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Efficacy of beta-lactam monotherapy versus clindamycin or addition of metronidazole in peritonsillar abscess – an observational cohort study with a focus on Fusobacterium necrophorum

Loggarfve, Mattias ; Lindberg, Elin ; Holm, Karin LU ; Gisselsson-Solén, Marie LU orcid and Nygren, David LU orcid (2026) In Clinical Microbiology and Infection
Abstract

Objectives To compare beta-lactam monotherapy versus clindamycin or addition of metronidazole in patients with peritonsillar abscess (PTA). Methods This population-based, retrospective cohort study compared treatment with beta-lactam monotherapy (reference) with clindamycin or addition of metronidazole in patients with PTA during 2013–2020 in the Skåne region, Sweden. The primary outcome was a composite of recurrent pharyngotonsillitis or PTA within 30 days. OR and average treatment effects (ATEs) were estimated using multiple logistic regression and inverse probability weighting (IPW), respectively, with 95% CIs. After IPW, patient groups were assessed by standardized mean differences and were found to be well balanced (<0.10). The... (More)

Objectives To compare beta-lactam monotherapy versus clindamycin or addition of metronidazole in patients with peritonsillar abscess (PTA). Methods This population-based, retrospective cohort study compared treatment with beta-lactam monotherapy (reference) with clindamycin or addition of metronidazole in patients with PTA during 2013–2020 in the Skåne region, Sweden. The primary outcome was a composite of recurrent pharyngotonsillitis or PTA within 30 days. OR and average treatment effects (ATEs) were estimated using multiple logistic regression and inverse probability weighting (IPW), respectively, with 95% CIs. After IPW, patient groups were assessed by standardized mean differences and were found to be well balanced (<0.10). The primary subgroup analysis restricted the analysis to PTA caused by Fusobacterium necrophorum . Sensitivity analyses included comparing penicillin monotherapy with all other regimens and classifying treatment according to the initial empiric antibiotic, irrespective of subsequent changes. Results A total of 889 patients were included (median age 32 years [interquartile range 21–45]; 413/889 [47%] female). F. necrophorum was the most frequently identified pathogen, detected in 270 of 889 patients (30%), followed by Streptococcus pyogenes in 229 of 889 (26%) and group C/G streptococci in 48 of 889 (5%). Of 889 patients, 392 (44%) were treated with beta-lactam monotherapy (96% penicillin) and 497 (56%) were treated with clindamycin or combination therapy with metronidazole. Recurrent pharyngotonsillitis or PTA occurred in 57 of 889 (6%) overall and in 39 of 270 (14%) in the F. necrophorum subgroup. No association between antibiotic regimen and recurrence was observed in multivariable analyses (adjusted OR 1.4 [95% CI 0.8–2.5] overall and 1.0 [95% CI 0.5–2.1] in the F. necrophorum subgroup) or IPW analyses (IPW-derived ATEs 0.02 [95% CI −0.01 to 0.05] and 0.01 [95% CI −0.07 to 0.10], respectively. Findings were robust across sensitivity analyses. Conclusion Beta-lactam monotherapy of PTA was not associated with higher recurrence rates compared with broader antibiotic therapy, including among patients with F. necrophorum infection.

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organization
publishing date
type
Contribution to journal
publication status
in press
subject
keywords
Antibiotics, Fusobacterium, Peritonsillar abscess, Peritonsillitis, Streptococcus
in
Clinical Microbiology and Infection
publisher
Wiley-Blackwell
external identifiers
  • pmid:42546922
  • scopus:105048017217
ISSN
1198-743X
DOI
10.1016/j.cmi.2026.07.044
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2026 The Authors.
id
545201b5-8a96-4e19-9ec3-d2b709d06418
date added to LUP
2026-09-22 14:53:20
date last changed
2026-09-22 16:20:42
@article{545201b5-8a96-4e19-9ec3-d2b709d06418,
  abstract     = {{<p>Objectives To compare beta-lactam monotherapy versus clindamycin or addition of metronidazole in patients with peritonsillar abscess (PTA). Methods This population-based, retrospective cohort study compared treatment with beta-lactam monotherapy (reference) with clindamycin or addition of metronidazole in patients with PTA during 2013–2020 in the Skåne region, Sweden. The primary outcome was a composite of recurrent pharyngotonsillitis or PTA within 30 days. OR and average treatment effects (ATEs) were estimated using multiple logistic regression and inverse probability weighting (IPW), respectively, with 95% CIs. After IPW, patient groups were assessed by standardized mean differences and were found to be well balanced (&lt;0.10). The primary subgroup analysis restricted the analysis to PTA caused by Fusobacterium necrophorum . Sensitivity analyses included comparing penicillin monotherapy with all other regimens and classifying treatment according to the initial empiric antibiotic, irrespective of subsequent changes. Results A total of 889 patients were included (median age 32 years [interquartile range 21–45]; 413/889 [47%] female). F. necrophorum was the most frequently identified pathogen, detected in 270 of 889 patients (30%), followed by Streptococcus pyogenes in 229 of 889 (26%) and group C/G streptococci in 48 of 889 (5%). Of 889 patients, 392 (44%) were treated with beta-lactam monotherapy (96% penicillin) and 497 (56%) were treated with clindamycin or combination therapy with metronidazole. Recurrent pharyngotonsillitis or PTA occurred in 57 of 889 (6%) overall and in 39 of 270 (14%) in the F. necrophorum subgroup. No association between antibiotic regimen and recurrence was observed in multivariable analyses (adjusted OR 1.4 [95% CI 0.8–2.5] overall and 1.0 [95% CI 0.5–2.1] in the F. necrophorum subgroup) or IPW analyses (IPW-derived ATEs 0.02 [95% CI −0.01 to 0.05] and 0.01 [95% CI −0.07 to 0.10], respectively. Findings were robust across sensitivity analyses. Conclusion Beta-lactam monotherapy of PTA was not associated with higher recurrence rates compared with broader antibiotic therapy, including among patients with F. necrophorum infection.</p>}},
  author       = {{Loggarfve, Mattias and Lindberg, Elin and Holm, Karin and Gisselsson-Solén, Marie and Nygren, David}},
  issn         = {{1198-743X}},
  keywords     = {{Antibiotics; Fusobacterium; Peritonsillar abscess; Peritonsillitis; Streptococcus}},
  language     = {{eng}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Clinical Microbiology and Infection}},
  title        = {{Efficacy of beta-lactam monotherapy versus clindamycin or addition of metronidazole in peritonsillar abscess – an observational cohort study with a focus on Fusobacterium necrophorum}},
  url          = {{http://dx.doi.org/10.1016/j.cmi.2026.07.044}},
  doi          = {{10.1016/j.cmi.2026.07.044}},
  year         = {{2026}},
}