Antimicrobial Sensitivity Testing Using the Kirby-Bauer Disk Diffusion Method; Limited Utility in Ugandan Hospitals

Background: Antimicrobial resistance (AMR) is a global health threat responsible for increased healthcare costs and mortality. The World Health Organization (WHO) global action plan on AMR recommends antimicrobial sensitivity testing (AST) and surveillance of antibiotic use to address this threat. We conducted a cross-sectional study to determine the utility of AST in three major referral hospitals in Uganda. Methods: We used abstraction checklists to collect data on AST requests, AST performed, AST turnaround time, and dispensed antibiotics, from in-patient files and laboratory and pharmacy records. Antibiotic data were summarized using proportions. The relationship between dispensed antibiotics and AST antibiotic-disks was analyzed using spearman’s rank correlation and simple linear regression. Results: Of the 607 in-patient files reviewed, AST was requested in 24 (4.0%), and done in 13 (2.1%). All three hospitals used the Kirby-Bauer disk diffusion method for AST, with a median turnaround time of 5 days (IQR 4-8). While the frequently used AST antibiotic-disks were cotrimoxazole (13.0%), ampicillin (11.7%), and ceftriaxone (10.5%), the most dispensed antibiotics were metronidazole (30.3%), amoxicillin (19.6%) and ceftriaxone (14.8%). There was a weak correlation (r=0.313, p=0.120) between dispensed antibiotics and AST antibiotic-disks, and AST performance was not associated with antibiotic consumption. Conclusion: We report an underutilization of AST, inconsistent with the hospital antibiotic consumption, and may be related to the use of the disk diffusion method. We recommend alternative faster and better coordination in the procurement of AST diagnostics in Ugandan hospitals.

研究背景：抗菌药物耐药性（Antimicrobial Resistance, AMR）是一项全球性公共卫生威胁，可导致医疗成本上升与死亡率升高。世界卫生组织（World Health Organization, WHO）发布的抗菌药物耐药性全球行动计划建议，开展抗菌药物敏感性试验（Antimicrobial Sensitivity Testing, AST）并对抗生素使用情况进行监测，以应对这一威胁。本研究针对乌干达三家大型转诊医院开展横断面研究，旨在评估抗菌药物敏感性试验的应用价值。

研究方法：本研究通过数据提取清单，从住院患者病历、实验室及药房记录中收集抗菌药物敏感性试验申请情况、试验执行情况、试验周转时长以及配发抗生素相关数据。抗生素相关数据以构成比进行汇总分析；采用斯皮尔曼等级相关分析与简单线性回归，探究配发抗生素与抗菌药物敏感性试验所用抗生素药敏纸片之间的关联。

研究结果：本次共审阅607份住院患者病历，其中24份（4.0%）提交了抗菌药物敏感性试验申请，13份（2.1%）完成了该项试验。三家医院均采用柯赫-鲍尔纸片扩散法（Kirby-Bauer disk diffusion method）开展抗菌药物敏感性试验，试验周转时长的中位数为5天（四分位距4~8天）。本研究中抗菌药物敏感性试验最常用的药敏纸片依次为复方新诺明（13.0%）、氨苄西林（11.7%）与头孢曲松（10.5%）；而临床配发量最高的抗生素则为甲硝唑（30.3%）、阿莫西林（19.6%）与头孢曲松（14.8%）。配发抗生素与抗菌药物敏感性试验药敏纸片使用情况之间仅存在弱相关性（r=0.313，p=0.120），且抗菌药物敏感性试验的执行情况与抗生素消耗量无显著关联。

研究结论：本研究发现乌干达医院的抗菌药物敏感性试验应用不足，且其使用情况与医院抗生素消耗量并不匹配，这一现象可能与纸片扩散法的应用有关。本研究建议乌干达医院采用更快速的替代检测方案，并在抗菌药物敏感性试验诊断试剂的采购环节优化协调机制。