Vulvovaginitis due to Neisseria meningitidis in a 6-year-old girl

Neisseria meningitidis is a gram-negative diplococcus that can act as a commensal in mucosa of the upper respiratory and anogenital tracts, or produce disseminated meningococcal infection. Cases of urogenital and anogenital infection have also been reported. Here, we present a case.

A six-year-old female patient with a previous diagnosis of severe pulmonary stenosis treated with percutaneous pulmonary valvuloplasty attended the paediatric clinic due to dysuria and the appearance of greenish-yellow discharge without other notable alterations. Her physical examination was unremarkable and a test strip was negative. A vulvar swab was sent to our laboratory, from which a Gram stain was performed in which <5 PMNLs/1000 magnification field and intra/extracellular gram-negative diplococci were observed. After 24 h of incubation at 37 °C with an atmosphere of 5% CO₂, translucent, greyish convex colonies, oxidase positive, were isolated on chocolate and Thayer-Martin agar, identified as N. meningitidis by MALDI-TOF (LSV 2.57) and Filmarray® BCID Panel. The strain was classified by agglutination (Pastorex® Meningitis) as serogroup C. The strain showed sensitivity to ampicillin, cefotaxime, meropenem, tetracycline and ciprofloxacin. A culture of the pharyngeal sample was performed 48 h after the vaginal sample, which resulted negative for N. meningitidis. Treatment with amoxicillin/clavulanic acid was started and the case was reported to the Public Health Service due to possible legal implications. Throat and vulvar cultures were repeated one month later, both being negative for meningococcus.

Šikanić-Dugić et al. carried out a study in 115 girls with symptoms of vulvovaginitis aged between 2 and 8 years. In 33.04% of the patients, a bacterium was identified as the causal agent: S. pyogenes (n = 21; 55.3%), followed by H. influenzae (n = 5; 13.2%) and S. agalactiae (n = 4; 10.5%), among others. N. meningitidis was not detected in any of the cases¹. Isolation of N. meningitidis in genital samples is not uncommon², but it is an infrequent cause of vulvovaginitis in young girls³. There are case reports of meningococcal infection associated with sexual practices in both the heterosexual population and in men who have sex with men². Offman et al. reported a case of vulvovaginitis in an adult patient complicated by meningitis and septic shock, highlighting the need for rapid and correct identification of the aetiological agent⁴. Meanwhile, different outbreaks of disseminated meningococcal infection associated with sexual transmission have also been described in Europe, the US and Australia². The invasive capacity of N. meningitidis is therefore not limited to its nasopharyngeal location.

Given the phylogenetic relationship between N. meningitidis and N. gonorrhoeae and their phenotypic similarities, it is necessary to establish a correct aetiological diagnosis at the species level. The classic methods used to differentiate both species were eminently biochemical. Currently, mass spectrometry (MALDI-TOF) allows us to discriminate between both species. Although the isolation of greyish, oxidase and catalase positive colonies in culture of urogenital samples suggests infection by N. gonorrhoeae, N. meningitidis must be taken into account given the possible repercussions.

Three main ways for N. meningitidis to reach the genital mucosa have been proposed: sexual transmission, orogenital transmission, and autoinoculation from the upper respiratory tract^2,5,6. The possibility of sexual abuse should not be ruled out⁷. In the case that we present, the origin of the infection could not be identified, since the oropharyngeal swab was negative on two occasions and no samples were taken in the patient’s immediate environment.

There is a question as to whether vaccination against N. meningitidis would be useful for the prevention of urogenital infection. The ability of N. meningitidis to adapt to the urogenital mucosa may lead to loss of the polysaccharide capsule or a change in the expressed serogroup, the target of existing vaccines. Our patient was up to date on her vaccination schedule (including vaccines against serogroups B and C)². More studies would be necessary to establish the most appropriate public health service measures for the prevention of this type of infection.

Currently, there are no clinical guidelines or bibliography that support the preferential use of a specific antibiotic. In the case we present, the patient was treated with amoxicillin/clavulanic acid, and responded favourably.