Background. Sputum smear-positive pulmonary tuberculosis patients expel infectious viable bacilli for a period following the commencement of treatment. Objective. To determine the time to sputum smear conversion and study the factors influencing it. Design. A prospective study was undertaken at our hospital in Rabat over a six-month period on a cohort of 119 sputum smear positive patients. Patients were followed up fortnightly. At each followup, specimens were collected and processed for microscopy using standard protocol. Results. 96.6% of our patients completed the study (4 deaths). Sputum conversion rate was 42% after two weeks, 73% after one month, and 95% after two months. Univariate and stepwise regression analysis showed that patients who had high smear grading, miliary, and bilateral radiologic lesions were more likely to undergo delayed sputum conversion ( ). Other factors were thought to influence sputum conversion but were not statistically proven in our study. Conclusion. Since viable bacilli continue to be expelled for up to two months, infection control measures should be maintained for such a time. Patients with high smear grading, miliary, and bilateral radiologic lesions need to be monitored more closely. 1. Introduction The World Health Organization (WHO) estimates that there are almost 13.7 milion people living with tuberculosis and that the disease kills more young people and adults than any other infectious disease in the world. In Morocco, the new cases of tuberculosis in 2008 were 27000, and the incidence was 82/100000 people. Patients in our health system receive intermittent therapy with multidrug regimen based on directly observed treatment, short-course (DOTS). Tuberculosis control aims to reduce the spread of the infection, and the most efficient method for preventing transmission is the identification and cure of infectious pulmonary tuberculosis patients [1]. Sputum smear-positive (SSP) pulmonary tuberculosis patients are the most significant source of infection for tuberculosis because, when they cough or sneeze, they expel droplet nuclei which carry infectious bacilli [2]. One untreated infectious tuberculosis patient is likely to infect 10 to 15 persons annually [3]. When SSP patients are initiated on multidrug antituberculosis treatment, there is a multifold reduction in bacillary load expelled in sputum [4]. Patients, who respond, are likely to become smear and culture negative during the course of treatment. However, viable bacilli continue to be expelled for a period of time, during which they may continue to spread
References
[1]
Z. Feng-Zeng, M. H. Levy, and W. Sumin, “Sputum microscopy results at two and three months predict outcome of tuberculosis treatment,” International Journal of Tuberculosis and Lung Disease, vol. 1, no. 6, pp. 570–572, 1997.
[2]
Centers for Disease Control and Prevention, “Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care settings, 2005,” Morbidity and Mortality Weekly Report, vol. 54, no. 17, pp. 1–141, 2005.
[3]
S. P. Agarwal and L. S. Chauhan, Tuberculosis Control in India, Directorate General of Health Services, Ministry of Health and Family Welfare, Government of India, New Delhi, India, 2005.
[4]
A. F. Sirgel, J. Odhiambo, W. Githui et al., “A multicentre study of the early bactericidal activity of anti-tuberculosis drugs,” Journal of Antimicrobial Chemotherapy, vol. 45, no. 6, pp. 859–870, 2000.
[5]
T. Frieden, Ed., Toman’s Tuberculosis Case Detection, Treatment, and Monitoring—Questions and Answers, World Health Organisation, Geneva, Switzerland, 2nd edition, 2004.
[6]
R. Long, K. Bochar, S. Chomyc et al., “Relative versus absolute noncontagiousness of respiratory Tuberculosis on treatment,” Infection Control and Hospital Epidemiology, vol. 24, no. 11, pp. 823–838, 2003.
[7]
Stop TB Department and World Health Organization, WHO Policy on TB infection control in healthcare-care facilities, congregate settings and households, World Health Organization, Geneva, Switzerland, 2009.
[8]
P. Raunak, N. Gita, K. Swapna, K. Vijay, and M. Preeti, “Time to sputum conversion in smear positive pulmonary TB patients on category I DOTS and factors delaying it,” The Journal of the Association of Physicians of India, vol. 60, pp. 22–26, 2012.
[9]
B. A. Fazal, E. E. Telzak, S. Blum et al., “Impact of a coordinated tuberculosis team in an inner-city hospital in New York City,” Infection Control and Hospital Epidemiolog, vol. 16, no. 6, pp. 340–343, 1995.
[10]
World Health Organization, “Global tuberculosis control: epidemiology, planning, financing,” WHO Report 2009, World Health Organization, Geneva, Switzerland, 2009.
[11]
H. L. Rieder, “Sputum smear conversion during directly observed treatment for tuberculosis,” Tubercle and Lung Disease, vol. 77, no. 2, pp. 124–129, 1996.
[12]
Z. Feng-Zeng, M. H. Levy, and W. Sumin, “Sputum microscopy results at two and three months predict outcome of tuberculosis treatment,” International Journal of Tuberculosis and Lung Disease, vol. 1, no. 6, pp. 570–572, 1997.
[13]
C. Lienhardt, K. Manneh, V. Bouchier, G. Lahai, P. J. M. Milligan, and K. P. W. J. McAdam, “Factors determining the outcome of treatment of adult smear-positive tuberculosis cases in the Gambia,” International Journal of Tuberculosis and Lung Disease, vol. 2, no. 9, pp. 712–718, 1998.
[14]
C. Kuaban, R. Bame, L. Mouangue, S. Djella, and C. Yomgni, “Non conversion of sputum smears in new smear positive pulmonary tuberculosis patients in Yaoundé, Cameroon,” East African Medical Journal, vol. 86, no. 5, pp. 219–225, 2009.
[15]
A. Domínguez-Castellano, M. A. Muniain, J. Rodriguez-Ba？o et al., “Factors associated with time to sputum smear conversion in active pulmonary tuberculosis,” International Journal of Tuberculosis and Lung Disease, vol. 7, no. 5, pp. 432–438, 2003.
[16]
M. Güler, E. ünsal, B. Dursun, et al., “Factors influencing sputum smear and culture conversion time among patients with new case pulmonary tuberculosis,” International Journal of Clinical Practice, vol. 61, no. 2, pp. 231–235, 2007.
[17]
M. Senkoro, S. G. Mfinanga, and O. M？rkve, “Smear microscopy and culture conversion rates among smear positive pulmonary tuberculosis patients by HIV status in Dar es Salaam, Tanzania,” BMC Infectious Diseases, vol. 10, article 210, 2010.
[18]
B. Dautzenberg, “Tuberculose : prévention, isolement, hygiène,” Médecine et Maladies Infectieuses, vol. 25, no. 3, pp. 392–401, 1995.
[19]
Tuberculosis: Clinical diagnosis and management of tuberculosis, and measures for its prevention and control. Exelence NIfHaC, The National Collaborating Centre for Chronic Conditions 2006.
[20]
R. Singla, M. M. Osman, N. Khan, N. Al-Sharif, M. O. Al-Sayegh, and M. A. Shaikh, “Factors predicting persistent sputum smear positivity among pulmonary tuberculosis patients 2 months after treatment,” International Journal of Tuberculosis and Lung Disease, vol. 7, no. 1, pp. 58–64, 2003.
[21]
E. E. Telzak, B. A. Fazal, C. L. Pollard, G. S. Turett, J. E. Justman, and S. Blum, “Factors influencing time to sputum conversion among patients with smear-positive pulmonary tuberculosis,” Clinical Infectious Diseases, vol. 25, no. 3, pp. 666–672, 1997.
[22]
V. V. Banu Rekha, R. Balasubramanian, S. Swaminathan et al., “Sputum conversion at the end of intensive phase of Category-1 regimen in the treatment of pulmonary tuberculosis patients with diabetes mellitus or HIV infection: an analysis of risk factors,” Indian Journal of Medical Research, vol. 126, no. 5, pp. 452–458, 2007.
[23]
J. Hiyama, M. Marukawa, Y. Shiota, et al., “Factors influencing response to treatment of pulmonary tuberculosis,” Acta Medica Okayama, vol. 54, no. 4, pp. 139–145, 2000.
[24]
J. Y. Wang, L. N. Lee, C. J. Yu, Y. J. Chien, P. C. Yang, and Tami Group, “Factors influencing time to smear conversion in patients with smear-positive pulmonary tuberculosis,” Respirology, vol. 14, no. 7, pp. 1012–1019, 2009.
[25]
D. J. Horne, C. O. Johnson, E. Oren, C. Spitters, and M. Narita, “How soon should patients with smear-positive tuberculosis be released from inpatient isolation?” Infection Control and Hospital Epidemiology, vol. 31, no. 1, pp. 78–84, 2010.
[26]
G. M. Cauthen, S. W. Dooley, I. M. Onorato et al., “Transmission of Mycobacterium tuberculosis from tuberculosis patients with HIV infection or AIDS,” American Journal of Epidemiology, vol. 144, no. 1, pp. 69–77, 1996.
[27]
A. Domínguez-Castellano, M. A. Muniain, J. Rodriguez-Ba？o et al., “Factors associated with time to sputum smear conversion in active pulmonary tuberculosis,” International Journal of Tuberculosis and Lung Disease, vol. 7, no. 5, pp. 432–438, 2003.
[28]
R. Singla, N. Khan, N. Al-Sharif, M. O. Al-Sayegh, M. A. Shaikh, and M. M. Osman, “Influence of diabetes on manifestations and treatment outcome of pulmonary TB patients,” International Journal of Tuberculosis and Lung Disease, vol. 10, no. 1, pp. 74–79, 2006.
[29]
Z. Liu, K. L. Shilkret, and H. M. Ellis, “Predictors of sputum culture conversion among patients with tuberculosis in the era of tuberculosis resurgence,” Archives of Internal Medicine, vol. 159, no. 10, pp. 1110–1116, 1999.
[30]
K. Slama, C. Y. Chiang, D. A. Enarson et al., “Tobacco and tuberculosis: a qualitative systematic review and meta-analysis,” International Journal of Tuberculosis and Lung Disease, vol. 11, no. 10, pp. 1049–1061, 2007.
[31]
C. C. Leung, W. W. Yew, C. K. Chan et al., “Smoking and tuberculosis in Hong Kong,” International Journal of Tuberculosis and Lung Disease, vol. 7, no. 10, pp. 980–986, 2003.
[32]
A. T. Abal, B. Jayakrishnan, S. Parwer, A. El Shamy, E. Abahussain, and P. N. Sharma, “Effect of cigarette smoking on sputum smear conversion in adults with active pulmonary tuberculosis,” Respiratory Medicine, vol. 99, no. 4, pp. 415–420, 2005.
[33]
Durban Immunotherapy Trial Group, “Immunotherapy with Mycobacterium vaccae in patients with newly diagnosed pulmonary tuberculosis: a randomised controlled trial,” The Lancet, vol. 354, no. 9173, pp. 116–119, 1999.
