title: Microbiological diagnosis and molecular typing of Legionella strains during an outbreak of legionellosis in Southern Germany.
abstract: An explosive outbreak of Legionnaires' disease with 64 reported cases occurred in Ulm/Neu-Ulm in the South of Germany in December 2009/January 2010 caused by Legionella (L.) pneumophila serogroup 1, monoclonal (mAb) subtype Knoxville, sequence type (ST) 62. Here we present the clinical microbiological results from 51 patients who were diagnosed at the University hospital of Ulm, the results of the environmental investigations and of molecular typing of patients and environmental strains. All 50 patients from whom urine specimens were available were positive for L. pneumophila antigen when an enzyme-linked immunosorbent assay (EIA) was used following concentration of those urine samples that tested initially negative. The sensitivity of the BinaxNow rapid immunographic assay (ICA), after 15 min reading and after 60 min reading were 70% and 84%, respectively. Direct typing confirmed the monoclonal subtype Knoxville in 5 out of 8 concentrated urine samples. Real time PCR testing of respiratory tract specimens for L. pneumophila was positive in 15 out of 25 (60%) patients. Direct nested sequence based typing (nSBT) in some of these samples allowed partial confirmation of ST62. L. pneumophila serogroup 1, monoclonal subtype Knoxville ST62, defined as the epidemic strain was isolated from 8 out of 31 outbreak patients (26%) and from one cooling tower confirming it as the most likely source of the outbreak. While rapid detection of Legionella antigenuria was crucial for the recognition and management of the outbreak, culture and molecular typing of the strains from patients and environmental specimens was the clue for the rapid identification of the source of infection.
authors: Institute of Medical Microbiology and Hygiene, Ulm University Hospital, Ulm, Germany.
authors: Andreas
authors: A
authors: Essig
authors: Institute of Medical Microbiology and Hygiene, Ulm University Hospital, Ulm, Germany.
authors: Heike
authors: H
authors: von Baum
authors: Public Health Authority Ulm, Ulm, Germany.
authors: Theodor
authors: T
authors: Gonser
authors: Department of Internal Medicine III, Section of Infectious Diseases, Ulm University Hospital, Ulm, Germany.
authors: Georg
authors: G
authors: Haerter
authors: Institute of Medical Microbiology and Hygiene, German Consiliary Laboratory for Legionella, Dresden University of Technology, Dresden, Germany. Electronic address: Christian.Lueck@Uniklinikum-Dresden.de.
authors: Christian
authors: C
authors: Lück
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000652:urine; D004269:DNA, Bacterial / Q000032:analysis; D004196:Disease Outbreaks; D004783:Environmental Microbiology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007875:Legionella / Q000145:classification* / Q000235:genetics / Q000276:immunology; D007876:Legionellosis / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D012137:Respiratory System / Q000382:microbiology; D012703:Serotyping
chemical_list: D000942:Antigens, Bacterial; D004269:DNA, Bacterial
keywords: Cooling tower; Legionella pneumophila; Legionnaire's disease; Molecular typing; Outbreak; Pneumonia