Department of Infectious Diseases, Japanese Red Cross Maebashi Hospital, Maebashi, Japan.
Department of Microbiology, Japanese Red Cross Maebashi Hospital, Maebashi, Japan.
Microbiol Spectr. 2024 Oct 3;12(10):e0122324. doi: 10.1128/spectrum.01223-24. Epub 2024 Aug 20.
Rapid and accurate identification of (SA) in blood culture specimens is crucial for timely clinical intervention. Traditional Gram staining methods, although widely accessible and cost-effective, exhibit variable sensitivities and specificities in the BACTEC system. We aimed to develop and validate the "STAPH score," a novel semi-quantitative scoring system that integrates Gram stain morphology and time to positivity to differentiate SA from coagulase-negative staphylococci (CoNS) in blood cultures. We analyzed 148 blood culture specimens from septic patients. Each specimen was assessed independently by two examiners using Gram staining and the STAPH score, which assigns points based on five parameters: cluster size, time to positivity, aerobic enlargement, pint (three-dimensional appearance), and the presence of hemorrhage. Sensitivity and specificity were calculated for various cutoff points. Cohen's kappa coefficient was used to assess inter-examiner agreement. Of the 148 specimens, 49 (33.1%) were identified as SA and 99 (66.9%) as CoNS. At a STAPH score cutoff of 3 points, the sensitivity was 93.9% (95% confidence interval [CI], 83.1%-98.7%) and specificity was 91.9% (95% CI, 84.7%-96.4%). The kappa coefficient at this cutoff was 0.67 (95% CI, 0.55-0.79). A STAPH score <3 effectively ruled out SA with 100% sensitivity, whereas a score of 5 confirmed SA with 100% specificity. The STAPH score is a reliable and efficient tool for the rapid identification of SA in blood cultures within the BACTEC system. By combining Gram staining observations with time to positivity, this method enhances diagnostic accuracy, reduces subjectivity, and supports timely clinical decision-making.IMPORTANCEThe rapid and accurate identification of (SA) in blood cultures is vital for timely and appropriate clinical intervention. This study introduces the "STAPH score," a novel semi-quantitative scoring system that combines Gram stain morphology and time to positivity. By providing a reliable and efficient method to differentiate SA from coagulase-negative staphylococci, the STAPH score enhances diagnostic accuracy and reduces subjectivity in microscopic examinations. This score, applicable within the BACTEC system, addresses the limitations of traditional Gram staining methods and expensive molecular techniques. The implementation of the STAPH score in clinical practice can lead to faster diagnosis, improved patient outcomes, and optimized antimicrobial therapy. This method is particularly valuable in resource-limited settings where advanced diagnostic tools may not be available.
快速准确地鉴定血培养标本中的金黄色葡萄球菌（SA）对于及时的临床干预至关重要。传统的革兰氏染色方法虽然广泛可用且具有成本效益，但在 BACTEC 系统中的灵敏度和特异性存在差异。我们旨在开发和验证“STAPH 评分”，这是一种新的半定量评分系统，它将革兰氏染色形态学和阳性时间整合在一起，以区分血培养中的金黄色葡萄球菌与凝固酶阴性葡萄球菌（CoNS）。我们分析了 148 份来自脓毒症患者的血培养标本。每个标本由两名检查者独立使用革兰氏染色和 STAPH 评分进行评估，该评分根据五个参数进行评分：簇大小、阳性时间、需氧扩大、 pint（三维外观）和出血情况。计算了各种截止值的敏感性和特异性。使用 Cohen 的 kappa 系数评估检查者间的一致性。在 148 份标本中，49 份（33.1%）被鉴定为 SA，99 份（66.9%）为 CoNS。在 STAPH 评分截点为 3 分时，敏感性为 93.9%（95%置信区间[CI]，83.1%-98.7%），特异性为 91.9%（95%CI，84.7%-96.4%）。在此截止点的 kappa 系数为 0.67（95%CI，0.55-0.79）。STAPH 评分<3 可有效排除 SA，敏感性为 100%，而评分 5 可确认 SA，特异性为 100%。STAPH 评分是一种可靠且高效的工具，可在 BACTEC 系统中快速鉴定血培养中的金黄色葡萄球菌。通过将革兰氏染色观察结果与阳性时间相结合，该方法提高了诊断准确性，降低了主观性，并支持及时的临床决策。
快速准确地鉴定血培养中的金黄色葡萄球菌（SA）对于及时和适当的临床干预至关重要。本研究介绍了“STAPH 评分”，这是一种新的半定量评分系统，它结合了革兰氏染色形态学和阳性时间。通过提供一种可靠且高效的方法来区分 SA 与凝固酶阴性葡萄球菌，STAPH 评分提高了显微镜检查的诊断准确性并降低了主观性。该评分适用于 BACTEC 系统，解决了传统革兰氏染色方法和昂贵的分子技术的局限性。在临床实践中实施 STAPH 评分可以导致更快的诊断、改善患者结局和优化抗菌治疗。该方法在资源有限的环境中特别有价值，在这些环境中可能无法获得先进的诊断工具。
