Diagnosis of chlamydial infection by direct enzyme-linked immunoassay and polymerase chain reaction in patients with acute follicular conjunctivitis

Ten-year review of a shared care approach in the management of ocular chlamydia trachomatis infections

INTRODUCTION

Since 2007, the ocular 4:1 multiplex PCR assay in NHS Greater Glasgow and Clyde includes Chlamydia trachomatis (ocular chlamydia (OC)) testing. OC can be identified following routine 'viral' ophthalmic testing, including in asymptomatic patients. A published audit from 2008 identified only 25% of our OC patients attended and completed sexual health management, particularly when ophthalmologists initiated treatment. We subsequently created a shared care network between ophthalmology, virology and sexual health (including a designated sexual health advisor) to address these clinical issues.

METHODS

A 10-year retrospective service review audit from January 2010 to December 2019 was performed to evaluate this approach.

RESULTS

A total of 86 patients were identified (49 males (57%), median age 23 years (range 16-77)). Ophthalmologists initiated treatment for 37 patients (43%) prior to onward sexual health referral. Of this group, 5 (13.5%) received sub-optimal treatments, and 15 (40.5%) subsequently failed to attend sexual health services for partner notification. Of the 49 (57%) patients who attended sexual health, 25 (51%) had genital chlamydia co-infection, and 98% received adequate systemic treatment. All were offered full sexual health screening and 46 (93.9%) completed partner notification.

CONCLUSIONS

This shared care approach more than doubled the proportion of OC patients attending sexual health services over this 10-year period (previously 25%, now 57%). Ophthalmologists could defer treatment to sexual health for more effective OC management; however, challenges remain to address real-world issues of non-attendance, inadequate treatment and incomplete contact tracing. We recommend a multi-disciplinary approach to best manage OC cases identified following ophthalmic testing.

Ultrasensitive SERS aptasensor for the detection of oxytetracycline based on a gold-enhanced nano-assembly

This paper investigated a new detection method of oxytetracycline (OTC) in aquatic products with ultrasensitive detection limit. The method was constructed on the basis of raman hot spot between gold nanoparticles (AuNPs) (13nm and 80nm diameter respectively) linked by an DNA sequence. The DNA sequence combined with the OTC aptamer including its complementary sequence as well as a stem-loop structure. The raman signal molecule (4-MBA) was modified at the surface of 13nm AuNPs. After the exposure of OTC, the aptamer sequence was preferentially combined with OTC and partially dehybridized with its complementary sequence which led the 13nm AuNPs to get more closer to the 80nm AuNPs. The raman intensity was thus increased for the more enhanced hot spot generated. Under the optimal experimental conditions, the SERS signal was positively related to the OTC concentration with a wide working range of 4.60×10^-2-4.60×10²fg/mL and the limit of detection (LOD) was as low as 4.35×10^-3fg/mL. The recovery rates of fishmeal ranged from 91.29-110.98%. The specificity of this method was further examined, and the results showed that the AuNPs based aptasensor was highly selective. This developed ultrasensitive aptamer-based SERS detection platform suggested that it may be a promising strategy for a variety of sensing applications.

One-pot hydrothermal synthesis of luminescent silicon-based nanoparticles for highly specific detection of oxytetracycline via ratiometric fluorescent strategy

Amino groups terminated luminescent SiNPs have been designed for ratiometric visual detection of OTC in vitro and milk samples.

A practical approach to ocular pain for the non-ophthalmologist

Pain involving the eye has numerous etiologies and is a feared challenge of many clinicians. Between a fear of the patient losing vision and a lack of familiarity with the ophthalmic equipment necessary to diagnose the problem, working up eye pain can be a daunting task. While the ophthalmologist can be indispensable in challenging cases of eye pain, this article will help clarify the unique clinical features of each etiology that can help clinicians narrow down the differential and arrive at a diagnosis.

Multiplex PCR testing requires a robust multi-disciplinary strategy to effectively manage identified cases of chlamydial conjunctivitis

Introduction

Implementation of an in-house polymerase chain reaction (PCR) multiplex assay by West of Scotland Specialist Virology Centre to improve sample processing means all viral eye swabs are now routinely tested for Adenovirus, Herpes simplex, Varicella and Chlamydia. Concern was raised regarding subsequent management and sexual health attendance for Chlamydia-positive patients identified in eye casualty.

Methods

A retrospective review of virology results identified 76 Chlamydia-positive patients from 1914 eye swabs (4%) from May 2007 to April 2008. Of these results, 12 originated from Glasgow eye casualty and available clinical notes were cross-referenced with the sexual health network (Sandyford).

Results

Identified issues included no documentation of implications of testing, poor communication of positive results and poor referral pathways to sexual health for assessment; all leading to inadequate management. A shared care network was created to address these issues. A designated sexual health advisor was identified to improve sexual health referral, specialist assessment, standardised management and contact tracing. Re-audit showed more consistent follow-up.

Conclusion

New PCR technology has resulted in a shared care approach to address corresponding implications of testing. Effective communication with a structured protocol and a central point of contact has improved follow-up and ensures appropriate best practice management of chlamydial conjunctivitis.

Pain of ocular and periocular origin

Most diseases of the eye and periocular regions that cause blindness are relatively painless. Headache pain of ocular and periocular origin represent a special challenge to the clinician. For patients with ocular and periocular pain that is unrelated to primary eye disease, identification and treatment of the painful condition usually become the responsibility of the clinician.

The use of polymerase chain reaction assay versus conventional methods in detecting neonatal chlamydial conjunctivitis

PURPOSE

To compare the performance of polymerase chain reaction versus conventional methods (cell culture and direct immunofluorescent assay) in diagnosing neonatal chlamydial conjunctivitis and their correlations to the severity of conjunctivitis.

METHODS

Consecutive cases of neonatal conjunctivitis were recruited over a year. Both eyes were clinically graded according to the severity of conjunctivitis and investigated using the three aforementioned chlamydial tests. Neonatal chlamydial conjunctivitis was assumed if one of these three tests was positive and there was clinical improvement after treatment. Sensitivity and specificity of each of the tests were analyzed.

RESULTS

Three hundred sixty-eight sets of chlamydial tests were done for 184 neonates. The percentage of positive results was 93.8% and 71.9% for polymerase chain reaction and conventional methods, respectively. Using positive results in either cell culture or direct immunofluorescent assay as a standard to diagnose neonatal chlamydial conjunctivitis, the sensitivity and specificity of polymerase chain reaction were 92.0% and 97.7%, respectively. If we used polymerase chain reaction as a standard, the sensitivity and specificity of cell culture were 73.3% and 99.7%, respectively. A discrepancy was noted in the number of positive results between polymerase chain reaction and conventional methods in milder disease.

CONCLUSIONS

Polymerase chain reaction might have a higher sensitivity and similar specificity in diagnosing neonatal chlamydial conjunctivitis compared to conventional methods, and it has an additional advantage as a diagnostic tool in mild disease.

Follicular conjunctivitis caused by Chlamydia trachomatis in an infant Saharan population: molecular and clinical diagnosis

AIMS

To ascertain the prevalence of acute trachoma as a supposed endemic disease among infants in the Saharan refugee camps of Tindouf (Algeria) and to evaluate the efficacy of treatment with a single dose of azithromycin.

METHODS

527 children aged between 3 and 17 were evaluated in the camp schools in October 2001. All the children were clinically and microbiologically examined, including slit lamp checks of anterior segment and two conjunctival swabs, one for the detection of membrane lipopolysaccharide by quick immunoassay test Clearview Chlamydia MF and the other for the detection of specific DNA by chlamydia plasmid specific polymerase chain reaction (PCR) assay. After examination, a single dose of azithromycin was administered to each child. One month later samples from positive children and 12 random negative children by the first PCR were taken to perform a new PCR assay.

RESULTS

Chlamydia trachomatis was suspected in 2.47% of the children, papillary hypertrophy being the most frequently seen clinical sign. Scarring changes secondary to trachoma were detected in 11.7% of the children. Only four cases (0.8%) were positive to the immunoassay test and 12 cases (2.27%) were positive by PCR. After treatment a second PCR was performed on positive children and they were negative of chlamydia DNA amplification. However, one child who was negative and received the treatment was positive in the second PCR assay.

CONCLUSION

Acute trachoma prevalence is much lower than expected among infants in this Saharan population. The possible reasons could be the recent improvements in hygiene and health care. Cicatricial trachoma is more frequent. The Clearview immunoassay test has very low sensitivity in the detection of this disease. A single dose of azithromycin is sufficient to treat chlamydial conjunctivitis. However, a programme of improvement in hygiene and health care is necessary to prevent re-infection.

Polymerase chain reaction based detection of fungi in infected corneas

AIMS

To evaluate a polymerase chain reaction (PCR) based assay to detect fungi in scrapings from infected corneas.

METHODS

A PCR assay was developed to amplify a portion of the fungal 18S ribosome gene. Corneal scrapings from 30 patients with presumed infectious keratitis were evaluated using this assay, as well as by standard microbiological techniques, and the results were compared. Conjunctival swabs from each patient's healthy, fellow eye were also evaluated by PCR.

RESULTS

PCR and fungal culture results matched (were both positive or both negative for fungi) in 22 (74%) of 30 scrapings from infected corneas. Three (10%) of 30 samples were PCR positive but fungal culture negative; two of these appeared clinically to represent fungal infections, and the third was clinically indeterminate. Four (13%) scrapings were positive by PCR but also by bacterial and not fungal culture. One specimen (3%) was PCR negative but fungal culture positive. Of the conjunctival swabs from each patient's healthy fellow eye, five (17%) of 30 were positive by PCR, and the opposite, infected eye of all five of these harboured a fungal infection.

CONCLUSIONS

PCR is promising as a means to diagnose fungal keratitis and offers some advantages over culture methods, including rapid analysis and the ability to analyse specimens far from where they are collected.