Prevalence of porA pseudogene deletion among Neisseria gonorrhoeae isolates referred to the UK's Gonococcal Resistance to Antimicrobials Surveillance Program

porA pseudogene-negative Neisseria gonorrhoeae isolates produce false-negative results when examined by polymerase chain reaction (PCR) with porA pseudogene targets. In the present study, 533 representative gonococcal isolates received in 2011 via the Gonococcal Resistance to Antimicrobials Surveillance Program were examined to determine the prevalence of porA-negative isolates. Less than 0.4% (2/533) of isolates were found to be reproducibly negative with the porA real-time PCR but were confirmed as N. gonorrhoeae with molecular, biochemical and immunological confirmatory tests. Sequencing revealed both isolates contained the Neisseria meningitidis porA gene. Low prevalence indicates that although these isolates do not present a major public health problem, microbiologists should remain vigilant.

Phenotypic antimicrobial susceptibility testing of Chlamydia trachomatis isolates from patients with persistent or successfully treated infections

Objectives

Antimicrobial susceptibility data for Chlamydia trachomatis are lacking. Methodologies for susceptibility testing in C. trachomatis are not well-defined, standardized or performed routinely owing to its intracellular growth requirements. We sought to develop an assay for the in vitro susceptibility testing of C. trachomatis isolates from two patient cohorts with different clinical outcomes.

Methods

Twenty-four clinical isolates (11 from persistently infected and 13 from successfully treated patients) were overlaid with media containing two-fold serial dilutions of azithromycin or doxycycline. After incubation, aliquots were removed from the stock inoculum (SI) and each antimicrobial concentration for total RNA extraction, complementary DNA generation and real-time PCR. The MIC was defined as the lowest antimicrobial concentration where a 95% reduction in transcription was evident in comparison with the SI for each isolate.

Results

MICs of azithromycin were comparable for isolates from the two patient groups (82% ≤ 0.25 mg/L for persistently infected and 100% ≤ 0.25 mg/L for successfully treated patients). Doxycycline MICs were at least two-fold lower for isolates from the successfully treated patients (53.9% ≤ 0.064 mg/L) than for the persistently infected patients (100% ≥ 0.125 mg/L) (P = 0.006, Fisher's exact test). Overall, 96% of isolates gave reproducible MICs when re-tested.

Conclusions

A reproducible assay was developed for antimicrobial susceptibility testing of C. trachomatis. MICs of azithromycin were generally comparable for the two different patient groups. MICs of doxycycline were significantly higher in the persistently infected patients. However, interpretation of elevated MICs in C. trachomatis is extremely challenging in the absence of breakpoints, or wild-type and treatment failure MIC distribution data.

Ten years of external quality assessment (EQA) of Neisseria gonorrhoeae antimicrobial susceptibility testing in Europe elucidate high reliability of data

Background

Confidence in any diagnostic and antimicrobial susceptibility testing data is provided by appropriate and regular quality assurance (QA) procedures. In Europe, the European Gonococcal Antimicrobial Susceptibility Programme (Euro-GASP) has been monitoring the antimicrobial susceptibility in Neisseria gonorrhoeae since 2004. Euro-GASP includes an external quality assessment (EQA) scheme as an essential component for a quality-assured laboratory-based surveillance programme. Participation in the EQA scheme enables any problems with the performed antimicrobial susceptibility testing to be identified and addressed, feeds into the curricula of laboratory training organised by the Euro-GASP network, and assesses the capacity of individual laboratories to detect emerging new, rare and increasing antimicrobial resistance phenotypes. Participant performance in the Euro-GASP EQA scheme over a 10 year period (2007 to 2016, no EQA in 2013) was evaluated.

Methods

Antimicrobial susceptibility category and MIC results from the first 5 years (2007–2011) of the Euro-GASP EQA were compared with the latter 5 years (2012–2016). These time periods were selected to assess the impact of the 2012 European Union case definitions for the reporting of antimicrobial susceptibility.

Results

Antimicrobial susceptibility category agreement in each year was ≥91%. Discrepancies in susceptibility categories were generally because the MICs for EQA panel isolates were on or very close to the susceptibility or resistance breakpoints. A high proportion of isolates tested over the 10 years were within one (≥90%) or two (≥97%) MIC log₂ dilutions of the modal MIC, respectively. The most common method used was Etest on GC agar base. There was a shift to using breakpoints published by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in the latter 5 years, however overall impact on the validity of results was limited, as the percentage categorical agreement and MIC concordance changed very little between the two five-year periods.

Conclusions

The high level of comparability of results in this EQA scheme indicates that high quality data are produced by the Euro-GASP participants and gives confidence in susceptibility and resistance data generated by laboratories performing decentralised testing.

Arterial ischemic stroke in HIV: Defining and classifying etiology for research studies

HIV infection, and potentially its treatment, increases the risk of an arterial ischemic stroke. Multiple etiologies and lack of clear case definitions inhibit progress in this field. Several etiologies, many treatable, are relevant to HIV-related stroke. To fully understand the mechanisms and the terminology used, a robust classification algorithm to help ascribe the various etiologies is needed. This consensus paper considers the strengths and limitations of current case definitions in the context of HIV infection. The case definitions for the major etiologies in HIV-related strokes were refined (e.g., varicella zoster vasculopathy and antiphospholipid syndrome) and in some instances new case definitions were described (e.g., HIV-associated vasculopathy). These case definitions provided a framework for an algorithm to help assign a final diagnosis, and help classify the subtypes of HIV etiology in ischemic stroke.

The clinical manifestations of anorectal infection with lymphogranuloma venereum (LGV) versus non-LGV strains of Chlamydia trachomatis: a case–control study in homosexual men

Lymphogranuloma venereum (LGV) has recently been reported in men who have sex with men. In a case–control study we compared behavioural and clinical features of 32 men with LGV (cases) and 31 men with non-LGV chlamydial proctitis (controls). LGV was associated with rectal discharge (odds ratio [OR] 4.15, 95% confidence interval [CI] 1.42, 12.2), and there was a tendency to association with HIV infection (OR 3.60, CI 0.67–19.4), sexual contact in the UK (OR 3.03, CI 1.02–9.01) and fisting (OR 5.04, CI 0.98–26.1). LGV should be considered a possible diagnosis in men with rectal discharge.

The incidence of congenital syphilis in the United Kingdom: February 2010 to January 2015

OBJECTIVE

To estimate the incidence of congenital syphilis in the UK.

DESIGN

Prospective study.

SETTING AND POPULATION

United Kingdom.

METHODS

Children born between February 2010 and January 2015 with a suspected diagnosis of congenital syphilis were reported through an active surveillance system.

MAIN OUTCOME MEASURES

Number of congenital syphilis cases and incidence.

RESULTS

For all years, reported incidence was below the WHO threshold for elimination (<0.5/1000 live births). Seventeen cases (12 male, five female) were identified. About 50% of infants (8/17) were born preterm (<37 weeks' gestation): median birthweight 2000 g (865-3170 g). Clinical presentation varied from asymptomatic to acute disease, including severe anaemia, hepatosplenomegaly, rhinitis, thrombocytopaenia, skeletal damage, and neurosyphilis. One infant was deaf and blind. Median maternal age was 20 years (17-31) at delivery. Where maternal stage of infection was recorded, 6/10 had primary, 3/10 secondary and 1/10 early latent syphilis. Most mothers were white (13/16). Country of birth was recorded for 12 mothers: UK (n = 6), Eastern Europe (n = 3), Middle East (n = 1), and South East Asia (n = 2). The social circumstances of mothers varied and included drug use and sex work. Some experienced difficulty accessing health care.

CONCLUSION

The incidence of congenital syphilis is controlled and monitored by healthcare services and related surveillance systems, and is now below the WHO elimination threshold. However, reducing the public health impact of this preventable disease in the UK is highly dependent on the successful implementation of WHO elimination standards across Europe.

TWEETABLE ABSTRACT

Congenital syphilis incidence in the UK is at a very low level and well below the WHO elimination threshold.

Asymptomatic Lymphogranuloma Venereum in Men who Have Sex with Men, United Kingdom

We investigated prevalence of lymphogranuloma venereum (LGV) among men who have sex with men who were tested for chlamydia at 12 clinics in the United Kingdom during 10 weeks in 2012. Of 713 men positive for Chlamydia trachomatis, 66 (9%) had LGV serovars; 15 (27%) of 55 for whom data were available were asymptomatic.

Can we use postal surveys with anonymous testing to monitor chlamydia prevalence in young women in England? Pilot study incorporating randomised controlled trial of recruitment methods

OBJECTIVES

Chlamydia prevalence in the general population is a potential outcome measure for the evaluation of chlamydia control programmes. We carried out a pilot study to determine the feasibility of using a postal survey for population-based chlamydia prevalence monitoring.

METHODS

Postal invitations were sent to a random sample of 2000 17-year-old to 18-year-old women registered with a general practitioner in two pilot areas in England. Recipients were randomised to receive either a self-sampling kit (n=1000), a self-sampling kit and offer of £5 voucher on return of sample (n=500) or a self-sampling kit on request (n=500). Participants returned a questionnaire and self-taken vulvovaginal swab sample for unlinked anonymous Chlamydia trachomatis testing. Non-responders were sent a reminder letter 3 weeks after initial invitation. We calculated the participation rate (number of samples returned/number of invitations sent) and cost per sample returned (including cost of consumables and postage) in each group.

RESULTS

A total of 155/2000 (7.8%) samples were returned with consent for testing. Participation rates varied by invitation group: 7.8% in the group who were provided with a self-sampling kit, 14% in the group who were also offered a voucher and 1.0% in the group who were not sent a kit. The cost per sample received was lowest (£36) in the group who were offered both a kit and a voucher.

CONCLUSIONS

The piloted survey methodology achieved low participation rates. This approach is not suitable for population-based monitoring of chlamydia prevalence among young women in England.

STUDY REGISTRATION NUMBER

(UKCRN ID 10913).

Home sampling for sexually transmitted infections and HIV in men who have sex with men: a prospective observational study

To determine uptake of home sampling kit (HSK) for STI/HIV compared to clinic-based testing, whether the availability of HSK would increase STI testing rates amongst HIV infected MSM, and those attending a community-based HIV testing clinic compared to historical control. Prospective observational study in three facilities providing STI/HIV testing services in Brighton, UK was conducted. Adult MSM attending/contacting a GUM clinic requesting an STI screen (group 1), HIV infected MSM attending routine outpatient clinic (group 2), and MSM attending a community-based rapid HIV testing service (group 3) were eligible. Participants were required to have no symptomatology consistent with STI and known to be immune to hepatitis A and B (group 1). Eligible men were offered a HSK to obtain self-collected specimens as an alternative to routine testing. HSK uptake compared to conventional clinic-based STI/HIV testing in group 1, increase in STI testing rates due to availability of HSK compared to historical controls in group 2 and 3, and HSK return rates in all settings were calculated. Among the 128 eligible men in group 1, HSK acceptance was higher (62.5% (95% CI: 53.5–70.9)) compared to GUM clinic-based testing (37.5% (95% CI: 29.1–46.5)), (p = 0.0004). Two thirds of eligible MSM offered an HSK in all three groups accepted it, but HSK return rates varied (highest in group 1, 77.5%, lowest in group 3, 16%). HSK for HIV testing was acceptable to 81% of men in group 1. Compared to historical controls, availability of HSK increased the proportion of MSM testing for STIs in group 2 but not in group 3. HSK for STI/HIV offers an alternative to conventional clinic-based testing for MSM seeking STI screening. It significantly increases STI testing uptake in HIV infected MSM. HSK could be considered as an adjunct to clinic-based services to further improve STI/HIV testing in MSM.

Dynamic contrast-enhanced perfusion processing for neuroradiologists: model-dependent analysis may not be necessary for determining recurrent high-grade glioma versus treatment effect

BACKGROUND AND PURPOSE

Dynamic contrast-enhanced perfusion MR imaging has proved useful in determining whether a contrast-enhancing lesion is secondary to recurrent glial tumor or is treatment-related. In this article, we explore the best method for dynamic contrast-enhanced data analysis.

MATERIALS AND METHODS

We retrospectively reviewed 24 patients who met the following conditions: 1) had at least an initial treatment of a glioma, 2) underwent a half-dose contrast agent (0.05-mmol/kg) diagnostic-quality dynamic contrast-enhanced perfusion study for an enhancing lesion, and 3) had a diagnosis by pathology within 30 days of imaging. The dynamic contrast-enhanced data were processed by using model-dependent analysis (nordicICE) using a 2-compartment model and model-independent signal intensity with time. Multiple methods of determining the vascular input function and numerous perfusion parameters were tested in comparison with a pathologic diagnosis.

RESULTS

The best accuracy (88%) with good correlation compared with pathology (P = .005) was obtained by using a novel, model-independent signal-intensity measurement derived from a brief integration beginning after the initial washout and by using the vascular input function from the superior sagittal sinus for normalization. Modeled parameters, such as mean endothelial transfer constant > 0.05 minutes(-1), correlated (P = .002) but did not reach a diagnostic accuracy equivalent to the model-independent parameter.

CONCLUSIONS

A novel model-independent dynamic contrast-enhanced analysis method showed diagnostic equivalency to more complex model-dependent methods. Having a brief integration after the first pass of contrast may diminish the effects of partial volume macroscopic vessels and slow progressive enhancement characteristic of necrosis. The simple modeling is technique- and observer-dependent but is less time-consuming.

Microscopy outperformed in a comparison of five methods for detecting Trichomonas vaginalis in symptomatic women

In the UK, despite its low sensitivity, wet mount microscopy is often the only method of detecting Trichomonas vaginalis infection. A study was conducted in symptomatic women to compare the performance of five methods for detecting T. vaginalis: an in-house polymerase chain reaction (PCR); Aptima T. vaginalis kit; OSOM ®Trichomonas Rapid Test; culture and microscopy. Symptomatic women underwent routine testing; microscopy and further swabs were taken for molecular testing, OSOM and culture. A true positive was defined as a sample that was positive for T. vaginalis by two or more different methods. Two hundred and forty-six women were recruited: 24 patients were positive for T. vaginalis by two or more different methods. Of these 24 patients, 21 patients were detected by real-time PCR (sensitivity 88%); 22 patients were detected by the Aptima T. vaginalis kit (sensitivity 92%); 22 patients were detected by OSOM (sensitivity 92%); nine were detected by wet mount microscopy (sensitivity 38%); and 21 were detected by culture (sensitivity 88%). Two patients were positive by just one method and were not considered true positives. All the other detection methods had a sensitivity to detect T. vaginalis that was significantly greater than wet mount microscopy, highlighting the number of cases that are routinely missed even in symptomatic women if microscopy is the only diagnostic method available.

Clinical predictors of rectal lymphogranuloma venereum infection: results from a multicentre case-control study in the U.K

Objective

Since 2003, over 2000 cases of lymphogranuloma venereum (LGV) have been diagnosed in the UK in men who have sex with men (MSM). Most cases present with proctitis, but there are limited data on how to differentiate clinically between LGV and other pathology. We analysed the clinical presentations of rectal LGV in MSM to identify clinical characteristics predictive of LGV proctitis and produced a clinical prediction model.

Design

A prospective multicentre case–control study was conducted at six UK hospitals from 2008 to 2010. Cases of rectal LGV were compared with controls with rectal symptoms but without LGV.

Methods

Data from 98 LGV cases and 81 controls were collected from patients and clinicians using computer-assisted self-interviews and clinical report forms. Univariate and multivariate logistic regression was used to compare symptoms and signs. Clinical prediction models for LGV were compared using receiver operating curves.

Results

Tenesmus, constipation, anal discharge and weight loss were significantly more common in cases than controls. In multivariate analysis, tenesmus and constipation alone were suggestive of LGV (OR 2.98, 95% CI 0.99 to 8.98 and 2.87, 95% CI 1.01 to 8.15, respectively) and that tenesmus alone or in combination with constipation was a significant predictor of LGV (OR 6.97, 95% CI 2.71 to 17.92). The best clinical prediction was having one or more of tenesmus, constipation and exudate on proctoscopy, with a sensitivity of 77% and specificity of 65%.

Conclusions

This study indicates that tenesmus alone or in combination with constipation makes a diagnosis of LGV in MSM presenting with rectal symptoms more likely.

Risk factors for rectal lymphogranuloma venereum in gay men: results of a multicentre case-control study in the U.K

Objective

To identify risk factors for rectal lymphogranuloma venereum (rLGV) in men who have sex with men (MSM).

Design

A case-control study at 6 UK hospitals compared MSM with rLGV (cases) with rLGV-negative controls: MSM without potential rLGV symptoms (CGa) and separately, MSM with such symptoms (CGs).

Methods

Between 2008 and 2010, there were 90 rLGV cases, 74 CGa and 69 CGs recruited. Lifestyles and sexual behaviours in the previous 3 months were reported using internet-based computer-assisted self-interviews. Logistic regression was used to investigate factors associated with rLGV.

Results

Cases were significantly more likely to be HIV-positive (89%) compared with CGa (46%) and CGs (64%). Independent behavioural risks for rLGV were: unprotected receptive anal intercourse (adjusted OR (AOR)10.7, 95% CI 3.5 to 32.8), fisting another (AOR=6.7, CI 1.8 to 25.3), sex under the influence of gamma-hydroxybutyrate (AOR=3.1, CI 1.3 to 7.4) and anonymous sexual contacts (AOR=2.7, CI 1.2 to 6.3), compared with CGa; unprotected insertive anal intercourse (AOR=4.7, CI 2.0 to 10.9) and rectal douching (AOR=2.9 CI 1.3 to 6.6), compared with CGs. An incubation period from exposure to symptoms of 30 days was indicated.

Conclusions

Unprotected receptive anal intercourse is a key risk factor for rectal LGV with the likelihood that rectal-to-rectal transmission is facilitated where insertive anal sex also occurs. The association between HIV and rLGV appears linked to HIV-positive men seeking unprotected sex with others with the same HIV status, sexual and drug interests. Such men should be targeted for frequent STI screening and interventions to minimise associated risks.

The European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP)--a sentinel approach in the European Union (EU)/European Economic Area (EEA)

Antimicrobial resistance in Neisseria gonorrhoeae is monitored in the European Union/European Economic Area through the European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) coordinated by the European Centre for Disease Prevention and Control. Euro-GASP includes a sentinel surveillance programme which aims to detect in a timely manner changes in resistance patterns and inform treatment guidelines. The programme aims to test a representative number of isolates from each European Union/European Economic Area member state per year for a range of therapeutically relevant antimicrobials through a biannual hybrid centralised/decentralised system. Testing is supported by an External Quality Assurance programme and a laboratory training programme. Participation in the programme has increased to 21 countries in 2012. Euro-GASP has been able to detect the rapid spread of isolates with decreased susceptibility to cefixime across Europe in 2010 and 2011. Results from the programme have informed changes in European treatment guidelines for gonorrhoea and led to the development of the 'Response plan to control and manage the threat of multidrug resistant gonorrhoea in Europe'. Future challenges for Euro-GASP include supporting countries to participate in Euro-GASP through decentralised testing, improving timeliness and epidemiological data quality, and increasing participation from Eastern Europe.

Characteristics of LGV repeaters: analysis of LGV surveillance data

Objectives

A number of individuals have acquired lymphogranuloma venereum (LGV) infection multiple times since its re-emergence. We describe the characteristics of reinfections and those who acquire them.

Methods

The LGV Enhanced Surveillance system collected detailed information on LGV episodes in the UK from 2004 to 2010. Using logistic regression we compared the baseline characteristics of men who have sex with men (MSM) who had a repeat LGV episode (‘repeaters’) to MSM with a single reported episode (‘non-repeaters’).

Results

There were 66 individuals among the 1281 MSM (5.2%) with LGV episode who had a recorded reinfection during the data collection period. Those who acquired LGV reinfection were more likely to be HIV positive (97% vs 79%), visit a clinic in London (OR 2.0, 95% CI 1.1 to 3.8), and have hepatitis C (OR 2.2, 95% CI 1.1 to 4.6) or concurrent gonorrhoea (OR 2.2, 95% CI 1.2 to 3.8) on their first recorded LGV episode. Repeaters reported higher levels of unprotected sex, but behavioural variables were not significantly different between repeaters and non-repeaters.

Conclusions

Among LGV repeaters, risk behaviour alone did not explain subsequent reinfection. LGV repeaters have a high level of other sexually transmitted infections (STIs) which may be linked to their central position in the sexual network that contributes to their heightened risk of STI acquisition. Given the low prevalence of LGV in the general MSM population, momentary increases in incidence in subsets of the population may be an important factor for LGV risk where the overall level of sexual risk behaviour is higher. Validating this would require research into sexual network structures.

Testing for sexually transmitted infections in a population-based sexual health survey: development of an acceptable ethical approach

Population-based research is enhanced by biological measures, but biological sampling raises complex ethical issues. The third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3) will estimate the population prevalence of five sexually transmitted infections (STIs) (Chlamydia trachomatis, Neisseria gonorrhoeae, human papillomavirus (HPV), HIV and Mycoplasma genitalium) in a probability sample aged 16-44 years. The present work describes the development of an ethical approach to urine testing for STIs, including the process of reaching consensus on whether to return results. The following issues were considered: (1) testing for some STIs that are treatable and for which appropriate settings to obtain free testing and advice are widely available (Natsal-3 provides all respondents with STI and healthcare access information), (2) limits on test accuracy and timeliness imposed by survey conditions and sample type, (3) testing for some STIs with unknown clinical and public health implications, (4) how a uniform approach is easier to explain and understand, (5) practical difficulties in returning results and cost efficiency, such as enabling wider STI testing by not returning results. The agreed approach, to perform voluntary anonymous testing with specific consent for five STIs without returning results, was approved by stakeholders and a research ethics committee. Overall, this was acceptable to respondents in developmental piloting; 61% (68 of 111) of respondents agreed to provide a sample. The experiences reported here may inform the ethical decision making of researchers, research ethics committees and funders considering population-based biological sampling.

A laboratory-based evaluation of the BioStar Optical ImmunoAssay point-of-care test for diagnosing Neisseria gonorrhoeae infection

The development of gonococcal point-of-care tests (POCTs) has been challenging due to the relatively monomorphic nature of the Neisseria genus. The BioStar Optical ImmunoAssay (OIA) POCT for diagnosing Neisseria gonorrhoeae infection detects a specific epitope on the L7/L12 ribosomal protein, which reduces cross-reactivity with other neisseriae, and produces a highly specific test. A laboratory-based evaluation of this POCT was performed to determine its analytical sensitivity and specificity. A panel of N. gonorrhoeae (n=158) and non-gonococcal Neisseria (n=62) isolates were examined. The OIA GC POCT positively reacted with 99.4% of N. gonorrhoeae isolates and produced no reaction with 88.7% of non-gonococcal Neisseria isolates. It cross-reacted with six strains of N. meningitidis and one non-speciated Neisseria sp., but failed to produce a positive result with one isolate of N. gonorrhoeae. The OIA GC POCT required a bacterial suspension of ~6.4×10(5) c.f.u. N. gonorrhoeae ml(-1) and ~6.2×10(6) c.f.u. N. meningitidis ml(-1) to produce a reactive result. The OIA POCT detected the majority of N. gonorrhoeae (99.4%) isolates examined.

Still no evidence of new variant Chlamydia trachomatis in England and Wales

Background: New variant Chlamydia trachomatis (nvCT) remains an important public health concern and in 2008 four cases of nvCT were reported in Scotland. The present study set out to determine whether nvCT was present in England and Wales. Methods: 1054 clinical specimens, which had been confirmed as chlamydia positive (using an nvCT unaffected platform) at nine different diagnostic laboratories throughout England and Wales, were examined for the presence of the 377 bp nvCT deletion. Results: 92% (968/1054) of specimens examined were confirmed as wild-type C. trachomatis. The remaining 86 specimens were found to be untypeable, which was probably due to low levels of DNA. No nvCT specimens were identified. Conclusions: There is currently no evidence that nvCT is present in England and Wales; however, laboratories using nvCT-affected platform should remain vigilant.