A misleading urethral smear with polymorphonuclear leucocytes and intracellular diplococci; case report of urethritis caused by Neisseria meningitidis

[Neisseria meningitidis and the increase of oral sex. A case report]

Urethritis is an entity characterized by dysuria and purulent urethral discharge, generally acquired sexually. Neisseria gonorrhoeae is one of the most frequently responsible microorganisms. Neisseria meningitidis is a gram-negative diplococcus usually isolated in the pharynx, that occasionally causes meningococcal meningitis, being unusual it's isolation in the anogenital area where it could be a genitourinary pathogen. We present the case of a 25-years-old heterosexual male who, after a heterosexual intercourse with an occasional non-professional partner, including oral and vaginal sex, presented with symptoms of urethritis, orienting to a sexually transmitted infection. The bacteriological culture for N. gonorrhoeae was negative and the PCR for Chlamydia trachomatis was positive. Subsequently, the lab reported a positive bacteriological culture for sero-group C N. meningitidis, sensitive to ceftriaxone and a negative PCR for N. gonorrhoeae. N. meningitidis is the main cause of bacterial meningitis, but genomic studies have suggested that alleles of nitrate reductase, factor-H biding protein and capsule are associated with N. meningitidis isolation in genitourinary infections. Transmission from the oropharynx to the urethra through orogenital contact in unprotected oral sex has been widely proven. N. meningitidis prevalence as the cause of the urethritis is low, and the asymptomatic carriers in the urethra are extremely rare. PCR is a method for the N. gonorrhoeae and C.trachomatis diagnoses, but it does not detect N. meningitidis. The gonorrhoea diagnosis is based on an increased number of polymorphonuclear cells, with intracellular gram-negative diplococci in Gram' stain of urethral discharge. In our case, the gram-negative diplococcus seen in the stain was a meningococcus. Urethritis due to N. meningitidis is indistinguishable from the secondary to N. gonorrhoeae, mimicking it even microscopically, only the epidemiology varies. The conventional bacteriological culture continues to be essential for a correct diagnosis.

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

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.

Neisseria Meningitidis Urethritis in a Thai Male

Although Neisseria meningitidis (N. meningitidis) urogenital infections have been reported widely, meningococcal urethritis has not been reported previously in Thailand. A 42-year-old Thai male presented at a sexual health clinic with dysuria and urethral discharge following oral and insertive anal intercourse. N. meningitidis, serogroup C was cultured from a urethral discharge specimen and the patient was treated successfully with standard treatment for gonococcal urethritis. This case reflects a growing trend of reports describing meningococcal urethritis, likely resulting from sexual contact.

Meningococcal disease and sexual transmission: urogenital and anorectal infections and invasive disease due to Neisseria meningitidis

Neisseria meningitidis is an obligate human commensal bacterium that frequently colonises the upper respiratory tract. Person-to-person transmission occurs via direct contact or through dispersion of respiratory droplets from a carrier of the bacteria, and can lead to invasive meningococcal disease. Rare sporadic cases of meningococcal urogenital and anorectal infections, including urethritis, proctitis, and cervicitis, have been reported, typically following orogenital contact with an oropharyngeal meningococcal carrier. The resulting infections were clinically indistinguishable from infections caused by Neisseria gonorrhoeae. Over the past two decades, there have also been multiple outbreaks across North America and Europe of invasive meningococcal disease among men who have sex with men (MSM). The responsible meningococci belong to a highly virulent and predominantly serogroup C lineage, including strains that are able to express nitrite reductase and grow in anaerobic environments, such as the urogenital and anorectal tracts. More recently, a distinct clade within this lineage has expanded to cause urethritis predominantly among men who have sex with women. Evolutionary events giving rise to this clade included the loss of the ability to express a capsule, and acquisition of several gonococcal alleles, including one allele encoding a highly efficient gonococcal nitrite reductase. Members of the clade continue to acquire gonococcal alleles, including one allele associated with decreased antibiotic susceptibility. This evolution has implications for the clinical and public health management of those who are infected and their close contacts, in terms of both antibiotic treatment, and prevention through vaccination.

Neisseria meningitidis: using genomics to understand diversity, evolution and pathogenesis

Meningococcal disease remains an important cause of morbidity and death worldwide despite the development and increasing implementation of effective vaccines. Elimination of the disease is hampered by the enormous diversity and antigenic variability of the causative agent, Neisseria meningitidis, one of the most variable bacteria in nature. These features are attained mainly through high rates of horizontal gene transfer and alteration of protein expression through phase variation. The recent availability of whole-genome sequencing (WGS) of large-scale collections of N. meningitidis isolates from various origins, databases to facilitate storage and sharing of WGS data and the concomitant development of effective bioinformatics tools have led to a much more thorough understanding of the diversity of the species, its evolution and population structure and how virulent traits may emerge. Implementation of WGS is already contributing to enhanced epidemiological surveillance and is essential to ascertain the impact of vaccination strategies. This Review summarizes the recent advances provided by WGS studies in our understanding of the biology of N. meningitidis and the epidemiology of meningococcal disease.