<prompt> A newborn premature baby presented with bullous lesions on skin and legs, Xray shows features suggestive of periostitis. Which of the following is the initial investigation?VDRL testFTA-ABS testTPHA testculture  <response>: The newborn baby has characteristic signs and symptoms of congenital syphilis. Periostitis is a hallmark of skeletal manifestation. VDRLRPR is the initial investigation of choice in congenital syphilis. All neonates born to mothers who have reactive nontreponemal and treponemal test results should be evaluated with a quantitative nontreponemal serologic test RPR or VDRL performed on the neonates serum, because umbilical cord blood can become contaminated with maternal blood and yield a false-positive result. FTA-ABSTPHA are used for confirmation of syphilis in a patient with reactive RPRVDRL test. T. pallidum cannot be detected by culture. Reference: Ananthanarayan and Paniker;s Textbook of Microbiology Tenth edition 