Harrell Kevin N, Koestner Tyler, Lloyd Jacob, Carter Breanna L, Hunt Darren, Dart Benjamin, Maxwell Robert
Department of Surgery, University of Tennessee College of Medicine Chattanooga, Chattanooga, Tennessee.
Department of Surgery, University of Tennessee College of Medicine Chattanooga, Chattanooga, Tennessee; Department of Surgery, University of Kentucky School of Medicine, Lexington, Kentucky.
J Surg Res. 2023 May;285:45-50. doi: 10.1016/j.jss.2022.12.014. Epub 2023 Jan 12.
Methicillin-resistant staphylococcus aureus (MRSA) nasal colonization is a predictor of MRSA pneumonia in intensive care unit (ICU) patients. Negative nasal swabs have shown up to a 97% negative predictive value for MRSA pneumonia in nontrauma populations, though little investigation has been pursued in trauma patients.
All trauma patients admitted to the ICU from April 2018 to February 2019 were screened for MRSA colonization by nasal swab. Patients with suspicion for pneumonia underwent bronchoalveolar lavage or quantitative sputum culture and were started on empiric antibiotic therapy based on the swab result. Swab-positive patients were started on empiric MRSA coverage and swab-negative patients were not.
MRSA nasal swab screening was performed in 601 trauma ICU patients. Ninety-six patients subsequently underwent pneumonia workup and were started on an empiric antibiotic regimen based on nasal swab results. Seventeen (17.7%) patients were MRSA nasal swab positive on screening, and 22 (22.9%) patients subsequently had significant growth of MRSA on quantitative respiratory culture. The sensitivity of nasal swab was 50.0% and the specificity was 91.9%. Eleven patients had a negative MRSA nasal swab but a positive MRSA pneumonia (11.5%). Patients with inadequate antibiotic coverage had statistically longer hospital length of stay, ICU length of stay, ventilator days, and rates of unplanned intubation compared to patients with adequate antibiotic coverage.
Nasal swab screening was not sensitive enough in a trauma population with a high endemic incidence of MRSA colonization to warrant withholding empiric antibiotic MRSA coverage in patients with suspected pneumonia.
耐甲氧西林金黄色葡萄球菌（MRSA）鼻腔定植是重症监护病房（ICU）患者发生MRSA肺炎的一个预测指标。在非创伤人群中，鼻腔拭子检测结果为阴性对MRSA肺炎的阴性预测值高达97%，不过对创伤患者的相关研究较少。
对2018年4月至2019年2月入住ICU的所有创伤患者进行鼻腔拭子检测，以筛查MRSA定植情况。疑似肺炎的患者接受支气管肺泡灌洗或定量痰培养，并根据拭子检测结果开始经验性抗生素治疗。拭子检测结果为阳性的患者开始接受经验性MRSA覆盖治疗，拭子检测结果为阴性的患者则不进行该治疗。
对601例创伤ICU患者进行了MRSA鼻腔拭子筛查。随后有96例患者接受了肺炎检查，并根据鼻腔拭子结果开始经验性抗生素治疗方案。17例（17.7%）患者在筛查时鼻腔拭子MRSA检测呈阳性，22例（22.9%）患者随后在定量呼吸道培养中发现MRSA大量生长。鼻腔拭子的敏感性为50.0%，特异性为91.9%。11例患者鼻腔拭子MRSA检测为阴性，但MRSA肺炎检测为阳性（11.5%）。与抗生素覆盖充分的患者相比，抗生素覆盖不充分的患者在统计学上住院时间更长、ICU住院时间更长、机械通气天数更多且非计划插管率更高。
在MRSA定植流行率高的创伤人群中，鼻腔拭子筛查的敏感性不足以保证对疑似肺炎患者不进行经验性MRSA抗生素覆盖治疗。
