Hospital-onset adult invasive pneumococcal disease in Israel: Sicker patients, different pathogens

Invasive pneumococcal disease (IPD) usually has its onset in the community (CO-IPD), but it can commence following hospitalization (HO-IPD). This study compared HO-IPD and CO-IPD cases during the implementation of the pneumococcal conjugate vaccine (PCV) program for children in Israel.

This was a nationwide retrospective cohort study of adult (age >18 years) IPD patients covering the period from the implementation of the PCV7/13 program in 2009/2010 through 2015. HO-IPD and CO-IPD were defined as IPD with onset ≥4 and ≤2 days from admission, respectively. Patient characteristics, outcome measures, serotypes, and antimicrobial susceptibility were compared for the entire cohort, followed by a matched case-control analysis.

The study included 114 patients with HO-IPD and 2180 with CO-IPD. After matching HO-IPD to CO-IPD patients by age, sex, and comorbidities, the mortality rate and discharge to long-term care facility rate were significantly higher for HO-IPD patients than for CO-IPD patients (44.6% vs. 26.3% and 26.5% vs. 8.2%, respectively). HO-IPD isolates were less often covered by PCV13 (39.6% vs. 49.0%) and pneumococcal polysaccharide vaccine PPSV23 (56.6% vs. 71.3%) and more often resistant to penicillin (9.3% vs. 3.6%), ceftriaxone (3.8% vs. 0.75%), and levofloxacin (9.3% vs. 0.8%).

HO-IPD was associated with higher morbidity and mortality than CO-IPD and was more often caused by non-vaccine serotypes (primarily non-PCV13 types) and antibiotic-resistant strains.