Targeting tularemia : clinical, laboratory, and treatment outcomes from an 11-year retrospective observational cohort in northern sweden

• Published in: Clinical Infectious Diseases
• Main Authors: Plymoth, Martin, Lundqvist, Robert, Nystedt, Anders, Sjöstedt, Anders, Gustafsson, Tomas N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: UmeÃ¥ universitet, Institutionen för klinisk mikrobiologi 2024
• Subjects: Francisella tularensis; doxycycline; ciprofloxacin; treatment; outcome; Infectious Medicine; Infektionsmedicin; Northern Sweden; Norrbotten
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-222845; https://doi.org/10.1093/cid/ciae098

Background: Tularemia is an important re-emerging disease with a multimodal transmission-pattern. Treatment outcomes of current recommended antibiotic regimens (including ciprofloxacin and doxycycline) remain unclear. In this retrospective cohort study, we report clinical, laboratory, geographical, and treatment outcomes of laboratory-confirmed tularemia cases over an 11-year period in Northern Sweden. Methods: Data from reported tularemia cases (aged >10 years at time of study) in Norrbotten county between 2011-2021 were collected through review of electronic medical records and participant questionnaires; with 415 out of 784 accepting participation (52.9%). Of these, 327 were laboratory-confirmed cases (serology and/or PCR). A multivariable logistic regression model was used to investigate variables associated with re-treatment. Results: Median age of participants was 54 years (IQR 41.5-65) and 49.2% were female. While ulceroglandular tularemia was the predominant form (n=215, 65.7%), there were several cases of pulmonary tularemia (n=40; 12.2%). Inflammatory markers were largely non-specific, with monocytosis frequently observed (n=36/75; 48%). Tularemia was often misdiagnosed upon presentation (n=158, 48.3%), with 65 (19.9%) receiving initial inappropriate antibiotics, and 102 (31.2%) re-treated. Persistent lymphadenopathy was infrequent (n=22, 6.7%), with 10 undergoing surgical interventions. In multivariable analysis of variables associated with re-treatment, we highlight differences in time until receiving appropriate antibiotics (8 [IQR 3.25-20.75] vs. 7 [IQR 4-11.25] days; adjusted p=0.076), and doxycycline-based treatment regimen (vs. ciprofloxacin; adjusted p=0.084), although not significant after correction for multiple comparisons. Conclusion: We comprehensively summarize clinical, laboratory, and treatment outcomes of type B tularemia. Targeting tularemia requires clinical awareness, early diagnosis and timely commencement of treatment for an appropriate duration.