A cluster of cases of legionellosis have occurred in your neighborhood. People with the illness have cough, fever, shortness of breath, chest pain and sometimes diarrhea. The illness is caused by the bacterium Legionella pneumophila, a facultative intracellular parasite that survives in certain ameba. The organism has an absolute requirement for L-cysteine.
-L. pneumophila is widespread and is found in various water sources, including hot tubs, water cooling towers, swimming pools, grocery store misters, and shower water. Select the False statement regarding the organism, given this information.
A) It survives in the presence of chlorine.
B) It is a mesophile.
C) It is an obligate anaerobe.
D) It can survive in water pipes.
E) It is a mesophile AND it can survive the presence of chlorine.

Question

A cluster of cases of legionellosis have occurred in your neighborhood. People with the illness have cough, fever, shortness of breath, chest pain and sometimes diarrhea. The illness is caused by the bacterium Legionella pneumophila, a facultative intracellular parasite that survives in certain ameba. The organism has an absolute requirement for L-cysteine.
-L. pneumophila is widespread and is found in various water sources, including hot tubs, water cooling towers, swimming pools, grocery store misters, and shower water. Select the False statement  regarding the organism, given this information.
A) It survives in the presence of chlorine.
B) It is a mesophile.
C) It is an obligate anaerobe.
D) It can survive in water pipes.
E) It is a mesophile AND it can survive the presence of chlorine.

Quizplus · Accepted Answer

L. pneumophila is not an obligate anaerobe, as it can grow in the presence of oxygen. It is a facultative intracellular parasite, meaning it can survive and multiply within host cells, but can also grow outside of them. It is also a mesophile, meaning it grows best at moderate temperatures between 25-45°C. However, it can survive in colder temperatures as well. L. pneumophila is known to survive in water pipes, and has been found to grow in biofilms that can form in plumbing systems. While chlorine is commonly used as a disinfectant for water, L. pneumophila has been shown to survive in the presence of low levels of chlorine, especially in biofilm environments. Therefore, statement E is also false; L. pneumophila is a mesophile but it cannot always survive in the presence of chlorine.

A Cluster of Cases of Legionellosis Have Occurred in Your