Fluoroquinolone Regimens Linked to Higher Treatment Failure in Human Brucellosis

A systematic review and meta-analysis published in PLOS Neglected Tropical Diseases finds that fluoroquinolone-based antibiotic regimens performed worse than standard doxycycline-based combinations in the treatment of human brucellosis. The analysis, registered prospectively in PROSPERO, pooled data from nine clinical studies comprising 602 patients and found a significantly higher risk of therapeutic failure with fluoroquinolone-containing therapy, along with a longer time to fever resolution.

Brucellosis is a major zoonotic infection worldwide, with the highest burden reported in the Mediterranean region. The therapeutic role of fluoroquinolones in the disease has remained controversial, motivating the authors to compare fluoroquinolone-based regimens with conventional therapies such as doxycycline combined with streptomycin or rifampicin. The review followed PRISMA recommendations and searched PubMed, Scopus, Web of Science, and the Cochrane Library for randomized controlled trials published through August 2025. The main outcomes were therapeutic failure, relapse, adverse events, and time to defervescence, analyzed in STATA v18 to compute pooled risk ratios and mean differences with 95% confidence intervals. Risk of bias was assessed with the RoB 2 tool and certainty of evidence with the GRADE method.

The headline result concerned treatment failure. Compared with standard regimens, fluoroquinolone-based therapy was associated with a significantly higher risk of therapeutic failure, with a pooled risk ratio of 2.11 (95% CI 1.26–3.51; P = 0.004). The risk of relapse was also higher, at a risk ratio of 1.88 (95% CI 0.94–3.74), but this did not reach statistical significance (P = 0.07). No statistically significant between-study heterogeneity was observed for either outcome, with I² values of 0%.

Subgroup analyses showed a significantly increased risk of therapeutic failure among patients with uncomplicated brucellosis and in studies with treatment durations longer than eight weeks, although the differences between subgroups themselves were not statistically significant. On safety, the analysis found no statistically significant difference in adverse events between fluoroquinolone-based and standard regimens under the random-effects model (RR = 0.62, 95% CI 0.29–1.33; P = 0.22). The point estimate favored the fluoroquinolone regimens, but the confidence interval included the null effect, so no safety advantage can be claimed.

Fluoroquinolone-based regimens were also associated with a significantly longer time to defervescence than standard regimens, with a mean difference of 1.20 days (95% CI 0.66–1.74; P < 0.001). According to the GRADE evaluation, the certainty of evidence was moderate for therapeutic failure and time to defervescence, and low for relapse and adverse events, reflecting limitations in the underlying trial evidence.

The authors conclude that, compared with conventional doxycycline-based combinations, fluoroquinolone-based regimens were associated with a higher risk of therapeutic failure and a longer time to fever resolution, while relapse risk did not differ significantly. They state that these findings do not support the routine use of fluoroquinolones as first-line therapy for adult brucellosis, and that further well-designed randomized controlled trials are needed.

Subject of Research: Efficacy and safety of fluoroquinolone-based regimens versus standard therapy for human brucellosis

Article Title: Efficacy and safety of fluoroquinolones in the treatment of human brucellosis: A systematic review and meta-analysis

Article References: Mohammadi-Sartang, M., Rafieipour, N., Afrasiabian, S., Mahmoudi, R., Moradi, Y., Karimi, M., & Servatyari, K. (2026). Efficacy and safety of fluoroquinolones in the treatment of human brucellosis: A systematic review and meta-analysis. PLOS Neglected Tropical Diseases, 20(10), e0013822. https://doi.org/10.1371/journal.pntd.0013822

Image Credits: AI Generated

DOI: 10.1371/journal.pntd.0013822

Keywords: brucellosis, fluoroquinolones, meta-analysis, systematic review, therapeutic failure, doxycycline, antibiotic therapy, randomized controlled trials, GRADE, adverse events, Efficacy, safety