Allan Pillay - Academia.edu (original) (raw)

Papers by Allan Pillay

Diagnostic Microbiology and Infectious Disease, Aug 1, 2001

Previous reports suggest that Treponema pallidum bacteremia occurs in persons with syphilis expos... more Previous reports suggest that Treponema pallidum bacteremia occurs in persons with syphilis exposure ('incubating syphilis') and in persons with primary or secondary syphilis. During a recent syphilis outbreak, whole blood samples from 32 persons with suspected syphilis or syphilis exposure were screened using polymerase chain reaction (PCR) to amplify the DNA polymerase I gene (polA) of T. pallidum. Of the 32 samples, polA was amplified from 13 (41%). Of these 13, three were determined to have incubating syphilis; two had primary or secondary syphilis and eight had latent syphilis. This study demonstrates that spirochetemia can occur throughout the course of T. pallidum infection.

2014 National STD Prevention Conference, Jun 11, 2014

ABSTRACT Background: Proficiency in serological testing is essential to accurately diagnose syphi... more ABSTRACT Background: Proficiency in serological testing is essential to accurately diagnose syphilis. CDC administers a syphilis serology proficiency testing (PT) program worldwide in its role as a WHO/PAHO Collaborating Centre for STD Diagnostics and Surveillance. Methods:CDC sends a serum panel of known results to 78 laboratories worldwide. Participating laboratories perform treponemal (TPPA, MHA-TP, TPHA, FTA-ABS, EIA) and non-treponemal (VDRL, USR, RPR) qualitative and quantitative tests, reporting results to CDC for analysis and feedback. Results: In 2012, 51(65.4%) of the 78 laboratories reported PT results on at least one serologic test (third panel). Qualitative VDRL and RPR non-treponemal test results from responding laboratories were comparable to those of 3 CDC reference laboratories (Georgia PHL; the Texas Department of State Health Services; and the Syphilis Serology Laboratory, CDC) for most VDRL and RPR samples. For the qualitative VDRL, scores averaged 98.7 %, with 1 of 31(3.2%) reporting laboratories failing. Scores for the qualitative RPR averaged 99.4%, with 1 of 36 (2.7%) laboratories failing. For the quantitative VDRL and RPR, low scores were due to reported titers being too high or too low. Scores for the quantitative VDRL averaged 94.1%, with 3 of 29(10.3%) laboratories failing. Scores for the quantitative RPR averaged 94%, with 6 of 32(18.8 %) laboratories failing. For treponemal tests, the 42 laboratories performing the MHA-TP, TPHA, or TPPA averaged 98.6%; 3 (7.2%) laboratories failed. For FTA-ABS, 22 laboratories averaged 100%. For the EIA-IgG test, 18 laboratories averaged 98.9% with 1 (5.6%) not achieving an acceptable result. Conclusions: Laboratories participating in the syphilis PT program do well in treponemal and qualitative non-treponemal testing. However, several had problems in quantitative non-treponemal tests suggesting training or other capacity building options may be beneficial. Criteria for PT program inclusion should be revisited due to lack of reporting from a number of laboratories.

Humana Press eBooks, Oct 10, 2012

Journal of Clinical Microbiology, Oct 1, 1996

Local strains of Haemophilus ducreyi were characterized by ribosomal DNA fingerprinting in order ... more Local strains of Haemophilus ducreyi were characterized by ribosomal DNA fingerprinting in order to develop a typing scheme for this organism. Chromosomal DNAs from 30 strains were extracted, and restriction fragments were separated by agarose gel electrophoresis after cleavage with BglII, HindIII, HindII, and BstEII. Of the 30 local strains studied, nine BglII, eight HindIII, six HindII, and five BstEII ribotype patterns were observed. In order to develop a typing scheme, we correlated the ribotype patterns obtained with each of the four enzymes for each strain. By this scheme, 13 ribotypes designated b to n were defined among the local strains. This study demonstrates that there is a diversity of ribotypes among H. ducreyi strains in our area, which emphasizes that there are many strains responsible for chancroid. This novel typing scheme provides a useful tool for further epidemiological studies of chancroid.

ASM Press eBooks, May 26, 2015

Emerging Infectious Diseases, Jul 1, 2011

Sexually Transmitted Diseases, Sep 1, 2018

Syphilis, caused by the bacterium Treponema pallidum, is on the rise in the United States particu... more Syphilis, caused by the bacterium Treponema pallidum, is on the rise in the United States particularly among men who have sex with men. The disease is complex with varied clinical manifestations and challenges remain in the laboratory diagnostic setting because T. pallidum is noncultivable and no single test can accurately diagnose all stages of the disease. There are missed opportunities for the use of direct detection tests in primary and secondary syphilis. The increasing use of different reverse sequence algorithms for serology testing without validation in populations with varying risks for syphilis makes the interpretation of test results difficult; this has led to concerns about diagnostic errors or overtreatment. On the other hand, the traditional algorithm may miss some early primary syphilis cases, which is of concern in high-risk populations. The potential utility of rapid syphilis serology tests in different settings or populations remains to be determined. The implementation of better tests and appropriate testing algorithms together with laboratory guidelines for test use in general will lead to better diagnostic options for syphilis.

The Journal of Infectious Diseases, Jun 1, 2001

A molecular-based subtyping system for Treponema pallidum was used during an investigation of inc... more A molecular-based subtyping system for Treponema pallidum was used during an investigation of increasing syphilis in Maricopa County, Arizona. Genital ulcer or whole blood specimens from patients with syphilis were assayed by a polymerase chain reaction (PCR) amplification of a T. pallidum DNA polymerase I gene. Positive specimens were typed on the basis of PCR amplification of 2 variable genes. In all, 41 (93%) of 44 of ulcer specimens and 4 (27%) of 15 blood specimens yielded typeable T. pallidum DNA. Twenty-four (53%) of 45 specimens were subtype 14f; other subtypes identified included 4f, 4i, 5f, 12a, 12f, 14a, 14d, 14e, and 14i. Only 2 specimens were from epidemiologically linked patients. This investigation demonstrates that multiple subtypes of T. pallidum can be found in an area with high syphilis morbidity, although 1 subtype (14f) was predominant. Four typeable specimens were from blood, a newly identified specimen source for subtyping. Syphilis remains an important infection because of its strong association with increased acquisition and transmission of human immunodeficiency virus (HIV) [1] and morbidity and mortality from congenital syphilis [2], as well as its substantial economic burden [3]. Although reported cases of syphilis are declining in the United States, cases are concentrated in a limited geographic range. In 1998, only 6993 cases of primary and secondary (P/S) syphilis were reported, compared with 150,000 in 1990. In all, 28 (0.9%) of 3115 US counties accounted for 50% of P/S syphilis cases [4]. Areas with epidemic syphilis or new outbreaks continue to challenge syphilis control and elimination efforts. These areas are now being assessed systematically, to understand the local variances in syphilis epidemiology and to prevent further transmission of disease [5]. Until recently, strains of Treponema pallidum subspecies pallidum (referred to here as T. pallidum), the causative agent of syphilis, could not be distinguished. However, insights from the

Sexually Transmitted Infections, Nov 10, 2006

To evaluate the molecular typing system for Treponema pallidum using cerebrospinal fluid (CSF) sp... more To evaluate the molecular typing system for Treponema pallidum using cerebrospinal fluid (CSF) specimens obtained from patients with neurosyphilis in Pretoria, South Africa. Methods: CSF specimens were collected from 32 men and 18 women with suspected late neurosyphilis. Typing of T pallidum involved PCR amplification and restriction analysis of the tpr E, G and J genes and determination of the number of 60 base pair tandem repeats within the arp gene by PCR amplification. Results: Of 13 typeable specimens, 4 strain types were identified: 2i, 3e, 14a and 17e. Subtype 14a was identified in 7 specimens (53.8%), subtype 3e in 4 specimens (30.7%) and subtypes 17e and 2i in 1 specimen (7.6%) each. Conclusions: This study shows that the typing system can be applied to specimens which may contain low numbers of spirochaetes such as CSF.

International Journal of Infectious Diseases, Apr 1, 2014

Results: The epidemic-curve showed a propagating pattern, with most cases being detected during o... more Results: The epidemic-curve showed a propagating pattern, with most cases being detected during or subsequent to ICU admission. Cases had longer mean hospital (27.8 days vs 11.9 days) and ICU stays (31.0 days vs 7.3 days) than controls. The crude in-hospital mortality of cases was significantly higher than controls (OR 13.02; 95% CI: 2.98-56.76). The final model showed co-morbid disease (Charlson Score) (AOR 1.68; 95% CI: 1.21-2.33); mechanical ventilation (AOR 1.35; 95% CI: 1.02-1.16) and receipt of piperacillin-tazobactam (AOR 1.33; 95% CI: 1.11-1.61) to be significant predictors for invasive disease. Invasive disease was strongly associated with mortality (AOR 9.62; 95% CI: 2.16-42.93). Conclusion: NDM-1 invasive disease is associated with significant mortality. Underlying co-morbidity, presence of invasive medical devices and exposure to antibiotics are important risk factors for NDM-1 invasive disease.

PLOS ONE, Sep 12, 2018

Yaws is a neglected tropical disease caused by the bacterium Treponema pallidum subspecies perten... more Yaws is a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue. The disease primarily affects children under 15 years of age living in low socioeconomic conditions in tropical areas. As a result of a renewed focus on the disease owing to a recent eradication effort initiated by the World Health Organization, we have evaluated a typing method, adapted from and based on the enhanced Centers for Disease Control and Prevention typing method for T. pallidum subsp. pallidum, for possible use in epidemiological studies. Thirty DNA samples from yaws cases in Vanuatu and Ghana, 11 DNA samples extracted from laboratory strains, and 3 published genomic sequences were fully typed by PCR/RFLP analysis of the tpr E, G, and J genes and by determining the number of 60-bp repeats within the arp gene. Subtyping was performed by sequencing a homonucleotide "G" tandem repeat immediately upstream of the rpsA gene and an 84-bp region of tp0548. A total of 22 complete strain types were identified; two strain types in clinical samples from Vanuatu (5q11/ak and 5q12/ak), nine strain types in clinical samples from Ghana (3q12/ah, 4r12/ah, 4q10/j, 4q11/ah, 4q12/ah, 4q12/v, 4q13/ah, 6q10/aj, and 9q10/ai), and twelve strain types in laboratory strains and published genomes (2q11/ae, 3r12/ad, 4q11/ ad, 4q12/ad, 4q12/ag, 4q12/v, 5r12/ad, 6r12/x, 6q11/af, 10q9/r, 10q12/r, and 12r12/w). The tpr RFLP patterns and arp repeat sizes were subsequently verified by sequencing analysis of the respective PCR amplicons. This study demonstrates that the typing method for subsp. pallidum can be applied to subsp. pertenue strains and should prove useful for molecular epidemiological studies on yaws.

Radiology Case Reports, May 1, 2019

Lymphogranuloma venereum is a sexually transmitted infection caused by serovars L1, L2, and L3 of... more Lymphogranuloma venereum is a sexually transmitted infection caused by serovars L1, L2, and L3 of Chlamydia trachomatis. We here report a case of Lymphogranuloma venereum, confirmed by PCR testing, which mimicked malignancy on CT imaging.

Sexually Transmitted Infections, Sep 1, 2015

Genome Announcements, Aug 25, 2016

Haemophilus ducreyi causes chancroid and has recently been shown to be a significant cause of cut... more Haemophilus ducreyi causes chancroid and has recently been shown to be a significant cause of cutaneous lesions in tropical or subtropical regions where yaws is endemic. Here, we report the draft genome assemblies for 11 cutaneous strains of Haemophilus ducreyi, isolated from children in Vanuatu and Ghana.

Sexually Transmitted Diseases, Nov 1, 2017

In September 2015, CDC was notified of a suspected outbreak investigation of lymphogranuloma vene... more In September 2015, CDC was notified of a suspected outbreak investigation of lymphogranuloma venereum (LGV) cases by the Michigan Department of Health and Human Services (MDHHS). CDC offered support with a laboratory-developed PCR test for LGV. This note describes the laboratory workflow and procedures used for the laboratory confirmation of LGV infection.

Journal of Clinical Microbiology, Aug 1, 2004

An immunochromatographic strip test, Xenostrip-Tv, was compared to wet mount and PCR for the diag... more An immunochromatographic strip test, Xenostrip-Tv, was compared to wet mount and PCR for the diagnosis of Trichomonas vaginalis infection in women. Of 428 specimens tested, 54 (12.6%) were positive by an "expanded gold standard," defined as either a positive wet mount and PCR test with primers TVK3 and TVK7 and/or a positive PCR test confirmed by a second PCR assay with primers TVA5-1 and TVA6; 26 (6%) were positive by wet mount, and 36 (8.4%) were positive by Xenostrip-Tv test. Since the Xenostrip-Tv test is rapid and easy to perform and proved to be more sensitive than wet mount, it should be considered as an alternative to wet mount for point-of-care diagnosis of trichomoniasis, especially in settings where microscopy is impractical.

The Journal of Infectious Diseases, Dec 22, 2017

Among men who have sex with men (MSM), those with a diagnosis of syphilis or other rectal sexuall... more Among men who have sex with men (MSM), those with a diagnosis of syphilis or other rectal sexually transmitted infections (STIs) are at a higher risk for human immunodeficiency virus acquisition, which is concerning given the large increase in recently reported syphilis cases in the United States. We have developed the first nonhuman primate model for rectally transmitted syphilis by exposing simian/human immunodeficiency virus-infected and naive rhesus macaques to Treponema pallidum in the rectum. All animals showed mucosal lesions, systemic dissemination, and seroconversion (treponemal antibodies). This model would be valuable for studying the manifestations of and interventions for T. pallidum infection, with and without human immunodeficiency virus coinfection.

Clinical Infectious Diseases, Jun 24, 2020

Direct detection methods for Treponema pallidum include dark-field microscopy (DFM), direct fluor... more Direct detection methods for Treponema pallidum include dark-field microscopy (DFM), direct fluorescence antibody (DFA) testing, immunohistochemistry (IHC), and nucleic acid amplification tests (NAATs). Here, we reviewed the relevant syphilis diagnostic literature to address 2 main questions with respect to T. pallidum direct detection techniques: "What are the performance characteristics for each direct detection test for T. pallidum and what are the optimal specimen types for each test?" and "What options are available for T. pallidum molecular epidemiology?" To answer these questions, we searched 5 electronic databases (OVID Medline, OVID Embase, CINAHL, Cochrane Library, and Scopus) from 1964 to 2017 using relevant search terms and identified 1928 articles, of which 37 met our inclusion criteria. DFM and DFA sensitivities ranged from 73% to 100% in cases of primary syphilis; and while sensitivity using silver stain histopathology for T. pallidum was generally low (0%-41%), higher performance characteristics were observed for T. pallidum-specific IHC (49-92%). Different genes have been targeted by T. pallidum-specific NAATs, with the majority of studies indicating that sensitivity is primarily dependent on the type of collected biological sample, with highest sensitivity observed in primary lesion exudate (75-95%). Given the rising incidence of syphilis, the development of direct, Food and Drug Administration-cleared T. pallidum NAATs should be considered an immediate priority.