{"doi":"10.1093/infdis/jiae453","title":"Increased Proportions of Invasive Pneumococcal Disease Cases Among Adults Experiencing Homelessness Sets the Stage for New Serotype 4 Capsular-Switch Recombinants","abstract":"BACKGROUND: The Centers for Disease Control and Prevention's Active Bacterial Core surveillance (ABCs) identified increased serotype 4 invasive pneumococcal disease (IPD), particularly among adults experiencing homelessness (AEH). METHODS: We quantified increased proportions of IPD cases in AEH during 2016-2022. Employing genomic-based characterization of IPD isolates, we identified serotype-switch variants. Recombinational analyses were used to identify the genetic donor and recipient strain that generated a serotype 4 progeny strain. We performed phylogenetic analyses of the serotype 4 progeny and of the serotype 12F genetic recipient to determine genetic distances. RESULTS: We identified a cluster of 30 highly related (0-21 nucleotide differences) IPD isolates recovered during 2022-2023, corresponding to a serotype 4 capsular-switch variant. This strain arose through a multifragment recombination event between serotype 4/ST10172 and serotype 12F/ST220 parental strains. Twenty-five of the 30 cases occurred in Oregon. Of 29 cases with known residence status, 16 occurred in AEH. Variant emergence coincided with a 2.6-fold increase (57 to 148) of cases caused by the serotype 4/ST10172 donor lineage in 2022 compared to 2019 and its first appearance in Oregon. Most serotypes showed sequential increases of AEH IPD/all IPD ratios during 2016-2022 (eg, for all serotypes combined, 247/2198, 11.2% during 2022 compared to 405/5317, 7.6% for 2018-2019, P < .001). Serotypes 4 and 12F each caused more IPD than any other serotype in AEH during 2020-2022 (207 combined case isolates accounting for 38% of all IPD in AEH). CONCLUSIONS: Expansion and increased transmission of serotypes 4 and 12F among adults potentially led to recent genesis of an impactful hybrid serotype-switch variant.","journal":"The Journal of Infectious Diseases","year":2024,"id":441118,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":9,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9581,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":281653,"name":"Sopio Chochua","orcid":"0000-0001-8222-7353","position":1,"is_corresponding":false},{"id":459654,"name":"Ben Metcalf","orcid":"0000-0002-4945-3217","position":2,"is_corresponding":false},{"id":1254177,"name":"Wuling Lin","orcid":null,"position":3,"is_corresponding":false},{"id":325537,"name":"Theresa Tran","orcid":"0000-0002-5247-7797","position":4,"is_corresponding":false},{"id":281654,"name":"Zhongya Li","orcid":"0000-0003-1247-2059","position":5,"is_corresponding":false},{"id":325538,"name":"Yuan Li","orcid":"0000-0002-2331-2694","position":6,"is_corresponding":false},{"id":947828,"name":"Meghan L. Bentz","orcid":"0000-0001-9432-5858","position":7,"is_corresponding":false},{"id":324681,"name":"Mili Sheth","orcid":null,"position":8,"is_corresponding":false},{"id":863105,"name":"Gunars Osis","orcid":"0000-0002-0613-737X","position":9,"is_corresponding":false},{"id":228835,"name":"Lesley McGee","orcid":"0000-0001-8214-921X","position":10,"is_corresponding":false},{"id":281658,"name":"Bernard Beall","orcid":"0000-0001-5315-1070","position":0,"is_corresponding":true}],"reference_count":35,"raw_metadata":null,"created_at":"2026-07-19T02:01:06.281460Z","pmid":"39259351","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}