To evaluate the clinical and bacteriological features of pneumococcal meningitis in pediatric and adult patients from Lima before and after the introduction of conjugate pneumococcal vaccines (PCV). 

The introduction of PCVs has significantly decreased the prevalence of invasive disease. However, the distribution of new serotypes in the post-vaccine era may influence the clinical presentations and antibiotic resistance patterns of new meningitis cases.

A secondary database analysis was conducted on patients with confirmed pneumococcal meningitis, defined by isolation of S. pneumoniae from CSF or a positive blood culture with neurological signs and symptoms. Data were obtained from three passive surveillance studies of invasive pneumococcal disease (IPD) in Lima:  IPD1 [2006-2008, pre-PCV7]; IPD2 [2009-2011, post-PCV7] and IPD3 [2016-2019, post-PCV13]. 

A total of 120 patients with pneumococcal meningitis were included (41 from IPD1, 35 from IPD2 and 44 from IPD3).  60% of the cases involved males; 63% were pediatric patients, with infants (<2y) representing 63%. 14 patients were vaccinated and 84 did not receive any vaccine. The lethality was 36% (32/88), among which 44% were infants and 28% adults (18- 60y). Penicillin resistance increased from 45% (IPD1) to 66% (IPD3), with an overall 54% resistance among adults and 51% among children. Non-susceptibility to ceftriaxone remained high, 23%, 21% and 14% across studies; with an overall 12% resistance in adults and 23% in pediatric patients. Serotypes 14 and 19F disappeared in the post-PCV13 study, with their prevalence dropping from 22% and 15% (pre-PCV7) to 0% (post-PCV13), respectively; similarly, serotype 6B decreased from 22% to 2%. Conversely, serotypes 6C and 19A  emerged with 0% and 7% (pre-PCV7)  to 18% and 11% (post-PCV13). 

Despite PCV introduction in Peru, pneumococcal meningitis remains associated with high lethality and resistance to penicillin and ceftriaxone persists, highlighting the need to continue surveillance studies to monitor antimicrobial resistance and serotype distribution.