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399 Bacteriology of aspiration pneumonia due to delayed triggering of the swallowing reﬂex in elderly patients
Madam, Aspiration is important as a frequent mechanism for hospital-acquired pneumonia.1 However, the aetiological agents of aspiration pneumonia have not been well characterised because of thedifﬁculty in diagnosis. Recently, aspiration pneumonia was deﬁned by the Japanese Study Group on Aspiration Pulmonary Disease as pneumonia in a patient with predisposition to aspiration due to dysphagia or swallowing disorders.2 Here, the swallowing dysfunction was assessed by evaluating the latent time of the swallowing reﬂex, induced by an injection of 1 mL solution into the pharynx.3 In this study,the aetiology of aspiration pneumonia diagnosed by assessment of swallowing reﬂex was investigated. Patients were prospectively and consecutively recruited from those referred and admitted to the Geriatric Unit, in Tohoku University Hospital for treatment of pneumonia from April 2003 to May 2008. Pneumonia was diagnosed by the presence of pulmonary inﬁltration on chest radiograph and computedtomography and according to systemic inﬂammation determined according to white blood cell (WBC) count and C-reactive protein (CRP). The criteria for pneumonia were established according to the pneumonia guidelines of the Japan Respiratory Society.4 Patients with severe immunosuppression (solid organ transplantation, steroid therapy of !20 mg/day for >2 weeks, known human immunodeﬁciency virus, oracquired immune deﬁciency syndrome-deﬁning criteria) or who had received antibiotics within 6 weeks were excluded. In our unit, all elderly patients (>75 years old) with pneumonia had fasted at time of admission. When they had recovered after treatment such as intravenous antibiotics, consideration was given to letting them restart eating. Their swallowing reﬂex was estimated before making the decisionto start eating. The swallowing reﬂex was induced by a bolus injection of 1 mL distilled water into the pharynx through a nasal catheter (8F). The subjects were unaware of the actual injection. Swallowing was identiﬁed by submental electromyographic (EMG) activity and visual observation of characteristic laryngeal movement. EMG activity was recorded from surface electrodes on the chin. Theswallowing reﬂex was evaluated by the latency of response, timed from the injection to the onset of swallowing.3 If the latency of
M. Almuzaraa,* M. Matteob R. Cittadinic E. Bertonac R. Armitanob M. Catalanob M. del Castilloc C. Vaya,c a ´ Laboratorio de Bacteriologıa, Instituto de ´ ´ ´ Fisiopatologıa y Bioquımica Clınica, Facultad de ´ Farmacia y Bioquımica, Universidad...