Clinical, laboratorial and radiographic predictors of Bordetella pertussis infection

OBJECTIVE: To identify clinical, laboratorial and radiographic predictors for Bordetella pertussis infection.METHODS: This was a retrospective study, which analyzed medical records of all patients submitted to a molecular dignosis (qPCR) for B. pertussis from September 2011 to January 2013. Clinical and laboratorial data were reviewed, including information about age, sex, signs/symptoms, length of hospitalization, blood cell counts, imaging findings, coinfection with other respiratory pathogens and clinical outcome.RESULTS: 222 cases were revised. Of these, 72.5% had proven pertussis, and 60.9% were under 1 year old. In patients aging up to six months, independent predictors for B. pertussisinfection were (OR 8.0, CI 95% 1.8-36.3; p=0.007) and lymphocyte count >104/µL (OR 10.0, CI 95% 1.8-54.5; p=0.008). No independent predictors of B. pertussisinfection could be determined for patients older than six months. Co-infection was found in 21.4% of patients, of which 72.7% were up to six months of age. Adenovirus was the most common agent (40.9%). In these patients, we were not able to identify any clinical features to detect patients presenting with a respiratory co-infection, even though longer hospital stay was observed in patients with co-infections (12 vs. 6 days; p=0.009).CONCLUSIONS: Cyanosis and lymphocytosis are independent predictors for pertussis in children up to 6 months old.研究目的：明确百日咳博德特菌（Bordetella pertussis）感染的临床、实验室及影像学预测因子。 研究方法：本研究为回顾性研究，分析了2011年9月至2013年1月期间所有接受百日咳博德特菌分子诊断（qPCR）的患者的病历资料。回顾性收集并分析患者的临床及实验室数据，涵盖年龄、性别、体征与症状、住院时长、血细胞计数、影像学表现、合并其他呼吸道病原体感染情况以及临床转归。 研究结果：共纳入222例病例进行回顾分析。其中72.5%的病例确诊为百日咳，60.9%的患者年龄小于1岁。在≤6月龄的患者中，百日咳博德特菌感染的独立预测因子为发绀（比值比OR 8.0，95%置信区间CI 1.8~36.3；P=0.007）以及淋巴细胞计数＞104/µL（OR 10.0，95%置信区间CI 1.8~54.5；P=0.008）。对于＞6月龄的患者，未发现百日咳博德特菌感染的独立预测因子。21.4%的患者存在合并感染，其中72.7%为≤6月龄患儿。腺病毒为最常见的合并感染病原体（占比40.9%）。尽管合并感染患者的住院时长更长（12天 vs. 6天；P=0.009），但本研究未能通过临床特征识别出合并呼吸道感染的患者。 研究结论：对于≤6月龄的儿童，发绀与淋巴细胞增多症是百日咳的独立预测因子。