Microbiology Case Study: A 28 Year Old Female with Perirectal Abscess

Case History

A 28 year old female with a history of Ulcerative Colitis on humira and azathioprine presented with proctitis and a recent perirectal abscess. The patient reported a two week history of progressively worsening pain and swelling in the perianal region. In addition, she reported recent purulence excreted with bowel movements.  On physical exam, the patient was afebrile and negative for rash, oral lesions, joint pain, or abdominal pain. A perirectal abscess was identified and drained. Abscess culture was positive. Patient reported recently engaging in high-risk sexual behavior with multiple male sexual partners often without protection.

Lab Identification

Image 1. Kidney-bean shaped gram negative cocci identified on Gram staining of perirectal abscess culture (100x oil immersion).  
Image 2. Aerobic growth of flat, gray-white, and moist colonies from perirectal abscess on chocolate agar plate.  

Abscess culture grew kidney-bean shaped gram negative diplococci. Colonies on chocolate agar plate appeared medium sized, flat, gray-brown, and moist. The organism was oxidase positive and identified by MALDI to be Neisseria gonorrhoeae.


Neisseria gonorrhoeae is a kidney-bean shaped gram negative diplococci for which humans are the only host. The organism causes gonorrhea, a common sexually transmitted disease, among young people between the ages of 15-24 years. Gonorrhea is spread by sexual contact or through the birth canal. The most common site of infection is the urogenital tract.2 Males commonly present with dysuria with penile discharge.2 Females commonly present asymptomatically or with symptoms such as mild vaginal mucopurulent discharge and severe pelvic pain2. In addition, gonorrhea can cause infections of the anus, conjunctiva, pharynx, ovary and uterus.2 In the neonate, the culprit organism can lead to ophthalmia neonatorum.2 Lastly, gonorrhea causes disseminated disease such as arthritis, endocarditis, meningitis, and skin lesions on extremities.2 CDC currently recommends treating gonorrhea with dual therapy, a single dose of 250 mg intramuscular ceftriaxone and 1g of oral azithromycin.1

Antibiotic resistance in gonorrhea is an increasing public health concern. The World Health Organization has a program that monitors the global antimicrobial resistance of gonorrhea.3 The data from 77 countries between 2009 and 2014 showed that 66% of reporting countries had encountered gonorrhea strains with either resistance or reduced susceptibility to ceftriaxone.3 81% of reporting countries had encountered gonorrhea strains resistant to azithromycin.3 Given these data, it is important to improve gonorrhea prevention and continue to monitor gonorrhea antibiotic resistance at both the national and global levels.


  1. Gonorrhea treatment and care. (2017, Oct 31st). Retrieved on March 1st, 2018 from https://www.cdc.gov/std/gonorrhea/treatment.htm
  2. Miller KE. Diagnosis and Treatment of Neisseria gonorrhoeae Am Fam Physician. 2006 May 15:73 (10): 1779-1784.
  3. Wi T, et al. Antimicrobial resistance in Neisseria gonororheae: Global surveillance and a call for international collaborative action. PLoS Med 14(7): e1002344.https://doi.org/10.1371/journal.pmed.1002344


-Ting Chen, MD is a 1st year anatomic and clinical pathology resident at the University of Vermont Medical Center.


-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

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