A recent New York Times article, Genome Detectives Solve a Hospital’s Deadly Outbreak, printed on August 23, 2012, describes a Maryland hospital’s efforts to deal with an unusual nosocomial (hospital related) outbreak that led to 18 infections and six deaths. In June, a woman entered the hospital with Klebsiella pneumoniae, a rare and deadly bacterial illness and was treated in strict isolation. She recovered and was released from the hospital a month later, but in August the bacterium was found in another patient. Soon 17 more patients had become ill. The hospital used genetic sequencing of the bacteria and discovered that all illnesses were derived from the first case. They also learned that the bacteria had survived in a respirator (despite disinfection efforts) and in sink drains within the hospital. The bacteria had continued to grow and spread to other patients.
Legionnaires’ disease is a noncommunicable illness in which failure to fully isolate an ill patient is not a concern. However, it is a nosocomial illness and some aspects of the investigation into the deadly Klebsiella pneumonaie outbreak seem to apply. When biological samples (samples of bacteria from sick patients) are taken during a Legionnaires’ disease investigation, clinical isolates may be obtained. These isolates can be matched to environmental samples from the suspected source of the bacteria upon investigation by health departments or independent testing agencies. Similar to in the Klebsiella pneumonia story, epidemiologists can ascertain where a given patient became sick using this methodology. However, a major problem is that clinical isolates are oftentimes not available from patients due to the tendency to underdiagnose Legionnaires’ disease, patients traveling away from the region where the outbreak occurred (especially if it is a hotel-related outbreak), and the simple elapse of time since the acquisition of the bacteria.
Genetic sequencing helped to uncover the source of the Klebsiella pneumonia outbreak in Maryland. While 18 people became sick and six people died, the process helped to uncover the source of the bacteria and prevent future problems. The idea of matching isolates of bacteria from environmental samples with those in the patient population is used in Legionnaires’ disease investigations as well. Beyond the science, this fact remains: hospitals should be places to get better, not places to acquire nosocomial illnesses such as Klebsiella pneumonia and Leigonnaires’ disease.
Jules Zacher is an experienced attorney who has worked on Legionnaires’ disease cases throughout the country. He has litigated several cases involving outbreaks at hospitals.