Researchers from the University of Colorado in the United States sampled and tested shower heads in homes and public places in five states, including New York, Illinois, Colorado, Tennessee and North Dakota. After testing nearly 50 shower heads selected from 9 cities, they found that 30% of the shower heads contained a large number of Mycobacterium avium, which can cause lung diseases. This is an atypical mycobacterium tuberculosis. The researchers sampled and analyzed the water released by the shower head and the water flowing out of the water pipe after removing the shower head. At the same time, they also picked out the internal dirt of the removed shower head for testing. By detecting the deoxyribonucleic acid (DNA) of these samples, scientists found that compared with the hot water flowing from the shower head, Mycobacterium avium accumulated in the shower head, and the number of Mycobacterium avium in the shower head was more than 100 times higher than that in tap water. The water samples in this study, except 4 from rural households, are from urban water supply systems. Due to the use of private pipes for water supply, no Mycobacterium avium was found in the water flowing out of shower heads in these four families, only some other bacteria.
Dangerous population(shower head)
Previous studies have shown that the increase in cases of lung infection caused by atypical mycobacterium tuberculosis like Mycobacterium avium may be related to people taking more and more showers rather than bathing in bathtubs. Because the fine water droplets released from the shower head attach a large number of bacteria, they can easily reach the depths of people's lungs. Agence France Presse quoted Norman pace, the main author of the paper, as saying: "if you raise your head to welcome the first water flow from the shower nozzle, it means that the water containing a large amount of Mycobacterium avium falls on your face, which is very unsanitary." "if your immune system does not have some degree of defects, the shower is not dangerous, but there is a certain risk of disease," pace added. However, for pregnant women, the elderly or people struggling with diseases, their risk of lung infection caused by Mycobacterium avium is much higher than that of ordinary people due to the fragile body immune system.
Improvement measures(shower head)
"The findings do not emphasize that people should use baths instead of showers," said Laura Baumgartner, another author of the paper. The researchers found that compared with plastic shower heads, metal shower heads are more difficult to attach microorganisms. Selecting a metal nozzle with filtering device can effectively reduce the accumulation of bacteria. Nevertheless, because the shower nozzle is full of hidden places and gaps, it is difficult to clean. Even if it is cleaned with disinfectant, microorganisms will "come back" soon. After opening the shower nozzle, retreat outside the bathroom for one minute, which can effectively avoid a large number of germs sprayed with the first water injection. Pace and his team also found Mycobacterium avium on soap stains on plastic shower curtains and on the water surface of hot spring baths. They are taking air samples from subways, hospital waiting rooms, office buildings and homeless shelters.