RESUMO
A Flavobacterium meningosepticum outbreak, involving 12 infected and 47 colonized intensive care patients during the months of February through July 1990, was investigated. F. meningosepticum was isolated from tap water and ice, but these environmental strains eventually proved to be distinct from those colonizing patients. A review of newly colonized patients' charts revealed that a common factor among the patients was daily changes of ventilator tubing pasteurized in the hospital's central sterile department. More than 90% of patients in the outbreak had been on ventilators that used the pasteurized tubing. An investigation of the pasteurization process found that two pasteurizer tanks had been operating at suboptimal temperatures (< 62 degrees C). Cultures of water from the tanks and droplets of water found in the pasteurized tubing grew species of Acinetobacter, Moraxella, and Pseudomonas but did not grow F. meningosepticum. After deficiencies in the pasteurization process were corrected, the outbreak terminated. Despite the failure to culture F. meningosepticum, an analysis of gram-negative bacillary isolates showed that the deficiency in the pasteurization process was a major contributor to colonization of ventilated patients by bacteria ubiquitous in tap water.
Assuntos
Infecção Hospitalar/epidemiologia , Surtos de Doenças , Flavobacterium/isolamento & purificação , Infecções por Bactérias Gram-Negativas/epidemiologia , Unidades de Terapia Intensiva , Almoxarifado Central Hospitalar/normas , Infecção Hospitalar/microbiologia , Contaminação de Equipamentos , Infecções por Bactérias Gram-Negativas/microbiologia , Hospitais com mais de 500 Leitos , Hospitais Universitários , Humanos , Pennsylvania/epidemiologia , Respiração Artificial/instrumentação , Estudos Retrospectivos , Esterilização , Microbiologia da Água , Abastecimento de ÁguaRESUMO
Bacterial pneumonia is the most common cause of early morbidity and mortality (less than 2 weeks) after heart-lung transplantation. The majority (76%) of cultures taken from human donor tracheas at the time of explant grew bacteria. The abnormal immune response of the lung allograft and the common finding of bacterial contamination of lung donors led us to hypothesize that clinically silent bacterial contamination of the donor lung progresses to pneumonia in the recipient and that antibiotic treatment of donors will prevent the development of pneumonia in the recipient. Inocula of Streptococcus pneumoniae were instilled into the left middle lobe of normal and donor dogs to identify the number of bacteria that would result in pneumonia in a normal animal and the amount that, when given to a donor, would result in pneumonia in the recipient. Initial studies established that inocula of 10(4) colony-forming units of S. pneumoniae did not result in pneumonia in normal or immunosuppressed animals. When 10(4) colony-forming units or as few as 10(2) were instilled into the left middle lobe of donors 24 hours before explantation and use of the lung for transplantation, severe acute bronchopneumonia developed in all 18 recipients. Treatment of donors with aerosol and intravenous antibiotics, but not with either alone, prevented pneumonia in the recipients. We conclude that bacterial contamination of the donor lung leads to pneumonia in recipients. Intravenous and aerosol antibiotic treatment of donors with bacterial contamination prevents pneumonia in canine lung recipients. Treatment of human donors with this antibiotic regimen may decrease the prevalence of early bacterial pneumonia.