Chlamydia trachomatis Antigen Positivity in Patients with Different Ocular Manifestations over 8 Years.

Laboratory confirmation of chlamydial antigen in clinically suspected cases of chlamydial eye infections is important, as similar clinical picture can be presented by different infective or noninfective causes. We retrospectively analyzed the presence of Chlamydia trachomatis antigen in 690 clinically suspected patients over the last 8 years (2009-2016). The chlamydial antigen was detected using direct immunofluorescence assay. Overall, Chlamydia-specific antigen positivity was 45.5%. The highest positivity was seen in 2014 (68.6%) and the least in 2016 (9.4%). The antigen positivity in years 2015 (13.4%) and 2016 (9.4%) was significantly less than in all the previous study years (P < 0.0001). Antigen positivity in patients having clinical diagnosis of trachoma was significantly higher than those having other eye manifestations suggestive of chlamydial infections (P = 0.0274). Stringent surveillance both at community level and in hospital attendees is required to know the actual load of this pathogen.

INTRODUCTION

Ocular infections with Chlamydia trachomatis have been a huge challenge for ophthalmologists, microbiologists, and community health-care workers alike. Trachoma is caused by the ocular serotypes (A, B, Ba, and C) of the bacterium, whereas the other serotypes (D, E, F, G, H, I, J, and K) are associated with inclusion conjunctivitis.[1] Severe inclusion conjunctivitis, especially in neonates, has high incidence of outcomes generally seen in trachoma.[23]

The study was undertaken to analyze the presence of C. trachomatis antigen in patients with different ocular manifestations over the last 8 years (2009–2016).

MICROBIOLOGY REPORT

Conjunctival swabs from 690 patients referred for detection of chlamydial antigen from 2009 to 2016 were subjected to direct immunofluorescence assay, which is the Centers for Disease Control and Prevention-recommended method for diagnosing C. trachomatis infection in ocular specimens.[4] Chlamydial elementary bodies appeared as round, bright, apple green, fluorescent particles, regular in outline, and 10 or more elementary bodies in a pair of eyes were interpreted as positive.[5]

Of the 690 patients, 380 were males and 310 were females, ranging in age from 1 year to 80 years. Maximum number of patients was from age group 21 to 30 years and maximum Chlamydia-specific antigen positivity was seen in age group 0 to 10 years [Table 1]. The overall antigen positivity was 45.5% (314 out of 690 patients). From 2009 to 2016, the percentage positivity for Chlamydia-specific antigen was 39.4%, 62.2%, 51.8%, 59.0%, 61.8%, 68.6%, 13.4%, and 9.4%, respectively. The highest antigen positivity was seen in 2014 (68.6%) and the least in 2016 (9.4%). The Chlamydia-specific antigen positivity in the years 2015 (13.4%) and 2016 (9.4%) was significantly less than in all the previous study years (P < 0.0001); however, there was no significant difference between the antigen positivity of years 2015 and 2016 (P = 0.4715) [Table 2 and Figure 1].

Table 1

Demographic distribution of specimens tested and Chlamydia trachomatis antigen positivity in the study

Table 2

Chlamydia trachomatis antigen positivity in patients of different age groups from the years 2009 to 2016

Figure 1

Graph showing C. trachomatis antigen positivity in patients of different age groups from the year 2009 to 2016

Based on the clinical diagnosis, patients were divided into four groups – trachoma group; follicular, acute, or chronic conjunctivitis group; keratoconjunctivitis group; and a group of other eye manifestationssuggestive of chlamydial infections. The difference between antigen positivity in patients having “trachoma” and those having “other eye manifestations” was statistically significant (P = 0.0274) [Table 3 and Figure 2].

Table 3

Chlamydia trachomatis antigen positivity in patients with different clinical diagnosis from the years 2009 to 2016

Figure 2

Graph showing C. trachomatis antigen positivity in patients with different clinical diagnosis from the year 2009 to 2016

CONCLUSION

Undiagnosed and hence improperly managed chronic ocular chlamydial infections continue to be a burden in terms of ocular morbidity and vision loss. Stringent surveillance in the coming years is needed to know its burden both in community and in the referral centers with varied ocular manifestations.

Financial support and sponsorship

This study was done from internal funding by Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.

Conflicts of interest

There are no conflicts of interest.