Microbiological findings and adequacy of antibiotic treatment in the critically ill patient with drowning-associated pneumonia

Abstract

Dear Editor, One of the main factors contributing to the risk of developing pneumonia after a drowning incident is the aspiration of water or gastric contents. It has been estimated that approximately 90 % of patients aspirate water during a drowning episode and that 10 % die of dry asphyxia caused by laryngospasm [1–4]. Bacteria causing pneumonia in drowning victims are often waterborne or of oropharyngeal origin; fungi have been described as a less common cause of pneumonia in these victims [2]. The main aim of our study was to identify micro-organisms causing drowning-associated pneumonia and compare these to micro-organisms cultured from locally retrieved water samples. With these two goals, we tried to confirm whether the spectrum of our empirical antimicrobial therapy adequately covers the detected microorganisms. From 2001 until 2012 49 drowning victims were admitted to our Intensive Care Unit, of whom 18 developed pneumonia. Drowningassociated pneumonia criteria were: (1) new or persistent chest radiographic evidence of pneumonia; (2) a potentially pathogenic micro-organism cultured from a tracheal aspirate or broncho-alveolar lavage (BAL) fluid; (3) two of the three following criteria: fever (temperature C38.0 C), purulent endotracheal secretions and/or leucocytosis (leucocytes [10.0 9 10 /L) or leucopenia (leucocytes \4.0 9 10/ L). These criteria for pneumonia needed to be present within a time frame of 24 h of a positive culture. Only cases of pneumonia diagnosed within the first week of admission were taken into account. A water sample was retrieved from three different nearby sites associated with drowning incidents: the canals of Amsterdam, a local lake and a wide ditch. Findings were compared with cultures from tracheal aspirate or BAL fluid collected from the patient. Aeromonas spp. and Staphylococcus aureus were the predominantly species of micro-organisms found in patients developing drowning-associated pneumonia (Table 1). Positive sputum and BAL fluid cultures were retrieved within 48 h of admission in 16 of the 18 patients with pneumonia. One patient developed Aspergillus fumigatus pneumonia, and in one case a positive culture yielding Flavobacterium odoratum was found with unclear clinical significance. The most commonly used initial antibiotic regimen consisted of piperacillin ? tobramycin or ceftazidim. Antimicrobial therapy adequately covered the spectrum of cultured microorganisms in 16 of the 18 pneumonia patients (89 %). The majority of the micro-organisms cultured from sputumor BAL cultures from patients with pneumonia were also cultured from the water samples (Table 2). In particular, all three water samples cultures yielded Aeromonas spp. Three different species of Aspergillus were cultured from the different water sites, and no