Invasive Pneumococcal Strain Distributions and Isolate Clusters Associated With Persons Experiencing Homelessness...

Area of Science:

• Microbiology
• Epidemiology
• Genomics

Background:

• Invasive pneumococcal disease (IPD) remains a significant public health concern.
• Understanding circulating serotypes and their transmission patterns is crucial for disease prevention and control.

Purpose of the Study:

• To characterize invasive pneumococcal disease (IPD) isolates from a multistate US surveillance network in 2018.
• To investigate the tendency of isolates within the same serotype to form related clusters.

Main Methods:

• Whole genome sequencing was performed on 2885 IPD isolates from the CDC's Active Bacterial Core surveillance (ABCs) network.
• Phylogenetic analysis was conducted for serotypes with at least 27 isolates.

Main Results:

• Non-13-valent pneumococcal conjugate vaccine (PCV13) serotypes comprised over 70% of IPD cases.
• Serotype 3 was the most common overall IPD serotype.
• Serotypes 4, 12F, 20, and 7F showed high clustering proportions and were frequently found in isolates from persons experiencing homelessness (PEH).

Conclusions:

• Non-PCV13 serotypes are the primary drivers of IPD in the US.
• Specific serotypes, particularly those prevalent in PEH, exhibit increased clustering, indicating potential transmission networks.
• Findings highlight the need for ongoing surveillance and serotype-specific control strategies.