Ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin and trovafloxacin have all been shown to inhibit the intracellular growth of L. pneumophila in either guinea pig alveolar macrophages 17,18,19 or HL-60 cells.

In one comparative study of in-vitro, extracellular susceptibility sparfloxacin and trovofloxacin were the most active, ciprofloxacin, levofloxacin, ofloxacin and lomefloxacin were slightly less active, and pefloxacin was the least active. 15 However, all the quinolones tested can be said to have good activity and low MICs (Table). Quinolones readily enter the intracellular compartment.

Within HL-60 cells azithromycin achieves the greatest inhibition of growth of L. pneumophila

Amongst the macrolides most experience has been gained with erythromycin. However, by in-vitro extracellular, testing it is less active than clarithromycin, azithromycin and roxithromycin, although more active than dirithromycin and josamycin (Table). In some comparative studies clarithromycin has been more active than azithromycin

by coiling phagocytosis, once phagocytized, the Legionella bacteria reside within a unique phagosome and do not fuse with lysosomes or become highly acidic

Legionella pneumophila antigen—this is the preferred initial test for Legionnaires disease. It detects one of the bacterium's proteins. It is performed on urine and occasionally on another body fluid. It is a rapid way to detect an infection, but it will only detect Legionella pneumophila serogroup 1. Since this is the most common cause of Legionnaires disease in the U.S., it will detect most infections in adults. Legionella culture—this type of culture may be performed along with a routine sputum culture because special nutrient media is required to encourage the growth of Legionella and discourage the growth of other bacteria. This test is considered the "gold standard" for diagnosing an infection caused by Legionella bacteria. A positive culture may be determined in about 48 to 72 hours. Negative cultures are held for at least 7 days before a final result is reported. A culture will identify multiple Legionella species and is used both to confirm that a person has a legionella infection and to help identify the source of an outbreak. Direct fluorescent antibody (DFA) staining for Legionella species—this is a rapid test that can be performed on respiratory samples and tissue and requires only 2 to 4 hours for results. Legionella species by polymerase chain reaction (PCR)—this test detects bacterial genetic material, primarily in respiratory secretions but sometimes in other body fluids. It can detect several species of Legionella but is not widely used.

• Temperature above 68° F • Iron • L-Cysteine • Biofilm (particularly protozoans)

found naturally in freshwater environments, like lakes and streams

Large plumbing systems

In general, people do not spread Legionnaires’ disease and Pontiac fever to other people.

People at Increased Risk Most healthy people exposed to Legionella do not get sick. People at increased risk of getting sick are: People 50 years or older Current or former smokers

Cooling towers(https://www.cdc.gov/healthywater/other/industrial/cooling_towers.html) (air-conditioning units for large buildings)

People 50 years or older Current or former smokers

In general, people do not spread Legionnaires’ disease and Pontiac fever to other people.

L. pneumophila is a significant human pathogen that lives in amoebae in the environment but may opportunistically infect the alveolar macrophage. To maintain its intracellular lifestyle, Legionella extracts essential iron from the cell, blocks inflammatory responses and manipulates trafficking to avoid fusion with the lysosome.

The Mip protein exhibits activity of a peptidyl prolyl cis trans isomerase (PPIase), an enzyme which is able to bind the immunosuppressant FK506 and is involved in protein folding. The recently cloned major outer membrane protein (MOMP) could play a role in the uptake of legionellae by macrophages.

Legionella bacilli reside in surface and drinking water and are usually transmitted to humans in aerosols

Many antibiotics are highly effective against Legionella bacteria. 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.

Symptoms usually begin 2 to 10 days after being exposed to the bacteria, but it can take longer so people should watch for symptoms for about 2 weeks after exposure.

Legionnaires’ disease can also be associated with other symptoms such as diarrhea, nausea, and confusion

Cough Shortness of breath Fever Muscle aches Headaches

Abnormal sounds called crackles may be heard when listening to the chest with a stethoscope.

Chest painCough that does not produce much sputum or mucus (dry cough)Coughing up bloodDiarrhea, nausea, vomiting, and abdominal painFever, shaking chillsGeneral discomfort, uneasiness, or ill feeling (malaise)HeadacheJoint painLoss of energyMuscle aches and stiffnessProblems with balanceShortness of breath

Risk factors include:Alcohol abuseCigarette smoking

Culture Clinical and environmental isolates can be compared Detects all species and serogroups Technically difficult Slow (>5 days to grow) Sensitivity highly dependent on technical skill May be affected by antibiotic treatment Requires BCYE agar, which some laboratories may not have readily available

The most commonly used laboratory test for diagnosis is the urinary antigen test, which detects a part of the Legionella bacterium in urine. If the patient has pneumonia and the test is positive, then the patient is considered to have Legionnaires' disease.

Isolation of Legionella from lower respiratory secretions, lung tissue, pleural fluid, or a normally sterile site is confirmatory and an important method for diagnosis.

Patients who have failed outpatient antibiotic therapy for community-acquired pneumonia Patients with severe pneumonia, in particular those requiring intensive care Immunocompromised patients with pneumonia Patients with pneumonia in the setting of a legionellosis outbreak Patients with a travel history (patients that have traveled away from their home within two weeks before the onset of illness)

Urine test Laboratory test that involves taking a sample of sputum (phlegm) or washing from the lung