Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Robert P. Kohn is active.

Publication


Featured researches published by Robert P. Kohn.


Journal of Acquired Immune Deficiency Syndromes | 2006

Detection of Acute HIV Infections in High-Risk Patients in California

Pragna Patel; Jeffrey D. Klausner; Oliver Bacon; Sally Liska; Melanie M. Taylor; Anthony Gonzalez; Robert P. Kohn; William Wong; Sydney Harvey; Peter R. Kerndt; Scott D. Holmberg

Background: Given the strong relation between sexually transmitted diseases (STDs) and the spread of HIV infection, recent outbreaks of syphilis in the United States could lead to increased rates of new HIV infection. STD clinics serving persons at risk for syphilis would be logical sites to monitor rates of acute HIV infection. The detection of acute HIV infection, however, is not routine and requires the use of HIV RNA testing in combination with HIV antibody testing. Methods: To determine the rate of acute HIV infection, we performed HIV RNA testing on pooled HIV antibody-negative specimens from persons seeking care at San Francisco City Clinic (SFCC) and from men seeking care at 3 STD clinics in Los Angeles. We compared prevalence of acute HIV infection among those groups. Results: From October 2003 to July 2004, we tested 3075 specimens from persons at the SFCC, of which 105 (3%) were HIV antibody-positive and 11 were HIV RNA-positive/HIV antibody-negative, resulting in a prevalence of acute HIV infection of 36 per 10,000 (95% confidence interval [CI]: 26 to 50 per 10,000) and increasing by 10.5% the diagnostic yield of HIV RNA testing compared with standard testing. From February 2004 to April 2004, 1712 specimens were tested from men at 3 Los Angeles STD clinics, of which 14 (0.82%) were HIV-positive by enzyme immunoassay testing and 1 was HIV RNA-positive/HIV antibody-negative, resulting in a prevalence of 6 per 10,000 (95% CI: 3 to 13 per 10,000) and increasing the diagnostic yield for HIV infection by 7.1%. Conclusions: In our study, the addition of HIV RNA screening to routine HIV antibody testing in STD clinics identified a substantial increased proportion of HIV-infected persons at high risk for further HIV transmission, who would have been missed by routine HIV counseling and testing protocols. Further evaluation of the addition of HIV RNA screening to routine HIV antibody testing is warranted.


Clinical Infectious Diseases | 2009

Chlamydia trachomatis and Neisseria gonorrhoeae Transmission from the Oropharynx to the Urethra among Men who have Sex with Men

Kyle T. Bernstein; Sally C. Stephens; Pennan M. Barry; Robert P. Kohn; Susan S. Philip; Sally Liska; Jeffrey D. Klausner

BACKGROUND Limited data exist on the risk of Chlamydia trachomatis and Neisseria gonorrhoeae transmission from oropharynx to urethra. We examined urethral C. trachomatis and N. gonorrhoeae positivity among men who have sex with men (MSM) seen at San Francisco City Clinic (San Francisco, CA) during 2007. METHODS All patients who sought care at the San Francisco City Clinic (the only municipal sexually transmitted disease clinic in San Francisco) received a standardized interview conducted by clinicians. We estimated urethral C. trachomatis and N. gonorrhoeae positivity for 2 groups of visits by MSM who visited during 2007: (1) men who reported their only urethral exposure was receiving fellatio in the previous 3 months and (2) men who reported unprotected insertive anal sex in the previous 3 months. Additionally, urethral C. trachomatis and N. gonorrhoeae positivity was estimated, stratified by human immunodeficiency virus infection status, urogenital symptom history, and whether the patient had been a contact to a sex partner with either chlamydia or gonorrhea. RESULTS Among MSM who reported only receiving fellatio, urethral C. trachomatis and N. gonorrhoeae positivity were 4.8% and 4.1%, respectively. These positivity estimates were similar to positivity found among MSM who reported unprotected insertive anal sex. CONCLUSIONS A more complete understanding of the risks of transmission of C. trachomatis and N. gonorrhoeae from oropharynx to urethra will help inform prevention and screening programs.


Clinical Infectious Diseases | 2004

Etiology of Clinical Proctitis among Men Who Have Sex with Men

Jeffrey D. Klausner; Robert P. Kohn; Charlotte K. Kent

In this retrospective review of cases of clinical proctitis, we identified the frequency of common sexually transmitted diseases (STDs) among men who have sex with men on the basis of reports from the municipal STD clinic in San Francisco. Of note, gonorrhea and chlamydia were the most common STDs, followed by herpes and syphilis. Current STD treatment guidelines recommend empiric treatment for gonorrhea and chlamydia, but treatment for herpes should also be considered. The implications for human immunodeficiency virus (HIV) transmission are also discussed.


Sexually Transmitted Diseases | 2011

Infections missed by urethral-only screening for chlamydia or gonorrhea detection among men who have sex with men.

Julia L. Marcus; Kyle T. Bernstein; Robert P. Kohn; Sally Liska; Susan S. Philip

In a retrospective analysis of asymptomatic men who have sex with men visiting an urban municipal sexually transmitted disease clinic, 83.8% of chlamydial and gonococcal infections would have been missed by urethral screening, compared with 9.8% by screening the rectum and pharynx. Extragenital screening is critical to the provision of comprehensive sexual health services for men who have sex with men.


Sexually Transmitted Diseases | 2010

Molecular Epidemiology of Syphilis-San Francisco, 2004-2007

Kenneth A. Katz; Allan Pillay; Katherine Ahrens; Robert P. Kohn; Keith Hermanstyne; Kyle T. Bernstein; Ronald C. Ballard; Jeffrey D. Klausner

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.


PLOS ONE | 2007

Declining Rates in Male Circumcision amidst Increasing Evidence of its Public Health Benefit

Zohar Mor; Charlotte K. Kent; Robert P. Kohn; Jeffrey D. Klausner

Background Recent experimental evidence has demonstrated the benefits of male circumcision for the prevention of human immunodeficiency virus (HIV) infection. Studies have also shown that male circumcision is cost-effective and reduces the risk for certain ulcerative sexually transmitted diseases (STDs). The epidemiology of male circumcision in the United States is poorly studied and most prior reports were limited by self-reported measures. The study objective was to describe male circumcision trends among men attending the San Francisco municipal STD clinic, and to correlate the findings with HIV, syphilis and sexual orientation. Methods and Findings A cross sectional study was performed by reviewing all electronic records of males attending the San Francisco municipal STD clinic between 1996 and 2005. The prevalence of circumcision over time and by subpopulation such as race/ethnicity and sexual orientation were measured. The findings were further correlated with the presence of syphilis and HIV infection. Circumcision status was determined by physical examination and disease status by clinical evaluation with laboratory confirmation. Among 58,598 male patients, 32,613 (55.7%, 95% Confidence Interval (CI) 55.2–56.1) were circumcised. Male circumcision varied significantly by decade of birth (increasing between 1920 and 1950 and declining overall since the 1960s), race/ethnicity (Black: 62.2%, 95% CI 61.2–63.2, White: 60.0%, 95% CI 59.46–60.5, Asian Pacific Islander: 48.2%, 46.9–49.5 95% CI, and Hispanic: 42.2%, 95% CI 41.3–43.1), and sexual orientation (gay/bisexual: 73.0%, 95% CI 72.6–73.4; heterosexual: 66.0%, 65.5–66.5). Male circumcision may have been modestly protective against syphilis in HIV-uninfected heterosexual men (PR 0.92, 95% C.I. 0.83–1.02, P = 0.06). Conclusions Male circumcision was common among men seeking STD services in San Francisco but has declined substantially in recent decades. Male circumcision rates differed by race/ethnicity and sexual orientation. Given recent studies suggesting the public health benefits of male circumcision, a reconsideration of national male circumcision policy is needed to respond to current trends.


Sexually Transmitted Diseases | 2008

Prevalence of rectal Trichomonas vaginalis and Mycoplasma genitalium in male patients at the San Francisco STD clinic, 2005-2006.

Suzanna C. Francis; Charlotte K. Kent; Jeffrey D. Klausner; Leah Rauch; Robert P. Kohn; Andrew Hardick; Charlotte A. Gaydos

Sexually transmitted infections (STI), such as Chlamydia trachomatis, Neisseria gonorrhoeae, Herpes Simplex Virus (HSV), and Treponema pallidum, are common causes of proctitis among gay men and other men who have sex with men (MSM) [1, 2]. Inflammatory proctitis caused by an STI may increase the susceptibility and infectivity of HIV[3, 4]. In many cases of proctitis, however, no etiological organism is detected[1]. The advent of nucleic acid amplification techniques (NAATs) presents an opportunity to detect organisms previously difficult to isolate from the rectum. Two such organisms, Trichomonas vaginalis and Mycoplasma genitalium, have been implicated in male urethritis, female cervicitis and endometrial infection[5-11].


Journal of Acquired Immune Deficiency Syndromes | 2007

HIV partner notification outcomes for HIV-infected patients by duration of infection, San Francisco, 2004 to 2006.

Katherine Ahrens; Charlotte K. Kent; Robert P. Kohn; Giuliano Nieri; Andrew Reynolds; Susan S. Philip; Jeffrey D. Klausner

Background:The San Francisco Department of Public Health conducts HIV third-party partner notification in the following populations based on standard Centers for Disease Control and Prevention (CDC) guidelines: (1) persons with acute and nonacute incident HIV infection tested at the municipal sexually transmitted disease (STD) clinic and the county hospital and (2) all county residents with early syphilis and long-standing HIV infection. Methods:We reviewed routinely collected demographic and partner notification outcome data among acute and nonacute cases between 2004 and 2006 and among long-standing cases between July 2005 and December 2006. Outcomes were examined among the 3 case types. Results:Most acute (n = 30), nonacute (n = 398), and long-standing cases (n = 335) occurred in gay/bisexual men (89%), and most case-patients were interviewed (80%). In acute and nonacute cases, 13% of partners tested for HIV were newly identified as HIV-infected. The number of patients interviewed per new HIV infection identified was 25 for acute cases, 21 for nonacute cases, and 39 for long-standing cases; however, half of recent new HIV infections were identified among partners of long-standing patients. Few patients or partners refused partner notification services. Conclusions:Partner notification was acceptable and successfully identified new HIV infections. Other jurisdictions should consider implementing or expanding partner notification for HIV infection. More evaluation is needed of the effectiveness of partner notification among HIV-infected persons with other STDs.


Sexually Transmitted Diseases | 2011

Evaluation of self-collected versus clinician-collected swabs for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae pharyngeal infection among men who have sex with men.

Alexandra H. Freeman; Kyle T. Bernstein; Robert P. Kohn; Susan S. Philip; Leah Rauch; Jeffrey D. Klausner

We evaluated self-sampling to detect pharyngeal Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infection among men who have sex with men attending a San Francisco STD clinic. The prevalence of pharyngeal NG and CT infection was 6.7% (32/480) and 1.3% (6/480), respectively. The percent agreement between self-collected and clinician-collected NG and CT specimens using nucleic acid amplification testing was 96.6% with a κ of 0.766 (95% confidence interval: 0.653-0.879) and 99.4% with a κ of 0.766 (95% confidence interval: 0.502-1.000), respectively. Acceptability was high among participants.


Sexually Transmitted Diseases | 2010

Prevalence and correlates of Trichomonas vaginalis among incarcerated persons assessed using a highly sensitive molecular assay.

Alexandra H. Freeman; Kenneth A. Katz; Mark Pandori; Leah Rauch; Robert P. Kohn; Sally Liska; Kyle T. Bernstein; Jeffrey D. Klausner

We describe the epidemiology of Trichomonas vaginalis (TV) among San Francisco County Jail inmates using APTIMA TV analyte-specific reagents on remnant urine. We detected TV in 15/713 (2.1%) men and 95/297 (32.0%) women. Among women, increased age was significantly associated with TV. The benefits of TV screening should be determined.

Collaboration


Dive into the Robert P. Kohn's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Kyle T. Bernstein

Centers for Disease Control and Prevention

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Charlotte K. Kent

Centers for Disease Control and Prevention

View shared research outputs
Top Co-Authors

Avatar

Sally Liska

Public health laboratory

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge