First description of a rifampicin-resistant Neisseria meningitidis serogroup Y strain causing recurrent invasive meningococcal disease in Hungary.

A Hungarian soldier previously immunized against Neisseria meningitidis by quadrivalent polysaccharide vaccine was twice infected with meningococci within six weeks. The patient was treated with ceftriaxone during both episodes and he successfully recovered. His close contacts received rifampicin prophylaxis. An investigation was performed to characterize the genetic background of the pathogens to ascertain if the recurrent invasive meningococcal disease was caused by the same strain and to find out the reason for reinfection. Both meningococci belonged to the fine type Y:P1.5-2,10-1:F4-1:ST-23. This is the first description of the Europe-wide prevalent N. meningitidis serogroup Y in Hungary. In the first episode, we found wild-type rpoB allele in the non-culturable sample implying the susceptibility to rifampicin. The culturable isolate from the second episode proved resistant to rifampicin and had a point mutation in the rpoB gene. The rifampicin resistance might have evolved during the prophylactic treatment of contacts. Previous immunization of the patient with polysaccharide vaccine was ineffective due to his immunodeficiency, thus immunization with conjugate vaccine was proposed. We have proposed the implementation of centralized rifampicin susceptibility testing of N. meningitidis strains within a defined time frame to intervene and administer appropriate prophylaxis to close contacts.