Home Thrust Areas Projects Publications Training Scientists Director   Andamans

  Molecular characterization of leptospiral isolates using RAPD fingerprinting

Fig 1. RAPD fingerprints of reference strains belonging to different serogroups
 

Dendrogram showing phylogenetic relationship between different serogroups

 Lanes:

1. Andamana,

8. Hebdomadis,

2. Australis,

9. Icterohaemorrhagiae,

3. Autumnalis,

10. Panama,

4. Ballum,

11. Pomona,  

5. Canicola

12. Shermani,

6. Cynopteri,

13. Sejroe,  

7. Grippotyphosa,

14. Semaranga
   

Fig 2. RAPD fingerprints of reference strains of different serovars of serogroup Grippotyphosa

 

Dendrogram showing relationship between different

serovars of serogroup Grippotyphosa

Lanes:

1. Valbuzzi

6. Huanuco

2. Vanderhoedeni

7. Canalzonae

3. Bananal

8. Mulleri

4. Dadas

9. Ratnapura

5. Liangg

 
   

Fig 3. RAPD fingerprints of (A) two reference strains serovar Autumnalis and (B) Grippotyphosa

  

 

 

 

 

 

 

 

  

Fig 4. RAPD fingerprints of local isolates.    Patterns matching with that of reference strains indicated

 

Fig 5. RAPD fingerprints of local isolates. Patterns matching with that of reference strains indicated (R7: Grippotyphosa CH 31, R8: Hebdomedis, R11: Pomona, R13: Sejroe Hardjopraj)

Twenty-six reference strains of different serovars and 24 isolates obtained from patients in Andaman were characterized using RAPD. All the isolates were screened against 36 group specific antisera representing 23 serogroups to identify the serogroup. Genomic DNA was isolated from the isolates and reference strains. Five primers viz. L10, M13, P1, PB1 and S6 were used to generate RAPD fingerprints. Phylogenetic analysis was done using Bio-gene software.

RAPD produced characteristic banding patterns for different reference strains. It was able to differentiate between strains of different serogroups (fig. 1 & 2), serovars (fig. 3 & 4) and even within the same serovar (fig. 5). Twenty-two out of the 24 isolates could be typed by this method and the results were similar with those obtained serologically by MAT (fig. 4 & 5).

   

However, for one isolate, the genetic fingerprint was identical with Pomona, while serologically it was found to be related to Autumnalis. Fingerprint pattern of another isolate (AHF421) could not be matched with any of the reference strains used in the study though serologically it was found to belong to Sejroe serogroup. RAPD fingerprinting was found to be highly discriminatory and can be a very useful tool in characterization of Leptospira isolates even between different serovars of the same serogroup and even between members of the same serovar. However, since genetic classification does not always match with serological classification, they should be viewed independently from each other.