Conjunctivitis Secondary to Neisseria meningitidis: A Potential Vertical Transmission Pathway

Abstract

The recent article by Gupta et al 1 describes presentation of conjunctivitis secondary to Neisseria meningitidis infection in a previously healthy 4-mounth-old boy. The authors stated that “Primary meningococcal conjunctivitis is presumably due to direct inoculation of N meningitidis into the conjunctival sac from an exogenous source, either airborne or manual.” Nevertheless, the authors failed to explore a potential vertical transmission pathway. N meningitidis, an obligate commensal of humans, normally colonizes the mucosa of the upper respiratory tract without affecting the host, a phenomenon known as carriage. In addition, because N meningitidis is a strict human pathogen and most patients have not been in contact with other cases, asymptomatic carries are presumably the major source of the pathogenic strains. Classically, N meningitidis spreads from person to person by airborne droplets or direct physical contact such as kissing. However, there have been relevant changes in the epidemiological behavior of N meningitidis nowadays, and the human nasopharynx is no longer the only recognized primary site of the initial step of neisserial infection. Indeed, the bacterial pathogen N meningitidis has been found in atypical sites, such as the mucous membranes of the endocervix, conjunctiva, urethra, and anus. The power of meningococcal pathogen to colonize these atypical mucous sites is potentially associated with orogenital sex or vertical transmission. In fact, orogenital contact has become a critical pathway for the transport of meningococci from the habitual nasopharyngeal habitat to the genital organs. Therefore, meningococcal transmission can occur initially via orogenital contact and, subsequently, mother to infant transmission may occur when mothers colonized with meningococci infect their babies as they are born vaginally. Colonization is a key step in the sequence of events leading to neisserial infection. In general, meningococcal infection occurs less than 10 days after colonization. However, there have been cases of neisserial infection following a prolonged period of carriage with a pathogenic strain. Now, the increase of orogenital practice has posed a new epidemiological challenge, and although meningococci have been implicated in various conjunctival disturbances, they have typically been unexplored and overlooked as potential etiological factors in such clinical events.