Man-Li Tong1, Hui-Lin Zhang1, Xiao-Zhen Zhu1, Jin-Yi Fan1, Kun Gao1, Li-Rong Lin1, Li-Li Liu1, Shu-Lian Li2, Hui-Ling Lin2, Zhi-Feng Lin2, Jian-Jun Niu3, Wei-Hong Zheng4, Tian-Ci Yang5. 1. Clinical Laboratory, Zhongshan Hospital, Medical College of Xiamen University, Xiamen 361004, China. 2. Department of Gynaecology and Obstetrics, Xiamen Huli District Maternity and Child Care Hospital, Xiamen 361000, China. 3. Clinical Laboratory, Zhongshan Hospital, Medical College of Xiamen University, Xiamen 361004, China; Department of Hospital Infection and Medical Healthy Care, Xiamen Zhongshan Hospital, Fujian Medical University, Xiamen 361004, China. 4. Department of Neurology, Medical College of Xiamen University, Xiamen 361004, China. Electronic address: zwh610547@xmu.edu.cn. 5. Clinical Laboratory, Zhongshan Hospital, Medical College of Xiamen University, Xiamen 361004, China. Electronic address: yangtianci@xmu.edu.cn.
Abstract
BACKGROUND: The rabbit infectivity test (RIT) was previously described as a highly-sensitive method for clinically detecting Treponema pallidum. But our primary study indicated this result may have changed in current antibiotics era. METHODS: By inoculating rabbits testis with cerebrospinal fluid (CSF) (n=63) and exudate from hard chancre lesions (n=13), we re-evaluated the sensitivity of RIT in modern era. All isolated T. pallidum strains from the RIT were performed for the strain type based on "CDC subtype/tp0548" method. Chi-square and Fisher's exact tests were used to determine the statistical significance of differences across data sets. RESULTS: Result indicated that 2 of 63 CSF (2/63, 3.17%) and 5 of 13 lesion exudate samples (5/13, 38.47%) were positive in the RIT, with a much longer time to detection for CSF samples. Only 1 of 28 samples from patients who admitted treatment with antibiotics prior to clinical exam was positive in the RIT; while 6 of 48 patients, who admitted no recent exposure to antibiotics or was unclear about the medical history, were positive in RIT. DNA sequence analysis revealed 6 strains of 14d/f subtype and one strain of 14a/f subtype. CONCLUSIONS: In conclusions, RIT is no longer a highly sensitive method for detecting T. pallidum in clinical samples as before, and is not inadequately considered to be a reference method for measuring the sensitivity of other new methods, such as the PCR. These data represent the first reexamination of the sensitivity of RIT in the post-antibiotic era with a large clinical sample.
BACKGROUND: The rabbit infectivity test (RIT) was previously described as a highly-sensitive method for clinically detecting Treponema pallidum. But our primary study indicated this result may have changed in current antibiotics era. METHODS: By inoculating rabbits testis with cerebrospinal fluid (CSF) (n=63) and exudate from hard chancre lesions (n=13), we re-evaluated the sensitivity of RIT in modern era. All isolated T. pallidum strains from the RIT were performed for the strain type based on "CDC subtype/tp0548" method. Chi-square and Fisher's exact tests were used to determine the statistical significance of differences across data sets. RESULTS: Result indicated that 2 of 63 CSF (2/63, 3.17%) and 5 of 13 lesion exudate samples (5/13, 38.47%) were positive in the RIT, with a much longer time to detection for CSF samples. Only 1 of 28 samples from patients who admitted treatment with antibiotics prior to clinical exam was positive in the RIT; while 6 of 48 patients, who admitted no recent exposure to antibiotics or was unclear about the medical history, were positive in RIT. DNA sequence analysis revealed 6 strains of 14d/f subtype and one strain of 14a/f subtype. CONCLUSIONS: In conclusions, RIT is no longer a highly sensitive method for detecting T. pallidum in clinical samples as before, and is not inadequately considered to be a reference method for measuring the sensitivity of other new methods, such as the PCR. These data represent the first reexamination of the sensitivity of RIT in the post-antibiotic era with a large clinical sample.
Authors: Lara E Pereira; Samantha S Katz; Yongcheng Sun; Patrick Mills; Willie Taylor; Patricia Atkins; Charles M Thurlow; Kai-Hua Chi; Damien Danavall; Nicholas Cook; Tamanna Ahmed; Alyssa Debra; Susan Philip; Stephanie Cohen; Kimberly A Workowski; Ellen Kersh; Yetunde Fakile; Cheng Y Chen; Allan Pillay Journal: PLoS One Date: 2020-01-13 Impact factor: 3.240