BACKGROUND Blastomycosis is an environmentally acquired fungal infection that can result in severe pulmonary illness and high hospitalization rates. In 2023, a blastomycosis outbreak was detected among workers at a paper mill in Delta County, Michigan. METHODS We included patients with clinical and laboratory evidence of blastomycosis who had spent ≥40 hours in Delta County since September 1, 2022 and had illness onset December 1, 2022-July 1, 2023. We assessed epidemiological and clinical features of patients and evaluated factors associated with hospitalization. We performed whole-genome sequencing to characterize genetic relatedness of clinical isolates from eight patients. RESULTS In total, 131 patients were identified; all had worked at or visited the mill. Sixteen patients (12%) were hospitalized; one died. Compared with non-hospitalized patients, more hospitalized patients had diabetes (p=0.03) and urine antigen titers above the lower limit of quantification (p<0.001). Hospitalized patients were also more likely to have had ≥1 healthcare visits before receiving a blastomycosis diagnostic test (p=0.02) and to have been treated with antibiotics prior to antifungal prescription (p=0.001). All sequenced isolates were identified as Blastomyces gilchristii and clustered into a distinct outbreak cluster. CONCLUSIONS This was the largest documented blastomycosis outbreak in the United States. Epidemiologic evidence indicated exposures occurred at or near the mill, and genomic findings suggested a common exposure source. Patients with diabetes may have increased risk for hospitalization, and elevated urine antigen titers could indicate greater disease severity. Early suspicion of blastomycosis may prompt earlier diagnosis and treatment, potentially reducing unnecessary antibiotic prescriptions and improving patient outcomes.

中文翻译：

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密歇根州一家造纸厂大型芽生菌病暴发的流行病学和临床特征。


背景 芽生菌病是一种环境获得性真菌感染，可导致严重的肺部疾病和高住院率。2023 年，在密歇根州三角洲县一家造纸厂的工人中发现了芽生菌病疫情。方法 我们纳入了自 2022 年 9 月 1 日起在 Delta 县停留 ≥40 小时并在 2022 年 12 月 1 日至 2023 年 7 月 1 日发病的具有芽生菌病临床和实验室证据的患者。我们评估了患者的流行病学和临床特征，并评估了与住院相关的因素。我们进行了全基因组测序，以表征 8 例患者临床分离株的遗传相关性。结果 共确定了 131 例患者;他们都曾在工厂工作或参观过。16 例患者 （12%） 住院;一人死亡。与非住院患者相比，更多的住院患者患有糖尿病 （p=0.03） 且尿抗原滴度高于定量下限 （p<0.001）。住院患者在接受芽生菌病诊断试验之前也更有可能进行 ≥1 次医疗保健就诊 （p=0.02），并且在抗真菌处方前接受过抗生素治疗 （p=0.001）。所有测序的分离株均被鉴定为 Blastomyces gilchristii 并聚集到一个不同的爆发集群中。结论 这是美国记录在案的最大芽生菌病暴发。流行病学证据表明暴露发生在工厂内或附近，基因组结果表明存在共同的暴露来源。糖尿病患者住院风险可能增加，尿抗原滴度升高可能表明疾病严重程度更高。 早期怀疑芽生菌病可能会促使早期诊断和治疗，从而可能减少不必要的抗生素处方并改善患者的预后。