Pneumococcal bacteraemia in adults over a 10-year period (2011-2020): a clinical and serotype analysis

Clinton M G Colaco; Matthew O'Sullivan; Hayden Zhang; Danica Huynh; Vitali Sintchenko; Shahin Oftadeh; Gwendolyn L Gilbert; Ravindra Dotel

doi:10.1111/imj.16045

Pneumococcal bacteraemia in adults over a 10-year period (2011-2020): a clinical and serotype analysis

Intern Med J. 2023 Mar 5. doi: 10.1111/imj.16045. Online ahead of print.

Authors

Clinton M G Colaco^{1

2

3}, Matthew O'Sullivan^{4

5

6}, Hayden Zhang¹, Danica Huynh¹, Vitali Sintchenko^{5

7

8}, Shahin Oftadeh⁹, Gwendolyn L Gilbert⁵, Ravindra Dotel¹⁰

Affiliations

¹ Centre for Infectious Diseases and Microbiology, Westmead Hospital, Sydney, New South Wales, Australia.
² The University of Sydney, Westmead Clinical School, Sydney, New South Wales, Australia.
³ Griffith University, School of Medicine and Dentistry, Southport, Queensland, Australia.
⁴ Centre for Infectious Diseases and Microbiology Laboratory Services, New South Wales Health Pathology-Institute of Clinical Pathology and Medical Research, Westmead Hospital, Sydney, New South Wales, Australia.
⁵ Westmead Institute for Medical Research, Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, New South Wales, Australia.
⁶ NSW Health Pathology, Sydney, New South Wales, Australia.
⁷ Centre for Infectious Diseases and Microbiology - Public Health, Westmead Hospital, Sydney, New South Wales, Australia.
⁸ NSW Invasive Pneumococcal Disease Reference Laboratory, Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Sydney, New South Wales, Australia.
⁹ Centre for Infectious Diseases and Microbiology Laboratory Services, NSW Invasive Pneumococcal Disease Reference Laboratory, Institute of Clinical Pathology and Medical Research, NSW Health Pathology, Sydney, New South Wales, Australia.
¹⁰ Department of Infectious Diseases, Blacktown Hospital, Sydney, New South Wales, Australia.

PMID: 36872866
DOI: 10.1111/imj.16045

Abstract

Background: Streptococcus pneumoniae (pneumococcus) is a human nasopharyngeal tract coloniser responsible for invasive pneumococcal disease, which is largely vaccine preventable. Vaccination is recommended from birth for all, and through adulthood for those with risk conditions.

Aims: To describe the clinical and serotype analysis of pneumococcus bacteraemia over a 10-year period.

Methods: A 10-year (February 2011-December 2020) retrospective review was performed on all adult (age ≥18 years) pneumococcus bacteraemia presenting to the four public hospitals in Western Sydney, Australia. Comorbidities and risk factors were recorded.

Results: Three hundred unique episodes of S. pneumoniae bloodstream infection (SPBI) were identified during the study period. The median age for SPBI was 63 years with 31.7% aged 70 years or older. A 94.7% had one or more risks factors for SPBI. Pneumonia was reported in 80% of all SPBI, whereas meningitis was reported in 6% and infective endocarditis in <1%. Asplenia was noted in 2.4%. Seven- and 30-day mortality was 6.6% and 11.9%, with a higher 30-day mortality in those aged ≥70 years (24.4%). The serotype distribution showed 7-valent conjugate vaccine covered 11.0% of all isolates, whereas 13-valent conjugate vaccine (13vPCV) and a 23-valent polysaccharide vaccine (23vPPV) covered 41.7% and 69.0% respectively. Immunisation details were available for 110 individuals, of whom, only 7.3% had received pneumococcal vaccination.

Conclusions: Most patients with pneumococcal bacteraemia had age- or comorbidity-related risk factors but were not vaccinated. Two-thirds of cases occurred in people aged <70 years. 13vPCV and 23vPPV covered 41.7% and 69.0% of bacteraemic isolates.

Keywords: Streptococcus pneumoniae; immunisation; pneumococcal; pneumococcal infections; pneumonia; vaccines.