Microbiology Case Study: Pain and Discharge from the Eye of a 27 Year Old Female

Case presentation

A 27 year old female with a history of substance abuse, presented to the ED with a swollen left eye, resulting from a fall in the shower that hit her eye on the tub. She denies losing consciousness or neck pain. Her eye has swollen since then and she noticed yellow drainage from her eye. Her past medical history was unremarkable although she was diagnosed as having sexually transmitted infections (STI) with Neisseria gonorrhoeae and Chlamydia trachomatis 3 months prior to the current event. Her HIV and syphilis screening were negative. 

The drainage from her eye was collected for culture and Gram stain and sent to the Microbiology laboratory. The initial Gram stain showed moderate neutrophils and very few gram negative diplococci (GNDC). The culture grew pure growth of the same organism on Chocolate agar during overnight incubation. It was identified as Neisseria gonorrhoeae by MALDI-ToF. The patient was reached out by the emergency nurses for the Ceftriaxone injection. 

Discussion

Neisseria gonorrhoeae belong to the Neisseriaceae family, including Kingella, Eikenella, and many other genera. Neisseria gonorrhoeae is gram negative cocci in pairs and have a distinct kidney bean shape. They thrive in the mucous membranes of the respiratory and urogenital tracts.¹ While the pathogenicity tends to vary among Neisseria spp; N. gonorrhea is a primary pathogen that does not belong in the usual flora of humans in any amount, unlike other Neisseria that are opportunistic and can be part of usual flora.¹ N. gonorrhoeae only has been reported in human cases. N. gonorrhoeae and N. meningitidis are considered fastidious organisms that require CO2 and iron. These organisms are aerobic bacteria that only grow on chocolate media that has RBC hemolyzed. When N. gonorrhoeae infects humans; it has a surface receptor that binds transferrin directly competing with the human host for iron supplies.¹ Transferrin is a glycoprotein that delivers iron throughout the body.²

N. gonorrhoeae is typically acquired through unprotected sexual activity. Once transmitted, it can be found in vaginal, oral and anal secretions.³ The recorded cases of N. gonorrhoeae in 2018-2019 have gone up 5.9%; since 2009 there has been a 92.0% increase in cases, with a lot more young men contracting the disease since 2009.³ Improvement in screening and tracking techniques can also be a reason for the drastic increase in U.S cases.³ While most of the time N. gonorrhoeae stays in the mucosal membranes, it can also thrive in other parts of the body.¹ The most common genital infection causes painful urination, a pus-like substance that discharges from the penis, and pain and tenderness in the testicular region.⁴ For women, it can cause increased discharge, pelvic pain, and bleeding between periods.⁴ Untreated genital N. gonorrhoeae can cause pelvic inflammatory disease (PID) which can lead to abortion and sterility in both men and women.¹ N. gonorrhoeae also has the potential to affect but is not limited to the rectum, eyes, throat, and joints where it can cause pain, swelling, and rashes.⁴ Pregnant women that have an N. gonorrhoeae infection can pass it onto their offspring through vaginal delivery, and it is very important to screen for N. gonorrhoeae during pregnancy.⁴ In the US providers must put antimicrobial (erythromycin) eye drops in the babies born regardless of the STD status of the mother.¹ A neonate exposed to N. gonorrhoeae can develop blindness and rashes.¹ Untreated N. gonorrhoeaecan commonly causes recurrent rectal infection in women. While ocular gonococcal eye infection can be encountered more frequently in neonates born to infected mothers through vaginal delivery, ocular gonococcal infections in adults are extremely rare and can potentially be caused by incidental inoculation of infected genital secretions of their own (auto-infection).¹ 

In most cases, N. gonorrheae can be cultured from a swab of the male urethral or female endocervix, or vaginal samples. Non-genital samples, such as rectal and oral sources can also be used to diagnose extra-genital gonococcal infections. Nucleic acid amplification tests (NAAT) are commonly used for rapid diagnosis of gonococcal infection from genital, anal, or oral sources. For samples collected from other sources, culture is the primary method of the diagnostic approach. N. gonorrhoeae grows well on chocolate agar. MTM (modified Thayer martin) agar supports the growth of N. gonorrhoeae as it is a selective media for N. gonorrhoeae, containing nystatin, colistin, and vancomycin to suppress the growth of other bacteria.⁵ N. gonorrhoeae was susceptible to penicillin in 1976, and, by 1980, penicillinase-producing N. gonorrhoeae was discovered in Southwest Asia.¹ The most common treatment is ceftriaxone intramuscularly with oral azithromycin for those who are allergic to cephalosporins like ceftriaxone gemifloxacin or injectable gentamicin.⁴

References

1. Mahon, C. R., & Lehman, D. C. (2019). Textbook of diagnostic microbiology. Elsevier Saunders.
2. Ogun, A. S. (2021, July 31). Biochemistry, transferrin. StatPearls [Internet].
3. Centers for Disease Control and Prevention. (2014, January 29). Std facts – gonorrhea.
4. Mayo Foundation for Medical Education and Research. (2021, October 5). Gonorrhea.
5. Cheng, A., & Kirby , J. (2014, March). Evaluation of the hologic gen-probe panther, APTIMA Combo 2 assay in a tertiary care teaching hospital. American journal of clinical pathology. 

-Alejandro Soto, MLS(ASCP)^CM

-Phyu M. Thwe, Ph.D., D(ABMM), MLS(ASCP)^CM is Microbiology Technical Director at Allina Health Laboratory in Minneapolis, MN. She completed her CPEP microbiology fellowship at the University of Texas Medical Branch in Galveston, TX. Her interest includes appropriate test utilization and extra-pulmonary tuberculosis.