Rania A El-Kady, Ahd A Mansour, Mohamed Y Yousef
Ciprofloxacin resistance was prevalent among Gram-negative osteomyelitis cases and was associated with greater surgical complexity and poorer clinical outcomes. Early identification of ciprofloxacin-resistant infections and integration of clinical and inflammatory markers may support risk stratification and therapeutic decision-making. Given the retrospective, observational, single-center design, these findings should be interpreted cautiously and validated in larger multicenter studies.
BACKGROUND: Ciprofloxacin resistance among Gram-negative bacteria causing osteomyelitis is an emerging clinical concern that may negatively influence disease severity and patient outcomes. This study sought to assess the burden, independent predictors, and clinical impact of ciprofloxacin resistance in acute Gram-negative osteomyelitis.
METHODS: A retrospective analysis was performed on patients with acute Gram-negative osteomyelitis between 2019-2024. Clinical, microbiological, laboratory, and outcome variables were compared between ciprofloxacin-resistant and susceptible cohorts. Univariable binary logistic regression analyses were performed to identify factors associated with ciprofloxacin resistance, followed by multivariable binary logistic regression analysis to identify independent predictors. Statistical significance was considered at p-value <0.05 (two-tailed).
RESULTS: Antimicrobial resistance patterns were assessed among 279 Gram-negative isolates, while clinical and outcome analyses were conducted among 256 patients. The overall prevalence of ciprofloxacin resistance was 54.5% among Gram-negative isolates. In the univariable binary logistic regression analysis, ciprofloxacin resistance was significantly associated with chronic heart disease (p = 0.03), lower hemoglobin concentration (p = 0.04), hypoalbuminemia (p = 0.0001), and increased inflammatory biomarkers, including c-reactive protein (CRP; p = 0.001), and neutrophil-to-lymphocyte ratio (NLR; p = 0.04). Osteomyelitis caused by ESBL-producing pathogens was also significantly associated with ciprofloxacin resistance (OR = 3.93, 95% CI: 1.87-8.31; p = 0.0001). In the multivariable analysis, hypoalbuminemia (adjusted odds ratio [AOR] = 0.53, 95% confidence interval [CI]: 0.35-0.79; p = 0.002) and infection with ESBL-producing pathogens (AOR = 0.25, 95% CI: 0.11-0.54; p = 0.0001) remained independently associated with ciprofloxacin resistance. Compared with ciprofloxacin-susceptible cohort, ciprofloxacin-resistant patients required significantly more surgical debridement (p = 0.006) and developed higher rates of chronic osteomyelitis (p = 0.005), septic shock (p = 0.03), and in-hospital mortality (p = 0.02).
CONCLUSION: Ciprofloxacin resistance was prevalent among Gram-negative osteomyelitis cases and was associated with greater surgical complexity and poorer clinical outcomes. Early identification of ciprofloxacin-resistant infections and integration of clinical and inflammatory markers may support risk stratification and therapeutic decision-making. Given the retrospective, observational, single-center design, these findings should be interpreted cautiously and validated in larger multicenter studies.