缩短肺炎链球菌和流感嗜血杆菌的纸片扩散孵育时间，以减少药敏报告时间。
Short incubation of disc diffusion for Streptococcus pneumoniae and Haemophilus influenzae to reduce time to susceptibility report.
机构信息
Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
Division of Clinical Microbiology, Linköping University Hospital, Linköping, Sweden.
出版信息
J Antimicrob Chemother. 2023 Oct 3;78(10):2563-2571. doi: 10.1093/jac/dkad272.
BACKGROUND
Rapidly instituted antimicrobial therapy is important in severe infections, and reduced time to the antimicrobial susceptibility testing (AST) report is thus of importance. Disc diffusion (DD) is a cheap, rapidly adaptable, flexible and comprehensive method for phenotypic AST. Previous studies have shown that early reading of inhibition zones for non-fastidious species is possible.
OBJECTIVES
To evaluate zone reading after short incubation of DD in Haemophilus influenzae (n = 73) and Streptococcus pneumoniae (n = 112).
METHODS
The readability was evaluated and susceptibility interpretation (SIR) was performed, using the EUCAST 18 ± 2 h incubation breakpoint table (version 12.0), after 6 and 8 h of incubation. Categorical agreement (CA) and error rates were calculated using standard DD and broth microdilution as reference.
RESULTS
The proportion of readable zones in H. influenzae was 19% (6 h) and 89% (8 h). The CA was 98% after 8 h. The corresponding readability in S. pneumoniae was 63%/98% and CA was 95%/97% after 6 and 8 h, respectively. Early reading of the screening discs (benzylpenicillin 1 unit in H. influenzae and oxacillin 1 µg in S. pneumoniae) correctly identified 18/22 of the H. influenzae isolates and all the readable S. pneumoniae isolates with reduced β-lactam susceptibility. For non-β-lactam agents, very major errors were most common for quinolones in S. pneumoniae. Introduction of areas of technical uncertainty (ATUs) reduced the error rate to ≤1.1%.
CONCLUSIONS
We conclude that shortened incubation is feasible for H. influenzae and S. pneumoniae. To reduce the risk of false categorization a buffer zone (i.e. ATU) near the breakpoints must be used.
背景
在严重感染中，及时进行抗菌治疗至关重要，因此，缩短获得抗菌药物敏感性检测（AST）报告的时间非常重要。纸片扩散法（DD）是一种廉价、快速适应、灵活且全面的表型 AST 方法。先前的研究表明，对于非苛养菌，可以进行早期读取抑菌圈。
目的
评估流感嗜血杆菌（n=73）和肺炎链球菌（n=112）的 DD 短孵育后进行的抑菌圈读取。
方法
使用 EUCAST 18±2 h 孵育折点表（版本 12.0），在 6 和 8 h 孵育后评估可读取性，并进行药敏判断（SIR）。使用标准 DD 和肉汤微量稀释法作为参考，计算分类一致性（CA）和错误率。
结果
在流感嗜血杆菌中，可读抑菌圈的比例分别为 19%（6 h）和 89%（8 h）。8 h 后 CA 为 98%。在肺炎链球菌中，相应的可读率为 63%/98%，CA 分别为 6 h/95%和 8 h/97%。早期读取筛选药敏纸片（流感嗜血杆菌中苯唑西林 1 单位和肺炎链球菌中苯唑西林 1 µg）正确识别了 18/22 株流感嗜血杆菌分离株和所有具有降低β-内酰胺类药物敏感性的可读肺炎链球菌分离株。对于非β-内酰胺类药物，肺炎链球菌中喹诺酮类药物的主要错误率最高。引入技术不确定区（ATU）可将错误率降低至≤1.1%。
结论
我们得出结论，缩短孵育时间对于流感嗜血杆菌和肺炎链球菌是可行的。为了降低错误分类的风险，必须在折点附近使用缓冲区（即 ATU）。
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