Enhanced molecular typing of treponema pallidum: geographical distribution of strain types and association with neurosyphilis.
BACKGROUND
Strain typing is a tool for determining the diversity and epidemiology of infections.


METHODS
Treponema pallidum DNA was isolated from 158 patients with syphilis from the United States, China, Ireland, and Madagascar and from 15 T. pallidum isolates. Six typing targets were assessed: (1) the number of 60‐bp repeats in the acidic repeat protein gene, (2) restriction fragment length polymorphism (RFLP) analysis of T. pallidum repeat (tpr) subfamily II genes, (3) RFLP analysis of the tprC gene, (4) determination of tprD allele in the tprD gene locus, (5) the presence of a 51‐bp insertion between tp0126 and tp0127, and (6) sequence analysis of an 84‐bp region of tp0548. The combination of targets 1 and 2 comprises the Centers for Disease Control and Prevention (CDC) T. pallidum subtyping method.


RESULTS
Adding sequence analysis of tp0548 to the CDC method yielded the most discriminating typing system. Twenty‐five strain types were identified and designated as "CDC subtype/tp0548 sequence type." Type 14d/f was found in samples from 5 of 6 locations. In Seattle, Washington, strain types changed from 1999 through 2008 (P < .001). Twenty‐one (50%) of 42 patients infected with type 14d/f had neurosyphilis compared with 10 (24%) of 41 patients infected with any of the other types combined (P = .02).


CONCLUSIONS
We describe an enhanced T. pallidum strain typing system that shows biological and clinical relevance.
Marra
Christina  M
C
Departments of Neurology, University of Washington School of Medicine, Seattle, Washington 98104‐2499, USA.
Sahi
Sharon  K
S
Tantalo
Lauren  C
L
Godornes
Charmie
C
Reid
Tara
T
Behets
Frieda
F
Rompalo
Anne
A
Klausner
Jeffrey D
JD
Yin
Yue  Ping
Y
Mulcahy
Fiona
F
Golden
Matthew R
MR
Centurion-Lara
Arturo
A
Lukehart
Sheila A
SA
D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002681:China; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D007494:Ireland; D008270:Madagascar; D008297:Male; D017720:Molecular Epidemiology / Q000379:methods; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D013587:Syphilis / Q000382:microbiology*; D014210:Treponema pallidum / Q000145:classification* / Q000302:isolation & purification*; D014481:United States
D001426:Bacterial Proteins; D004269:DNA, Bacterial