Transmission of Extended-Spectrum β -Lactamase Klebsiella oxytoca via the Breathing Circuit of a Transport Ventilator: Root Cause Analysis and Infection Control Recommendations

Abstract

The second patient had been treated for subarachnoid haemorrhage for 8 days when the index patient was admitted to the intensive care unit (ICU; Germany). On day 14 of the second patient's ICU stay, Gram negative rods were cultured from a surveillance nasal swab specimen for the first time and were subsequently identified as Klebsiella oxytoca. The antibiotic resistance profile of this strain was identical to that of the strain isolated from the index patient. This triggered a red flag alert for a possible transmission and a root cause analysis. The epidemiological time course was analysed. Both patients had undergone bronchoscopy but on 2 different days and with different bronchoscopes and different operators. The analysis of the reprocessing of the bronchoscopes and testing of the disinfection machine did not reveal any problems. Observation of nursing practice revealed good hand hygiene compliance. When it became obvious that both patients had been transported to the computed tomography scanner on the same day (before contact precautions were initiated) with the same transport ventilator, the focus of the investigation shifted to the transport ventilator. Swab samples were obtained from different parts of the transport ventilator (Oxylog 3000), and samples obtained at the distal end of the breathing circuit close to the patient grew K. oxytoca. Genetic testing (with random amplified polymorphic DNA analysis) confirmed that the strain isolated from the transport ventilator was identical to the strains isolated from both patients.