Category: Bacteria

Transmitting an STI and the law

On May 8 2014 the UK Court of Appeal dismissed the appeal of David Golding against a 14 month prison sentence for transmitting herpes to his partner.

An Editorial in the BMJ by Emily Clarke an colleagues highlights the numerous and  complicated issues that arise from this verdict including:

what constitutes grievous bodily harm,

how you determine that sexual transmission has occurred,

how serious is herpes infection, and

what this judgement means both for health care workers who advise and inform patients on the risks of transmission and on the infected individual and their duty of informing all partners of potential risk of transmitting an infection even during asymptomatic shedding.

The Editorial correctly highlights the dangers of criminalizing sexually transmitted infections and the various problems that arise from this judgement which was based on a law passed 170 years ago addressing totally unrelated issues and at a time when STI’s were not understood as they are today.

Bacteria living in men’s penises could be promoting sexually transmitted infections

The debate about whether to circumcise or not continues to raise passions. The fact that male circumcision reduces acquisition of HIV from an infected partner has been proven by three randomised clinical trials. And male circumcision may also protect against other sexually transmitted infections.

One of the most powerful arguments against male circumcision is that it only addresses acquired infections in the male. A recent report in the Scientist that bacteria living under the foreskin can promote STI’s would help answer this critique.

Just as the vaginal microbiome differs among women and changes over time, the penis is home to a variety of bacteria that vary with age, sexual activities, and whether the man is circumcised, among other things. And it’s not just the skin that envelops the male sexual organ that’s inhabited by microbes: researchers continue to identify bacteria that dwell within the urogenital tract, a site once considered sterile in the absence of infection.

David Nelson and colleagues at Indiana University in Bloomington found evidence to suggest that the sexually transmitted pathogens in the urogenital tract were obtaining metabolites from other microbes. “There was a signature in the chlamydial genome that suggested this organism might be interacting with other microorganisms,” said Nelson. “That’s what initially piqued our interest. And when we went in and started to look, we found that there were a lot more [microbes] than we would have anticipated being there.”

The researchers found that some men pass urine containing a variety of lactobacilli and streptococci species, whereas others have more anaerobes, like Prevotella and Fusobacterium. In terms of overall composition, “we see a lot of parallels to the gut,” said Nelson, noting that there doesn’t seem to be a standout formula for a “healthy” urogenital tract. Commensal microbes within the urethra could make a man more susceptible to infection by supporting colonization by pathogens like Chlamydia, whereas bacteria that consume the environment’s nutrients could help prevent it. “We just don’t know at this point,” said Nelson.

To date, circumcision is the known largest influence on the composition of the penis microbiome. In a 2010 PLOS ONE paper, Lance Price of the Translational Genomics Research Institute in Phoenix, Arizona, and his colleagues showed that the bacteria that colonized the base of the penis’s tip, or glans, varied before and after circumcision. More specifically, the researchers found fewer anaerobic bacteria within six months after the men in a study were circumcised. Those findings have since been confirmed.

Definitely further studies in this field should be encouraged.

Sexual health of female sex worker in the UK

Female sex workers (FSWs) are assumed to be at increased risk of sexually transmitted infections (STIs). Using routine STI surveillance data, McGrath-Lone et al  in an article published in the latest issue of Sexually Transmitted Infections investigated differences in sexual health between FSWs and other female attendees at sexual health (genitourinary medicine – GUM) clinics in England.

They reported on 2704 FSWs visiting to 131/208 GUM clinics, (primarily large, FSW-specialist centres in London) in 2011. By comparison with other female attendees, FSWs travelled further for their care and had increased risk of certain STIs (eg, gonorrhoea Odds Ratio: 2.76, p<0.001). Significantly migrant FSWs had better sexual health outcomes than UK-born FSWs (eg, period prevalence of chlamydia among those tested: 8.5% vs 13.5%, p<0.001) but were more likely to experience non-STI outcomes (eg, pelvic inflammatory disease OR: 2.92, p<0.001).

They concluded that although FSWs in England have access to high-quality care through the GUM clinic network, there was evidence of geographical inequality in access to these services.

A minority do not appear to access STI/HIV testing through clinics, and some STIs are more prevalent among FSWs than other female attendees.

Targeted interventions aimed at improving uptake of testing in FSWs should be developed, and need to be culturally sensitive to the needs of this predominantly migrant population.

Bacterial vaginosis fact sheet update by CDC

Bacterial vaginosis (BV) is the commonest vaginal infection seen in women. The Centre of Disease Control (CDC) has recently updated its fact sheet on this common condition.

In summary 

BV is linked to an imbalance of “good” and “harmful” bacteria that are normally found in a woman’s vagina. Having a new sex partner or multiple sex partners and douching can upset the balance of bacteria in the vagina and put women at increased risk for getting BV.

BV can cause some serious health risks, including:

Increasing your chance of getting HIV if you have sex with someone who is infected with HIV;

If you are HIV positive, increasing your chance of passing HIV to your sex partner;

Making it more likely that you will deliver your baby too early if you have BV while pregnant;

Increasing your chance of getting other STDs, such as chlamydia and gonorrhoea.

These bacteria can sometimes cause pelvic inflammatory disease (PID), which can make it difficult or impossible for you to have children.

Important new research on lymphogranuloma venereum (LGV) in gay men in the UK

Lymphogranuloma venereum (LGV), previously predominantly a tropical disease, re-emerged in Western Europe in 2003, and has arguably now regained endemic status in many countries. It remains largely contained within in a population of men who have sex with men (MSM) with high rates of other sexually transmitted infections (STIs) including HIV, though a first female case was reported in Sexually Transmitted Infections in 2012.

A recent series of papers in Sexually Transmitted Infections sheds further light on the risk factors for rectal LGV in men who have sex with men in the UK, the key symptoms and ways in which LGV presents to the clinician, and pitfalls in the currently recommended treatment and prevention strategies.

Moreover, microbiological  characteristic of LGV repeaters using surveillance data has convinced Rönn and colleagues that behaviour alone does not explain reinfection, which they see as related to centrality in sexual networks.

Together these four articles add important information on the clinical presentation, epidemiology and treatment of LGV in MSM.

Bacterial vaginosis (BV): a common cause of vaginal discharge in need of more research

Bacterial vaginosis (BV) is a common condition in women presenting as a malodorous vaginal discharge. The  smell is often worse after sex and arround the menstrual period. Occasionally there is an associated  itching or burning sensation although most women with BV only have the discharge. BV can also be detected in women who are totally symptom free.

BV is caused by an imbalance of the normal vagina flora and its mechanism remain poorly understood. An updated review by the Centre for Disease Control (CDC), USA confirms a commonly observation that BV follows sexual intercourse with a new partner and multiple partners as well as vaginal douching.

BV, itself an benign though troublesome nuisance is associated with increased risk of a number of infections or conditions:

  • Having BV can increase a woman’s susceptibility to HIV infection if she is exposed to the HIV virus.

  • Having BV increases the chances that an HIV-infected woman can pass HIV to her sex partner.

  • Having BV has been associated with an increase in the development of an infection following surgical procedures such as a hysterectomy or an abortion.

  • Having BV while pregnant may put a woman at increased risk for some complications of pregnancy, such as preterm delivery.

  • BV can increase a woman’s susceptibility to other STDs, such as herpes simplex virus (HSV),chlamydia, and gonorrhea.

  • The bacteria that cause BV can sometimes infect the uterus (womb) and fallopian tubes (tubes that carry eggs from the ovaries to the uterus). This type of infection is called pelvic inflammatory disease (PID).
  • Pregnant women with BV more often have babies who are born premature or with low birth weight (low birth weight is less than 5.5 pounds). Pregnant women who have had previous premature of low birth weight babies should be tested and treated for BV in third trimester regardless of symptoms.

What is in the May issue of STI

The latest issue of STI (Sexually Transmitted Infections) contains articles on increasing resistance of bacterial STI’s, a successful  educational interventions in South London to encourage HIV testing and data supporting the willingness by a substantial section of men who have sex with men to use pre-exposure prophylaxis for HIV.

particularly worrying is the emergence of a novel strategy by the gonococcus to avoid detection by the now widely used DNA amplification methods.

Self-taking vaginal sample best test for chlamydia and gonorrhoea in women

The optimal diagnostic sample for Chlamydia trachomatis detection should detect the maximum number of infected people.  In women without symptoms the sample of choice is a self taken vulvovaginal swab, which can be done in the privacy of one’s home. But it is not clear whether a vulvovaginal swab or an endocervical swab is the optimum sample in women with symptoms requiring speculum examination.

A recent study by Sarah Shoeman and colleagues published in the BMJ compared the two sampling methods. They showed that in women attending a sexual health centre vulvovaginal swabs were significantly better at detecting chlamydia infection than endocervical swabs among women with symptoms of a sexually transmitted infection.

In these cases, using endocervical samples rather than vulvovaginal swabs would have missed 9% of infections, or 1 in 11 cases of chlamydia infection

A  parallel  study by the same group showed that self taken vaginal swabs tested by the  Nucleic acid amplification tests (NAATs) which offer increased sensitivity for detecting gonorrhoea, is significantly more sensitive and offers good specificity for detecting gonorrhoea compared with standard gonorrhoea culture methods.

However  confirmation of positive results with a second NAAT is essential in low prevalence populations such as the UK, to avoid false positive results

Women and clinicians can be confident that self taken vulvovaginal swabs are as accurate as clinician performed tests for the detection of chlamydia and gonorrhoea in women without symptoms and should be the test method of choice in asymptomatic women.

Lancet issue on the state of global health

The Lancet has devoted an entire issue to various aspects of global health. The issue is available free for download.

An edited extract from the executive summary follows:

The Global Burden of Disease Study 2010 (GBD 2010) is the largest ever systematic effort to describe the global distribution and causes of a wide array of major diseases, injuries, and health risk factors.

The results show that infectious diseases, maternal and child illness, and malnutrition now cause fewer deaths and less illness than they did twenty years ago. As a result, fewer children are dying every year, but more young and middle-aged adults are dying and suffering from disease and injury.

Thus non-communicable diseases, such as cancer and heart disease, become the dominant causes of death and disability worldwide.

Since 1970, men and women worldwide have gained slightly more than ten years of life expectancy overall, but they spend more years living with injury and illness.