Hospital-acquired pneumonia in critically ill children: Incidence, risk factors, outcome and diagnosis with insight on the novel diagnostic technique of multiplex polymerase chain reaction

Abstract

Hospital-acquired pneumonia (HAP) is the most frequent hospital-acquired infection in critically ill patients. National Nosocomial Infections Surveillance (NNIS) system reported that HAPaccounts for as much as 31% of all nosocomial infections acquired in medical intensive care units (ICU). The increasing incidence of infections caused by antibiotic-resistant pathogens contributes to a high mortality rate, longer ICU stay and higher costs. In this study, we aimed to identify the incidence of HAP, the associated risk factors, and its effect on outcome. We evaluated as well the usefulness of multiplex polymerase chain reaction (m-PCR) as a novel tool for emergency diagnosis of HAP. We examined all consecutive admissions to Pediatric ICU from February 2010 to August 2010. Patients were diagnosed to have HAP when their Clinical Pulmonary Infection Score (CPIS) index was more than 6. Blood and endotracheal aspirate (ETA) were tested for bacterial pathogens by microbiological cultures and multiplex PCR simultaneously for all enrolled patients. Twenty-five patients out of 90 admissions (27.7%) developed HAP during the observation period, with incidence rate of 13 per 1000 patient-days and overall mortality of 56%. Gastro-esophageal reflux disease (GERD), mechanical ventilation (MV), endotracheal re-intubation and sedation were the main recorded risk factors for HAP. ETA had better diagnostic yield than blood specimens for the diagnosis of HAP. Multiplex-PCR showed better sensitivity and positive predictive value than bacterial culture for etiological diagnosis of HAP. Acinetobacter and Klebsiella pneumoniae were the most common identified pathogens. In conclusion, hospital-acquired pneumonia adversely affects patients outcome in our setting, for which we should manipulate the identified modifiable risk factors. Moreover, m-PCR permits simultaneous detection of several bacterial pathogens in a single reaction which can optimize the emergency diagnosis ofHAPand can improve etiology-directed clinical management of bacterial pneumonia.

Keywords: m-PCR; Hospital-acquired pneumonia; Bacterial diagnosis; Risk factors; Outcome