The Legionellaceae are thin, aerobic, pleomorphic, flagellated, Gram-negative opportunistic intracellular bacteria. They are non-capsulated rod-like bacterium of approximately 2 μm in length and 0.3-0.9 μm in width. Legionella pneumophila has suggested fastidious nutrient requirements, including ferric iron and L-cysteine. The family Legionellaceae consists of a single genus, Legionella. This genus includes the species Legionella pneumophila, the most frequent cause of human legionellosis and it known as Legionnaires’ disease. Hong Kong health officials reported today the death of a 65-year-old man due to Legionnaires’ disease (LD). The patient, with underlying diseases, had presented with fever, cough with sputum and shortness of breath since …show more content…
The most common cause is the freshwater species L. pneumophila which is found in natural aquatic environments. However, artificial water systems like cooling towers, showers, hot water tanks and faucets and heaters which provide environments conducive to the dissemination and growth of Legionella and this sites represent the most likely sources of …show more content…
The two most potent classes of antibiotic are the macrolides (azithromycin), and the quinolones (ciprofloxacin, levofloxacin, moxifloxacin, gemifloxacin, trovofloxacin). Other agents that have been shown to be effective include tetracycline, doxycycline, minocycline, and trimethoprim/sulfamethoxazole. Erythromycin, the former antibiotic of choice, has been replaced by more potent and less toxic antibiotics. There are three major classes of antibiotics that are effective in treating legionellosis. These include the fluoroquinolones such as levofloxacin (Levaquin), and moxifloxacin (Avelox), the macrolides such as erythromycin, azithromyocin (Zithromax), and clarithromycin (Biaxin), and the tetracyclines including doxycycline (Vibramycin). A new class of antibiotics (glycylcyclines) are also effective. The choice of antibiotic is often dependent on the patient's clinical state, tolerance to the medication, and degree of certainty as to the diagnosis. Zithromax and Levaquin are particularly effective because of decreased gastrointestinal irritation, higher potency, better penetration into tissue, and once-daily