LETTER TO EDITOR
|Year : 2022 | Volume
| Issue : 2 | Page : 238-240
Accuracy of Gram-stained smears as screening tests for Neisseria gonorrhoeae: Brief communication
Mohamed Abdalla Khalid
Department of Laboratory, Kamal Medical Polyclinics, Riyadh, Saudi Arabia
|Date of Submission||06-Dec-2020|
|Date of Decision||28-Feb-2022|
|Date of Acceptance||02-Mar-2022|
|Date of Web Publication||17-Nov-2022|
Dr. Mohamed Abdalla Khalid
Department of Laboratory, Kamal Medical Polyclinics, Riyadh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Khalid MA. Accuracy of Gram-stained smears as screening tests for Neisseria gonorrhoeae: Brief communication. Indian J Sex Transm Dis 2022;43:238-40
|How to cite this URL:|
Khalid MA. Accuracy of Gram-stained smears as screening tests for Neisseria gonorrhoeae: Brief communication. Indian J Sex Transm Dis [serial online] 2022 [cited 2023 Nov 30];43:238-40. Available from: https://ijstd.org/text.asp?2022/43/2/238/361309
Neisseria gonorrhoeae (Ng) is an etiologic agent of gonorrhea, one of the most common sexually transmitted diseases caused by bacteria. Which has an estimated global annual incidence of 86.9 million adults. A presumptive gonorrhea diagnosis can be made based on light microscopic detection of the bacterium in Gram-stained smears (GSS). This enables immediate treatment, thus preventing ongoing transmission and/or loss to follow-up.
The present study reviewed the diagnostic accuracy variables (sensitivity, specificity, likelihood ratios [LRs], and diagnostic odds ratios [DORs]) of gram GSS that screen for Ng in urethral swabs and endocervical swabs specimens. Author evaluated studies conducted worldwide in adults by searching MEDLINE (through PubMed) from 1980 to 2020. This study included studies conducted in adult humans if they provided enough raw data to recreate the 2 × 2 diagnostic tables. The author did not exclude articles on the basis of study location or study design. [Figure 1] shows a flowchart of the search. The author conducted the searches and screened articles for eligibility. After initial identification of all studies and deletion of duplicates, the author did a preliminary screening of 937 articles based on title and abstract. Of which, 26 were considered for full-text review. Eleven articles were retrieved and included in the study.
The present study assessed the methodological and reporting quality of studies using the (Quality Assessment of Diagnostic Accuracy Studies 2) tool [Figure 2]. All statistical analyses were carried out in Intercooled Stata, version 15 (StataCorp, College Station, Texas, USA). The sensitivity, specificity, positive LR, negative LR, and DOR were calculated [Table 1] and [Table 2]. LRs of a test inform the pretest probability of disease and provide a posttest probability. A positive LR higher than 5 and a negative LR <0.2 provide strong diagnostic evidence.
|Table 2: Results of meta-analysis, by specimen and reference standard subgroup|
Click here to view
Of the 11 total studies, 3 (27%) were conducted in developing settings,, and 8 (73%) were conducted in developed settings.,,,,,,, Sample sizes ranged from 95 to 27,600 persons.
To interpret study results, first, reference standards were found to influence the accuracy of GSS. Second, the effect of antimicrobial susceptibility testing on diagnostic accuracy is worth further consideration. Third, the index tests included in this study detected intercellular diplococcus Ng and therefore could not detect infection within about 2–10 days. Finally, evidence on GSS will be of greater use to policymakers and guideline developers if outcomes beyond accuracy are documented.
In conclusion, GSS offers many advantages: A fast turnaround time, declaration of results at the point of care with the potential for affecting clinical management, and early detection of undiagnosed cases of gonorrhea. This study found GSS to be accurate and suitable for screening initiatives.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Rubin DH, Ross JD, Grad YH. The frontiers of addressing antibiotic resistance in Neisseria gonorrhoeae
. Transl Res 2020;220:122-37.
Thairu Y, Nasir I, Usman Y. Laboratory perspective of gram staining and its significance in investigations of infectious diseases. Sub Saharan Afr J Med 2014;1:168-74.
Bhargava A, Bala M, Singh V, Joshi NC, Kakran M, Puri P, et al.
How reliable is microscopy and culture for the diagnosis of gonorrhea? An 11-year experience from India. Sex Transm Dis 2017;44:111-3.
Goodhart ME, Ogden J, Zaidi AA, Kraus SJ. Factors affecting the performance of smear and culture tests for the detection of Neisseria gonorrhoeae
. Sex Transm Dis 1982;9:63-9.
Taylor SN, DiCarlo RP, Martin DH. Comparison of methylene blue/gentian violet stain to gram's stain for the rapid diagnosis of gonococcal urethritis in men. Sex Transm Dis 2011;38:995-6.
Goh BT, Varia KB, Ayliffe PF, Lim FK. Diagnosis of gonorrhea by gram-stained smears and cultures in men and women: Role of the urethral smear. Sex Transm Dis 1985;12:135-9.
D'Angelo LJ, Mohla C, Sneed J, Woodward K. Diagnosing gonorrhea. A comparison of standard and rapid techniques. J Adolesc Health Care 1987;8:344-8.
Orellana MA, Gómez-Lus ML, Lora D. Sensitivity of gram stain in the diagnosis of urethritis in men. Sex Transm Infect 2012;88:284-7.
Bartelsman M, Straetemans M, Vaughan K, Alba S, van Rooijen MS, Faber WR, et al.
Comparison of two gram stain point-of-care systems for urogenital gonorrhoea among high-risk patients: Diagnostic accuracy and cost-effectiveness before and after changing the screening algorithm at an STI clinic in Amsterdam. Sex Transm Infect 2014;90:358-62.
Borg S, Daniel J, Forsyth S. Is urethral microscopy useful in symptomatic male patients without urethral discharge? Int J STD AIDS 2019;30:79-81.
Juchau SV, Nackman R, Ruppart D. Comparison of gram stain with DNA probe for detection of Neisseria gonorrhoeae
in urethras of symptomatic males. J Clin Microbiol 1995;33:3068-9.
Situ SF, Ding CH, Nawi S, Johar A, Ramli R. Conventional versus molecular detection of Chlamydia trachomatis
and Neisseria gonorrhoeae
among males in a sexually transmitted infections clinic. Malays J Pathol 2017;39:25-31.
Hananta IP, van Dam AP, Bruisten SM, van der Loeff MF, Soebono H, Christiaan de Vries HJ. Value of light microscopy to diagnose urogenital gonorrhoea: A diagnostic test study in Indonesian clinic-based and outreach sexually transmitted infections services. BMJ Open 2017;7:e016202.
Jaeschke R, Guyatt GH, Sackett DL. Users' guides to the medical literature. III. How to use an article about a diagnostic test. B. What are the results and will they help me in caring for my patients? The evidence-based medicine working group. JAMA 1994;271:703-7.
Verma R, Sood S. Gonorrhoea diagnostics: An update. Indian J Med Microbiol 2016;34:139-45.
] [Full text]
Unemo M, Seifert HS, Hook EW, Hawkes S, Ndowa F, Dillon JA. Gonorrhoea. Nat Rev Dis Primers 2019;5:79.
17Whittles LK, White PJ, Didelot X. A dynamic power-law sexual network model of gonorrhoea outbreaks. PLoS Comput Biol 2019;15:e1006748.
Raffe S, Soni S. Diagnostic tests for sexually transmitted infections. Medicine (Baltimore) 2018;46:277-82.
[Figure 1], [Figure 2]
[Table 1], [Table 2]