Biomedical subjects

Laura L Hammitt

Publications and source records attributed to Laura L Hammitt.

2 recordsLinked to original sources

PubMed2026

Incidence of invasive group A streptococcal infections and comparison of emm types from invasive infections, pharyngitis, and throat carriage in American Indian communities in the Southwest United States.

BACKGROUND: American Indian/Alaska Native (AI/AN) communities in the US have high rates of group A streptococcal (GAS) infections. We determined the incidence of invasive infections in AI communities in the Southwest and compared emm types from invasive infections, pharyngitis, and throat carriage. METHODS: Activities conducted in the White Mountain Apache Tribal lands (WMA) and Navajo Nation (NN) included active, laboratory-based surveillance for invasive GAS infections (WMA: 2019─2024; NN: 2023─2024; all ages); surveillance for GAS pharyngitis (2023-2024; children 0─17 years); and culture for GAS from oropharyngeal carriage samples (2019 and 2022─2023; children 0─14 years). Emm types were determined by whole-genome sequencing. Annual incidence rates were calculated using Poisson regression. RESULTS: In WMA, age-standardized rates of invasive infections ranged from 80-270/100,000 persons between 2019-2024. Predominant emm types varied (n=74 isolates): 91 (59%) and 49 (32%) in 2019-2020, and 43 (40%) and 53 (30%) in 2023. In NN, rates were 40-60/100,000 persons in 2023-2024; common emm types (n=51) were 53 (28%), 101 (18%), and 12 (16%). In WMA and NN, emm types 1, 12, and 53 predominated in pharyngitis (n=190), and 1, 12, and 91 in throat carriage (n=119). CONCLUSIONS: Rates of invasive GAS infections in these communities were 3-35 times higher than the national US average (12.2/100,000 in 2024). Emm types varied over time with limited overlap in strains from throat carriage or pharyngitis isolates and those from invasive infections. Findings support continuing GAS surveillance and engaging AI/AN communities throughout vaccine development and evaluation.

Indigenous health↗

PubMed2025

Multi-strain carriage and intrahost diversity of Staphylococcus aureus among Indigenous adults in the USA.

Staphylococcus aureus (SA) is an opportunistic pathogen and human commensal that is frequently present in the upper respiratory tract, gastrointestinal tract and skin. While SA can cause diseases ranging from minor skin infections to life-threatening bacteraemia, it can also be carried asymptomatically. Indigenous individuals in the Southwest USA experience high rates of invasive SA disease. As carriage is the most significant risk factor for disease, understanding the dynamics of SA carriage, and in particular co-carriage of multiple strains, is important to develop strategies to prevent transmission in vulnerable communities. Here, we investigated SA co-carriage and intrahost evolution by sampling several colonies from multiple anatomical sites and whole-genome sequencing (WGS) on 310 SA isolates collected from 60 Indigenous adults participating in a cross-sectional carriage study. We assessed the richness and diversity of SA isolates via differences in multilocus sequence type, core-genome SNPs and genome content. Using WGS data, we identified 95 distinct SA intra-subject lineages (ISLs) among 60 participants; co-carriage was detected in 42% (25/60). Notably, two participants each carried four distinct SA ISLs. Variation in antibiotic resistance determinants among carried strains was identified among 42% (25/60) of participants. Lastly, we found unequal distribution of clonal complex by body site, suggesting that certain lineages may be adapted to specific anatomical sites. Together, these findings suggest that co-carriage may occur more frequently than previously appreciated and further our understanding of SA intrahost diversity during carriage, which has implications for surveillance activities and epidemiological investigations.

Humans↗