Development of a rectal sexually transmitted infection (STI) Model in Rhesus macaques using Chlamydia trachomatis serovars E and L2

HIV Prevalence and Risk Factors Among Young Men Who Have Sex With Men in Southwest China: Cross-sectional Questionnaire Study

BACKGROUND

Previous studies showed an increase in HIV prevalence among young men who have sex with men aged 25 years or younger in China.

OBJECTIVE

This study aimed to assess HIV prevalence and associated factors among young men who have sex with men in the Guangxi Zhuang Autonomous Region.

METHODS

This study was conducted in 4 cities (Guilin, Liuzhou, Beihai, and Nanning) in the Guangxi Zhuang Autonomous Region between June 2014 and May 2016. Participants were reached through web-based and site recruitment approaches. Laboratory tests were performed to detect HIV and syphilis infections. A self-administered questionnaire was used to collect data from 632 eligible young men who have sex with men.

RESULTS

The prevalence of HIV and syphilis was 9.3% (59/632) and 11.4% (72/632), respectively. Multivariable logistic analysis showed that ethnic minority (adjusted odds ratio [AOR] for Han Chinese vs other minorities 0.28, 95% CI 0.11-0.71, P=.007), receptive sexual positioning in the past 6 months (AOR 2.94, 95% CI 1.32-6.53, P=.008), current syphilis infection (AOR for individuals without vs those with infection 0.38, 95% CI 0.19-0.75, P=.005), inconsistent condom use in the past 6 months (AOR 1.91, 95% CI 1.06-3.45, P=.03), and psychotropic drug use before last anal intercourse (AOR 16.70, 95% CI 2.34-119.18, P=.005) were independently associated with HIV infection.

CONCLUSIONS

There is an urgent need to scale up HIV and syphilis interventions in young men who have sex with men. Some subgroups might need specific attention for HIV prevention, including ethnic minority men, individuals with a history of sexually transmitted infections, and individuals who have been engaging in receptive anal sex.

Rhein inhibits Chlamydia trachomatis infection by regulating pathogen-host cell

The global incidence of genital Chlamydia trachomatis infection increased rapidly as the primary available treatment of C. trachomatis infection being the use of antibiotics. However, the development of antibiotics resistant stain and other treatment failures are often observed in patients. Consequently, novel therapeutics are urgently required. Rhein is a monomer derivative of anthraquinone compounds with an anti-infection activity. This study investigated the effects of rhein on treating C. trachomatis infection. Rhein showed significant inhibitory effects on the growth of C. trachomatis in multiple serovars of C. trachomatis, including D, E, F and L1, and in various host cells, including HeLa, McCoy and Vero. Rhein could not directly inactivate C. trachomatis but could inhibit the growth of C. trachomatis by regulating pathogen-host cell interactions. Combined with azithromycin, the inhibitory effect of rehin was synergistic both in vitro and in vivo. Together these findings suggest that rhein could be developed for the treatment of C. trachomatis infections.

Pubic Hair Grooming and Sexually Transmitted Infections: A Clinic-Based Cross-Sectional Survey

BACKGROUND

Pubic hair grooming has been correlated with a self-reported history of sexually transmitted infections (STIs). We examined this relationship further in a cross-sectional survey of patients attending an urban STI clinic in San Francisco in 2018.

METHODS

Pubic hair grooming practices and detailed sexual histories were obtained. Sexually transmitted infections were confirmed via laboratory diagnosis or physical examination by a licensed provider.

RESULTS

A total of 314 individuals completed the survey. The median age of participants was 31 years. In total, there were 247 (80%) men, 58 (19%) women, and 5 (2%) transgender participants. Of the 247 men, 177 (72%) identified as gay or bisexual. Twenty-five (82%) of 314 patients reported pubic hair grooming within the past 3 months. Seventy-eight (25%) patients were diagnosed with a new STI during their visit. There were no significant associations between reporting any anal or genital grooming and being diagnosed with an STI. However, anal groomers were 3 times as likely to be diagnosed with a rectal STI after adjustment (adjusted odds ratio, 3.0; 95% confidence interval, 1.2-7.5) compared with genital only groomers and nongroomers. Participants who report removing all of their pubic hair more than 6 times within the past year had higher prevalence of genital STIs (33.3%, 6-10 times; 28.6%, >10 times) compared with participants who never groom all of their pubic hair (15.3%, P = 0.01).

CONCLUSIONS

We found no association between recent grooming and genital STIs. Anal grooming was associated with rectal STIs in gay and bisexual men.

Animal Models of Type III Secretion System-Mediated Pathogenesis

The type III secretion system (T3SS) is a conserved virulence factor used by many Gram-negative pathogenic bacteria and has become an important target for anti-virulence drugs. Most T3SS inhibitors to date have been discovered using in vitro screening assays. Pharmacokinetics and other important characteristics of pharmaceuticals cannot be determined with in vitro assays alone. In vivo assays are required to study pathogens in their natural environment and are an important step in the development of new drugs and vaccines. Animal models are also required to understand whether T3SS inhibition will enable the host to clear the infection. This review covers selected animal models (mouse, rat, guinea pig, rabbit, cat, dog, pig, cattle, primates, chicken, zebrafish, nematode, wax moth, flea, fly, and amoeba), where T3SS activity and infectivity have been studied in relation to specific pathogens (Escherichia coli, Salmonella spp., Pseudomonas spp., Shigella spp., Bordetella spp., Vibrio spp., Chlamydia spp., and Yersinia spp.). These assays may be appropriate for those researching T3SS inhibition.

Survival and death of intestinal cells infected by Chlamydia trachomatis

The sexually transmitted pathogen Chlamydia trachomatis (CT) is able to replicate and survive in human intestinal epithelial cells, being the gastro-intestinal tract a suitable site of residence for this microorganism. In this context, no detailed information about the mechanisms of cell death in intestinal cell lines after a chlamydial infection is available. The aim of this study was to compare the effect of two different CT serovars (D and L2) on the survival/death of different intestinal cell lines (Caco-2 and COLO-205), using endocervical cells (HeLa) as a reference model of genital infection. Seventy two hours after chlamydial infection at different multiplicity of infection (MOI) levels, the viability of HeLa, Caco-2 and COLO 205 cells was evaluated through dose-response experiments by means of a MTS-based assay. To get deeper insights in the mechanisms of cell death induced by CT, cell viability was assessed in presence of different inhibitors (i.e. pan-caspase inhibitor Z-VAD, necroptosis inhibitor Necrostatin-1, hydrogen peroxide scavenger catalase, caspase-1 inhibitor Ac-YVAD-cmk). Moreover, the activation of effector caspases and the presence of cellular apoptotic/necrotic changes were evaluated at different time points after CT infection. Our results demonstrated that, for both chlamydial serovars, intestinal cell lines are more resistant to CT-induced cell death compared to HeLa, thus representing a suitable ‘niche’ for chlamydial residence and replication. In literature, apoptosis has been widely described to be the main cell death mechanism elicited by chlamydia infection. However, our data demonstrate that necroptosis plays a relevant role, proceeding in parallel with apoptosis. The protective effect of catalase suggests the involvement of oxidative stress in triggering both cell death pathways. Moreover, we demonstrated that caspase-1 is involved in CT-induced cell death, potentially contributing to host inflammatory response and tissue damage. Cells infected by L2 serovar displayed a higher activation of effector caspases compared to cells infected with serovar D, suggesting a serovar-specific activation of apoptotic pathways and potentially explaining the greater virulence of L serovars. Finally, we found that Chlamydia elicits the early externalization of phosphatidylserine on the external leaflet of plasma membrane independently of caspase activation.

Development of a repeat-exposure penile SHIV infection model in macaques to evaluate biomedical preventions against HIV

Penile acquisition of HIV infection contributes substantially to the global epidemic. Our goal was to establish a preclinical macaque model of penile HIV infection for evaluating the efficacy of new HIV prevention modalities. Rhesus macaques were challenged once or twice weekly with consistent doses of SHIV_sf162P3 (a chimeric simian-human immunodeficiency virus containing HIV env) ranging from 4–600 TCID₅₀ (50% tissue culture infective dose), via two penile routes, until systemic SHIV infection was confirmed. One route exposed the inner foreskin, glans and urethral os to virus following deposition into the prepuce (foreskin) pouch. The second route introduced the virus non-traumatically into the distal urethra only. Single-route challenges resulted in dose-dependent rates of SHIV acquisition informing selection of optimal SHIV dosing. Concurrent SHIV challenges via the prepuce pouch (200 TCID₅₀) and urethra (16 TCID₅₀) resulted in infection of 100% (10/10) animals following a median of 2.5 virus exposures (range, 1–12). We describe the first rhesus macaque repeat-exposure SHIV challenge model of penile HIV acquisition. Utilization of the model should further our understanding of penile HIV infection and facilitate the development of new HIV prevention strategies for men.