Antichlamydial activity of saliva

Pharmacokinetic considerations regarding the treatment of bacterial sexually transmitted infections with azithromycin: a review

Rates of bacterial sexually transmitted infections (STIs) continue to rise, demanding treatments to be highly effective. However, curing infections faces significant challenges due to antimicrobial resistance in Neisseria gonorrhoeae and Mycoplasma genitalium and especially treating STIs at extragenital sites, particularly rectal chlamydia and oropharyngeal gonorrhoea. As no new antimicrobials are entering the market, clinicians must optimize the currently available treatments, but robust data are lacking on how the properties or pharmacokinetics of antimicrobials can be used to inform STI treatment regimens to improve treatment outcomes. This paper provides a detailed overview of the published pharmacokinetics of antimicrobials used to treat STIs and how factors related to the drug (tissue distribution, protein binding and t½), human (pH, inflammation, site of infection, drug side effects and sexual practices) and organism (organism load and antimicrobial resistance) can affect treatment outcomes. As azithromycin is commonly used to treat chlamydia, gonorrhoea and M. genitalium infections, and its pharmacokinetics are well studied, it is the main focus of this review. Suggestions are also provided on possible dosing regimens when using extended and/or higher doses of azithromycin, which appropriately balance efficacy and side effects. The paper also emphasizes the limitations of currently published pharmacokinetic studies including oropharyngeal gonococcal infections, where very limited data exist around ceftriaxone pharmacokinetics and its use in combination with azithromycin. In future, the different anatomical sites of infections may require alternative therapeutic approaches.

Role of saliva use during masturbation in the transmission of Chlamydia trachomatis in men who have sex with men

Masturbation is a common sexual practice in men, and saliva is often used as a lubricant during masturbation by men who have sex with men. However, the role of saliva use during masturbation in the transmission of chlamydia is still unclear. We developed population-level, susceptible-infected-susceptible compartmental models to explore the role of saliva use during masturbation on the transmission of chlamydia at multiple anatomical sites. In this study, we simulated both solo masturbation and mutual masturbation. Our baseline model did not include masturbation but included transmission routes (anal sex, oral-penile sex, rimming, kissing and sequential sexual practices) we have previously validated (model 1). We added masturbation to model 1 to develop the second model (model 2). We calibrated the model to five clinical datasets separately to assess the effects of masturbation on the prevalence of site-specific infection. The inclusion of masturbation (model 2) significantly worsened the ability of the models to replicate the prevalence of C. trachomatis. Using model 2 and the five data sets, we estimated that saliva use during masturbation was responsible for between 3.9% [95% confidence interval (CI) 2.0–6.8] and 6.2% (95% CI 3.8–10.5) of incident chlamydia cases at all sites. Our models suggest that saliva use during masturbation is unlikely to play a major role in chlamydia transmission between men, and even if it does have a role, about one in seven cases of urethral chlamydia might arise from masturbation.

The role of saliva in gonorrhoea and chlamydia transmission to extragenital sites among men who have sex with men: new insights into transmission

INTRODUCTION

Gonorrhoea and chlamydia cases have been rising among gay, bisexual and other men who have sex with men (MSM) over the last decade. The majority of cases are extragenital and occur at the oropharynx and anorectum. The aim of this narrative review was to review the risk factors and mode of transmission for gonorrhoea and chlamydia at the oropharynx and anorectum among MSM.

RESULTS AND DISCUSSION

New evidence suggests that oropharyngeal gonorrhoea can be transmitted by kissing in addition to through the established route of condomless oral sex; and anorectal gonorrhoea can be acquired when saliva is used as a lubricant for anal sex and rimming in addition to the established route of condomless penile-anal sex in MSM. In contrast, condomless penile-anal sex remains the major route for chlamydia transmission.

CONCLUSIONS

Substantial transmission of gonorrhoea may occur with practices other than the established routes of condomless oral and/or anal sex and hence condoms may not be effective in preventing gonorrhoea transmission to extragenital sites. In contrast, condoms are effective for chlamydia control because it is mainly transmitted through condomless penile-anal sex. Novel interventions for gonorrhoea that reduce the risk of transmission at extragenital site are required.

Factors associated with anorectal Chlamydia trachomatis or Neisseria gonorrhoeae test positivity in women: a systematic review and meta-analysis

OBJECTIVES

There has been considerable discussion about anorectal Chlamydia trachomatis (CT) in women, with some calling for anorectal CT screening, but little about anorectal Neisseria gonorrhoeae (NG). Given that urogenital NG is more strongly associated with pelvic inflammatory disease, this is an evidence gap. This systematic review and meta-analysis investigates the associations between anorectal CT in women and CT positivity at other sites (urogenital/oropharyngeal) and with anal intercourse, and compares these with anorectal NG within the same study populations.

METHODS

Electronic databases were searched for English-language studies published to October 2018 using the following terms: ("Chlamydia" OR "Chlamydia trachomatis") AND (("anal" OR "rect*" OR "anorect*") OR ("extra?genital" OR "multi?site")). Studies were included if anorectal NG data were available. Random-effects meta-analyses calculated pooled estimates; heterogeneity was investigated using meta-regression.

RESULTS

25 studies were eligible. Anorectal CT positivity ranged from 0% to 17.5%, with a summary estimate of 8.0% (95% CI 7.0 to 9.1; I²=88.5%). Anorectal NG positivity ranged from 0% to 17.0%, with a summary estimate of 2.1% (95% CI 1.6 to 2.8; I²=92.7%). The association between urogenital and anorectal positivity was stronger for NG than CT (summary prevalence ratio (PR)=89.3 (95% CI 53.1 to 150.3; I²=80.1%), PR=32.2 (95% CI 25.6 to 40.7; I²=70.3%), respectively), and between oropharyngeal and anorectal positivity it was stronger for NG than CT (PR=34.8 (95% CI 10.2 to 118.2; I²=89.9%), PR=8.8 (95% CI 6.8 to 11.5; I²=58.1%), respectively). Anal intercourse was associated with anorectal NG (PR=4.3; 95% CI 2.2 to 8.6; I²=0.0%) but not with anorectal CT (PR=1.0; 95% CI 0.7 to 1.4; I²=0.0%).

CONCLUSIONS

Anorectal CT is more common than anorectal NG, but anorectal NG is more strongly associated with anal intercourse, urogenital and oropharyngeal NG, suggesting that ongoing discussion about anorectal CT should also include NG. Longitudinal data are required to further understanding of the aetiology of anorectal STIs and assess whether anorectal screening is needed in women.

TRIAL REGISTRATION NUMBER

CRD42df017080188.

Antichlamydial activity of vaginal secretion

OBJECTIVE

The purpose of this study was to investigate the possible antichlamydial activity of vaginal secretion and to partially characterize the inhibitory principle.

STUDY DESIGN

Vaginal secretions obtained from 156 women attending a family planning or gynecologic outpatient clinic for contraceptive advice were studied for the influence on the inclusion formation of Chlamydia trachomatis in cycloheximide-treated McCoy cell cultures.

RESULTS

Vaginal secretions from 156 women inhibited the inclusion formation of Chlamydia trachomatis. The inhibition was concentration dependent and the inhibitory principle had a molecular weight of < 10,000 d. It was heat labile. It was not related to antichlamydial antibodies in vaginal secretions. Only three (2%) of the women had a positive culture for Chlamydia trachomatis. Three had immunoglobulin A and three had immunoglobulin G antichlamydial antibodies in vaginal secretions. Secretions of those with a vaginal pH of 3.5 to 4.5 decreased the chlamydial inclusion count by 75% compared with controls. The corresponding percentage for those with a pH of 5.0 to 6.0 was 48% and for those with pH > 6 was 33%. Vaginal secretions of oral contraceptive users and nonusers did not differ in the capacity to decrease the chlamydial inclusion count, p > 0.01.

CONCLUSIONS

When vaginal secretions were added to McCoy cell cultures infected by Chlamydia trachomatis, the chlamydia inclusion number decreased. There was a correlation between pH of the vaginal secretion and the inhibitory principle. Oral contraceptive use had no influence on the inhibition.

A contemporary view of salivary research

The past 50 years of salivary research has been marked by a series of changing perceptions as new techniques and technologies have illuminated the complexities of the secretory mechanism, salivary composition, and function. The modern era began with the innovations of electrophoresis, chromatography, histochemistry, immunochemistry, electron microscopy, and microphysiology. The idea of saliva as primarily a digestive fluid composed of salts, amylase, and mucin was rapidly broadened to encompass a wide spectrum of protective proteins with the dual responsibility of protecting both hard and soft tissues. Characterization of the secretory IgA and nonimmunological antibacterial systems and the proteins responsible for the regulation of calcium and phosphate levels dominated the research in the 1960s and 1970s. An appreciation of the nature, formation, and role of the salivary pellicle and the interplay between bacterial adherence and agglutination provided a clinical thrust. Morphologists and physiologists redefined the secretory process on a molecular level. The 1980s saw the union of structure and function, both in terms of synthesis and release of the secretory products and their specific roles in the oral cavity in health and disease. The excitement of the 1990s is in the genetic control of processes and products, elucidating the mechanisms, and using the information to improve on nature: an era of great expectations and hubris. This article is essentially a personal guided tour through the past 50 years of salivary research.

Age-dependent antichlamydial activity of human saliva. A study of infants, children and adults

Saliva samples from 51 children ranging from 1 month to 12 years of age were studied for their effect on the capacity of Chlamydia trachomatis, serotypes I and L2 elementary bodies (EB), to form inclusions in cycloheximide-treated McCoy cell cultures. The results were compared to those of tests using saliva from adults. No antibodies against C. trachomatis or Chlamydia pneumoniae could be detected by microimmunofluorescence tests in either group. Saliva of children between 1-4 years of age showed an age-related decrease in the chlamydial inclusion count (i.c.). Saliva from children older than 4 years of age, like saliva from healthy adults, showed a pronounced reduction of the i.c. (up to 70%). The study indicates that children between 1-4 years gradually develop a natural antichlamydial activity against C. trachomatis, and above that age they exhibit the same level of antichlamydial activity as adults. The inhibitory activity was heat-resistant.

Influence of whole human milk, and fractions thereof, on inclusion-formation of Chlamydia trachomatis in McCoy cells

A study of the effect of human breast milk, and components thereof, on the capacity of Chlamydia trachomatis to form inclusions in cycloheximide-treated McCoy cells, was undertaken. Pooled whole milk collected during the first week of breast feeding caused a concentration-dependent inhibition of the chlamydial inclusion-formation. The activity resided in the fat and fat globule membrane (FGM) components of the milk. The active principle in the FGM fraction is heat-stable and pronase-sensitive, but resistant to both neuraminidase and periodate. Immunoglobulins was not responsible for the inhibition. Whey and casein fractions of milk increased the chlamydial inclusion-formation. The activity of the whey was heat-stable, dose-related, and had a mol. wt. of greater than or equal to 12,000. The casein fraction was still active after heat treatment. Whey samples collected up to 28 days after delivery varied slightly in their stimulatory activity, with an optimum between the 7th and 14th days. The present study demonstrated a multieffect of breast milk on chlamydial inclusion-formation: an inhibitory activity due to a protein compound as well as another factor in the fat fraction and an enhancing effect due to a heat-stable factor(s).