TY - JOUR
T1 - Recurrent tuberculosis in patients infected with the predominant Mycobacterium tuberculosis outbreak strain in Denmark. New insights gained through whole genome sequencing
AU - Folkvardsen, Dorte Bek
AU - Norman, Anders
AU - Rasmussen, Erik Michael
AU - Lillebaek, Troels
AU - Jelsbak, Lars
AU - Andersen, Åse Bengård
N1 - Copyright © 2020 Elsevier B.V. All rights reserved.
PY - 2020/6
Y1 - 2020/6
N2 - OBJECTIVES: Recurrent tuberculosis (TB) is defined by more than one TB episode per patient and is caused by reinfection with a new M. tuberculosis (Mtb) strain or relapse with the previous strain. In Denmark, a major TB outbreak caused by one specific Mtb genotype "DKC2" is ongoing. Of the 892 patients infected with DKC2 between 1992 and 2014, 32 had recurrent TB with 67 TB episodes in total.METHODS: The 32 cases were evaluated in terms of number of single-nucleotide polymorphism (SNP) differences and time between episodes derived from whole-genome sequencing data.RESULTS: For four TB cases, the subsequent episodes could be confirmed as relapse and for one case as reinfection. Eight cases with SNP differences <6, theoretically indicating relapse, could be classified as likely reinfections based on phylogenetic analysis in combination with geographical data. Subsequent TB episodes for the remaining 19 cases could not be classified as relapse or reinfection even though they all had a SNP difference of <6 SNPs.CONCLUSIONS: In newer studies, investigating recurrent TB with the use of WGS, the number of SNPs has been used to distinguish between relapse and reinfection. The algorithm proposed for this is not valid in the Danish TB outbreak setting as our findings challenge the interpretation of few SNP differences as representing relapse. However, when including phylogenetic analysis and geographical data in the analysis, classification of 13 of the 32 cases were possible.
AB - OBJECTIVES: Recurrent tuberculosis (TB) is defined by more than one TB episode per patient and is caused by reinfection with a new M. tuberculosis (Mtb) strain or relapse with the previous strain. In Denmark, a major TB outbreak caused by one specific Mtb genotype "DKC2" is ongoing. Of the 892 patients infected with DKC2 between 1992 and 2014, 32 had recurrent TB with 67 TB episodes in total.METHODS: The 32 cases were evaluated in terms of number of single-nucleotide polymorphism (SNP) differences and time between episodes derived from whole-genome sequencing data.RESULTS: For four TB cases, the subsequent episodes could be confirmed as relapse and for one case as reinfection. Eight cases with SNP differences <6, theoretically indicating relapse, could be classified as likely reinfections based on phylogenetic analysis in combination with geographical data. Subsequent TB episodes for the remaining 19 cases could not be classified as relapse or reinfection even though they all had a SNP difference of <6 SNPs.CONCLUSIONS: In newer studies, investigating recurrent TB with the use of WGS, the number of SNPs has been used to distinguish between relapse and reinfection. The algorithm proposed for this is not valid in the Danish TB outbreak setting as our findings challenge the interpretation of few SNP differences as representing relapse. However, when including phylogenetic analysis and geographical data in the analysis, classification of 13 of the 32 cases were possible.
KW - Network
KW - Recurrence
KW - Reinfection
KW - Relapse
KW - Tuberculosis
KW - WGS
U2 - 10.1016/j.meegid.2020.104169
DO - 10.1016/j.meegid.2020.104169
M3 - Journal article
C2 - 31918042
SN - 1567-1348
VL - 80
SP - 104169
JO - Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases
JF - Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases
ER -