Transmission of tuberculosis from smear negative patients: a molecular epidemiology study

Hernández-Gargard&ño, E.; Cook, V.; Kunimoto, D.; Elwood, R. K.; Black, W. A.; FilzGerald, J. M.
April 2004
Thorax;Apr2004, Vol. 59 Issue 4, p286
Academic Journal
Background: While smear positive patients with tuberculosis (TB) are considered more infectious than smear negative patients, the latter can also transmit TB. Methods: In a molecular epidemiology study of 791 patients in the Greater Vancouver regional district, the number of episodes of TB transmission from two groups of smear negative clustered patients by RFLP (assumed to be involved in recent transmission) was estimated after assessing for potential bias. Group 1 (n = 79) included patients with pulmonary TB or pulmonary + extrapulmonary disease (PTB or PTB+EPTB); group 2 (n = 129) included all patients in group 1 + extrapulmonary cases alone. Results: In the total sample the mean (SD) age was 51 (21) years, 54.3% were male, and 17.0% of patients were clustered. Compared with smear negative patients, smear positive patients were more likely to be in a cluster (OR = 2.0, 95% Cl 1.1 to 3.6) and to have had a history of ethanol abuse (OR = 2.7, 95% Cl 1 .0 to 6.7), diabetes mellitus (OR = 2.8, 95% Cl 1 .1 to 7.0), injection drug use (OR = 3.1, 95% CI 1 .1 to 8.3), and to have had a previous hospital admission (OR=8.5, 95% CI 5.1 to 14.0). The proportion of episodes of transmission from smear negative clustered patients ranged from 17.3% to 22.2% in group 1 and from 25% to 41% in group 2. Conclusion: In Greater Vancouver, smear negative cases appear responsible for at least one sixth of culture positive episodes of TB transmission.


Related Articles

  • Transmission of Mycobacterium tuberculosis in China: A Population-Based Molecular Epidemiologic Study. Chongguang Yang; Xin Shen; Ying Peng; Rushu Lan; Yuling Zhao; Bo Long; Tao Luo; Guomei Sun; Xia Li; Ke Qiao; Xiaohong Gui; Jie Wu; Jiying Xu; Fabin Li; Dingyue Li; Feiying Liu; Mei Shen; Jianjun Hong; Jian Mei; DeRiemer, Kathryn // Clinical Infectious Diseases;7/15/2015, Vol. 61 Issue 2, p219 

    Background: Understanding the transmission of Mycobacterium tuberculosis is essential for the development of efficient tuberculosis control strategies. China has the second-largest tuberculosis burden in the world. Recent transmission and infection with M. tuberculosis, particularly...

  • Use of cluster-graphs from spoligotyping data to study genotype similarities and a comparison of three indices to quantify recent tuberculosis transmission among culture positive cases in French Guiana during a eight year period. Guernier, Vanina; Sola, Christophe; Brudey, Karine; Guégan, Jean-François; Rastogi, Nalin // BMC Infectious Diseases;2008, Vol. 8 Issue 1, Special section p1 

    Background: French Guiana has the highest tuberculosis (TB) burden among all French departments, with a strong increase in the TB incidence over the last few years. It is now uncertain how best to explain this incidence. The objective of this study was to compare three different methods...

  • Molecular Epidemiology of Tuberculosis in a Low- to Moderate-Incidence State: Are Contact investigations Enough? Cronin, Wendy A.; Golub, Jonathan E.; Lathan, Monica J.; Mukasa, Leonard N.; Hooper, Nancy; Razeq, Jafar H.; Baruch, Nancy G.; Mulcahy, Donna; Benjamin, William H.; Magder, Laurence S.; Strickland, G. Thomas; Bishai, William R. // Emerging Infectious Diseases;Nov2002, Vol. 8 Issue 11, p1271 

    Examines the molecular epidemiology of tuberculosis (TB) in sites with a low-to-moderate disease incidence in Maryland. Comparison between traditional and nontraditional transmission settings; Identification of the transmission of TB before and after genotyping; Details on the program...

  • Influence of Sampling on Clustering and Associations With Risk Factors in the Molecular Epidemiology of Tuberculosis. Borgdorff, Martien W.; van den Hof, Susan; Kalisvaart, Nico; Kremer, Kristin; van Soolingen, Dick // American Journal of Epidemiology;Jul2011, Vol. 174 Issue 2, p243 

    Molecular epidemiologic studies may use genotypic clustering of isolates as an indicator of recent transmission. It has been shown that missing cases lead to underestimating clustering, and modelling studies suggested that they may also lead to underestimating odds ratios for clustering. Using a...

  • Data mining cluster analysis on the influence of health factors in Casemix data. Kaur, Harleen; Chauhan, Ritu; Aljunid, Syed Mohamed // BMC Health Services Research;2012, Vol. 12 Issue Suppl 1, p1 

    The article presents an observational study on cases registered to California Department of Alcohol and Drug Programs (ADP) which explores possible applications of data mining in the Casemix context. The study adopts data mining tools such as K-means and Hierarchical Clustering technique using...

  • A Tuberculosis Outbreak Fueled by Cross-Border Travel and Illicit Substances: Nevada and Arizona. KIREN MITRUKA; BLAKE, HALEY; RICKS, PHILIP; MIRAMONTES, ROQUE; BAMRAH, SAPNA; CHEE, CARLA; HICKSTEIN, LAURIE // Public Health Reports;Jan/Feb2014, Vol. 129 Issue 1, p78 

    Objectives. From May 2006 to August 2008, the Southern Nevada Health District identified eight tuberculosis (TB) cases in six adults and two children in a Hispanic community. We conducted an outbreak investigation to determine the extent of TB transmission and prevent additional cases. Methods....

  • Clustering of Mycobacterium tuberculosis Cases in Acapulco: Spoligotyping and Risk Factors. Nava-Aguilera, Elizabeth; López-Vidal, Yolanda; Harris, Eva; Morales-Pérez, Arcadio; Mitchell, Steven; Flores-Moreno, Miguel; Villegas-Arrizon, Ascencio; Legorreta-Soberanis, José; Ledogar, Robert; Andersson, Neil // Clinical & Developmental Immunology;2011, p1 

    Recurrence and reinfection of tuberculosis have quite different implications for prevention. We identified 267 spoligotypes of Mycobacterium tuberculosis from consecutive tuberculosis patients in Acapulco, Mexico, to assess the level of clustering and risk factors for clustered strains. Point...

  • Sampling bias in the molecular epidemiology of tuberculosis. Murray, Megan // Emerging Infectious Diseases;Apr2002, Vol. 8 Issue 4, p363 

    Among the goals of the molecular epidemiology of infectious disease are to quantify the extent of ongoing transmission of infectious agents and to identify host- and strain-specific risk factors for disease spread. I demonstrate the potential bias in estimates of recent transmission and the...

  • Identifying the Sources of Tuberculosis in Young Children: A Multistate Investigation. Sun, Sumi J.; Bennett, Dianne E.; Flood, Jennifer; Loeffler, Ann M.; Kammerer, Steve; Ellis, Barbara A. // Emerging Infectious Diseases;Nov2002, Vol. 8 Issue 11, p1216 

    Analyzes the molecular epidemiology of tuberculosis (TB) transmission in young children in the U.S. Details on the frequency of suspected source patients identified for young children; Characteristics of source patients; Assessment of the proportion of isolates from young children; Information...


Read the Article


Sign out of this library

Other Topics