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Clinical Significance of Mycobacterium avium Complex Isolates at a Medical Center in Northern Taiwan
J Formos Med Assoc 2011;110(8):548–549
Contents lists available at ScienceDirect
Volume 110 Number 8 August 2011
Journal of the Formosan Medical Association
ISSN 0929 6646
Journal of the
Formosan Medical Association Resveratrol for prophylaxis of ischemic stroke Microglia and chronic pain ART in HIV-1-discordant couples in Taiwan Prognostic evaluation of patients with multicentric papillary thyroid microcarcinoma
Journal homepage: http://www.jfma-online.com
Formosan Medical Association Taipei, Taiwan
Letter to the Editor
Clinical Significance of Mycobacterium avium Complex Isolates at a Medical Center in Northern Taiwan Chong-Un Cheong,1 Chih-Cheng Lai,1 Po-Ren Hsueh2*
MAC colonization was noted in 210 (75.3%) patients, and MAC caused NTM disease in 69 (24.7%) patients, based on the 2007 criteria of the American Thoracic Society/Infectious Diseases Society of America.2 Those findings were consistent with those from our previous study conducted during the period January 2000 to December 2008 at the same institution.3 In that study, a total of 9,204 NTM isolates were recovered from 4,786 patients, and 2,761 isolates from 1,515 patients were confirmed to be MAC. Among those patients, MAC colonization was noted in 1,282 (84.6%) and MAC caused NTM diseases in 233 (15.4%). The annual prevalence of MAC colonization ranged from 80.0% (2000) to 87.4% (2006). These findings are consistent with those reported by Shen et al,1 namely that only 12 (22.2%) of 54 patients with positive MAC isolates had clinically significant MAC pulmonary disease. In addition, trend analysis has revealed that the annual incidence (per 100,000 inpatients and outpatients) of MAC colonization increased
We read with great interest the case report by Shen et al1 in the July 2010 issue of Journal of the Formosan Medical Association. In that retrospective study, the authors described the clinical significance of Mycobacterium avium complex (MAC) that had been isolated from respiratory specimens at a medical center in southern Taiwan. We wonder whether similar findings could be noted in other parts of Taiwan. Therefore, we would like to report our observation about nontuberculous mycobacteria (NTM) in northern Taiwan. From January to December 2009, a total of 1,756 specimens from 898 patients positive for NTM were identified at the Mycobacteriology Laboratory at the National Taiwan University Hospital, a 2,500-bed tertiary care center in northern Taiwan that receives more than 6,000 daily clinical visits. The most common NTM isolates identified were MAC (579 isolates from 279 patients), followed by Mycobacterium abcesssus (275 isolates from 174 patients), and Mycobacterium fortuitum (258 isolates from 186 patients). Among the 279 patients from whom MAC was isolated,
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1
Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying Tainan, and 2Departments of Laboratory Medicine and Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan. *Correspondence to: Dr Po-Ren Hsueh, Departments of Laboratory Medicine and Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 100, Taiwan. E-mail: [email protected]
548
J Formos Med Assoc | 2011 • Vol 110 • No 8
Mycobacterium avium complex in northern Taiwan
14
Incidence of MAC disease
12 Incidence per 100,000 patients
12.3
Incidence of MAC colonization 10
10 8.5
8.8
8 6.4 5.5
6
4.8
4 2
1.9 0.8 0.5
0.9
1.4
1.3
1.5
1.3
2003 (328)
2004 (340)
2005 (449)
2006 (314)
1.6
2.1
0.2
0 2000 (102)
2001 (38)
2002 (244)
2007 (375)
2008 (571)
Number of MAC isolates Figure. The annual incidence (per 100,000 outpatients and inpatients) of patients with colonization and disease due to Mycobacterium avium complex (MAC).
significantly from 1.9 in 2000 to 12.3 in 2008 (p < 0.05). The annual incidence (per 100,000 inpatients and outpatients) of MAC disease also increased significantly from 0.5 in 2000 to 2.1 in 2008 (p < 0.05) (Figure). As for NTM pulmonary infection, MAC (35.3%) was the most common causative agent of pulmonary NTM infection during the study period. The annual incidence (per 100,000 inpatients and outpatients) of pulmonary MAC infection significantly increased from 1.63 in 2005 to 2.00 in 2008 at the National Taiwan University Hospital. Therefore, in addition to the increasing incidence of MAC colonization, we have demonstrated that the incidence of MAC diseases has gradually increased over time in northern Taiwan. This phenomenon might be attributable to increasing vigilance and awareness of these bacteria as human pathogens, improvements in diagnostic methods, and the
J Formos Med Assoc | 2011 • Vol 110 • No 8
increased population of immunocompromised patients. In conclusion, although most MAC isolates do not cause disease in humans, the incidence of MAC isolates in clinical specimens and the incidence of MAC diseases are gradually increasing in northern Taiwan.
References 1. Shen MC, Lee SJ, Huang TS, et al. Clinical significance of isolation of Mycobacterium avium complex from respiratory specimens. J Formos Med Assoc 2010;7:517–23. 2. Griffith DE, Aksamit T, Brow-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. 3. Lai CC, Tan CK, Chou CH, et al. Increasing incidence of nontuberculous mycobacteria, Taiwan, 2000–2008. Emerg Infect Dis 2010;16:294–6.
549
Contents lists available at ScienceDirect
Volume 110 Number 8 August 2011
Journal of the Formosan Medical Association
ISSN 0929 6646
Journal of the
Formosan Medical Association Resveratrol for prophylaxis of ischemic stroke Microglia and chronic pain ART in HIV-1-discordant couples in Taiwan Prognostic evaluation of patients with multicentric papillary thyroid microcarcinoma
Journal homepage: http://www.jfma-online.com
Formosan Medical Association Taipei, Taiwan
Letter to the Editor
Clinical Significance of Mycobacterium avium Complex Isolates at a Medical Center in Northern Taiwan Chong-Un Cheong,1 Chih-Cheng Lai,1 Po-Ren Hsueh2*
MAC colonization was noted in 210 (75.3%) patients, and MAC caused NTM disease in 69 (24.7%) patients, based on the 2007 criteria of the American Thoracic Society/Infectious Diseases Society of America.2 Those findings were consistent with those from our previous study conducted during the period January 2000 to December 2008 at the same institution.3 In that study, a total of 9,204 NTM isolates were recovered from 4,786 patients, and 2,761 isolates from 1,515 patients were confirmed to be MAC. Among those patients, MAC colonization was noted in 1,282 (84.6%) and MAC caused NTM diseases in 233 (15.4%). The annual prevalence of MAC colonization ranged from 80.0% (2000) to 87.4% (2006). These findings are consistent with those reported by Shen et al,1 namely that only 12 (22.2%) of 54 patients with positive MAC isolates had clinically significant MAC pulmonary disease. In addition, trend analysis has revealed that the annual incidence (per 100,000 inpatients and outpatients) of MAC colonization increased
We read with great interest the case report by Shen et al1 in the July 2010 issue of Journal of the Formosan Medical Association. In that retrospective study, the authors described the clinical significance of Mycobacterium avium complex (MAC) that had been isolated from respiratory specimens at a medical center in southern Taiwan. We wonder whether similar findings could be noted in other parts of Taiwan. Therefore, we would like to report our observation about nontuberculous mycobacteria (NTM) in northern Taiwan. From January to December 2009, a total of 1,756 specimens from 898 patients positive for NTM were identified at the Mycobacteriology Laboratory at the National Taiwan University Hospital, a 2,500-bed tertiary care center in northern Taiwan that receives more than 6,000 daily clinical visits. The most common NTM isolates identified were MAC (579 isolates from 279 patients), followed by Mycobacterium abcesssus (275 isolates from 174 patients), and Mycobacterium fortuitum (258 isolates from 186 patients). Among the 279 patients from whom MAC was isolated,
©2011 Elsevier & Formosan Medical Association .
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1
Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying Tainan, and 2Departments of Laboratory Medicine and Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan. *Correspondence to: Dr Po-Ren Hsueh, Departments of Laboratory Medicine and Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 100, Taiwan. E-mail: [email protected]
548
J Formos Med Assoc | 2011 • Vol 110 • No 8
Mycobacterium avium complex in northern Taiwan
14
Incidence of MAC disease
12 Incidence per 100,000 patients
12.3
Incidence of MAC colonization 10
10 8.5
8.8
8 6.4 5.5
6
4.8
4 2
1.9 0.8 0.5
0.9
1.4
1.3
1.5
1.3
2003 (328)
2004 (340)
2005 (449)
2006 (314)
1.6
2.1
0.2
0 2000 (102)
2001 (38)
2002 (244)
2007 (375)
2008 (571)
Number of MAC isolates Figure. The annual incidence (per 100,000 outpatients and inpatients) of patients with colonization and disease due to Mycobacterium avium complex (MAC).
significantly from 1.9 in 2000 to 12.3 in 2008 (p < 0.05). The annual incidence (per 100,000 inpatients and outpatients) of MAC disease also increased significantly from 0.5 in 2000 to 2.1 in 2008 (p < 0.05) (Figure). As for NTM pulmonary infection, MAC (35.3%) was the most common causative agent of pulmonary NTM infection during the study period. The annual incidence (per 100,000 inpatients and outpatients) of pulmonary MAC infection significantly increased from 1.63 in 2005 to 2.00 in 2008 at the National Taiwan University Hospital. Therefore, in addition to the increasing incidence of MAC colonization, we have demonstrated that the incidence of MAC diseases has gradually increased over time in northern Taiwan. This phenomenon might be attributable to increasing vigilance and awareness of these bacteria as human pathogens, improvements in diagnostic methods, and the
J Formos Med Assoc | 2011 • Vol 110 • No 8
increased population of immunocompromised patients. In conclusion, although most MAC isolates do not cause disease in humans, the incidence of MAC isolates in clinical specimens and the incidence of MAC diseases are gradually increasing in northern Taiwan.
References 1. Shen MC, Lee SJ, Huang TS, et al. Clinical significance of isolation of Mycobacterium avium complex from respiratory specimens. J Formos Med Assoc 2010;7:517–23. 2. Griffith DE, Aksamit T, Brow-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. 3. Lai CC, Tan CK, Chou CH, et al. Increasing incidence of nontuberculous mycobacteria, Taiwan, 2000–2008. Emerg Infect Dis 2010;16:294–6.
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