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

Papers by Allan Pillay

Research paper thumbnail of A maintenance study of fishing vessel equipment using delay-time analysis

Journal of Quality in Maintenance Engineering, 2001

... A maintenance study of fishing vessel equipment using delay-time analysis. The Authors. A. Pi... more ... A maintenance study of fishing vessel equipment using delay-time analysis. The Authors. A. Pillay, Liverpool John Moores University, Liverpool, UK. J. Wang, Liverpool John Moores University, Liverpool, UK. AD Wall, Liverpool John Moores University, Liverpool, UK. ...

Research paper thumbnail of Comparison of culture media for the laboratory diagnosis of chancroid

Journal of Medical Microbiology, 1998

Seven different agar-based media were compared to determine the optimal set of culture media for ... more Seven different agar-based media were compared to determine the optimal set of culture media for primary isolation of Haemophilus ducreyi. Also, a new method for sampling genital ulcerswith a disposable sterile plastic loopand processing specimens that provides a standardised inoculum for culture of H. ducreyi on various media is described. A total of 202 patients with genital ulcer disease was enrolled in this study. A sterile swab or plastic loop was used to sample the base of the ulcers and ulcer material was suspended in sterile phosphate-buffered saline. A 100-p1 sample of this suspension was mixed with an equal volume of tryptic soy broth containing IsoVitaleX and centrifuged for 1 min. This suspension was used to inoculate the different media. Plates were incubated at 33°C in micro-aerophilic conditions and examined for growth of H. ducreyi after 48 h. Of the 202 specimens, 77 (38.1%) were culture positive for H. ducreyi. None of the agar bases supported the growth of all H. ducreyi strains. Based on this observation, we recommend the universal use of Mueller-Hinton agar base supplemented with chocolate horse blood and IsovitaleX (MH-HBC) and Columbia agar base supplemented with bovine haemoglobin, activated charcoal, fetal calf serum and IsovitaleX (C-HgCh) to enable comparison of prevalence figures for chancroid. In addition, the novel sampling technique described in this study eliminates sampling bias normally associated with genital ulcer specimens.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum Subspecies pallidum

Sexually Transmitted Diseases, 1998

Research paper thumbnail of Molecular Epidemiology of Syphilis—San Francisco, 2004–2007

Sexually Transmitted Diseases, 2010

We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum... more We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum specimens obtained from patients examined at the SF municipal sexually transmitted diseases clinic during 2004 -2007. Of 69 specimens, 52 (75%) were subtype 14d9. Single subtype predominance might reflect a closely linked sexual network in SF.

Research paper thumbnail of Evaluation of Xenostrip-Tv, a Rapid Diagnostic Test for Trichomonas vaginalis Infection

Journal of Clinical Microbiology, 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.

Research paper thumbnail of Comparison of a TaqMan-based real-time polymerase chain reaction with conventional tests for the detection of Trichomonas vaginalis

Sexually Transmitted Infections, 2007

Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional ... more Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional PCR, culture, and wet-mount microscopy for the diagnosis of trichomoniasis in women. Methods: Vaginal swabs from 119 women were tested for Trichomonas vaginalis by wet mount and culture. Paired vaginal lavage and urine specimens were tested by conventional and real-time PCR. Results: Using an expanded ''gold standard'', defined as a positive culture result using vaginal swabs and/or a positive PCR test using TVK3/7 primers, the overall prevalence of T vaginalis in the study population was 65.5% (78/119). The detection rate of T vaginalis was 65.5% (78/119) and 36.9% (44/119) by conventional PCR using vaginal washings and urine specimens, respectively; 68.9% (82/119) by real-time PCR using vaginal washings and 61.3% (73/119) by real-time PCR using urine specimens. The sensitivities of conventional PCR using vaginal washings and urine and real-time PCR using vaginal washings and urine, compared with the gold standard were 100%, 56.4%, 100% and 76.7%, and the specificities of these tests were 100%, 97.6%, 82.9% and 97%, respectively. Conclusions: The real-time PCR test proved to be significantly more sensitive than culture and wet-mount microscopy, although its specificity was slightly lower than these tests. In addition, it was more sensitive, rapid and less time consuming than conventional PCR for the detection of T vaginalis.

Research paper thumbnail of Molecular typing of Treponema pallidum strains from patients with neurosyphilis in Pretoria, South Africa

Sexually Transmitted Infections, 2006

strains Treponema pallidum Molecular typing of http://sti.bmj.com/cgi/content/full/83/3/189

Research paper thumbnail of Molecular Typing of Treponema pallidum in South Africa: Cross-Sectional Studies

Journal of Clinical Microbiology, 2002

We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate... more We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate between strains obtained from male patients with primary syphilis in South Africa. Of 201 T. pallidum-positive specimens, 161 were typeable, revealing 35 subtypes. The unique subtypes identified in Durban, Cape Town, and Carletonville and the total number of subtypes suggested that the strain population was very diverse and varied geographically.

Research paper thumbnail of Amplification of the DNA polymerase I gene of Treponema pallidum from whole blood of persons with syphilis

Diagnostic Microbiology and Infectious Disease, 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.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum in an Arizona County with Increasing Syphilis Morbidity: Use of Specimens from Ulcers and Blood

Journal of Infectious Diseases, 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.

Research paper thumbnail of Comparison of culture media for the laboratory diagnosis of chancroid

Journal of Medical Microbiology, 1998

Seven different agar-based media were compared to determine the optimal set of culture media for ... more Seven different agar-based media were compared to determine the optimal set of culture media for primary isolation of Haemophilus ducreyi. Also, a new method for sampling genital ulcerswith a disposable sterile plastic loopand processing specimens that provides a standardised inoculum for culture of H. ducreyi on various media is described. A total of 202 patients with genital ulcer disease was enrolled in this study. A sterile swab or plastic loop was used to sample the base of the ulcers and ulcer material was suspended in sterile phosphate-buffered saline. A 100-p1 sample of this suspension was mixed with an equal volume of tryptic soy broth containing IsoVitaleX and centrifuged for 1 min. This suspension was used to inoculate the different media. Plates were incubated at 33°C in micro-aerophilic conditions and examined for growth of H. ducreyi after 48 h. Of the 202 specimens, 77 (38.1%) were culture positive for H. ducreyi. None of the agar bases supported the growth of all H. ducreyi strains. Based on this observation, we recommend the universal use of Mueller-Hinton agar base supplemented with chocolate horse blood and IsovitaleX (MH-HBC) and Columbia agar base supplemented with bovine haemoglobin, activated charcoal, fetal calf serum and IsovitaleX (C-HgCh) to enable comparison of prevalence figures for chancroid. In addition, the novel sampling technique described in this study eliminates sampling bias normally associated with genital ulcer specimens.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum Subspecies pallidum

Sexually Transmitted Diseases, 1998

Research paper thumbnail of Molecular Epidemiology of Syphilis—San Francisco, 2004–2007

Sexually Transmitted Diseases, 2010

We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum... more We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum specimens obtained from patients examined at the SF municipal sexually transmitted diseases clinic during 2004 -2007. Of 69 specimens, 52 (75%) were subtype 14d9. Single subtype predominance might reflect a closely linked sexual network in SF.

Research paper thumbnail of Evaluation of Xenostrip-Tv, a Rapid Diagnostic Test for Trichomonas vaginalis Infection

Journal of Clinical Microbiology, 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.

Research paper thumbnail of Comparison of a TaqMan-based real-time polymerase chain reaction with conventional tests for the detection of Trichomonas vaginalis

Sexually Transmitted Infections, 2007

Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional ... more Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional PCR, culture, and wet-mount microscopy for the diagnosis of trichomoniasis in women. Methods: Vaginal swabs from 119 women were tested for Trichomonas vaginalis by wet mount and culture. Paired vaginal lavage and urine specimens were tested by conventional and real-time PCR. Results: Using an expanded ''gold standard'', defined as a positive culture result using vaginal swabs and/or a positive PCR test using TVK3/7 primers, the overall prevalence of T vaginalis in the study population was 65.5% (78/119). The detection rate of T vaginalis was 65.5% (78/119) and 36.9% (44/119) by conventional PCR using vaginal washings and urine specimens, respectively; 68.9% (82/119) by real-time PCR using vaginal washings and 61.3% (73/119) by real-time PCR using urine specimens. The sensitivities of conventional PCR using vaginal washings and urine and real-time PCR using vaginal washings and urine, compared with the gold standard were 100%, 56.4%, 100% and 76.7%, and the specificities of these tests were 100%, 97.6%, 82.9% and 97%, respectively. Conclusions: The real-time PCR test proved to be significantly more sensitive than culture and wet-mount microscopy, although its specificity was slightly lower than these tests. In addition, it was more sensitive, rapid and less time consuming than conventional PCR for the detection of T vaginalis.

Research paper thumbnail of Molecular typing of Treponema pallidum strains from patients with neurosyphilis in Pretoria, South Africa

Sexually Transmitted Infections, 2006

strains Treponema pallidum Molecular typing of http://sti.bmj.com/cgi/content/full/83/3/189

Research paper thumbnail of Molecular Typing of Treponema pallidum in South Africa: Cross-Sectional Studies

Journal of Clinical Microbiology, 2002

We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate... more We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate between strains obtained from male patients with primary syphilis in South Africa. Of 201 T. pallidum-positive specimens, 161 were typeable, revealing 35 subtypes. The unique subtypes identified in Durban, Cape Town, and Carletonville and the total number of subtypes suggested that the strain population was very diverse and varied geographically.

Research paper thumbnail of Amplification of the DNA polymerase I gene of Treponema pallidum from whole blood of persons with syphilis

Diagnostic Microbiology and Infectious Disease, 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.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum in an Arizona County with Increasing Syphilis Morbidity: Use of Specimens from Ulcers and Blood

Journal of Infectious Diseases, 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.

Research paper thumbnail of A maintenance study of fishing vessel equipment using delay-time analysis

Journal of Quality in Maintenance Engineering, 2001

... A maintenance study of fishing vessel equipment using delay-time analysis. The Authors. A. Pi... more ... A maintenance study of fishing vessel equipment using delay-time analysis. The Authors. A. Pillay, Liverpool John Moores University, Liverpool, UK. J. Wang, Liverpool John Moores University, Liverpool, UK. AD Wall, Liverpool John Moores University, Liverpool, UK. ...

Research paper thumbnail of Comparison of culture media for the laboratory diagnosis of chancroid

Journal of Medical Microbiology, 1998

Seven different agar-based media were compared to determine the optimal set of culture media for ... more Seven different agar-based media were compared to determine the optimal set of culture media for primary isolation of Haemophilus ducreyi. Also, a new method for sampling genital ulcerswith a disposable sterile plastic loopand processing specimens that provides a standardised inoculum for culture of H. ducreyi on various media is described. A total of 202 patients with genital ulcer disease was enrolled in this study. A sterile swab or plastic loop was used to sample the base of the ulcers and ulcer material was suspended in sterile phosphate-buffered saline. A 100-p1 sample of this suspension was mixed with an equal volume of tryptic soy broth containing IsoVitaleX and centrifuged for 1 min. This suspension was used to inoculate the different media. Plates were incubated at 33°C in micro-aerophilic conditions and examined for growth of H. ducreyi after 48 h. Of the 202 specimens, 77 (38.1%) were culture positive for H. ducreyi. None of the agar bases supported the growth of all H. ducreyi strains. Based on this observation, we recommend the universal use of Mueller-Hinton agar base supplemented with chocolate horse blood and IsovitaleX (MH-HBC) and Columbia agar base supplemented with bovine haemoglobin, activated charcoal, fetal calf serum and IsovitaleX (C-HgCh) to enable comparison of prevalence figures for chancroid. In addition, the novel sampling technique described in this study eliminates sampling bias normally associated with genital ulcer specimens.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum Subspecies pallidum

Sexually Transmitted Diseases, 1998

Research paper thumbnail of Molecular Epidemiology of Syphilis—San Francisco, 2004–2007

Sexually Transmitted Diseases, 2010

We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum... more We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum specimens obtained from patients examined at the SF municipal sexually transmitted diseases clinic during 2004 -2007. Of 69 specimens, 52 (75%) were subtype 14d9. Single subtype predominance might reflect a closely linked sexual network in SF.

Research paper thumbnail of Evaluation of Xenostrip-Tv, a Rapid Diagnostic Test for Trichomonas vaginalis Infection

Journal of Clinical Microbiology, 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.

Research paper thumbnail of Comparison of a TaqMan-based real-time polymerase chain reaction with conventional tests for the detection of Trichomonas vaginalis

Sexually Transmitted Infections, 2007

Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional ... more Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional PCR, culture, and wet-mount microscopy for the diagnosis of trichomoniasis in women. Methods: Vaginal swabs from 119 women were tested for Trichomonas vaginalis by wet mount and culture. Paired vaginal lavage and urine specimens were tested by conventional and real-time PCR. Results: Using an expanded ''gold standard'', defined as a positive culture result using vaginal swabs and/or a positive PCR test using TVK3/7 primers, the overall prevalence of T vaginalis in the study population was 65.5% (78/119). The detection rate of T vaginalis was 65.5% (78/119) and 36.9% (44/119) by conventional PCR using vaginal washings and urine specimens, respectively; 68.9% (82/119) by real-time PCR using vaginal washings and 61.3% (73/119) by real-time PCR using urine specimens. The sensitivities of conventional PCR using vaginal washings and urine and real-time PCR using vaginal washings and urine, compared with the gold standard were 100%, 56.4%, 100% and 76.7%, and the specificities of these tests were 100%, 97.6%, 82.9% and 97%, respectively. Conclusions: The real-time PCR test proved to be significantly more sensitive than culture and wet-mount microscopy, although its specificity was slightly lower than these tests. In addition, it was more sensitive, rapid and less time consuming than conventional PCR for the detection of T vaginalis.

Research paper thumbnail of Molecular typing of Treponema pallidum strains from patients with neurosyphilis in Pretoria, South Africa

Sexually Transmitted Infections, 2006

strains Treponema pallidum Molecular typing of http://sti.bmj.com/cgi/content/full/83/3/189

Research paper thumbnail of Molecular Typing of Treponema pallidum in South Africa: Cross-Sectional Studies

Journal of Clinical Microbiology, 2002

We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate... more We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate between strains obtained from male patients with primary syphilis in South Africa. Of 201 T. pallidum-positive specimens, 161 were typeable, revealing 35 subtypes. The unique subtypes identified in Durban, Cape Town, and Carletonville and the total number of subtypes suggested that the strain population was very diverse and varied geographically.

Research paper thumbnail of Amplification of the DNA polymerase I gene of Treponema pallidum from whole blood of persons with syphilis

Diagnostic Microbiology and Infectious Disease, 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.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum in an Arizona County with Increasing Syphilis Morbidity: Use of Specimens from Ulcers and Blood

Journal of Infectious Diseases, 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.

Research paper thumbnail of Comparison of culture media for the laboratory diagnosis of chancroid

Journal of Medical Microbiology, 1998

Seven different agar-based media were compared to determine the optimal set of culture media for ... more Seven different agar-based media were compared to determine the optimal set of culture media for primary isolation of Haemophilus ducreyi. Also, a new method for sampling genital ulcerswith a disposable sterile plastic loopand processing specimens that provides a standardised inoculum for culture of H. ducreyi on various media is described. A total of 202 patients with genital ulcer disease was enrolled in this study. A sterile swab or plastic loop was used to sample the base of the ulcers and ulcer material was suspended in sterile phosphate-buffered saline. A 100-p1 sample of this suspension was mixed with an equal volume of tryptic soy broth containing IsoVitaleX and centrifuged for 1 min. This suspension was used to inoculate the different media. Plates were incubated at 33°C in micro-aerophilic conditions and examined for growth of H. ducreyi after 48 h. Of the 202 specimens, 77 (38.1%) were culture positive for H. ducreyi. None of the agar bases supported the growth of all H. ducreyi strains. Based on this observation, we recommend the universal use of Mueller-Hinton agar base supplemented with chocolate horse blood and IsovitaleX (MH-HBC) and Columbia agar base supplemented with bovine haemoglobin, activated charcoal, fetal calf serum and IsovitaleX (C-HgCh) to enable comparison of prevalence figures for chancroid. In addition, the novel sampling technique described in this study eliminates sampling bias normally associated with genital ulcer specimens.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum Subspecies pallidum

Sexually Transmitted Diseases, 1998

Research paper thumbnail of Molecular Epidemiology of Syphilis—San Francisco, 2004–2007

Sexually Transmitted Diseases, 2010

We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum... more We describe the molecular epidemiology of syphilis in San Francisco (SF) using Treponema pallidum specimens obtained from patients examined at the SF municipal sexually transmitted diseases clinic during 2004 -2007. Of 69 specimens, 52 (75%) were subtype 14d9. Single subtype predominance might reflect a closely linked sexual network in SF.

Research paper thumbnail of Evaluation of Xenostrip-Tv, a Rapid Diagnostic Test for Trichomonas vaginalis Infection

Journal of Clinical Microbiology, 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.

Research paper thumbnail of Comparison of a TaqMan-based real-time polymerase chain reaction with conventional tests for the detection of Trichomonas vaginalis

Sexually Transmitted Infections, 2007

Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional ... more Objective: To compare a TaqMan-based real-time polymerase chain reaction (PCR) with conventional PCR, culture, and wet-mount microscopy for the diagnosis of trichomoniasis in women. Methods: Vaginal swabs from 119 women were tested for Trichomonas vaginalis by wet mount and culture. Paired vaginal lavage and urine specimens were tested by conventional and real-time PCR. Results: Using an expanded ''gold standard'', defined as a positive culture result using vaginal swabs and/or a positive PCR test using TVK3/7 primers, the overall prevalence of T vaginalis in the study population was 65.5% (78/119). The detection rate of T vaginalis was 65.5% (78/119) and 36.9% (44/119) by conventional PCR using vaginal washings and urine specimens, respectively; 68.9% (82/119) by real-time PCR using vaginal washings and 61.3% (73/119) by real-time PCR using urine specimens. The sensitivities of conventional PCR using vaginal washings and urine and real-time PCR using vaginal washings and urine, compared with the gold standard were 100%, 56.4%, 100% and 76.7%, and the specificities of these tests were 100%, 97.6%, 82.9% and 97%, respectively. Conclusions: The real-time PCR test proved to be significantly more sensitive than culture and wet-mount microscopy, although its specificity was slightly lower than these tests. In addition, it was more sensitive, rapid and less time consuming than conventional PCR for the detection of T vaginalis.

Research paper thumbnail of Molecular typing of Treponema pallidum strains from patients with neurosyphilis in Pretoria, South Africa

Sexually Transmitted Infections, 2006

strains Treponema pallidum Molecular typing of http://sti.bmj.com/cgi/content/full/83/3/189

Research paper thumbnail of Molecular Typing of Treponema pallidum in South Africa: Cross-Sectional Studies

Journal of Clinical Microbiology, 2002

We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate... more We evaluated a molecular subtyping system for Treponema pallidum for its ability to differentiate between strains obtained from male patients with primary syphilis in South Africa. Of 201 T. pallidum-positive specimens, 161 were typeable, revealing 35 subtypes. The unique subtypes identified in Durban, Cape Town, and Carletonville and the total number of subtypes suggested that the strain population was very diverse and varied geographically.

Research paper thumbnail of Amplification of the DNA polymerase I gene of Treponema pallidum from whole blood of persons with syphilis

Diagnostic Microbiology and Infectious Disease, 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.

Research paper thumbnail of Molecular Subtyping of Treponema pallidum in an Arizona County with Increasing Syphilis Morbidity: Use of Specimens from Ulcers and Blood

Journal of Infectious Diseases, 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.