ABSTRACT
During a nine-day period, five patients in a 14-bed intensive care unit (ICU) were shown to have seroconverted with a four-fold or greater rise in serum antibody titre to Legionella longbeachae serogroup 1. A further two patients were observed to have high titres consistent with previous exposure but earlier serum samples were not available for comparison. No patients had antibody responses to Legionella pneumophila serogroups 1 and 2. L. longbeachae was not cultured from respiratory secretions from patients or from the environment within the unit. Legionella anisa was recovered from one cooling tower on the ninth floor of the tower block. The ICU is located on the first floor of the same tower and receives external air from two vents, one on the eastern and the other on the western aspect. All patients with serological evidence of L. longbeachae infection were concomitantly infected with multiresistant Staphylococcus aureus, and were located in bays on the eastern side of the unit. A large pigeon nest was discovered within 1-2 m of the eastern vent. Following removal of the birds' nest, no further cases were seen on routine screening of all patients within the unit over the next eight weeks. Alternatively, seroconversion may have been related to demolition of the adjacent nine-storey nurses home. This was begun one month before the first case was diagnosed and was completed four months later. The periodic northerly winds could have carried legionellae from the demolition site directly over the block housing the ICU and may have concentrated them near the eastern air vent. All patients had pneumonia, which was probably multifactorial in origin. There is some uncertainty whether the serological responses seen were an epiphenomenon or were truly indicative of infection with L. longbeachae.
Subject(s)
Air Conditioning , Cross Infection/etiology , Disease Outbreaks/statistics & numerical data , Intensive Care Units , Legionellosis/etiology , Pneumonia, Bacterial/etiology , Water Microbiology , Aged , Animals , Antibodies, Bacterial/blood , Columbidae/microbiology , Cross Infection/diagnosis , Cross Infection/epidemiology , Cross Infection/prevention & control , Disease Outbreaks/prevention & control , Environmental Monitoring/methods , Epidemiological Monitoring , Female , Hospital Design and Construction , Humans , Infection Control/methods , Interior Design and Furnishings , Legionellosis/diagnosis , Legionellosis/epidemiology , Legionellosis/prevention & control , Male , Methicillin Resistance , Middle Aged , Pneumonia, Bacterial/diagnosis , Pneumonia, Bacterial/epidemiology , Pneumonia, Bacterial/prevention & control , Risk Factors , South Australia/epidemiology , Staphylococcal Infections/etiology , Staphylococcus aureusABSTRACT
Ten commercial transport swabs were evaluated for their ability to preserve bacteria for 24 and 48 hours. Microorganisms included ATCC strains of Gram-positive and Gram-negative aerobes and anaerobes. There was a wide variation in performance. Swabs using Amies plus charcoal medium or Stuart's medium had better recovery rates than those using Amies medium alone. The nature of the tips of the swabs had little influence. Performance was not correlated with cost of the swabs. These data will assist institutions to make cost-effective decisions when purchasing bacteriological transport systems.
