Gonorrhea laboratory tests
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]
Overview
Empiric treatment for gonorrhea is usually initiated prior to the receipt of laboratory results. A microbiologic diagnosis is important for further management in order to determine the need for test of cure, partner management, and for public health reasons. Any sexually active man or women presenting with signs and symptoms of urethritis, cervicitis, pelvic inflammatory disease, or epididymitis should undergo diagnostic testing for Neisseria gonorrhea. Additionally, disseminated gonococcal infection (DGI) should be considered in all young, sexually active individuals who present with arthralgias or suspected septic arthritis. Common laboratory tests for gonococcal infection may include Gram stain, culture, nucleic acid amplification tests (NAAT), and non-amplified tests. Nucleic acid amplification tests (NAATs) are the test of choice in all individuals who present with urogenital symptoms.[1][2] Additionally, synovial fluid analysis is usually sent for cell count, differential, Gram stain, bacterial culture, and NAAT in patients with suspected DGI.[3]
Laboratory tests
Several laboratory tests are available to diagnose gonorrhea. A clinician can obtain a sample for testing from the parts of the body most likely to be infected (e.g., cervix, urethra, rectum, or throat) and send the sample to a laboratory for analysis. Gonorrhea that is present in the cervix or urethra can be diagnosed in a laboratory by testing a urine sample.[1][4]
Diagnostic Techniques
Gram stain
- Gram stain of urethral discharge is highly sensitive and specific in men with symptomatic urethritis
- Gram stain of endocervical, pharyngeal, and rectal specimens is insufficient and is not recommended
- In symptomatic men, polymorphonuclear leukocytes (PMNs) with intracellular gram-negative diplococci can be considered diagnostic for infection with Neisseria gonorrhea.
- Common anatomic sites for taking samples include:[1][4][5]
- Urethral discharge in men
- Synovial fluid
- Cervix in women
-
![Neisseria gonorrhoeae in cervical smear using the Gram-stain - Source: https://www.cdc.gov/[6]](/images/0/0c/Gonorrhea14.jpeg)
Neisseria gonorrhoeae in cervical smear using the Gram-stain - Source: https://www.cdc.gov/[6]
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![Urethral discharge for Neisseria gonorrhea revealed Gram-negative intracellular rods - Source: https://www.cdc.gov/[6]](/images/a/a2/Gonorrhea13.jpeg)
Urethral discharge for Neisseria gonorrhea revealed Gram-negative intracellular rods - Source: https://www.cdc.gov/[6]
-
![Intracellular Gram-negative diplococcal - Source: https://www.cdc.gov/ [6]](/images/a/aa/Gonorrhea05.jpeg)
Intracellular Gram-negative diplococcal - Source: https://www.cdc.gov/ [6]
![Neisseria gonorrhoeae in cervical smear using the Gram-stain - Source: https://www.cdc.gov/[6]](/index.php/File:Gonorrhea14.jpeg)
![Urethral discharge for Neisseria gonorrhea revealed Gram-negative intracellular rods - Source: https://www.cdc.gov/[6]](/index.php/File:Gonorrhea13.jpeg)
![Intracellular Gram-negative diplococcal - Source: https://www.cdc.gov/ [6]](/index.php/File:Gonorrhea05.jpeg)
Cultures
Culture (Thayer-Martin medium) is the historical standard for detection of Neisseria gonorrhea.
- Advantages of culture over non-culture tests include:[1][7]
- Low cost
- Suitable for a variety of specimen sites
- Antimicrobial susceptibility testing can be performed
- Common anatomic sites for taking samples include:
- Vaginal and cervical
- Urethral discharge in men
- Pharyngeal
- Rectal
- Synovial fluid
- Blood cultures
Nucleic Acid Amplification Tests (NAATs)
NAATs are the gold standard for diagnosing gonococcal infections.
Amplified tests include:[1][8][9]
- Polymerase chain reaction (PCR)
- Transcription-mediated amplification (TMA)
- Strand displacement amplification (SDA)
NAAT is FDA-cleared for:
- Endocervical swabs from women
- Urethral swabs from men
- Urine specimens from both males and females
- Vaginal swabs
NAAT is not FDA-cleared for detection of rectal, oropharyngeal, or conjunctival gonococcal infection.
- There is a concern about cross-reactivity with other Neisseria species when used at the oropharyngeal site.[7]
- Some laboratories have met CLIA regulatory requirements and established performance specifications for using NAAT with rectal and oropharyngeal swab specimens that can inform clinical management.
- Antimicrobial susceptibility cannot be determined with these tests. However, the same specimen can be evaluated for Chlamydia trachomatis.
Non-amplified tests
Non-amplified tests used for Neisseria gonorrhea include:
- DNA probe (e.g., Gen-Probe PACE 2 and Digene Hybrid Capture II)
Antimicrobial susceptibility cannot be determined with these tests. However, the same specimen can be evaluated for Chlamydia trachomatis.
Non-disseminated gonococcal infection
Empiric treatment for gonorrhea is usually initiated prior to receipt of laboratory results. However, a microbiologic diagnosis is important for further management in order to determine the need for test of cure, partner management, and for public health reasons. Any sexually active man or women presenting with signs and symptoms of urethritis, cervicitis, pelvic inflammatory disease, or epididymitis should undergo diagnostic testing for Neisseria gonorrhea.
Men with urogenital presentation
- Urethral swabs or first-catch urine (20 to 30 mL of the initial urinary stream) specimens for NAAT are tests of choice
- Positive Gram stain of urethral swab is also sufficient, in which case NAAT is not necessary
- Urethral swab specimens for Gram stain, culture, antigen detection, and genetic probe methods are also acceptable (if NAAT is unavailable)
Women with urogenital presentation
- Vaginal swab or endocervical swab specimens for NAAT are tests of choice
- Urine and liquid Pap smear specimens for NAAT are also acceptable
- Endocervical swabs specimens for Gram stain, culture, antigen detection, and genetic probe method are also acceptable (if NAAT are unavailable)
Men and women with extragenital presentation
- Rectal and pharyngeal swabs for NAAT are the preferred diagnostic tests for these sites
- Rectal and pharyngeal swabs for culture can also be used
Disseminated gonococcal infection
In general, disseminated gonococcal infection (DGI) should be considered in all young, sexually active individuals (young women and all men who have sex with men) who present with arthralgias, joint pain, or suspected septic arthritis.
- Gonococcal arthritis and DGI are associated with mild leukocytosis and elevated ESR in about 50% of patient.[10]
Common laboratory findings of disseminated gonococcal infection (DGI) may include the following:[2]
Blood Culture
- Blood cultures are diagnostic and more likely to be positive in patients with arthritis-dermatitis syndrome (less than 30% of patients)
- Blood cultures are helpful in differentiating DGI from other conditions such as septic arthritis due to Neisseria meningitidis or Staphylococcus aureus
Synovial fluid
- Synovial fluid analysis is usually sent for cell count, differential, Gram stain, bacterial culture and NAAT in patients with suspected DGI[3]
- Synovial fluid cultures are positive for Neisseria gonorrhoeae in approximately 50% patients with purulant gonococcal arthritis
- Synovial fluid cultures are less likely to be positive in patients with arthritis-dermatitis syndrome (usually contains fewer than 20,000 leukocytes/mm3 or is sterile)[11]
- Synovial fluid leukocyte count in gonococcal septic arthritis ranges from approximately 10,000 cells/mm3 to 50,000 cells/mm3[12]
- Synovial fluid glucose, lactate dehydrogenase, or protein in gonococcal arthritis have only limited value
Mucosal sites specimens
- Urogenital, rectal, and pharyngeal specimens should be sent for culture and NAAT in all patients with suspected DGI.
- Positive urogenital, rectal, or pharyngeal infection are generally seen in patients with DGI. However, most patients with DGI are asymptomatic at these sites.
Skin lesion specimens
- In the pustular skin lesions, the specimens can be sent for Gram stain, culture, and NAAT
- NAAT and cultures are not routinely done in patients with suspected DGI[13]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 "Sexually transmitted diseases treatment guidelines (2015)." Reproductive Endocrinology 24 (2015): 51-56.http://www.cdc.gov/std/tg2015/gonorrhea.htm Accessed on September 2015
- ↑ 2.0 2.1 Rice PA (2005). "Gonococcal arthritis (disseminated gonococcal infection)". Infect Dis Clin North Am. 19 (4): 853–61. doi:10.1016/j.idc.2005.07.003. PMID 16297736.
- ↑ 3.0 3.1 Muralidhar B, Rumore PM, Steinman CR (1994). "Use of the polymerase chain reaction to study arthritis due to Neisseria gonorrhoeae". Arthritis Rheum. 37 (5): 710–7. PMID 8185698.
- ↑ 4.0 4.1 Unemo M, Ison C. 2013. Gonorrhoea, p 21–54 In Laboratory diagnosis of sexually transmitted infections, including human immunodeficiency virus. World Health Organization (WHO), Geneva, Switzerland
- ↑ Centers for Disease Control and Prevention (2014) Recommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae--2014. MMWR Recomm Rep 63 (RR-02):1-19. PMID: 24622331
- ↑ 6.0 6.1 6.2 Centers for Disease Control and Prevention. Public Health Image Library (PHIL) https://phil.cdc.gov/phil/quicksearch.asp Accessed on September 22, 2016
- ↑ 7.0 7.1 Papp, John R., et al. "Recommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae—2014." MMWR. Recommendations and reports: Morbidity and mortality weekly report. Recommendations and reports/Centers for Disease Control 63 (2014): 1.http://www.cdc.gov/mmwr/preview/mmwrhtml/rr6302a1.htm
- ↑ Schachter J, Moncada J, Liska S, et al. Nucleic acid amplification tests in the diagnosis of chlamydial and gonococcal infections of the oropharynx and rectum in men who have sex with men. Sex Transm Dis 2008;35:637–42.
- ↑ Bachmann LH, Johnson RE, Cheng H, et al. Nucleic acid amplification tests for diagnosis of Neisseria gonorrhoeae oropharyngeal infections. J Clin Microbiol 2009;47:902–7.
- ↑ García-De La Torre, Ignacio, and Arnulfo Nava-Zavala. "Gonococcal and nongonococcal arthritis." Rheumatic Disease Clinics of North America 35.1 (2009): 63-73.
- ↑ Liebling MR, Arkfeld DG, Michelini GA, Nishio MJ, Eng BJ, Jin T; et al. (1994). "Identification of Neisseria gonorrhoeae in synovial fluid using the polymerase chain reaction". Arthritis Rheum. 37 (5): 702–9. PMID 8185697.
- ↑ Goldenberg, D. L. "Gonococcal arthritis and other Neisserial infections." Arthritis and allied conditions, 12th ed. Philadelphia: Lea and Febiger (1993): 2025-33.
- ↑ Read P, Abbott R, Pantelidis P, Peters BS, White JA (2008). "Disseminated gonococcal infection in a homosexual man diagnosed by nucleic acid amplification testing from a skin lesion swab". Sex Transm Infect. 84 (5): 348–9. doi:10.1136/sti.2008.030817. PMID 18809698.