Heterogeneity and clonality among isolates of Mycobacterium kansasii: implications for epidemiological and pathogenicity studies

Abstract

The reservoir and transmission route of Mycobacterium kansasii are largely unknown. In addition, culturing of M. kansasii from human sources is not proof of disease because it may represent colonization rather than infection. Unfortunately, investigation of the epidemiology and pathogenicity of M. kansasii is complicated by evidence of heterogeneity within the species. A comprehensive study by detailed genotypic analysis of a large collection of M. kansasii isolates (n = 276) from various geographical sources within Europe was conducted. Five defined subtypes of M. kansasii were identified; of these subtypes, type I represents the most common isolate from humans. Although phylogenetic analysis confirmed its relationship to the other M. kansasii types, significant sequence divergence was found at the 16S-23S intergenic spacer. Analysis of the chromosomal polymorphism of type I demonstrated a marked clonal structure for this particular organism. Because M. kansasii is becoming a significant pathogen among immunodeficient hosts, future epidemiological and pathogenicity studies should take into consideration both the heterogeneity within the species and the apparent clonality of the most prevalent M. kansasii isolates infecting humans.

Comparative study of two typing methods,hsp65 PRA and ITS sequencing, revealed a possible evolutionary link betweenMycobacterium kansasiitype I and II isolates

“…This national survey showed that clinical isolates of Mycobacterium kansasii in Japan were almost exclusively of subtype I as determined from hsp65 PRA (Table 1). Similar results have been found in Europe (Alcaide et al, 1997;Picardeau et al, 1997;Taillard et al, 2003), North America (Zhang et al, 2004) and Sao Paulo, Brazil (Chimara et al, 2004).…”

“…The basis for the subtyping of M. kansasii by the commercially available INNO-LiPA Mycobacteria v2 test (Innogenetics, Ghent, Belgium) is ITS sequence. Although some reports have indicated that subtyping results derived from hsp65 PRA and ITS sequencing are concordant (Alcaide et al, 1997;Richter et al, 1999), the sample number used was not sufficient to unequivocally support it. Comprehensive analysis to verify the relationship between subtyping by hsp65 PRA and ITS sequencing is required to avoid any potential ambiguities and confusion concerning clinical significance and epidemiological studies of M. kansasii based on its genotype.…”

“…Briefly, the Telenti fragment (441 bp) was amplified using primers TB11 and TB12 and digested with BstEII and HaeIII. Restriction fragment lengths were analyzed using the HITACHI microchip electrophoresis analysis system i-chip SV1210 (Hitachi electronics engineering Co. Ltd., Tokyo, Japan), which provides digital images, and banding patterns were characterized according to previously used methods (Alcaide et al, 1997;Picardeau et al, 1997). All banding patterns obtained in this study are depicted in Fig.…”

“…Mycobacterium kansasii is one of the most frequently isolated nontuberculous mycobacterial pathogen from clinical specimens (Choudhri et al, 1995). Molecular typing methods demonstrated that M. kansasii is a heterogeneous species with several distinct subtypes (Ross et al, 1992;Alcaide et al, 1997;Iinuma et al, 1997;Picardeau et al, 1997;Richter et al, 1999;Gaafar et al, 2003;Taillard et al, 2003). PCR and restriction enzyme analysis (PRA) of the hsp-65 gene has been widely applied to studies concerning M. kansasii genotypic characterization (Ross et al, 1992;Picardeau et al, 1997;Richter et al, 1999;Taillard et al, 2003;Chimara et al, 2004).…”

“…Besides hsp65 PRA, the 16S-23S internal transcribed spacer (ITS) region is considered a useful genomic marker for the subtyping of M. kansasii (Roth et al, 1998(Roth et al, , 2000. Certain researchers have demonstrated that grouping into subspecies on the basis of the ITS is consistent with genotyping on the basis of hsp65 PRA (Alcaide et al, 1997;Richter et al, 1999). The basis for the subtyping of M. kansasii by the commercially available INNO-LiPA Mycobacteria v2 test (Innogenetics, Ghent, Belgium) is ITS sequence.…”