Pathogenicity of the family Legionellaceae
The Legionellae are Gram-negative bacteria able to survive and replicate in a wide range of protozoan hosts in natural environments, but they also occur in man-made aquatic systems, which are the major source of infection. After transmission to humans via aerosols, Legionella spp. can cause pneumonia (Legionnaires' disease) or influenza-like respiratory infections (Pontiac fever). In children, Legionnaires' disease is uncommon and is mainly diagnosed in children with immunosuppression. The clinical picture of Legionella pneumonia does not allow differentiation from pneumonia caused by others pathogens. The key to diagnosis is performing appropriate microbiological testing. The clinical presentation and the natural course of Legionnaires' disease in children are not clear due to an insufficient number of samples, but morbidity and mortality caused by this infection are extremely high. The mortality rate for legionellosis depends on the promptness of an appropriate antibiotic therapy. Fluoroquinolones are the most efficacious drugs against Legionella. A combination of these drugs with macrolides seems to be promising in the treatment of immunosuppressed patients and individuals with severe legionellosis. Although all Legionella species are considered potentially pathogenic for humans, Legionella pneumophila is the etiological agent responsible for most reported cases of community-acquired and nosocomial legionellosis.
Available from: Thomas Egli
- "Since their favoured growth temperatures lie in the range of 20–45°C, man‐made installation systems, such as showers, air conditioners, and cooling towers are of major concern (Fields et al., 2002). Legionella pneumophila (Lp) is the causative agent of 50–90% of all infections (Breiman and Butler, 1998; Yu et al., 2002; Yáñez et al., 2005; Pravinkumar et al., 2010), though most Ls are potentially human pathogens (Alli et al., 2003; Palusińska‐Szysz and Cendrowska‐Pinkosz, 2009). In 2011 the incidence recorded by the Swiss mandatory surveillance system was 3.2 cases/100 000 inhabitants (BAG, 2012). "
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ABSTRACT: We developed a rapid detection method for Legionella pneumophila (Lp) by filtration, immunomagnetic separation, double fluorescent staining, and flow cytometry (IMS-FCM method). The method requires 120 min and can discriminate 'viable' and 'membrane-damaged' cells. The recovery is over 85% of spiked Lp SG 1 cells in 1 l of tap water and detection limits are around 50 and 15 cells per litre for total and viable Lp, respectively. The method was compared using water samples from house installations in a blind study with three environmental laboratories performing the ISO 11731 plating method. In 53% of the water samples from different taps and showers significantly higher concentrations of Lp were detected by flow cytometry. No correlation to the plate culture method was found. Since also 'viable but not culturable' (VNBC) cells are detected by our method, this result was expected. The IMS-FCM method is limited by the specificity of the used antibodies; in the presented case they target Lp serogroups 1-12. This and the fact that no Lp-containing amoebae are detected may explain why in 21% of all samples higher counts were observed using the plate culture method. Though the IMS-FCM method is not yet fit to completely displace the established plating method (ISO 11731) for routine Lp monitoring, it has major advantages to plating and can quickly provide important insights into the ecology of this pathogen in water distribution systems.
Available from: Andi Yasmon
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ABSTRACT: Abstrak Tujuan: Metode kultur memiliki sensitivitas yang rendah dan memerlukan waktu yang lama untuk mendeteksi bakteri Legionella. Oleh karena itu, dalam penelitian ini dikembangkan uji PCR duplex (dPCR) untuk deteksi Legionella sp. dan L. peneumophila secara simultan pada sampel air tower. Metode kultur digunakan sebagai baku emas. Metode: Dilakukan optimasi metode dPCR untuk mendapatkan teknik uji yang memiliki sensitivitas dan spesifi sitas tinggi. Metode kemudian diuji pada 9 sampel air tower yang diperoleh dari 9 gedung di Jakarta. Untuk metode kultur, bakteri ditumbuhkan pada media selektif 'growth factor supplemented-buffered charcoal yeast extract' (BCYE). Hasil: Dari 9 sampel yang diuji dengan dPCR, 6 menunjukkan positif Legionella sp., 1 positif L. pneumophila, dan 2 menunjukkan hasil uji negatif. Untuk sampel yang sama, metode kultur menunjukkan hasil uji negatif. Kesimpulan: Uji dPCR adalah uji yang sangat sensitif dibandingkan dengan metode kultur, dan uji dPCR ini dapat digunakan untuk pemeriksaan rutin Legionella sp. dan L. pneumophila pada sampel air dari 'tower'. Abstract Aim: Since culture method is time-consuming and has low sensitivity, we developed a duplex PCR (dPCR) assay for the detection of Legionella sp. and L. pneumophila in cooling tower samples. We used culture method as a gold standard. Methods: Optimization of dPCR method was performed to obtain an assay with high sensitivity and specifi city. The optimized method was used to detect Legionella sp. dan L. pneumophila in 9 samples obtained from 9 buildings in Jakarta. For culture method, the bacteria were grown or isolated on selective growth factor supplemented-buffered charcoal yeast extract (BCYE) media. Results: Of 9 samples tested by dPCR assay, 6 were positive for Legionella species,1 was positive for L. pneumophila, and 2 showed negative results. For the same samples, no Legionella sp. was detected by the culture method.
Available from: Dorota Rogowska-Szadkowska
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ABSTRACT: In order to assess the nurses' knowledge concerning the risk of hepatitis B and C viruses or human immunodeficiency virus infection while performing their professional duties, an anonymous questionnaire developed by the authors was distributed in 2008. Surprisingly 64% respondents occasionally recapping needles after injections, although they know the procedures which are obligatory at the ward. The first step in preventing percutaneous injuries should focus on efforts to eliminate the practice of recapping needles, though education and convenient placement of puncture-resistant containers for the disposal of used sharps.
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