Large Cluster of Neisseria meningitidis Urethritis in Columbus, Ohio, 2015

Abstract

Background: Neisseria meningitidis (Nm) is a Gram-negative diplococcus that normally colonizes the nasopharynx and rarely infects the urogenital tract. On Gram stain of urethral exudates, Nm can be misidentified as the more common sexually transmitted pathogen Neisseria gonorrhoeae.

Methods: In response to a large increase in cases of Nm urethritis identified among men presenting for screening at a sexually transmitted disease clinic in Columbus, Ohio, we investigated the epidemiologic characteristics of men with Nm urethritis and the molecular and phylogenetic characteristics of their Nm isolates. The study was conducted between 1 January and 18 November 2015.

Results: Seventy-five Nm urethritis cases were confirmed by biochemical and polymerase chain reaction testing. Men with Nm urethritis were a median age of 31 years (interquartile range [IQR] = 24-38) and had a median of 2 sex partners in the last 3 months (IQR = 1-3). Nm cases were predominantly black (81%) and heterosexual (99%). Most had urethral discharge (91%), reported oral sex with a female in the last 12 months (96%), and were treated with a ceftriaxone-based regimen (95%). A minority (15%) also had urethral chlamydia coinfection. All urethral Nm isolates were nongroupable, ST-11 clonal complex (cc11), ET-15, and clustered together phylogenetically. Urethral Nm isolates were similar by fine typing (PorA P1.5-1,10-8, PorB 2-2, FetA F3-6), except 2, which had different PorB types (2-78 and 2-52).

Conclusions: Between January and November 2015, 75 urethritis cases due to a distinct Nm clade occurred among primarily black, heterosexual men in Columbus, Ohio. Future urogenital Nm infection studies should focus on pathogenesis and modes of sexual transmission.

Keywords: Gram stain; Neisseria gonorrhoeae; Neisseria meningitidis; urethritis.

Figure 1.

Number of male patients with confirmed Neisseria meningitidis or Neisseria gonorrhoeae urethritis, Columbus, Ohio, January 1–November 18, 2015 (n = 372). *Through November 18 only. Abbreviations: GC, Neisseria gonorrhoeae; Nm, Neisseria meningitidis.

Figure 2.

Configuration of the capsule locus (cps) in the nongroupable Neisseria meningitidis urethral isolates (Columbus, Ohio). An 843-bp insertion element (IS1301) was present in the intergenic region linking the ctr and css operons with simultaneous deletion of cssABC genes and partial csc (5’-region) (dotted line). Abbreviations: ctrG, capsule surface translocation gene; csc, serogroup C capsule polymerase (polysialyltransferase) gene; cssA-C, sialic-acid capsule biosynthesis genes; cssE, O-acetyltransferase gene; ctrA-D, capsule transport genes.

Figure 3.

Phylogenetic placement of nongroupable Neisseria meningitidis (Nm) urethral isolates (Columbus, Ohio) among closely related Nm cc11 isolates. Previously published isolates are labeled according to disease type, serogroup, country, and year of isolation, with isolate name and PubMLST identifier in parentheses. Asterisks indicate that the year of isolation was not available for a published genome sequence. Isolates from this study are labeled by their month of isolation in 2015. Isolates on branches representing fewer than 10^–5 substitutions per site are grouped with others from the same month, and their count is reported in brackets. The phylogeny is inferred from a 1.45-megabase core genome alignment and rooted on the remainder of Nm cc11. Branches with bootstrap support <80% were collapsed, with unlabeled branches having 100% bootstrap support (400 replicates). Abbreviation: NG, nongroupable.