unclear whether the use of liquid media has contributed to this increase. The aim of this study was to evaluate the factors associated with NTM isolation and the impact of liquid media on NTM culture.

Methods: Mycobacterial smear/culture results of respiratory specimens (sputum and bronchial aspirates), obtained during the years 2002, 2005, and 2010, were retrieved and analyzed retrospectively.

Results: During the years 2002, 2005, and 2010, 83,096 sputum specimens were collected from 31,104 patients, and were cultured for mycobacteria, using solid media only in the 2002 and 2005 specimens and both solid and liquid media in the 2010. Of these, 3,516 (4.2%) specimens were smear-positive for acid-fast bacilli (AFB). The annual rate of NTM among positive culture specimens increased from 21% in 2002 to 57.8% in 2010 (p<0.001), as did the proportion of NTM, among AFB smear- and culture-positive specimens, from 12.2% in 2002 to 45.2% in 2010 (p<0.001). In 2010, the NTM culture rate was higher in the liquid than in the solid media (13.9% vs. 8.4%, p<0.001). The NTM rate among AFB-positive specimens was higher in patients aged >50 than ≤50 years.

Conclusion: The rate of NTM isolation has steadily been increasing at the hospital in South Korea, likely due in part to the use of liquid media for the culture.

No MeSH data available.


Related in: MedlinePlus