Development of flow cytometry based adherence assay for Neisseria gonorrhoeae using 5′-carboxyfluorosceinsuccidyl ester

ABSTRACT Infection of the mucosa by Neisseria gonorrhoeaeinvolves adherence to and invasion of epithelial cells. Little is known, however, about the expression by mucosal epithelial cells of molecules that mediate cellular interactions between epithelial cells and neutrophils at the site of gonococcal infection. The aim of this study was to determine the expression of intercellular adhesion molecule 1 (ICAM-1) by epithelial cells during the process of gonococcal invasion. The highly invasive strain FA1090 and the poorly invasive strain MS11 were incubated with human endometrial adenocarcinoma (HEC-1-B) or human cervical carcinoma (ME-180) epithelial cells, after which ICAM-1 expression was measured by flow cytometry. After 15 h of infection with FA1090, expression of ICAM-1 increased 4.7- and 2.1-fold for HEC-1-B and ME-180 cells, respectively, whereas 15 h of infection of HEC-1-B cells with MS11 increased ICAM-1 expression only 1.6-fold. ICAM-1 expression was restricted to the cell surface, since no soluble ICAM-1 was detected. The distribution of staining was heterogeneous and mimicked that seen after treatment of HEC-1-B cells with the ICAM-1 agonist tumor necrosis factor alpha (TNF-α) in the absence of bacteria. PCR and dot blot analyses of ICAM-1 mRNA showed no change in levels over time in response to infection. Although TNF-α was produced by HEC-1-B cells after infection, the extent of ICAM-1 upregulation was not affected by neutralizing anti-TNF-α antiserum. Dual-fluorescence flow cytometry showed that the cells with the highest levels of ICAM-1 expression were cells with associated gonococci. We conclude that epithelial cells upregulate the expression of ICAM-1 in response to infection with invasive gonococci. On the mucosa, upregulation of ICAM-1 by infected epithelial cells may function to maintain neutrophils at the site of infection, thereby reducing further invasion of the mucosa by gonococci.

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Profile of sexually transmitted infections causing urethritis and a related inflammatory reaction in urine among heterosexual males: A flow-cytometry study

PLoS ONE ◽

10.1371/journal.pone.0242227 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0242227

Author(s):

Stanislav Tjagur ◽

Reet Mändar ◽

Margus Punab

Keyword(s):

Flow Cytometry ◽

Chlamydia Trachomatis ◽

Neisseria Gonorrhoeae ◽

Trichomonas Vaginalis ◽

Screening Method ◽

Mycoplasma Genitalium ◽

University Hospital ◽

Control Group ◽

Sexually Transmitted ◽

Diagnostic Threshold

Background Information about the use of flow cytometry in the diagnosis of male urethritis is scarce. The current study aims to evaluate the performance of flow cytometry on first-voided urine in males with infectious urethritis (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis). Methods Male patients of the Andrology Centre (Tartu University Hospital, Estonia) were recruited during the period March 2015 –January 2018. Cases included 306 patients with infectious urethritis caused by Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and/or Trichomonas vaginalis. The control group consisted of 192 patients without uro-genital complaints, negative tests for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis from first-voided urine and no inflammation in first-voided urine, mid-stream urine and urine after prostate massage. C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis were detected from first-voided urine using polymerase chain reaction (PCR) method. First-voided urine was analysed using urine particle analyzer Sysmex UF-500i. Results The most prevalent infection was chlamydia (64.1%), followed by Mycoplasma genitalium (20.9%), gonorrhoea (7.8%) and trichomoniasis (1.6%). Gonorrhoea caused the highest flow-cytometric leucocyte/bacteria count, followed by chlamydia and Mycoplasma genitalium. Trichomonas vaginalis showed nearly absent inflammation in first-voided urine. Using an empiric flow-cytometry diagnostic threshold for urethritis in first-voided urine (leucocytes ≥ 15/μl and bacteria ≥ 20/μl) the total calculated sensitivity was over 90%. However, when applying such criteria for deciding whether to perform first-voided urine PCR for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis or not, we could miss 23 cases with infectious urethritis that makes up 7,5% of all proven cases. Conclusions Flow cytometry of first-voided urine can be considered as a rapid and objective screening method in case of suspected male infectious urethritis.

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