Environmental survival of Neisseria meningitidis

Abstract

Neisseria meningitidis is transmitted through the inhalation of large human respiratory droplets, but the risk from contaminated environmental surfaces is controversial. Compared to Streptococcus pneumoniae and Acinetobacter baumanni, meningococcal viability after desiccation on plastic, glass or metal surfaces decreased rapidly, but viable meningococci were present for up to 72 h. Encapsulation did not provide an advantage for meningococcal environmental survival on environmental surfaces.

Fig. 1.

(a) Survival of N. meningitidis and S. pneumoniae over 24 h after desiccation. Encapsulated strains F8229 (serogroup A), NMB (serogroup B), and FAM18 (serogroup C) were examined in parallel with non-encapsulated strains, serogroup A strain (F8239), NMB/synA::tetM (M7) and FAM18/synA::tetM (F18-M7), respectively. The survival of pneumococcal strain D39 was included for comparison. Viable colony-forming unit (c.f.u.) counts obtained from individual wells were normalized to the input c.f.u. counts, which are set as 100%. The mean values from at least five independent experiments are shown. No significant differences were observed between encapsulated and non-encapsulated meningococcal strains by Student's t test. (b) Survival over 72 h after desiccation. Encapsulated meningococcal strains NMB and FAM18 were examined in parallel with S. pneumoniae strain D39 and A. baumannii strain M2. The mean values and standard deviations of viable c.f.u. counts at each time point from five independent experiments are plotted. A. baumannii survived significantly better than S. pneumoniae and N. meningitidis as calculated by Student's t test (P < 0·05).