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Biomedical subjects

S N Tabrizi

Publications and source records attributed to S N Tabrizi.

At least 19 recordsLinked to original sources
PubMed2006

The association of Atopobium vaginae and Gardnerella vaginalis with bacterial vaginosis and recurrence after oral metronidazole therapy.

BACKGROUND: We investigated associations between Atopobium vaginae and bacterial vaginosis (BV) and the role that A. vaginae plays in recurrent BV after oral metronidazole therapy. METHODS: Women with abnormal vaginal discharge or odor were enrolled in a cross-sectional study (n=358); the proportion of those infected with Gardnerella vaginalis and A. vaginae was determined by polymerase chain reaction. Women with BV (Nugent score [NS] 7-10 or 4-6 with > or =3 Amsel criteria; n=139) were treated with oral metronidazole (400 mg twice a day for 7 days) and examined at 1, 3, 6, and 12 months or until they reached an NS of 7-10 and recurrence of A. vaginae and G. vaginalis infection was established. RESULTS: A. vaginae and G. vaginalis were highly sensitive for BV--96% (95% confidence interval [CI], 91%-98%) and 99% (95% CI, 97%-100%), respectively. However, A. vaginalis was more specific for BV (77% [95% CI, 71%-82%]) than was G. vaginalis (35% [95% CI, 29%-42%]). G. vaginalis was detected in 100% and A. vaginae in 75% of women with recurrent BV; higher organism loads were present in women with recurrent BV. A. vaginae was rarely detected without G. vaginalis, and women in whom both organisms were detected had higher rates of recurrent BV (83%) than women infected with G. vaginalis only (38%) (P<.001). CONCLUSIONS: Infection with A. vaginae is more specific for BV than infection with G. vaginalis. The higher recurrence rates in women in whom both A. vaginae and G. vaginalis were detected suggest that A. vaginae makes a significant contribution to BV. However, its etiological role remains unclear.

Actinobacteria↗
PubMed2006

Re-infection of Neisseria gonorrhoeae and Chlamydia trachomatis infections among men who have sex with men.

Our aim was to determine the incidence of re-infection of men who have sex with men (MSM) for rectal Neisseria gonorrhoeae (RNg) and rectal Chlamydia trachomatis (RCt) infection. The medical records of 126 MSM diagnosed with RNg or RCt infections at Melbourne Sexual Health Centre were reviewed. A total of 68 of the 126 (54%) MSM were re-tested. Among the HIV-positive MSM, 17 (81%) of 21 were re-tested and eight were positive (47%, 95% confidence interval [CI] 23-72%). Among the 51 (49%) of 105 of the HIV-negative or unknown MSM re-tested, 13 (25%, 14-40) were positive. Of the 21 infections identified, five cases were symptomatic. The incidence of rectal infections among MSM is high and prior RNg or RCt should be included as a risk factor for frequent screening.

Adult↗
PubMed2005

Screening injecting drug users for sexually transmitted infections and blood borne viruses using street outreach and self collected sampling.

BACKGROUND: Injecting drug users (IDUs) are a marginalised population, who infrequently access health services for screening for sexually transmitted infections (STIs) and blood borne viruses (BBVs), and are at high risk of these infections. OBJECTIVES: To use street outreach and self collection of samples for STI screening, to establish the prevalence of BBVs and STIs, and to identify risk behaviours among a group of culturally diverse street based IDUs. METHODS: This was a cross sectional study of 314 IDUs in the central business district of Melbourne, Australia, conducted over 3 years (1999-2002). We used street outreach as the recruitment strategy with staff "on foot" in injecting and dealing locations, as well as self collected genital sampling to increase acceptance of screening for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis by polymerase chain reaction (PCR). Individuals were screened for hepatitis A, B, and C, syphilis and HIV, and given the option of a self collected or clinician collected blood sample to increase acceptance of screening for BBVs. RESULTS: Street outreach was highly effective and self directed STI sampling was more acceptable than practitioner directed sampling (76% versus 9% acceptance, p<0.001). There was a high prevalence of hepatitis C (74%, 95% CI 69 to 79), STIs (8% (5 to 13)), and chlamydia (6% (3 to 10)), and past exposure to hepatitis A and B was common. High rates of recent sharing of injecting equipment, unprotected sex and casual sexual partners, together with low levels of awareness of current hepatitis C infection were identified. CONCLUSION: Street outreach and self collected genital samples facilitate screening for STIs and BBVs in IDUs and revealed a high prevalence of infections and risk behaviours.

Adolescent↗
PubMed2005

A cluster of culture positive gonococcal infections but with false negative cppB gene based PCR.

OBJECTIVES: To describe the prevalence and characteristics of isolates of Neisseria gonorrhoeae grown from urine samples that produced negative results with nucleic acid amplification assays (NAA) targeting the cppB gene. METHODS: An initial cluster of culture positive, but cppB gene based NAA negative, gonococcal infections was recognised. Urine samples and suspensions of gonococci isolated over 9 months in the Northern Territory of Australia were examined using cppB gene based and other non-cppB gene based NAA. The gonococcal isolates were phenotyped by determining the auxotype/serovar (A/S) class and genotyped by pulsed field gel electrophoresis (PFGE). RESULTS: 14 (9.8%) of 143 gonococci isolated were of A/S class Pro(-/)Brpyut, indistinguishable on PFGE and negative in cppB gene based, but not other, NAA. CONCLUSIONS: This cluster represents a temporal and geographic expansion of a gonococcal subtype lacking the cppB gene with consequent loss of sensitivity of NAA dependent on amplification of this target. Gonococci lacking the cppB gene have in the past been more commonly associated with the PAU-/PCU- auxotype, a gonococcal subtype hitherto infrequently encountered in Australia. NAA based on the cppB gene as a target may produce false positive as well as false negative NAA. This suggests that unless there is continuing comparison with culture to show their utility, cppB gene based NAA should be regarded as suboptimal for use either as a diagnostic or supplemental assay for diagnosis of gonorrhoea, and NAA with alternative amplification targets should be substituted.

Bacterial Outer Membrane Proteins↗
PubMed2005

Comparison of conventional testing to polymerase chain reaction in detection of Trichomonas vaginalis in indigenous women living in remote areas.

There are high rates of Trichomonas vaginalis in remote areas of Central Australia. Conventional tests for T. vaginalis have low sensitivity in this setting. Aims of the study were to estimate the prevalence of T. vaginalis, to assess the presence of clinical signs and symptoms, to compare a T. vaginalis polymerase chain reaction (PCR) test with conventional methods of diagnosis, and to compare the PCR from different samples, including self-collected swabs (SCS). Of 205 women recruited, the prevalence of T. vaginalis was 24%. The prevalence of T. vaginalis was higher in women under 25 years (33%), compared with those who were 25-34 years (26%) and those over 35 years (15%, P < 0.05). The sensitivity of T. vaginalis PCR detection from SCS (94%) was not statistically different from a practitioner-collected HVS (96%), but was superior to urine PCR (74%) and conventional methods. After multivariate analysis, those women with high pH were almost three times more likely to be positive for T. vaginalis (odds ratio = 2.71 with 95% confidence interval 1.06-6.93, P = 0.037). Superior assays such as PCR should be a diagnostic option to adequately screen and treat women with T. vaginalis, in order to reduce complications, including the increased risk of HIV transmission.

Adult↗
PubMed2004

Validation of roche COBAS Amplicor assay for detection of Chlamydia trachomatis in rectal and pharyngeal specimens by an omp1 PCR assay.

Screening guidelines for men who have sex with men (MSM) recommend testing of extragenital sites (pharyngeal and rectal) for gonorrhoea and chlamydia. Testing of specimens from these sites is not validated by most commercial nucleic amplification tests, such as the COBAS Amplicor assay. To investigate the utility of the COBAS Amplicor assay for detection of Chlamydia trachomatis in extragenital specimens, this study developed and evaluated confirmatory tests using the omp1 gene as an alternative target for amplification by PCR. Of anal and throat swabs collected from men in male-only saunas, 52 swabs that tested C. trachomatis positive by COBAS Amplicor and 30 swabs that tested as negative were included for confirmatory omp1 PCR testing. A total of 49 (94%) COBAS Amplicor-positive samples were confirmed by the omp1 PCR. A substantial proportion of specimens were confirmed by using a nested omp1 PCR (27%). Not confirmed by any omp1 PCR were three anal swabs (6%). It is most probable that these samples contained lower bacterial levels that were near or below the detection level of the omp1 PCR assays. The findings of this study support the confident reporting of C. trachomatis detected by COBAS Amplicor in extragenital specimens and support the utility of this assay as a screening test for MSM.

Chlamydia trachomatis↗
PubMed2004

Evaluation of real time polymerase chain reaction assays for confirmation of Neisseria gonorrhoeae in clinical samples tested positive in the Roche Cobas Amplicor assay.

OBJECTIVE: Development of a rapid, sensitive, and accurate assay for confirmation of Neisseria gonorrhoeae in clinical samples. METHOD: Two real time polymerase chain reaction (PCR) assays, developed on the LightCycler for amplification of the N gonorrhoeae cppB gene, were utilised for confirmation of this bacterial pathogen in samples positive by the Roche Cobas Amplicor assay. Performance characteristics of the two assays were compared with other commercial nucleic acid amplification assays, including the Abbott LCx and Roche 16S rRNA tests. RESULTS: All related Neisseria as well as other bacterial species tested negative by both cppB gene based assays, whereas 120 N gonorrhoeae clinical isolates from various geographical regions gave in positive results. Both assays had a sensitivity of one copy per reaction. 122 clinical samples positive and another 50 samples negative for N gonorrhoeae by Roche Cobas Amplicor were selected from a specimen pool of more than 3000 women tested previously. Overall, 73 of 122 (59.8%) samples were confirmed as positive. The two real time assays had sensitivities of 99% and 100% and specificities of 98% and 100%, respectively. The 16S and LCx assays produced similar results to the real time assays, indicating a similar sensitivity to and specificity of both real time assays. CONCLUSION: The data from this study highlight the need to confirm N gonorrhoeae positive Cobas Amplicor PCR results as an important part of the testing algorithm of all diagnostic laboratories utilising this assay.

DNA, Bacterial↗
PubMed2003

Adolescence and other risk factors for Chlamydia trachomatis genitourinary infection in women in Melbourne, Australia.

OBJECTIVE: To establish the prevalence of and risk factors for Chlamydia trachomatis infection to determine the role of universal versus targeted testing. METHODS: A prospective study of 1107 women attending two sexual and reproductive health clinics in Melbourne, Australia, was carried out. A questionnaire was used to establish risk factors. Urine samples were tested for C. trachomatis by PCR. The main outcome measures were prevalence of and risk factors for C. trachomatis infection. RESULTS: Of 1107 recruitable women, 851 (76.9%) consented and were successfully tested. C. trachomatis was detected in 18 (4.8% (95% CI 2.9 to 7.5)) of 373 women in the inner city and eight (1.7% (95% CI (0.7 to 3.3)) of 478 women in the suburban clinic. Of women under 25 years, 17 (6.2% (95% CI 3.7 to 9.8)) of 273 in the inner city in contrast with three (1.7% (95% CI 0.4 to 5.0)) of 174 in the suburban clinic were infected. In the inner city clinic, age under 25 years (OR 5.4 (95% CI 0.7 to 41.5)), vaginal discharge (OR 4.1 (95% CI 1.5 to 11.1)), and recent change of sexual partner (OR 4.6 (95% CI 1.6 to 12.9)) were associated with C. trachomatis. In contrast, in the suburban clinic, only vaginal discharge (OR 3.5 (95% CI 0.9 to 14.3)) and recent change of sexual partner (OR 3.4 (95% CI 0.8 to 15.7)) were identified as risk factors. Multivariate analysis showed that recent change of partner (OR 4.5 (95% CI 1.5 to 13.8)) was the most strongly associated independent risk factor for infection in the inner city clinic. CONCLUSION: The high prevalence of C. trachomatis indicates that universal testing should be undertaken in the inner city clinic. Young age may not be a risk factor for C. trachomatis in more affluent populations with lower prevalence rates. No risk factors were identified with sufficient sensitivity and specificity to be useful for targeted testing. Prevalence and identifiable risk factors for C. trachomatis are not transferable between populations, even in the same city.

Adolescent↗
PubMed2002

Genetic aberrations detected by comparative genomic hybridisation in vulvar cancers.

Squamous cell carcinoma of the vulva is a disease of significant clinical importance, which arises in the presence or absence of human papillomavirus. We used comparative genomic hybridisation to document non-random chromosomal gains and losses within human papillomavirus positive and negative vulvar cancers. Gain of 3q was significantly more common in human papillomavirus-positive cancers compared to human papillomavirus-negative cancers. The smallest area of gain was 3q22-25, a chromosome region which is frequently gained in other human papillomavirus-related cancers. Chromosome 8q was more commonly gained in human papillomavirus-negative compared to human papillomavirus-positive cancers. 8q21 was the smallest region of gain, which has been identified in other, non-human papillomavirus-related cancers. Chromosome arms 3p and 11q were lost in both categories of vulvar cancer. This study has demonstrated chromosome locations important in the development of vulvar squamous cell carcinoma. Additionally, taken together with previous studies of human papillomavirus-positive cancers of other anogenital sites, the data indicate that one or more oncogenes important in the development and progression of human papillomavirus-induced carcinomas are located on 3q. The different genetic changes seen in human papillomavirus-positive and negative vulvar squamous cell carcinomas support the clinicopathological data indicating that these are different cancer types.

Carcinoma, Squamous Cell↗
PubMed2001

Seroprevalence of herpes simplex virus types 1 and 2 in HIV-infected and uninfected homosexual men in a primary care setting.

BACKGROUND: Genital herpes is usually caused by herpes simplex virus type 2 (HSV-2), with infections often being unrecognised by patients and/or clinicians. HSV-2 infections may be a risk factor for the transmission of human immunodeficiency virus (HIV) infection. Reliable tests for type-specific HSV antibodies are now readily available. OBJECTIVES: To determine the seroprevalence of HSV-1 and -2 in HIV-seronegative gay men in a primary care setting in Melbourne, Australia, and to compare it with the rate in HIV-infected gay men. To assess the utility in a clinical setting of a type-specific HSV enzyme linked immunosorbent assay (ELISA) as compared with western blot. STUDY DESIGN: We recruited a total of 300 HIV-seronegative homosexual men attending for HIV antibody testing, and HIV-infected men attending for CD4 lymphocyte count and viral load estimation. The subjects completed a questionnaire, and sera were sent for total IgG HSV testing and testing by Gull type-specific HSV ELISA assay. Selected serum samples were retested by western blotting and the results analysed. RESULTS: In total, 168 HIV-antibody negative men and 132 HIV-antibody positive men were recruited. Of all subjects, 73.3% had HSV-1 antibodies. This proportion did not differ between HIV-seronegative and seropositive men (P=0.48). About twenty percent of HIV-seronegative men and 61% of HIV-seropositive men had antibodies to HSV-2 (P<0.0001); 75.6% of HIV-seronegative men with antibodies to HSV-2 gave no history of genital herpes, as did 66.7% of HIV-seropositive men. Overall, in using the type-specific ELISA (Gull) assay, false negative, false positive or equivocal results were obtained in 33/300 (11%) of samples tested compared with western blot. CONCLUSIONS: High rates of HSV-2 infection were found in homosexual males, with the rate for HIV-seropositive men being over twice that for HIV uninfected men. Most subjects were not aware of their infection with HSV-2. HIV-infected individuals were also older and had higher numbers of sexual partners, but we were unable to unambiguously establish that these variables contributed to the difference in HSV-2 seroprevalence rates. The Gull type-specific assay for HSV antibodies has significant problems with sensitivity and specificity at a discrepancy rate of 11%. Caution is advised in using this type-specific commercial assay for clinical purposes.

Adult↗
PubMed2001

Prevalence of sexually transmitted infections (Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis and human papillomavirus) in female attendees of a sexually transmitted diseases clinic in Ulaanbaatar, Mongolia.

BACKGROUND: Epidemiological data suggest that the prevalence of syphilis, gonorrhea and trichomoniasis has increased in both urban and rural areas of Mongolia. These data are primarily substantiated by notifications of cases of clinically apparent disease in both rural and urban areas, plus laboratory diagnoses from the AIDS/STD Reference Center, Ulaanbaatar. In the past 5 years, however, there has been a marked decline in the total number of patients being screened for sexually transmitted infections (STIs). An assessment of true prevalence of STIs in a female population attending an urban sexually transmitted diseases (STD) clinic was therefore commenced. METHODS: Consecutive women attending an STD clinic in Ulaanbaatar had genital samples collected by the insertion and immediate removal of a tampon, which was then tested for the presence of Neisseria gonorrhoeae, Chlamydia trachomatis, human papillomavirus (HPV) and Trichomonas vaginalis, using polymerase chain reaction (PCR) amplification. RESULTS: A total of 110 women were studied (mean age 26.7 years). Overall, 58 (53%) patients had one or more pathogens identified; 43 (39%) had a single pathogen, while 15 (14%) had mixed pathogens. C. trachomatis was found in 15 (14%), N. gonorrhoeae in 12 (11%), T. vaginalis in nine (8%) and HPV in 39 (36%). Among the 39 HPV-positive patients, oncogenicgenotypes (16, 18, 31, 33, 35, 39, 45, 51, 52) were found in 17(44%) patients. CONCLUSIONS: Sexually transmitted infections as defined by PCR were common, and found in 53% of female attendees of an urban STD clinic in Mongolia. As infections with conventional STIs increase the risk of human immunodeficiency virus (HIV) transmission, it is imperative that strategies be introduced to reduce the prevalence of STIs. Furthermore, detection of oncogenic HPV was common, indicating that it is vital that a strategy to reduce cervical cancer such as a pre-cancer cervical cytology screening program also be introduced.

Adult↗
PubMed2000

Progressive genetic aberrations detected by comparative genomic hybridization in squamous cell cervical cancer.

Genetic changes orchestrated by human papillomaviruses are the most important known factors in carcinogenesis of the uterine cervix. However, it is clear that additional genetic events are necessary for tumour progression. We have used comparative genomic hybridization to document non-random chromosomal gains and losses within a subset of 37 cervical carcinomas matched for clinical stage Ib, but with different lymph node status. There were significantly more chromosomal changes in the primary tumours when the lymph nodes were positive for metastases. The most frequent copy number alterations were loss of 3p, 11q, 6q and 10q and gain of 3q. The smallest areas of loss and gain on chromosome 3 were 3p14-22 and 3q24-26. The study identifies progressive DNA copy number changes associated with early-stage invasive cervical cancers with and without lymph node metastases, a factor of potential prognostic and therapeutic value.

Adult↗
PubMed2000

Evaluation of patient-administered tampon specimens for Chlamydia trachomatis and Neisseria gonorrhoeae.

BACKGROUND: The patient-administered tampon specimen has proven to be an easy and sensitive method for the diagnosis of genital Chlamydia trachomatis and Neisseria gonorrhoeae infections in women by polymerase chain reaction (PCR). This method avoids the need for endocervical sampling and stringent criteria for transport. GOAL: To evaluate two commercial amplification systems for the detection of C trachomatis and N gonorrhoeae from tampon specimens. STUDY DESIGN: A group of 400 positive and negative tampon specimens tested by an in-house PCR method were selected from a pool of more than 2,000 previously collected tampons. Overall, 93 C trachomatis-positive and 77 N gonorrhoeae-positive specimens were evaluated. Each specimen was tested by Roche Cobas Amplicor and Abbott LCx (LCR), and results were compared to the in-house PCR method. RESULTS: Detection of C trachomatis by both assays was not significantly different from the in-house PCR assay. Fewer tampons were positive for N gonorrhoeae by LCR than either the in-house assay (P = 0.0001) or by Roche Amplicor (P = 0.01). However, tampon specimens tested by Roche Amplicor required DNA extraction to achieve comparative sensitivity. CONCLUSION: Both commercial assays can be applied to tampon-collected specimens for automated detection of sexually transmitted diseases. The detection of C trachomatis was similar to the in-house PCR test for both assays (P = 0.73, 0.68). Detection of N gonorrhoeae resulted in fewer positive tampon specimens when tested by ligase chain reaction than both Roche Amplicor and in-house PCR.

Chlamydia Infections↗
PubMed2000

Prevalence of sexually transmitted infections among clients of female commercial sex workers in Thailand.

BACKGROUND: Clients of commercial sex workers are considered at high risk for the acquisition and transmission of sexually transmitted diseases (STDs). Identification and treatment of infections in this group could help to reduce the transmission of STDs. GOAL: To ascertain the prevalence of sexually transmitted organisms in male clients of female sex workers in Thailand by analysis of seminal fluid collected after intercourse. STUDY DESIGN: Used condoms were collected from 291 male clients attending a brothel in Hat Yai, Thailand during a 7-day period. Nucleic acid was extracted from seminal fluid and tested by polymerase chain reaction for the presence of Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, herpes simplex virus (HSV) and HIV sequences. RESULTS: Overall, 17 (6%), 47 (16%), and 2 (1%) of specimens were positive for C trachomatis, N gonorrhoeae and T vaginalis respectively. HSV sequences were found in 24 (8%) of the specimens: 14 specimens (5%) with HSV type 1, and 11 specimens (4%) with HSV type 2. HIV RNA was detected in two samples (1%). Overall, 75 specimens (26%) were positive for one or more infections, and more than one pathogen was detected in 16 specimens (5%). CONCLUSION: This study reports a high rate of STDs among clients of female sex workers in Thailand. Consequently, this population is a significant risk for transmitting STDs to commercial sex workers and to other noncommercial partners. Strategies that target this population of men are needed to reduce STD and HIV transmission.

DNA Primers↗