Neisseria macacae pneumonia in a patient with spinal cord injury: a case report

Although Neisseria macacae has been recognized as a commensal of macaque oral flora since 1983, its involvement in human disease remains remarkably uncommon. Prior literature documented fewer than a handful of infections, ranging from reddish rash, bacteremia to invasive conditions such as endocarditis and peritonitis. Strikingly, the respiratory system has not been reported as a site of infection. We first reported a case of pneumonia due to N. macacae.

A 60-year-old male developed pneumonia during treatment for a cervical spine fracture complicated by spinal cord injury. N. macacae was isolated from sputum culture and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA gene sequence analysis. The strain exhibited non-susceptible to third-generation cephalosporins but susceptible to carbapenems. Meropenem was administered, leading to a favorable response and significant improvement after one week, resulting in recovery and discharge 14 days later. No recurrence was observed during a follow-up visit one month post-discharge.

This case represents the first documented report of N. macacae-associated pneumonia, expanding the known clinical spectrum of this macaque commensal into the human respiratory tract under conditions of impaired clearance. This finding highlights the necessity of enhanced clinical-laboratory collaboration. Furthermore, the strain's atypical antimicrobial resistance profile underscores the critical importance of comprehensive susceptibility testing to guide targeted therapy and inform empirical treatment strategies in similar clinical scenarios.