Legionella in clinical specimens and hospital water supply facilities: molecular detection and genotyping of the isolates.
OBJECTIVE
To evaluate genus- and species-specific polymerase chain reactions (PCRs) for the detection of the genus Legionella and the species Legionella pneumophila in clinical specimens and hospital water supplies, and to establish a simple and reproducible random amplification of polymorphic DNA (RAPD)-PCR technique for genotyping of Legionella.


METHODS
A total of 70 respiratory tract specimens(bronchoalveolar lavage: n = 46; endotracheal secretions: n = 9; sputum: n = 15) from patients with atypical pneumonia, and 283 environmental samples (water: 20; swabs: 263) collected from water storage and supply facilities of the Mubarak Al-Kabeer Hospital, Kuwait, were tested by culture and genus-specific PCR for the detection of Legionella. The L. pneumophila isolates were subsequently typed by serology and RAPD-PCR using serotype-specific sera and arbitrary primers, respectively.


RESULTS
Of the 70 clinical samples, culture yielded 2 (2.9%) whereas genus-specific PCR detected Legionella in 20 (28.6%) samples. The 2 culture-positive specimens were also positive for L.-pneumophila-specific PCR. Testing of swab and water samples by culture and genus-specific PCR yielded 61 (21.6%) and 67 (23.7%) positive samples, respectively. All of the 61 culture-positive samples were also positive by genus-specific PCR and 45 of them were positive for L.-pneumophila-specific PCR. Serological typing of 43 L. pneumophila isolates showed that 8 of these belonged to serotype 1 and 35 to serotype 3; however, RAPD-PCR analyses demonstrated polymorphisms among the isolates of both serotypes.


CONCLUSIONS
A higher association between PCR and culture was observed for the environmental samples than for the clinical samples. The application of genus- and species-specific PCRs and RAPD is useful in the detection and typing of Legionella in clinical and environmental samples.
Department of Applied Medical Sciences, College of Health Sciences, The Public Authority for Applied Education and Training, Kuwait University, Kuwait. qasemj@paaet.edu.kw
J A
JA
Qasem
A S
AS
Mustafa
Z U
ZU
Khan
D046508:Culture Techniques; D004865:Equipment and Supplies, Hospital / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D007875:Legionella / Q000235:genetics* / Q000302:isolation & purification*; D007876:Legionellosis / Q000175:diagnosis / Q000382:microbiology*; D019105:Random Amplified Polymorphic DNA Technique / Q000379:methods*; D014871:Water Microbiology; D014881:Water Supply