Diagnosis of viral and chlamydial keratoconjunctivitis: which laboratory test?

Molecular, Epidemiological and Clinical Assessment of Adenoviral Keratoconjunctivitis in Egypt: Institutional Study

PURPOSE

To evaluate the frequency of Human adenovirus (HAdV) and its serotypes in keratoconjunctivitis patients who attended the outpatient clinics of Mansoura Ophthalmic Center, Egypt.

METHODS

Conjunctival secretions and corneal scrapings were collected from patients complaining of clinically diagnosed viral keratoconjunctivitis. The molecular method for HAdV detection was performed by polymerase chain reaction (PCR) followed by restriction enzymes (REA) determination of serotypes for hexone gene.

RESULTS

HAdV infection was detected in 38% of samples. There were 4 serotypes of Human adenovirus species D (HAdV-D) isolated (4, 8, 37, 3), where HAdV-D8 was the most dominant. Contact with infected patient, follicular conjunctivitis and subepithelial corneal infiltrates are useful features for clinical diagnosis of adenoviral conjunctivitis.

CONCLUSION

HAdV was significant etiological factor of acute follicular conjunctivitis. Accurate diagnosis of adenoviral conjunctivitis is essential for appropriate management, reducing permanent visual impairment and to limit the transmission of the virus within the community.

Conjunctivitis: A Primer on Conjunctival Biopsy and Approach to Histopathologic Diagnosis

Conjunctivitis, or inflammation of the mucosal covering the anterior third of sclera and inner eyelid, is a common clinical condition of varied causation. Most cases are self-limited due to infection or allergy and rarely necessitate biopsy. Inflammation of the conjunctiva, however, is one of the most common principal histopathologic diagnoses rendered when the tissue is biopsied. In the context of conjunctivitis, biopsy is usually performed when inflammation is chronic and recalcitrant to therapy, has clinically atypical features, or requires an etiologic diagnosis when one cannot be reached through other laboratory methods. The exclusion of ocular surface neoplasia in a chronically inflamed conjunctiva is a common justification for biopsy. When inflammation is the principal histopathology finding, it is desirable-whenever feasible-to establish the cause. This brief review provides a guide in how histologic findings of an inflamed conjunctiva can direct the clinical evaluation towards an etiologic diagnosis.

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.

A systematic review on advances in diagnostics for herpes simplex keratitis

Herpes simplex keratitis (HSK) is a significant cause of vision impairment worldwide. Currently, there are no set diagnostic criteria, and popular diagnostic methods, including clinical examination of the eye via slit lamp examination, could lead to false-negatives and misdiagnoses. Molecular testing with polymerase chain reaction (PCR) may lack concordance with clinical findings, posing a great challenge to ophthalmologists. We evaluate recent studies on techniques for the diagnosis of HSK. We included a total of 23 studies published between 2010 and 2020 in English on diagnostic techniques, including in vivo confocal microscopy, polymerase PCR testing, protein detection in tear film with enzyme-linked immunosorbent assay, and various other protein assays. Although PCR has been widely used as one of the current diagnostic methods for HSK, most studies evaluated its efficacy after including alterations to its normal protocol. Tear sample analysis was performed using multiple tools, although corneal scrapings demonstrated a higher positive detection rate. Diagnostic tools identified were able to detect HSK with varying accuracy. Newer diagnostic techniques like multiplex dot hybridization assay and immunochromatographic assays may be considered as the point-of-care preliminary diagnostic tools. More reliable results may be generated by developing a standardized diagnostic protocol.

Adenovirus: Epidemiology, Global Spread of Novel Serotypes, and Advances in Treatment and Prevention

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The disease is more severe and dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 50 serotypes of AdV have been identified. Different serotypes display different tissue tropisms that correlate with clinical manifestations of infection. The predominant serotypes circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been conducted. Cidofovir is the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States, but currently are not available to civilians.

Chlamydia and ocular adnexal lymphomas: An Indian experience

CHLAMYDIA AND OCULAR ADNEXAL LYMPHOMAS

AN INDIAN EXPERIENCE: Ocular adnexal lymphomas (OALs) are a heterogeneous group of malignancies, majority being extranodal mucosa-associated lymphoid tissue (MALT) type. Different geographical regions have reported association of Chlamydia with OALs (MALT type). In India, role of Chlamydia in OALs remains unexplored. The aim of this study was to detect Chlamydia and to correlate with clinicopathological features of OALs in India. The clinicopathological features of 41 OAL cases were studied prospectively. Chlamydia DNA was detected by genus specific PCR amplifying major outer membrane protein (MOMP) gene followed by DNA sequencing. Chlamydia immunoexpression was evaluated by immunofluorescence and immunohistochemistry. The results were correlated with clinicopathological features including follow-up and survival. Chlamydia genome was detected in 3/41 (7.3%) OAL cases by PCR. Direct sequencing revealed C. trachomatis in 3 positive cases. Immunofluorescence and immunohistochemistry showed Chlamydia antigen in 5/41 and 1/41 cases respectively. Immunofluorescence demonstrated higher sensitivity than immunohistochemistry. A significant association was observed between Chlamydia positivity and orbital location (P=0.05). Follow-up revealed relapse in 2 Chlamydia positive cases (P=0.056). Our results demonstrate for the first time presence of C. trachomatis genome in 7.3% OAL cases in India. As no other reports are documented, more detailed studies from different regions within India are needed to explore status of Chlamydia in OALs.

Real-time polymerase chain reaction for the diagnosis of necrotizing herpes stromal keratitis

AIM

To design, optimize and validate a rapid, internally controlled real-time polymerase chain reaction (RT-PCR) test for herpes simplex virus (HSV) in the diagnosis of necrotizing herpes stromal keratitis.

METHODS

Tears alone or together with corneal epithelium scrapings from 30 patients (30 eyes) suspected of necrotizing herpes stromal keratitis were tested for HSV DNA by RT-PCR. The samples were collected during the first visit and then on the subsequent 7, 14, 28, 42, and 56d. The symptoms of the patients were scored before treatment to determine the correlation between HSV concentration in the corneal epithelium scrapings and clinical scores.

RESULTS

The positive rate (46.4%) in the corneal epithelium group before the therapy was significantly higher than that (13.3%) in the tears group (P=0.006). There were 13 positive HSV patients before the therapy, the concentration of HSV DNA in corneal epithelium scrapings group was significantly higher than that in the tears group (paired t-test, P=0.0397). Multilevel mixed-effects model analysis showed that the difference between the corneal epithelium scrapings group and the tears group was statistically significant (P=0.0049). The Spearman rank correlation analysis indicated a positive correlation between the HSV concentration in the corneal epithelium scrapings and clinical scores before the treatment (r=0.844, P<0.0001).

CONCLUSION

RT-PCR appears to be a powerful molecular tool for the diagnosis of necrotizing herpes stromal keratitis.

Evaluation of direct immunofluorescence assay and cytological examination in comparison to polymerase chain reaction of conjunctival swabs in patients with adult inclusion conjunctivitis

PURPOSE

To evaluate PCR, direct immunofluorescence assay (DIA) and cytological test of conjunctival swabs for the diagnosis of adult follicular conjunctivitis (AFC).

METHODS

Eighty-three adult patients with chronic conjunctivitis and sixteen healthy individuals were included. Conjunctival scrapings underwent PCR, DIA and cytological analysis. Exams were repeated two weeks after treatment application. Sensitivity, specificity and agreement rate with PCR of DIA and Cytology were evaluated and correlated with clinical symptoms/signs.

RESULTS

Cytology test was more sensitive than DIA and presented an acceptable agreement with PCR (K=0.44) in treatment-naïve patients, concerning especially the combination of both conventional exams (K = 0.77). Inferior diagnostic performance of was detected post-treatment, considering the combination as well (K=0.40). Negative post-treatment PCR correlated well with significant relief of symptoms/signs.

CONCLUSION

Combination of Cytology and DIA seems to be a useful diagnostic option for treatment naïve AFC patients. However, PCR remains the most reliable test for post-treatment evaluation.

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.

Acute conjunctivitis: truth and misconceptions

OBJECTIVE

Acute conjunctivitis is an extremely common condition and can be associated with significant morbidity and economic burden. Despite this, considerable controversy exists pertaining to the prevalence, diagnosis, management, and treatment of the condition. A panel of ophthalmology experts was assembled to review and discuss the current evidence based literature as it pertains to each of these persistent controversies.

METHODS AND SCOPE

An acute conjunctivitis round table symposium was convened at the American Academy of Ophthalmology meeting in Atlanta, November 2008. The expert panelists consisted of four academic ophthalmologists in the field of cornea and external disease, whose discussion was informed by an English language literature survey carried out on the PubMed database for the period of January 1972 to October 2008. A narrative summary was generated from the literature review and direct transcription of this event, from which this Review article was developed.

FINDINGS AND CONCLUSIONS

Considerable light has been shed on acute microbial conjunctivitis and especially those cases caused by adenovirus. Many of the myths that have perpetuated for years have been debunked by emerging evidence. The advent and the implementation of better diagnostic tools and anti-viral medications will help clinicians to improve their diagnostic accuracy, improve management and treatment decisions, and ultimately benefit patients while saving overall healthcare costs.

Corneal superinfection in acute viral conjunctivitis in young children

Two children suffered from corneal superinfection following acute viral keratoconjunctivitis. Group A beta-hemolytic streptococci were isolated in one child and cultures were negative in the other child. The corneal ulcers resolved with prompt antibiotic therapy, but both patients developed amblyopia. Visual outcome following corneal superinfection in acute viral conjunctivitis may be poor when it occurs in young children.

A community-derived outbreak of adenovirus type 3 in children in Taiwan between 2004 and 2005

An outbreak of respiratory adenovirus infection in children was observed in northern Taiwan between November 2004 and February 2005. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to determine the serotype(s) of 172 adenovirus isolates in the outbreak period, we found that adenovirus type 3 (Ad3) was the predominant type (87.2%), followed by Ad2 (6.4%), Ad1 (4.1%), Ad7 (1.2%), Ad4 (0.6%), and Ad5 (0.6%). The genotype of Ad3 was analyzed for 15 isolates from the outbreak period by RFLP of the full-length genome. All these isolates belonged to genotype Ad3a2. Compared with the Ad3-infected patients in the baseline period, a significantly higher proportion of Ad3-infected patients in the outbreak period had severe infections (58.0% vs. 40.2%, P = 0.01), which included bronchopneumonia (28.7%), exudative tonsillitis (24.1%), and tonsillitis (16.1%). Moreover, patients with severe infections were significantly younger than those without (4.10 vs. 8.15 years, P < 0.001). In summary, our study demonstrated that Ad3 was the predominant serotype responsible for the respiratory adenovirus outbreak in northern Taiwan during 2004-2005 and was associated with severe infections in the outbreak period.

Rapid detection of oculopathogenic adenovirus in conjunctivitis

Ocular adenovirus (Ad) infections occur throughout the world in both sporadic and epidemic forms. Accurate laboratory diagnosis of Ad in conjunctival samples is always valuable. The present study was carried out to explore the presence of Ad as a causative agent in clinically suspected viral conjunctivitis and to compare the performance of conventional virus isolation on cell cultures, direct detection of Ad antigens in conjunctival cells by a direct fluorescence assay, Ad DNA detection by polymerase chain reaction (PCR), and specific IgM measurement by ELISA. Samples included scrapes from conjunctiva. Scrapes were subjected to study by direct immunofluorescence stain, culture on the Hep-2 cell line, and PCR for Ad detection. Blood samples were also taken and subjected to study for specific anti-Ad IgM determination. The culture for Ad was positive in 77.8%, direct antigen detection by fluorescent stain was positive in 72.2%, PCR was positive in 83.3%, and serology was positive in 88.9% of patients. Both determination of antibody IgM and PCR correctly identified a larger group of patients compared to cell culture. The most sensitive and specific method for diagnosis of Ad compared to culture was PCR (100%), followed by IgM detection (92.9%) then direct antigen detection by fluorescent stain (85.8%). From this study, we conclude that Ad is a common pathogen in sporadic cases of conjunctivitis. Screening of adenoviral conjunctivitis is possible by using specific IgM due to its high sensitivity. A confirmatory test can be done by PCR for diagnosis of Ad, as it is a rapid, specific, and accurate method.

Microbiologic investigations for head and neck infections

A variety of methods, including direct examination of stained smears, antigen detection, routine and special cultures, and histopathologic evaluation are available for investigation of head and neck infections. Newer rapid molecular techniques with increased sensitivity and specificity are becoming available at many centers. Evaluation of specific causes in head and neck infections is complicated by the tendency for polymicrobial infections, difficulty in obtaining adequate specimens, and the presence of a diverse endogenous microflora at various mucosal sites that also can include true pathogens. These aspects of laboratory investigation for head and neck infections are reviewed in this article.

The prevalence of adenoviral conjunctivitis at the Wills Eye Hospital Emergency Room

OBJECTIVE

The aim of this study was to evaluate the prevalence of adenoviral conjunctivitis by analyzing data from a prospective clinical study of 50 consecutive patients presenting to the Wills Eye Hospital Emergency Room (WEH ER) with a clinical diagnosis of infectious conjunctivitis from July 2003 to October 2003.

METHODS

The polymerase chain reaction (PCR) was used to evaluate all cases of clinically diagnosed infectious conjunctivitis. Based on the laboratory findings, the prevalence of adenovirus was determined.

RESULTS

Of the 50 consecutive patients with acute infectious conjunctivitis, 31 patients were PCR positive for adenovirus.

CONCLUSIONS

The prevalence of adenoviral conjunctivitis was found by PCR to represent 62% of all patients presenting with a clinical diagnosis of infectious conjunctivitis from July 2003 to October 2003.

Chlamydienerkrankungen des Auges – eine kurze Übersicht

In this short review, new data on the taxonomy of Chlamydia and the association of these pathogens with various ocular diseases are presented. Clinical diagnosis and laboratory tests for ocular C. trachomatis infection are discussed. The actual therapy consists in oral azithromycin.

[Identification of adenoviruses serotypes implicated in haemorrhagic conjunctivitis in Tunisia]

Human adenoviruses (ADV) are distributed worldwide; they are associated with a variety of diseases. Some ADV can be implicated in large epidemics of conjunctivitis, gastroenteritis and respiratory infections. Classical diagnosis of ADV infections is based on virus isolation on cell culture and identification of the serotype by neutralization test or hemagglutination inhibition assay. However, these methods have a lack of rapidity that makes them impractical in clinical situations. With the advent of PCR, the diagnosis of ADV was improved. In this work, we have used molecular techniques for the identification of ADV serotypes implicated in conjunctivitis in Tunisia. A total of 199 conjunctival swabs received between October 2000 and May 2005 were investigated. Serotype identification was performed using a PCR followed by restriction enzyme analysis in the hexon gene. Typing by sequencing of the PCR product was used to confirm the serotype identification. Among the 199 tested clinical specimens, 24% were positive for ADV. Two different profiles were observed: one predominant corresponding to the majority of the detected ADV; this profile is in favour of two distinct serotypes, ADV37 or ADV8; the second profile was specific of ADV4 and was found in one case observed in 2005. Sequencing confirmed two serotypes: ADV8 with an endemoepidemically circulation in our country and ADV4 that appeared sporadic. The present work showed the importance of molecular techniques not only for ADV detection but also for identification of the circulating serotypes. These techniques are practical and interesting mainly for the rapid virological investigation during epidemics.

Evaluation of herpes simplex detection in corneal scrapings by three molecular methods

Herpes simplex virus (HSV)-1 keratitis (HSK) is a sight-threatening ocular infection with worldwide occurrence. A prompt laboratory diagnosis is often very useful. The purpose of this study was to evaluate molecular methods as rapid diagnostic tools compared with cell culture of HSK. Corneal scrapings from patients with clinically suspected HSK were tested by direct immunofluorescence assay (IFA) for HSV-1 antigen and by polymerase chain reaction (PCR) for HSV-1 DNA, and an attempt for viral isolation was performed on Vero cell line culture. Positive samples by cell culture were 20.8%, whereas PCR was positive in 29.2%, and IFA was positive in 33.3%. IFA had better sensitivity (80%) and negative predictive value (81.8%) than PCR (70% and 76.9%, respectively); however, PCR had better specificity (71.4%) and positive predictive value (63.6%). This indicates that a combination of cell culture, IFA and PCR constitutes the best set of tools for diagnosis of clinically suspected cases of HSK. Documented infection can be further assessed by cell-culture technique or PCR depending laboratory availability.

Chlamydia psittaci is variably associated with ocular adnexal MALT lymphoma in different geographical regions

Infectious agents play a critical role in MALT lymphoma development. Studies from Italy showed Chlamydia psittaci infection in 87% of ocular adnexal MALT lymphomas and complete or partial regression of the lymphoma after C. psittaci eradication in four of nine cases. However, C. psittaci was not demonstrated in ocular adnexal MALT lymphomas from the USA. This study was thus designed to investigate further the role of C. psittaci, and other infectious agents commonly associated with chronic eye disease, in the development of ocular adnexal MALT lymphoma. The presence of C. psittaci, C. trachomatis, C. pneumoniae, herpes simplex virus 1 and 2 (HSV1, HSV2), and adenovirus 8 and 19 (ADV8, ADV19) was assessed separately by polymerase chain reaction in 142 ocular adnexal MALT lymphomas, 53 non-marginal zone lymphomas, and 51 ocular adnexal biopsies without a lymphoproliferative disorder (LPD), from six geographical regions. C. psittaci was detected at similar low frequencies in non-LPD and non-marginal zone lymphoma groups from different geographical regions (0-14%). Overall, the prevalence of C. psittaci was significantly higher in MALT lymphomas (22%) than in non-LPD (10%, p=0.042) and non-marginal zone lymphoma cases (9%, p=0.033). However, the prevalence of C. psittaci infection in MALT lymphoma showed marked variation among the six geographical regions examined, being most frequent in Germany (47%), followed by the East Coast of the USA (35%) and the Netherlands (29%), but relatively low in Italy (13%), the UK (12%), and Southern China (11%). No significant differences in the detection of C. pneumoniae, C. trachomatis, HSV1, HSV2, ADV8, and ADV19 were found between lymphomas and controls from different geographical regions. In conclusion, our results show that C. psittaci, but not C. pneumoniae, C. trachomatis, HSV1, HSV2, ADV8 or ADV19, is associated with ocular adnexal MALT lymphoma and that this association is variable in different geographical areas.

Rapid detection and identification of human adenovirus species by adenoplex, a multiplex PCR-enzyme hybridization assay

Human adenoviruses (AdV) have been implicated in a wide variety of diseases and are ubiquitous in populations worldwide. These agents are of concern particularly in immunocompromised patients, children, and military recruits, resulting in severe disease or death. Clinical diagnosis of AdV is usually achieved through routine viral cell culture, which can take weeks for results. Immunofluorescence and enzyme-linked immunosorbent assay-based techniques are more timely but lack sensitivity. The ability to distinguish between the six different AdV species (A to F) is diagnostically relevant, as infections with specific AdV species are often associated with unique clinical outcomes and epidemiological features. Therefore, we developed a multiplex PCR-enzyme hybridization assay, the Adenoplex, using primers to the fiber gene that can simultaneously detect all six AdV species A through F in a single test. The limit of detection (LOD) based on the viral 50% tissue culture infective dose/ml for AdV A, B, C, D, E, and F was 10(-2), 10(-1), 10(-1), 10(-2), 10(-1), and 10(-2), respectively. Similarly, the LOD for the six DNA controls ranged from 10(2) to 10(3) copies/ml. Twelve common respiratory pathogens were tested with the Adenoplex, and no cross-reactivity was observed. We also validated our assay using clinical specimens spiked with different concentrations of AdV strains of each species type and tested by multiplex PCR and culture. The results demonstrated an overall sensitivity and specificity of Adenoplex of 100%. This assay can be completed in as few as 5 h and provides a rapid, specific, and sensitive method to detect and subtype AdV species A through F.

Epidemic kerato-conjunctivitis--do outbreaks have to be epidemic?

PURPOSE

To study: the epidemiology of an outbreak of adenoviral keratoconjunctivitis in a UK teaching hospital; disease presentation and its effect on clinical diagnostic efficiency; patterns of viral transmission between staff and patients; the effectiveness of infection control procedures in minimising outbreaks.

METHODS

Prospective/retrospective clinical audit and retrospective audit of virological culture results: all viral culture swabs taken during an outbreak of adenoviral keratoconjunctivitis were analysed. The case records of patients whose viral swabs were positive for adenoviral culture were traced. The time for viral cultures to become positive (culture positive time) was calculated. Analysis of the case notes was performed to elucidate (1) the source of infection and (2) the risk factors for acquisition of the infection. Retrospective clinical audit was performed to evaluate the effectiveness of infection control procedures. Adenovirus isolates underwent serotyping.

RESULTS

During the 3-month period of study, there were 38 confirmed cases of adenoviral keratoconjunctivitis. This represented a 217% increase in the number of new cases per 3-month period. The case notes for five patients were untraceable. Of the remaining 33 patients, 21 (63%) had acquired their infection either directly or indirectly from the eye department and 22 (67%) had presented with unilateral disease. The rate of misdiagnosis was higher (9/22=42%) in patients presenting with unilateral disease than those presenting with bilateral disease (2/11=18%). Intradepartmental acquisition of infection was associated with invasive procedures, for example use of diagnostic/therapeutic contact lenses. Culture positive times ranged from 3 to 29 days. The introduction of infection control procedures was associated with a dramatic decrease in the incidence of departmentally acquired cases with no new cases after 2 weeks. Multiple serotypes of adenovirus were involved.

CONCLUSION

Outbreaks of adenoviral keratoconjunctivitis are a serious public health issue concerning ophthalmic departments. This audit study illustrates several important points: (1) how hospital-acquired infection can account for a significant proportion of the cases seen, (2) how multiple types of adenovirus can be involved in a single outbreak, (3) that severe unilateral disease is associated with a higher rate of misdiagnosis; and (4) how standard viral culture techniques may not be satisfactory in confirming/disproving infection when the diagnosis is in doubt. The potential benefit of infection control procedures in minimising this outbreak could not be proven within this audit.

Chlamydial conjunctivitis (in adults), uveitis, and reactive arthritis, including SARA. Sexually acquired reactive arthritis

This chapter deals with Chlamydia -induced ocular and rheumatic diseases of the adult. All of these may follow a primary urogenital infection with Chlamydia trachomatis in genetically predisposed patients. Besides the infection with Chlamydia trachomatis, infections with Chlamydia pneumoniae and Chlamydia psittaci are also discussed as possible causative agents. Chlamydial conjunctivitis is frequently a secondary infection, and the organism is transferred from the urogenital tract to the eye by autoinoculation. Uveitis and reactive arthritis are believed to be triggered - among other infections - by a preceding urogenital infection. Both of them are closely associated with HLA-B27 positivity. The simultaneous occurrence of uveitis and reactive arthritis is termed Reiter's syndrome. We report on clinical characteristics, diagnosis and the role of Chlamydia in the pathogenesis of chlamydial conjunctivitis, uveitis and reactive arthritis as well as on the currently recommended treatment regimens.

Hemorrhagic viral keratoconjunctivitis in Taiwan caused by adenovirus types 19 and 37: applicability of polymerase chain reaction-restriction fragment length polymorphism in detecting adenovirus genotypes

PURPOSE

Acute keratoconjunctivitis with prominent subconjunctival hemorrhage (SCH) is usually perceived by a clinician as acute hemorrhagic conjunctivitis (AHC) associated with enteroviruses; however, SCH can also be an adenoviruses infection. A rapid and sensitive laboratory diagnosis is helpful for differential diagnosis. Therefore, the sensitivity and applicability of polymerase chain reaction (PCR) and reverse transcription (RT)-PCR diagnoses were evaluated for keratoconjunctivitis associated with viral infection.

METHODS

Conjunctival swabs from patients with acute conjunctivitis were tested using a PCR-restriction fragment length polymorphism (PCR-RFLP) for adenovirus detection and RT-PCR for enterovirus detection. The results were compared with those using the culture isolation and neutralization test; also, the clinical findings of the patients were analyzed with special attention to SCH patterns.

RESULTS

Neither coxsackievirus A type 24 variant (CA24v) nor enterovirus type 70 (EV70) was detected in 113 patients with acute conjunctivitis. The positive results of adenovirus (Ad) were 39.9% by the PCR method and 37.1% by culture isolation. For the patients with adenoviral conjunctivitis, 68.1% was owing to Ad37 and 19.2% was owing to Ad19. SCH was present in 51.5% of the positive cases, and 44.7% of the Ad-positive patients had secondary illnesses.

CONCLUSIONS

SCH can be a predominant presentation of Ad19 and Ad37 keratoconjunctivitis and may herald a new stage in the evolution of adenoviruses. PCR and PCR-RFLP are rapid and reliable methods for Ad detection and typing; however, if the amplified genes and restriction enzymes are not properly selected, they may not be able to detect new genotypes of adenoviruses or the evolution of these viruses.

Multiplex PCR: optimization and application in diagnostic virology

PCR has revolutionized the field of infectious disease diagnosis. To overcome the inherent disadvantage of cost and to improve the diagnostic capacity of the test, multiplex PCR, a variant of the test in which more than one target sequence is amplified using more than one pair of primers, has been developed. Multiplex PCRs to detect viral, bacterial, and/or other infectious agents in one reaction tube have been described. Early studies highlighted the obstacles that can jeopardize the production of sensitive and specific multiplex assays, but more recent studies have provided systematic protocols and technical improvements for simple test design. The most useful of these are the empirical choice of oligonucleotide primers and the use of hot start-based PCR methodology. These advances along with others to enhance sensitivity and specificity and to facilitate automation have resulted in the appearance of numerous publications regarding the application of multiplex PCR in the diagnosis of infectious agents, especially those which target viral nucleic acids. This article reviews the principles, optimization, and application of multiplex PCR for the detection of viruses of clinical and epidemiological importance.

Multiplex PCR: optimization and application in diagnostic virology

PCR has revolutionized the field of infectious disease diagnosis. To overcome the inherent disadvantage of cost and to improve the diagnostic capacity of the test, multiplex PCR, a variant of the test in which more than one target sequence is amplified using more than one pair of primers, has been developed. Multiplex PCRs to detect viral, bacterial, and/or other infectious agents in one reaction tube have been described. Early studies highlighted the obstacles that can jeopardize the production of sensitive and specific multiplex assays, but more recent studies have provided systematic protocols and technical improvements for simple test design. The most useful of these are the empirical choice of oligonucleotide primers and the use of hot start-based PCR methodology. These advances along with others to enhance sensitivity and specificity and to facilitate automation have resulted in the appearance of numerous publications regarding the application of multiplex PCR in the diagnosis of infectious agents, especially those which target viral nucleic acids. This article reviews the principles, optimization, and application of multiplex PCR for the detection of viruses of clinical and epidemiological importance.

PCR and restriction endonuclease analysis for rapid identification of human adenovirus subgenera

Subgenus identification of adenoviruses is of clinical importance and is as informative as identification by serotype in most clinical situations. A PCR-based identification of adenovirus subgenera A, B, C, D, E, and F and sometimes serotypes is described. The PCR uses nonnested primer pair ADRJC1-ADRJC2, which targets a highly conserved region of the adenovirus hexon gene, has a sensitivity of 10 to 40 copies of adenovirus type 2 (Ad2) DNA, and generates 140-bp PCR products from adenovirus serotypes representative of all the subgroups. The PCR products of all subgroups can be differentiated on the basis of the restriction fragment patterns produced by a total of five restriction endonucleases. In addition, serotypes Ad40 and Ad41 (subgroup F) and important serotypes of subgroup D (Ad8, Ad10, Ad19, and Ad37) can easily be differentiated, but serotypes within subgroups B and C cannot. The method was assessed by blind subgenus identification of 56 miscellaneous clinical isolates of adenoviruses. The identities of these isolates at the subgenus level by the PCR correlated 91% (51 of 56) with the results of serotyping by the neutralization test, and 9% (5 of 56) of clinical isolates produced discordant results.