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.
Qasem
J A
JA
Department of Applied Medical Sciences, College of Health Sciences, The Public Authority for Applied Education and Training, Kuwait University, Kuwait. qasemj@paaet.edu.kw
Mustafa
A S
AS
Khan
Z U
ZU
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